Drug susceptibility testing in vitro of 49 strains of Neisseria meningitides

Objective The study was conducted to evaluate the altering patterns of antibacterial drug sensitivity of isolates of Neisseria meningitidis (Nm) in China from 2005 to 2006 for the selection of antibacterial drugs on patients with epidemic meningitis. Methods The broth dilution minimum inhibitory concentrations (MICs), Kirby-Bauer susceptibility test (K-B) and E-test were employed to determine the in vitro antibacterial drug susceptibility of 49 strains (16 strains of Group A and 33 of Group C) of Nm isolated from patients from 2005 to 2006. Results A total of 16 strains of Group A Nm showed resistance to co-trimoxazole, tetracycline, levofloxacin and nalidixic acid, and resistance or moderate sensitivity to ciprofloxacin. 33 strains of Group C Nm were resistant to cotrimoxazole; 31 (93.9%) of Group C strains were resistant to nalidixic acid; 20(60.6%) of Group C strains were resistant to levofloxacin; 17(51.5%) Group C strains were resistant to ciprofloxacin. Four strains of Group A and one strain of Group C Nm were found not sensitive to penicillin. Conclusion General sulfa drugs and quinolone resistance was found in Group A and C Nm strains in China from 2005 to 2006. As a result, these drugs are not applicable for the clinical management or preventative administration of epidemic meningitis in China. Results from the KB test, broth dilution MICs and E-test have a high consistency in the study.