湖南省部分地区猪、鸡源粪肠球菌耐药性及多位点序列分型分析

DRUG RESISTANCE AND MULTI-LOCUS SEQUENCE TYPING OF ENTEROCOCCUS FAECALIS STRAINS ISOLATED FROM PIGS AND CHICKENS IN HUNAN PROVINCE

为探究湖南省不同地区猪、鸡源粪肠球菌耐药特征,多重耐药株的流行性和多位点序列的分型,本研究采用微量肉汤稀释法对81株分离的粪肠球菌进行8种抗菌药物的耐药性检测,应用MLST方法对部分多重耐药菌株进行分型。结果显示,分离株对红霉素、四环素以及头孢西丁严重耐药,耐药率均在90%以上,对氧氟沙星和氟苯尼考的耐药相对严重,耐药率为60%~80%,仅有1株对万古霉素耐药;本次试验中有75株粪肠球菌对3种及3种以上药物耐药,多重耐药率达92.6%;35株多重耐药粪肠球菌共有21个MLST型,其中CC(Clonal complex)16、CC480、CC476、CC4为优势克隆群。CC16所覆盖的粪肠球菌数量最多,占比28.6%。比较4个优势CC群耐药性,所有菌株均对四环素、红霉素及头孢菌素耐药,2株ST16型菌株的多重耐药谱完全相同,2株ST480菌株的耐药谱仅存在1处差异。结果表明,不同地区猪、鸡源粪肠球菌分离株有着丰富的ST型,同一种ST型的菌株可能具有相同或相似的多重耐药谱。

The objectives of the present study were to gain more knowledge of the drug resistant characteristics of 81 Enterococcus faecalis strains isolated from pigs and chickens in different regions of Hunan province,prevalence of multi-drug resistant isolates and multi-site sequence types.These strains were tested using the microdilution broth method for their drug resistance to 8 antibiotics and MLST method to further classify those multi-drug resistant strains.The results showed that 90%tested strains were highly resistant to erythromycin,tetracycline and cefoxitin,and 60%to 80%strains were resistant to ofloxacin and florfenicol.Only one strain was resistant to vancomycin.Among them,75(92.6%)strains were resistant to 3 or more drugs.There were 21 MLST types identified from 35 multidrug resistant strains,among which CC(clonal complex)16,CC480,CC476 and CC4 were dominant clone groups.CC16 accounted for the largest number(28.6%)of these strains.As compared with drug resistance of 4 dominant CC groups,all strains were resistant to tetracycline,erythromycin and cephalosporin.In addition,two ST16 strains sowed the same multi-drug resistance spectrums and two ST480 strains had one difference only.These results indicated that the abundant ST types existed among Enterococcus faecalis strains from pigs and chickens in different regions and the same types of strains might have the same or similar multi-drug resistance spectrums.