Antibiotic usage and methicillin-resistant Staphylococcus aureus: an analysis of causality

breakpoints recommended by the National Committee for Clinical Laboratory Standards. The MIC50s and MIC90s of the various antibiotics tested for the 11 ciprofloxacinresistant strains were as follows: penicillin, 2 mg/L and 2 mg/L, respectively; tetracycline, 2 mg/L and 2 mg/L, respectively; ciprofloxacin, 2 mg/L and 2 mg/L, respectively; cefuroxime, 0.5 mg/L and 1 mg/L, respectively; ceftriaxone, 0.03 mg/L and 0.03 mg/L, respectively; and spectinomycin, 8 mg/L and 16 mg/L, respectively. The distributions of PPNG, TRNG, CMRNG , CMRNG P and CMRNG T among the 94 isolates are shown in the Table; all but 11 (11.7% ) were resistant to penicillin, tetracycline or both. To the best of our knowledge, this is the first survey of antimicrobial susceptibility among N. gonorrhoeae strains isolated from commercial sex workers in Bangladesh. The high prevalence of resistance or reduced susceptibility to ciprofloxacin demonstrated in this study undermines confidence in the antibiotics currently regarded as primary therapy of patients with gonorrhoea in Bangladesh. Never the less, the results of this investigation emphasize the need to monitor periodically the antimicrobial susceptibility patterns of gonococcal isolates. Such surveys can provide important information concerning trends in resistance to relevant antibiotics and can thereby facilitate the administration of optimal therapy.