噬菌体试验在细菌质控中的应用

噬菌体技术对沙门氏菌及志贺氏和腹泻大肠杆菌的检验具有初筛作,其特点快速简便和准确。在生产实际检验工作中具有很强的应用价值,尤其是用于志贺氏大肠杆菌和沙门氏菌引起的食物中毒事件具有针对性的检验作用。对患者的及时对症治疗,早期确诊康复都具有很大帮助。总之,利用噬菌体技术用来检验沙门氏菌及志贺氏和腹泻大肠杆菌,结果可信,在实际检验工作中具有推广应用的潜力。     

基于PCR技术的番鸭细小病毒和沙门氏菌混合感染诊断

2010年9月贵州省某养鸭场送检病鸭5例,为确诊病因,同时为其及时防治提供科学依据,对病例进行了流行病学调查、实验室剖检病变观察、细菌学、PCR检测。结果表明:该病例为番鸭细小病毒和沙门氏菌混合感染,分离的沙门氏菌具有高致病性,仅对氧氟沙星敏感,对多种常用药物产生耐药。     

北京市密云地区鸡白痢流行病学调查

2006年3月1日-2010年4月,北京市密云县疫控中心对不同日龄鸡,进行鸡白痢平板凝集试验,规模(商品)蛋鸡检测数5380只,其中阳性数1737只,阳性率占30.8%,散养蛋鸡检测数3205只,其中阳性数1574只,阳性率占49.1%。流行病学调查显示:规模场蛋鸡和散养蛋鸡,120～260日龄鸡白痢检出阳性率较高,产蛋高峰过后(360～400日龄)的鸡机体抵抗力下降,鸡白痢阳性率较低,此时进行检验可见有部分阳性鸡转为阴性的情况,密云县散养蛋鸡鸡白痢阳性率比规模场蛋鸡阳性率高。鸡白痢导致密云县商品蛋鸡淘率高的重要因素之一,给广大鸡场或散养鸡户造成了严重的经济损失。     

不同品牌市售鲜鸡蛋贮存过程中微生物变化比较研究

鸡蛋是人类膳食的重要组成部分,其产出与贮运销售过程中均存在沙门氏菌等致病菌污染隐患,直接影响鸡蛋的消费安全。作者对北京市场德青源、留民营等4种品牌包装鲜鸡蛋及散装鸡蛋在贮存过程中细菌总数、大肠菌群数及沙门氏菌数量变化进行了测定,研究了贮存过程中各品牌鸡蛋蛋壳、蛋清及蛋黄中的细菌总数,大肠菌群数随时间的变化情况及沙门氏菌的检出情况。研究结果发现,不同品牌的鸡蛋蛋壳表面在贮存初期细菌总数介于9.315×10²～1.367×10⁴ CFU/个,且随着贮存时间的延长呈上升趋势;品牌鸡蛋贮存初期蛋内容物均未检出污染细菌,而在贮存6 d后检出污染细菌,细菌总数与大肠菌群存在随着贮存时间的延长而增加的变化。除A品牌鸡蛋外,市售鲜蛋均存在沙门氏菌污染,蛋壳表面污染率为1.67%～8.3%,内容物中污染率为1.67%～5%。其中散装鸡蛋的细菌总数,大肠菌群数及沙门氏菌检出率均高于其它几种品牌的鸡蛋。     

牛奶中抗生素残留的检测分析

抗生素能破坏人体肠道内的细菌平衡甚至使人发生过敏反应导致发热或过敏性休克。牛奶中的抗生素残留日趋受到社会各界的广泛关注。本研究用ELISA法对牛奶样品进行筛选,然后用HPLC法进行定量检测,依据检测结果对牛奶中抗生素的残留现状、来源及危害性等方面进行了分析。     

Aerobic oral bacteria in healthy captive snakes

Cotton swab samples were taken from the ventral surface of the mouth and from the proximal esophagus from 23 captive nonpoisonous snakes. The samples were cultured and investigated for aerobic bacteria. Both the mouth and the esophagus) samples of 6 snakes were negative. When the bacterial isolates of the mouth and the esophagus of the whole snake population were compared, it was found that the flora isolated from both locations were similar. However, when the samples of individual snakes were compared it was found that the same isolates were seldom found in both the mouth and the esophagus. The most common bacteria found were Pseudomonas sp., Alcaligenes-like organisms, Gram-positive rods and Gram-positive cocci belonging to the family Micrococcaceae. Important pathogens were seldom isolated. Salmonella virchow could be found from 2 snakes. The presence of bacteriologically negative samples, great variations in the composition of the flora between individual snakes, and the occurrence of typical environmental bacteria in the oral cavity all suggest that snakes lack a specific autochtonous flora: and the bacteria isolated from the oral cavity may be occasional environmental bacteria. The source of pathogens may be the environment, too.     

畜产品中沙门氏菌污染的检测与控制

目前,在我国发生的各类细菌性食物中毒中,由沙门氏菌污染而引起的食物中毒屡居首位。肉、蛋、奶等畜产品中含有丰富的营养物质,极易污染上沙门氏菌。本文简要介绍了畜产品中沙门氏菌污染的危害,并探讨主要的检测方法及其有效控制。     

Cloning and Sequence Analysis of gyrB Gene of Fluoroquinolones-resistant Salmonella Isolated from Chickens

Nine strains resistant to five fluoroquinolones (Ciprofloxacin, Ofloxacin, Enrofloxacin, Danofloxacin,Sarafloxacin) were isolated from clinical samples and extracted the chromosomal DNA of these strains. Designed primers to amplify the Quinolone-resistance-determining region (QRDR) of gyrB gene, then the PCR products were cloned and the sequence was analyzed. In comparison with the standarded strain NCTC5776, no mutation was found in the QRDR of gyrB gene of all resistant strains. The result indicated that the QRDR of gyrB has little relationship with fluoroquinolone resistance to salmonella.     

内蒙古地区鸡群沙门氏菌的分离及鉴定

本项实验对内蒙古地区７个盟市１１个养鸡场的鸡群进行了禽沙门氏茵的分离和鉴定。结果表明从不同生长阶段的鸡群中共分离到８４株沙门氏菌，鸡群的平均检出率为２５。５％，最高达６１．２％。血清学鉴定结果表明所分离的沙门氏菌分别属于４个种，它们是都柏林沙门氏茵（１５株）、鸡白痢沙门氏茵（２８株）、汤卜逊沙门氏菌（１０株）和猪霍乱沙门氏菌（１株），其中以都柏林沙门氏茵和鸡白痢沙门氏苗分布最广。４个种的沙门氏菌对雏鸡均表现致病性，致死率为１２．５～８７．５％。     

硫酸粘杆菌素体外抑菌效果的研究

将硫酸粘杆菌素按照在畜禽实际用量(2~20mg/kg)选择3个浓度(5mg/kg、10mg/kg、20mg/kg)分别配制溶液,按照常规方法制备成药敏片,分别置于接有大肠杆菌、沙门氏菌的普通琼脂板上,同时用标准药敏片庆大霉素、新霉素、强力霉素、盐酸环丙沙星、氧氟沙星、头孢曲松作对照,观察它们对大肠杆菌、沙门氏菌的抑菌效果。结果表明:13个浓度的硫酸粘杆菌素对大肠杆菌和沙门氏菌均高度敏感,并随药物浓度的增加抑菌圈也相应增大。2硫酸粘杆菌素对大肠杆菌、沙门氏菌的抑菌效果显著优于庆大霉素、新霉素、强力霉素、盐酸环丙沙星、氧氟沙星、头孢曲松等抗生素(P0.05)。