关键词: 奈诺沙星, 金黄色葡萄球菌, 耐药, 突变位点

Abstract:

AIM: To determine the primary target of nemonoxacin and mutation position in S. aureus by genomic characterization of first and second step mutants. METHODS: Quinolone resistance-determining region(QRDR)mutations of gyrA, gyrB, and grlA of resistant mutants were identified by PCR amplification and gene sequencing. RESULTS: All the 4 first step mutants selected using nemonoxacin contained changes at codon 86, 439, and 440, but did not lead to amino acid substitution. For second-step mutants selected from first-step resistance strains, a novel second gyrA mutation (Ser-84→Leu) mutations was found. No mutations were found in grlA region of QRDR. CONCLUSION: DNA gyrase is the primary target of nemonoxacin in S. aureus. Mutation at position 84 may be the most important factor to influence the sensitivity of S. aureus.

Key words: nemonoxacin, staphlococcus aureus, drug resistance, mutation position