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1.
Although Salmonella remains one of the leading causes of foodborne illnesses in the United States, the Salmonella enterica serovars and genetic types associated with most infections appear to fluctuate over time. Recently, the Center for Disease Control and Prevention (CDC) has reported an increase in cases of salmonellosis caused by Salmonella 4,[5],12:i:-. Similarly, this unusual Salmonella serovar has been isolated from cattle and poultry in the state of Georgia. We examined the genetic relatedness of Salmonella 4,[5],12:i:-, isolated from several different poultry companies and dairy farms in Georgia, by pulsed-field gel electrophoresis (PFGE). Several Salmonella 4,[5],12:i:- isolates had PFGE patterns identical or similar to PFGE patterns of Salmonella Typhimurium isolated from numerous animal sources. We identified distinct PFGE patterns for Salmonella 4,[5],12:i:- and matching Salmonella Typhimurium PFGE patterns, identifying four "distinct" strains. We focused a more specific analysis on the poultry Salmonella 4,[5],12:i:- and Salmonella Typhimurium isolates and found that of these Salmonella 4,[5],12:i:- isolates, 32% lacked the entire phase 2 antigen gene, fljB; 61% contained partial deletion(s); and 4% had partial deletion(s) in fljB and an adjacent gene hin, 5' to fljB. Thirteen percent contained smaller deletions or point mutations not identified by our DNA probes. The Salmonella 4,[5],12:i:- isolates were positive for several genes present in the Salmonella Typhimurium, including lpfE (100%), sseI(96%), and spvC (93%). Genetic analysis indicates independent, spontaneous mutations in fljB in at least four distinct Salmonella Typhimurium strains of animal origin circulating in nature.  相似文献   

2.
Analysis of flagellin genes was carried out on strains of Salmonella Typhimurium, Salmonella Hadar, Salmonella Abortusequi, Salmonella Enteritidis and Salmonella Gallinarum serovars, using a PCR system designed in this study. The purpose of these studies was to explore the flagellin genes of biphasic and monophasic Salmonellae for future targeted genetic interventions. The PCR primers were designed for two different structural genes of flagellin (fliC, fljB), for the repressor of fliC (fljA), for the operator region of fliC, and for the invertase system responsible for phase variation in Salmonella (hin, hixL, hixR). PCR analysis revealed that all of the examined genes (fliC, fliC-operator, fljB, fljA, hin, hixL, hixR) were present in all S. Typhimurium (n = 10) and S. Hadar (n = 10) strains tested. The results obtained on S. Typhimurium and S. Hadar strains confirmed their biphasic character at DNA level. However, the S. Enteritidis (n = 46) and S. Gallinarum (n = 5) strains lacked the invertase system (hin, hixL, hixR) as well as the fljA and fljB genes, while fliC and its operator were detectable. Consequently, the S. Enteritidis strains could only express fliC gene resulting in phase H1 flagellin. The examined S. Gallinarum strains were also demonstrated to have a cryptic flagellin gene (fliC). On the other hand, PCR results on S. Abortusequi (n = 2) indicated that both flagellin genes (fliC, fljB) and the whole phase variation system were present in both strains tested but only the H2 phase gene (fljB) was expressed. The phenotype of these strains could be clarified by motility test and/or by classical flagellar serology. The findings are also substantiated by the results of serovar-specific PCR for S. Typhimurium and S. Enteritidis. In conclusion, the PCR system developed in this study proved to be suitable for characterisation of Salmonella flagellin genes and confirmed serological results regarding all S. Typhimurium, S. Hadar and S. Enteritidis strains. This system could also identify cryptic flagellar genes of S. Abortusequi and S. Gallinarum.  相似文献   

3.
Low cheetah (Acinonyx jubatus) birth rates were observed for a long time in a captive breeding facility in which Salmonella, which was possibly present in contaminated beef, was isolated from still-born lion (Panthera leo) cubs. Salmonella, including 14 isolates of Salmonella serovar typhimurium and 19 isolates of Salmonella serovar muenchen, was subsequently isolated 47 times from 378 meat samples at the facility during a 13-mo period. Salmonella, including 26 isolates of S. serovar typhimurium, 10 of S. serovar muenchen, and 11 other serovars, also was isolated 54 times from 119 fecal samples. Only three plasmid profiles were identified in 59 S. typhimurium isolates from both meat and fecal samples. Although random-amplified polymorphic DNA fingerprinting using different primers in the polymerase chain reaction was able to distinguish between S. typhimurium and S. muenchen and to demonstrate similar chromosomal DNA fingerprints in some of the isolates from meat and feces, the results were not consistent enough to prove that the Salmonella in the feces originated from contaminated meat. However, the predominance of only two serovars in the meat fed to carnivores and in the feces of these animals suggests that the meat was the source of the Salmonella organisms in the feces.  相似文献   

4.
The present report deals with Salmonella strains received at the German National Reference Laboratory for Salmonella (NRL-Salm) for routine diagnostic in the year 2009. Hence, the working group continues the previous report from Friedrich et al. (2010) about the documentation on the serovar distribution of Salmonella received at the NRL-Salm in the years 2004-2008. As in the recent years, most of the Salmonella strains originated from livestock and food. In the year 2009 the NRL-Salm received 4765 isolates, most of them (85,1 %) were routine diagnostic. Salmonella ser. Typhimurium, its monophasic variant S. enterica subspecies enterica serovar 1,4,[5],12:i:- and Salmonella ser. Enteritidis were the most prevalent serovars. The number of S. enterica subsp. enterica serovar 1,4,[5],12:i:- isolates increased in 2009, in comparison to the years 2004-2008, and became the second most prevalent serovar serotyped at the NRL-Salm.  相似文献   

5.
The mechanisms of Salmonella serovar-host specificity are not well defined. Pig ileal loops were used to compare phenotypic differences in early cellular invasion between non-host-adapted Salmonella serovar Typhimurium (SsT) and host-adapted Salmonella serovar Choleraesuis (SsC). By 10 minutes postinoculation, both serovars invaded a small number of M cells, enterocytes, and goblet cells. Multiple SsC organisms (up to 6 per cell) simultaneously invaded M cells, whereas SsT often invaded as one to two organisms per M cell. Internalization of both serovars resulted in vacuoles containing a single bacterium. The follicle-associated epithelium (FAE) of SsC-inoculated loops responded with more filopodia and lamellipodia although exhibiting less cell swelling than SsT. Additionally, SsT showed an enhanced affinity for sites of cell extrusion compared with SsC at 60 minutes. These results suggest: 1) both SsC and SsT exhibit non-cell-specific invasion as early as 10 minutes postinoculation, 2) Salmonella serovars exhibit differences in early invasion of FAE and M cells, and 3) cells undergoing extrusion may provide a site for preferential adherence by SsT and SsC.  相似文献   

6.
Passive laboratory-based surveillance data from Alberta Agriculture Food and Rural Development were analyzed for common Salmonella serovars, prevalences, trends, and for the presence of temporal clusters. There were 1767 isolates between October 1990 and December 2001 comprising 63 different serovars, including 961 isolates from chickens, 418 from cattle, 108 from pigs, 102 from turkeys, and 178 from all other species combined. Salmonella Typhimurium, Heidelberg, Hadar, Kentucky, and Thompson were the 5 most frequently isolated serovars. Approximately 60% of the S. Typhimurium were isolated from cattle, whereas over 90% of the S. Heidelberg, Hadar, Kentucky, and Thompson were isolated from chickens. Salmonella Enteritidis was rarely isolated. There was an increasing trend in isolates from chickens, cattle, and pigs, and a decreasing trend in isolates from turkeys. Temporal clusters were observed in 11 of 15 serovars examined in chickens (S. Anatum, Heidelberg, Infantis, Kentucky, Mbandaka, Montevideo, Nienstedten, Oranienburg, Thompson, Typhimurium, and Typhimurium var. Copenhagen), 5 of 5 serovars in cattle (S. Dublin, Montevideo, Muenster, Typhimurium, and Typhimurium var. Copenhagen), and 1 of 3 serovars in pigs (S. Typhimurium). Short-duration clusters may imply point source infections, whereas long-duration clusters may indicate an increase in the prevalence of the serovar, farm-to-farm transmission, or a wide-spread common source. A higher concentration of clusters in the winter months may reflect greater confinement, reduced ventilation, stressors, or increased exposure to wildlife vectors that are sharing housing during the winter. Detection of large clusters of Salmonella may have public health implications in addition to animal health concerns.  相似文献   

7.
Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has emerged during the last decade as a global health problem because of its involvement in diseases in animals and humans. Multidrug-resistant DT104 strains are mostly resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracyclines (ACSSuT resistance type). The genes coding for such resistances are clustered on the chromosome. This paper reviews new developments in the characterization of S. enterica Typhimurium DT104, its chromosomal antibiotic resistance genes and their spread among other S. enterica Typhimurium phage types and other S. enterica serovars, the development of specific detection methods, virulence characteristics, and the evolution of multidrug-resistance with regard to the emergence of quinolone resistance.  相似文献   

8.
The aim of this study was to determine the farm prevalence of Salmonella in 90 Alberta finishing swine farms over a 5-month period, to evaluate Salmonella distribution in the farm environment and to describe Salmonella serovar diversity on these farms. Ten veterinary practitioners selected 90 Alberta swine farms based on an annual production of > or =2000 market pigs per farm and the willingness of the producers to participate in the study. Between May and September 2000, twenty samples were collected from finishing swine and the environment of each farm. The annual production of selected farms represented approximately 25% of the market swine production in Alberta. Participating farms were geographically representative of major swine production areas in Alberta. Sixty (66.7%) farms had at least one Salmonella-positive sample, with confidence interval (CI) of 57.1-77.2%. Salmonella were detected in 14.3% of fecal and 20.1% of environmental samples. The number of Salmonella-positive samples per farm ranged from 1 to 19. Among environmental samples, Salmonella were most frequently recovered from boots (38.6%) and the main drain (31.8%). Twenty-two serovars were detected on the 60 Salmonella-positive farms. Serovars Typhimurium (78 isolates), Derby (71 isolates) and Infantis (47 isolates) were the most common. A single serovar was detected on 58 farms, while 2, 3 and >3 serovars were detected on 15, 10 and 7 farms, respectively. The Salmonella farm status changed frequently over the 5-month period indicating the dynamic nature of Salmonella infections on these farms.  相似文献   

9.
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10.
Salmonella Enteritidis is the predominant serovar associated with egg-borne salmonellosis in humans. The colonization of S. Enteritidis in the vagina may play a role in the production of S. Enteritidis-contaminated eggs. In the first experiment, the in vitro adhesion of S. Enteritidis in vaginal and follicular explants was compared with that of S. Typhimurium by bacteriological isolation methods. The mean number of S. Enteritidis associated with vaginal explants was significantly (P < 0.05) higher than S. Typhimurium associated with vaginal explants and both serovars associated with follicular explants. In the second experiment, the in vitro adhesion and invasion of S. Enteritidis strains in the vaginal epithelium was compared with that of several strains of S. Agona, S. Infantis, S. Hadar, S. Heidelberg, S. Montevideo and S. Typhimurium, by immunohistochemical methods. The mean number of Salmonella in the vaginal epithelium depended on their lipopolysaccharide (LPS) type, with the rank order as follows: LPS type O9 (S. Enteritidis) > LPS type O4 (S. Agona, S. Typhimurium and S. Heidelberg) > LPS type O7 (S. Montevideo and S. Infantis) and LPS type O8 (S. Hadar). This rank order of Salmonella invasiveness is in accordance with the frequency of Salmonella outbreaks involving contaminated eggs. These findings suggest that S. Enteritidis has a higher ability to colonize the vaginal epithelium than other serovars, and the Salmonella LPS type may play an essential role in tropism of the reproductive tract.  相似文献   

11.
The objective of this study was to describe the distribution of Salmonella spp. on Ontario grower-finisher pig farms. Eighty swine farms were visited from January through July 2004. On each farm, fecal samples were collected from 5 pens, 2 rectal samples and 1 pooled sample from fresh manure on the floor per pen. Salmonella was isolated from 91 (11%) of the 800 rectal samples and 73 (18%) of the 397 pooled samples. Overall, Salmonella was recovered from 37 (46%) of the 80 farms. On each positive farm, Salmonella was cultured from 1 to 7 pigs or 1 to 5 pens. Of the 37 farms, 18, 13, 5, and 1 yielded 1, 2, 3, and 4 serovars, respectively. The most common serovars were S. Typhimurium var. Copenhagen, S. Infantis, S. Typhimurium, S. Derby, S. Agona, S. Havana, and S. enterica subsp. I:Rough-O. The 3 most frequent phage types were PT 104, PT 104a, and PT 104b. There was a statistically fair agreement between samples collected directly from pigs and pooled pen samples in determining the Salmonella status at the pen and farm level (kappa = 0.6, P < 0.0001). However, in 62 pens, Salmonella status, serovars, or phage types differed between the pig and pooled pen samples. The distribution of Salmonella on the swine farms in this study indicates that, in developing an intervention strategy, priority should be given to farms positive for S. Typhimurium var. Copenhagen. Also, the variation in Salmonella status between pig and pooled pen samples deserves consideration in a sampling strategy.  相似文献   

12.
The red fox (Vulpes vulpes) can be considered as a relevant indicator species for Salmonella in the local environment and Salmonella faecal carriage was investigated in 215 red foxes in Norway shot during the winters 2002/2003 and 2003/2004. Fourteen (6.5%) of the foxes carried Salmonella. Four isolates were determined as serovars Kottbus (n=2) and Hessarek (n=2) of Salmonella enterica subspecies enterica, and one as S. enterica subspecies IIIb:61:k:1,5,(7). The remaining nine isolates were S. enterica subspecies enterica serovar Typhimurium 4,12:i:1,2 and all displayed the same pulsed-field gel electrophoresis (PFGE) profile designated A2. This serovar regularly causes disease outbreaks amongst small passerine birds during winter and most of these outbreaks are associated with the PFGE profile A2. The results strongly indicated that the Salmonella Typhimurium infections in red foxes were primarily acquired through ingestion of infected small passerines. To investigate the capability of the A2 strain to establish a true intestinal infection in the fox an inoculation experiment with an A2 isolate from small passerines was carried out in farmed silver foxes (V. vulpes). The experiment also included one strain with an uncommonly occurring profile (X201) from small passerines. To highlight possible differences in capability of the two inoculation strains to pass the acid gastric juice in the fox, in vitro studies of their acid tolerance was carried out. Also their catalase activity and biofilm production were studied. All three foxes inoculated with the A2 strain developed sub-clinical intestinal infection of 2 weeks duration, whereas none of the three foxes inoculated with the X201 strain shed this bacterium. The X201 strain displayed a much lower capability, than the A2 strain, to survive at pH 3 in vitro. The low acid tolerance probably made it difficult for the X201 strain to pass the stomach and establish an intestinal infection in the experimental foxes. Reduced catalase activity and biofilm production were found for the X201 strain, indicating that the low acid tolerance was caused by a defect in the stationary-phase stress response system.  相似文献   

13.
Fourteen and 22 each of Salmonella Enteritidis and Salmonella Typhimurium (S. Typhimurium) were isolated from animals from 1983 to 1999 in Korea and tested for their antibiotic resistance patterns, phage types and resistance gene patterns. S. Typhimurium isolates were highly resistant to streptomycin, sulfisoxazole and tetracycline, 95, 95 and 86%, respectively. The incidence of multiple antibiotic resistance (resistant to more than two drugs tested) of S. Typhimurium isolates was extremely high (100%) comparing to S. Enteritidis isolates (21%). Two of the five ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfisoxazole and tetracycline) resistant type S. Typhimurium isolates were phage type definitive type 104 (DT104).For the detection of resistance related genes in S. Enteritidis and S. Typhimurium isolates, particularly ACSSuT type S. Typhimurium, antibiotic resistance genes, cmlA/tetR, bla(PSE-1) and bla(TEM), and genus Salmonella specific gene, sipB/C, were amplified using four pairs of primers in a hot-start multiplex polymerase chain reaction (PCR). Two Korean isolates of S. Typhimurium DT104 showed bla(TEM) amplicons instead of bla(PSE-1) for the ampicillin resistance and they were susceptible to florfenicol. The multiplex PCR used in this study was useful in characterization of multiple drug resistant Salmonella isolates, especially ACSSuT type S. Typhimurium, and identification of beta-lactamase gene distribution among Salmonella isolates.  相似文献   

14.
As Salmonella enterica is an important pathogen of food animals, surveillance programmes for S. enterica serovars have existed for many years in the United States. Surveillance programmes serve many purposes, one of which is to evaluate alterations in the prevalence of serovars that may signal changes in the ecology of the target organism. The primary aim of this study was to evaluate changes in the proportion of S. enterica serovars isolated from swine over a near 20‐year observation period (1997–2015) using four longitudinal data sets from different food animal species. The secondary aim was to evaluate correlations between changes in S. enterica serovars frequently recovered from food animals and changes in S. enterica serovars associated with disease in humans. We found decreasing proportions of S. enterica serovar Typhimurium, serovar Derby and serovar Heidelberg and increasing proportions of S. enterica serovar 4,[5],12:i:‐, serovar Infantis and serovar Johannesburg in swine over time. We also found positive correlations for the yearly changes in S. enterica serovar 4,[5],12:i:‐, serovar Anatum and serovar Johannesburg between swine and human data; in S. enterica Worthington between avian and human data; and in S. enterica serovar 4,[5],12:i:‐ between bovine and human data. We found negative correlations for the yearly changes in S. enterica serovar 4,[5],12:i:‐ and serovar Johannesburg between avian and human data.  相似文献   

15.
A total of 29 breeding turkey holdings and 317 fattening turkey holdings were sampled between October 2006 and September 2007 in order to establish the baseline prevalence of Salmonella in turkeys in the UK. The weighted holding level Salmonella prevalence was found to be 20.1 per cent (95 per cent confidence interval [CI] 8.6 to 40.3 per cent) in breeding turkeys and 37.7 per cent (95 per cent CI 33.4 to 42.3 per cent) in fattening turkeys. For breeding turkeys, a weighted flock-level prevalence, as more than one flock per holding was sampled, was estimated at 7.1 per cent (95 per cent CI 3.2 to 14.8 per cent). A total of 13 different serovars were identified in the survey. The most frequent serovar in both turkey flock classes was Salmonella Kottbus, which was found on two breeding holdings and 63 of the fattening holdings giving weighted prevalences of 10.4 per cent (95 per cent CI 2.6 to 34.1 per cent) and 23.0 per cent (95 per cent CI 19.3 to 27.3 per cent), respectively. On breeding holdings, a single isolate of Salmonella Typhimurium, identified as DT12 (weighted prevalence 3.5 per cent [95 per cent CI 0.7 to 15.8 per cent] [holding], 0.7 per cent [95 per cent CI 0.1 to 3.7 per cent] [flock)], was found. On fattening holdings, there were 55 isolates of S Typhimurium from 16 holdings, giving a weighted prevalence of this serovar of 5.4 per cent (95 per cent CI 3.6 to 8.0 per cent). There were no isolates of Salmonella serovars Enteritidis, Hadar, Infantis or Virchow.  相似文献   

16.
为了解马流产沙门氏菌新疆分离株的分子特征及其鞭毛蛋白FliC基因的结构与功能,本试验运用PCR技术扩增了分离鉴定的2株马流产沙门氏菌新疆株FliC基因,克隆测序并对其进行了生物信息学分析。分析结果显示,成功获得了626 bp的FliC基因(GenBank登录号:KJ486797、KJ486798)。对分离的2株马流产沙门氏菌FliC基因的核苷酸序列同源性分析结果显示,FliC基因新疆分离株与GenBank登录的其他沙门氏菌分离株的核苷酸序列同源性为49.6%～100.0%。该结果表明马流产沙门氏菌的FliC基因在该菌进化和流行的过程中是保守的,本研究将为分析该病的分子流行和进一步利用FliC基因防制该菌引起的感染提供试验基础。  相似文献   

17.
Polymerase chain reaction (PCR) was used to amplify the spacer regions between the 16S and 23S genes of rRNA genetic loci of Salmonella serovars for their rapid identification. These genetic loci revealed a significant level of polymorphism in length across the species/serovar lines. When the 16S-23S spacer region amplification products were subjected to agarose electrophoresis, the patterns observed could be used to distinguish all the serovars of Salmonella tested. Unique elements obtained in amplification products were mostly clustered at serovar level, although certain genus-specific patterns were also observed. On the basis of the results obtained, the amplification of 16S-23S ribosomal spacer region could suitably be used in a PCR-based identification method for Salmonella serovars.  相似文献   

18.
沙门菌和志贺菌二重PCR检测方法的建立及应用   总被引：3，自引：2，他引：1  
根据GenBank提供的沙门菌invA基因序列和志贺菌ipaH基因序列设计引物,建立了二重PCR方法,在同一反应体系同时检测两种致病菌核酸,经二重PCR方法扩增后,在同一泳道同时检出沙门菌284 bp和志贺菌611 bp特异性扩增条带,而普通大肠埃希菌、金黄色葡萄球菌、变形杆菌、阪畸大肠埃希菌、绿脓杆菌、蜡样芽胞杆菌、马链球菌、产单核细胞李斯特菌、鹅大肠埃希菌、猪水肿病大肠埃希菌均未出现这两种条带.对PCR产物进行测序,测序结果与已发表的基因核苷酸序列比较,沙门菌同源性为93%～100%,志贺菌同源性为98%～100%.应用建立的沙门菌和志贺菌二重PCR方法对广西6个试验猴养殖场1 665份猴粪便样品进行检测,检出沙门菌阳性25份,志贺菌阳性90份,阳性检出率分别为1.5%和5.4%.表明建立的沙门菌和志贺菌二重PCR检测方法特异性强、敏感性高,适用于临床粪便样品的快速检测.  相似文献   

19.
The present study was carried out to report the occurrence Salmonella spp., Salmonella Enteritidis, and Salmonella Typhimurium in chicken abattoirs. Samples of feces; feathers; scald, evisceration, and chiller water; and rinse water of non-eviscerated, eviscerated, and chilled carcass were collected from six chicken abattoirs. Salmonella isolates were identified by a multiplex-PCR using three sets of primers targeting the invA, pefA, and sefA gene sequences from Salmonella spp., S. Typhimurium and S. Enteritidis, respectively. Salmonella spp. was detected in 10% (29/288) of the samples, whereas serovars Enteritidis and Typhimurium were identified in 62% (7/288), respectively. The results indicate the need to improve hygiene and sanitary standards in poultry slaughter lines, besides the education of food handlers and information to consumers.  相似文献   

20.
Chickens infected with Salmonella enterica serovars Typhimurium (ST) and Enteritidis (SE) still represent a major source of human food poisoning via consumption of contaminated meat and eggs. Vaccination represents a sustainable approach to control Salmonella in the chicken and the serovar specificity of immunity has the potential to impact on the need for multivalent vaccines. The issue of cross-reactive immune responses and cross-serovar protection was examined in these experiments. Cellular and humoral immune responses were measured by antigen-specific ELISA and splenocyte proliferation assays during primary infections (with ST and SE) and during a second challenge with homologous or heterologous serovars. Primary infection with ST or SE induced strong lymphocyte proliferation and high levels of specific antibody (IgM, IgG and IgA) responses with substantial serovar cross-reactivity. The occurrence of high levels of splenocyte proliferation and strong antibody responses corresponded to the initiation of clearance with both ST and SE. Re-challenge of ST and SE infection-primed chickens with either serovar resulted in significant levels of protection (assessed by bacterial numbers and rate of clearance) with little difference between homologous or heterologous challenge schedules. Relatively low levels of antigen-specific splenocyte proliferation were detected during secondary infection, which may be caused by splenic T cells exiting to the gut. In contrast, the more rapid specific antibody responses (compared with primary infection controls) indicate the development of a secondary antigen-specific adaptive response. The substantial level of cross-protection between serovars and the level of antigenic cross-reactivity indicates the potential for single serovar live vaccines to protect against both group B and D salmonellae.  相似文献   

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