EVALUATION OF THE STANDARDIZED DISK DIFFUSION AND AGAR DILUTION ANTIBIOTIC SUSCEPTIBILITY TEST METHODS BY USING STRAINS OF NEISSERIA-GONORRHOEAE FROM TUCUMAN, ARGENTINA

At present, most Neisseria gonorrhoeae testing is done with beta-lacta mase and agar dilution tests using common therapeutic agents. Generall y, in bacteriological diagnosis laboratories in Argentina, study of an tibiotic susceptibility of N. gonorrhoeae is based on beta-lactamase d etermination and agar dilution method using common therapeutic agents. The National Committee for Clinial Laboratory Standards (NCCLS) recen tly described a disk diffusion test that produces results similar to t he reference agar dilution method for antibiotic susceptibility of N. gonorrhoeae. We obtained 57 gonococcal isolates from patients attendin g a clinic for sexually transmitted diseases in Tocuman, Argentina. An tibiotic susceptibility tests using agar dilution and disk diffusion t echniques were compared. The established NCCLS interpretive criteria f or both susceptibility methods appeared to be applicable to domestic g onococcal strains. The correlation between the minimum inhibitory conc entration (MIC's) and the zones of inhibition was studied for penicill in, ampicillin, cefoxitin, spectinomycin, cefotaxime, cephaloridine, c ephalexin, tetracycline, norfloxacin and kanamycin. Dispersion diagram s showed a high correlation between both methods, with a sensitivity o f 89% and specificity of 91%.