03 Infection control in hospital settings. Multiresistant pathogens

unideb 2025

What is infection control in general?

population/community level data collection and intervention in relation to infectious diseases

What is infection control in a hospital setting?

hospital hygiene

primary target population in a hospital setting

1. patients

2. health care staff

secondary target population in a hospital setting

1. visitors

2. non-health care staff (administrative, janitorial, etc.)

Classic approaches to infection control?

1. Isolation of infectious patient

2. Isolation of susceptible patient (protective or reverse isolation)

3. Disinfection (germ reduction)

4. Sterilization (germ elimination)

5. Hazardous waste management

6. Disinfective cleaning

7. Hygiene in food service/catering

8. Hygiene in laundering

9. Pest control (insects, rodents)

Advanced approaches to infection control? (aka surveillance)

1. Data collection to identify hospital infections (aka. nosocomial infections)

2. Built on evidence-based definitions

3. Field work carried out by infection control nurses

4. Managed by hospital epidemiology/preventive medicine/public health specialist physicians

5. Computer analysis of data

6. Action response planning and implementation

What is an example of surveillance?

general microbiological monitoring

What is general microbiological monitoring?

1. Daily evaluation of microbiological findings

2. Identification of positive blood cultures and multiresistant pathogens

3. Microbiological analysis of the most commonly found pathogens

4. Antibiotic resistance monitoring

Most common types in ICU patients

respiratory tract and bloodstream infections

Why is ICUs a hotbed of nosocomial infections?

Invasive interventions are a key causal factor

Colonization

microorganism permanently lives and multiplies on body surface without causing disease

Infection

when there are risk factors, infectious disease can develop from colonization

Normal flora versus Nosocomial flora

more Gram negatives, more resistant bacteria in latter

Nosocomial infection

infection acquired in a health care setting

Standard isolation

designated room and equipment; involvement and impact on staff, patient, and visitors/relatives

Contact isolation

staff must wear protective equipment

patient zone

1. assumed to be rapidly contaminated by patient’s flora

2. must be cleaned between patients

3. two critical sites: clean site & body fluid site

Healthcare zone

assumed to contain hospital germ strains source of exogenous infection

5 moments for hand hygiene by WHO

1. before touching a patient

2. before a procedure

3. after a procedure or body fluid exposure risk

4. after touching a patient

5. after touching a patient’s surroundings

Polyresistance (PDR)

resistance to at least 2 antibiotic groups effective against the wild type

Multiresistance (MDR)

resistance to at least 3 antibiotic groups effective against the wild type

Panresistance (extended drug resistance, XDR)

resistance to all (or all but one) known antibiotics

What is the cause of emerging multiresistance?

• antibiotic (ab) misuse

1. low adherence to institutional ab policy

2. ab without prescription

3. ab in viral infection

4. poor compliance by patients

• ab overuse in animal farming

1. exceeds human medical use

2. preventive use against infections

3. greater weight yield

• poor infection control

What can we do against the increasing tendency of nosocomial infection?

1. screening

2. risk group awareness: e.g. medical devices inserted for a long time

3. proper infection control practice

4. appropriate, rational antibiotic policy

MRSA types

1. CA-MRSA (community-acquired/associated)

2. HA-MRSA (hospital-acquired)

3. LA-MRSA (livestock-acquired)

CA-MRSA (community-acquired/associated)

1. lower levels of antibiotic resistance

2. highly pathogenic (may even cause serious infections in healthy young persons)

3. severe tissue damage (Panton-Valentine leukocidin)

HA-MRSA (hospital-acquired)

1. higher levels of resistance

2. relatively less pathogenic