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1.
During 2000-2002 the National Veterinary Reference Laboratory for Salmonella (NRL-Salm) in Germany typed 11,911 isolates from animals, food, feed and the environment. All of them were tested for their susceptibility to 17 anti-microbial agents. Sixty-three per cent of all isolates were resistant and 40% were multiresistant (resistant against more than one anti-microbial). This general resistance level was strongly influenced by those specific serotypes which dominate the Salmonella epidemiology in Germany. Salmonella Typhimurium DT104 isolates from pig and cattle, and their resulting food products, were multiresistant in 98 and 94% of the cases respectively. During the period 2000-2003 an increasing quinolone resistance especially in Salmonella isolates from poultry and poultry meat (to 26%) and in S. Paratyphi B D-tartrate positive isolates (to 64%) could be observed. This increase was accompanied by a shift towards higher minimal inhibitory concentrations for ciprofloxacin.  相似文献   

2.
Rodents play a major role in the transmission and maintenance of Salmonella contamination cycles in poultry facilities. However, very limited field data are available regarding the transmission routes, infection cycle, and shedding patterns of Salmonella by naturally infected wild rodents from commercial layer farms. In this study, a total of 128 resident wild roof rats (Rattus ratus) were captured from a Salmonella-contaminated layer facility. All roof rats were divided into 51 laboratory cages, and weekly monitoring of Salmonella fecal shedding patterns was conducted for 53 wk. Seven roof rats from cages that were observed to frequently shed Salmonella were isolated in individual cages, and daily Salmonella monitoring was performed for 35 days. At the end of monitoring, each roof rat was euthanatized, and isolation of Salmonella from different organs was performed. Results of weekly monitoring of Salmonella showed that 21 of 51 cages (41.2%) were positive for Salmonella Infantis, while two cages (3.92%) were positive for Salmonella Enteritidis. Moreover, 11 cages were positive for Salmonella for at least two sampling weeks. Isolation of Salmonella from fecal droppings was mainly observed during the first 12 wk of captivity. The longest interval between two Salmonella-positive fecal dropping was 24 wk. In the daily Salmonella monitoring, only Salmonella Infantis was isolated from fecal droppings, in which the highest number of Salmonella Infantis organisms per fecal dropping was at 1 x 10(8) colony-forming units (cfu), while the lowest measured quantity was 1 x 10(3) cfu. It was noted that the frequency of Salmonella shedding in fecal droppings appeared to have a linear correlation (r = 0.85) with the number of Salmonella organisms (cfu) per fecal pellet (P < 0.05). Moreover, pulsed-field gel electrophoresis analysis of Salmonella Infantis isolates revealed a single identical pulsed-field pattern. Salmonella Enteritidis isolates from fecal droppings and internal organs also generated a single identical pulsed-field pattern. Interestingly, Salmonella Infantis was not isolated from any of the organs examined, while Salmonella Enteritidis was isolated from the spleen and liver of one roof rat. These results may indicate that wild roof rats could persistently carry Salmonella and contaminate commercial poultry facilities through intermittent fecal shedding. Moreover, Salmonella Enteritidis in wild roof rats appears to be more of a systemic infection, in which isolation is most likely to occur in internal organs, whereas Salmonella Infantis is more likely an enteric type of infection, in which isolation is most likely to occur in the intestinal contents. It is very plausible that layer chickens could become infected with Salmonella through ingestion of Salmonella-positive fecal droppings or feeds contaminated with these fecal droppings from infected resident roof rats. This is likely one of the major reasons why layer houses can be persistently infected by Salmonella even if the facilities are thoroughly cleaned and disinfected and if replacement stocks are obtained from Salmonella-free breeders and rearing units. It is therefore a noteworthy suggestion that rodent control programs inside poultry premises comprise an essential and effective tool in the management and control of Salmonella contamination in layer flocks.  相似文献   

3.
Salmonella in cattle herds may behave as epidemic or endemic infections. An intensive longitudinal sampling study across all management groups and ages on six dairy farms in the UK was used to examine patterns of Salmonella shedding, following the prior identification of either Salmonella Dublin (SD) (three farms) or Salmonella Typhimurium (ST) (three farms) on the premises in the context of clinical salmonellosis. Individual faeces, pooled faeces and environmental samples (total 5711 samples), taken approximately every six weeks for 15-24 weeks, were cultured for Salmonella. SD was detected at low frequency (on any visit, 0.5-18.3 per cent of samples positive) and most consistently in calves. By contrast, ST was isolated at higher frequency (on any visit, 6.8-75 per cent of samples positive), and in higher numbers, up to 10(7) cfu/g faeces. Significantly more samples from calves were positive for ST than were positive for SD (50.6 per cent v 3.1 per cent; P?相似文献   

4.
The goal of this study was to estimate the accuracy of the invA-gene-based polymerase chain reaction (PCR) and a culture technique based on pre-enrichment with buffered peptone water, three selective enrichment media (selenite, tetrathionate and Rappaport-Vassiliadis broths) and four selective, solid media (Xylose-Lysine-Tergitol-4, Salmonella/Shigella, Hekton-Enteric and MacConkey), for the detection of Salmonella organisms from caecal samples from slaughter pigs. For this purpose a latent-class (Bayesian) approach was used. Two hundred and three slaughtered pigs were used after grouping them into two groups of 96 and 107 animals. Sensitivity (Se) was estimated to be 56% (95% probability interval 40, 76) for culture and 91% (81, 97) for PCR. The specificity (Sp) of the PCR was 88% (80, 95) while the Sp of the culture had been considered 100% in the statistical analysis as all culture-positive samples were confirmed by serotyping. PCR Se was not affected by the Salmonella serotypes present in the samples analysed. Accordingly, a minimum of 25.5% of the pigs was estimated to harbour Salmonella organisms in their faeces. It was concluded that bacteriology on caecal samples alone was a poor diagnostic method, and that the PCR method could be considered a cost-effective alternative to culture in Salmonella monitoring programmes. However, given the moderate Sp of this molecular technique, PCR-positive samples should be further confirmed through bacteriology.  相似文献   

5.
The National Reference Centre for Genetically Modified Organisms (GMO) detection was established in 2002 within the Istituto Zooprofilattico Sperimentale Lazio e Toscana, with the aim of providing scientific and technical support to the National Health System and to the Ministry of Health within the scope of the regulation of GMO use in food and feed.The recently adopted EU legislation on GMOs (Regulation CE no. 1829/2003 and no. 1830/2003) introduced more rigorous procedures for the authorisation, labelling and analytical control of food and feed consisting, containing or derived from GMOs. The National Reference Centre, besides its institutional tasks as one of the laboratories of the Italian National Health System, collects and analyses data and results of the national official control of GMOs; carries out scientific research aimed at developing, improving, validating and harmonising detection and quantification methods, in cooperation with other scientific institutions, the Community Reference Laboratory and within the European Network of GMOs laboratories (ENGL); collaborates with the Ministry of Health in the definition of control programmes and promotes educational and training initiatives. Objectives defined for 2004–2006, activities in progress and goals already achieved are presented.  相似文献   

6.
Salmonella strains isolated from poultry and poultry products over the period 2005-2006 have been investigated in order to ascertain the presence of extended spectrum cephalosporins (ESC) resistance. Twelve (ESC)-resistant isolates (n=1 S. Enteritidis, n=1 S. Braenderup and n=10 S. Livingstone) were characterized as SHV-12-positive. The multi-drug resistant S. Livingstone SHV-12-producing isolates, untypeable by pulsed-field gel electrophoresis (PFGE), showed a clonal relationship by random amplified polymorphic DNA (RAPD) analysis. The SHV-12 beta-lactamase is reported for the first time in Salmonella enterica strains isolated from poultry in Italy. The results suggest poultry as a source of Salmonella carrying extended spectrum beta-lactamases (ESBLs) genes and highlights the need of monitoring animal productions to prevent spreading of (ESC)-resistant strains.  相似文献   

7.
There is a strong interest to reduce the expenditure for the detection of Salmonella spp. from animal faeces and environmental samples from primary production according to ISO 6579:2002 Annex D by including a rapid and effective method to detect Salmonella spp. already after pre-enrichment in BPW. It has been shown that real-time PCR methods are very effective to detect Salmonella organisms after pre-enrichment of foods. However, materials from primary animal production compose of much higher amounts of substances which might inhibit the sensitivity of real-time PCR. Different techniques of DNA isolation after pre-enrichment of artificially inoculated bovine faecal material were used to compare their detection limit and detection probability using an invA 5' nuclease real-time PCR approach. A detection probability of 100% was shown at 10(5) cfu/ml using the QIAamp DNA Stool Mini Kit (Qiagen, Germany), at 10(4) cfu/ml using the High Pure PCR Template Preparation Kit (Roche, Germany) and at 10(3) cfu/ml using thermal cell lysis or an in-house lab protocol, respectively. In comparison DNA isolation by thermal cell lysis revealed a very good detection limit, low costs and almost no risks of contamination. Furthermore, caecal contents from pigs were analysed by ISO 6579:2002 Annex D and the invA real-time PCR using thermal cell lysis for DNA extraction. As a result neither false positive nor false negative findings were obtained. Inclusion of the real-time PCR after pre-enrichment of samples in BPW followed by bacterial detection of Salmonella only with samples positive with real-time PCR might be a valuable tool to fulfil the international standard of ISO 6579:2002 Annex D but also to diminish the expenditures. However, it must be stated that the modification of an international standard method and its use in routine diagnostic requires the validation and registration of national and/or international competent authorities.  相似文献   

8.
The National Reference Centre for Genetically Modified Organisms (GMO) detection was established in 2002 within the Istituto Zooprofilattico Sperimentale Lazio e Toscana, with the aim of providing scientific and technical support to the National Health System and to the Ministry of Health within the scope of the regulation of GMO use in food and feed.The recently adopted EU legislation on GMOs (Regulation CE no. 1829/2003 and no. 1830/2003) introduced more rigorous procedures for the authorisation, labelling and analytical control of food and feed consisting, containing or derived from GMOs. The National Reference Centre, besides its institutional tasks as one of the laboratories of the Italian National Health System, collects and analyses data and results of the national official control of GMOs; carries out scientific research aimed at developing, improving, validating and harmonising detection and quantification methods, in cooperation with other scientific institutions, the Community Reference Laboratory and within the European Network of GMOs laboratories (ENGL); collaborates with the Ministry of Health in the definition of control programmes and promotes educational and training initiatives. Objectives defined for 2004-2006, activities in progress and goals already achieved are presented.  相似文献   

9.
环介导恒温扩增(LAMP)-检测沙门氏菌   总被引:1,自引:0,他引:1  
建立一种能够快速准确地检测沙门氏菌的LAMP方法。根据沙门氏菌invA基因设计了引物,然后进行LAMP反应条件的优化、特异性试验,通过LAMP与PCR灵敏度的试验与实际样品进行检出率的比较。LAMP方法特异性好,最佳反应温度为63℃,只对沙门氏菌进行扩增;沙门氏菌的检测灵敏度为7~8cfu/mL。LAMP方法检测沙门氏菌特异性强、灵敏度高、时间短且操作简便,有望成为快速检测沙门氏菌的新方法。  相似文献   

10.
建立一种能够快速准确地检测沙门氏菌的LAMP方法。根据沙门氏菌invA基因设计了引物,然后进行LAMP反应条件的优化、特异性试验,通过LAMP与PCR灵敏度的试验与实际样品进行检出率的比较。LAMP方法特异性好,最佳反应温度为63℃,只对沙门氏菌进行扩增;沙门氏菌的检测灵敏度为7~8cfu/mL。LAMP方法检测沙门氏菌特异性强、灵敏度高、时间短且操作简便,有望成为快速检测沙门氏菌的新方法。  相似文献   

11.
Coupling of immunomagnetic separation and polymerase chain reaction was used after preenrichment for the rapid detection of salmonellae in minced meat and chicken giblets. The primers used are specific to the origin of DNA replication (oriC) on the Salmonella chromosome and produce a 163 bp DNA fragment. The method allowed a screening of Salmonella free samples within 24 hours. It detected 5 serovars when inoculated in minced meat at a contamination level of 1 to 4 cfu/g. Compared with the method L 00.00-20 of the Official Collection of Methods of Analysis according to section 35 of the German Law on Food and Commodities it showed a sensitivity of 94% and a specificity of 87.5% for the examination of chicken giblets (n = 45) and a specificity of 100% for the examination of minced meat (n = 63).  相似文献   

12.
A polymerase chain reaction (PCR) assay was developed for the generic detection of Salmonella sp. and the identification of S. Enteritidis (SE), S. Gallinarum (SG), S. Pullorum (SP) and S. Typhimurium (ST) in material collected in the field from poultry. The specificity and sensitivity of the assay combined with Rappaport-Vassiliadis selective enrichment broth (PCR-RV) were determined, and field samples were analyzed to verify the validity of the method application. Specificity of the assay was tested using 29 SE, 11 SG, 10 ST and 10 SP strains, along with 75 strains of 28 other Salmonella serovars and 21 strains of other bacterial genera. The assay was 100% specific for Salmonella detection and ST identification. The primer pair for SE, SG and SP also detected S. Berta. PCR detection limits for Salmonella at the genus level were 2 ST, 8 SE, 1.1x10(3) SG and 1.8x10(5) SP cells. At the serovar level, detection limits were 7 ST, 1.2x10(3) SE, 4.4x10(7) SG and 1.8x10(6) SP cells. At the genus level, PCR-RV detected approximately 128% more positive field samples than the standard microbiological techniques and results were ready in 48h instead of 7 days. PCR-RV method is diagnostic of Salmonella at the genus level and ST at the serovar level, although other tests are needed to identify SE, SG and SP to serovar level.  相似文献   

13.
The objective of this study was to develop and analytically validate an ELISA for the measurement of alpha(1)-proteinase inhibitor (α(1)-PI) in serum and faeces from cats. Lower detection limit, linearity, accuracy, precision, reproducibility, and reference intervals were determined. The lower detection limits were 0.02 g/L for serum and 0.04 μg/g for faeces. The observed-to-expected (O/E) ratios for serial dilutions of serum and faecal samples ranged from 100.0 to 129.7% (mean±SD: 112.2±9.9%) and 103.5 to 141.6% (115.6±12.8%), respectively. The O/E ratios for samples spiked with seven known concentrations of α(1)-PI ranged from 82.3 to 107.8% (94.7±7.6%) for serum, and 78.5 to 148.7% (96.8±18.2%) for faeces. The coefficients of variation for intra-assay and inter-assay variability were <7.9% and <12.1% for serum, and 5.3%, 11.8%, 14.2%, and 7.7%, 10.2%, 20.4% for faeces, respectively. Reference intervals were 0.6-1.4 g/L for serum and upto 1.6 μg/g for faeces. We conclude that this ELISA is sufficiently linear, accurate, precise, and reproducible for clinical evaluation.  相似文献   

14.
多重荧光PCR检测水产品致病菌方法的建立与应用研究   总被引:1,自引:0,他引:1  
根据沙门氏菌invA基因、副溶血性弧菌toxR基因和大肠杆菌O157:H7 RFBE基因的保守序列,设计引物和探针,通过优化反应体系,测定其灵敏度和特异性,建立了可同时检测上述三种致病菌的多重实时荧光PCR方法。该方法对纯茵的检测灵敏度均低于1O cfu/PCR反应体系。人工染菌样品经6h增菌,检测的灵敏度可低于10c...  相似文献   

15.
The goal of this study was to improve the diagnostic applicability of genus- and serovar- (S. Enteritidis and S. Typhimurium) specific PCR systems in screening faecal and caecal samples of poultry, poultry feed and poultrymeat for Salmonella, by keeping the opportunity to obtain Salmonella cultures from positive samples. Peptone broth pre-enrichment cultures of the samples were tested by PCR. In faecal and caecal samples from broiler chicks a strong inhibitory action was frequently observed. This could be reduced markedly by the addition of bovine serum albumin (BSA) acting as amplification facilitator. The results of testing pre-enrichment cultures from artificially contaminated faecal, poultry feed and poultrymeat samples (using S. Enteritidis, S. Typhimurium and S. Hadar as contaminants) suggest that the sensitivity of the above systems is 10(1)-10(2) CFU g(-1) sample. The testing of 95 caecal samples from slaughtered chicks resulted in 49% culture-positive and 76% PCR-positive samples. The suitability of a generic real-time PCR for testing faecal samples of poultry was also studied. Its detection limit for these samples was found to be lower than that of the diagnostic PCR system. Both methods reduced the time required for Salmonella detection to 24-30 h, and the advantage of the real-time PCR was its increased sensitivity. We have established a diagnostic and a real-time PCR system for rapid and reliable genus- and serovar- (S. Enteritidis and S. Typhimurium) specific detection of Salmonella for monitoring purposes in the poultry food chain. Sensitivity is equal to, or higher than, that of the standard bacterial culture method, and the method still provides the Salmonella culture if needed.  相似文献   

16.

The National Reference Centre for Genetically Modified Organisms (GMO) detection was established in 2002 within the Istituto Zooprofilattico Sperimentale Lazio e Toscana, with the aim of providing scientific and technical support to the National Health System and to the Ministry of Health within the scope of the regulation of GMO use in food and feed.

The recently adopted EU legislation on GMOs (Regulation CE no. 1829/2003 and no. 1830/2003) introduced more rigorous procedures for the authorisation, labelling and analytical control of food and feed consisting, containing or derived from GMOs. The National Reference Centre, besides its institutional tasks as one of the laboratories of the Italian National Health System, collects and analyses data and results of the national official control of GMOs; carries out scientific research aimed at developing, improving, validating and harmonising detection and quantification methods, in cooperation with other scientific institutions, the Community Reference Laboratory and within the European Network of GMOs laboratories (ENGL); collaborates with the Ministry of Health in the definition of control programmes and promotes educational and training initiatives. Objectives defined for 2004–2006, activities in progress and goals already achieved are presented.

  相似文献   

17.
本研究针对沙门氏菌invA基因的保守序列,设计特异的LUX^TM荧光标记引物,通过优化反应奈件和参数,建立可快速检测沙门氏菌的LUX^TM荧光PCR检测方法。结果显示,该方法高度敏感,其对纯菌的检测低限达到10^2cfu/mL,经6h增菌培养后检测,对样品液的检测低限达到1cfu/mL;特异性强,测试的全部13株沙门氏菌标准和参考菌株均呈阳性反应,测试的全部27株非目标菌均呈阴性反应;重复性好,定量检测批内和批间的变异系数均小于2%。应用本方法检测食品样品240份,结果检出阳性4份,与TaqMan荧光PCR和SN标准检测结果完全一致。本方法可在8h内完成对样品中沙门氏菌的检测,其检测的快速性、敏感性和特异性与TaqMan荧光PCR技术相当,且检测成本较低。  相似文献   

18.
Salmonella and Campylobacter are common bacterial pathogens associated with human gastro-enteritis; and raw poultry is considered to be an important source of these bacteria. To evaluate whether the Salmonella serovars and Campylobacter spp. bacteria could be monitored for the purpose of microbial presence, enumeration and antimicrobial resistance in raw poultry, 152 poultry carcasses were randomly selected from 10 markets in retail outlets of Phnom Penh during March 2006 to February 2007. The majority of poultry samples was contaminated by Salmonella serovars (88.2%) and Campylobacter spp. (80.9%). A very high contamination of Salmonella was found at 3-4 log?? CFU/g for 22.4% of samples and of Campylobacter at 7-8 log?? CFU/g for 1.3% of samples. Fifty nine different Salmonella serovars contaminated 134 poultry carcasses; five most prevalent serovars covered 29.1% of serovars isolates (Anatum, Typhimurium, Corvallis, Stanley and Enteritidis). Three Campylobacter species contaminating 123 raw poultry were Campylobacter jejuni (50.0%), Campylobacter coli (29.0%) and Campylobacter lari (21.0%). High antibiotic resistance percentages were found among Salmonella serovars and Campylobacter spp. isolates. This study revealed that raw poultry at the retail outlets in Phnom Penh markets are contaminated with high prevalences of food-borne pathogens, and communicating the importance of minimizing this risk in reducing human infections.  相似文献   

19.
Diagnosis of paratuberculosis (Johne's disease) is stymied by the lack of 1 diagnostic tool that can be used to detect both subclinically and clinically infected animals. At present, fecal culture remains the single diagnostic test that can detect infection in both disease states provided the animals actively shed Mycobacterium paratuberculosis in their feces. Yet, fecal culture has a disadvantage associated with the protracted incubation period of 8-16 weeks before results are available. Detection of nucleic acids specific to M. paratuberculosis in fecal samples is a technique that can circumvent the culture method. This study describes a rapid, simple, and effective method to extract DNA from fecal samples and modification of a polymerase chain reaction assay for optimal sensitivity of detection. An evaluation of 1,000 well-characterized fecal samples was performed by the Colorado Department of Agriculture (Denver, CO) and the National Animal Disease Center (Ames, IA) to determine the sensitivity, specificity, and reproducibility of the new method. Results from this study show that the sensitivity of detection was highly dependent on the load of bacteria in the fecal sample with 81% detection of samples containing >70 colony-forming units (cfu)/g of feces and a 45% detection rate for samples containing less than 1 cfu/g. Similarly, reproducibility of the technique between the 2 laboratories (n = 250 samples) was much higher (75%) for the fecal samples containing high levels of M. paratuberculosis and reduced to 25% for samples with less than 1 cfu/g. An overall specificity of 83% was obtained for known negative samples. The method described here is rapid, simple, and inexpensive compared with other techniques. In addition, this method can detect animals that are shedding less than 1 cfu/g.  相似文献   

20.
Thirty five (35) rats (Rattus norvegicus) were trapped in the area of four egg producing poultry farms and were examined for Salmonella spp., micro-biologically. The samples were taken from liver, spleen and intestinal content. Cultures were made directly in MacConkey Agar, in Selenite broth and Rappaport Vassiliadis at 37 degrees C and 43 degrees C. Five strains of S. gallinarum and one strain of Salmonella subgroup II were isolated from the intestinal content of six rats. An experimental study was also carried out. Ten rats Rattus norvegicus were trapped near poultry farms of N. Greece. No Salmonella could be detected in their feces when examined three times by the Selenite 37 degrees C and Rappaport-Vassiliadis 37 degrees C methods. The rats were orally infected with an 18 hours culture of S. gallinarum (1 x 10(9)/ml microorganisms). One hundred and sixty samples of feces were periodically collected and examined for the isolation of the microorganism by the methods mentioned above. Although not any clinical sign of a disease was noticed, S. gallinarum was isolated from their feces up to 121 days post infection.  相似文献   

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