肉鸡源多重耐药空肠、结肠弯曲菌的耐药分子特征

目的了解肉鸡源空肠和结肠弯曲菌的耐药谱特征,检测多重耐药菌株Ⅰ类整合子/基因盒、gyrA基因突变位点、tetO基因、23S rRNA突变位点的分子特征。方法利用PCR检测弯曲菌Ⅰ类整合子/基因盒的存在情况;利用MAMA PCR技术检测弯曲菌gyrA基因第257位碱基的突变情况;针对弯曲菌23S rRNA的V区2075突变位点检测突变菌株。结果多重耐药菌株占分离株的94.5%。146株多重耐药空肠和结肠弯曲菌中Ⅰ类整合子检出率为98.6%,有78株菌株检出3种基因盒,1 000 bp+750 bp+500 bp+250 bp为主要谱型,所占比例为92.3%;有131株在gyrA喹诺酮类耐药决定区发生突变,突变率为92.9%。127株四环素耐药弯曲菌tetO基因的检出率为95.3%。81株红霉素耐药菌株中,23S rRNA的V区2075处突变发生率为96.3%。结论空肠和结肠弯曲菌分离株携带aadA2耐药基因盒,与氨基糖苷类药物的耐药性相关;gyrA基因突变、tetO基因的携带以及23S rRNA突变,与弯曲菌对喹诺酮、四环素和大环内酯类耐药密切相关。

Molecular characteristics of multidrug resistant Campylobacter jejuni and Campylobacter coli isolated from broilers

Two hundred and ninety broiler originated isolates of Campylobacter jejuni and Campylobacter coli were examined for antimicrobial resistance against eight kinds of antimicrobial agents. Results indicated that multidrug resistant (MDR) strains occupied 94.5% of the isolates. A total of 146 isolates of MDR C. jejuni and C. coli were further researched for classⅠ integron and related cassettes, and the results indicated that 98.6% of the isolates harbored classⅠ integron; 78 isolates were positive for cassettes detection by PCR, 3 kinds of cassettes patterns were included and most (92.3%) of the isolates possessed 1 000 bp+750 bp+500 bp+250 bp cassettes, which was ascribed to aadA2 gene cassettes associated with resistance to aminoglycosides. The 92.9% of the quinolone resistant isolates had the Thr-86-Ile point mutation in gyrA at quinolone resistant determining region (QRDR), 95.3% of the tetracycline resistant isolates carried tetO gene, 96.3% of the erythromycin resistant isolates were found the A-2075-G mutation in V region of 23S rRNA, respectively. This study provided antimicrobial resistance information for the control and prevention of C. jejuni and C. coli, and also analyzed the underlying mechanism of resistances to quinolone, tetracycline and erythromycin.