The document discusses infection control principles including microorganisms, pathogens, infection transmission, and the nurse's role in controlling infections. It describes the chain of infection which involves an infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. Breaking the chain of infection is key to preventing the spread of disease. Nurses play an important role in controlling infections through proper hygiene, asepsis, and following universal precautions.

1. Infection Control
In Clinical Setting:
Mrs. Babitha K Devu

2. The very first
requirement in
a hospital is
that it should do
the sick no
harm
Mrs. Babitha K Devu 2

3. Learning Objectives:
• Identify the nature of infection
• Describes the chain of infection transmission
• State the stages of infectious process
• Discuss the defenses against infection : natural
and acquired
• Enumerate the role of healthcare personnel
and health agencies in infection control
Mrs. Babitha K Devu 3

4. Introduction:
Current trends, public awareness, and rising costs of
health care have increased the importance of
infection prevention and control. Increases in drug-
resistant microorganisms and concern about
occupational exposure to tuberculosis (TB), human
immune deficiency virus (HIV), and hepatitis have
increased concern about transmission of infections.
Regardless of where they practice, preventing the
transmission of microorganisms is a concern of all
nurses. One way that nurses accomplish this goal is
by asepsis.
Mrs. Babitha K Devu 4

5. Introduction:
This chapter discusses the infection control
principles including naturally occurring
microorganisms, pathogens, infection and
colonization, chain of infection, body
defenses, stages of the infectious process
and nurse’s role in controlling infections.
Mrs. Babitha K Devu 5

6. • Microorganisms are capable of harming people.
• Since pathogenic microorganisms cause
contamination, infection and decay, it becomes
necessary to remove or destroy them from
materials and areas.
• This is the objective of infection control and
sterilization.
6
INTRODUCTION
Mrs. Babitha K Devu

7. INFECTION
• Definition: Injurious contamination of body or
parts of the body by bacteria, viruses, fungi,
protozoa and rickettsia or by the toxin that they
may produce.
 Infection may be local or generalized and spread
throughout the body.
 Once the infectious agent enters the host it begins
to proliferate and reacts with the defense
mechanisms of the body producing infection
symptoms and signs: pain, swelling, redness,
functional disorders, rise in temperature and pulse
rate and leukocytosis.
Mrs. Babitha K Devu 7

8. • INFECTION CONTROL – Also called “exposure control
plan” by Occupational Safety & Health
Administration is a required office program that is
designed to protect personnel against risks of
exposure to infection.
• EXPOSURE – is defined as specific eye, mouth, other
mucous membrane, non intact skin, or parenteral
contact with blood or other potentially infectious
materials.
8
Terminologies:
Mrs. Babitha K Devu

9. • UNIVERAL PRECAUTIONS - means that all
patients and blood contaminated body fluids are
treated as infectious.
• PERSONAL PROTECTIVE EQUIPMENT (PPE) – is a
term used for barriers, such as gloves, gown, or
mask.
9Mrs. Babitha K Devu
Terminologies:

10.  STERILIZATION: Use of a physical or chemical
procedure to destroy all microorganisms including
substantial numbers of resistant bacterial spores.
 Sterilization means the destruction of all life forms.
(Ronald B Luftig)
 Sterilization is the process of killing or removing all
viable organisms. (MIMS – PLAYFAIR)
 STERILE: Free from all living microorganisms; usually
described as a probability (e.g., the probability of a
surviving microorganism being 1 in 1 million)
10Mrs. Babitha K Devu
Terminologies:

11. 11Mrs. Babitha K Devu
Terminologies:
•DISINFECTION: Destruction of pathogenic and other
kinds of microorganisms by physical or chemical
means.
•Disinfection is less lethal than sterilization, because it
destroys the majority of recognized pathogenic
microorganisms, but not necessarily all microbial forms
(e.g., bacterial spores).
•Disinfection is a process of removing or killing most,
but not all, viable organisms.(MIMS-PLAYFAIR).
•Disinfection refers to the destruction of pathogenic
organisms.(Ronald B Luftig).

12. • DISINFECTANT: A chemical agent used on inanimate
objects to destroy virtually all recognized pathogenic
microorganisms, but not necessarily all microbial
forms (e.g., bacterial endospores).
12Mrs. Babitha K Devu
Terminologies:

13. Nature Of Infection:
• An infection is the invasion of a susceptible
host (e.g. a patient) by potentially harmful
microorganisms (pathogens), resulting in
disease. The principal infecting agents are
bacteria, viruses, fungi and protozoa.
• Colonization is the presence and growth of
microorganisms within the host but without
tissue invasion or damage.
(Tweeten, 2005)
Mrs. Babitha K Devu 13

14. Nature Of Infection:
• All persons have microorganisms on their skin,
but usually no disease results.
• Disease or infection results only if the
pathogens grows or multiply and alter normal
tissue function.
• An infectious disease transmitted directly
from one person to another is considered a
contagious or communicable disease.
Mrs. Babitha K Devu 14

15. Mrs. Babitha K Devu 15
Facts about microorganisms
• Not all are harmful
• Normal flora or resident flora (microorganisms)
are found on skin, in the intestines and vagina
• Some are necessary to maintain normal bodily
functions
– Escherichia coli (E. coli):
• Aids the digestive process in the colon
• Can cause infection in the blood or urine;
can cause spontaneous abortion

16. Mrs. Babitha K Devu 16
Facts about microorganisms
• Some microorganisms are part of the normal flora
but have no beneficial role
• Normally they do no harm unless the person is
susceptible to infection due to suppression of the
body’s immune response
• The immune response: the body fights infection by
producing antibodies (protective proteins that
combat pathogens)
• Transient Flora are microorganisms that are episodic

17. Mrs. Babitha K Devu 17
Facts about microorganisms
• Pathogens are disease producing microorganisms
• Pathogenicity refers to the ability of a microorganism to
produce disease.
• Virulence refers to the frequency, with which a pathogen
causes diseases. Or vigor with which the organism can
grow and multiply.
• Invasiveness describes the organism’s ability to enter
tissue
• Specificity refers to the organism’s attraction to a specific
host.
• Opportunistic infections take advantage of the body’s
weakened state to grow

18. Mrs. Babitha K Devu 18
Growth of microorganisms
• Aerobic – require oxygen to live
• Anerobic – do not require oxygen to live
• Many microorganisms thrive in warm, moist, dark
environments like the human body which becomes
a host to the microorganism
• Symbiosis – the host benefits
• Neutralism – no damage is done to the host
• Parasitic – the host is damaged, the pathogen
causing damage is called the parasite

19. Mrs. Babitha K Devu 19
Types of microbes
• Microbe – a pathogenic microorganism
• Classifications of plant and animal microbes:
– Bacteria
– Viruses
– Fungi
– Rickettsia
– Protozoa

20. Mrs. Babitha K Devu 20
Types of microbes

21. Chain of Infection/Infection Process:
Pathogen/
Agent
Mode
of
Transmissi
on
Portal of
Entry
Why Isolation?.. because transmission is easier to
control than the source / host!Mrs. Babitha K Devu 21
Reservoir
Portal of
Exit
Susceptibl
e Host

22. Chain of Infection/Infection Process:
Mrs. Babitha K Devu 22

23. Chain of Infection/Infection Process:
•The life cycle of pathogens is frequently described as
an uninterrupted chain of events. For microorganisms
to spread disease, they must grow, reproduce, and
move from one source to another.
•The chain of infection includes the infectious agent,
the source, the portal of exit, the mode of
transmission, the portal of entry, and a susceptible
host.
•Infection develops if the links in this chain remain
intact. Preventing infection includes breaking the chain
of infection.
Mrs. Babitha K Devu 23

24. Infectious Agent
Infectious Agent/
Pathogens
Bacteria
Virus
Fungus
Rickettsia
Protozoa
Parasites
Mrs. Babitha K Devu 24

25. Infectious Agent
• The first link in the chain of infection is the
microbial agent or pathogens. The ability of
the infectious agent to cause disease depends
on its Pathogenicity, virulence, invasiveness,
and specificity.
• The more pathogenic, virulent, and invasive
the organism, the more likely it can overcome
normal body defenses, causing an infection.
• These four characteristics are determined by
the structure or chemical composition of the
microorganism.
Mrs. Babitha K Devu 25

26. Source/Reservoir
• A reservoir is organism or place where
microorganisms survive, multiply, and wait to
transfer to a susceptible host. These are elements in
the environment.
• A source is any place from which an infectious agent
passes or disseminated to the host.
Mrs. Babitha K Devu 26
Sources/
Reservoirs

27. Source/Reservoir
It includes medications, air, food,
water, or any other material on
which organisms can find
nourishment and survive.
It include other patients, health care
personnel, family members, visitors,
and patients themselves.
Animals are often sources of
disease for human beings. Insect
and rats are good examples.
Mrs. Babitha K Devu 27

28. Portal of Exit
• Portal of exit provides a means for the
microorganism to leave the source.
Mrs. Babitha K Devu 28
, vomitus

29. Mode Of Transmission
• It refers to the way in which the organism moves or is
carried from the source’s to portal of exit.
Mrs. Babitha K Devu 29

30. MODES OF TRANSMISSION
There are five main modes or routes of transmission
• Contact
• Vector borne
• Air borne
• Droplet
• Common vehicle
30Mrs. Babitha K Devu

31. DROPLET TRANSMISSION
Droplet generated by sneezing
Coughing or respiratory tract
procedures like Broncoscopy or
suction
VECTOR TRANSMISSION
Transmitted through insects and
Other invertebrates animals
such as mosquitoes and fleas.
31Mrs. Babitha K Devu

32. VECTOR TRANSMISSION
Vectors can be biologic or mechanical.
Biological vectors are living creatures that
carry pathogens, such as rats, insects, or
birds.
Biological vector borne transmission is
further classified into:
Propagative: in this mode pathogens will
multiply but no growth
Cyclo-developmental: in this mode
pathogens will grow but no multiplication
Cyclo-propagative: in this mode pathogens
will multiply as well as grow
32Mrs. Babitha K Devu

33. VECTOR TRANSMISSION
Vectors can be biologic or mechanical.
Biological vectors are living creatures
that carry pathogens, such as rats,
insects, or birds.
Mechanical vectors are inanimate
objects that are contaminated with
infected body fluids like central line
catheter, needles and syringes shared
by IV drugs users.
33Mrs. Babitha K Devu

34. AIR BORNE TRANSMISSION
Tiny droplet nuclei that remain (<5)
suspended in air.
COMMON VEHICLE TRANSMISSION
Transmitted indirectly by materials
contaminated with the infections.
e.g. foods can carry Salmonella, blood
can carry Hepatitis and HIV.
34Mrs. Babitha K Devu

35. CONTACT TRANSMISSION
Most important and frequent mode of
transmission of nosocomial infections, is divided
into two subgroups:
• Direct-contact transmission
• Indirect-contact transmission.
Direct-contact transmission
Involves a direct body surface-to-body surface
contact causing the physical transfer of
microorganisms between a susceptible host and
an infected or colonized person, such as occurs
when a person turns a patient, gives a patient a
bath, dressing changes and inserting devices.
35Mrs. Babitha K Devu

36. • Indirect-contact transmission
Involves contact of a susceptible host
with a contaminated intermediate
object, usually inanimate, such as shared
patient care devices, shared pediatric
toys, contaminated instruments, needles,
or dressings, or contaminated gloves
that are not changed between patients
36Mrs. Babitha K Devu

37. Mrs. Babitha K Devu 376) Mucous Membrane

38. Mrs. Babitha K Devu 38
A host is a person whose own body defense mechanisms,
when exposed, cannot withstand the invasion of
pathogens.

39. Stages Of Infection:
There are two types of infections:
• Localized infections: are limited to a defined area
or single organ.
• Systemic infections: affect the entire body and
organs.
All infections progress through four stages:
Incubation
Prodromal
Illness
Convalescent
Mrs. Babitha K Devu 39

40. Stages Of Infection:
All infections progress through four stages:
Incubation: it is the time period between entry of an
infectious agent in the host and the onset of symptoms.
Prodromal: it is the time from the onset of non-specific
symptoms until specific symptoms begin to manifest.
During this period the client is infectious to others.
Illness: is the time, when the client has specific signs
and symptoms of an infectious process.
Convalescent: is from the beginning of the
disappearance of acute symptoms until the client
returns to the previous state of health. Length of
recovery depends on severity of infection.
Mrs. Babitha K Devu 40

41. Defense Against Infection:
The human body has three “lines of defense”
against infectious disease.
1. Certain anatomical features limit the entry of
pathogens.
2. Protective biochemical processes fight
against pathogens.
3. Immune responses.
Mrs. Babitha K Devu 41

42. Immunity
• The term immunity refers to the body’s specific
protective response to an invading foreign agent or
organism.
• The human body has the ability to resist almost all
types of organisms or toxins that tend to damage the
tissues and organs. The capability is called immunity.
42Mrs. Babitha K Devu

43. Types of immunity
1. Natural (Innate) immunity
2. Acquired (adaptive) immunity
43Mrs. Babitha K Devu

44. Natural (Innate immunity)
• The basis of natural defense mechanisms is the
ability to distinguish between friend and foe or self
and non-self.
• Such natural mechanisms include
1. Physical and chemical barriers
– Skin and mucous membrane
– Antimicrobial substance in body secretions
2. The action of WBCs
3. Inflammatory response.
4. Fever
44Mrs. Babitha K Devu

45. Physical and chemical barriers
• When skin and mucous membrane are intact and healthy
they provide a physical barrier to invading microbes.
• Sebum and sweat secreted on to the skin surface contains
antibacterial and antifungal substances.
• Hairs in the nose acts as a coarse filter. Respiratory tree are
covered with mucous membranes that trap pathogens, which
are then expelled. Nasal passages contains cilia that sweeps
microbes upward from the lower airways. Coughing and
sneezing forcefully expel organisms from respiratory tract.
• Simple peristalsis, as well as diarrhoea and vomiting, are first
line defense mechanism against microbes that invade GI
Tract.
• One way flow of urine from the bladder during micturation45Mrs. Babitha K Devu

46. Antimicrobial substance in body secretions
1. Hydrochloric acid in gastric juice
2. Tears contains Lysozomes
3. Saliva and urine also contains lysozyme
4. Immunoglobulin in nasal secretions and saliva
5. Bile has antimicrobial action
6. Highly acidic nature of urine and vagina
46Mrs. Babitha K Devu

47. White blood cell action
• WBCs participate in both the natural and the acquired
immune responses.
• Granulocytes include neutrophils, eosinophils and
basophils are occasionally phagocytic and release
histamine which prompts inflammation.
• Nongranular leucocytes include monocytes or
macrophages and lymphocytes that specialize in cleaning
up sites of injury.
• Lymphocytes consisting of B cells and T cells, play major
role in humoral and cell mediated immune responses.
47Mrs. Babitha K Devu

48. Inflammatory response
• Major function of the natural (non specific or innate)
immune system. This process begins when histamine
and other chemicals are released.
• Chemical mediators assist this response by
minimizing blood loss, walling off the invading
organism, activating phagocytes and promoting
formation of fibrous scar tissue and regeneration of
injured tissue by increasing permeability of blood
vessels, oxygen and nutrients to the damaged area.
48Mrs. Babitha K Devu

49. Inflammatory response
49Mrs. Babitha K Devu

50. Fever
• A rise in core body temperature that increases
metabolism, inhibits multiplication of
pathogens and triggers specific immune
responses.
Mrs. Babitha K Devu 50

51. Acquired immunity
• Usually develops as a result of prior exposure to an
antigen through immunization or by contracting a
disease.
• Weeks or months after exposure to the disease or
vaccine, the body produces an immune response
that is sufficient to defend against the disease upon
re-exposure to it.
51Mrs. Babitha K Devu

52. Active and passive immunity
1. Active immunity: Active immunity means that the
individual has responded to an antigen and produced
his own antibodies, lymphocytes are activated and the
memory cells formed provide long lasting resistance.
2. Passive immunity: In passive immunity the individual is
given antibodies produced by someone else
52Mrs. Babitha K Devu

53. Acquired immunity
• The cells involved in acquired immunity are WBCs
called lymphocytes. There are two types of
lymphocytes namely B cells and T cells.
Lymphocytes recognize foreign substances by the
molecules that they are present on their surfaces.
These molecules trigger a specific immune
response called antigens to target for destruction.
• B cells are involved in the humoral immunity and
T cells are responsible for cell-mediated
immunity.
Mrs. Babitha K Devu 53

54. Acquired immunity
• Humoral Immunity: it acts directly against
antigens. In response to the presence of
antigens, macrophages and a class of T cells
called helper T cells, stimulate B cells to
become plasma cells and produce antibodies
called immunoglobulin's (Ig). Antibodies are
proteins which bind to target antigens and
destroy them by any of the following
methods:
Mrs. Babitha K Devu 54

55. Acquired immunity
• Humoral Immunity:
 Phagocytosis
 Neutralization
 Agglutination
 Activation of complement and inflammation
Mrs. Babitha K Devu 55

56. Acquired immunity
• Cell-mediated Immunity:
The humoral immune response acts directly against
antigenic cells, the cell-mediated immune
response acts to destroy body cells that have
become infected. Four types of T cells are:
Cytotoxic (killer) T cells
Helper T cells
Memory T cells
Suppressor T cells
Mrs. Babitha K Devu 56

57. Role of the nurse In Infection Control
The role and responsibilities of the nurses in infection control
are as follows:
• Providing staff education on infection control
• Reviewing infection control policies and procedures
• Reviewing client medical and lab records to recommend
appropriate isolation procedures
• Screening client record for community acquired infection
• Consulting with employer health departments concerning
recommendation, to prevent and control the spread of
infections among personnel's
• Gathering statistics regarding HAI
• Notify public health department of incidence of
communicable diseases
• Educating clients and family
• Identifying infection control problems with equipmentsMrs. Babitha K Devu 57

58. Mrs. Babitha K Devu 58