2. DEFINTION
Hospital-acquired infections or Nosocomial infections or
Healthcare-associated infections 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 at the time of admission
• Symptoms should appear at least after 48 hours after
admission
• This include infections acquired in the hospital with appearing
after discharge, and also occupational infections among staff
of the hospital care facility.
3. FACTORS AFFECTING HAIs
• Immune status: Most admitted patients have impaired
immunity either as a part of their pre-existing disease.
• Hospital environment: The hospital environment harbors a
greater magnitude of microorganisms than that of community.
• Hospital organisms: Most of the organisms present in the
hospital environment are multidrug resistant.
• Diagnostic or therapeutic interventions such as insertion of
IV needle or urinary catheters, or ET tube, may introduce
infection in susceptible patients.
4. SOURCES OF INFECTION
Endogenous Source
Involve patient's own microbial flora which may invade
the patient's body during some surgical or instrumental procedurs.
Exogenous Source
Exogenous sources are from hospital environment, staff
or patients.
• Environmental: Inanimate objects, air, water and food in the
hospital.
• Healthcare workers may be potential carriers, harbouring
many organisms; which may be multidrug resistant.
• Other patients of the hospital may also be the source of
infection.
5. MICROORGANISMS IMPLICATED IN
HAIs
HAI 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.
ESKAPE pathogens:
• Enterococus faecium
• Staphylococcus aureus
• Klebsiella pneumoniae
• Acinetobacter baumannii
• Pseudomonas aeruginosa
• Enterobacter species.
6. MODE OF TRANSMISSION
Contact Transmission
Direct contact (Most important & frequent mode)
Indirect contact (Dress, Gloves, Instrument, Parenteral rout)
9. TYPE
Though several types of HAIs exist, there are four most
common types
1. Catheter-associated urinary tract infection (CAUTI, 33%)
2. Central line-associated blood stream infection (CLABSI, 13%)
3. Ventilator-associated pneumonia (VAP, 15%)
4. Surgical site infection (SSI, 31%).
10. Catheter-associated Urinary Tract Infection
• UTI accounts for the majority of HAIs.
• It can be
Catheter associated (CAUTI)
Non-catheter associated
Risk factors
i) Advanced age,
ii) Female gender,
iii) Placement of a urinary catheter for >2 days
Organisms:
I. Gram-negative (most common E. coli).
II. Gram-positive (occasionally cause CAUTI)
11. Central Line Associated Blood Stream Infection
Risk factors
Patient related: Age (<l year and >60 years)
Malnutrition
Low immunity
Loss of skin integrity (burn or bed sore)
Prolonged stay in ICUs.
Device related: Presence of central line
HCW related: Poor infection control practices such as hand hygiene
Organisms:
• Coagulase negative staphylococci and S. aureus
• Gram-negative rods
• Candida
12. Ventilator-associated Pneumonia
Ventilator-associated pneumonia (VAP) are the second common
cause of HAIs next to UTI.
Risk factors
Device related: Endotracheal intubation
Patient related: Prolonged ICU
Aspiration of oropharyngeal flora
HCW related: Poor infection control practices
Organisms: Acinetobacter species
Pseudomonas species
13. Surgical site infection
SSI is defined as infection that develops at the surgical site within 30 days
of surgery (within 90 days for breast, cardiac and joint surgeries).
Risk factors
Advanced age, Obesity, Malnutrition
Diabetes
Preoperative shaving of the site
Inappropriate timing of prophylactic antimicrobial agent
Organisms:
S aureus
Anaerobic Bacteria
Gram-negative rods
16. Transmission-based precautions
These are the additional precautions taken over with above the standard
precautions when a disease of a specific transmission is suspected and
where standard precautions may not be sufficient enough to prevent the
transmission of infection.
• Isolation
• Patient movement
• Role of HCW
