1. Hospital Acquired (Nosocomial) Infections
III MBBS
Dr Ekta, Microbiology

2. Objectives Definition of Nosocomial infection
Sites of Nosocomial infection
Modes of transmission
Infection control program
Prevention of Nosocomial infection
Preventing infections of staff.
Dr Ekta, Microbiology

3. Definition
A nosocomial infection — also called “hospital acquired infection (HAI)” can be defined as:
An infection acquired by a patient during hospital care which was not present or incubating at the time of admission. This includes infections acquired in the hospital but appearing after discharge (after 48 hrs of discharge)
An infection acquired in hospital by a patient who was admitted for a reason other than that infection.
Dr Ekta, Microbiology

4. Types of Nosocomial Infections
Urinary tract infections (UTI)
Surgical site infections (SSI) major types
Pneumonia
Blood stream infections
catheter associated
Septicemia
Others
Skin & soft tissue infections e.g. bed sores
Gastroenteritis
Dr Ekta, Microbiology

5. Factors influencing the development of HAI
The microbial agent
Patient susceptibility
Environmental factors
Bacterial resistance
Dr Ekta, Microbiology

6. Microbial agent Characteristics of micro-organisms
Resistance to antimicrobial agents,
Intrinsic virulence, and
Amount (inoculum) of infective material.
Source of micro-organism: from
another infected person in the hospital
Patient’s own flora
an inanimate object or substances recently contaminated from another human source
Most infections acquired in hospital today are caused by microorganisms which are common in the general population, in whom they cause no or milder disease than among hospital patients (S. aureus, CONS, Enterococci, Enterobacteriaceae).
Dr Ekta, Microbiology

7. 2. Patient susceptibility
Important patient factors influencing acquisition of infection include
Age – infancy & old age
Immune status - AIDS
Underlying disease - malignancies, leukaemia, diabetes mellitus, renal failure
Diagnostic and therapeutic interventions
biopsies, endoscopic examinations
catheterization, intubation/ventilation & suction and
surgical procedures
Immunosuppressive drugs or Irradiation
Malnutrition
Dr Ekta, Microbiology

8. 3. Environmental factors
Crowded conditions within the hospital
Frequent transfers of patients from one unit to another, and
Concentration of patients highly susceptible to infection in one area (e.g. newborn infants, burn patients, intensive care )
Dr Ekta, Microbiology

9. 4. Bacterial Resistance
Widespread use of antimicrobials for therapy or prophylaxis (including topical)
Emergence of new resistant strains
Increased prevalence of multidrug resistant organisms like Klebsiella, Pseudomonas aeruginosa and Acinetobacter
Dr Ekta, Microbiology

10. Micro-organisms associated with HAI
Bacteria – most common nosocomial pathogen
Commensal bacteria – CONS, E.coli
Pathogenic bacteria – S.aureus, beta hemolytic streptococci, E.coli, Klebsiella, Proteus, Pseudomonas
Viruses –
hepatitis B and C viruses (transfusions, dialysis, injections, endoscopy),
respiratory syncytial virus,
rotavirus and enteroviruses (transmitted by hand-to-mouth contact and via the faecal-oral route)
Dr Ekta, Microbiology

11. Micro-organisms associated with HAI
Parasites –
Giardia lamblia
Cryptosporidium
Fungi
Candida albicans,
Aspergillus spp.,
Cryptococcus neoformans
Dr Ekta, Microbiology

12. Reservoirs & transmission
Micro-organisms can be acquired in several ways:
Endogenous infection (permanent or transient flora of the patient) e.g. Gram-negative bacteria in the digestive tract frequently cause surgical site infections after abdominal surgery or urinary tract infection in catheterized patients.
Exogenous cross infection (Flora from another patient or member of staff) through
direct contact
airborne droplets
via staff contaminated through patient care (hands, clothes,nose and throat) who become transient or permanent carriers
objects contaminated by the patient (including equipment), the staff’s hands, visitors or other environmental sources
Dr Ekta, Microbiology

13. Prevention of HAI Reducing person-to-person transmission
Hand decontamination and appropriate aseptic practice
Personal hygiene
Clothing, Masks & Gloves
Safe injection practices
Isolation strategies
Dr Ekta, Microbiology

14. Prevention of HAI Preventing transmission from the environment
Cleaning of the hospital environment
Disinfection of patient equipment
Sterilization of medical devices, linens
Dr Ekta, Microbiology

15. Prevention of HAI
Protecting patients with appropriate use of prophylactic antimicrobials, nutrition, and vaccinations
Limiting the risk of endogenous infections by minimizing invasive procedures , and promoting optimal antimicrobial use
Surveillance of infections, identifying and controlling outbreaks
Prevention of infection in staff members
Enhancing staff patient care practices, and continuing staff education.
Dr Ekta, Microbiology

16. Measures for Prevention of common nosocomial infections
UTI
Limit duration of catheter
Aseptic technique at insertion
Maintain closed drainage
Dr Ekta, Microbiology

17. Measures for Prevention of common nosocomial infections
SSI
Surgical technique
Clean operating environment
Staff attire
Limiting preoperative hospital stay
Preoperative shower and local skin preparation of patient
Optimal antibiotic prophylaxis
Aseptic practice in operating room
Surgical wound surveillance
Dr Ekta, Microbiology

18. Measures for Prevention of common nosocomial infections
Pneumonia
Ventilator-associated (VAP)
Aseptic intubation and suctioning
Limit duration
Non-invasive ventilation
Others
Influenza vaccination for staff
Isolation policy
Sterile water for oxygen and aerosol therapy
Prevention of Legionella and Aspergillus during renovations
Dr Ekta, Microbiology

19. Measures for Prevention of common nosocomial infections
Vascular device infections
All catheters
Closed system
Limit duration
Local skin preparation
Aseptic technique at insertion
Removal if infection suspected
Central lines
Surgical asepsis for insertion
Limitation of frequency of dressing change
Antibiotic-coated catheter for short term
Dr Ekta, Microbiology

20. Control of endemic antibiotic resistance
Ensure appropriate use of antibiotics (optimal choice, dosage and duration of antimicrobial therapy and chemoprophylaxis based on defined hospital antibiotic policy, monitoring and antibiotic resistance, and up-to-date antimicrobial guidelines).
Institute protocol (guidelines) for intensive infection control procedures and provide adequate facilities and resources, especially for handwashing, barrier precautions (isolation), and environmental control measures.
Improve antimicrobial prescribing practices through educational and administrative methods
Limit use of topical antibiotics.
Dr Ekta, Microbiology

21. Preventing infections of staff
Health care workers (HCW)
are at risk of acquiring infection through occupational exposure
can also transmit infections to patients and other employees
HCW’s health should be reviewed at recruitment
Immunizations recommended for staff include: hepatitis A and B, yearly influenza, measles, mumps, rubella, tetanus, diphtheria
Specific postexposure policies must be developed, and compliance ensured for: HIV, HAV, HBV, HCV, N. meningitidis, M. tuberculosis, VZV, HEV, C. diphtheriae, B.pertussis, and rabies
Dr Ekta, Microbiology

22. Infection Control Team
Investigating & controlling out breaks
Formulating appropriate admissions guidelines
Nursing & treatment of infectious patients
Sterilization & disinfection practices Surveillance
Determining antibiotic policy & immunization schedules
Educating patients & hospital personnel's on infection control
Soap water & common sense – Sir William Osler
Dr Ekta, Microbiology

23. Simplified criteria for surveillance of Nosocomial Infections
Type of
Nosocomial
infection
Simplified criteria
UTI
Positive urine culture (1 or 2 species) with at least 105
bacteria/ml, with or without clinical symptoms
SSI
Any purulent discharge, abscess, or spreading cellulitis
at the surgical site during the month after the operation
Respiratory infection
Respiratory symptoms with at least two of the following
signs appearing during hospitalization:
— cough
— purulent sputum
— new infiltrate on chest radiograph consistent with Infection
Dr Ekta, Microbiology

24. Simplified criteria for surveillance of Nosocomial Infections
Type of Nosocomial
infection
Simplified criteria
Vascular catheter infection
Inflammation, lymphangitis or purulent discharge
at the insertion site of the catheter
Septicaemia
Fever or rigours and at least one positive blood
culture
Dr Ekta, Microbiology

25. Impacts Increased morbidity & mortality Increased costs –
increased use of drugs,
the need for isolation, and
the use of additional laboratory and other diagnostic studies.
Longer duration of stay in hospital
Dr Ekta, Microbiology