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[Resistance to antibiotics of vibrio cholerae strains isolated in Angola]
E Ferreira1, M Costa, M V Vaz Pato
1Centro Nac. Invest. Cientifica, Luanda.
Abstract:
Among 87 strains of Vibrio choleare (78 Ogawa serotype and 9 Inaba serotype strains) isolated in Angola in 1987-1990, 86% exhibited multiple resistance to antimicrobials. Eighty-four to 86% of strains were resistant to ampicillin with beta-lactamase production (MIC greater than or equal to 512 mg/l), streptomycin (MIC greater than or equal to 64 mg/l), spectinomycin (MIC greater than or equal to 1,024 mg/l), and trimethoprime-sulfisoxazole (MIC greater than 1,024 mg/l). Seventy-four per cent of strains were resistant to kanamycin (MIC = 512 mg/l), 26% to chloramphenicol (MIC = 32 mg/l), 10% to tetracycline (MIC = 16 mg/l), and 10% to gentamycin (MIC greater than or equal to 32 mg/l). Transfer to E. coli K12 was associated with a substantial increase in expression of resistance to tetracycline and chloramphenicol (CAT type I), with MICs in the 128-512 mg/l range. Transfer rates to E. coli K12 of plasmids for the various resistance phenotypes were 10(-6)/10(-8). The size of the isolated plasmids was 100 Md in diameter and belonged to the incompatibility group inc 6-C.
Insights
Most Vibrio cholerae strains in Angola showed multiple antimicrobial resistance, particularly to ampicillin, streptomycin, and trimethoprim-sulfisoxazole. Resistance genes were transferable via plasmids, indicating a public health concern.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Vibrio cholerae is a significant cause of diarrheal disease worldwide.
- Antimicrobial resistance in V. cholerae poses a substantial threat to public health, complicating treatment and increasing morbidity and mortality.
- Understanding the patterns and mechanisms of antimicrobial resistance in V. cholerae is crucial for effective disease control.
Purpose of the Study:
- To investigate the antimicrobial resistance profiles of Vibrio cholerae strains isolated in Angola.
- To determine the prevalence of multiple drug resistance among these strains.
- To examine the transferability of resistance genes and identify associated plasmids.
Main Methods:
- Isolation and serotyping of Vibrio cholerae strains (Ogawa and Inaba).
- Antimicrobial susceptibility testing using minimum inhibitory concentration (MIC) determination.
- Plasmid isolation, characterization (size, incompatibility group), and transfer experiments to E. coli K12.
Main Results:
- 86% of 87 V. cholerae strains exhibited multidrug resistance.
- High resistance rates were observed for ampicillin (86%), streptomycin (84%), spectinomycin (86%), and trimethoprim-sulfisoxazole (84%).
- Resistance to tetracycline and chloramphenicol was transferable via 100-Md plasmids belonging to incompatibility group Inc 6-C, with increased expression in E. coli K12.
Conclusions:
- Vibrio cholerae strains circulating in Angola during 1987-1990 displayed extensive multidrug resistance.
- The presence of transferable plasmids carrying resistance genes, particularly for tetracycline and chloramphenicol, is a significant concern.
- These findings highlight the need for ongoing surveillance and antimicrobial stewardship to combat cholera outbreaks.