Antibiotics susceptibility and genetic characteristics analysis for quinolone resistant Campylobacter jejuni isolated from China / 中国人兽共患病学报

ABSTRACT

According to CLSI,agar dilution method was used to analyze the minimum inhibitory concentrations (MIC) of the nalidixic acid and ciprofloxacin for the isolates from different sources.Mutations in the quinolone resistant determining region (QRDR) of gyrA and gyrB were examined by DNA sequencing of 102 resistant C.jejuni isolates and 27 sensitive isolates.The results showed that 218 isolates(93.16％) were resistant to nalidixic acid among the entire tested 234 isolates.Among these,the resistant rates of the isolates from chicken feaces,duck feaces,human feaces,food animal and cow feaces were 100.00％,100.00％,97.96％,97.83％ and 77.97％,respectively.The 211 isolates(90.17％) were resistant to ciprofloxa-cin.Among these,the resistant rates of the isolates from chicken feaces,duck feaces,human feaces,food animal and cow feaces were 100.00％,100.00％,91.84％,95.65％ and 77.97％,respectively.The differences were both statistically significant.All of the resistant isolates on the QRDR of gyrA had Thr-86-Ile mutation.However,the point substitutions in gyrB gene were synonymous mutations.The results indicated that the C.jejuni isolates in this study showed highly resistant to nalidixic acid and ciprofloxacin.The Thr-86-Ile mutation on the QRDR of gyrA can cause highly resistant to quinolone and fluoroquinolone for C.jejuni.