禽巴氏杆菌链霉素依赖株选育的研究

本研究用亚硝酸作为禽多杀性巴氏杆菌诱变剂,在含有一定剂量的链霉素的选择培养基上,将一株毒力较强的野生型禽多杀性巴氏杆菌经过诱变选育出一株依赖链霉素的突变株。突变株的形态、染色、生长特性、生化反应等与原野生型菌株相同,突变株经扫描电子显微镜观察,亦显示有荚膜,菌体不呈链状,经动物测试,其遗传稳定性及安全性良好,具有中等程度的保护效力。     

内蒙古呼伦贝尔地区羊源多杀性巴氏杆菌荚膜血清群分子流行病学调查

近年来,羊多杀性巴氏杆菌病在内蒙古自治区呼伦贝尔市时有发生。为了解呼伦贝尔市羊源多杀性巴氏杆菌荚膜血清型流行状况,通过建立多杀性巴氏杆菌分子生物学诊断方法,以羊病变组织为研究对象,对呼伦贝尔市羊源多杀性巴氏杆菌,进行荚膜血清群分子流行病学调查,同时应用K-B纸片琼脂扩散法,对分离菌株进行药物敏感性试验,以找到针对本地区流行株的敏感药物。结果显示:从采集的35份病羊肺组织病料中,分离出12株B群、9株D群多杀性巴氏杆菌,未分离出其他血清群;分离菌株对青霉素、链霉素耐药率最高,对氯霉素、四环素、诺氟沙星、环丙沙星敏感。结果表明,呼伦贝尔市流行的羊源多杀性巴氏杆菌以B群、D群为主,且分离菌株对青霉素、链霉素产生了较高的耐药性,需指导和监管抗菌药物的合理使用。本研究查清了本地区流行的优势多杀性巴氏杆菌血清群,找到了针对性敏感药物,这为该市羊巴氏杆菌病防控提供了有效的技术支撑,也对多杀性巴氏杆菌病流行病学监测和基因多样性研究奠定了基础。     

上海市猪源多杀性巴氏杆菌分离鉴定及其耐药性分析

本研究旨在调查上海市猪源多杀性巴氏杆菌对临床常用抗菌药的耐药情况,为该病的药物预防与治疗提供科学依据。2014~2015年在上海市11个规模化养猪场采集疑似多杀性巴氏杆菌感染的病料共计116份,采用细菌分离培养及PCR方法,分离鉴定出20株多杀性巴氏杆菌。采用纸片法测定了分离菌株对20种临床常用抗菌药的敏感性,结果表明,所有菌株对阿莫西林克拉维酸、头孢曲松、恩诺沙星、氟苯尼考、阿奇霉素和多黏菌素B敏感,这6种药物可作为本地区控制本病的首选药物。然而,超过50%的菌株对青霉素(65.0%)、复方新诺明(65.0%)、氨苄西林(60.0%)、链霉素(60.0%)、四环素(60.0%)耐药。耐药谱分析显示,85.0%的菌株对4~7种抗菌药耐药。本研究结果表明上海市猪源多杀性巴氏杆菌对临床常用抗菌药物耐药较严重,应加强养殖场猪多杀性巴氏杆菌的耐药性监测与防控。     

禽源多杀性巴氏杆菌的分离及生物学鉴定

为了研究江苏及其周边地区近期引起禽霍乱的多杀性巴氏杆菌分子流行病学特点,对送检病例进行细菌分离,使用PCR方法鉴定多杀性巴氏杆菌分离菌株的荚膜血清型和多位点序列分型,并对其进行药敏试验。结果显示,从暴发禽霍乱病例中分离出的12株细菌,皆为荚膜血清型A型的多杀性巴氏杆菌,其序列型为ST-129。在此基础上进行的药敏试验结果显示,12株多杀性巴氏杆菌对丁胺卡那霉素、氟苯尼考和多粘菌素B均敏感;但对卡那霉素、链霉素和强力霉素等表现不同程度的耐药性。因此,引起江苏及其周边地区暴发禽霍乱的多杀性巴氏杆菌序列型为ST-129,给禽类免疫全价细菌灭活苗可能是较好的防控措施。     

6株山羊源多杀性巴氏杆菌血清型、耐药性及致病性分析

为了研究6株分离自四川省内江市2个养殖场患病山羊支气管的多杀性巴氏杆菌的主要生物学特性,试验采用特异性PCR方法鉴定多杀性巴氏杆菌血清型,采用纸片扩散法(Kirby-Bauer)评价了临床分离菌株对14种抗菌药物的敏感性,采用Reed-Muench法测定分离菌株对昆明小鼠的半数致死量(LD_(50)),分析其致病性。结果表明:在6株多杀性巴氏杆菌中,4株为A型,2株为B型。分离菌株对青霉素和林可霉素100%耐药,而对复方新诺明和氟苯尼考具有较高的敏感性。分离菌株对昆明小鼠的半数致死量均大于5×10~(8.0) cfu/0.5 mL,致病性较弱。说明本次分离的山羊源多杀性巴氏杆菌菌株为弱毒株,丰富了我国山羊源多杀性巴氏杆菌的生物学特征,为其感染的防控提供了有用的信息。     

猪源多杀性巴氏杆菌的分离鉴定及其荚膜血清型鉴定

从病死母猪肺脏中分离到一株革兰氏阴性小杆菌,用生理生化鉴定、药敏试验、致病性试验和PCR鉴定方法对分离菌株进行鉴定,并用多杀性巴氏杆菌荚膜分型引物对分离株的荚膜血清型进行鉴定。结果表明:本菌为猪多杀性巴氏杆菌,对多种抗生素高度敏感,对小白鼠有强致病性;PCR扩增16SrDNA基因获得1415bp片段,分离株的16SrDNA核苷酸序列与多杀性巴氏杆菌(AY078999)的同源性为99%,因此该分离菌株被鉴定为致病性巴氏杆菌,命名为YN20110122株;本菌分离株为荚膜A型血清型多杀性巴氏杆菌。     

qseC及luxS双基因缺失对多杀性巴氏杆菌毒力及其交叉免疫保护性的影响

qseC和luxS是多杀性巴氏杆菌群体感应系统相关基因,为探讨其双缺失对多杀性巴氏杆菌致病性及交叉免疫保护的影响,本研究在前期构建的牛源A型多杀性巴氏杆菌CQ2株(PmCQ2)qseC基因缺失株(ΔqseC)的基础上进行了luxS基因缺失,构建了qseC及luxS双基因缺失株(ΔqseCΔluxS)。与野生型PmCQ2相比,该双基因缺失株在生物膜产生方面显著上升,而其荚膜生成量、血清敏感性及其毒力却显著下调,与qseC单基因缺失相比,双基因缺失在调节菌株部分生物学特性方面具有正向或负向叠加效应。疫苗交叉免疫保护性方面,与ΔqseC及野生型PmCQ2比较发现,双基因缺失株中luxS基因的缺失,减弱了部分qseC基因缺失所赋予菌株的交叉免疫保护效果,但却增强了菌株对牛源F型多杀性巴氏杆菌的交叉免疫保护作用,相比PmCQ2的无交叉免疫保护作用,qseC及luxS双基因缺失仍赋予了菌株很好的交叉免疫保护性。研究结果表明,群体感应基因qseC和luxS均可调控多杀性巴氏杆菌毒力及其交叉免疫保护性,该双基因缺失株可作为多杀性巴氏杆菌广谱型疫苗候选菌株。     

禽霍乱弱毒菌苗的研究报告

我们在有关北京市鸡兔多杀性巴氏杆菌诱变弱毒菌株的研究(1984)基础上,进一步作禽霍乱弱毒菌苗的研究,目的在于测定化学药物NTG诱变并依赖     

多杀性巴氏杆菌的血清抗性及毒力比较研究

关于从禽霍乱得到的多杀性巴氏杆菌的毒力决定因素的研究进展甚微。很久以前就已知道了荚膜是导致禽霍乱的毒力因素 ,但其他因素 (象血清抵抗力在毒力方面似乎也很重要 )还没有得到足够的重视。一些巴氏杆菌菌株和其他革兰氏阴性菌 (如大肠杆菌和鲁氏耶尔森氏菌等 )已被证实其血清抵抗力与对动物的毒力有关。本研究对 87个巴氏杆菌野外分离株和 9个参考毒株在鸡、火鸡、鸭和猪血清中的生长情况进行了比较 ,并筛选出血清敏感株和血清抵抗株接种 18周龄蛋鸡。此研究的目的是比较多种多杀性巴氏杆菌菌株及相关种类对鸡、火鸡、鸭和猪血清的抵抗…     

新疆石河子规模化牛场多杀性巴氏杆菌的分离鉴定及药敏试验

为了确定石河子地区某规模化牛场出现呼吸困难、咳嗽、病牛消瘦甚至死亡的病因,本研究以病牛病变组织为研究对象,采用常规细菌分离鉴定和细菌16SrRNA序列分析来鉴定菌种,以及多杀性巴氏杆菌种特异性基因Kmt-1和各个荚膜血清型特异性基因(hyaD-hyaC、bcbD、dcbF、ecbJ、fcbD)PCR扩增来确定细菌的血清型,同时应用纸片扩散法对分离细菌进行药物敏感性试验和小鼠感染试验。结果表明,从病变的肺组织中分离到1株菌落为灰白色、露珠状、不溶血,染色为革兰阴性球杆状细菌,生化鉴定结果符合巴氏杆菌特征,同时16SrRNA序列分析与NCBI上已公布的多杀性巴氏杆菌16SrRNA序列同源性在99%以上;对多杀性巴氏杆菌特异性基因Kmt-1以及各血清型特异性基因PCR扩增只扩增到Kmt-1和hyaD-hyaC特异性基因片段;分离菌株对链霉素、庆大霉素、卡那霉素耐药,对其他30种药物敏感,同时感染小鼠全部死亡。结果显示从病牛体内分离到1株毒力较强的血清A型多杀性巴氏杆菌。     

应用聚合酶链反应检测禽多杀性巴氏杆菌的研究

根据基因库中禽巴氏杆菌病原的基因序列（U51470）,设计了一对跨幅为488bp的引物,并用这对引物对11个不同血清型的禽巴氏杆菌标准株、9株地方分离株和5株哺孔动物巴氏杆菌菌株及其它6种禽病病原进行了PCR扩增,结果11个血清型的禽源巴氏杆菌和9株禽巴氏杆菌地方分离株均得到了片段大小与实验设计相一致的PCR扩增产物,而对5个血清型的哺乳动物巴氏杆菌和其它6种禽病病原的扩增结果为阴性。该PCR能检出10pg的禽巴氏杆菌DNA模板。     

鹿源多杀巴氏杆菌荚膜分型的研究

采用Ｃａｒｔｅｒ苹膜群鉴定法将分离于我国鹿的３８株多杀巴氏杆菌鉴定为三个苹膜型,其中Ｂ型占６８．４％,Ａ型占１８．４％,Ｄ型占５．３％,３株未能确定型,占７．９,证实荚膜Ｂ型是我国鹿多杀巴氏杆菌流行的主要血清群。     

Multiple drug resistance in Pasteurella multocida and Pasteurella haemolytica from cattle and swine.

The results of antimicrobial susceptibility testing on 262 strains of Pasteurella multocida and 141 strains of Pasteurella haemolytica isolated from cattle and swine from 1971 to 1974 were analyzed for patterns of resistance to streptomycin, penicillin, tetracycline, and chloramphenicol, using a modified Kirby-Bauer procedure. Resistance was recorded for 80.5% of the isolants of P multocida and 92.2% of those of P haemolytica. Resistance to streptomycin was most frequent, followed by resistance to penicillin and tetracycline. Most cultures of P multocida and P haemolytica were susceptible to chloramphenicol. There were 9 patterns of resistance with the aforementioned antibiotics. The combinations, streptomycin and penicillin and streptomycin and tetracycline, each accounted for approximately 10% of the resistance patterns of P multocida. Approximately half of the 14 isolants of P haemolytica were resistant to the combination of streptomycin, penicillin, and tetracycline. These observations underscore the need for antimicrobial susceptibility testing of clinical isolants of P multocida and P haemolytica.     

Antimicrobial resistance in streptococcal species isolated from bovine mammary glands

Streptococcal species isolated from dairy cows with clinical mastitis were obtained from mastitis research workers in Florida, Louisiana, New York, Vermont, Washington, and West Virginia. Seventy-one streptococcal isolates were tested, including 39 strains of Streptococcus agalactiae, 21 strains of S dysgalactiae, and 11 strains of S uberis. The minimal inhibitory concentration of erythromycin, lincomycin, oxytetracycline, penicillin, spectinomycin, streptomycin, and tetracycline was determined for each isolate. Differences were not detected among strains with respect to geographic origin. None of the strains was resistant to penicillin. Lincomycin was the next most effective antimicrobial, with only 2 resistant strains of each streptococcal species. There were no differences among the streptococcal species with respect to resistance to either penicillin or lincomycin. Streptococcus uberis was more likely to be resistant to erythromycin than were S agalactiae and S dysgalactiae (P less than 0.02). Streptococcus agalactiae and S uberis had similar distributions for resistance to oxytetracycline, tetracycline, spectinomycin, and streptomycin. Strains of S dysgalactiae were more likely to have intermediate resistance to oxytetracycline and streptomycin than were strains of S agalactiae and S uberis, which were highly resistant to oxytetracycline and streptomycin (P less than 0.001). Differences were not detected among the streptococcal species with respect to resistance to spectinomycin. Resistance to multiple antimicrobials was observed in all streptococcal species tested. Although S dysgalactiae appeared to have a greater percentage of strains (73%) that were resistant to multiple antimicrobials than did S agalactiae (31%) or S uberis (45%), differences were not statistically significant.     

In vitro susceptibility of Escherichia coli of swine origin to carbadox and other antimicrobials

Swine fecal Escherichia coli isolates were tested with the Microtiter broth dilution method for susceptibility to carbadox and 11 other antimicrobials. Of the 138 strains, 136 were resistant to sulfadiazine, 120 to tetracycline, 95 to streptomycin, and 63 to carbadox. Resistance to the remaining antimicrobials also was noted in various degrees, with the exception of amikacin, to which all strains were susceptible. Carbadox-resistant strains also were resistant to other antimicrobials. The multiple resistance pattern was most common to sulfadiazine and tetracycline or a combination of sulfadiazine, tetracycline, and streptomycin.     

鸡多杀性巴氏杆菌的分离与鉴定

根据发病情况和病理变化,结合病原分离、动物试验、毒素试验、生化试验、药敏试验等,证实广西某鸡场鸡群急性死亡是由鸡多杀性巴氏杆菌引起的禽霍乱。     

Incidence of drug resistance and transmissible R factors in strains of E. coli isolated from faeces of healthy pigs

Two hundred and twenty-six strains of E. coli were isolated from faeces of 107 pigs at different ages and without clinical signs of infectious diseases. The resistance of the strains to sulphonamide, tetracycline, streptomycin, chloramphenicol, ampicillin, and nalidixic acid was determined. In 74 % of the animals the predominant E. coli flora was found to be resistant to one or more of the drugs mentioned. Fifty-three % of the strains were resistant. Multiple resistance was predominant among resistant strains (67 %). R factors transmissible to a sensitive strain of E. coli K12 W3132 were demonstrated in 28 %. The proportion of resistant strains was largest in young animals (0–14 weeks) accounting for 65 % of the strains isolated, as compared to 43 % of strains from pigs and sows (6 months or more). The incidence of resistance to sulphonamide, tetracycline, and streptomycin was high, whereas most of the strains were sensitive to ampicillin and chloramphenicol. All strains were sensitive to nalidixic acid.The incidence of resistance to antibiotics in a population of pigs to whom these drugs are not fed but applied as therapeutic agents solely seems rather high. When based on clinical findings only, the value is therefore questionable of sulphonamide, tetracycline and streptomycin treatment of infectious diseases caused by E. coli.     

Drug resistance in strains of Escherichia coli isolated from the intestinal tract of pigs in Norway.

Faecal samples from 95 healthy pigs and samples of jejunal content from 85 piglets suffering from colienterotoxaemia were tested for the presence of drug resistant E. coli strains. Practically all pigs in both groups harboured E. coli strains resistant to one or more of the 6 antibiotics/chemotherapeutic agents tested (Oxytetracycline, streptomycin, sulphaisodimidin, neomycin, ampicillin, chloramphenicol). Almost 100% of healthy and approx. 90% of diseased pigs harboured strains resistant to Oxytetracycline, streptomycin and sulphaisodimidin. Pigs with strains resistant to neomycin, ampicillin and chloramphenicol were less frequently found. The predominant coliform flora consisted of E. coli strains” resistant to Oxytetracycline, streptomycin and sulphaisodimidin in 71% to 81% of diseased pigs and in 47% to 69% of the healthy pigs. In diseased pigs ¾ of the animals had a coliform flora dominated by neomycinresistant E. coli strains.Of the 721 resistant E. coli strains isolated from healthy pigs, 11% were single resistant while the corresponding figure for the 518 resistant strains isolated from diseased pigs was 6%. Thus 89% and 94% of strains showed simultaneous resistance to 2 or more antibiotics. E. coli strains resistant to 3 or more drugs were found in approx. 60% and 70% of the isolates from healthy and diseased animals, respectively. Oxytetracycline/streptomycin/sulphaisodimidin resistance was most commonly found, approx. 22% and 38% of the strains from healthy and diseased pigs, respectively, showing this resistance pattern.Transmission of drug resistance which was examined in E. coli strains originating from the diseased pigs was demonstrated in approx. 76% of the isolates. The incidence of drug resistance transfer in single, double, triple and quadruple resistant strains was 11%, 68%, 97% and 98%, respectively.     

应用16S rRNA基因测序法鉴定禽多杀性巴氏杆菌的研究

应用 16SrRNA基因测序法对以疫苗标准强毒株C4 8_1和弱毒疫苗代表株G190E4 0为阳性对照株和分离鉴定的 2株禽源多杀性巴氏杆菌Chicken/guangxi/ 2 0 0 0_1、Chicken/guangdong / 2 0 0 2_1株 ,进行 16SrRNA基因序列分析。结果表明 ,2株分离菌与对照的强弱毒株之间的同源性为 10 0 %。后经Blastn分析Chicken/guangxi/ 2 0 0 0_1、Chicken/guangdong /2 0 0 2_1、C4 8_1、G190E4 0株与已发表 11株多杀性巴氏杆菌同源性高达 10 0 % ,与已发表的 34株多杀性巴氏杆菌同源性均超过 98% ,同时与其它巴氏杆菌种如溶血巴氏杆菌等同源性均低于 96 % ,进一步证实Chicken/guangxi/ 2 0 0 0_1、Chicken/guangdong / 2 0 0 2_1分离株均为多杀性巴氏杆菌。生化实验鉴定表明Chicken/guangxi/ 2 0 0 0_1、Chicken/guangdong / 2 0 0 2_1、C4 8_1、G190E4 0菌株均为subsp .Multocida亚种。     

Comparative bacterial drug resistance in modern battery and free-range poultry in a tropical environment

A correlation between the use of antibiotics and drug resistance was found among Escherichia coli strains isolated from modern battery poultry at the University of Ibadan, Nigeria. All 1248 E coli strains from university poultry and 2196 strains from a commercial poultry farm in Ibadan were resistant to tetracycline, streptomycin and sulphonamide, the minimal inhibitory concentrations of these drugs being found to be several times those of the control E coli NCTC 10418. In contrast, all 2284 strains isolated from free-range town and village poultry were sensitive to these drugs. In the tropical developing countries with poor environmental sanitation and low personal hygiene, this situation has public health implications.