江苏某肉鸡屠宰场弯曲菌耐药性及aadE-sat4-aphA-3耐药基因簇分布分析

Antimicrobial resistance and distribution of aminoglycoside resistance gene cluster aadE-sat4-aphA-3 in Campylobacter isolates from a broiler slaughterhouse in Jiangsu province

为了解江苏某肉鸡屠宰场弯曲菌分离株耐药性及氨基糖苷类耐药基因簇aadE-sat4-aphA-3的分布特点,本研究采用药敏纸片法对肉鸡屠宰场117株弯曲菌分离株进行9大类26种抗生素的耐药性检测。结果显示,117株菌对链霉素和卡那霉素耐药的菌株占93.2%(109/117),对头孢氨苄耐药菌株占96.6%(113/117),对氟喹诺酮类药物耐药菌株占比均大于89.7%(105/117),对碳青霉烯类及氯霉素类药物较为敏感,且94%(110/117)的菌株表现出多重耐药性。采用PCR方法检测氨基糖苷类耐药基因簇aadE-sat4-aphA-3的分布情况。结果显示,有90株弯曲菌(空肠弯曲菌17、结肠弯曲菌73)检出了aadE-sat4-aphA-3耐药基因簇。进一步采用琼脂稀释法测定了其中20株aadEsat4-aphA-3阳性菌对氨基糖苷类5种药物的最小抑菌浓度(MIC)。结果显示,20株aadE-sat4-aphA-3基因簇阳性弯曲菌中共有12株对庆大霉素耐药,MIC值最高为256μg/mL,共有11株对受试的5种氨基糖苷类药物均耐药,且大部分菌株对阿米卡星、妥布霉素的MIC值≥256μg/mL。表明aadE-sat4-aphA-3基因簇阳性弯曲菌对氨基糖苷类药物有较强的耐药性。综上所述,江苏某肉鸡屠宰场弯曲菌对氟喹诺酮类及氨基糖苷类部分药物耐药性较高且多重耐药现象严重,空肠弯曲菌与结肠弯曲菌中均有aadE-sat4-aphA-3耐药基因簇分布,且部分该耐药基因簇阳性菌株对氨基糖苷类药物耐药性较强。本研究为畜禽养殖临床用药指导提供了参考依据,并为弯曲菌氨基糖苷类药物耐药机理的进一步研究奠定基础。

To investigate the antimicrobial susceptibility profiles of Campylobacter and the distribution of the aminoglycoside resistance gene cluster aadE-sat4-aphA-3 in the isolates from abroiler slaughterhouse in Jiangsu province, the susceptibility of 117 bacterias to 26 antibiotics belonged to 9 categories was determined by the Kirby-Bauer(K-B) method. The results showed that the resistant rates of the 117 isolates to kanamycin and streptomycin were 93.2%(109/117), and that of these isolates to cephalexin were 96.6%(113/117). The majority of the tested isolates were resistant to quinolones(>89.7%)(105/117) and less resistance was observed to carbapenems and chloramphenicols. About 94.0%(110/117) of the tested strains showed multidrug resistance. The distribution of the aadE-sat4-aphA-3 gene cluster was detected in the isolates by using PCR method. The aadE-sat4-aphA-3 gene cluster was positive in 90 strains(17 C. jejuni, 73 C. coli). The minimum inhibitory concentration(MIC) of the gene cluster positive isolates to 5 aminoglycoside antibiotics was further analyzed by agar dilution method. Among 20 isolates of aadE-sat4-aphA-3 gene cluster positive Campylobacter, 12 isolates were resistant to gentamicin and the highest MIC was 256 μg/mL. 11 isolates were resistant to 5 kinds of tested aminoglycoside drugs and most of the isolates were resistant to amikacin and to bramycin. The aadE-sat4-aphA-3 gene cluster positive Campylobacter was resistant to aminoglycosides. In conclusion, Campylobacter isolated from broiler slaughterhouse showed high resistant rates to aminoglycosides and fluoroquinolones and most of them exhibited multidrug resistance. The aadE-sat4-aphA-3 gene cluster was positive in both C. jejuni and C. coli. And part of the positive strains showed high resistance to aminoglycosides. This study provided information for clinical guidance of drug usage in livestock and poultry breeding and further investigation on the mechanism of aminoglycoside resistance of Campylobacter.