NOSOCOMIAL INFECTION OR HOSPITAL ACQUIRED INFECTION OR HEALTHCARE ASSOCIATED INTECTION CAN BE DEFINED AS THE INFECTION ACQUIRED IN THE HOSPITAL BY A PATIENT: WHO WAS ADMITTED FOR A REASON OTHER THAT INFECTION FACTORS AFFECTING HAIS SOURCES OF INFECTION MICRORGANISMS RESPONSIBLE FOR INFECTION TYPES OF HAIS MODE OF TRANSMISSION PREVENTION OF HAIS

1. NOSOCOMIAL
INFECTIONS
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2.  Definition
 Hospital acquired infections or nosocomial infections or
healthcare-associated infections (HAis) can be defined as the
infections acquired in the hospital by a patient:
 who was admitted for a reason other than that infection
 In whom the infection was not present or incubating at the
time of admission
 Symptoms should appear at least after 48 hours after
admission
 This include infections acquired in the hospital but appearing
after discharge, and also occupational infections among staff
of the hospital care facility
HOSPITAL ACQUIRED INFECTIONS (HAIS)
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3.  The principal factors that determine the likelihood that a given
patient would acquire a nosocomial infection are:
 Immune status: Most admitted patients have impaired immunity
either as a part of their preexisting disease processes or, in
some instances, due to the treatment they have received in the
hospital.
 Hospital environment: the hospital environment harbors a
greater magnitude of microorganisms than that of community.
Transmission of these organisms to the patients can cause
nosocomial outbreaks of infection.
FACTORS AFFECTING HAIS
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4.  Hospital organisms: Most of the organisms present in the
hospital environment are multidrug resistant. this is because
of the increased antibiotic usage in the hospital.
 the minor population of resistant organisms present initially
flourish in presence of constant antibiotic pressure and slowly
replace the susceptible strains in die hospital.
FACTORS AFFECTING HAIS
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5.  Diagnostic or therapeutic interventions such as insertion of
intravenous or urinary catheters, or endotracheal tube, may
introduce infection in susceptible patients; most of which are
due to the patient's endogenous flora
 Transfusion: Blood, blood products and intravenous fluids
used for transfusion, if not properly screened, can transmit
many blood borne infections (BBI) such as HIV, Hepatitis B
and C viruses.
 Poor hospital administration: Strong administrative support is
essential to control the Hals; failing of which promote the
spread of HAls.
FACTORS AFFECTING HAIS
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6.  Endogenous Source
 The majority of nosocomial infections are endogenous in
origin, i.e. they involve patient's own microbial flora which
may invade the patient's body during some surgical or
instrumental manipulations.
 Exogenous Source
 Exogenous sources are from hospital environment, staff, or
patients.
SOURCES OF INFECTION
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7.  Environmental sources include inanimate objects, air, water
and food in the hospital.
 Inanimate objects in the hospital are medical equipment's
(endoscopes, catheters, etc.), bed pans, surfaces
contaminated by patients' excretions, blood and body fluid.
 Healthcare workers may be potential carriers, harboring many
organisms; which may be multidrug resistant, e.g. nasal
carriers of Methicillin-resistant Staphylococcus aureus
(MRSA).
 Other patients of the hospital may also be the source of
infection
SOURCE OF INFECTION
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8.  Hospital acquired infections can be caused by almost any
microorganism, but those that survive in the hospital
environment for long periods and develop resistance to
antimicrobials and disinfectants are particularly important.
 The ESKAPE pathogens: They are responsible for a
substantial percentage of nosocomial infections in the
modern era and represent the vast majority of multidrug
resistant isolates present in a hospital.
 Enterococcus faecium
 Staphylococcus aureus
 Klebsiella pneumoniae
 Acinetobacter baumannii
 Pseudomonas aeruginosa
 Enterobacter species
MICROORGANISMS IMPLICATED IN HAIS
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9.  Other infections that can spread in hospitals include:
 Escherichia coli
 Nosocomially acquired Mycobacterium tuberculosis
 Legionella pneumophila
 Candida albicans
 Clostridium difficile diarrhea
MICROORGANISMS IMPLICATED IN HAIS
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10.  Microorganisms spread in the hospital through several modes
 Contact transmission
 Direct contact: Skin to skin contact and thereby physical
transfer of microorganisms between a susceptible host and an
infected or colonized person (usually healthcare workers,
rarely other patients)
 Indirect contact: this involves contact of a susceptible host
with contaminated inanimate objects such as:
 Dressings, or gloves, instruments (e.g. stethoscope)
 Parenteral transmission through: Needle or sharp prick Injury,
splashes of blood or body fluids or excretions, contaminated saline
flush, .syringes, vials and bags
MODES OF TRANSMISSION
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11.  Inhalation mode
 Droplet transmission: Droplets of >5 µm size can travel for
shorter distance (< 3 feet)
 Droplets generated from the infected person while coughing.
sneezing and talking are propelled for a short distance
through the air and deposited on the host's body.
 This is an important mode of transmission of agents causing
bacterial meningitis, diphtheria, and RSV etc
MODES OF TRANSMISSION
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12.  Inhalation mode
 Airborne transmission: This refers to the airborne droplet
nuclei ( 5 µm size) or dust particles that remain suspended in
the air for long time and can travel longer distance
 This is more efficient mode than droplet transmission.
 Microorganisms transmitted by airborne transmission include
Legionella, Mycobacterium tuberculosis, measles and
varicella-zoster viruses.
MODES OF TRANSMISSION
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13.  Vector borne transmission: Via 'Vectors such as mosquitoes,
flies, etc carrying the microorganisms.
 This is a rare mode of transmission In hospital.
 Common vehicle transmission: such as food, water, devices
and equipment's
MODES OF TRANSMISSION
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14.  In any hospital the four most common HAIs encountered are:
 Urinary tract infections (UTIs) (33%)
 Pneumonia (15%)
 Surgical site infections (15%)
 Blood stream infections ( 13%)
TYPES OF HAIS
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15.  Urinary tract infections account for the majority of HAis.
 Risk factors that predispose patients to acquire a nosocomial
UTI include-
 Advanced age,
 Female gender,
 Severe underlying disease,
 Placement of a urinary catheter.
Organisms: Gram-negative rods cause the majority of hospital acquired
UTIs and E. coli is the number one organism implicated. Gram-positive
bacteria and Candida cause the remainder of the infections.
URINARY TRACT INFECTIONS (UTIS)
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16.  lung infections are the major cause of HAIs after UTI.
 Risk factors to develop nosocomial pneumonia are
 advanced age,
 chronic lung disease,
 aspiration of upper respiratory tract secretions into the lungs,
 semiconscious patient,
 chest surgeries
 mechanical ventilation through intubation of endotracheal tube
(ventilator-associated pneumonia)
 Organisms: Gram-negative rods and S. aureus, account for majority of
infections of the patients from the hospital
PNEUMONIA
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17.  Surgical site infections (SSI) are defined as infections that
develop at the surgical site within 30 days of the surgery.
 Organisms: Surgical site wounds are classified as clean,
clean-contaminated, contaminated or dirty.
 For clean wound: The skin flora of the surgery team or the
environmental organisms are the major pathogens; most
common being S. aureus.
 For other types: The patients endogenous flora (anaerobes
and gram-negative rods) are the common agents.
SURGICAL SITE INFECTIONS
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18.  Risk factors for nosocomial wound infection include:
 Advanced age,
 Obesity,
 Malnutrition,
 Diabetes,
 Infections at a remote site that spread through blood stream
 Time interval between pre-operative shaving of the site and
the surgery-if exceeds more than 12 hours.
SURGICAL SITE INFECTIONS
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19.  Nosocomial blood stream infections are the fourth common
cause of HAIs.
 Organisms: Coagulase negative staphylococci, S. aureus and
enterococci are increasingly reported recently followed by
gram- negative rods and Candida.
 Risk factors that predispose the patients to acquire a
nosocomial bloodstream infection include:
 Age ( <1 years and >60 years), and malnutrition
 Low immunity or severe underlying disease
 loss of skin integrity (burn or bed sore)
 Prolonged hospital stay, especially in ICUs
 Presence of intravascular catheters
BLOOD STREAM INFECTIONS
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20.  Standard (Routine) Precautions
 Standard precautions are a set of infection control practices
used to prevent transmission of diseases that can be acquired
by contact with blood, body fluids, non-intact skin (including
rashes), and mucous membranes. These measures should be
followed when providing care to:
 All individuals, whether or not they appear infectious/
symptomatic or not.
 All specimens (blood or body fluids) whether they appear
infectious or not.
 All needles and sharps whether they appear infectious or not.
PREVENTION OF HAIS
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21.  Components of standard precautions include:
 Hand hygiene:
 Wash hands promptly after contact with infective material
 Use no touch technique wherever possible
 Personal protective equipment's (PPEs):
 Wear gloves when expecting contact with blood, body fluids,
secretions, excretions, mucous membranes and contaminated
items and wash hands immediately after removing gloves.
 Sharp handling: AII sharps should be handled with extreme care
 Spillage cleaning: Clean up spills of infective material promptly
 Waste handling: Ensure appropriate biomedical waste
seggregation and disposal
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22.  Specific precautions
 Additional precautions are needed for preventing specific
modes of transmission.
 Airborne Precautions
 the following measures are required:
 Individual room should be provided with adequate ventilation
with negative pressure facility.
 Staff should wear high-efficiency masks in room
 Patient should be confined to the room.
PREVENTION OF HAIS
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23.  Droplet Precautions
 The following procedures are required:
 Individual room for the patient, if available
 Mask for healthcare workers
 Restricted movement of the patient; patient wears a surgical
mask while leaving the room.
PREVENTION OF HAIS
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24.  Contact Precautions
 These are required for patients with enteric infections and
diarrhea which cannot be controlled, or skin lesions which can
not be contained.
 Individual room for the patient if available; cohorting of patients
if possible
 Staff should wear gloves and gowns on entering the room.
 Hand washing should be done before and after contact with the
patient, and on leaving the room.
 Appropriate environmental and equipment cleaning,
disinfection, and sterilization to be followed.
PREVENTION OF HAIS
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25.  Precautions for Patients with MDROs
 The increased occurrence of multidrug resistant organisms
(MDROs) is a major medical concern. the spread of MDROs
such as multidrug resistant MRSA is usually by transient
carriage on the hands of healthcare workers.
 The following precautions are required for the prevention of
spread of epidemic of MRSA:
 Minimize ward transfers of staff and patients
 Ensure early detection of cases, especially if admitted from
another hospital; screening of high risk patients may be
considered
PREVENTION OF HAIS
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26.  Precautions for Patients with MDROs
 Isolate infected or colonized patients in a single room,
isolation unit or cohorting in a larger ward
 Reinforce hand washing by staff after contact with infected
or colonized patients
 Use gloves, gown or apron for handling MRSA contaminated
materials, or infected or colonized patients
 Consider treating nasal carriers with mupirocin
 Consider daily wash or bath by antiseptic detergents for
carriers or infected patients.
 Ensure careful handling and disposal of medical devices.,
linen, waste, etc.
 Develop guidelines specifying when isolation measures can
be discontinued.
PREVENTION OF HAIS
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