Distribution of aminoglycoside resistance gene cluster aadE-sat4-aphA-3 in 607 Campylobacter isolates from different sources in China

Objective To investigate the aminoglycoside resistance of Campylobacter isolated from different sources in China and the distribution of the aminoglycoside resistance gene cluster aadE-sat4-aphA-3 in the resistant isolates and the genotype of the resistant isolates. Methods Agar dilution method was used to analyze the minimum inhibitory concentration (MIC) of the isolates from different sources. The distribution of the aadE-sat4-aphA-3 gene cluster in streptomycin resistant Campylobacter isolates were detected by using PCR. Multilocus sequence typing was conducted to analyze the genotypes of the resistant isolates. Results Among 607 strains of Campylobacter isolated, 221 were streptomycin resistant (MIC 4 g/ml). The resistant rates of the isolates from diarrhea patients, chickens and pigs were 33.33%, 35.14% and 86.96%, respectively. The resistant rates of Campylobacter jejuni and Campylobacter coli were 14.37% and 67.46% respectively. The aadE-sat4-aphA-3 gene cluster was detected in 24 streptomycin resistant isolates (10.86%), in which 14 were from diarrhea patients, 4 were from chickens and 6 were from pigs. Among 100 streptomycin resistant isolates from different sources, 58 sequence types were detected, and ST 1464 was the most common sequence type. Conclusion The streptomycin resistant rate of C. coli was significantly higher than that of C. jejuni, and the resistant rate of Campylobacter isolated from pigs was higher than that of the isolates from diarrhea patients and chickens. The aadE-sat4-aphA-3 gene cluster was detected in both C. jejuni and C. coli.