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Activity of 18 antimicrobial agents against multi-resistant strains of Staphylococcus aureus isolated from intensive
Abstract:
During an outbreak of infections with multiple-resistant Staphylococcus aureus, 22 strains were isolated from 12 patients between November 1983 and March 1984 on two surgical intensive care units at Kiel University Hospital. Susceptibility of all strains was tested with the disc diffusion method and a microdilution test using different inocula of 10(2) and 10(5) cfu/ml. All strains were resistant to beta-lactam antibiotics, including thienamycin as well as to gentamicin, clindamycin, doxycycline, erythromycin and fosfomycin. Rifampicin was the most active substance in terms of w/v, followed by fusidic acid, ciprofloxacin, vancomycin, and trimethoprim/sulfamethoxazole. Netilmicin and chloramphenicol showed only moderate activity in relation to the antibiotic breakpoint, but were considered sensitive according to the disc diffusion test. Caution should be reserved for the use of imipenem against multiply-resistant staphylococci.
Insights
Multiple-resistant Staphylococcus aureus strains showed resistance to many antibiotics. Rifampicin and fusidic acid were most effective, while imipenem use requires caution.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- An outbreak of multiple-resistant Staphylococcus aureus occurred in surgical intensive care units.
- The study focused on strains isolated from patients between November 1983 and March 1984.
Purpose of the Study:
- To assess the antimicrobial susceptibility of isolated Staphylococcus aureus strains.
- To identify effective therapeutic agents against these resistant strains.
Main Methods:
- Antibiotic susceptibility testing using disc diffusion and microdilution methods.
- Inocula of 10(2) and 10(5) colony-forming units/ml were used for microdilution tests.
Main Results:
- All 22 strains were resistant to beta-lactam antibiotics, gentamicin, clindamycin, doxycycline, erythromycin, and fosfomycin.
- Rifampicin demonstrated the highest activity, followed by fusidic acid, ciprofloxacin, vancomycin, and trimethoprim/sulfamethoxazole.
- Netilmicin and chloramphenicol showed moderate activity, considered sensitive by disc diffusion.
Conclusions:
- Rifampicin and fusidic acid are potential treatment options for these resistant Staphylococcus aureus infections.
- Caution is advised when using imipenem against multiply-resistant staphylococci strains.