Phenotypic and Genotypic Characterization of Salmonella enterica in Captive Wildlife and Exotic Animal Species in Ohio,USA

The purpose of this study was to investigate the occurrence, antimicrobial resistance patterns, phenotypic and genotypic relatedness of Salmonella enterica recovered from captive wildlife host species and in the environment in Ohio, USA. A total of 319 samples including faecal (n = 225), feed (n = 38) and environmental (n = 56) were collected from 32 different wild and exotic animal species in captivity and their environment in Ohio. Salmonellae were isolated using conventional culture methods and tested for antimicrobial susceptibility with the Kirby–Bauer disc diffusion method. Salmonella isolates were serotyped, and genotyping was performed using the pulsed‐field gel electrophoresis (PFGE). Salmonella was detected in 56 of 225 (24.9%) faecal samples; six of 56 (10.7%) environmental samples and six of 38 (15.8%) feed samples. Salmonella was more commonly isolated in faecal samples from giraffes (78.2%; 36/46), cranes (75%; 3/4) and raccoons (75%; 3/4). Salmonella enterica serotypes of known public health significance including S. Typhimurium (64.3%), S. Newport (32.1%) and S. Heidelberg (5.3%) were identified. While the majority of the Salmonella isolates were pan‐susceptible (88.2%; 60 of 68), multidrug‐resistant strains including penta‐resistant type, AmStTeKmGm (8.8%; six of 68) were detected. Genotypic diversity was found among S. Typhimurium isolates. The identification of clonally related Salmonella isolates from environment and faeces suggests that indirect transmission of Salmonella among hosts via environmental contamination is an important concern to workers, visitors and other wildlife. Results of this study show the diversity of Salmonella serovars and public health implications of human exposure from wildlife reservoirs.     

Natural Occurrence of Campylobacter Species,Salmonella Serovars,and Other Bacteria in Unabsorbed Yolks of Market-Age Commercial Broilers

In the developing avian embryo, the main energy source is the yolk. Toward the end of the incubation period, the remaining yolk sac is internalized into the abdominal cavity. At hatch, the remaining yolk comprises 20% of the chick's BW and provides the nutrients needed for maintenance. Posthatch, chicks rapidly initiate the transition from yolk dependence to the utilization of exogenous feed. However, at present, it is not known what types of bacteria are found to be associated with unabsorbed yolk sacs from market-age broilers. For Experiment 1, one hundred 6-wk-old defeathered broiler carcasses were obtained from a commercial processing facility during each of 3 visits. In the second experiment, one hundred 8-wk-old defeathered broiler carcasses were obtained from a different commercial processing plant on 4 separate occasions. For both experiments, each carcass was aseptically opened and inspected for the presence of an unabsorbed yolk sac. Three to 5 carcasses containing a free-floating yolk sac (within the abdominal cavity) and the yolk stalk (without a yolk sac) and 3 to 5 carcasses containing an attached yolk and yolk stalk from each repetition were randomly selected and analyzed for levels and types of total aerobic bacteria (APC), Enterobacteriaceae (ENT), and for the presence of Campylobacter spp. and Salmonella serovars. The APC ranged from log 3.3 to >log 6.0, and the ENT ranged from log 2.8 to >log 6.0. Staphylococcus spp. and Streptococcus spp. were the predominant organisms in APC, whereas Escherichia coli and Hafnia alvei were found to comprise the ENT. Campylobacter spp. was found in 29% of the yolk stalks, 32% of the attached yolk sacs, and 13% of the free-floating yolk sacs. All Campylobacter isolates were determined to be Campylobacter jejuni, except for 1 attached yolk and yolk stalk, which was Campylobacter coli. Salmonella serovars were found in 26% of the yolk stalks, 48% of the attached yolk sacs, and 23% of the free-floating yolk sacs, and the majority of Salmonella isolates were Salmonella Typhimurium. The significance of these bacterial reservoirs and carcass contamination during processing is yet to be determined.     

鸡白痢沙门菌和鸡伤寒沙门菌PCR-RFLP鉴别

根据鸡白痢沙门菌和鸡伤寒沙门菌flic基因可变区两端的保守序列设计1对引物,PCR扩增出约866 bp的产物,用HinplI对PCR产物进行酶切,经RFLP分析区分鸡白痢沙门菌和鸡伤寒沙门菌.利用该技术对1株鸡白痢沙门菌标准株及2株鸡伤寒沙门菌标准株进行分子鉴别,结果与预计的RFLP模式相符,证明该方法可行.在此基础上...     

Prevalence,Characterization and Antibiotic Resistance of Salmonella Isolates in Large Corvid Species of Europe and North America Between 2010 and 2013

It is well understood that Salmonella is carried by animals and in majority of cases as asymptomatic hosts. Surveillance efforts have focused on the role of agriculture and contamination points along the food chain as the main source of human infection; however, very little attention has been paid to the contribution of wildlife in the dissemination of Salmonella and what effect anthropogenic sources have on the circulation of antibiotic resistant Salmonella serovars in wildlife species. A purposive survey was taken of large corvids roosting yearly between November and March in Europe and North America. Two thousand and seven hundred and seventy‐eight corvid faecal specimens from 11 countries were submitted for Salmonella spp. culture testing. Presumptive positive isolates were further serotyped, susceptibility tested and analysed for antibiotic resistance genes. Overall, 1.40% (39/2778) (CI = 1.01, 1.90) of samples were positive for Salmonella spp. Salmonella Enteritidis was the most prevalent serovar followed by S. Infantis, S. Montevideo and S. Typhimurium. No significant difference (P > 0.05) was found in the proportion of Salmonella recovered in Europe versus North America. The most variability of serovars within a site was in Kansas, USA with five different serovars recovered. European sites were significantly more likely to yield Salmonella resistant to more than one antibiotic (OR 71.5, P < 0.001, CI = 3.77, 1358) than North American sites, where no resistance was found. Resistance to nalidixic acid, a quinolone, was recovered in nine isolates from four serovars in four different sites across Europe. Large corvids contribute to the transmission and dissemination of Salmonella and resistance genes between human and animal populations and across great distances. This information adds to the knowledge base of zoonotic pathogen prevalence and antibiotic resistance ecology in wild birds.     

Prevalence of Salmonella and multiple antimicrobial-resistant Salmonella in California dairies

A cross-sectional survey was conducted on 75 randomly selected dairies in one California county. Salmonella was isolated from 12 (16%) dairies; S newport was isolated from 6 (8%). Chloramphenicol-resistant S newport and S dublin were isolated from 8 (10.7%) dairies. Dairies with Salmonella had higher average calf mortality rates (P = 0.064; odds ratio [OR], 3.8). Dairies with S newport had a greater than expected occurrence of illnesses in adult cows compared with dairies with no S newport (P = 0.048; OR, 6.7) or with no Salmonella serotypes isolated (P = 0.047; OR, 6.9). Dairies with chloramphenicol-resistant Salmonella were more likely to have used chloramphenicol during the preceding 18-month period compared with dairies with chloramphenicol-susceptible Salmonella or no Salmonella (P = 0.023; OR, 9.5).     

Vaccination of calves against Salmonella dublin with aromatic-dependent Salmonella typhimurium

Ten Holstein calves were divided into 2 groups. Five calves served as nonvaccinated controls, and 5 calves were vaccinated IM at 2 and 3 weeks of age with 10(9) aromatic-dependent (aro-) Salmonella typhimurium strain SL1479 containing O antigens 1, 4, 12. Serious adverse reactions to vaccination were not observed in the calves. Mean maximum rectal temperature increase in the vaccinated calves was 1.5 C. One calf had diarrhea and depressed appetite for 1 day after vaccination. At 5 weeks of age, all calves were challenge exposed orally with 1.5 X 10(11) virulent S dublin strain SL1367 (O antigens 9,12). After challenge-exposure inoculum was given, 1 of 5 vaccinated calves died and 4 of the 5 nonvaccinated calves died (P less than 0.05). Thus, some cross serotype protection against S dublin was induced by parenteral vaccination of calves with aro- S typhimurium strain SL1479, although protection was not complete.     

"聚焦沙门氏菌"专栏三:沙门氏菌的水平传播

沙门氏菌菌群并不是猪场自然产生的,而是被携带入内的.通过了解沙门氏菌的来源,可以检讨猪场的生物安全状况,以判断是否能充分抵御该细菌的入侵(图1). 实际上,任何进入猪场的物品都有可能携带沙门氏菌进入场内,但那些接触过动物或其排泄物的、或频繁大量进入猪场的、或能够近距离接近猪群的或特别是供猪食用的东西,能够带来最大的风险.     

沙门氏菌的研究进展

作者就沙门氏菌的毒力岛、质粒、致病机制和流行病学方面的研究作了简明扼要的概述,对沙门氏菌的防治研究具有重要的参考价值。