Nosocomial infections, also known as hospital-acquired infections, develop in patients after admission to the hospital for treatment of other illnesses. Sources can be exogenous from other patients, staff, or contaminated equipment, or endogenous from the patient's own microflora. Factors that increase risk include older or younger age, underlying illnesses, prior infections, and invasive medical procedures. Common types of nosocomial infections include urinary tract, respiratory, surgical site, bloodstream, and gastrointestinal infections. Prevention strategies involve proper sterilization, cleaning, hand hygiene, aseptic techniques, protective clothing, equipment disinfection, hospital design, and surveillance.

1. Bsc Nursing
Microbiology
Unit – 3 (nosocomial
infection )
BY :- PRAGYA TIWARI

2. Nosocomial Infection
 Hospital acquired infection Are those which are developed in a patient after
admission to the hospital due to some other illness.
 Hospital have generally served as a source of infection to patient after intering
into hospital specially after admission. This is known as nosocomial infection
(nosocomion mean “Hospital”).
 These are defined as infection developing patient after admission to the hospital,
which were neither present, nor in incubation at the time of hospitalisation.
 These infection may manifest during their stay in hospital or sometimes after the
patient discharge.

3. Source
 EXAGENOUS: It source may be another person in the hospital (cross
infection) or a contaminated item or equipment of building service
(inuironment infection)
Eg : Contact with Other patients & stuff
Environmental source
Inanimate objects
 ENDOGENOUS: The infecting organisms are drived from the patient own
skin, GI or upper respiratory system.

4. Factors inducing hospital infections are
1. AGE: Neonate and elderly age people are more susceptible for hospital acquired infection
becouse of there longer stay &with inefficient immunity.
2. SUSCEPTIBILITY: Hospitalised patient with pre-existing disease. Like – diabetes etc are high risk
group & more susceptible to infection.
3. INFECTED PATIENT: Community acquired or non – hospital infection. The patient inters the
hospital due to pathogenic micro-organism.
4. HOSPITAL ENVIRONMENT: Where if not clean transmit disease easily.
5. SURGICAL & DIAGNOSTIC PROCESS: The natural difence mechanism of body surface may be
by pass by the injury or by a diagnostic or therapeutic interventions like : catheter.
6. BLOOD TRANSFUSION:-
MODE OF TRANSMISSION
 CONTACT: Most common route of transmission for hospital infection are:-
• Direct contact: spread from person to person.

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•Indirect contact: Spread via contaminated hands & equipment.
 AIR BORN SPREAD: Infections may be spread by air
•Dropletes: Respiratory disease transmitted by inhalation
•Dust: From beding, floor, a wound during dressing & from the skin etc.
 ORAL ROUTE: Hospital food cantain gram –ve bacilli which are most aften antibiotics resistance,
which may calanies the gut and later cause infection in susptible host.
 PARENTERAL ROUTE : (Insulation) with the use of disposable, needles, syrings & other device
& transmission of infection by parentral route in frequent. However certain infection may be
transmitted by blood transfusion & tissue donation & contaminated infusion fluid & from
accidental injury with contaminated sharp with HIV.
 CROSS INFECTION & SELF INFECTION: Self infection may cause due to transfer into the
wound of the staphalocucci.
Cross infection may result from staphalocucci derived from other patient or healthy stuff.
 ANIMAL : Zoonatic infection are transmitted through animal.
 INSECTS: Acts as actors in transmission on of several disease.

6. Common hospital acquired infection
 Urinary tract infection: Most hospital acquired infection urinary tract are
associated with. Urethral catheterization.infection can be prevented by strict
asepsis during catheterization.
 Respiratary infection: Aspirations in uncanrious patient and pulmonary
ventilation or instrumentation to deal to nosocomial pneumonia.
 Wound & skin sepsis :The encidence of post operatic infection is higher in
elderly patients most wauna infection manifest with in a weeK of surgery.
 Septesemia and bacterimia: These may be consequences of infection at any site
but are commonly caused by infected intervenus cannula intravenus be
rehydration in diarrhoea should be restricted to emergencies & should be
replaced by oral fluids as earliest possible.

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 GI tract infection: Food paisoning & neanatal septicemia in hospital have been
reported.
 Burn: It is a primary suspect ( pseudo manas) in burn infection.

8. Prevention and Control
The hospital acquired infection can be prevented by following means.
 Sterilization: The pravision of sterile instruments dressing, surgical gloves, face
mask, clothing is very important in hospital practise.
 Cleaning & Disinfection: The general hospital inuironment can be kept in good
order by altention of basic cleaning ,waste disposal and laundry.
 Skin disinfection and antiseptic:-
•Hand washing :Through hand washing after any procedure, involving
nursing care or close cantact with the patient is essential.
•Asepsis: The asepsis is divided into 2 categories
1. Medical 2. Surgical

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 Protective clothing: Defferent activities within the hospital require defferent Dgree of
protection to staff and patients.
 Equipment: It should be assist to determine the appropriate method frequency &site of
diontamination
 Haspital building & design: The rautun maintance of the hospital building to insure that
surface whenever possible are smooth and easy to clean.
1. Monitoring : Monitoring of the physical performance of air canditaninh plants and
machanry used disinfection and sterilization is essential.
2. Surveillance and ales laboratories: Detection and cathetirization of hospital infection
incident of etc