Analysis of antimicrobial susceptibility of Neisseria gonorrhoeae epidemic strains to five antibiotics

Objective To investigate the antimicrobial susceptibility and the resistant trend of Neisseria gonorrhoeae strains isolated in Panyu in 2008 to penicillin,tetracycline,spectinomycin, ceftriaxone and ciprofloxacin.Methods The agar dilution method was used to determine the minimum inhibitory concentrations(MIC) to the above five antibiotics.The sensitivities of all strains to the five antibiotics were judged according to criteria used in the project of surveillance of gonococcal antibiotic susceptibility in the WHO Western Pacific Region.Penicillinase-producing Neisseria gonorrhoeae (PPNG) was detected by the paper acidometric method.Results In 107 isolates of Neisseria gonorrhoeae, 94 cases(94/107,87.9%) were penicillin-resistant bacteria,and 43 cases(43/107,40.2%) were PPNG ones.The resistance rate of Neisseria gonorrhoeae isolates was 88.8%to tetracycline;63 strains(58.9%) were plasmid-mediated high level tetracycline-resistant(TRNG);the ciprofloxacin resistance rate was 81.3%.Neither spectinomycin nor ceftriaxone-resistant strains were detected. MIC_(50) and MIC_(90) of penicillin,tetracycline and ciprofloxacin significantly exceeded the resistance standards,especially 1 and over 32 times higher for penicillin.Conclusion Neisseria gonorrhoeae is sensitive to spectinomycin and ceftriaxone,and the two antibiotics may be used as the first choice to treat Neisseria gonorrhoeae infection.The resistance rates of Neisseria gonorrhoeae to penicillin,tetracycline and ciprofloxacin are relatively high,indicating the three antibiotics are insensitive to gonorrhea.