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[Staphylococcus aureus nosocomial infections in an intensive care milieu (1985-1989) in Tunis]
A Ben Hassen1, T Ben Abdallah, A Kamoun
1Laboratoire de Microbiologie, Hôpital Charles-Nicolle, Tunis.
Abstract:
221 strains of Staphylococcus aureus oxacillin resistant (MetiR) caused nosocomial infections were isolated from 1985 to 1989 in a medical intensive care unit. The survey of susceptibility to antibiotics was established according to the computerized data of disk susceptibility test. The resistance phenotypes to beta-lactams, aminoglycosides and macrolides were established for epidemiological study. S. aureus infections were mainly bacteraemia (31%) and peritonitis (12%). These isolates were resistant to oxacillin with a high level (mean MIC 386 micrograms/ml). Their resistance phenotypes were MLSBc (constitutive resistance to macrolides, lincosamine and streptogramines B) in 53% and S + KGT (resistance to streptomycin, kanamycin, gentamicin and tobramycin) in 61%. All the isolates were susceptible to pristinamycin and vancomycin (MIC 0.1 and 2 micrograms/ml). These phenotypes related to the spread of multiply drug resistant strains were responsible of nosocomial outbreaks. Strains with the same pattern of resistance were isolated among the medical staff and in the environment. Infection control measures allowed to stop these outbreaks.
Insights
Methicillin-resistant Staphylococcus aureus (MetiR) caused significant nosocomial infections. Effective infection control measures successfully halted outbreaks of these multidrug-resistant strains.
Area of Science:
- Microbiology
- Infectious Diseases
- Epidemiology
Context:
- Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MetiR) were prevalent in a medical intensive care unit between 1985 and 1989.
- A total of 221 MetiR strains were isolated, primarily causing bacteremia (31%) and peritonitis (12%).
Purpose:
- To conduct an epidemiological study of antibiotic susceptibility and resistance phenotypes in MetiR strains.
- To investigate the spread of multidrug-resistant strains and identify effective control measures.
Summary:
- Antibiotic susceptibility testing revealed high-level oxacillin resistance (mean MIC 386 µg/ml) in all isolates.
- Prevalent resistance phenotypes included MLSBc (53%) and S + KGT (61%). All strains remained susceptible to pristinamycin and vancomycin.
- Identical resistance patterns were observed in strains from medical staff and the environment, indicating potential transmission routes.
Impact:
- The findings highlight the emergence and spread of multidrug-resistant S. aureus strains during nosocomial outbreaks.
- Implementation of infection control measures was crucial in successfully containing and stopping these outbreaks.