食品动物源沙门氏菌质粒介导喹诺酮类耐药基因的检测与分析

为了解食品动物源沙门氏菌质粒介导喹诺酮类耐药性(Plasmid-mediated quinolone resistance,PMQR),采用微量肉汤稀释法和PCR方法,检测了316株食品动物源沙门氏菌对20种抗菌药物的敏感性,以及菌株中PMQR基因的携带率.结果显示:316株沙门氏菌对20种抗菌药物呈不同程度的耐药性,95.57％菌株为多重耐药菌；316株菌中未检出qnrA、qnrC、qnrD、qnrS和qepA基因,7.91％菌株检出qnrB基因,15.19％菌株检出aac(6 ′ )-Ib-cr基因,7.91％菌株检出oqxA基因,8.86％菌株检出oqxB基因,这是首次在沙门氏菌中发现oqxAB基因;98.11％PMQR阳性菌同时携带2种及以上的耐药基因,呈8～17耐的多重耐药性,其中以qnrB和aac(6′)-Ibcr基因型为主；53株PMQR阳性菌分属于5种不同的基因型,耐药表型或耐药基因型不同的菌株却有相同的PFGE谱型.本次检测的316株食品动物源沙门氏菌耐药较为严重；菌株主要携带qnrB、aac(6 ′ )-Ib-cr及oqxAB基因；不同来源菌株存在同一耐药克隆株的流行.

Detection and Analysis of Plasmid-Mediated Quinolone Resistance Genes in Salmonella Isolates from Food Animals

To investigate the prevalence of plasmid-mediated quinolone resistance(PMQR) in Salmonella isolates from food animals,susceptibility of 316 Salmonella isolates from food animals to 20 antimicrobial agents were determined by the broth microdilution method,the prevalence of PMQR genes in the isolates were detected by PCR.The results showed that 316 Salmonella isolates exhibited different resistance to 20 antimicrobial agents,95.57% of isolates showed multi-resistance;The positive rates of qnrA,qnrC,qnrD,qnrS,qepA,qnrB,aac(6′)-Ib-cr,oqxA and oqxB genes were 0%,0%,0%,0%,0%,7.91%,15.19%,7.91% and 8.86%,respectively.oqxAB gene was the first time reported in Salmonella;98.11% of PMQR-positive strains,which showed multiple-resistance to 8-17 antimicrobials,harboured two or more resistant genes,qnrB & aac(6′)-Ib-cr was the most common in these strains;The results of PFGE displayed 53 PMQR-positive strains belonged to 5 PFGE patterns.Some strains,which had different resistant phenotype or genotype,showed same PFGE patterns.In conclusion,316 Salmonella isolates tested showed serious resistance to antimicrobial agents;qnrB,aac(6′)-Ib-cr and oqxAB genes were frequence in strains;Clonal strain was epidemic in some resistant isolates from different origins.