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1.
我国鸡源大肠杆菌喹诺酮耐药株中qnr基因的发现   总被引:1,自引:0,他引:1  
本文从我国鸡源大肠杆菌质粒中发现了介导喹诺酮类耐药的qnr基因。从120株鸡源大肠杆菌分离株中筛选出17株喹诺酮类耐药菌,以其质粒提取物为模板,PCR扩增介导喹诺酮类药物耐药qnr基因,结果发现3株阳性菌。序列测定结果显示,3株菌间qnr同源性为100%,与GenBank注册序列(AY655485)同源性为95.3%,氨基酸序列同源性为98.63%。3株qnr阳性菌对16~19种抗菌药物呈高水平多重耐药。  相似文献   

2.
为了考察徐州地区猪源致病性大肠杆菌的耐药情况,采用传统微生物法对徐州周边地区52株猪大肠杆菌进行分离鉴定,试管二倍稀释法测定细菌对药物的敏感性,提取耐药菌质粒DNA,PCR扩增耐药基因目的片段。结果表明,氟苯尼考和阿莫西林对徐州周边临床大肠杆菌分离株的最小抑菌浓度(MIC)值与标准菌株相比较,分别提高20~512倍、10~800倍,个别临床分离株对恩诺沙星的MIC值高达80μg/mL,对头孢曲松的MIC值高达80μg/mL,对安普霉素的MIC值高达320μg/mL;经PCR检测临床分离株均扩增出氟苯尼考Flor耐药基因,Tem型ESBLs耐药基因目的片段。说明徐州周边临床大肠杆菌对氟苯尼考和阿莫西林已产生严重耐药性,对恩诺沙星和安普霉素已经耐药,但大部分菌株对头孢曲松敏感。提示徐州周边地区猪场应科学合理、有计划地轮换使用不同药物。  相似文献   

3.
应用氟喹诺酮类药物对若干株大肠杆菌进行体外药敏试验。结果:百病消、普杀平、恩诺沙星对大肠杆菌O2株的最小抑菌浓度(MIC)分别为1 μg/mL、2μg/mL、2μg/mL、最小杀菌浓度(MBC)分别为2μg/mL、4μg/mL、4μg/mL;新配恩诺沙星溶液和室温放置1月后的恩诺沙星溶液对大肠杆菌O2的MIC分别为2μg/mL、4μg/mL、4μg/mL;MBC为4μg/mL、8μg/mL。同时进行的纸片法测定结果表明:O1株、O2株,敏感性感高。而O78株和乌苏分离株具有耐药性。  相似文献   

4.
为了解淄博地区鸡源耐氟喹诺酮大肠杆菌的耐药特点及其耐药基因携带特点。本研究于2016年5月对淄博地区两个鸡场粪便棉拭子采集,分离耐头孢噻肟大肠杆菌,并对15种抗生素进行药敏检测。PCR检测qnr A、qnr B、qnr S、aac-(6’)-Ib-cr耐药基因。共收集34份粪便棉拭子,分离14株耐喹诺酮大肠杆菌,分离率47%。所有耐喹诺酮大肠杆菌呈现多重耐药,但都对碳青霉烯类药物敏感。12株菌携带qnr S基因,携带率最高为85.7%。鸡源耐喹诺酮大肠杆菌分离率高耐药谱广,给临床中应用抗生素的治疗带来困难。  相似文献   

5.
【目的】 研究纳米银(silver nanoparticles,AgNPs)对多重耐药猪链球菌(Streptococcus suis,S.suis)的体外抗菌活性及其生物膜形成的影响,为解决猪链球菌的耐药问题提供参考。【方法】 以5株临床分离的多重耐药猪链球菌(S1018、S894、S786、S815和S844)为研究对象,采用微量肉汤稀释法测定AgNPs对5株猪链球菌的最小抑菌浓度(minimum inhibitory concentration,MIC)和最小杀菌浓度(minimum bactericidal concentration,MBC),通过测定AgNPs作用下细菌的生长速率以及不同浓度AgNPs对猪链球菌的抑制率来评价AgNPs的抗菌活性;通过结晶紫染色法测定各菌株生物膜的形成能力和6.25、12.5、25、50 μg/mL AgNPs对5株多重耐药猪链球菌菌株生物膜形成的影响。【结果】 AgNPs对S1018株的MIC和MBC均为12.5 μg/mL,对其余4株多重耐药猪链球菌的MIC和MBC均为25.0 μg/mL;AgNPs对多重耐药猪链球菌的抗菌活性好,25~100 μg/mL AgNPs对5株菌的抑制率可以达到96.60%~99.70%,在1/2MIC、1MIC和2MIC AgNPs作用下细菌生长速率明显受到抑制。5株多重耐药猪链球菌均能形成生物膜,6.25、12.5、25、50 μg/mL AgNPs对5株多重耐药猪链球菌菌株生物膜形成的抑制率为17.98%~45.58%。【结论】 AgNPs对多重耐药猪链球菌的活性和生物膜形成均具有抑制作用。  相似文献   

6.
为研究近年来山东省肉鸭源致病性大肠杆菌对喹诺酮类药物的耐药性,本研究将2010年以来分离自山东省潍坊市发病肉鸭的232株大肠杆菌进行了洛美沙星、培氟沙星、氧氟沙星、诺氟沙星等4种喹诺酮类药物的药敏试验,并对其进行了质粒介导喹诺酮类药物耐药基因的PCR检测。结果表明,山东省潍坊市肉鸭源大肠杆菌对4种喹诺酮类抗生素均产生了较高耐药性(54.31%~82.760%),质粒介导喹诺酮类耐药(PMQR)基因携带率达到58.19%(135/232),26.29%(61/232)的菌株携带两种产PMQR基因,1.72%(4/232)的菌株携带三种PMQR基因。未检测到qnr A、qnr B、qnr C、qnr D与Qep A基因,qnr S、oqx A和oqx B基因在山东省禽源致病性大肠杆菌中分布较为广泛,其检出率依次为19.83%(46/232)、41.81%(97/232)和26.29%(61/232)。  相似文献   

7.
为了了解内蒙古地区腹泻犊牛中大肠杆菌的污染状况、耐药情况及蒲公英水煎液对多重耐药大肠杆菌耐药性的消除作用。本试验采用革兰染色、生化试验和PCR方法对采集到的107份犊牛源病料进行大肠杆菌的分离和鉴定,采用K-B法检测分离菌株对18种抗菌药物的敏感性,采用PCR方法进行8种耐药基因的检测,采用琼脂稀释法测定蒲公英水煎液对分离菌株的最小抑菌浓度(MIC),通过将菌株与蒲公英水煎液作用后进行耐药消除试验。结果显示,从107份病料中分离鉴定出44株犊牛源大肠杆菌,分离率为41%;大肠杆菌分离株对氨苄西林、头孢噻吩、头孢噻肟、环丙沙星和左氧氟沙星5种抗菌药物的耐药率均达到50%以上;β-内酰胺类耐药基因中blaCTX-M基因携带率为86%,喹诺酮类耐药基因中qnr(S)基因携带率为32%;蒲公英水煎液对筛选出的耐药菌株的MIC为200 mg/mL;经蒲公英水煎液处理后的大肠杆菌对抗菌药物的敏感性增强,而且更不容易出现耐药。结果表明,内蒙古地区腹泻犊牛中大肠杆菌的耐药情况严重,而蒲公英水煎液对大肠杆菌的多重耐药有一定的消除作用,可降低临床应用抗菌药物的耐药性,增加临床疗效,本...  相似文献   

8.
为了有效地治疗鸡大肠杆菌病,采用微量倍比稀释方法测定了17种抗菌药物对临床分离的豫北地区15株鸡大肠杆菌的体外最小抑菌浓度(MIC),并根据其MIC及MIC范围(MICRange)使用SPSS 13.0中Probit过程计算出17种抗菌药物的MIC50和MIC90.结果表明:多粘菌素B的抑菌作用最强,MIC50、MIC90分别为0.11、0.87 μg/mL;加替沙星的抑菌作用次之,MIC50、MIC90分别为2.53、3.88 μg/mL,其它3种药物恩诺沙星、左氧氟沙星、环丙沙星的抑菌作用相当,但不及加替沙星,MIC50、MIC90分别为10.11~11.79 μg/mL、15.16~21.13 μg/mL;多西环素和阿莫西林等12种抗菌药物的抑菌作用较小,MIC50、MIC90分别为18.53~388.50 μg/mL和30.59~713.42 μg/mL.  相似文献   

9.
头孢噻呋与恩诺沙星联用体外抗菌活性研究   总被引:1,自引:0,他引:1  
采用两倍稀释法、棋盘法测定头孢噻呋、恩诺沙星以及两者联用对鸡大肠杆菌标准株、临床分离株和鸡链球菌标准株、临床分离株的最小抑菌浓度(MIC)值。结果显示:单方头孢噻呋对五菌株的MIC值介于1~32μg/ml之间,恩诺沙星的MIC值介于0.5~64μg/ml之间,且两药对临床分离株的抗菌活性均明显较标准株低。两药联用对鸡大肠杆菌标准株和临床分离不产酶株、鸡链球菌标准株的部分抑菌浓度(FIC)指数均为0.75,呈现相加作用;对鸡大肠杆菌临床分离产酶株和鸡链球菌临床分离株的FIC指数为1.5,呈现无关作用,但头孢噻呋联用MIC值仅为单方的1/2。  相似文献   

10.
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。  相似文献   

11.
The aim of this study were to detect the gyrA, parC and marR mutations and qnr genes (qnrA, qnrB and qnrS) in 120 strains of Escherichia coli isolated from animals. European Committee on Antimicrobial Susceptibility Testing and Clinical Laboratory Standards Institute disc diffusion and minimum inhibitory concentration (MIC) tests, respectively, were used to determine fluoroquinolone (FQ) resistance, and molecular methods were used to detect the mutations and the genes. E coli isolates with an MIC of ≥8 mg/l had mutation at Ser-80 in parC in addition to mutations at Ser-83, Asp-87 or both in gyrA. The nucleotide change was detected in marR (Ser-3?→?Asn, Ala-53?→?Glu, Gly-103?→?Ser, Tyr-137?→?His). Only four E coli isolates (3.3 per cent) contained qnrA and qnrS, and qnrB was not detected. Two E coli isolates from healthy calves also contained qnrA and qnrS. The MICs of enrofloxacin and danofloxacin for qnr-containing E coli isolates ranged from 32 mg/l to 256 mg/l. The results of this study indicated that the FQ-resistant E coli isolates presented an alteration in gyrA (Ser-83?→?Leu, Asp-87?→?Asn) and parC (Ser-80?→?Ile) with high MICs (8-256 mg/l), and there was a low prevalence of qnr genes among E coli isolated from animals.  相似文献   

12.
The prevalence of qnr genes was investigated in veterinary clinical isolates of Escherichia coli in Guangdong province, China, and the aac (6')-Ib gene and the mutations in QRDRs of gyrase and topoisomerase IV were examined in qnr-positive strains. A total of 232 E. coli strains isolated from pig and poultry were screened for the presence of the qnrA, qnrB and qnrS genes by PCR and sequencing. The aac (6')-Ib gene was detected in qnr-bearing strains by PCR and sequencing. For all strains carrying qnr, MICs for six quinolones were determined. Mutations within the gyrase and topoisomerase were analyzed by PCR and sequencing for all the QRDRs of gyrA, gyrB, parC and parE. Among 232 E. coli isolates, 14 (6%) isolates were positive for the qnr gene, including one for qnrB, 13 for qnrS, but no qnrA was identified in this population. Detection of the aac (6')-Ib gene showed that one qnrS-positive isolate from pig and one qnrB-positive isolate from duck carried aac (6')-Ib gene, and both were the cr variant allele of aac (6')-Ib. All of the 14 isolates had MICs of ciprofloxacin more than 0.25 mg/L. Mutations in the QRDR of gyrA mutations were observed in 5 (35.7%) of the 14 strains. Three fluoroquinolone-resisting strains showed one mutation S83L of gyrA, while one S83I. One high-level resistance strains harboured gyrA S83L and A87N of gyrA. A singe mutation in site 58 of parC was detected in 3 (21.4%) strains. None mutations were found in QRDRs of gyrB and parE. The emergence of qnr genes in veterinary clinical E. coli isolates is described for the first time. This is also the first report of aac (6')-Ib-cr gene in E. coli isolates from food-producing animals.  相似文献   

13.
Eighty-seven Streptococcus suis isolates recovered in 1999-2000 from diseased pigs, all from different farms, were screened for resistance against macrolide and lincosamide antibiotics by the disk diffusion and agar dilution test and a PCR assay, amplifying the ermB gene and the mefA/E gene. Seventy-one percent of the isolates showed constitutive resistance to macrolide and lincosamide antibiotics (MLS(B)-phenotype). All these isolates were positive for the ermB gene in the PCR, but negative for the mefA/E gene. For all strains minimum inhibitory concentrations (MIC) against five other antimicrobial agents were determined. All strains were susceptible to penicillin. Ninety-nine percent of the isolates were susceptible to enrofloxacin and tiamulin. Eighty-five percent of the strains were resistant to doxycycline. A 540bp fragment of the ermB genes of eight S. suis strains was sequenced and compared with ermB genes of five S. pneumoniae and five S. pyogenes strains of human origin. A 100% homology was found between these fragments in seven S. suis, one S. pneumoniae and three of the S. pyogenes isolates. This study demonstrates that resistance against macrolides, lincosamides and streptogramin B is widespread in S. suis and mediated by ribosome methylation, encoded by the ermB gene.  相似文献   

14.
This study examined and compared the minimal inhibition concentrations (MICs) of enrofloxacin against 393 Staphylococcus intermedius strains isolated in France from canine pyodermas during three different years, 1995 (174 isolates), 1997 (101 isolates) and 1999 (118 isolates). The MICs of enrofloxacin against these strains ranged from 0.063 to 64 mg L?1, with MIC50 and MIC90 equal to 0.125 and 0.25 mg L?1, respectively. Two resistant strains were found, but only among isolates collected in 1999. The data show that resistance to enrofloxacin among S. intermedius strains is still rare in dogs, but the selection in vitro of variants in which the MICs were increased 4–16‐fold after 10 serial passages in subinhibitory concentrations of enrofloxacin suggests that inappropriate use might favour the development of resistant strains in vivo.  相似文献   

15.
The purpose of the present study was to determine the prevalence of antibiotic resistance, with special attention to vancomycin, in 104 strains of Enterococcus, which is the sentinel bacterium isolated from dog and cat faeces samples. The phenotypic characterization of the isolates classified them as E. faecium (58%), E. avium (41%) and E. faecalis (1%). Sensitivity testing used the diffusion method according to the recommendations of CASFM (Comite de l'Antibiogramme de la Société Fran?aise de Microbiogie), to oxacillin, amoxycillin, amoxycilin + clavulanic acid, ampicillin, piperacillin, cefoperazone, imipenem, enrofloxacin, ciprofloxacin, ofloxacin, nalidixic acid, tetracycline, lincomycin, erythromicin and vancomycin. Minimum inhibitory concentration (MIC) determination by E test revealed a MIC to vancomycin of between 0.5 microg/ml and 3 microg/ml. All the strains were resistant to nalidixic acid, erythromycin, cefoperazone and oxacillin. We detected resistance to amoxycillin + clavulanic acid in 1.9% of isolates, to amoxycillin in 4.8%, to piperacillin in 13.5%, and to ampicillin in 21.2% of strains. A high prevalence of antibiotic resistance to lincomycin, tetracycline, enrofloxacin, ciprofloxacin and ofloxacin was found in 98.1%, 95.2%, 76.9%, 73.1% and 64.4% of strains, respectively. Resistance to vancomycin was not found, which indicates that there is no transmission risk of vancomycin-resistant enterococcal strains to man or transfer of their resistance genes to other bacteria belonging to the endogenous flora of humans.  相似文献   

16.
为了分析四川地区牦牛源肺炎克雷伯氏菌耐药性并确定其耐药基因的携带情况,本试验采集了四川地区不同养殖场患呼吸道疾病牦牛肺脏、咽拭子、鼻拭子共127份病料组织,分离得到了43株肺炎克雷伯氏菌,并采用微量肉汤稀释法结合PCR扩增法检测43株肺炎克雷伯氏菌的耐药性和耐药基因携带情况。结果表明:43株肺炎克雷伯氏菌对氨苄西林、阿莫西林、多西环素、磺胺间甲氧嘧啶4种药物耐药率较高,为65.12%~90.70%;对阿米卡星、氟苯尼考、多黏菌素B、大观霉素4种药物的耐药率在20.93%~48.84%之间;对头孢噻呋、恩诺沙星、环丙沙星3药物的耐药率在18.60%~25.58%之间;多数筛选分离得到的菌株均呈现出多重耐药性,耐9、10种药物的菌株最多,分别占分离菌株的23.3%和20.9%。通过使用PCR扩增法检测分离菌携带的耐药基因情况,结果表明:blaTEM、blaSHV、sul2、sul3、floR 5种耐药基因检出率较高,检出率在62.8%~69.8%之间;ant (3″)-Ⅰa、aph (3')-Ⅱa、aac (6')-Ⅰb、aacC2 4种耐药基因检出率较低,检出率在7.0%~20.9%;blaCTX-M、Mcr-1、qnrA、qnrS、rmtB 5种耐药基因未检出。综上所述,本试验中分离得到肺炎克雷伯氏菌具有较强的耐药性并携带有较多的耐药基因,为了更好的促进四川省牦牛养殖产业的发展,应注意避免滥用抗生素并通过药敏试验对症下药。  相似文献   

17.
OBJECTIVE: To investigate the development of enrofloxacin resistance among Escherichia coli isolates obtained from chickens by determining mutant-prevention concentrations (MPCs) and sequence the quinolone resistance-determining regions (QRDRs) of gyrA and parC genes in selected isolates. SAMPLE POPULATION: 15 chicken-derived E coli isolates. PROCEDURES: For all isolates, MPC and minimal inhibition concentration (MIC) of enrofloxacin were determined. The MPCs and maximum serum drug concentrations attained with enrofloxacin doses recommended for treatment of E coli infections in chickens were compared. Mutation frequencies and QRDR sequence changes in gyrA and parC were also determined. RESULTS: In 2 of 15 E coli strains, MPCs were low (0.016 and 0.062 microg/mL), MPC:MIC ratios were 2 and 4, and the GyrA and ParC proteins had no mutations. In 9 susceptible isolates with a GyrA point mutation, MPCs ranged from 2 to 16 microg/mL. For isolates with double mutations in GyrA and a single mutation in ParC, MPCs were > 32 microg/mL (several fold greater than the maximal plasma concentration of enrofloxacin in chickens); mutation frequencies were also much lower, compared with frequencies for single-mutation isolates. CONCLUSIONS AND CLINICAL RELEVANCE: For E coli infections of chickens, MPC appears to be useful for determining enrofloxacin-dosing strategies. The high MPC:MIC ratio may result in enrofloxacin-treatment failure in chickens infected with some wild-type gyrA E coli isolates despite the isolates' enrofloxacin susceptibility (MICs 0.125 to 1 microg/mL). For infections involving isolates with high MPCs, especially those containing mutations in gyrA and parC genes, treatment with combinations of antimicrobials should be adopted.  相似文献   

18.
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.  相似文献   

19.
Fifty-six Staphylococcus aureus isolates recovered between 1998 and 2003 from 31 rabbit farms with and without problems of chronic staphylococcosis, were screened for resistance to enrofloxacin, erythromycin, gentamicin, lincomycin, neomycin, penicillin and tetracyclines using the agar dilution test. For penicillin, a disk diffusion test was also performed. The detection of tetP(B), tet(K), tet(L), tet(M), tet(O), tet(T), tet(W), erm(A), erm(B), erm(C) and mec(A) genes was done via a PCR assay. Four isolates showed resistance to erythromycin and lincomycin. These isolates were positive for the erm(C) gene in the PCR. Eleven strains were resistant to tetracyclines and all harboured the tet(K) gene. In the agar dilution test, five isolates showed resistance to penicillin, whereas in the disk diffusion test 12 isolates showed resistance. None of these 12 resistant isolates carried the mec(A) gene. Only one strain showed resistance to gentamicin, and all strains were susceptible to enrofloxacin and neomycin. This study demonstrates that resistance to antimicrobial agents in S. aureus isolates originating from rabbits is relatively rare compared to resistance in S. aureus isolates originating from other animals and humans.  相似文献   

20.
The purpose of the present study was to determine the prevalence of antibiotic resistance, with special attention to vancomycin, in 104 strains of Enterococcus, which is the sentinel bacterium isolated from dog and cat faeces samples. The phenotypic characterization of the isolates classified them as E. faecium (58%), E. avium (41%) and E. faecalis (1%). Sensitivity testing used the diffusion method according to the recommendations of CASFM (Comité de l'Antibiogramme de la Société Française de Microbiogie), to oxacillin, amoxycillin, amoxycilin + clavulanic acid, ampicillin, piperacillin, cefoperazone, imipenem, enrofloxacin, ciprofloxacin, οfloxacin, nalidixic acid, tetracycline, lincomycin, erythromicin and vancomycin. Minimum inhibitory concentration (MIC) determination by E test revealed a MIC to vancomycin of between 0.5 μg/ml and 3 μg/ml. All the strains were resistant to nalidixic acid, erythromycin, cefoperazone and oxacillin. We detected resistance to amoxycillin + clavulanic acid in 1.9% of isolates, to amoxycillin in 4.8%, to piperacillin in 13.5%, and to ampicillin in 21.2% of strains. A high prevalence of antibiotic resistance to lincomycin, tetracycline, enrofloxacin, ciprofloxacin and ofloxacin was found in 98.1%, 95.2%, 76.9%, 73.1% and 64.4% of strains, respectively. Resistance to vancomycin was not found, which indicates that there is no transmission risk of vancomycin‐resistant enterococcal strains to man or transfer of their resistance genes to other bacteria belonging to the endogenous flora of humans.  相似文献   

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