哺乳母猪肠杆菌PMQR基因的检测

【目的】探讨广东集约化猪场哺乳母猪肠杆菌质粒介导喹诺酮类耐药(PMQR)基因的存在情况及其与Ⅰ类整合子的流行相关性。【方法】通过PCR测序对分离自哺乳母猪的74株大肠杆菌和20株沙门氏菌进行PMQR(qnrA,qnrB,qnrS,aac(6')-Ib-cr,qepA)基因检测。对PMQR基因阳性株进行Ⅰ类整合酶intⅠ基因PCR检测。采用琼脂平皿二倍稀释法测定PMQR阳性株对14种抗菌药物的MIC值。【结果】在94株被测菌中,共检出PMQR阳性菌14(14.9%)株,其中qnrB阳性菌2株,qnrS阳性菌11株,aac(6')-Ib-cr阳性菌4株,有1株沙门氏菌Salmonella14同时携带qnrB,qnrS,aac(6')-Ib-cr3种PMQR基因,1株大肠杆菌E.coli2同时携带qnrB和aac(6')-Ib-cr。qnrA和qepA未有检测出。14株PMQR阳性菌均携带Ⅰ类整合子且耐药性普遍较为严重。【结论】哺乳母猪源的肠杆菌存在PMQR基因的流行,且以qnrS的检出率为最高。Ⅰ类整合子与PMQR基因同时存在,是导致哺乳母猪肠杆菌多重耐药的重要因素。

Detection of Plasmid-Mediated Quinolone Resistance of Enterobacteria in Nursing Sow

Objective] To investigate the prevalence of the plasmid-mediated quinolone resistance PMQR genes and their molecule epidemiological relationship with class 1 integrons of nursing sow origin Enterobacteria in Guangdong Province. Method] Seventy-four Escherichia coli, 20 Salmonella were screened for the PMQR(qnrA, qnrB, qnrS, aac(6')-lb-cr, qepA) genes by PCR and then conformed with sequencing, intI Ⅰ was screened from the PMQR positive strains. Antimicrobial susceptibility tests for the PMQR positive strains were performed by the agar dilution method. Result] PMQR genes were detected in 14 (14.9%) of 94 strains, including 2 strains carried qnrB,11 strains carried qnrS, and 4 strains carried aac(6')-lb-cr gene. The strain Salmonella 14 harboured 3 PMQR genes (qnrB, qnrS and aac(6')-Ib-cr), and one E. coli 2 harboured qnrB and qnrS. qnrA and qepA were not detected, intI Ⅰ was detected in all the 14 PMQR positive strains and they showed high rate of resistance to antimicrobial agents widely used in veterinary medicine. Conclusion] The prevalence of PMQR genes existed from strains of Enterobacteria in nursing sow in Guangdong Province. And had a highest prevalence of qnrS was detected among Enterobacteria strains from the farms. The co-exist of class Ⅰ integron and PMQR genes played an important role in multi antimicrobial resistance in Enterobacteria.