Related Experiment Videos
Methicillin-resistant Staphylococcus aureus in nosocomial infections in the surgical ward and operating room
Abstract:
In this study 214 strains of Staphylococcus aureus were isolated from clinical specimens on the surgical ward from 1983 to 1988 and in addition, 62 airborne strains were collected in the operating room. Highly methicillin-resistant strains of S.aureus (H-MRSA, MIC greater than 100 micrograms/ml) not detected in 1983 showed a significant increase in frequency by 1987 accounting for about 60% of MRSA (MIC greater than or equal to 12.5 micrograms/ml). Countermeasures instituted in 1987 such as the use of disinfectant chlorhexidine alcohol significantly decreased the frequency of MRSA and H-MRSA isolates in 1988. In our study of coagulase type, MRSA type IV strains were predominant until 1984, whereas after 1986 type II was prevalent. All airborne strains collected in the operating room were methicillin-sensitive S.aureus, with type VII currently epidemic. We therefore concluded that cross infection with MRSA took place on the surgical ward rather than in the operating room.
Insights
Highly methicillin-resistant Staphylococcus aureus (H-MRSA) increased significantly on surgical wards until 1987. Interventions reduced H-MRSA, indicating surgical ward cross-infection, not operating room contamination.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Hospital Epidemiology
Background:
- Staphylococcus aureus is a common cause of hospital-acquired infections.
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant clinical challenge.
- Understanding the sources and transmission of MRSA is crucial for infection control.
Purpose of the Study:
- To investigate the prevalence and trends of MRSA and H-MRSA in clinical and airborne samples.
- To identify the primary site of MRSA cross-infection within a hospital setting.
- To evaluate the impact of infection control interventions on MRSA frequency.
Main Methods:
- Isolation and characterization of 214 clinical S. aureus strains from surgical wards (1983-1988).
- Collection and analysis of 62 airborne S. aureus strains from operating rooms.
- Monitoring of MRSA and H-MRSA (MIC ≥ 12.5 and >100 µg/ml, respectively) frequency over time.
- Coagulase typing of MRSA strains.
- Assessment of infection control measures, including chlorhexidine alcohol disinfectant.
Main Results:
- Highly methicillin-resistant S. aureus (H-MRSA) increased from undetectable levels in 1983 to 60% of MRSA by 1987.
- Implementation of chlorhexidine alcohol in 1987 led to a significant decrease in MRSA and H-MRSA in 1988.
- MRSA coagulase types shifted from predominant type IV (until 1984) to type II (after 1986).
- All airborne operating room strains were methicillin-sensitive S. aureus, with type VII epidemic.
Conclusions:
- Cross-infection with MRSA primarily occurred on the surgical ward, not within the operating room.
- Effective infection control measures can significantly reduce the incidence of MRSA and H-MRSA.
- Surveillance of MRSA strains and their sources is essential for targeted interventions.