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1.
We attempted to isolate Listeria monocytogenes from skin, contents of large intestines and carcasses of cattle introduced to a slaughterhouse in order to identify source of contamination for this pathogen. Sixty skin samples, 60 samples of the contents of large intestines and 30 carcass samples were colleted in June, August and November 2003 for use in this study. Listeria spp. and L. monocytogenes were isolated from 30 (50%) and 3 (5%) of the cattle skin samples, respectively. However, no Listeria spp., including L. monocytogenes, were isolated from intestinal contents or carcasses. Seven isolates were obtained, of which five and two strains were serotypes 1/2a and 1/2b, respectively. Genetic analysis suggested that there was persistent inhabitation of the pathogen around the area investigated in this study.  相似文献   

2.
Domestic animals belonging to seven different species (cattle, sheep, dogs, cats, pigs, chicken and goats) were investigated as natural reservoirs for attaching and effacing Escherichia coli (AEEC). For this, 2165 E. coli strains from faeces of 803 animals were examined for the presence of the intimin -(eae) gene as a characteristic of AEEC strains. Ten percent of the animals were found to excrete AEEC, most frequently found in sheep (19.2%) and pigs (17.6), followed by cattle (10.4%), dogs (7.2%), cats (6.5%) and poultry (2.3%). The 97 AEEC strains from animals were grouped into 44 serotypes. Only four E. coli serotypes (O2:H8, O26:[H11], O109:[H25] and O145:[H28] were found in more than one animal host species. AEEC O26:[H11] strains were most frequently isolated (13.4%) being present in cattle, poultry, pigs and sheep. A search for virulence markers associated with enterohemorrhagic E. coli (EHEC) revealed Shiga-toxin genes in three (3.1%) AEEC strains from sheep. Bundle forming pili genes as a trait of typical enteropathogenic E. coli (EPEC) were detected in four (4.1%) strains from dogs and cats. The remaining 90 AEEC strains were classified as atypical EPEC. Typing of intimin genes revealed intimin beta being present in 51.5% of the strains, followed by intimins theta (23.7%), epsilon (6.2%), kappa (5.2%), zeta (5.2%), alpha, eta and iota (each 1.0%). Our data indicate that domestic animals and pets constitute an important natural reservoir of AEEC strains, and some of these (O26:[H11], O103:H2, O128:H2, O145:[H28] and O177:[H11]) are known to occur as pathogens in humans.  相似文献   

3.
为鉴定分离自新疆北疆绵羊单核细胞增生李斯特氏菌,本研究采用多重PCR方法,鉴定来自病发地区部分羊场的发病绵羊、健康绵羊、羊舍环境和乌鸦粪分离的30株李斯特氏菌分离株的8株单核细胞增生李斯特氏菌分离株血清型。结果为4株发病绵羊株有3株鉴定为单核细胞增生李斯特氏菌,血清型为1/2a或4b,1株为非单核细胞增生李斯特氏菌;5株健康绵羊株血清型为1/2a;其余来自羊舍水源的3株、乌鸦粪的2株及健康绵羊16株为非单核细胞增生李斯特氏菌,表明来自发病绵羊、健康绵羊及参考菌株LM血清型之间具有相关性。  相似文献   

4.
Listeria monocytogenes is a foodborne pathogen of major concern for public health in industrialized countries. Listeria carriage by pigs at the herd level could be a primary source for carcass contamination. Forty-seven finishing pig facilities were involved in the present study designed to compare three environmental swabbing sites in order to detect Listeria spp. in piggeries. Swabs were taken from the pen walls, the perianal regions of the pigs and the trough/feeder of the piggery premises. Listeria contamination of wet or dry feed given to the pigs was also investigated. The capacity of the various sampling sites for Listeria spp. detection were compared with a maximum likelihood estimation method. Listeria spp. were recovered in 74% of the pens studied and L. monocytogenes was detected in 15% of pens. With a specificity of 99%, sensitivity estimates (and 95% CI) of the Listeria spp. detection method were 93.4% (72.7-98.7) for pen walls, 73.1% (54.9-85.9) for pigs and 66.6% (48.6-80.7) for the trough/feeder. Listeria spp. were isolated from 84% of wet feed samples and 5% of dry feed samples. Listeria monocytogenes was found in 13% of wet feed samples. The type of feeding (wet versus dry) was associated (P < 0.001) with Listeria spp. contamination of both the pen and the feed. The results of this study confirm that Listeria spp., including L. monocytogenes, are present in pig facilities. Pen wall swabbing appears to be an effective way to assess Listeria spp. status of finishing pigs. The type of feeding (wet versus dry) could play a role in pig contamination.  相似文献   

5.
In six Swiss meat-processing plants 206 samples of cured and air-dried beef (Bündnerfleisch), salami and Mettwurst were analyzed for the presence of Listeria spp. Samples were taken during the fabrication, fermentation and drying of the products. Out of 44.7% of all samples Listeria spp. could be detected. 6.8% turned out to be L. monocytogenes, 37.4% L. innocua and 0.5% L. seeligeri. Listeria spp. were found in all production stages of the tested foods. The concentration of L. monocytogenes was always less than or equal to 20 MPN/g. 86% of the isolated strains formed part of the serogroup 1/2 and 14% of the serogroup 4. Listeria spp. could only be found on the surface of Bündnerfleisch. Both, L. monocytogenes and L. innocua were able to survive the maturation process of salami, even when the initial concentration was very low. The ripening was more often survived by L. innocua than by L. monocytogenes. It appeared that Mettwurst had the highest contamination rate of Listeria spp. (94.4%), followed by salami (46.7%) and Bündnerfleisch (23.1%). The corresponding proportions for L. monocytogenes were 8.0% (salami), 5.8% (Bündnerfleisch) and 0% (Mettwurst). Listeria spp. positive samples were found in every examined plant, L. monocytogenes in five of therm. The Listeria spp. contamination rates moved from 10.0% to 86.2%, those of L. monocytogenes from 0% to 12.1%.  相似文献   

6.
From 397 fecal specimens from apparently healthy and from diarrheic pigs, dogs, cats and cattle 59 strains (= 15%) of thermophilic Campylobacter (C.) spp. were isolated by culture. 39 strains were identified as C. coli and 18 as C. jejuni whereas 2 isolates could not be classified. None of the strains was found to be positive for cytotoxic enterotoxin in the GM1-ELISA. In the Vero-cell test 5 isolates showed a cytotoxic effect. The salt aggregation test (SAT) for indicating cell surface hydrophobicity was positive with 24 strains (5 C. jejuni, 19 C. coli). A correlation of isolation results with clinical manifestation could not be observed.  相似文献   

7.
Between 1991 and 1993, the intestinal contents and feces of wild animals in Japan were examined for the presence of Listeria. The wild animals examined included 623 mammals (11 species) and 996 birds (18 species). Listeria species were isolated from 38 (6.1%) of the 623 mammalian samples and 133 (13.4%) of 996 bird samples. The highest incidence of Listeria in the mammals was found in Japanese monkeys (20.0%) and that in birds was found in crows (43.2%). The incidence of Listeria in Japanese monkeys varied from 0 to 40.0% depending on the capture area. L. monocytogenes was isolated from II of these positive samples. Serovars 1/2a and 4b predominated in eight serotyped L. monocytogenes isolates.  相似文献   

8.
In order to compare the plate count method for quantitating Listeria, as published in the "Official Collection of Testing Methods" in section 35 LMBG (L. 00.00-22), to an MPN-method for Listeria based on the same mediums, these two detection methods for Listeria were tested in three sets of experiments and a routine sample status evaluation. A pure broth culture of L. monocytogenes, artificially with L. monocytogenes contaminated ground meat, artificially contaminated and cold stored ground meat as well as 77 ground beef samples from Berlin retail food stores were used in the four trials. The detection limit of the MPN-method is about 66% lower than the plate count method allowing detection of a clearly greater number of Listeria-positive samples from naturally contaminated ground meat. The MPN-method yielded more Listeria spp.-positive samples (rel. 43%) and more L. monocytogenes-positive samples (rel. 21%) versus the colony count method based on the results from the field trial using ground beef samples from retail food stores in Berlin. Nevertheless the standardized colony count method is preferred over the MPN-method for routine use because of its slightly higher productivity and much smaller variation in the results. However, the MPN-method is preferable for epidemiological studies because of the significance of the lower detection level. The random sampling evaluation of ground beef from retail stores indicated that 39% of the samples were Listeria spp.-positive and 31% were L. monocytogenes-positive when using the colony count method. A total of 56% of the meat samples were found to be Listeria spp.-positive and 38% L. monocytogenes-positive when the MPN-method was used. Population levels ranged from 10 to 580 cfu/g (Listeria spp.-positive samples) and from 10 to 270 cfu/g (L. monocytogenes-positive samples) for the colony count method. The MPN-method yielded population levels of 3.6 to 930 MPN/g for Listeria spp.-positive samples and 3.6 to 150 MPN/g for L. monocytogenes-positive samples. L. monocytogenes strains isolated using the colony count method belonged to the following serovars: 1/2a (46%), 1/2b (13%), 1/2c (33%), 3b (4%) and 4c (4%). A similar serovar isolation pattern was found for L. monocytogenes-positive MPN-tubes. The most common serotype was 1/2a (43%), followed by 1/2c (32%) and 1/2b (14%). The serotypes 3c, 4b and 4c were all isolated 4% of the time.  相似文献   

9.
Listeria abortions were established in foetuses of cattle in 1.2% of the cases investigated in the Erfurt region and 1.8% in the Cottbus region from 1984 to 1989. The isolated strains have been found biochemically to be L. monocytogenes. The serological discrimination revealed a majority of serovar O I, II. Typing by phages of a part of isolated strains showed a clear predominance of code number 000 124 by the 1/2 a isolate (corresponds to O I, II). This type of phages seems to have a epizootiological importance. Listeria abortions were found in (a lot of 63) flocks in the Erfurt region. Nevertheless there were almost no accumulations of listeria abortions and listeria encephalitis at the same time in the analysed flocks.  相似文献   

10.
In the Kanto area a total of 245 wild rats were captured. All rats captured in Ikebukuro (110 rats) and 9 out of 41 rats in Yokohama were Rattus rattus, and all other 126 rats were Rattus norvegicus. In Kashima and Ikebukuro, listeria was isolated from 28 rats (77.8%) and 27 rats (24.5%), respectively, but in the other 4 areas listeria was isolated from 0-7% rats. Listeria monocytogenes was isolated from 12 rats (10.9%) captured in Ikebukuro and 2 rats in Kashima and Numazu. The frequent isolation of L. monocytogenes in buildings suggests the possibility of R. rattus as a reservoir of L. monocytogenes and the continual environmental contamination in buildings by L. monocytogenes.  相似文献   

11.
Altogether 496 samples of meat, lymph nodes, process water and swabs from different places in the abattoir were examined for the presence of Listeria spp. L. monocytogenes was isolated from 31 (6%) and other Listeria spp. from 65 (13%) samples. L. monocytogenes was isolated from 2 of 10 beef meat samples, 4 of 50 pig meat samples and 1 of 21 lymph nodes of pigs. No Listeria bacteria were isolated from lymph nodes of cattle. The highest percentage of Listeria was recovered from the unclean sections (cattle 22% and pigs 27% ) and the highest frequency was observed during the winter months.  相似文献   

12.
Seasonal variation in the fecal shedding of Listeria spp. in dairy cattle was examined by collecting a total of 3,878 fecal samples during a period of two years. The prevalences of Listeria spp. and L. monocytogenes were higher during the indoor season (12.7% and 9.2%, respectively) than in samples collected from the animals on pasture (5.3% and 3.1%, respectively). The highest frequencies of Listeria spp. (19.4%) and L. monocytogenes (16.1%) were detected in December. Listeriae were isolated from at least one of the dairy cows from 45.8% of the 249 herds examined. 2.9% of the 314 milk samples collected from the farm bulk tanks on 80 dairy farms on four different occasions yielded L. monocytogenes. The seasonal occurrence of these bacteria in milk reflected the frequencies of Listeria in the fecal material but not those in the main roughage used; grass silage and pasture grass. Fecal material is considered to be a potential source of contamination of raw milk by L. monocytogenes. Investigation of the numbers of viable Listeria organisms in different animal fodders is considered essential in further epidemiological studies of these bacteria.  相似文献   

13.
Listeria ivanovii is a Gram-positive bacterial pathogen that is capable of causing abortions and stillbirths in farm animals, particularly sheep and cattle. In terms of morphological, biochemical and molecular characteristics, L. ivanovii resembles other Listeria species such as L. monocytogenes, a pathogen of both man and animals. In this study, through comparative analysis of genomic DNA from the six Listeria species, a L. ivanovii specific clone (liv22-228) containing a 946 bp insert was isolated. This clone contained the 5' ends of two divergently transcribed L. ivanovii genes and an intergenic spacer region, similar in organization to homologous regions from the L. innocua and L. monocytogenes genomes. Regions of low homology in the clone were identified by comparing to the L. innocua and L. monocytogenes genomes, and oligonucleotide primers (liv22-228F and liv22-228R) were designed. These primers amplified a 463 bp band from genomic DNA of L. ivanovii strains only, but not from other Listeria species or common bacteria. Thus, PCR employing L. ivanovii specific primers (liv22-228F and liv22-228R) provides a useful and straightforward method for rapid and precise determination of L. ivanovii.  相似文献   

14.
Brain samples of 849 wild ruminants (654 roe deer, 189 red deer and 6 chamois) from Bavaria were examined for the occurrence of encephalopathies caused by bacteria, using cultural, serological and genetic methods. In addition, 87 brain samples were investigated histologically for clarification of the pathogenetic relevance of specific microorganisms. Using conventional bacteriological methods, 464 different bacteria were isolated. 229 of them could be differentiated to the genus level and 235 to the species level. Totally, 35 different bacteria species were isolated, most frequently Micrococcus spp., Bacillus spp. and E. coli. Listeria spp. were detected in 43 brain samples (37 from roe deer, 5 from red deer and 1 from chamois). Sixteen strains were identified as L. innocua, 14 as L. monocytogenes, 9 as L. seeligeri and 4 as L. grayi. Serological investigations of L. monocytogenes showed that 9 strains belong to serotype 1/2a and five to 4b. Analysis of the geographical distribution of the Listeria findings indicate a statistically significant (p<0.011) regional aggregation in Unterfranken (prevalence for roe deer: 12.2%, versus 4.5% in Oberbayern-Schwaben, 6.1% in Niederbayern-Oberpfalz and 0% in Oberfranken-Mittelfranken). The histological investigation (HE staining) of 87 tissue samples contaminated with encephalitis relevant bacteria showed inflammation of different severity (mild meningitis and choroiditis (n = 26) to moderate (meningo)encephalitis (n = 13)) in 41 cases.  相似文献   

15.
由河南省南阳地区患“怪叫病”黄牛脑组织分离鉴定了5株狂犬病病毒,建立了检测狂犬病病毒抗原的夹心间接斑点酶联免疫吸附试验、检测狂犬病病毒抗体和中和抗体的夹心阻断酶联免疫吸附试验和微量免疫酶试验.应用所建立的方法,结合小鼠中和试验,对疫区牛、马、猪、羊、犬、猫、鸡、鼠和蝙蝠9种动物的1138份血清标本进行了检测,结果发现阳性率达12.65%,其中疫点内牛、猪、犬、猫和鼠的阳性率更高,为20%左右.根据动物群中较高阳性率,亦即隐性感染动物的存在,提出了南阳地区黄牛狂大病除因疯犬或带毒犬咬伤所致者外,可能还有因其他动物如鼠等咬伤甚至非咬伤感染途径的存在.在确定病性以及上述流行病学调查的基础上,实施了以管(制)、免(疫)、灭(扑杀)为中心的综合防制措施,经3年的工作,收到了明显的防制效果.  相似文献   

16.
Inhibition of isolation of Listeria monocytogenes by bacteriocin-like substance (BLS)-producing Listeria innocua after enrichment culture was investigated. When 26 L. monocytogenes strains were examined in combination with eight L. innocua strains using the spot on lawn method, 52/208 (25.0%) combinations showed the growth inhibition of L. monocytogenes. When two Listeria species were cultured simultaneously in selective enrichment broth, inhibition of isolation of L. monocytogenes was observed in 12/52 of the combinations at 24h (23.1%), in 24/52 at 48h (46.2%) and in 30/52 (57.7%) after 7 days of incubation. The randomly amplified polymorphic DNA profiles showed no interstrain similarities between either strains of the BLS-producing L. innocua or the BLS-sensitive L. monocytogenes strains. Therefore inhibition by BLS-producing L. innocua of isolation of L. monocytogenes after enrichment culture is unlikely to be dependent upon a particular genetic profile.  相似文献   

17.
During a 3-year period, 4 cases of bovine abortion attributable to Listeria ivanovii were diagnosed from 243 bovine fetuses submitted for diagnostic evaluation. Listeria monocytogenes was isolated only once from a bovine fetus during this same time period. Pathologic findings were similar to those seen in abortions attributable to L monocytogenes. Consistent management factors were not recognized and breed susceptibility was not apparent. Listeria ivanovii is most often associated with abortions from sheep and is rarely reported from cattle. On the basis of findings in this study, L ivanovii must be included as a potential cause of bovine abortions.  相似文献   

18.
In this study, the virulence heterogeneity of Listeria monocytogenes serotype 4b strains of different origins was analysed on different levels. On one hand, the survival of L. monocytogenes strains in synthetic gastric fluid was studied. On the other hand, the pathogenic potential of strains with different inlB expression levels was analysed in an A/J mouse model for gastrointestinal listeriosis. Differences in survival capacity in gastric fluid and in in vivo virulence potential were observed between the tested strains. No clear correlation between the origin and the obtained data could be made. However, these results confirm the existence of heterogeneity in virulence potential of L. monocytogenes serotype 4b strains.  相似文献   

19.
根据GeneBank上发表的单核细胞增多性李氏杆菌(Listeria monocytogenes,LM)的内化素B(internalin B,inlB)和肌动蛋白A(actin A,actA)基因设计特异性引物,对5株不同来源的健康绵羊单核细胞增多性李氏杆菌和一株临床分离的单核细胞增多性李氏杆菌的inlB及actA基因进行PCR扩增,克隆测序分析其序列,并对2株部分基因缺失的单增李氏杆菌进行小鼠攻毒试验。结果表明:5株健康绵羊分离株单增李氏杆菌与临床分离株有较高的同源性,并且发现2株部分基因缺失的单增李氏杆菌;小鼠攻毒试验表明缺失株毒力有降低,但是不明显。  相似文献   

20.
As in recent years laboratory diagnostics of listeria has become part of food microbiology, the frequency of occurrence of the bacteria Listeria monocytogenes has been followed in various kinds of foods for a year. A total of 51 strains of L. monocytogenes (7.2%) was isolated from 700 kinds of samples (raw milk, pasteurized milk, meat surface, poultry, cheeses, thermally not treated meat products, food--industry machinery). As can be seen in Tab. I, the highest number of strains was isolated from meat surfaces (13.5%), followed by meat--industry machinery (12.72%), poultry (10%) and cheeses (5%). The lower numbers of strains were found out in thermally not treated meat products (3.8%) and in raw milk (3.3%). Pasteurized milk did not contain any strains. Our findings in raw milk (3.3%) and in pasteurized milk (0) are in agreement with the data cited e. g. by authors from the USA (Lovett et al., 1987), who mention the value of 4.2% in raw milk and the zero value in pasteurized milk. The percentage of strains monitored in cheeses (5%) can be evaluated as low as the assortment of investigated cheeses was small (all strains were isolated from soft ripening cheeses). German authors (Tham et al., 1988) speak about the 2.5% percentage of L. monocytogenes strains; this is in keeping with our findings. The findings in thermally not treated meat products (3.8%) can be evaluated as low although the number of strains found in raw meat was high.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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