Related Experiment Videos
Effect of delayed infection control measures on a hospital outbreak of methicillin-resistant Staphylococcus aureus
S Harbarth1, Y Martin, P Rohner
1Infection Control Programme, Department of Internal Medicine, University of Geneva Hospitals, Geneva, Switzerland.
Abstract:
All patients positive for methicillin-resistant Staphylococcus aureus (MRSA) at the University Hospitals of Geneva, Switzerland, between 1989 and 1997 (N = 1771) were included in a cohort study to evaluate the consequences of delayed containment of a hospital-wide outbreak occurring during a 4-year absence of MRSA control measures. The effects of efforts to control both the MRSA reservoir and the number of bacteraemic patients were assessed. Intensive infection control measures were initiated in 1993 and included patient screening, on-site surveillance, contact isolation, a computerized alert system, and hospital-wide promotion of hand hygiene. An increase in the rate of new MRSA-infected or -colonized patients was observed between 1989 and 1994 (from 0.05 to 0.60 cases per 100 admissions), which subsequently decreased to 0.24 cases in 1997 (P<0.001). However, the proportion of laboratory-documented methicillin-resistant isolates among all S. aureus showed little variation in the years from 1993 onwards (range, 19-24%), reflecting the result of an increase in the number of screening cultures. The annual number of patients with MRSA bacteraemia strongly correlated with the hospital-wide prevalence of MRSA patients (R(2)= 0.60; P = 0.01) and the rate of new MRSA patients (R(2)= 0.97; P<0.001). Consequently, the attack rate of nosocomial MRSA bacteraemia served as an excellent marker for the MRSA patient reservoir. In conclusion, despite delayed implementation, infection control measures had a substantial impact on both the reservoir of MRSA patients and the attack rate of MRSA bacteraemia.
Insights
Implementing infection control measures significantly reduced methicillin-resistant Staphylococcus aureus (MRSA) spread and bloodstream infections in a hospital setting. These interventions effectively controlled the MRSA patient reservoir and lowered nosocomial bacteraemia rates.
Area of Science:
- Infectious Diseases
- Hospital Epidemiology
- Public Health
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat in healthcare settings.
- A 4-year absence of control measures at University Hospitals of Geneva led to a widespread MRSA outbreak.
- Understanding the impact of delayed containment and subsequent control efforts is crucial for infection prevention.
Purpose of the Study:
- To evaluate the consequences of delayed containment of a hospital-wide MRSA outbreak.
- To assess the effectiveness of infection control measures on the MRSA reservoir and bacteraemia rates.
- To determine the relationship between MRSA patient prevalence and nosocomial MRSA bacteraemia.
Main Methods:
- A cohort study including 1771 MRSA-positive patients from 1989 to 1997.
- Implementation of intensive infection control measures in 1993: patient screening, surveillance, isolation, alert system, and hand hygiene promotion.
- Statistical analysis to correlate MRSA prevalence, new case rates, and bacteraemia incidence.
Main Results:
- The rate of new MRSA cases increased from 1989 to 1994 (0.05 to 0.60 per 100 admissions) but decreased to 0.24 by 1997 (P<0.001).
- The proportion of MRSA among all S. aureus isolates remained stable (19-24%) from 1993 onwards due to increased screening.
- Annual MRSA bacteraemia cases strongly correlated with MRSA patient prevalence (R(2)=0.60, P=0.01) and new case rates (R(2)=0.97, P<0.001).
Conclusions:
- Delayed implementation of infection control measures had substantial negative consequences.
- Intensive infection control measures initiated in 1993 significantly reduced MRSA patient reservoir and bacteraemia attack rates.
- The attack rate of nosocomial MRSA bacteraemia is a reliable marker for the MRSA patient reservoir.