3. Definition of Normal Flora
• Population of microorganisms
that inhabit the skin of mucous
membranes of healthy normal
persons
• Also referred to as indigenous
species or indigenous
microbiota
Actinomyces israelii, part of the normal
flora of the oral cavity.
5. RESIDENT FLORA
• Fixed types of microorganisms regularly
found in a given area at a given age
• If disturbed, it promptly reestablishes itself/
transient microorganisms may colonize,
proliferate and produce disease
• More important
6. TRANSIENT FLORA
• Non-pathogenic or potentially pathogenic
microorganisms that inhabit the skin or
mucous membranes for hours, days, or
weeks
• Derived from the environment, does not
produce disease
• Does not establish itself permanently on
the surface
• Little significance
7. ROLES
1. Protective host defense by
maintaining conditions such
as pH so other organisms
may not grow
2. Synthesize vitamin K and B
8. Where the Normal Flora Are Found
• Skin
• Conjunctiva
• Nasopharynx
• Oral cavity
• Gastrointestinal tract
and rectum
• Urogenital tract
13. NORMAL FLORA- Skin
SITE COMMON/ LESS COMMON BUT
MEDICALLY NOTABLE
IMPORTANT ORGANISMS
ORGANISMS
Cutaneous surfaces Staphyloccocus Staphyloccocus aureus,
including urethra and epidermidis Corynebacteria
outer ear (diphteroids)
Streptococci,
Anaerobes e.g.
Peptostreptococci,
Yeast (Candida sp.)
Staphylococcus epidermidis, invariably
found on skin and nasal membranes.
14. Factors that are Important in Eliminating
Non-resident microorganism from the Skin
1. Low pH
2. Fatty acids (sebaceous secretions)
3. Lysozyme
Neither profuse sweating nor
washing and bathing can eliminate
or significantly modify the normal
resident flora
15. Normal flora of the skin:
staphylococci, corynebacteria
Benefit Harm
• Inhibit fungal growth Body odor
(athlete’s foot) Acne
• Body odor Opportunistic
infections
16. Normal flora –
UPPER RESPIRATORY TRACT
SITE COMMON/ LESS COMMON BUT
MEDICALLY NOTABLE
IMPORTANT ORGANISMS
ORGANISMS
NOSE Staphyloccocus aureus Staphyloccocus
epidermidis,
Corynebacteria
(diphteroids)
Assorted Streptococci,
Oropharynx Viridans streptococci Assorted streptococci,
including Streptococcus nonpathogenic
mutans Neisseria, nontypeable
Haemophilus influenzae
17. Normal flora- Oropharynx
• Normally sterile at birth but maybe
contaminated by passage through the birth
canal
• Within 4-12 hours after birth, viridans stre
become established as the most
prominent members of the resident flora
and remains so for life
18. Normal flora- Oropharynx
• If large numbers are introduced into the
bloodstream (following tooth extraction or
tonsillectomy) they may settle on
deformed/
prosthetic heart valves and produce
endocarditis
• Aspiration of saliva (containing 1012 of these
organism and aerobes) ma result in
necrotizing pneumonia, lung abscess, and
empyema
19. Normal flora of the oral cavity:
streptococci and lactic acid bacteria
Benefit Harm
• Compete with • Plaque formation
pathogens for and dental disease
colonization sites
• Produce substances
that inhibit
pathogens
• Stimulate local
immunity
20. Normal Flora
SITE COMMON/ LESS COMMON BUT
MEDICALLY NOTABLE
IMPORTANT ORGANISMS
ORGANISMS
Gingival crevices Anaerobes, Prevotella,
Fusobacterium,
Streptococcus,
Actinomyces
Stomach NONE Acidity keeps the number
of microorganisms at
minimum 103-105 unless
obstruction at the pylorus
favors the proliferation of
gram-positive cocci and
bacilli
21. Normal flora of GI tract - stomach
Helicobacter pylori
Harm
• Causes gastric
ulcers
• Probable
Helicbacter pylori
association with
duodenal ulcers
22. Normal Flora- COLON
SITE COMMON/ LESS COMMON BUT
MEDICALLY NOTABLE
IMPORTANT ORGANISMS
ORGANISMS
Colon INFANTS Lactobacillus,
(microaeropjilic/ Breast-fed: Streptococci,
anaerobic) Bifidobacterium Eubacterim,
Bottle-fed: Fusobacterium,
**sterile at birth, but mixed flora, less Lactobacillus, assorted
organisms are soon lactobacilli gram-negative
introduced with food ADULTS Anaerobic rods,
Bacteroides Enteroccocus faecalis
(predominant) and other streptococcus
Escherochia
Bifidobacterium
23. Normal flora of GI tract: SMALL INTESTINE
streptococci, lactobacilli, enterococci, enterics,
anaerobic rods and cocci
Benefit Harm
• Production of • Possible relationship with
vitamins and inflammatory conditions
nutrients • Transfer antibiotic
• Competition with resistance to pathogens
pathogens for
colonization sites
• Production of
substances that
inhibit pathogens
24. Normal flora of GI tract: LARGE INTESTINE
Bacteroids, clostridia, bifidobacteria, lactic acid
bacteria, enterococci, enterics
Benefit Harm
• Competition with • Relationship with
pathogens for inflammatory bowel
colonization sites diseases
• Production of • Production of
substances that carcinogens and
inhibit pathogens relationship with colon
• Stimulate cancer
development and • Methanogenesis
activity of immune
system
25. Normal flora of the VAGINA -
during child-bearing years: lactobacilli and other
lactic acid bacteria
Benefit Harm
• Competition with • none
pathogens for
colonization sites
• Production of lactic
acid that inhibits
pathogenic bacteria
and yeasts
26. Overall benefits of the normal flora
Synthesis and excretion of vitamins used by
the host
Competition with pathogens for nutrients and
colonization sites
Direct antagonism against pathogens
Stimulate the development of immunological
tissues
Stimulate the activity of the immune system
by production of natural antibodies
27. Overall harmful effects of the normal flora
• Competition with host for nutrients
• Bacterial synergism between normal flora and
potential pathogens
• Low grade toxemia produced in host
• Endogenous disease and opportunistic
infection
29. Defense Mechanisms
• A number of defense mechanisms
exist outside and in the body to
break the chain, including
decreasing the sources of
microorganisms; preventing the
transmission of microorganisms;
and maximizing the host’s
resistance to the microorganism
30. Body’s natural defenses to
eliminate/kill pathogens
• Cilia - in respiratory tract, catch and move
pathogens out of the body
• Coughing/sneezing, to propel pathogens
outward
• Tears - contain chemicals to kill bacteria
• Hydrochloric acid in stomach
• Rise in body temperature (fever)
• Leukocyte (white blood cell) production
increases, to destroy pathogens
32. Chain of infection
• Model of infectious disease transmission
• Six elements must be present for an infection to
develop
1. The infectious agent
2. Reservoir host
3. Portal of exit from the host
4. Route of transmission
5. Port of entry
6. Susceptible host
33. Chain of infection
Infectious
agent
Susceptible Reservoir
host Host
Portal of
entry Portal of
exit
Route of
transmission
34. Chain of infection
1. Infectious agent: a pathogen must be
present
2. Reservoir host: the pathogen must have a
place to live and grow – the human body,
contaminated water or food, animals,
insects, birds, dead or decaying organic
material.
• Humans who can transmit infection but
how no signs of the disease are called
carriers. Person may be unaware they are
a carrier.
35. Chain of infection
3. Portal of exit: the pathogen must
be able to escape from the
reservoir host where it has been
growing.
• Examples of portals of exit are
blood, urine, feces, breaks in the
skin, wound drainage, and body
secretions like saliva, mucus and
reproductive fluids
36. Chain of infection
4. Route of transmission: When the
pathogen leaves the reservoir
host through the portal of exit, it
must have a way of being
transmitted to a new host.
• Examples of routes of
transmission are air, food,
insects, and direct contact with
an infected person
37. Chain of infection
5. Portal of entry: The pathogen must
have a way of entering the new host.
Common ports of entry are the mouth,
nostrils, and breaks in the skin
6. Susceptible host: An individual who
has a large number of pathogens
invading the body or does not have
adequate resistance to the invading
pathogen will get the infectious
disease
38. Breaking the chain of infection
• Breaking at least one link stops the
spread of infectious disease
1. The infectious agent
• early recognition of signs of infection
• Rapid, accurate identification of organisms
2. Reservoir host
• Medical asepsis
• Standard precautions
• Good employee health
• Environmental sanitation
• Disinfectant/sterilization
39. Breaking the chain of infection
3. Portal of exit from the host
• Medical asepsis
• Personal protective equipment
• handwashing
• Control of excretions and secretions
• Trash and waste disposal
• Standard precautions
40. Breaking the chain of infection
4. Route of transmission
• Standard precautions
• Handwashing
• Sterilization
• Medical asepsis
• Air flow control
• Food handling
• Transmission-based precautions
41. Breaking the chain of infection
5. Portal of entry
• Wound care
• Catheter care
• Medical asepsis
• Standard precautions
5. Susceptible Host
• Treating underlying diseases
• Recognizing high-risk patients
42. Stages of Infectious Process
• Incubation period
– period begins with active replication
but with no symptoms
• Prodromal stage
– Symptoms first appear
• Acute phase
– proliferation and dissemination of
pathogens
43. Stages of Infectious Process
(CONT)
• Convalescent stage
- containment of infection and
pathogens are eliminated
• Resolution
– total elimination of pathogens
without residual manifestation
Nosocomial infection
– Infection acquired in a health care
setting.
– Typically manifest after 48 hrs.
– UTI most common type
44. FACTORS AFFECTING RISK
OF INFECTION
• AGE
• HEREDITY
• LEVEL OF STRESS
• NUTRITIONAL STATUS
• CURRENT MEDICAL THERAPY
• PRE-EXISTING DISEASE
• IMMUNIZATION STATUS
45. Standard precautions
• Blood
• All body fluids, secretions, excretions,
• Non-intact skin
• Mucous membranes
• Essential elements:
• Use barrier protection
• Prevent inadvertent percutaneous
exposure, dispose of needles
• Immediate and thorough hand washing
47. Infection control
• Goal of infection control is to
prevent the spread of infectious
diseases
• Infectious disease is any disease
caused by the growth of pathogens
in the body
• Pathogens are disease-causing
microorganisms (germs)
• Infectious diseases can cause
unnecessary pain, suffering and
death
48. Maintain a safe environment
• Follow specific polices and
procedures designed to reduce risk
of transferring infectious diseases
• Prevent pathogens from being
transmitted:
• Patient to client, staff to client, client to
staff, staff to staff
• Improperly cleaned instruments and
equipment
49. Infection
Infection can be:
• Generalized or systemic (throughout the
body)
• Localized (affecting one part of the body)
Signs and symptoms of infection:
• Systemic: headaches, fever, fatigue,
vomiting, diarrhea, increased pulse and
respiration
• Localized: redness, swelling, painful,
warm to the touch
50. Infection Control in In-Patient
Health Care Agencies
• Hand Hygiene
• Patient Placement
• Protective Equipment
• Proper disposal of Soiled Equipment
51. Infection Control In Community –
Based Setting
• Sanitation
• Proper Disposal of Waste
• Food Preparation
• Report CD Occurrence
52. Scope of the problem
• Health care facilities or “sick care
buildings” have higher concentration
of microorganisms than a normal
environment
• Patients with lowered levels of resistance
due to illness
• Health care personnel have frequent
contact with body fluids
• Nosocomial infection – contracted by
5-10% of patients while receiving
health care
• Results in 80,000 deaths per year
53. Scope of the problem
• Industrial illness – a disease contracted
by a health care professional during work
• Blood-borne pathogens such as Hepatitis
B and HIV can be transmitted through
needle sticks
• 800,000 needle sticks occur each year
• Up to 500 health care workers die each
year from Hepatitis B
• Follow precautions when performing
procedures
• Dispose of all sharps in proper containers
54. Regulatory Agencies
• Center for Disease Control and
Prevention (CDC) - Responsible for
developing safe guidelines to help
prevent and control the spread of
infectious diseases
• Occupational Safety and Health
Administration (OSHA) - Responsible
for maintaining minimum health and
safety standards for employees
55. Prevention: Medical Asepsis
• Medical asepsis (clean technique):
procedures to decrease the number
and spread of pathogens
• Hand washing, good personal
hygiene, cleaning rooms between
patient use, proper disposal of
gloves after contact with body fluids
or contaminated objects
56. Prevention: Surgical Asepsis
• Surgical asepsis (sterile technique):
procedures that completely eliminate
the presence of pathogens from
objects and areas
• Sterile caps, gowns, masks, and gloves
• Sterilizing instruments
• Maintaining sterile fields
• Changing dressing
• Disposing of contaminated materials
57. Breaking chain of infection
• Most important concept: breaking
at least one link stops the
infectious disease
• Chain of infection summarized into
3 components:
1. Source of infecting microorganisms (1
& 2)
2. Means of transmission for the micro-
organisms (3, 4 & 5)
3. Susceptible host (6)
58. Breaking chain of infection
Best defenses:
1. Decrease the sources of infecting
microorganisms (1 & 2)
2. Prevent means of transmission for the
micro-organisms (3, 4 & 5)
3. Maximize the resistance of the host (6)
59. Methods to decrease the source
of microorganisms
• Perform proper hand washing
• Decontaminate surfaces and
equipment with antiseptics,
disinfectants and sterilization
procedures
• Avoid contact with patients and
others when harboring infectious
microorganisms
60. Preventing transmission of
microorganisms
• Wear PPE – personal protective
equipment: caps, gloves, gowns
masks, booties and eye protection
• Follow isolation procedures when
indicated
• Take additional precautions when
working with patients who have
highly contagious diseases. Don’t
ignore posted signs.
61. Maintaining resistance
• Provide and practice good hygiene
• Ensure proper nutrition and fluid
intake
• Get enough rest
• Decrease stressors – physical and
psychosocial - that weaken the
immune response
• What can you do in your life to
increase resistance to disease-
causing pathogens?
62. Standard Precautions
• Developed by the CDC
• Follow at all times and apply to
every patient
• To prevent contact with potentially
infectious body fluids: blood,
secretions, excretions, non-intact
skin and mucous membranes
63. Handwashing
• Perform proper handwashing
techniques:
• when coming on the clinical site
• when taking a break or leaving work
• between client contacts
• before gloving and after ungloving
• before and after touching your face
• after contact with any contaminants
• before touching items considered clean
64. Handwashing
Procedure – step-by-step how to do it
• Explain why is it important to know
(1) the procedure – what to do
(2) the rationale – the reason you do it
that way, why each step is important
65. Personal Protective Equipment
• Abbreviated PPE
• Includes gloves, masks, protective
eyewear, gowns, caps and shoes
• Use appropriate PPE in situations that
could cause infection to you or your
client
• Use clean, non-sterile gloves when
handling blood, body fluids, secretions,
excretions, contaminated items, mucous
membranes and non-intact skin
66. Gloves
• Change gloves between
tasks/procedures on the same client if
there is contact with material that may
contain a high concentration of
microorganisms (ex: feces)
• Remove gloves promptly after use,
before touching non-contaminated
items and environmental surfaces and
before taking care of another patient
• After removing gloves, wash your
hands
67. Face Protection
• Face protection: Mask, Eye Protection
and Face Shield
• Hospital workers wear a mask and eye
protection or a face shield to protect
mucous membranes of the eyes, nose
and mouth during procedures that
could involve splashes or sprays of
blood, body fluids, secretions or
excretions.
68. Gowns
• Gowns may be cloth or paper
• Cloth gowns are reusable
• Paper gowns are disposable
• Some clinical sites provide gowns to
clients for physical exams
• A clean, non-sterile gown protects skin
and prevents soiling clothing during
procedures that could involve splashes
or sprays of blood, body fluids,
secretions or excretions.
• Follow the procedures on your clinical
site(s)
69. Removing a Gown
• Remove a soiled gown as promptly as
possible
• Fold front of gown into itself, outside in
• Place cloth gowns in a closed
receptacle marked with the biohazard
symbol to be picked up, laundered and
re-used
• Place paper gowns in a closed waste
can in a red plastic bag marked with the
biohazard symbol
• Wash hands promptly to avoid
transferring microorganisms
70. Client care equipment
• Handle used/soiled client care equipment
to prevent skin, mucous membranes and
clothing from exposure to blood, body
fluids, secretions and excretions which
could be transferred to other patients and
environments
• Reusable equipment must be properly
cleaned and reprocessed before being
used on another client
• Discard single-use items appropriately
71. Environmental Control
• Follow procedures for the routine care,
cleaning and disinfection of
environmental surfaces, beds, bedside
equipment, and other frequently
touched surfaces
• For used linen that is soiled with blood,
body fluids, secretions and excretions –
fold with soiled surface in, handle to
prevent exposing skin, mucous
membranes and clothing which could
transfer microorganisms to other
environments, and place in designated
biohazardous medical waste receptacle
72. Occupational Health and
Blood-Borne Pathogens
• Take care to prevent injuries when
using and cleaning/disposing of
“sharps” - needles, scalpels, and other
sharp instruments
• Place used disposable syringes,
needles and scalpel blades in
appropriate puncture-resistant
containers
• Containers should be located close by
for convenient disposal
• Placer reusable syringes and needles in
a puncture resistant container for
transport to be reprocessed (sterilized)
73. Occupational Health and
Blood-Borne Pathogens
• Never recap used needles
• Follow facility policies on how to handle
contaminated needles
• If the facility allows recapping (for
example, drawing up from a multi-dose
vial), use either a one-handed “scoop”
technique or a mechanical device to
hold the needle sheath
• Do not remove used needles from
disposable syringes by hand
• Do not bend, break or manipulate used
needles
74. Occupational Health and
Blood-Borne Pathogens
• Use mouthpieces, resuscitation
bags, or other ventilation devices
as an alternative to mouth-to-
mouth resuscitation methods.
• Keep these devices available in
areas where clients may need to
be resuscitated (ie, birth rooms)
76. Using a flow inflating
resuscitation bag on a baby
77. Environmental control
• Follow facility infection control
procedures for cleaning the environment,
jacuzzi tubs, etc.
• Use Transmission-Based Precautions:
• Airborne precautions
• Droplet precautions
• Contact precautions
78. Airborne Precautions
• Airborne droplets or dust particles
containing infectious agents can
remain suspended in the air for long
periods of time
• Air currents can blow them long
distances
• Can be emitted during talking,
sneezing, coughing and whispering
• Examples: Mycobaterium tuberculosis,
Rubeola (measles) and Varicella
(chicken pox)
79. Droplet Precautions
• Propelled short distances through the air
• Deposited on host’s conjunctiva, nasal
mucosa or mouth
• Can be emitted during talking, sneezing,
coughing and during procedures like
suctioning and bronchoscopy
• Examples: streptococcal pharyngitis,
mumps, influenza, rubella, some some
pneumonias, meningitis and sepsis
80. Contact Precautions
• Most important and frequent mode of
transmission for nosocomial infections
• Nosocomial = originates/takes place in
hospital or other health care facility
• Nosocomial infection = the client gets it as a
result of being in the health care facility
• Example: herpes (HSV), impetigo,
scabies, some gastrointestinal,
respiratory, skin and wound infections
• Direct-contact & Indirect-contact
transmission
81. Direct Contact Indirect contact
Transmission transmission
• Occurs when touching • Occurs when a
the infected client’s dry contaminated object
skin during client care is touched.
activities like giving a • For example,
massage coming in contact
• Can occur between two with needles,
clients: a source of the instruments,
infecting micro-organism environmental
and a susceptible host surfaces or client
care items.
82. Double-bagging technique
• Used when disposing of medical waste
from clients with infections (ex HIV)
• Health care worker “A”, wearing proper
PPE, takes the contaminated bag from
the area
• “A” slips it into another bag held by co-
worker “B”
• “B” does not touch the contaminated bag
• “A” does not touch the clean bag
• The bags are labeled according to the
facility policy with hazardous waste or
linen markers to alert to the need for
special handling
83. Sterilization
• Chemical agents and physical
methods used to destroy or inhibit
growth of pathogens
• Bacteriostatic – inhibits growth
• Bacteriocidal/germicidal – kills
microorganisms
• Antiseptics – bacteriostatic chemical
agents, mild enough to use on skin:
70% isopropyl alcohol
• Disinfectants – destroy most bacteria
and viruses. Used for instruments
that do not penetrate the skin and for
cleaning the environment – floors,
bathrooms, equipment
84. Disinfectants
• Chemical disinfectants can be harmful
to the skin. When using chemical
disinfectants follow manufacturer’s
directions for dilution and for antidoting
any exposure
• 10% household bleach in water meets
OSHA requirements, kills HBV, HIV and
TB
• Soaking for 20-30 minutes in 70%
isopropyl alcohol acts as a disinfectant:
used for some instruments, glass
thermometers
• Boiling instruments in water: cover and
boil in “rolling water” for 20 mins. Rarely
used today.
85. Sterilization
• Agents/methods that totally destroy all
microorganisms including viruses and
spores
• Include chemical agents, gas,
radiation, dry or moist heat under
pressure
• Most common method used is the
autoclave, which sterilizes by steam
created by a pressurized heating
system
• Small units used in a medical office;
large units used in hospitals
86. Surgical Asepsis – Sterile Technique
• Aseptic: free from pathogenic
microorganisms
• Sterile Technique: refers to a group pf
principles and procedures designed to
eliminate pathogens
• Sterile field: an area designated as free
from microorganisms
• Example: a sterile towel placed on a
clean, dry surface – the towel becomes
the sterile field
• Consider the field as a 3-dimensional
area
87. Maintaining a sterile field
• Field should be above the waist height
• Do not bring contaminants into the field
• Actions that contaminate the field:
touching it, allowing it to become wet,
reaching across it, talking or coughing
directly over the surface
• Work to the side of the field
• Sterile gloves come in sealed packages
that must be opened at the edge of the
sterile field and placed onto the field.
