水貂源致病性大肠杆菌生物被膜形成能力、耐药性及毒力岛基因检测与分析

Detection and analysis of biofilm formation ability,antimicrobial-resistance and pathogenic island gene of pathogenic Escherichia coli isolated from minks

为探索水貂肠道致病性大肠杆菌(E.coli)生物被膜(BF)形成能力、耐药性、毒力岛基因分布及其之间可能存在的相关性,本研究对收集的临床分离鉴定的54株致病性E.coli,采用结晶紫染色定量法测定体外BF形成能力,K-B法药敏试验检测对10种常见抗菌药物的敏感性,PCR检测毒力岛代表基因。结果显示,54株E.coli BF形成阳性率为90.7%,以强阳性为主;分离株对氨苄西林、环丙沙星、青霉素和四环素的耐药率分别为100%、97.5%、92.5%和90%,对多黏菌素B的耐药率最低为17.5%,多数菌株呈现多重耐药,其中对6种以上抗菌药物耐药的占92.6%。毒力岛基因irp2和eae阳性率均为7.4%,未检测到SGI基因。这些分离株普遍具有较强BF形成能力,并呈现多重耐药性,BF形成能力与菌株对呋喃妥因、环丙沙星及氟苯尼考的耐药性呈正相关,但未发现和毒力基因分布率存在明显相关性。

To investigate the ability of biofilm formation, antimicrobial-resistance and pathogenic island gene of pathogenic Eschcrichia coil isolated from minks, a total of 54 E.coli were isolated and identified including the detection of biofilm formation ability, antimicrobial resistance and the genes associated to pathogenic island, the results shown that 90.7% （49/54） of E.coli isolates were able to formthe biofilm, of which the abilityof biofilm formation were strong in 44 isolates （81.5%）, medium in 4 isolates （7.4%） and weak in 1 isolate （1.9%）. In addition, the isolates displayed resistance to ampicillin （100%）, ciprofloxacin （97.5%）, penicillin （92.5%）, tetracycline （90%）. The lowest resistance rate to polymixin B was 17.5%. Most of the isolate showed multiple-drug resistance phenotype, and 92.6% of the isolates were resistant to more than 6 drugs. The positive rate of irp and eae virulent genes among the isolates was 7.4% and no SGI gene was detected. The results also revealed that the isolates had a high percentage of biofilm-forming phenotypes and multiple-drug resistance, and drug resistance tofuradantin, ciprofloxaein and florfenicol was positively correlated to the biofilm formation ability. However, the presence of irp2, eae and SGI is not associated with the biofilm formation abilityamong the isolates.