Antimicrobial resistance of clinical and environmental strains of Vibrio cholerae isolated in Lima-Peru during epidemics of 1991 and 1998

ABSTRACT

The susceptibility in vitro of 71 isolations of V. cholerae was evaluated: 24 of clinical origin and 47 strains of clinical and environmental origin collected in the epidemic of 1991 and during the outbreak epidemic of 1998 in Lima-Peru respectively. The biochemical and serological tests carried out established that 43 (60,6 percent) corresponded to the serogroup O1 Ogawa of the 1998 epidemic; 26 (36.6 percent) were of the serotype Inaba, being 24 of them isolated in 1991. Two strains did not belong to the serogroup O1. By means of disk diffusion method and Minimal Inhibitory Concentration (MIC), 15 strains with multi-resistance to antibiotics were determined, 10 of which were of clinical origin and 5 of natural origin, showing 9 antibiotypes with different resistance pattern. The evaluation of susceptibility in front of the vibriostatic agent O/129, demonstrated that 11.4 percent of the strains, collected in 1998, presented resistance to a concentration of 150 æg. A direct relationship among the resistance that presented the strains of clinical and environmental origin isolated in 1991 and 1998 was established as much for tetracycline, sulfa/trimethoprim and 0/129; 88.6 percent of the clinical strains of the year 1998 presented resistance to these three drugs, while 100 percent of clinical strains isolated in 1991 were sensitive to O/129 (150 µg), sulfa/trimethoprim and tetracycline. We conclude that V. cholerae O1 has increased its resistance to antimicrobial drugs of clinical use in the same way it is also losing susceptibility to the vibriostatic compound O/129 for what their use is not recommended for taxonomic purposes.