This document provides information about microbiology for a B.Sc nursing course. It includes definitions of key terms like medical microbiology and Koch's phenomenon. It discusses the contributions of Robert Koch and Joseph Lister to the field. The document is divided into units, with the first unit covering an introduction and the second covering general characteristics of microbes. It includes short answer and essay questions about topics like bacterial cell structures, staining techniques, culture methods, and phases of bacterial growth. Diagrams are provided to illustrate some concepts.

1. MICROBIOLOGY
B.SC NURSING FIRST YEAR
MRUDHUL DIVAKARAN
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2. UNIT I
INTRODUCTION
SHORT ANSWERS
1. Define medical microbiology
2. Name two contribution of Robert Koch in
microbiology
3. Define Koch’s phenomenon
4. Name two contributions of Joseph Lister
Medical microbiology, also known as clinical
microbiology, is a subdiscipline of
microbiology dealing with the study of
microorganisms (parasites, fungi, bacteria,
viruses, and prions) capable of infecting
and causing diseases in humans (Baron et
al. 2007; Isenberg 2003).
He discovered the anthrax disease cycle (1876) and the
bacteria responsible for tuberculosis (1882) and cholera
(1883). For his discoveries in regard to tuberculosis, he
received the Nobel Prize for Physiology or Medicine in
1905.07-Dec-2021
Subjects Of Study: Bacillus anthracis anthrax b...
Awards And Honors: Nobel Prize (1905)
Born: December 11, 1843 Germany
Died: May 27, 1910 (aged 66)
Medical Definition of Koch's phenomenon
: the response of a tuberculous animal
to reinfection with tubercle bacilli
marked by necrotic lesions that develop
rapidly and heal quickly and caused by
hypersensitivity to products of the
tubercle bacillus.
He was the first person to
isolate bacteria in pure culture
(Bacillus lactis) using liquid
cultures containing either
Pasteur's solution of turnip
infusion and a special syringe to
dilute the inoculum and so can be
considered a co-founder of
medical microbiology with Koch,
who later isolated bacteria on solid
media.

3. UNIT II
GENERAL CHARACTERS OF MICROBES
SHORT ESSAY
1. Draw a neat labeled diagram of bacterial cell
and explain cell membrane.
2. Draw a neat labeled bacterial cell and
describe functions of bacterial cell structure.
The cell membrane, also called the plasma
membrane, is found in all cells and separates
the interior of the cell from the outside
environment. The cell membrane consists of a
lipid bilayer that is semipermeable. The cell
membrane regulates the transport of materials
entering and exiting the cell.
It is a gel-like matrix composed of water, enzymes, nutrients, wastes,
and gases and contains cell structures such as ribosomes, a chromosome,
and plasmids. The cell envelope encases the cytoplasm and all its
components. Unlike the eukaryotic (true) cells, bacteria do not have a
membrane enclosed nucleus.

4. 3. Draw a neat labeled bacterial cell. Explain
ribosomes
4. Draw a neat labeled bacterial cell. Explain
mesosomes with its functions.
Ribosomes are minute particles consisting
of RNA and associated proteins that
function to synthesize proteins. Proteins are
needed for many cellular functions such as
repairing damage or directing chemical
processes. Ribosomes can be found floating
within the cytoplasm or attached to the
endoplasmic reticulum.
A ribosome functions as a micro-machine for
making proteins
Mesosome is a convoluted membranous structure
formed in a prokaryotic cell by the invagination of the
plasma membrane. Its functions are as follows :
(1) These extensions help in the synthesis of the cell
wall and replication of DNA. They also help in the
equal distribution of chromosomes into the daughter
cells.

5. 5. Explain the steps in gram staining with
a neat labeled diagram
6. Explain negative staining
Gram-staining
Procedure
1.Crystal Violet (the
Primary Stain)
2.Iodine Solution (the
Mordant)
3.Decolorizer
(ethanol is a good
choice)
4.Safranin (the
Counterstain)
5.Water (preferably in
a squirt bottle)

6. 7. Explain enriched culture media 8. Explain the method of hanging drop preparation
Enrichment culture is the use of certain
growth media to favor the growth of a
particular microorganism over others,
enriching a sample for the microorganism of
interest. This is generally done by introducing
nutrients or environmental conditions that
only allow the growth of an organism of
interest.
The hanging drop technique is a well-established method for
examining living, unstained, very small organisms. The traditional
procedure employs a glass slide with a circular concavity in the centre
into which a drop of fluid, containing the 'microorganisms', hangs from
a coverslip.
What is the importance of hanging drop preparation?
Advantages
1.It is an important tool to study the bacterial motility along
with the shape, size and arrangement of the bacteria.
2.It does not distort the cell shape and arrangement.
3.Besides, the hanging drop method provides a better view
of motility in bacteria than the wet mount method.

7. 9. Explain special staining method (Albert
staining and Impregnation method) with
examples
Albert's staining technique is a type of special staining technique
since it is used to demonstrate a special structure in bacteria. It
is chiefly used to demonstrate metachromatic granules found in
Corynebacterium diphtheriae. This bacterium is responsible for the
disease diphtheria.
Procedure of Albert Staining
1.Prepare a smear on clean grease free slide.
2.Air dry and heat fix the smear.
3.Treat the smear with Albert’s stain and allow it to react for about 7
mins.
4.Drain of the excess stain do not water wash the slide with water.
5.Flood the smear with Albert’s iodine for 2 minutes.
6.Wash the slide with water, air dry and observe under oil immersion
lens.
impregnation in staining?
Silver and Gold impregnation are older staining
techniques that were commonly used years ago. They
are still used today occasionally to. observe detailed
structures and biological processes, such as.
intercellular junctions, motor end-plates and as seen
here, neuronal. cell processes.
The Golgi silver impregnation technique relies
on chemical preparation of thick blocks of tissue,
after which grains of metallic silver crystallize inside the
membranes of individual cells, producing a dense black
precipitate that highlights every detail of the cell body
and dendrites against a golden background.
Golgi's staining is achieved by impregnating aldehyde fixed nervous tissue
with potassium dichromate and silver nitrate. Cells thus stained are filled by
microcrystallization of silver chromate.
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8. 10. Explain differential culture media
Differential media contain compounds that
allow groups of microorganisms to be
visually distinguished by the appearance of
the colony or the surrounding media,
usually on the basis of some biochemical
difference between the two groups.
Examples of differential media include: Blood
agar (used in strep tests), which contains
bovine heart blood that becomes transparent
in the presence of hemolytic.
Streptococcuseosin methylene blue (EMB),
which is differential for lactose and sucrose
fermentation.0

9. 11. Draw a neat labeled bacterial cell.
Explain bacterial nucleus
12. Draw a neat labele diagram of bacterial
growth curve. Explain stationary phase and
decline phase.
Unlike the eukaryotic (true) cells, bacteria
do not have a membrane enclosed
nucleus. The chromosome, a single,
continuous strand of DNA, is localized,
but not contained, in a region of the cell
called the nucleoid. All the other cellular
components are scattered throughout the
cytoplasm
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Stationary Phase: Eventually, the
population growth experienced in the log
phase begins to decline as the available
nutrients become depleted and waste
products start to accumulate. Bacterial
cell growth reaches a plateau, or stationary
phase, where the number of dividing cells
equal the number of dying cells.
What is decline phase in biology?
In the last phase of the growth curve, the
death or decline phase, the number of
viable cells decreases in a predictable (or
exponential) fashion.

10. 13. Draw a neat labeled diagram of
bacterial growth curve. Explain about
lag phase
14. Draw a neat labeled bacterial cell. Explain
bacterial capsule.
bacterial growth curve
This lag phase is the period when the
bacteria are adjusting to the
environment. Following the lag phase is
the log phase, in which population grows in
a logarithmic fashion. As the population
grows, the bacteria consume available
nutrients and produce waste products.
What does lag phase mean?
: the period of time between the
introduction of a microorganism into a
culture medium and the time it begins
to increase exponentially.
The bacterial capsule is a large
structure common to many bacteria. It
is a polysaccharide layer that lies outside
the cell envelope, and is thus deemed
part of the outer envelope of a bacterial
cell. It is a well-organized layer, not
easily washed off, and it can be the
cause of various diseases.

11. 15. Explain anaerobic transport medium 16. Define culture method. Explain any two
culture methods in detail.
Anaerobic Transport Med. ( ATM) is a
mineral salt based semi-solid media.
Designed as a non-nutritive holding
Med., it maintains viability of
microorganisms through collection &
transport of clinical specimens. This
media is prepared, dispensed, &
packaged under oxygen-free
conditions.
Culture methods involve taking samples
from the field and detecting the presence of
microbe by culturing them. From the amount
of microbial species their influence on
corrosion is estimated. Culture media to grow
different microbes have been established.
streaking is a technique used to isolate a pure strain
from a single species of microorganism, often
bacteria. Samples can then be taken from the resulting
colonies and a microbiological culture can be grown on
a new plate so that the organism can be identified,
studied, or tested.

12. 17. Draw a neat labeled bacterial cell.
Explain Pili and Fimbriae.
18. Draw a neat labeled diagram of bacterial
growth curve. Explain about log phase.
Fimbriae and pili are hair-like appendages present
on the bacterial cell wall similar to flagella. ...
They are involved in the bacterial conjugation,
attachment to the surface and motility. They are
present in both Gram-positive and Gram-negative
bacteria but more prevalent in Gram-negative
bacteria.
Pili or fimbriae are protein structures that
extend from the bacterial cell envelope for a
distance up to 2 μm (Figure 3). They function
to attach the cells to surfaces. E. coli cells
can have up to 300 of these organelles.
The log phase (sometimes called the
logarithmic phase or the exponential phase)
is a period characterized by cell
doubling. ... If growth is not limited,
doubling will continue at a constant rate so
both the number of cells and the rate of
population increase doubles with each
consecutive time period.
log phase important?
For bacterial transformation the fact of
using log phase bacteria is the idea of
fitness, your bacteria are constantly in
division at this phase so when you
transform at this point you increase the
probability that the bacterium
transformed will divide rapidly

13. 19. Describe lawn culture and surface
plating (streaking)
20. Explain the stages of sporulation with the
help of neat labeled diagram.
streaking is a technique used to
isolate a pure strain from a single
species of microorganism, often
bacteria. ... If the agar surface grows
microorganisms which are all genetically
same, the culture is then considered as a
microbiological culture
The lawn culture provides a
uniform layer of bacterial
growth on a solid medium. It
is carried out by flooding the
surface of the solid media plate
with a liquid culture or
suspension of bacteria, pipetting
off the excess inoculum, and
finally incubating the plate
overnight at 37°C
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Stages of sporulation:
•Stage 0.
•Stage I: Axial filament formation stage.
•Stage II: forespore formation.
•Stage III: engulfment of forespore.
•Stage IV: synthesis of exosporium.
•Stage V: synthesis of dipicolonic cacid.

14. 21. Draw a neat labeled diagram of bacterial
growth curve. Explain stationary phase
and decline phase.
22. Define culture. Explain stab culture and
stroke culture.
Culture: In microbiology, the propagation of
microorganisms in a growth medium. Any body tissue or
fluid can be evaluated in the laboratory by using culture
techniques to detect and identify infectious processes.
Culture techniques can be used to determine sensitivity to
antibiotics. Cells may also be grown in culture.
STROKE CULTURE • Stroke culture is made
in tubes containing agar slope / slant. • Uses –
Provide a pure growth of bacterium for slide
agglutination and other diagnostic tests. 31.
STAB CULTURE • Prepared by puncturing a
suitable medium – gelatin or glucose agar
with a long, straight, charged wire.

15. 23. Explain the effect of oxygen and Ph on
bacterial nutrition.
24. Explain harmful effects of microorganisms.
In biochemistry, the oxygen effect refers to a tendency for
increased radiosensitivity of free living cells and
organisms in the presence of oxygen than in anoxic or
hypoxic conditions, where the oxygen tension is less than 1%
of atmospheric pressure (i.e., <1% of 101.3 kPa, 760 mmHg or
760 torr).
Bacteria are generally neutrophiles. They grow best at neutral
pH close to 7.0. Acidophiles grow optimally at a pH near 3.0.
Alkaliphiles are organisms that grow optimally between a pH of
8 and 10.5.
The harmful effects of microorganisms are
stated below. Bacteria: Causes diseases
like typhoid, diarrhoea and cholera. Fungi:
Causes numerous diseases in plants and
animals such as rust diseases in plants, fruit
rot in apple, red rot in sugar cane and ring
worm disease in human beings.

16. SHORT ANSWERS
1. Define anaerobic culture media
2. Name the parasites whose ova are detected in
stool microscopy
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3. Name the four phases of bacterial growth
4. Mention any two transport media
Anaerobic culture media contains reducing agents such as
cysteine. Various types of anaerobic culture media used in
diagnostic bacteriology laboratory. Pre-reduced, anaerobically
sterilized media are produced by different commercial suppliers,
which have extended shelf life of up to six months.
Bacterial colonies progress through four phases of growth: the lag
phase, the log phase, the stationary phase, and the death phase.
The generation time, which varies among bacteria, is controlled by
many environmental conditions and by the nature of the bacterial
species.

17. 5. Name the parasites whose cysts are
detected in stool microscopy
6. Define negative staining
7. Define sensitivity test 8. Define precipitation reaction
A sensitivity analysis is a test that determines the
“sensitivity” of bacteria to an antibiotic. It also
determines the ability of the drug to kill the bacteria.
The results from the test can help your doctor
determine which drugs are likely to be most effective
in treating your infection.
A precipitation reaction refers to the formation of an
insoluble salt when two solutions containing
soluble salts are combined. The insoluble salt that
falls out of solution is known as the precipitate,
hence the reaction's name. Precipitation reactions
can help determine the presence of various ions in
solution.
This includes pathogens such as Ascaris
spp. (roundworm), Necator americanus (hookworm),
Trichuris trichiura (whipworm), Strongyloides spp., and
Entamoeba histolytica amongst others
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13. Define agglutination
Agglutination is the clumping of particles. The word
agglutination comes from the Latin agglutinare (glueing to).
Agglutination is the process that occurs if an antigen is mixed
with its corresponding antibody called isoagglutinin. This term is
commonly used in blood grouping.

18. 9. Define slide agglutination
10. Define tube agglutination
11. Name two types of precipitation test
12. Define pili
Pili, also known as fimbriae, are proteinaceous, filamentous
polymeric organelles expressed on the surface of bacteria. They
range from a few fractions of a micrometer to > 20 μm in length and
vary from < 2 to 11 nm in diameter. Their functions include mediation
of cell-to-cell interactions, motility, and DNA uptake.
•Types of precipitation test.
•A) Gel diffusion.
•i) Agar gel single immunodiffusion test (Mancini test)
•ii) Agar Gel double immunodiffusion test (Ouchterlony test)
•B) Immunoelectrophoresis.
14. Name two bacterial exotoxins
•enterotoxin.
•neurotoxin.
•hemotoxin.
•cardiotoxin.
•phototoxin.
{ NAMES ONNU CHECK CHEYANE }
Exotoxins are a group of soluble proteins that are secreted by the
bacterium, enter host cells, and catalyze the covalent modification of
a host cell component(s) to alter the host cell physiology. Both Gram-
negative and Gram-positive bacteria produce exotoxins.

19. UNIT III
INFECTION CONTROL SHORT ESSAYS
1. Define sterilization .Explain sterilization by hot
air oven
2. Define sterilization. Explain sterilization by
moist heat
Sterilization may be defined as the statistically complete
destruction of all microorganisms including the most
resistant bacteria and spores. Sterilization may be defined
as the statistically complete destruction of all microorganisms
including the most resistant bacteria and spores.
Sterilization refers to any process that removes, kills, or
deactivates all forms of life (in particular referring to
microorganisms such as fungi, bacteria, spores, unicellular
eukaryotic organisms such as Plasmodium, etc.)
Hot air ovens use
extremely high
temperatures over
several hours to
destroy
microorganisms
and bacterial
spores. The ovens
use conduction
to sterilize
items by heating
the outside
surfaces of the
item, which then
absorbs the heat
and moves it
towards the center
of the item

20. 3. Define sterilization. Explain sterilization by
radiation
4. Define nosocomial infection. Explain urinary
tract infection in detail.
A urinary tract infection (UTI) is an infection
in any part of your urinary system —
your kidneys, ureters, bladder and
urethra. Most infections involve the lower
urinary tract — the bladder and the urethra.
Women are at greater risk of developing a
UTI than are men.

21. 5. Define sterilization. Explain the
principles and working of autoclave.
Sterilization refers to any process that removes, kills, or deactivates all
forms of life (in particular referring to microorganisms such as fungi,
bacteria, spores, unicellular eukaryotic organisms such as Plasmodium, etc.)
... After sterilization, an object is referred to as being sterile or aseptic.

22. 7. Define sterilization. Explain
sterilization by filtration
8. Define nosocomial infection. Explain wound
infection in detail
6. Explain iatrogenic infections and
congenital infections
Filtration is an interesting sterilization method in laboratories. It's
the only method that uses force to separate rather than to
kill. When you filter a liquid or gas, it passes through a pore,
which stops, or filters out, the passage of larger particles. ...
Pore sizes can be as small as .
Iatrogenic infection was defined as an infection after medical
or surgical management, whether or not the patient was
hospitalized. Relationship between prescription or procedure
and iatrogenic disease. Drug-Induced Disease.
Congenital infections affect the unborn fetus or newborn
infant. They are generally caused by viruses that may be
picked up by the baby at any time during the pregnancy up
through the time of delivery.
Nosocomial infections also referred to as healthcare-associated
infections (HAI), are infection(s) acquired during the process of
receiving health care that was not present during the time of
admission.
A wound infection occurs when germs, such as bacteria,
grow within the damaged skin of a wound. Symptoms can
include increasing pain, swelling, and redness. More
severe infections may cause nausea, chills, or fever.

23. 9. Define sterilization. Explain sterilization
by pasteurization
10. Define nosocomial infection. Explain
bacteremia and septicemia
The process of pasteurisation involves heating milk to
71.7°C for at least 15 seconds (and no more than
25 seconds). Because of the nature of the heat
treatment it sometimes referred to as the 'High
Temperature Short Time' (HTST) process. Once the
milk has been heated, it is then cooled very quickly to
less than 3°C.
Nosocomial infections also referred to as healthcare-associated
infections (HAI), are infection(s) acquired during the process of
receiving health care that was not present during the time of
admission.
Bacteremia is the
simple presence of
bacteria in the
blood while
Septicemia is the
presence and
multiplication of
bacteria in the blood.
Septicemia is also
known as blood
poisoning.
Bacteremia is the presence of viable bacteria in the circulating blood.
Most episodes of occult bacteremia spontaneously resolve, particularly those
caused by Streptococcus pneumoniae and Salmonella, and serious
sequelae are increasingly uncommon
Septicemia, or sepsis, is the clinical name for blood poisoning
by bacteria. It is the body's most extreme response to an infection.
Sepsis that progresses to septic shock has a death rate as high as
50%, depending on the type of organism involved.

24. 11. Define disinfection. Explain gaseous disinfection 12. Define infection. Describe the methods of
transmission of infection
Disinfection describes a process that eliminates many or all
pathogenic microorganisms, except bacterial spores, on inanimate
objects .In health-care settings, objects usually are disinfected by liquid
chemicals or wet pasteurization.
The mode of transmission can include direct contact, droplets, a
vector such as a mosquito, a vehicle such as food, or the airborne
route. The susceptible host has multiple portals of entry such as the
mouth or a syringe.
Infection occurs when germs enter your body and multiply,
resulting in disease. The four main types of infections
are viral, bacterial, fungal, and parasitic. Infection occurs
when germs enter your body and multiply, resulting in
disease.

25. 13. Define disinfection. Explain disinfection
using phenol (carbolic acid)
14. Define bio-medical waste .Describe the
different methods of bio-medical waste
treatment.
Phenolic compounds used as antiseptics or disinfectants include pure
phenol and substitution products with halogens and alkyl groups. They
act to denature and coagulate proteins and are general protoplasmic
poisons. Phenol (carbolic acid) is one of the oldest antiseptic
agents.
Can phenol be used as disinfectant?
Phenol is an antiseptic and disinfectant. It is active
against a wide range of micro-organisms including some
fungi and viruses, but is only slowly effective against
spores. Phenol has been used to disinfect skin and to
relieve itching.
Biomedical waste is defined as any waste, which is generated during the
diagnosis, treatment or immunisation of human beings or animals, or in
research activities pertaining thereto, or in the production or testing of
biologicals
What are the different bio waste treatment methods?
The primary methods of treating medical waste
are: Incineration. Autoclaves. Mechanical/Chemical Disinfection
{ ANS NOKANE }.

26. 15. Define disinfection. Explain
disinfection by using halogens
16. Define infection. Describe the sources of
infection.
Halogens. Other chemicals commonly used for disinfection
are the halogens iodine, chlorine, and fluorine. Iodine works
by oxidizing cellular components, including sulfur-containing
amino acids, nucleotides, and fatty acids, and destabilizing the
macromolecules that contain these molecules.
Why are halogens used as disinfectants?
They kill bacteria and other potentially harmful
microorganisms through a process known as sterilization.
Chlorine and bromine are also used in bleaching. Sodium
hypochlorite, which is produced from chlorine, is the active
ingredient of most fabric bleaches.
Infection: The invasion and multiplication of
microorganisms such as bacteria, viruses,
and parasites that are not normally present
within the body.
Common sources of infection
Sources, e.g. airborne, blood borne,
sexually transmitted, fecal, oral,
environment, stagnant water, warm-water
systems, animals.

27. 17. Define disinfection. Explain disinfection
by using alcohols.
18. Describe the role of nurse in infection
control programme.
Disinfection describes a process that
eliminates many or all pathogenic
microorganisms, except bacterial
spores, on inanimate objects (Tables 1
and 2). In health-care settings, objects
usually are disinfected by liquid
chemicals or wet pasteurization.
How are alcohols used as
disinfectants?
Isopropyl alcohol, particularly in
solutions between 60% and 90%
alcohol with 10 – 40% purified water,
is rapidly antimicrobial against
bacteria, fungi, and viruses. Once
alcohol concentrations drop below
50%, usefulness for disinfection drops
sharply.
What type of alcohol is used as a disinfectant?
Ethyl alcohol and isopropyl alcohol are
commonly used as disinfectants and antiseptics.
Both alcohols are effective at killing germs when
used in concentrations over 60 percent, but there's
some evidence that ethyl alcohol is less damaging
to your skin.
{ ITHINTE ANS NOKANE }
An infection control nurse is a registered nurse
(RN) who implements best practices for
halting the spread of viruses and bacteria
and delivers top care to patients who have
contracted infectious diseases.

28. SHORT ANSWERS
1. Name two gaseous disinfectants
2. Define pasteurization
3. Name two bacteria causing nosocomial infection
4. Define antiseptic
What is an antiseptic? An antiseptic is a
substance that stops or slows down the
growth of microorganisms. They're
frequently used in hospitals and other
medical settings to reduce the risk of
infection during surgery and other
procedures.
According to the CDC, the most common pathogens that cause
nosocomial infections are Staphylococcus aureus, Pseudomonas
aeruginosa, and E. coli.
Bacteria are the most common cause of nosocomial infections.
Common bacteria include E. coli and staph.
Nosocomial pathogens. Pathogens responsible for nosocomial
infections are bacteria, viruses and fungal parasites. These
microorganisms vary depending upon different patient populations,
medical facilities and even difference in the environment in which the
care is given.
pasteurization, heat-treatment process that
destroys pathogenic microorganisms in
certain foods and beverages. ... The
treatment also destroys most of the
microorganisms that cause spoilage and so
prolongs the storage time of food

29. 5. Define contagious disease
6. Define Primary infection
7. Define harmless waste
8. Give two functions of Alcohols
A contagious disease is a disease that is readily
spread (that is, communicated) by transmission
of a pathogen from an infected person to another
person.
A primary infection is the first time you are exposed
to and infected by a pathogen. During a primary
infection, your body has no innate defenses against
the organism, such as antibodies.
Alcohols are among the most common organic compounds.
They are used as sweeteners and in making perfumes,
are valuable intermediates in the synthesis of other
compounds, and are among the most abundantly produced
organic chemicals in industry.

30. 9. Define Secondary infection
10. Name two disinfectant used in hospital
11. Define carrier
12. Give two functions of Halogens
A carrier (colonized individual) is a person in
whom organisms are present and may be
multiplying, but who shows no clinical
response to their presence.
Carrier state. a condition in which a human
who is not himself sick harbors an infective
organism which may cause disease in
those to whom it is transmitted.
3 useful applications of halogens
•Fluorine is used in the manufacturing of
toothpaste.
•Chlorine is used in the purification of water.
•Bromine is used in the production of
photographic films as well as pesticides and
fumigants.
A secondary infection is an infection that
occurs during or after treatment for
another infection. It may be caused by
the first treatment or by changes in the
immune system. Two examples of a
secondary infection are: A vaginal yeast
infection after taking antibiotics to treat an
infection caused by bacteria
What is the best disinfectant for
hospitals?
•#1 Lysol Disinfectant Spray.
•#2 Clorox Healthcare Bleach
Germicidal Spray.
•#3 Clorox Hydrogen Peroxide Spray.
•#1 Clorox Disinfecting Wipes.
•#2 CaviWipes Disinfecting Towelettes.
•#3 Clorox Hydrogen Peroxide Wipes.

31. 13. Define sterilization
14. Define nosocomial infection
15. Give two examples of Acridine dyes
16. Define fumigation
Sterilization may be defined as the
statistically complete destruction of
all microorganisms including the
most resistant bacteria and spores.
Sterilization may be defined as the
statistically complete destruction of all
microorganisms including the most
resistant bacteria and spores.
Nosocomial infections also referred to
as healthcare-associated infections
(HAI), are infection(s) acquired
during the process of receiving
health care that was not present
during the time of admission.
ventilator-associated pneumonia,
Fumigation is a method of pest
control or the removal of harmful
micro-organisms by completely
filling an area with gaseous
pesticides—or fumigants—to
suffocate or poison the pests within.

32. 17. Name two opportunistic infections
associated with HIV infection
18. Define cold sterilization
19. Mention two functions of Glutaraldehyde
20. Define cross infection
A cross infection is the transfer of
harmful microorganisms, usually
bacteria and viruses. The spread of
infections can occur between people,
pieces of equipment, or within the body.
These infections can cause many
complications. So, medical professionals
work hard to ensure equipment safety and
a clean environment.
A glutaraldehyde solution of 0.1% to
1.0% concentration may be used as a
biocide for system disinfection and as
a preservative for long-term storage. It
is a sterilant, killing endospores in
addition to many microorganisms and
viruses.
Common opportunistic infections associated with HIV include:
•cryptococcal meningitis.
•toxoplasmosis.
•PCP (a type of pneumonia)
•oesophageal candidiasis.
•certain cancers, including Kaposi's sarcoma.
What is cold sterilization in microbiology?
Immersion of heat-sensitive instruments
into microbicidal fluids (such as
glutaraldehyde, orthophthalaldehyde, or
concentrated hydrogen peroxide) to rid them of
bacteria, fungi, mycobacteria, or viruses. See
also: sterilization

33. 21. Name two cutaneous infection
22. Name two methods of hospital waste
disposal
23. Give two examples of Aniline dyes
24. Define iatrogenic infection
25. Define sterilization
Cutaneous fungal infections are commonly caused by
dermatophytes. The prevalent dermatophytic infections in the
United States include tinea pedis, tinea corporis, tinea cruris,
tinea capitis, and tinea unguium.
For example,:
•Bacteria cause cellulitis, impetigo, and staphylococcal
(staph) infections.
•Viruses cause shingles, warts, and herpes simplex.
•Fungi cause athlete's foot and yeast infections.
•Parasites cause body lice, head lice, and scabies.
{ CHECK CHEYANE }
Other aniline dyes followed, such as fuchsin,
safranin, and induline. At the time of mauveine's
discovery, aniline was expensive.
Definition of aniline dye
a dye made by the use of aniline or one chemically related
to such a dye broadly : a synthetic organic dye.
Iatrogenic infection was defined as an infection after
medical or surgical management, whether or not the
patient was hospitalized
Iatrogenic: Due to the activity of a physician or
therapy. For example, an iatrogenic illness is an illness
that is caused by a medication or physician.
Sterilization refers to any process that
removes, kills, or deactivates all forms of
life (in particular referring to microorganisms
such as fungi, bacteria, spores, unicellular
eukaryotic organisms such as Plasmodium,
etc.)
The primary methods of treating medical
waste are:
•Incineration.
•Autoclaves.
•Mechanical/Chemical Disinfection.
•Microwave.
•Irradiation.
•Vitrification.

34. UNIT IV
PATHOGENICORGANISMS
LONG ESSAYS
1. Explain in detail the morphology, cultural
characteristics, pathogenicity,
laboratory diagnosis of streptococcus
pyogenes.

35. 2. Explain the morphology, habitat life cycle,
disease caused and laboratory diagnosis
of Wucheria Bancrofti.
habitat of Wuchereria bancrofti?
Wuchereria bancrofti, occurring in tropical Africa, parts of
Central and South America, as well in South-East Asia,
Brugia malayi, occurring in South and South-East Asia, as well
as Brugia timori (occurring on the island of Timor) are the
causative agents of lymphatic filarioses.

37. 3. Explain in detail the morphology, cultural
characteristics, pathogenicity,
laboratory diagnosis of Diplococci
(Pneumococcs).
the shape of Diplococcus pneumoniae?
Streptococcus pneumoniae is a gram-positive,
α-hemolytic, lancet-shaped diplococcus and
is bile soluble and optochin sensitive.
Diplococci characteristics
coccus arrangement
Pairs of cocci are called diplococci; rows or chains
of such cells are called streptococci; grapelike
clusters of cells, staphylococci; packets of eight or
more cells, sarcinae; and groups of four cells in a
square arrangement, tetrads.

38. 6. Classify the genus salmonella.
Salmonella is a genus of rod-shaped (bacillus) Gram-
negative bacteria of the family Enterobacteriaceae.

39. Explain in detail the morphology, cultural
characteristics, laboratory diagnosis,
pathogenicity and prophylaxis of Enteric fever.
Enteric fever is a bloodstream infection caused by the
bacteria Salmonella Typhi or Salmonella Paratyphi A, B, or C.
It is common in low resource settings and linked to poor water
quality and sanitation.
Morphology Family Enterobacteriaceae; S.
typhimurium is a gram
negative rod; motile, aerobic
and anaerobic. This bacteria is
one of the non-typhoid strains
of salmonella common in the
US.
Growth Conditions LB broth/agar (37°C); Aerobic.
What is the laboratory
diagnosis of enteric fever?
Testing for typhoid fever
A diagnosis of typhoid
fever can usually be
confirmed by analysing
samples of blood, poo, or
pee. These will be
examined under a
microscope for the
Salmonella typhi
bacteria that cause the
condition
The pathogenesis of typhoid fever depends upon a number of factors,
including infectious species, virulence, host's immunity, and infectious
dose. The larger the infectious dose, the shorter the incubation period, and
the higher the attack rate.
How can enteric fever be prevented?
Frequent hand-washing in hot, soapy water is the best way to
control infection. Wash before eating or preparing food and after using
the toilet. Carry an alcohol-based hand sanitizer for times when water
isn't available. Avoid drinking untreated water.

40. 4. Classify the genus clostridium. Explain in
detail the cultural characteristics,
pathogenesis, laboratory diagnosis,
prophylaxis of clostridium tetani.

42. 7. Name two medically important
spirochetes. Explain in detail the
morphology, cultural characteristics,
laboratory diagnosis, pathogenicity and
prophylaxis of Syphilis.

43. How is syphilis prevented?
Prevention
1.Abstain or be monogamous. The only certain way to
avoid syphilis is to avoid (abstain from) having sex. ...
2.Use a latex condom. Condoms can reduce your risk
of contracting syphilis, but only if the condom covers
the syphilis sores.
3.Avoid recreational drugs.

44. 8. Classify the genus Staphylococcus.
Explain in detail the morphology,
cultural characteristics, laboratory
diagnosis, pathogenicity of
Staphylococcus aureus.
What is the structure of Staphylococcus aureus?
Cell Structure and Metabolism
Staphylococcus aureus is a gram positive bacteria, which means
that the cell wall of this bacteria consists of a very thick
peptidoglycan layer. They are spherical, form clusters in 2 planes
and have no flagella
What is the pathogenicity of Staphylococcus aureus?
Staphylococcus aureus is an extraordinarily versatile pathogen that can
survive in hostile environmental conditions, colonize mucous membranes
and skin, and can cause severe, nonpurulent, toxin-mediated disease or
invasive pyogenic infections in humans.

45. 9. Explain in detail the morphology, cultural
characteristics, laboratory diagnosis,
pathogenicity and prophylaxis of vibrio
cholerae.
.
Are all Vibrio cholera pathogenic?
Numerous free-living vibrios are known, some potentially
pathogenic. Until 1992, cholera was caused by only two serotypes,
Inaba (AC) and Ogawa (AB), and two biotypes, classical and El Tor, of
toxigenic O group 1 V cholerae.

46. 10. Classify the genus Mycobacterium. Explain
in detail, about the morphology, cultural
characteristics, laboratory diagnosis,
pathogenicity and prophylaxis of
Mycobacterium tuberculosis
What is the laboratory diagnosis of tuberculosis?
There are two kinds of tests that are used to detect TB bacteria in the
body: the TB skin test (TST) and TB blood tests. A positive TB skin
test or TB blood test only tells that a person has been infected with TB
bacteria.
What is the prophylaxis for TB?
6.1.
The standard regimen for treatment of latent
TB infection is nine months isoniazid, also
known as isoniazid prophylaxis therapy (IPT).
Pyrodoxine should be given with isoniazid
(Udani et al. 1971).

47. pathogenicity of Mycobacterium tuberculosis
How can you prevent Mycobacterium
tuberculosis?
The risk of infection can be
reduced by using a few simple
precautions:
1.good ventilation: as TB can remain
suspended in the air for several hours
with no ventilation.
2.natural light: UV light kills off TB
bacteria.
3.good hygiene: covering the mouth
and nose when coughing or sneezing
reduces the spread of TB bacteria.

48. 11. Explain in detail the morphology,
pathogenicity, clinical symptoms and
prophylaxis of Rabies virus
The rabies virus is a negative-sense, non-segmented,
single-stranded RNA virus measuring approximately
60 nm × 180 nm. It is composed of an internal protein
core or nucleocapsid, containing the nucleic acid, and
an outer envelope, a lipid-containing bilayer covered
with transmembrane glycoprotein spikes
What is prophylaxis of rabies?
Bite by all warm blooded animals
necessitates post-exposure prophylaxis.
As rabies is practically 100% fatal, bites by
dogs and cats in particular must be
considered as a “medical emergency” and
the “life-saving” post exposure prophylaxis
must be provided immediately.

49. 12. Explain in detail about the morphology,
pathogenicity, clinical symptoms, lab
diagnosis and prophylaxis of HIV.
What is HIV microbiology?
HIV is an RNA retrovirus that infects specific white
blood cells with the CD4 receptor on their surface
(CD4+ cells). CD4 is hijacked by HIV which uses it to
gain access to the cell. Once inside the cell, the virus's
genetic material, RNA, is converted to DNA in a
process called reverse transcription.
What is the pathogenesis for HIV?
HIV pathogenesis is thought of as a chronic infection
involving slow degradation of immunity that
ultimately leads to AIDS. This scenario, however,
could reflect the decay of an immune system mortally
wounded during acute HIV infection
Symptomatic HIV infection
•Fever.
•Fatigue.
•Swollen lymph nodes — often one of the first
signs of HIV infection.
•Diarrhea.
•Weight loss.
•Oral yeast infection (thrush)
•Shingles (herpes zoster)
•Pneumonia.
Pre-exposure prophylaxis (or PrEP) is
medicine taken to prevent getting HIV.
PrEP is highly effective for preventing
HIV when taken as prescribed. PrEP
reduces the risk of getting HIV from
sex by about 99%. PrEP reduces the
risk of getting HIV from injection drug
use by at least 74%.
What is the first drug given for HIV
prophylaxis?
FDA Approves Truvada PrEP, First Drug for
HIV Prevention.

50. 13. Explain the morphology, pathogenicity,
clinical symptoms, laboratory diagnosis of
HBsAg (Hepatitis ‘B’ virus).
14. Explain the morphology, life cycle,
pathogenicity, laboratory diagnosis of
Entamoeba histolytica.
morphology, in biology, the study of the size, shape, and
structure of animals, plants, and microorganisms and of
the relationships of their constituent parts. The term refers
to the general aspects of biological form and arrangement of the
parts of a plant or an animal.
Pathogenicity can be defined as the capacity of a
microbe to cause damage in a host while virulence
refers to the degree of damage caused by the microbe
(Casadevall and Pirofski, 1999).
clinical
symptoms?
Definition.
Any
objective
evidence
of disease
or of a
patient's
condition
founded
on clinical
observatio
n.
A laboratory diagnosis of hepatitis B (HBV) infection is
dependent upon the detection of hepatitis B surface antigen
in serum. The distinction between acute and chronic infection
relies on the detection of other serological markers. Serum-
based assays can now detect and quantify the viral DNA.
The bacteria life cycle consists of the lag
phase, the log or exponential phase, the
stationary phase and the death phase.
Factors that influence bacterial growth bear
heavily on this cycle.
{ EE 2 QUE ANS CHECK CHEYANE }

51. 15. Explain the morphology, pathogenesis,
clinical symptoms, laboratory diagnosis
and prophylaxis of polio virus.
The viral particle is about 30 nm in diameter with icosahedral
symmetry. Because of its short genome and its simple composition—
only RNA and a nonenveloped icosahedral protein coat that
encapsulates it, poliovirus is widely regarded as the simplest
significant virus.
Virus: Poliovirus
Family: Picornaviridae
Species: Enterovirus C
Genus: Enterovirus
pathogenesis of poliovirus?
During intestinal replication, the virus
invades local lymphoid tissue and may
enter the bloodstream, and then infect
cells of the central nervous system.
Poliovirus-induced destruction of
motor neurons of the anterior horn of
the spinal cord and brain stem cells
results in distinctive paralysis.
Signs and symptoms,
which can last up to
10 days, include:
•Fever.
•Sore throat.
•Headache.
•Vomiting.
•Fatigue.
•Back pain or stiffness.
•Neck pain or stiffness.
•Pain or stiffness in the
arms or legs.
The best prevention against polio is a series
of four vaccine shots in the arm or leg. The
inactivated polio vaccine used in the United
States is very effective and safe, and cannot
cause polio. The recommended vaccination
schedule for children is based on age: First
shot when 2 months old
{ANS CHECK CHEYANE }

52. 16. Name the malarial parasites. Explain
morphology, life cycle, pathogenicity,
laboratory diagnosis of Malarial Parasite
Parasite morphology: Malarial parasites form four
developmental stages in humans (hepatic schizonts
and then intraerythrocytic trophozoites, schizonts and
gamonts) and three developmental stages in
mosquitoes (ookinetes, oocysts and sporozoites).
Malarial infection begins when a person is bitten by an
infected female anopheles mosquito and Plasmodium
spp (species) parasites in the form of sporozoites are
injected into the bloodstream. The sporozoites travel
to the liver, multiplying asexually over the next 7–10
days. During this time there are no symptoms.

53. 17. Explain the morphology, life cycle, lesions caused,
laboratory diagnosis of Ascaris lumbericosides.
18. Explain in detail the morphology, cultural
characteristics, pathogenictiy, laboratory
diagnosis, prophylaxis of corynebacterium
diptheriae.
laboratory diagnosis of Ascaris lumbricoides?
The standard method for diagnosing ascariasis is
by identifying Ascaris eggs in a stool sample using a
microscope. Because eggs may be difficult to find in light
infections, a concentration procedure is recommended.
morphology of Ascaris?
Adult: The round worm resembles to earthworm. It
is elongated tapering to both end, anterior being
thinner than posterior. Freshly excreted worm is
yellowish pink in color, which gradually changes to
white.
morphology of
Corynebacterium diphtheriae?
C. diphtheriae is a
pleomorphic, club-shaped,
Gram positive bacillus that is
catalase positive, non-motile,
non-spore forming, and non-
acid fast. On Gram stain, the
organisms are typically
described as having a “picket
fence” or
“Chinese character”
morphology
Corynebacterium diphtheriae
diagnosis?
Doctors usually decide if a
person has diphtheria by
looking for common signs and
symptoms. They can swab
the back of the throat or
nose and test it for the
bacteria that cause
diphtheria. A doctor can also
take a sample from an open
sore or ulcer and try and grow
the bacteria.

54. 19. Explain the morphology, life cycle,
disease caused and laboratory diagnosis of
Ancylostoma duodenale.
20. Explain the pathogensis, clinical features,
diagnosis of Salmonella typhi.
What are the features of Salmonella?
Salmonellosis is a disease caused by the bacteria Salmonella. It is usually
characterized by acute onset of fever, abdominal pain, diarrhoea, nausea
and sometimes vomiting. The onset of disease symptoms occurs 6–72
hours (usually 12–36 hours) after ingestion of Salmonella, and illness lasts
2–7 days.
How is Salmonella typhi diagnosed?
The only way to know for sure if an illness is typhoid fever or paratyphoid
fever is to have a sample of blood or stool (poop) tested for Salmonella Typhi
or Salmonella Paratyphi. If you have a fever and feel very ill, see a doctor
immediately.
Intestinal hookworm disease in humans
is caused by Ancylostoma duodenale, A.
ceylanicum, and Necator americanus

55. What is diagnosis of ancylostoma
Duodenale?
The standard method for diagnosing the
presence of hookworm is by
identifying hookworm eggs in a stool
sample using a microscope. Because
eggs may be difficult to find in light
infections, a concentration procedure is
recommended.

56. SHORT ANSWERS
1. Name two gram positive bacteria
2. Name two specific test done for Syphilis
detection
3. Name two RNA viruses
4. Name two DNA viruses
DNA viruses comprise important pathogens
such as herpesviruses, smallpox viruses,
adenoviruses, and papillomaviruses, among
many others.
RNA Viruses. Human diseases causing RNA
viruses include Orthomyxoviruses, Hepatitis C
Virus (HCV), Ebola disease, SARS, influenza,
polio measles and retrovirus including adult
Human T-cell lymphotropic virus type 1 (HTLV-
1) and human immunodeficiency virus (HIV).
The Gram-positive bacteria
include staphylococci ("staph"),
streptococci ("strep"), pneumococci,
and the bacterium responsible for
diphtheria (Cornynebacterium
diphtheriae) and anthrax (Bacillus
anthracis)
Tests used to screen for syphilis include:
•Venereal disease research laboratory (VDRL)
test. The VDRL test checks blood or spinal fluid
for an antibody that can be produced in people
who have syphilis. ...
•Rapid plasma reagin (RPR) test. The RPR test
also finds syphilis antibodies.
•Rapid immunochromatographic test.
{ ITHANO ENN ARIYILLA CHECK
CHEYANE }

57. 5. Name the specific test done for Enteric fever
6. Name 4 viruses causing aseptic meningitis
7. Give two examples of Gram positive cocci
8. Give two example of Aerobic bacterias
Viral causes include the following: Enteroviruses -
coxsackievirus, echovirus, poliovirus. Herpes
simplex virus (HSV) types 1 and 2 (HSV-1, HSV-2)
Varicella-zoster virus.
The Widal test is one method that may be
used to help make a presumptive diagnosis
of enteric fever, also known as typhoid
fever.
Gram-positive cocci include Staphylococcus
(catalase-positive), which grows clusters, and
Streptococcus (catalase-negative), which grows in
chains. The staphylococci further subdivide into
coagulase-positive (S. aureus) and coagulase-
negative (S. epidermidis and S
Examples of high G+C gram-positive bacteria that are
human pathogens include Mycobacterium tuberculosis,
which causes tuberculosis; M. leprae, which causes
leprosy (Hansen's disease); and Corynebacterium
diphtheriae, which causes diphtheria. Clostridia
spp.
Aerobic Bacteria List:
•E. Coli.
•Citrobacter.
•Klebsiella.
•Proteus.
•Salmonella.
•Achromobacter.

58. 9. Mention the use of TAB vaccine
11. Name three diseases caused by clostridium
12. Name two diseases caused by spirochetes
Vaccine TAB is the vaccine that
has the killed bacteria in it.
Complete answer: The vaccine
TAB is used for the prevention
of the Typhoid. This vaccine
helps in preventing the typhoid,
paratyphoid A and the
paratyphoid B.
Diseases Caused by Clostridia
•Botulism. Botulism may occur without
infection if toxin is ingested, injected, or
inhaled. ...
•Clostridioides (formerly, Clostridium) difficile–
induced colitis. ...
•Gastroenteritis. ...
•Soft-tissue infections. ...
•Tetanus. ...
•Clostridial necrotizing enteritis. ...
•Neutropenic enterocolitis (typhlitis)
Of mammalian pathogens, some of the most
invasive come from a group of bacteria known
as the spirochetes, which cause diseases such
as syphilis, Lyme disease, relapsing fever
and leptospirosis.

59. 13. Name two acid fast bacteria 14. Give two examples of Gram negative cocci
16. Name two sexually transmitted
diseases
Common acid-fast bacteria of
medical importance
include Mycobacterium
tuberculosis, Mycobacterium
leprae,Mycobacterium avium-
intracellulare complex, and
Nocardia species.
Sexually transmitted diseases
(STDs) are infections transmitted
from an infected person to an
uninfected person through sexual
contact. STDs can be caused by
bacteria, viruses, or parasites.
Examples include gonorrhea,
genital herpes, human
papillomavirus infection,
HIV/AIDS, chlamydia, and
syphilis.

60. 17. Mention the purpose of Coombs test 19. Name two nematodes
20. Name three bacteria causing urinary tract
infection
The Coombs test will help your doctor
determine if you have antibodies in
your bloodstream that are causing
your immune system to attack and
destroy your own red blood cells. If
your red blood cells are being destroyed,
this can result in a condition called
hemolytic anemia.
Six intestinal nematodes commonly infect
humans: Enterobius vermicularis
(pinworm), Trichuris trichiura (whipworm),
Ascaris lumbricoides (large roundworm),
Necator americanus and Ancylostoma
duodenale (hookworms), and Strongyloides
stercoralis.
Urinary tract infections (UTIs) are a severe
public health problem and are caused by a
range of pathogens, but most commonly
by Escherichia coli, Klebsiella pneumoniae,
Proteus mirabilis, Enterococcus faecalis
and Staphylococcus saprophyticus.
24. Name two bacteria causing diarrhea
he most frequently identified organisms
causing bacterial diarrhea
are Escherichia coli (most common
worldwide), Shigella, Salmonella,
Campylobacter (most common in
children), Yersinia, and Clostridium spp.

61. 21. Name four clinical syndromes caused
by E.coli
22. Name the motility test done to detect
vibrio cholera
23. Give two examples of Gram negative bacilli
Escherichia coli is one of the most
frequent causes of many common
bacterial infections,
including cholecystitis, bacteremia,
cholangitis, urinary tract infection (UTI),
and traveler's diarrhea, and other clinical
infections such as neonatal meningitis and
pneumonia.
Escherichia coli is the most common gram-negative
pathogen. Other gram-negative organisms responsible
for HAI are Klebsiella, Pseudomonas, Enterobacter,
Acinetobacter, Serratia, Haemophilus, and Salmonella
spp.
Gram-negative bacteria are the most common primary
pathogens: ○ Often, these organisms are part of the
normal flora, but they may become opportunistic. ○
Commonly isolated Gram-negative organisms include
Pseudomonas, Klebsiella, Proteus, Salmonella,
Providencia, Escherichia, Morganella, Aeromonas, and
Citrobacter.
Isolation and identification of Vibrio cholerae
serogroup O1 or O139 by culture of a stool
specimen remains the gold standard for the
laboratory diagnosis of cholera. Cary Blair media is
ideal for transport, and the selective thiosulfate–
citrate–bile salts agar (TCBS) is ideal for isolation
and identification. { CHECK CHEYANE }

62. 25. Name two zoonotic disease
26. Give two examples of spore bearing Gram
positive bacilli
27. Name two vectors and the diseases
transmitted by them
28. Define Focal sepsis
The zoonotic diseases of most concern in
the U.S. are:
•Zoonotic influenza.
•Salmonellosis.
•West Nile virus.
•Plague.
•Emerging coronaviruses (e.g., severe acute
respiratory syndrome and Middle East
respiratory syndrome)
•Rabies.
•Brucellosis.
•Lyme disease.
The gram-positive spore-forming bacilli are
the Bacillus and Clostridium species.
Infection present, or assumed to be present, in a
limited area of the body, such as the teeth, tonsils or
sinuses. In the past, all sorts of disorders were said
to be due to focal sepsis, but as medical knowledge
has grown, such attribution has become rare.

63. 29. Name four parasites causing anemia
30. Define zoonoses
31. Give two examples of Gram positive bacilli
32. Name two E.coli causing diarrhea
A zoonosis is an infectious disease
that has jumped from a non-human
animal to humans. Zoonotic
pathogens may be bacterial, viral or
parasitic, or may involve
unconventional agents and can
spread to humans through direct
contact or through food, water or the
environment.
In addition to the nutritional status, iron
deficiency anemia has also been
associated with infection by intestinal
parasites, namely Schistosoma
mansoni, hookworms, T. trichiura and
A. lumbricoides
Gram Positive Bacilli
•Amoxicillin.
•Spore.
•Metronidazole.
•Toxin.
•Diarrhea.
•Gram Staining.
•Anthrax.
•Bacterium.
coli (EIEC), enterohaemorrhagic
E. coli (EHEC) and
enteroaggregative E. coli
(EAggEC) produce an inflammatory
diarrhoea. ETEC are a major cause of
diarrhoea in infants (up to three
episodes per year) and travellers.

64. 33. Name two parasites transmitted by faeco
oral route
34. Define Mycoplasma
Mycoplasma (plural mycoplasmas or
mycoplasmata) is a genus of bacteria that
lack a cell wall around their cell
membranes. This characteristic makes them
naturally resistant to antibiotics that target cell
wall synthesis (like the beta-lactam antibiotics).
They can be parasitic or saprotrophic.
Domain: Bacteria
Genus: Mycoplasma; J.Nowak 1929
Many common infections are spread by fecal-
oral transmission, including E. coli,
adenovirus, campylobacter, coxsackie
virus, giardia, hepatitis A, Salmonella, and
Shigella.

65. UNIT V
IMMUNITY SHORT ESSAY
1. Define carriers. Describe the types of carriers.
2. Define immunity .Explain Herd immunity and
local immunity
A carrier (colonized individual) is a person in whom
organisms are present and may be multiplying, but who
shows no clinical response to their presence.
The types of carrier are:
•common carriers.
•private carriers.
•other types of carriers with special rights and duties.
Immunity is a biological term that describes
a state of having sufficient biological
defences to avoid infection, disease, or
other unwanted biological invasion. Innate, or
nonspecific, immunity is the natural resistance
with which a person is born.

66. 3. Define immunization. Describe
immunization schedule
4. Define vectors. Describe the types of vectors
Immunization: A process by which a person becomes
protected against a disease through vaccination. This
term is often used interchangeably with vaccination or
inoculation.
Vaccine Schedule
BCG, Hep B birth
dose, OPV-O
At Birth
Pentavalent (DPT +
Hep B + Hib), OPV
6 weeks, 10 weeks
and 14 weeks
Measles and
Vitamin A
9-12 months
DPT booster, OPV
booster, Measles2*
16-24 months
DPT booster 5-6 years
A vaccination schedule is a series of vaccinations,
including the timing of all doses, which may be
either recommended or compulsory, depending on the
country of residence.
A vector is a living organism that transmits an infectious
agent from an infected animal to a human or another
animal. Vectors are frequently arthropods, such as
mosquitoes, ticks, flies, fleas and lice.
The four major types of vectors are plasmids, viral vectors,
cosmids, and artificial chromosomes. Of these, the most
commonly used vectors are plasmids.

67. 5. Define auto immunity. Explain any two
autoimmune diseases.
6. Define vaccines. Differentiate between Salk
vaccine and Sabin vaccine
autoimmunity, the state in which the immune system reacts
against the body's own normal components, producing disease
or functional changes.
Autoimmunity is the system of immune responses of an organism
against its own healthy cells, tissues and other body normal
constituents. Any disease resulting from this type of immune response is
termed an "autoimmune disease".
According to The
Autoimmune
Registry, the top
10 most common
autoimmune
diseases
include:
•Rheumatoid
arthritis.
•Hashimoto's
autoimmune
thyroiditis.
•Celiac disease.
•Graves' disease.
•Diabetes mellitus,
type 1.
•Vitiligo.
•Rheumatic fever.
•Pernicious
anemia/atrophic
gastritis.
Vaccine: A preparation that is used to stimulate the
body's immune response against diseases. Vaccines ar
usually administered through needle injections, but some
can be administered by mouth or sprayed into the nose.

68. 7. Define antibody. Write the
functions of IgM immunoglobulin
8. Define hypersensitivity reactions. Explain type IV
hypersensitivity reactions
IgM not only serves as the first line of
host defense against infections but
also plays an important role in immune
regulation and immunological tolerance.
For many years, IgM is thought to
function by binding to antigen and
activating complement system
Hypersensitivity reactions (HR) are immune responses that are exaggerated
or inappropriate against an antigen or allergen
Type four hypersensitivity reaction is a cell-
mediated reaction that can occur in
response to contact with certain allergens
resulting in what is called contact dermatitis or
in response to some diagnostic procedures as
in the tuberculin skin test. Certain allergens
must be avoided to treat this condition.

69. 9. Define antibody. Write the functions of IgE
immunoglobulin
10. Define hypersensitivity. Explain type I
Anaphylactic reaction in detail.
An antibody (Ab), also
known as an
immunoglobulin (Ig), is a
large protein produced by
B-cells that is used by the
immune system to
identify and neutralize
foreign objects, such as
bacteria and viruses. ...
Using this binding
mechanism, an antibody
can tag a microbe or an
infected cell
Immunoglobulin E (IgE) antibodies are well known for their role
in mediating allergic reactions, and their powerful effector functions
activated through binding to Fc receptors FcεRI and FcεRII/CD23.
Hypersensitivity reactions are exaggerated or inappropriate
immune responses to benign antigens. It is the immune
response, not the antigens that are harmful to the host.
An excessive or abnormal sensitivity to a substance. A person
who is hypersensitive to a certain drug will often suffer a severe
allergic reaction (see allergy) if given the drug.
Type I hypersensitivity is also known as an
immediate reaction and involves immunoglobulin E
(IgE) mediated release of antibodies against the
soluble antigen. This results in mast cell
degranulation and release of histamine and other
inflammatory mediators

70. 11. Explain the effect of water in bacterial nutrition. 12. Explain ELISA reaction
Enzyme-linked immunosorbent assay
(ELISA) is a method of target antigen (or
antibody) capture in samples using a
specific antibody (or antigen), and of target
molecule detection/quantitation using an
enzyme reaction with its substrate.
If you measure the water activity of any material, you will know which
bacteria, molds, or fungi can grow on and in it. By reducing water
activity, you can rule out the growth of certain classes of
microbes. At low water activities you can preclude the growth of
anything at all.
What is the effect of water in bacterial nutrition?
For growth and nutrition of bacteria, the minimum nutritional
requirements are water, a source of carbon, a source of
nitrogen and some inorganic salts. Water is the vehicle of
entry of all nutrients into the cell and for the elimination of
waste products.
What is the effect of bacteria in water?
The presence of coliform bacteria, specifically E. coli (a type of
coliform bacteria), in drinking water suggests the water may
contain pathogens that can cause diarrhea, vomiting, cramps,
nausea, headaches, fever, fatigue, and even death sometimes.
Why do bacteria need water?
Moisture – Bacteria need moisture in
order to grow. This is why they grow on
foods with high moisture content such as
chicken. Foods that are dehydrated or
freeze-dried can be stored for much longer
as the moisture has been removed. Food
– Food provides energy and nutrients for
bacteria to grow.

71. 13. Define antibody. Write the functions of IgA
immuniblobulin
14. Define immunity. Explain natural
passive immunity.
Immunoglobulin A (IgA) is
the most abundant type of
antibody in the body,
comprising most of the
immunoglobulin in
secretions and a significant
amount of circulating
immunoglobulin. In
secretions, it serves to
protect the mucosal
tissues from microbial
invasion and maintain
immune homeostasis with
the microbiota.
Immunity is a biological term that describes a state of
having sufficient biological defences to avoid infection,
disease, or other unwanted biological invasion. Innate, or
nonspecific, immunity is the natural resistance with which a
person is born.
Passive immunity can occur naturally, such as when an infant receives a
mother's antibodies through the placenta or breast milk, or artificially,
such as when a person receives antibodies in the form of an injection
(gamma globulin injection).

72. 15. Describe antibiotic sensitivity test (AST) 16. Explain Widal test
The Widal test measures the capacity of antibodies against LPS
and flagella in the serum of individuals with suspected typhoid
fever to agglutinate cells of S. Typhi; the test was introduced over a
century ago and it is still widely used [20].
What is the normal range of Widal test?
Conclusion: In case of singular Widal test, baseline values for the normal
range was found to be 1:20 - 1:80 for all the antigens (TO, TH, AO, AH, BO,
BH), except BH, for which it was 1:20-1:40.
Widal Test is an agglutination test which detects the presence of
serum agglutinins (H and O) in patients serum with typhoid and
paratyphoid fever
Antibiotic susceptibility testing, or AST, is a widely-used
method of evaluating antibiotic resistance and
determining patient treatment plans in clinical
settings. There are a number of different methods of
AST such as agar dilution, broth dilution and disc
diffusion assays.
What is AST system?
A next-generation phenotyping system is seeking to
revolutionize antibiotic susceptibility testing (AST) in
an effort to begin treating patients faster and to combat
antibiotic resistance.

73. 17. Define immunity. Explain
natural passive immunity
18. Define immunity. Explain artificial active
immunity
the quality or state of being immune especially : a
condition of being able to resist a particular
disease especially through preventing development
of a pathogenic microorganism or by counteracting
the effects of its products — see acquired immunity,
active immunity, natural immunity, passive immunity.
immunity.
Passive immunity can occur naturally, such as when
an infant receives a mother's antibodies through
the placenta or breast milk, or artificially, such as
when a person receives antibodies in the form of an
injection (gamma globulin injection).
An active immunity acquired
by vaccination (i.e. the injection of vaccine
containing active antigens to prevent the
development of the disease in the future).
Vaccine-induced immunity
Also known as artificial active immunity, a
person can build a resistance to a disease
following an immunization. An
immunization is defined as the process by
which someone becomes protected
against a specific disease via the
administration of a vaccine

74. 19. Explain VDRL test 20. Explain Oral Polio Vaccine
What oral polio vaccine means?
The action of oral polio vaccine (OPV) is two-
pronged. OPV produces antibodies in the blood
('humoral' or serum immunity) to all three types of
poliovirus, and in the event of infection, this
protects the individual against polio paralysis by
preventing the spread of poliovirus to the nervous
system.
Definition. The VDRL test is a screening test
for syphilis . It measures substances
(proteins), called antibodies , which your body
may produce if you have come in contact with
the bacteria that cause syphilis
Blood is generally drawn from a vein at the
crease of the elbow or the back of the hand.
This blood sample will then be sent to a
laboratory and tested for the antibodies
produced as a result of syphilis. The VDRL
test doesn't require you to fast or stop taking
any medications.

75. 21. Define immunity. Explain natural
active immunity
22. Define immunity .Explain innate immunity
Immunity is a biological term that describes a state of having
sufficient biological defences to avoid infection, disease, or
other unwanted biological invasion. Innate, or nonspecific, immunity
is the natural resistance with which a person is born.
Naturally acquired active immunity occurs when the person
is exposed to a live pathogen, develops the disease, and
becomes immune as a result of the primary immune
response. Once a microbe penetrates the body's skin,
mucous membranes, or other primary defenses, it interacts
with the immune system.
INNATE IMMUNITY. Innate, or nonspecific, immunity is the defense
system with which you were born. It protects you against all
antigens. Innate immunity involves barriers that keep harmful materials
from entering your body. These barriers form the first line of defense in
the immune response.

76. 23. Define vaccine. Describe BCG vaccine.
Vaccine: A preparation that is used to
stimulate the body's immune
response against diseases. Vaccines
are usually administered through
needle injections, but some can be
administered by mouth or sprayed into
the nose.
What is the BCG vaccine and why is it
given?
This vaccine is used to prevent
tuberculosis (TB) in people who have
not been infected with the disease but
are at a high risk of getting it.
vak-SEEN) A vaccine used to prevent tuberculosis (TB) in people who
are at a high risk of TB or where TB is common. It is rarely given in the
U.S. It is made from a weakened form of a bacterium called
Mycobacterium bovis (bacillus Calmette-Guérin), which is similar to the
bacteria that cause TB.

77. SHORT ANSWERS
Define active immunity
Name two live vaccines
Mention the four types of blood group
Name two types of hyper sensitivity
Live-attenuated vaccines
•Measles, mumps, rubella (MMR combined vaccine)
•Rotavirus.
•Smallpox.
•Chickenpox.
•Yellow fever.
There are 4 main blood groups (types of blood)
– A, B, AB and O. Your blood group is
determined by the genes you inherit from your
parents. Each group can be either RhD
positive or RhD negative, which means in total
there are 8 blood groups.
The four types of hypersensitivity are:
•Type I: reaction mediated by IgE antibodies.
•Type II: cytotoxic reaction mediated by IgG or
IgM antibodies.
•Type III: reaction mediated by immune
complexes.
•Type IV: delayed reaction mediated by cellular
response.

78. Name two bacterial vaccine
Name two autoimmune disease of thyroid gland
Give two examples of biological vectors
Define immunity
The bacterial vaccines (i.e., diphtheria,
tetanus, pertussis, H. influenzae type b, and
pneumococcus) should be administered to all
HIV-infected children according to the routine
childhood schedule.
Autoimmune thyroid diseases consist of two
subgroups: autoimmune thyroiditis (AIT)
and Graves' disease. The AIT is the most
common human autoimmune disease.
What are the most common autoimmune diseases?
Here are 14 of the most common ones.
1.Type 1 diabetes. The pancreas produces the hormone
insulin, which helps regulate blood sugar levels. ...
2.Rheumatoid arthritis (RA) ...
3.Psoriasis/psoriatic arthritis. ...
4.Multiple sclerosis. ...
5.Systemic lupus erythematosus (SLE) ...
6.Inflammatory bowel disease. ...
7.Addison's disease. ...
8.Graves' disease.
Immunity is a biological term that
describes a state of having
sufficient biological defences to
avoid infection, disease, or other
unwanted biological invasion.
Innate, or nonspecific, immunity is
the natural resistance with which a
person is born.
Mosquitoes, ticks, fleas and lice are
examples of biological vectors and are
often responsible for serious blood-
borne diseases, such as malaria.

79. Mention two uses of ELISA test
Define antibodies
Mention four types of immunoglobulin
Mention two uses of immunofluorescence
antibody, also called immunoglobulin,
a protective protein produced by the
immune system in response to the
presence of a foreign substance,
called an antigen. Antibodies recognize
and latch onto antigens in order to
remove them from the body.
Classes of immunoglobulins. The five primary
classes of immunoglobulins are IgG, IgM, IgA,
IgD and IgE. These are distinguished by the
type of heavy chain found in the molecule.
Immunofluorescence can be used on tissue
sections, cultured cell lines, or individual cells,
and may be used to analyze the distribution of
proteins, glycans, and small biological and non-
biological molecules. This technique can even be
used to visualize structures such as intermediate-
sized filaments.

80. Differentiate between viable
count and total count
Define immunization
Define antigen
Immunization is the administration of antigenic
solution, usually orally or via injection, to protect
against infectious bacterial and viral diseases.
(AN-tih-jen) Any substance that causes the body to make an immune response
against that substance. Antigens include toxins, chemicals, bacteria, viruses, or
other substances that come from outside the body. Body tissues and cells, including
cancer cells, also have antigens on them that can cause an immune response.