ABSTRACT
<p><b>OBJECTIVE</b>To investigate genetic and antibiotic resistance characteristics of Campylobacter jejuni (C. jejuni) isolated from Shenzhen.</p><p><b>METHODS</b>Multilocs sequence typing and agar dilution methods were used to define the genotype and antibiotic resistance of C. jejuni, respectively.</p><p><b>RESULTS</b>In total, 126 C. jejuni strains were isolated. The prevalence of C. jejuni was 5.3% in diarrheal patients. The prevalence in poultry meat (36.5%) was higher than that in cattle meat (1.1%). However, the prevalence in poultry cloacal swabs (27.0%) was lower than that in cattle stool (57.3%). Sixty-two sequence types were obtained, among which 27 of the STs and 10 alleles were previously unreported. The most frequently observed clonal complexes were ST 21 (11.9%), ST-22 (10.3%), and ST-403 (7.1%). ST-21, ST-45, ST-354, ST-403, and ST-443 complexes overlapped between isolates from patients and cattle, whereas ST-45 and ST-574 complexes overlapped between isolates from patients and poultry. All C. jejuni were resistant to at least one antibiotic. The highest resistance rate was toward ciprofloxacin (89.7%), followed by tetracycline (74.6%), and nalidixic acid (69.0%).</p><p><b>CONCLUSION</b>This is the first report of the genotypes and antibiotic resistance of C. jejuni in Shenzhen. Overlapping clonal complexes were found between isolates from patients and cattle, and between patients and poultry.</p>
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.