不同动物来源肠球菌的分离·鉴定及耐药性研究

[目的]为动物肠球菌感染机制的研究提供理论依据。[方法]采用常规细菌分离方法从不同动物的肛拭样品中分离肠球菌,利用基于肠球菌保守tuf基因的PCR方法对其进行鉴定,同时采用KB纸片法对分离到的肠球菌进行药敏试验。[结果]共分离到177株细菌,经鉴定确定为肠球菌。药敏试验结果表明,鸡源肠球菌对青霉素的耐药率为80%,牛源肠球菌为46.4%;猪源肠球菌对环丙沙星的耐药率为27.3%,羊源肠球菌为2.8%;鸡源肠球菌对高浓度链霉素的耐药率为62.9%,而羊源未出现耐药菌株。[结论]来源于不同动物的正常菌群肠球菌对某些抗生素表现出不同程度的耐药性。     

海氏肠球菌(Enterococcus hirae)发酵特性及应用

对实验所得并鉴定为海氏肠球菌(Enterococcus hirae)的菌株I-2进行发酵特性的考察,结果显示I-2具有良好的发酵特性。实验还将I-2用于酸奶发酵,并对其产品品质进行测定,各项指标均达到国家标准,且在发酵及后熟20d后活菌数依然能够保持在109CFU/mL以上,说明其具有良好的乳品开发潜力及保健功能。     

Antimicrobial therapy for multidrug resistant pathogens

Multidrug resistant bacteria are tremendous causes of morbidity and mortality in human medicine, and emerging pathogens in equine medicine. A variety of organisms, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus spp. (VRE) and multidrug resistant Acinetobacter spp., Pseudomonas spp. and Enterobacteriaceae are of concern in equine medicine. Veterinary practitioners need to be aware of key diagnostic, clinical, therapeutic, epidemiological and infection control aspects to limit the impact of these organisms on the equine, and perhaps human, population.     

临床感染猪肠球菌菌株的分离与鉴定

对分离自河南洛阳、济源、许昌、南阳等地送检病猪内脏的42份革兰阳性球菌分离纯化,根据细菌形态学、培养特性和生长耐性试验结果,初步确定为肠球菌,采用V itek-32全自动细菌鉴定系统对其进行鉴定,共鉴定出了34株肠球菌.其中,粪肠球菌(Enterococcus faecalis)10株、屎肠球菌(E.faecium)2株、铅黄肠球菌(E.casselifla-vus)22株.另有8株未鉴定到种的水平.     

猪源肠球菌两种致病基因和表型的检测

摘要：目的：调查53株猪源肠球菌2种致病基因和2种表型的分布。方法：应用聚合酶链反应检测53株肠球菌的2种致病基因,用50mL/L兔血平板和30g/L明胶平板检测β溶血和明胶溶解表型。结果：粪肠球菌、屎肠球菌和鸟肠球菌2种致病基因的检出率分别为cylA 94.4%、96.9%、100%; gelE 100%、87.8%、50%;β溶血检出率分别为72.2%、42.4%、0;明胶溶解检出率分别为100%、0、0。结论：细胞溶解素激活基因(cylA)明胶酶基因(gelE)为猪源肠球菌的主要致病基因;粪肠球菌2种致病基因和2种表型的检出率高于屎肠球菌;来源于新鲜猪肉中的粪肠球菌存在较强的毒力,提示注意食品卫生安全;在新鲜猪肉中检测到2株鸟肠球菌,基因型和表型检测说明其存在较弱毒力。     

Use of avilamycin for growth promotion and avilamycin-resistance among Enterococcus faecium from broilers in a matched case-control study in France

We assessed the putative link between avilamycin-resistant Enterococcus faecium carriage and avilamycin consumption in broilers. As part of the French programme of monitoring for antimicrobial resistance, broilers sampled at slaughterhouse in 1999 and 2000 and carrying avilamycin-resistant E. faecium were matched by slaughterhouse, slaughter month and production type (free-range, standard, light) with control broilers carrying avilamycin-susceptible strains. History of antibiotics consumption (either for growth promotion or therapeutic purpose) in the broiler flocks sampled was collected from the monitoring programme and consumption of each antibiotic class was screened as a potential risk factor. Avilamycin was a risk factor for avilamycin-resistant E. faecium carriage: OR = 2.3.     

A cell wall preparation of Enterococcus faecalis strain EC-12 stimulates β-defensin expression in newly hatched broiler chicks

In our previous study, a cell wall preparation of Enterococcus faecalis strain EC‐12 (EC‐12) prevented the colonization of vancomycin‐resistant enterococci (VRE) in newly hatched broiler chicks. Relatively early prevention against VRE colonization by EC‐12 administration may be related to the enhanced innate immune system. In this study we examined the effect of EC‐12 on the kinetics of immunoglobulin A (IgA) concentration in the cecal digesta of chicks from 1 day to 14 days old to evaluate humoral immunity. We also examined the effect of EC‐12 on β‐defensin mRNA expression and lysozyme production. The IgA concentration in the cecal digesta showed a decline in chicks from 2 to 8 days old and then a recovery up to when they were 14 days old. The concentration tended to be higher in EC‐12‐administered chicks than in control chicks at 14 days old. EC‐12 administration did not stimulate the lysozyme activities in the alimentary tract. However, β‐defensin mRNA expression in the tongue and the bursa of Fabricius was higher in chicks administered EC‐12 than in the control chicks at 5 days old. These results indicate that β‐defensin may be one of the major defense mechanisms inhibiting VRE colonization in young chicks.     

新疆北疆地区猪源粪肠球菌的耐药性分析

为了解新疆北疆地区猪源粪肠球菌的耐药性及相关耐药基因型的分布情况,本试验采用K-B（Kirby-Baller）琼脂扩散法检测了49株猪源粪肠球菌对8种抗菌药物的敏感性,并采用PCR法对9种相关耐药基因进行检测并测序,测序结果与GenBank中的相应基因序列比对。药敏试验结果显示,分离菌对链霉素耐药率最高,其次为青霉素和红霉素,对呋喃妥因、氨苄西林高度敏感。PCR检测结果显示,β-内酰胺类耐药基因tem的检出率最高,为93.88%,其次是四环素类耐药基因tetM,为85.71%,喹诺酮类基因gyrA和parC检出率均为42.86%,氨基糖苷类耐药基因aph（3'）-Ⅲ、aac（6'）/aph2″和ant（6'）-Ⅰ的检出率分别为36.73%、16.33%和16.33%,未检出mefA和ermB基因。本试验从表型与基因型分析发现,北疆地区猪源粪肠球菌的多重耐药现象非常严重,且其耐药表型与基因型并不完全一致。     

猪源肠球菌中氟苯尼考耐药性调查及fexA基因环境研究

本研究旨在调查猪场中肠球菌对氟苯尼考的耐药性,检测氟苯尼考耐药基因,并测定肠球菌中氟苯尼考耐药基因fexA的基因环境,从而分析其可能的传播机理。以四川某猪场分离鉴定的50株肠球菌为研究材料,开展分离株对氟苯尼考的药物敏感性试验。运用PCR技术检测分离株中氟苯尼考耐药基因cfr、fexB、fexA、floR和estDL136。运用热不对称性PCR（TAIL-PCR）技术获得fexA基因周围序列信息,分析其基因环境。运用反向PCR技术验证序列中环化结构的存在,同时运用交叉PCR技术检测20株猪源肠球菌fexA基因的基因环境。结果显示,在分离出的50株肠球菌中,有34株对氟苯尼考耐药（MIC ≥ 16 mg/L）,耐药率为68%。PCR结果显示,20株含有fexA基因,28株含有fexB基因,14株同时含有这两种基因。TAIL-PCR和测序结果显示,分离株DKC5中fexA基因存在于12 945 bp的Tn554转座子中。Tn554转座子可形成环化结构,其中的重复序列可形成含有2 395 bp的环化结构。本试验结果表明,猪源肠球菌对氟苯尼考耐药率较高,主要由fexA和fexB基因介导,fexA基因存在于Tn554结构中。预测fexA基因是经两次插入整合后进入DKC5分离株基因组序列的,这为fexA基因的水平传播提供了遗传依据。