Antibiotic susceptibility of Neisseria meningitidis from healthy and diseased persons in Japan

Abstract

We examined the susceptibilities of 100 Neisseria meningitidis strains isolated between 1990 and 2004 to 12 antimicrobial agents, finding the MIC50 to be 0.031 microg/mL and that of MIC90 of benzylpenicillin (PCG), a type of penicillin, to be 0.063 microg/mL. Two strains showed intermediate resistance (MIC of 0.125-0.25 microg/mL). Two strains of the same origin also showed intermediate resistance (0.25-1 microg/mL) to ampicillin (ABPC). For cephems, MIC50 and MIC90 of cefotaxime (CTX) were both 0.004 microg/mL, while the MICs of ceftriaxone (CTRX) were all 0.004 microg/mL, showing the strongest antibacterial spectrum. The three carbapenems surveyed meropenem (MEPM), panipenem (PAPM), and imipenem (IPM) also had a strong antibacterial spectrum in ascending order, with the MIC50 and MIC90 of MEPM, which was lowest, being 0.008 microg/mL and 0.016 microg/mL. Some 97% of MICs for ciprofloxacin (CPFX) were 0.004 microg/mL but 3 strains showed resistance (0.125 microg/mL). No difference was seen between MICs of N. meningitidis strains originated from meningitis patients, patients other than meningitis, and healthy carriers. No difference was seen in MICs by serogroup (A, B, C, Y, W135 and NG).