新疆和静县羊源多杀性巴氏杆菌分离鉴定及耐药性分析

为了解新疆地区羊群中多杀性巴氏杆菌(Pasteurella multocida)的致病性及耐药性,2019—2021年采集和静县规模场及散养户中患呼吸道疾病羊咽拭子、病死羊肺脏等病理组织样品304份进行病原菌分离鉴定,采用人工感染试验和K-B药敏纸片法分别检测其致病性及耐药性。结果显示:共分离到124株多杀性巴氏杆菌,分离率为40.8%(124/304),其中87株(70.2%)具有致病性,可以引起小鼠死亡,对小鼠的致死率为40.0%~100%;87株致病性多杀性巴氏杆菌对阿莫西林、多西环素、链霉素等9种药物的耐药率为44.8%~100%,对其他药物的耐药率为2.3%~36.9%,全部表现为多重耐药,以耐9~11种药物为主。结果表明,新疆和静县羊群中致病性多杀性巴氏杆菌流行较为普遍,耐药较为严重,应根据药敏试验结果,选择敏感药物合理使用,同时结合环境消毒对其进行控制。     

猪繁殖与呼吸综合征病毒(PRRSV)协同感染细菌性疾病的分析研究

为了解湖北某养殖场猪繁殖与呼吸综合征病毒（porcine reproductive and respiratory syndrome virus,PRRSV）流行毒株的遗传变异和临床感染情况,试验采集10份疑似PRRS发病仔猪的肺脏、淋巴结等临床样品,应用RT-PCR方法扩增PRRSV的Nsp2部分基因用于定性检测分析,并对扩增的其中2份PRRSV阳性样品进行ORF5基因核苷酸序列测定,结合不同疫苗毒株开展同源性比对分析。为进一步揭示病因,通过多重PCR方法对10份发病猪的肺脏和12份鼻拭子样品进行了相关致病菌的鉴定,并对其中的2株不同病原菌开展药敏试验。结果显示,10份临床样品中有5份检测到美洲型变异PRRSV,病原阳性率为50%。ORF5全基因序列分析表明,2个流行毒株间的核苷酸同源性为99.7%,与以TJM-F92、JXA1-R、HuN4-F112等为代表的高致病性致弱疫苗毒株核苷酸同源性最高,为96.7%~97.0%;与美洲型标准毒株VR2332的同源性分别为87.6%和87.9%;与国内较早分离的经典毒株（CH-1R和R98株）的核苷酸同源性分别为92.9%和87.4%、87.7%。患病猪临床常见感染模式为PRRSV+PM+SS、PRRSV+PM或PRRSV+HPS,2株主要致病菌药敏试验表明,多杀性巴氏杆菌对头孢曲松、阿莫西林等药物高度敏感,猪链球菌对阿莫西林、氨苄西林、阿奇霉素等药物高度敏感。本研究揭示了该场保育猪的发病病原,并从分子水平明确了临床PRRSV与不同疫苗毒株的亲缘关系,为弱毒疫苗的合理选择使用和综合防控PRRS提供了实践依据。     

Effect of a variant infectious bursal disease virus (E/Del) on Salmonella typhimurium infection in commercial broiler chickens

The effect of infectious bursal disease virus (IBDV) on Salmonella typhimurium (ST) infections in broilers was investigated in terms of Salmonella shedding and persistence, pathogenicity, and isotype specific humoral immune responses. Thirty-six, 1-day-old, straight-run commercial broiler chickens that were Salmonella negative by polymerase chain reaction (PCR) and culture were divided into two groups of 18 chicks each (ST and ST-IBDV). One group (ST-IBDV) of chicks received the E/Del strain of IBDV (10(5.0) median tissue culture infective dose [TCID50]/ml) through the ocular and cloacal routes divided into doses of 50 microl each at 2 days of age. Both groups were then inoculated with 10(8) colony-forming units (CFU)/ml nalidixic acid-resistant ST in the drinking water at 3 days of age. Environmental Salmonella counts were higher in the ST-IBDV group at 2 and 3 wk postinfection (PI) compared to the ST group. ST carriage in the cecal contents between the ST and ST-IBDV groups was not statistically different. The ST-IBDV group had a single mortality at 10 days postinfection compared to none in the ST group. The ST-IBDV group had significantly lower bursa to body weight ratios at 4 and 6 wk, as well as higher bursal lesion scores than the ST group at 2, 4, and 6 wk PI. The ST group had significant increase in serum IgG from 2 to 6 wk PI in comparison to the ST-IBDV group, which had no significant changes over time. Both IgA and IgM were significantly increased at 4 and 6 wk relative to 2-wk levels. There was an IBDV-induced failure of anti-Salmonella IgG seroconversion over time in ST-IBDV. Both groups continued to shed high levels of Salmonella up to the end of the study despite high antibody levels in the ST group and an unimpaired IgM and IgA production in the ST-IBDV group, indicating a limited influence of humoral immunity on Salmonella clearance.     

Characterization of infectious bursal disease viruses isolated in 2007 from Delmarva commercial broiler chickens

A study was performed in 2007 to isolate and characterize infectious bursal disease viruses (IBDVs) in commercial broilers grown in the Delmarva (DMV) Peninsula region of the United States. Bursae of Fabricius were collected weekly from 1 to 4 wk of age from broilers on 10 farms with a history of poor performance. Microscopic pathology was used to determine the infectious bursal disease (IBD) status of the broilers. Bursae from 1- and 2-wk-old broilers did not show IBD microscopic lesions. Moreover, broilers on 1 of the 10 farms were IBD lesion free at 3 and 4 wk of age. However, 3 of 9 and 9 of 9 farms yielded broilers with IBD-affected bursae from 3- and 4-wk-old commercial broilers, respectively. Ten IBDV isolates were recovered from 3 of 3 lesion-positive bursal pools at 3 wk of age and 7 of 9 lesion-positive bursal pools at 4 wk of age. Analysis of the viral protein (VP) 2 genes identified all isolates as serotype 1 Delaware (Del) variant viruses. Five field isolates, each representing different molecular clades of the Delaware variant viruses, were selected for further study. Experimental infection of specific-pathogen-free white leghorn chickens with isolates DMV/4813/07, DMV/4947/07, DMV/4955/07, DMV/5038/07, and DMV/5041/07 produced gross and microscopic pathology of the bursa consistent with Delaware variant infection. Monoclonal antibody testing showed DMV/4813/07, DMV/4947/07, DMV/ 4955/07, and DMV/5041/07 to be similar to previous recognized variant viruses. However, DMV/5038/07 was found to be unreactive with the monoclonal antibodies that typically recognize reference strains STC, Del E, GLS, RS593, and AL2. In a challenge of immunity study, 10-day-old progeny from breeders immunized with a commercially available inactivated IBDV vaccine containing the Del E and classic strains were protected to a lesser degree against isolate DMV/5038/07 compared to Del E challenge based on microscopic lesion scores (P < 0.01) of the bursa. This result suggests the virus is antigenically different from the Del E strain contained in the vaccine. Collectively, the monoclonal antibody and progeny challenge of immunity findings suggest DMV/5038/07 is antigenically different from the Del E strain contained in the vaccine.     

1株鸭源巴氏杆菌强毒株的分离鉴定

对江西省某养鸭场送检的病死鸭进行病理剖检、细菌分离,经生化鉴定确定病原为多杀性巴氏杆菌。该分离菌株对头孢氨苄、头孢曲松、头孢唑啉、甲氧嘧啶、复方新诺明和氯霉素高度敏感;对大观霉素、卡那霉素等中度敏感;对头孢噻肟、四环素、林可霉素和诺氟沙星低度敏感;对阿莫西林、青霉素、氨苄西林和头孢吡肟不敏感。将分离菌株人工感染鸡、鸭、兔和小白鼠,感染后24 h内死亡率为100%,死亡动物均分离到与原分离菌株形态特征、培养特性一致的细菌,结果表明该分离菌株为多杀性巴氏杆菌强毒株。     

Susceptibility of Local Nigerian and Exotic Chickens to Infectious Bursal Disease by Contact Exposure

One hundred 6-week-old susceptible cockerels were inoculated with a pathogenic strain of infectious bursal disease virus (IBDV) and kept in the same pen as 100 each of 6-week-old pullets, local chickens and broilers. The cockerels developed depression and diarrhoea on day 3 post inoculation (PI) and most of the pullets and some of the local chickens and broilers showed similar signs on day 4 PI. Loss in weight was severe and similar in the pullets and local chickens, being significantly greater than that in the broilers from days 3–11 PI. The total mortality was 85%, 66.7%, 30% and 20% for the pullets, cockerels, local chickens and broilers, respectively. The lesions were more severe in the pullets and local chickens than in the broilers. IBDV antigen and antibody were detected, respectively, in all the bursal and serum samples from the infected chickens tested. The contact exposure method used in this study simulates better what happens in nature than inoculation with IBDV. The reduced mortality observed among the local chickens, compared with that (61.5%) seen in earlier studies using intraocular inoculation of IBDV, may have been due to behavioural differences that tend to result in their ingesting a relatively low dose of the virus.     

Safety and efficacy of two live Pasteurella multocida aro-A mutant vaccines in chickens

Two auxotrophic aro-A mutants of Pasteurella multocida designated PMP1 (serotype 1) and PMP3 (serotype 3) were tested as vaccine candidates to protect chickens against fowl cholera. A reliable intratracheal challenge method was established that resulted in > or = 75% mortality in both specific-pathogen-free chickens and commercial broiler breeders 24 hr after challenge. Dose protection studies indicated that at least 10(6) colony-forming units (CFU) of PMP1 and 10(8) CFU of PMP3 were required to provide complete protection against challenge in all birds. Although high doses of 10(9) CFU of the vaccine strains produced some endotoxinlike reactions, lower but protective dose levels produced no clinical sign or lesion in any chicken. Both vaccine strains provided cross-protection with a heterologous challenge strain PM206 (serotype 4). Future studies will examine the duration of protective immunity induced by the two vaccine candidates, PMP1 and PMP3, and cross-protection against other serovars.     

Sequential spread of Campylobacter infection in a multipen broiler house

Generally, colonization with Campylobacter jejuni is first detected in broilers 2-3 wk after hatching. Once introduced into a flock, this infection spreads very rapidly. The sources and routes of transmission of C. jejuni in broilers remain debatable. In this study, the spread of infection was monitored in a commercial multipen broiler house in which birds were contained in discrete groups and sampled sequentially. Colonization was monitored in two broiler flocks up to slaughter. Serotyping and fla typing methods were applied to differentiate all the C. jejuni strains isolated. In flock 1, colonization was first detected at 32 days of age in birds located at the rear of the house. By 40 days, nearly all the birds were infected with the same strain (fla type 1.9). However, at 46 days of age, a second strain (fla type 3.7) was detected in some of the birds. These birds were also located toward the rear of the house. In flock 2, infection was detected at 5 wk of age. This infection was once again first detected in birds located at the rear of the house. In this flock, only a single fla type (1.1) was isolated throughout. A survey of the broiler house relative to the location of first point of infection indicated the use of an entrance door unprotected by boot dips. However, securing this door during the second flock study did not prevent infection.     

山东省部分地区兔大肠杆菌病发病特点与药敏试验分析

于2011年1月至2012年7月,自山东省潍坊、临沂、淄博、滨州等部分地区送检114份病死兔病例中,经细菌分离鉴定,共分离到45株大肠杆菌。对上述大肠杆菌发病病例及发病日龄分析发现,1~3月龄发病数量占到64.4%;通过对其他病原的分离鉴定发现,不同病例存在球虫、魏氏梭菌、巴氏杆菌、波氏杆菌、链球菌、兔瘟等混合感染问题,混合感染病例占总病例近50%;对分离菌进行了药敏试验,发现其存在不同程度的耐药情况,其中对复方新诺明耐药性高达95.6%,对环丙沙星、阿莫西林、庆大霉素、新霉素的耐药性比率超过60%,而且二重耐药、多重耐药的情况较为普遍。     

Taxonomy of pasteurella anatipestifer. 1. DNA base composition and DNA-DNA hybridization analysis

DNA was isolated from 15 strains of Pasteurella anatipestifer and from one strain each of Moraxella nonliquefaciens, M. bovis, Pasteurella multocida, P. haemolytica, P. gallinarum, P. pneumotropica, and P. ureae. The guanine-plus-cytosine contents of P. anatipestifer ranged from 32 to 35 mole %, whereas those of Moraxella and Pasteurella spp. were much higher, ranging from 40 to 45 mole %. DNA-DNA hybridization analysis revealed that homology of nine P. anatipestifer strains to strains ATCC 11845 and PA 15 was 52 to 100%, whereas homology of Moraxella and Pasteurella strains to these strains was only 3 to 17%. Similarly, homology of P. anatipestifer strains, Moraxella, and Pasteurella species other than P. multocida to P. multocida reference strain P-2192 was low. These results strongly suggest that P. anatipestifer is genetically unrelated to either Pasteurella or Moraxella.     

Echocardiographic study of pulmonary hypertension syndrome in broiler chickens

Echocardiography was used to study cardiovascular structure and function during the development of pulmonary hypertension syndrome (PHS) in broiler chickens. Body weight-normalized right and left ventricular diameters at both end-diastole (RVDD, LVDD) and end-systole (RVDS, LVDS) were determined weekly in broilers reared under either normobaric (altitude, 96.7 m) or hypobaric conditions (simulated altitude, 2900 m) until 5 wk of age. Hypobaric-exposed broilers had larger RVDD at 3 and 4 wk of age and larger RVDS at 3, 4, and 5 wk of age. Hypobaric-exposed broilers also had larger LVDD at 2, 3, 4, and 5 wk of age and larger LVDS at 4 wk of age. Right (RVFS) and left ventricular fractional shortening (LVFS) were smaller in hypobaric- vs. normobaric-exposed broilers at 3, 4, and 5 wk of age and at 4 wk of age, respectively. Among hypobaric-exposed birds, PHS-positive (+) broilers had larger RVDD and RVDS than PHS-negative (-) broilers on week 3 and on weeks 1 and 3 after hypobaric exposure, respectively. PHS-positive (+) broilers also had smaller RVFS on week 1 after hypobaric exposure. Electrocardiographic and post-mortem data indicated that PHS+ broilers also developed right ventricular hypertrophy when compared with PHS-negative (-) broilers. These results are consistent with the hypothesis that PHS develops as a result of pulmonary hypertension and cardiac overload and suggest that PHS+ broilers have a greater and more persistent reaction to hypoxia than PHS- broilers.     

The pathogenesis of Pasteurella multocida serotype A:3,4 infection in turkeys: a comparison of two vaccine strains and a field isolate

The pathogenesis of avian pasteurellosis caused by two vaccine strains, M-9 and Clemson University (CU), and a highly virulent field isolate, 86-1913, of Pasteurella multocida (serotype A:3,4) was studied in 7-week-old turkeys inoculated by an oculo-nasal-oral technique. Turkeys inoculated with strain CU and isolate 86-1913 developed severe progressive bacteremia that began at 4 hours postinoculation (PI) and peaked at 16-20 hours PI. Turkeys inoculated with strain CU and isolate 86-1913 had significantly higher concentrations of bacteria in blood and tissues, and greater histologic lesion scores for necrosis, heterophil infiltrates, and intralesional bacteria than turkeys inoculated with strain M-9. Immunohistochemical staining specific for P. multocida demonstrated numerous extracellular bacteria in tissues from turkeys inoculated with strain CU and isolate 86-1913. The mortality for turkeys inoculated with isolate 86-1913 was significantly higher than for turkeys receiving the two vaccine strains.     

长毛兔巴氏杆菌病诊断与防控

2013年5月从山东某大型长毛兔场患有以鼻炎和化脓性肺炎为主要临床特征的病免中分离到1株细菌,经细菌培养、染色镜检、生化试验、PCR鉴定、动物试验证实分离菌株为荚膜血清A型巴氏杆菌;药敏试验结果表明,分离菌株对替米考星、恩诺沙星、氟苯尼考、头孢噻呋钠、阿莫西林等药物敏感;通过设计3个试验组:巴氏杆菌本场疫苗免疫试验组、恩诺沙星防治试验组、巴氏杆菌本场疫苗免疫与恩诺沙星联用试验组,每组500只长毛兔,连续观察30 d,结果发现巴氏杆菌本场疫苗免疫与恩诺沙星联用试验组对该病的防控取得了较为理想的防治效果.     

Chicken infectious anemia virus infection in Israeli commercial flocks: virus amplification, clinical signs, performance, and antibody status

The impact of chicken infectious anemia virus (CIAV) infection on commercial chicken flocks in Israel was examined by analyzing flocks with or without typical CIAV signs, signs of other diseases, or apparently healthy flocks. In 23 flocks (broilers and layers) of ages up to 8 wk, typical signs of CIAV infection (stunting, gangrenous dermatitis, and secondary bacterial infections) were recorded. When permitted by flock owners, in several cases among these 23 flocks the morbidity, mortality, and performance parameters were recorded; the presence of CIAV was detected by polymerase chain reaction (PCR); and the antibody status of parents and broilers was measured. In addition, total mortality, number of birds sold, total kilograms of meat sold, density (kg/m2), mean age at slaughter, daily growth rate in grams, total kilogram of food consumed, food conversion rate, and the European Index were calculated. We also surveyed flocks affected by other diseases, such as tumors, respiratory diseases, or coccidiosis, and flocks with no apparent clinical signs. The latter flocks were negative by CIAV-PCR, indicating that typical CIAV clinical signs are associated with one-step PCR-CIAV amplification. However, a small amount of CIAV might still be present in these flocks, acting to induce the subclinical effects of CIAV infection. These data indicate a link between the presence of virus sequences and typical CIAV signs and strengthen the concept that CIAV infection has a negative economic impact on the chicken industry.     

Protection of ducklings with a broth-grown Pasteurella anatipestifer bacterin

Pasteurella anatipestifer (PA) serotypes 1, 2, and 5 grew to high densities in tryptic soy broth and tryptose broth (TB) when the media were continuously shaken or aerated. Growth in 100 ml to 15 liters of TB exceeded an absorbance of 1.0 at a wavelength of 525 nm (about 0.7 for a 1/3 dilution) and contained more than 10(10) colony-forming units per ml. A bacterin was prepared from the three serotypes of PA grown in aerated TB. Two subcutaneous injections of this bacterin protected 70% to 85% of ducklings against experimental challenge with each of the three PA serotypes, which killed 90% to 100% of unimmunized controls. The bacterin could be diluted 1/5 without decreasing protection below 80%. Field studies on Long Island duck farms in 1980 and 1981 demonstrated significant reductions in mortality with the use of the broth-grown PA bacterin.     

Treatment of experimentally induced Pasteurella multocida infections in broilers and turkeys: comparative studies of different oral treatment regimens

Experimental fowl cholera was induced in 60 healthy 10-week-old broiler chickens and 8-week-old turkeys by intramuscular inoculation with approximately 80 colony-forming units (cfu) of Pasteurella multocida X-73 strain and with approximately 70 cfu of P. multocida P-1059 strain, respectively. This method of infection proved to be useful for evaluating the efficacy of anti-microbial medication, by measuring mortality, weight gain, pathological responses and frequency of re-isolation of P. multocida. The efficacies of two different dosing methods, continuous and pulse dosing, were compared. Using the continuous-dosing method, norfloxacin was administered to drinking water at 100 mg/l for 5 days in chickens. Efficacies were slightly improved compared with pulse dosing at 15 mg/kg bodyweight for the same length of time. The opposite was observed in turkeys, to the degree of control of mortality and maintenance of weight gain.     

竹鼠多杀性巴氏杆菌的分离鉴定及药敏试验

从红河州某竹鼠养殖场采集患病竹鼠病灶进行细菌分离培养,并对分离的菌株进行生化鉴定、动物回归试验及药敏试验。结果显示,分离的病原体为多杀性巴氏杆菌,该菌株对青霉素、诺氟沙星、阿米卡星等敏感,对链霉素、红霉素、庆大霉素、氯霉素等耐药。