土鸡屠宰过程中大肠杆菌毒力基因检测及耐药性分析

为了解土鸡屠宰过程中大肠杆菌污染、毒力基因携带及耐药情况,2018年9月-2019年1月在重庆万州、开州、巫溪、奉节4个区县的12个土鸡屠宰地点采集了319份样品,通过菌落形态及显微镜观察、生化鉴定、PCR、药敏试验等方法鉴定分离的大肠杆菌,检测其毒力基因携带和耐药性情况。结果表明：大肠杆菌分离率为22.57%（72/319）,其中餐馆、活禽宰杀铺和定点屠宰点分离率依次为29.73%（22/74）、25.00%（24/96）和17.45%（26/149）,污水、地面、羽毛、用具和胴体分离率依次为75.00%（18/24）、21.62%（8/37）、20.54%（23/112）、17.65%（6/34）和15.18%（17/112）;11种毒力基因中除estA、estB、elt外均被检出,检出率为58.33%（42/72）,共检出14种组合型,有4株分离株4种毒力基因同时存在;分离株对阿米卡星、头孢噻肟最敏感,多重耐药比为90.28%（65/72）,以7~10重耐药居多。土鸡屠宰过程中致病性大肠杆菌污染风险高,多重耐药现象严重,应重视养殖合理用药及屠宰卫生环境。     

陕西地区羊源致病性大肠杆菌耐药性分析与毒力基因检测

旨在了解陕西省部分地区腹泻羊源致病性大肠杆菌(E. coli)耐药性及毒力基因携带情况,本研究从10个养殖场采集54份腹泻羊拭子样品,经分离纯化、生化鉴定及16S rRNA基因序列分析,共分离得到50株E. coli,对分离菌进行药敏试验、耐药基因及毒力基因检测。结果显示,分离菌对氨苄西林、氟苯尼考和磺胺异噁唑耐药率达90%以上,且98%(49/50)为多重耐药菌,对8~11种抗生素耐药的菌株占68%(34/50),仅对美罗培南敏感。所有菌株均携带1~6种不同的耐药基因,其中,Sul1(64%)、TetA(34%)、bla_CTX-M(32%)携带率较高,未检测到bla_SHV。有5株产ESBLs的E. coli携带mcr-1耐药基因。毒力基因检测结果显示,98%(49/50)的菌株携带毒力基因,其中,etrA检出率最高,为80%(40/50)。综上表明,陕西省羊源E. coli多重耐药情况严峻,β-内酰胺类耐药基因与耐药表型不符,提示可能存在其他耐药机制,同时,分离菌具有复杂的毒力谱。本研究为陕西省羊源致病性E. coli感染的防控提供科学依据。     

辽宁地区奶牛乳房炎源大肠杆菌毒力基因及耐药基因检测分析

为了掌握辽宁地区规模奶牛场乳房炎源大肠杆菌携带的毒力基因和耐药基因,为奶牛养殖业提供更好的乳房炎防制方案,本研究采用PCR检测方法对辽宁地区多个规模奶牛场临床奶牛乳房炎奶样中分离的66株大肠杆菌进行了4种毒力基因和4种耐药基因的检测分析。结果发现,66株大肠杆菌中仅有1株未检出相关目的基因,其余65株中最少检出2种目的基因,最多检出7种目的基因。其中,毒力基因stx2e、eaeA、K99和astA的检出率分别为56.1%、47.0%、34.8%和31.8%,双重毒力基因的检出率达到43.9%,以eaeA/stx2e基因型的检出率最高;耐药基因sul3、sul1、cmlA及aacA4的检出率分别为87.9%、83.3%、40.9%和28.8%,双重耐药基因的检出率为36.4%,以sul1/sul3基因型检出率最高;三重耐药基因的检出率为37.9%,以cmlA/sul1/sul3检出率最高。本研究结果证实,辽宁地区奶牛乳房炎源大肠杆菌携带磺胺类耐药基因和氯霉素类耐药基因的比率较高,与大肠杆菌的耐药性有较直接的关系,该结果对于辽宁地区奶牛乳房炎的防制具有重要的指导意义,更具有重要的公共卫生意义。     

Detection and Analysis of Virulence Genes and Drug Resistance Genes in E. coli Strains Isolated from Dairy Cows with Clinical Mastitis in Liaoning Region

In order to understand the virulence genes and drug resistance genes carried by E.coli strains from dairy cows with mastitis in large-scale dairy farms in Liaoning region, and also provide improved programs for control and treatment of mastitis to dairy farmers, 66 strains of E.coli isolated from milk of dairy cows with clinical mastitis in several large-scale farms in Liaoning region were examined to detect 4 virulence genes and 4 drug resistance genes using PCR methods. The results showed that none of the target genes was detected in only one strain, while at least 2 and up to 7 target genes were detected in the rest of 65 strains. The detection rates of the virulence genes stx2e, eaeA, K99 and astA were 56.1%, 47.0%, 34.8% and 31.8%, respectively. In addition, the detection rate of dual virulence gene reached 43.9%, in which the genotype with the highest detection rate was eaeA/stx2e. The detection rates of the drug resistance genes sul3, sul1, cmlA and aacA4 were 87.9%, 83.3%, 40.9% and 28.8%, respectively. And the dual resistance gene detection rate was 36.4%, in which the highest detection rate was sul1/sul3 genotype; Triple drug resistance gene detection rate was 37.9%, and cmlA/sul1/sul3 presented the highest detection rate. These results confirmed that the E.coli isolated from dairy cow mastitis in large-scale dairy farms in Liaoning region had high detecting rates of sulfonamide resistance genes and chloramphenicol resistance genes, which was directly related to the drug resistance of the E.coli. These results provided important guiding significance for the prevention and control of dairy cow mastitis in Liaoning region as well as the safety of public health.     

双组分系统CpxR影响禽致病性大肠杆菌的耐药性、抗血清杀菌能力及毒力

CpxR是细菌中Cpx双组分系统（two component system,TCS）的反应调控蛋白,通过调控靶基因的转录表达,在细菌细胞膜稳定及毒力方面发挥作用。本研究旨在探究TCS CpxR对禽致病性大肠杆菌（avian pathogenic Escherichia coli,APEC）基本生物学特性、抗血清杀菌能力及致病性的影响。利用Red同源重组系统及互补质粒构建cpxR基因缺失株、互补株,然后比较分析野生株、基因缺失株与互补株的生长曲线、运动性、生物被膜形成能力、药物敏感性、抗血清杀菌能力、动物致病性的差异。结果显示：cpxR基因缺失株与野生株、互补株的生长速度和运动性能无明显差异,且缺失cpxR基因不影响APEC的生物被膜形成能力。然而,缺失CpxR导致APEC对阿米卡星和卡那霉素耐药性降低。血清杀菌试验结果显示,CpxR有助于APEC的抗血清杀菌能力。动物感染试验结果显示,野生株、cpxR基因缺失株和互补株对雏鸭的半数致死量（LD₅₀）分别为7.50×10⁵、7.50×10⁶、1.33×10⁶ CFU,表明CpxR缺失显著降低APEC的毒力。综上表明,TCS CpxR在APEC耐药性、抗血清杀菌能力及毒力方面发挥作用,为阐明APEC的环境适应性、生存能力及致病机制提供参考。     

Serotypes,Virulence Factors and Antibiotic Resistance of Duck Pathogenic Escherichia coli in Jiangsu Province and Its Surrounding Areas

In this study,191 strains of avian pathogenic Escherichia coli (APEC) were isolated from duck farms in and around Jiangsu province.The serotype,virulence gene distribution and drug resistance of 21 strains (one from each farm) were detected,and the correlation between serotype,virulence gene distribution and drug resistance was analyzed,in order to provide reference for the prevention and control of APEC.The serotypes of 21 APEC strains showed that there were 12 strains of O65,accounting for 57.14% of all strains.The results of virulence gene detection showed that 5 virulence genes had a high distribution rate,among which the positive rate of fimA gene was 100%,and the positive rates of ECs3737,ECs3703,tsh and irp2 genes were 90.5%,85.7%,57.1% and 42.9%,respectively.There were 6 strains (28.57%) with five virulence genes.The results of drug sensitivity test showed that 21 APEC strains had multiple drug resistance,and 100% strains were resistant to enrofloxacin,doxycycline,vancomycin and erythromycin.Among all the strains,85.71% and 14.29% were resistant to more than 10 and 21 kinds of drugs,respectively.The relationship among serotypes,virulence gene distribution and drug resistance showed that there were 13 strains with more than 4 virulence genes,9 of which were O65 serotypes.Among the 13 strains with more than 4 virulence genes,9 strains (69.23%) were resistant to more than 15 drugs,and 3 strains (23.08%) were resistant to more than 20 drugs.The results showed that the serotypes of Escherichia coli isolated from ducks in Jiangsu province and its surrounding areas were complex,carrying a variety of virulence genes,and the drug resistance was serious.     

江苏及周边地区鸭致病性大肠杆菌血清型、毒力因子及耐药研究

本研究旨在明确江苏及周边地区鸭禽致病性大肠杆菌（avian pathogenic Escherichia coli,APEC）的血清型、毒力基因分布和耐药性之间的相关性,以期为APEC的防控提供依据。从江苏省及周边养鸭场分离了191株APEC,并对其中21株（每个养殖场选取1株）的O抗原血清型、毒力基因分布和耐药性进行检测。对21株APEC的血清型检测结果表明,O65血清型12株,占全部菌株的57.14%,O5、O28、O42、O87、O93、O138、O147血清型均为1株,其他血清型2株;毒力基因检测结果表明,5个毒力基因有较高的分布率,其中fimA基因的阳性率为100%,ECs3737、ECs3703、tsh和irp2基因的阳性率分别为90.5%、85.7%、57.1%和42.9%,含有5个毒力基因的菌株共有6株（28.57%）;药敏试验结果表明,21株APEC均存在多重耐药性,100%的分离菌株对恩诺沙星、强力霉素、万古霉素和红霉素耐药,85.71%的分离株对10种以上抗生素耐药,14.29%的菌株对21种药物都耐药;对血清型、毒力基因分布和耐药性之间的关系分析表明,含有4种以上毒力基因的菌株有13株,其中9株是O65血清型。在13株含有4种以上毒力基因的菌株中,耐15种药物以上的有9株（69.23%）,耐20种以上药物的有3株（23.08%）,表明含有4种以上毒力基因的菌株多重耐药现象严重。研究表明,江苏及周边地区鸭源大肠杆菌血清型复杂,携带多种毒力基因,耐药性严重。     

广东省养禽场肠球菌耐药性及毒力因子流行分布特征

旨在调查和分析广东省养禽场肠球菌的亚型屎肠球菌和粪肠球菌耐药性及其毒力因子流行分布特征,为控制禽源肠球菌耐药性传播、保障公共卫生安全提供理论依据。作者于2018年从广东省4个养禽场采集肠道样品493份,进行屎肠球菌和粪肠球菌的分离鉴定;采用琼脂二倍稀释法测定肠球菌的最小抑菌浓度（MIC）;PCR方法检测肠球菌的耐药基因和毒力基因。结果显示：1）共分离到125株肠球菌,其中粪肠球菌84株（鸡源66株,鸭源18株）;屎肠球菌41株,均来自鸡肠道样本。2）菌株对四环素、多西环素、红霉素几乎全部耐药,对氟苯尼考和氯霉素的耐药率高达89.60%和74.40%。屎肠球菌耐药率普遍高于粪肠球菌,而粪肠球菌对环丙沙星和利奈唑胺的耐药率高于屎肠球菌;鸭源粪肠球菌对利奈唑胺的耐药率（94%）显著高于鸡源粪肠球菌（39.4%）,屎肠球菌对利奈唑胺均敏感。从鸡分离的1株粪肠球菌对万古霉素耐药。3）耐药基因在屎肠球菌中的检出率高于粪肠球菌,鸭源分离株检出率高于鸡源。耐药基因tetL、fexA、ermB最为流行,检出率均高于90%。其次是optrA基因,检出率为73.60%,poxtA和fexB的检出率均低于20%。在3株鸭源粪肠球菌中检测出cfr基因。4）已检测的毒力基因中efaA的携带率最高,为63.04%（58/92）,其他依次为gelE（54.35%,50/92）、ace（47.83%,44/92）、asa1（44.57%,41/92）。对环丙沙星及高浓度氨基糖苷类耐药的菌株及携带cfr基因的菌株,大多携带agg、asal、gelE或ace。本研究显示养殖场禽源肠球菌耐药严重,鸭源肠球菌对利奈唑胺耐药率高,耐药基因和毒力基因流行且多样,且检测出人医临床重要抗生素耐药基因,应加强对养禽场肠球菌耐药性监测。     

京津冀部分地区致犊牛腹泻大肠杆菌毒力基因、耐药基因检测及药物敏感性分析

【目的】探明京津冀地区犊牛腹泻大肠杆菌毒力基因与耐药基因流行情况,筛选敏感药物。【方法】于2020年12月至2021年7月从京津冀地区部分牛场采集146份犊牛腹泻样本,通过细菌分离纯化、革兰氏染色镜检及16S rRNA测序进行大肠杆菌分离鉴定;采用PCR方法对分离菌进行毒力基因（F17、K99、F41、STa、stx1、irp2和fyuA基因）和耐药基因（aac（6'）-Ⅰb、bla_CTX-M、bla_TEM、OqxB、tetA和sul1基因）检测;采用K-B纸片法进行药物敏感性试验。【结果】分离菌在鉴别培养基上的生长形态及革兰氏染色镜检结果均符合大肠杆菌生理生化特性,分离菌16S rRNA测序结果呈单一峰值,对拼接序列在NCBI中进行BLAST比对后发现,与大肠杆菌相似性均>96%,确定分离菌为大肠杆菌。试验共分离鉴定大肠杆菌142株,其中有88株携带毒力基因,占61.97%（88/142）,毒力基因F17、K99、F41、STa、stx1、irp2、fyuA阳性率分别为24.65%、0.70%、0、2.11%、1.41%、45.07%和21.83%,其中F17、irp2、fyuA为优势毒力因子,同时携带多重毒力因子的大肠杆菌检出率较低。aac（6'）-Ⅰb、bla_CTX-M、bla_TEM、OqxB、tetA和sul1 6种耐药基因皆被检出,bla_TEM基因检出率最高,为45.77%,aac（6'）-Ⅰb和OqxB基因检出率最低,均为9.15%,分离菌株主要携带1~3种耐药基因。药物敏感性试验结果显示,142株分离菌对诺氟沙星敏感率最高,其次为环丙沙星,对青霉素敏感率为0,耐药现象严重,耐2种以上抗菌药物的菌株达86.62%。【结论】京津冀地区犊牛腹泻大肠杆菌毒力基因与耐药基因流行广泛,耐药普遍,多重耐药现象严重。本研究可为京津冀地区犊牛腹泻的防治提供理论依据。     

牦牛隐性乳房炎主要病原菌及耐药和毒力基因分布情况

为探明牦牛隐性乳房炎（SCM）主要病原菌及其耐药和毒力基因的分布情况,本研究自甘肃省甘南州夏季牧场收集无乳房炎临床症状牦牛乳样,通过兰州乳房炎试验（LMT）筛选SCM乳样,从中分离病原菌并纯化培养,利用16S rDNA鉴定主要病原菌,通过纸片扩散法判定其药物敏感性,并采用PCR方法对相关耐药及毒力基因进行检测。结果显示,共筛选出牦牛SCM乳样324份,检出率14.43%;主要病原菌为葡萄球菌属、埃希氏菌属和肠球菌属,其中葡萄球菌分离株对青霉素和四环素耐药率最高,分别为59.57%和47.52%;大肠埃希氏菌分离株对四环素和氨苄西林耐药率最高,分别为43.40%和20.75%;粪肠球菌分离株对四环素和红霉素耐药率最高,分别为25.00%和16.67%;59株耐青霉素金黄色葡萄球菌中共检出MRSA 12株,其中7株携带mecA基因,5株含mecC基因;四环素外排泵基因tetK、tetA携带率最高（85.45%、56.36%）,核糖体保护基因tetM携带率最低（34.55%）;毒力基因中,clfA、clfB、fib、coa基因检出率较高（87.64%、84.27%、83.15%、82.02%）。研究表明,牦牛SCM的主要病原菌为金黄色葡萄球菌和大肠埃希氏菌,均对青霉素类和四环素类抗生素耐药性较高,其中金黄色葡萄球菌的主要毒力因子为黏附因子和凝固酶。     

马乳源大肠杆菌的毒力基因检测和耐药性分析

[目的] 了解新疆伊犁地区某马场乳源大肠杆菌的毒力基因携带情况和药物敏感性。[方法] 对采集到的85份马乳进行大肠杆菌的分离纯化、染色镜检、特异性基因phoA的扩增和16S rDNA测序;采用K-B纸片扩散法药敏试验分析马乳源大肠杆菌的耐药性;采用PCR技术检测马乳源大肠杆菌携带的毒力基因、耐药基因及鉴定其所属系统发育群,对大肠杆菌进行生物被膜形成能力检测。[结果] 从85份马乳中分离得到6株大肠杆菌,其中3株为A群,3株为B1群;6株大肠杆菌均对青霉素和替米考星耐药;均携带ibeB、yijP、mat、sodA和csgA毒力基因;均未检测到耐药基因;有4株具有生物膜形成能力。[结论] 对新疆伊犁地区某马场马乳源大肠杆菌进行初步的毒力基因检测和耐药性分析,发现其对青霉素和替米考星耐药严重,并携带多种毒力基因,具有一定的潜在致病风险。     

肉牛溶血性大肠埃希菌分离鉴定和毒力与耐药基因检测及药敏试验

为了解肉牛溶血性大肠埃希菌毒力基因和耐药基因分布情况及药物敏感性,从河北省围场县采集的健康肉牛鼻腔棉拭子中分离鉴定溶血性大肠埃希菌,采用PCR检测大肠埃希菌的4个毒力基因和12个耐药基因,并采用K-B法进行药敏试验。结果表明,从116份健康的肉牛鼻腔中分离鉴定出23株溶血性大肠埃希菌,分离率为19.8%;毒力基因检测结果显示,6株菌同时携带LEE(Ler、eaeA)毒力基因,携带率26.1%,18株同时携带高致病性毒力基因HPIirp2、fyuA,携带率78.3%,6株同时携带LEE和HPI毒力基因,携带率为26.1%;耐药基因检测结果显示,blaTEM、aadA1耐药基因的携带率最高,为100%;药敏试验结果显示,23株溶血性大肠埃希菌对头孢氨苄、复方新诺明、磺胺间甲氧嘧啶耐药。结果表明,溶血性大肠埃希菌普遍存在于健康肉牛鼻腔中,HPI毒力基因和β-内酰胺类和耐链霉素类耐药基因携带率高。对河北省围场县肉牛溶血性大肠埃希菌毒力基因和耐药基因进行了研究,并进行药物敏感性分析,结果提示溶血性大肠埃希菌对肉牛养殖存在潜在威胁。     

犬源大肠杆菌对氨基糖苷类药物耐药性及4种耐药基因的检测

为调查犬源大肠杆菌氨基糖苷类药物4种耐药基因的携带情况,探讨氨基糖苷类耐药表型与耐药基因的相关性,本试验选用氨基糖苷类代表药物庆大霉素、阿米卡星、大观霉素和妥布霉素进行药敏试验,参照相关文献用已建立的检测氨基糖苷类4种主要耐药基因的PCR方法对分离鉴定的156株犬源大肠杆菌进行分子检测。随机选取4种耐药基因阳性进行克隆测序并对药敏试验结果和耐药基因检测结果进行比较分析。结果显示,犬源大肠杆菌对庆大霉素、妥布霉素、大观霉素和阿米卡星的耐药率分别为55.8%、32.7%、25.0%和20.5%;所检大肠杆菌4种耐药基因aacC2、aphA3、aadA和aacC4的检出率依次为55.8%、26.3%、23.1%和9.0%。两株携带4种耐药基因,8株携带了3种耐药基因,携带两种或两种以上耐药基因菌株数占总菌株的40.4%(63/156)。序列分析结果表明,犬源大肠杆菌扩增产物与GenBank中的相应序列同源性较高。犬源大肠杆菌氨基糖苷类耐药基因以aacC2为主,耐药率与耐药基因的符合率基本呈正相关。     

Detection of Resistance to Aminoglycoside Antibiotics and Four Resistance Genes of Canine Escherichia coli

The objective of this paper was to investigate the drug resistance of canine Escherichia coli (E.coli) strains and the carrying rates of four resistance genes,and explore the relationship between resistance phenotypes and resistance genes.This article chose the aminoglycoside antibiotics including gentamicin,amikacin,spectinomycin and tobramycin to carry out the antibiotics sensitivity test.According to the established PCR assays,we detected the molecular characteristics of the 156 strains of isolates.The positive fragments of four kinds of resistance genes were cloned and sequenced,and the relationships between antibiotics sensitivity test and the resistance genes were analyzed.The results showed that the resistance rates of canine E.coli strains to gentamycin,tobramycin,spectinomycin and amikacin were 55.8%,32.7%,25.0% and 20.5%,respectively.The detection rates of resistance genes aacC2,aphA3, aadA and aacC4 were 55.8%,26.3%,23.1% and 9.0%,respectively.Two strains carried all four kinds of resistance genes,eight strains carried two kinds of resistance genes,and the strains carried two or more resistance genes accounted for 40.4% (63/156).The sequence analysis showed that the amplified gene fragments had higher homology compared with the sequences from GenBank.The main resistance gene in canine E.coli was aacC2 and there was a positive correlation between resistance rates and resistance genes compliance rate.     

Occurrence of genes encoding aminoglycoside-modifying enzymes in Escherichia coli isolates from chicken meat

ABSTRACT

1. The aim of the experiment was to determine the occurrence of genes encoding aminoglycoside-modifying enzymes (AMEs) in Escherichia coli isolates recovered from chicken meat.

2. Antibiotic sensitivity was tested using the disc diffusion test. AMEs and virulence profile were determined by PCR/sequencing.

3. Out of 195 meat samples collected, 185 (95%) isolates were identified as E. coli. Disc diffusion showed a resistance value of 22% (n = 42) for at least one of the antibiotic aminoglycosides (AGs) tested (tobramycin, gentamycin, amikacin and kanamycin). PCR screening showed the presence of three classes of AMEs, namely, aac(3)-II (12%), aac(6?)-Ib (7%) and aac(2?)-Ia (5%). Eight of the 42 isolates were positive for the stx₁ and sxt₂ genes and were defined as Shiga toxin-producing E coli., while the eae gene was positive in one strain. Among the 42 isolates, group A was the predominant phylogenetic identified (76%), followed by group D (21%). One isolate belonged to subgroup B2₃.

4. The results suggested that chicken meat could be an important reservoir of AMEs, and pose a potential risk by dissemination of resistance to humans through the food chain.     

我国猪源和鸡源大肠杆菌抗生素耐药性相关基因研究进展

大肠杆菌作为一种条件致病菌和重要的耐药性指示菌,国内外已有大量猪源、鸡源大肠杆菌耐药性相关基因的研究报道.受动物种属、地域等来源性差异,以及耐药机制、亚型等因素的影响,研究中涉及很多种不同的耐药性相关基因,且检出率也不尽相同.根据耐受抗菌药物种类,对这些基因作用机理及分布情况等方面综述,以期为研究大肠杆菌耐药性产生机制...     

奶牛乳房炎源大肠埃希氏菌的耐药性分析和毒力基因检测

为了解奶牛乳房炎大肠埃希氏菌耐药性、毒力基因携带及分布情况,从2019年9月至2020年6月在新疆乌鲁木齐、伊犁、昌吉地区的7个奶牛场共采集了142份乳房炎奶牛牛乳样本,采用麦康凯培养基和伊红美蓝培养基进行筛选,利用生化试验和16S rDNA PCR方法鉴定出大肠埃希氏菌,用K-B纸片扩散法对分离株进行耐药性检测,PC...     

广西罗非鱼无乳链球菌的分离鉴定、毒力基因及耐药性研究

本研究旨在明确中国罗非鱼主养区广西各地罗非鱼无乳链球菌（Streptococcus agalactiae）分离株的血清型分布、毒力基因携带情况和耐药情况,为罗非鱼无乳链球菌病的防控奠定基础。2018-2019年从广西柳州、钦州、南宁、北海等地患无乳链球菌病罗非鱼体内分离了47株无乳链球菌,并对各分离株的血清型、毒力基因分布和耐药情况进行检测和分析。血清型检测结果表明,47株无乳链球菌血清型高度一致,均为Ⅰa血清型。对4种毒力基因检测结果表明,47株无乳链球菌临床分离株cylE、sodA、gapC毒力基因的检出率均为100%,而scpB基因仅在人源参考菌株2603V/R中检出,在所有鱼源分离株中未检出。对11类（31种）常见抗生素的药敏试验结果表明,临床分离株对磺胺异噁唑、新霉素、庆大霉素、卡那霉素的耐药率达到90%以上,对氧氟沙星、左氧氟沙星、氨苄青霉素、阿莫西林、头孢克洛、头孢曲松、头孢哌酮、头孢拉定、土霉素、强力霉素的敏感性均为100%。多重耐药检测结果表明,5重以上耐药菌株占93.62%,其中9重以上耐药菌株为19.15%,且均分离自柳州地区。结果表明,广西地区罗非鱼源无乳链球菌血清型单一,均为Ⅰa血清型,且均携带多种毒力基因,多重耐药现象严重。     

鸡源大肠杆菌强毒株耐药基因的定位及耐药质粒消除

本试验对临床分离的多重耐药鸡源致病性大肠杆菌强毒株的耐药基因进行初步定位,为临床选择合适的治疗策略提供理论依据。从送检病死鸡的肝脏、心脏中分离鉴定致病菌,质粒提取试剂盒提取分离菌的耐药质粒,转化入基因工程菌JM109,通过质粒纯化、电泳和药敏试验对耐药基因进行了初步定位。并用艾叶水煮液对该菌株进行体外耐药质粒消除试验。结果分离鉴定到1株强毒力鸡源大肠杆菌,该菌呈多重耐药性,且仅对氟奇霉素和链霉素敏感;由质粒转化和药敏试验结果可初步将耐环丙沙星、青霉素、氧氟沙星、氟哌酸、林可霉素和复方新诺明的基因定位于耐药质粒上,并可随质粒的转移而使转化菌获得耐药性;用艾叶水煮液可使该菌的耐药质粒消除率达60%;质粒消除菌的药敏试验结果表明,消除耐药质粒的细菌恢复了对环丙沙星、青霉素、氧氟沙星、氟哌酸、林可霉素和复方新诺明的敏感性。本研究结果表明,分离菌的耐药基因分别位于质粒和染色体上,艾叶对耐药质粒有较强的消除作用,可作为临床治疗用药。     

牛源大肠杆菌质粒介导喹诺酮类耐药基因的检测分析

为研究近年来新疆地区牛源大肠杆菌中质粒介导喹诺酮类药物耐药基因的分布及其对喹诺酮类抗生素的耐药情况,本研究于2016-2018年从新疆石河子、沙湾、奎屯、玛纳斯和伊犁5个地区12个规模化奶牛场分离出116株牛源大肠杆菌,药敏试验检测其耐药性,同时利用PCR扩增PMQR耐药基因。药敏试验结果显示,62.93%的菌株对氨苄西林耐药,耐药率最高。对链霉素、四环素、卡那霉素和恩诺沙星的耐药率依次为56.90%、54.31%、43.10%和42.24%。对头孢他啶和头孢噻肟的耐药率较低,分别为7.76%和11.21%。分离菌主要携带qnrA、qnrS和aac（6'）-Ⅰb-cr 3种耐药基因;116株大肠杆菌中有31株携带PMQR的耐药基因,检出阳性率为26.72%,其中26株仅携带1种PMQR耐药基因,占所有菌株的22.41%,4株携带2种PMQR耐药基因,占所有菌株的3.45%,1株携带3种PMQR耐药基因,占所有菌株的0.86%。综上所述,新疆地区牛源大肠杆菌质粒介导喹诺酮类药物基因主要为qnrA、qnrS和aac（6'）-Ⅰb-cr 3种,且对恩诺沙星、诺氟沙星、环丙沙星、左氧氟沙星均产生不同程度的耐药性。