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Antimicrobial tolerance in group C and group G streptococci
The Journal of Antimicrobial Chemotherapy
|April 1, 1984
Summary
This study investigated antimicrobial activity against streptococci, finding penicillin, cephalothin, and vancomycin highly effective. Combinations proved bactericidal against tolerant strains, offering therapeutic options.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Group G and C streptococci are significant human pathogens.
- Understanding antimicrobial susceptibility is crucial for effective treatment.
- Tolerance to antibiotics can complicate therapeutic outcomes.
Purpose of the Study:
- To evaluate the in-vitro antimicrobial activity against clinical isolates of group G and C streptococci.
- To identify effective antimicrobial agents and combinations against these streptococci.
- To assess the prevalence and characteristics of antibiotic tolerance in these isolates.
Main Methods:
- In-vitro susceptibility testing of 61 clinical isolates (35 group G, 26 group C streptococci).
- Determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values.
- Evaluation of various antimicrobial agents and their combinations, including beta-lactams and vancomycin.
Main Results:
- Penicillin, cephalothin, and vancomycin exhibited potent activity (MIC90 values ≤ 0.12 mg/l).
- Antibiotic tolerance was observed in 9.8% of isolates, with specific agents implicated.
- Combinations of beta-lactams with gentamicin, or vancomycin with gentamicin/rifampicin, demonstrated bactericidal activity without antagonism.
Conclusions:
- Effective antimicrobial agents and bactericidal combinations are available for treating infections caused by group G and C streptococci.
- Therapeutic strategies should consider potential antibiotic tolerance in these organisms.
- Antimicrobial combinations offer viable options for achieving bactericidal activity against tolerant streptococcal strains.