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1.
E. P. Morato L. Leomil L. Beutin G. Krause R. A. Moura A. F. Pestana de Castro 《Zoonoses and public health》2009,56(5):229-237
Feces of 70 diarrhoeic and 230 non‐diarrhoeic domestic cats from São Paulo, Brazil were investigated for enteropathogenic (EPEC), enterohaemorrhagic (EHEC) and enterotoxigenic (ETEC) Escherichia coli types. While ETEC and EHEC strains were not found, 15 EPEC strains were isolated from 14 cats, of which 13 were non‐diarrhoeic, and one diarrhoeic. None of 15 EPEC strains carried the bfpA gene or the EPEC adherence factor plasmid, indicating atypical EPEC types. The EPEC strains were heterogeneous with regard to intimin types, such as eae‐θ (three strains), eae‐κ (n = 3), eae‐α1 (n = 2), eae‐ι (n = 2), one eae‐α2, eae‐β1 and eae‐η each, and two were not typeable. The majority of the EPEC isolates adhered to HEp‐2 cells in a localized adherence‐like pattern and were positive for fluorescence actin staining. The EPEC strains belonged to 12 different serotypes, including O111:H25 and O125:H6, which are known to be pathogens in humans. Multi locus sequence typing revealed a close genetic similarity between the O111:H25 and O125:H6 strains from cats, dogs and humans. Our results show that domestic cats are colonized by EPEC, including serotypes previously described as human pathogens. As these EPEC strains are also isolated from humans, a cycle of mutual infection by EPEC between cats and its households cannot be ruled out, though the transmission dynamics among the reservoirs are not yet understood clearly. 相似文献
2.
Samples of faeces from 57 dogs with acute diarrhoea, 82 dogs with chronic diarrhoea, 34 clinically healthy household dogs and 88 kennelled control dogs were analysed by hybridisation, using DNA probes to detect enteropathogenic Escherichia coli (EPEC) and enterotoxigenic E coli (ETEC), verocytotoxin-producing E coli (VTEC), enterohaemorrhagic E coli (EHEC), enteroinvasive E coli (EIEC) and enteroaggregative E coli (EAggEC). Samples of duodenal juice from 60 of the 82 dogs with chronic diarrhoea were also examined. Significantly more of the dogs with diarrhoea were excreting EPEC (acute 35.1 per cent, chronic 31.7 per cent) and VTEC (acute 24.6 per cent, chronic 28 per cent) than the kennelled dogs (EPEC 17.1 per cent, VTEC 0 per cent) or the household control dogs (EPEC 6 per cent, VTEC 5.9 per cent). Enteropathic E coli was also detected in the duodenal juice of 23 of 60 (38.3 per cent) of the dogs with chronic diarrhoea. The EPEC attaching and effacing A (eaeA) gene and the verocytotoxin 1 (VR1) gene coding for VTEC were often found together. There was good agreement between in vitro studies and hybridisation for the detection of eaeA and VT1. Isolates from the dogs with diarrhoea adhered significantly more to Hep-2 cells, and VT1-positive strains from the dogs with diarrhoea consistently killed more than 50 per cent of Vero cells. 相似文献
3.
These experiments determined the ability of Escherichia coli O157:H7 to colonize and persist in pigs simultaneously inoculated with other pathogenic E. coli strains. Three-months-old pigs were inoculated with a mixture of five E. coli strains. The mixture included two Shiga toxigenic E. coli (STEC) O157:H7 strains, two enterotoxigenic E. coli (ETEC) strains and one enteropathogenic E. coli (EPEC) strain. A high dose mixture with all five strains at 10(10)CFU/animal (CFU: colony forming units) and a low dose mixture with the STEC strains at 10(7)CFU and the EPEC and ETEC strains remaining at 10(10)CFU were used. The STEC strains persisted in the alimentary tracts of some pigs at 2 months post-inoculation, following inoculation with both the high and low dose mixtures. When all strains were given at 10(10)CFU (high dose) the STEC strains persisted in greater numbers and in more pigs than did the other E. coli strains. The results demonstrated that persistent colonization (> or =2 months) by E. coli O157:H7 can occur in pigs. These findings were similar to those reported from sheep inoculated with the same mixture of E. coli strains. The results are consistent with reports suggesting that pigs have the potential to be reservoir hosts for STEC O157:H7. 相似文献
4.
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
5.
This study was designed to investigate the antibiotic resistance, colicinogeny, serotyping and atypical biochemical characteristics of 41 Shiga toxin-producing Escherichia coli (STEC) strains detected using polymerase chain reaction from 90 E. coli strains isolated from 46 diarrhoeic calves. The STEC strains belonged to 14 different serogroups. Seventeen per cent of the STEC strains carried the eaeA gene while 14.28% of the 49 non-STEC strains were eaeA positive. Twenty eight (68.29%) of the 41 STEC strains were rhamnose non-fermentors. All the STEC strains revealed resistance to at least three of the antibiotics tested. 100% resistance was found against kanamycin and cephalexin followed by cephaloridine, enrofloxacin, amikacin, ampicillin, tetracycline, ceftiofur, ciprofloxacin, colistin and co-trimoxazole. Eighteen (44%) of the STEC strains produced colicin and all these colicinogenic strains were resistant to three or more antibiotics. Eleven STEC strains (26.82%) showed urease activity. The results of this study suggest that diarrhoeic calves are an important reservoir of STEC strains that are potentially pathogenic for farm animals and humans. Moreover, rhamnose fermentation, colicinogeny and atypical biochemical behaviour, such as urease activity, may serve as important markers or diagnostic tools for epidemiological surveys to trace the source of infection in disease outbreaks. 相似文献
6.
试验对新疆克拉玛地区106头健康成年荷斯坦奶牛的新鲜粪便进行了致病性大肠杆菌的分离鉴定、分型及遗传进化分析,初步掌握了调查地区奶牛致病性大肠杆菌的流行情况。参考USDA检测法,对106份粪便样品选择性增菌,分别利用麦康凯和伊红美蓝琼脂培养基对大肠杆菌进行分离纯化鉴别,通过PCR方法鉴定,获得55株大肠杆菌分离株,对这些分离株进行致病性大肠杆菌血清型鉴定、系统进化群及多位点序列分型（multilocus sequence typing,MLST）分析,利用goeBURST和Mega 7.0生物学软件进行聚类和进化研究,并进行流行病学分析。结果显示,106头健康荷斯坦奶牛的新鲜粪便中大肠杆菌的检出率为51.89%,55株大肠杆菌分离株共鉴定出9种与致病性相关的血清型,检出率为54.55%,其中肠致病性大肠杆菌（EPEC）、肠侵袭性大肠杆菌（EIEC）和肠产毒性大肠杆菌（ETEC）血清型检出率分别为21.82%、18.81%和14.55%,优势血清型为O142∶K86（B）和O124∶K72（均为10.91%）,前者属于肠致病性大肠杆菌,后者属于肠侵袭性大肠杆菌,而肠出血性大肠杆菌（EHEC）血清型检出率为0;系统发育群结果表明,55株大肠杆菌中B1群所占比例最高,为70.91%,其次为A群,占21.82%,D群所占比例较少,占7.27%,B2群未检测出;MLST分析可知,分离株中存在24个ST型,其中优势ST型为ST154（18.18%）;进化树分析显示有7个进化分支。结果表明,新疆克拉玛依地区健康成年奶牛粪便大肠杆菌多样性丰富,不仅存在多种致病性大肠杆菌,而且大肠杆菌菌株之间还存在一定的进化关系。因此,健康成年奶牛粪便也具有潜在的安全风险,应加强对奶牛粪便致病性大肠杆菌的检测和监控。 相似文献
7.
8.
Bandyopadhyay S Lodh C Sarkar M Ghosh MK Bera AK Bhattacharyya D Mondal DK Baruah KK 《Tropical animal health and production》2012,44(5):1063-1072
Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing
Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic
enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid,
nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from
RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates
in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study
indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public
health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant
for repeated occurrence of diarrhea in yaks. 相似文献
9.
Enteric infections caused by non-enterotoxigenic Escherichia coli in animals: occurrence and pathogenicity mechanisms. A review 总被引：9，自引：0，他引：9
L Okerman 《Veterinary microbiology》1987,14(1):33-46
Not all E. coli that cause diarrhoea in farm animals act by elaborating the classical heat-labile or heat-stable enterotoxins. These newly recognised animal enteropathogenic E. coli (EPEC) attach to and efface the microvilli of the gut epithelium and resemble the well known human EPEC. In rabbits, only this type of E. coli enteritis is known to be important and a similar disease has been shown to occur in cattle also. There is no doubt that adherence factors are important in the pathogenesis of animal EPEC, but they are not well understood when compared with the adhesion of human EPEC, or to the adhesion of animal ETEC. The enteropathogenic effect is probably due to Shiga-like toxin, a cytotoxin that is active on Vero cells and has also been called Verotoxin. A different type of Verotoxin is produced by most serotypes that are associated with post-weaning diarrhoea and oedema disease in pigs. This toxin is suspected to play a role in the pathogenesis of the latter. 相似文献
10.
Cortés C De la Fuente R Blanco J Blanco M Blanco JE Dhabi G Mora A Justel P Contreras A Sánchez A Corrales JC Orden JA 《Veterinary microbiology》2005,110(1-2):67-76
Faecal samples from 222 healthy dairy goats on 12 farms in Spain, as well as bulk tank milk samples of these farms, were screened for the presence of verotoxin-producing Escherichia coli (VTEC) and enteropathogenic E. coli (EPEC). VTEC and EPEC were isolated in 47.7 and 7.7% of the animals, respectively. VTEC were isolated more frequently from adults and replacement animals than from goat kids. In contrast, EPEC were detected more frequently from goat kids than from replacement animals and adults. VTEC or EPEC strains were not detected in the bulk tank milk samples. Although a selective enrichment protocol was used, the serotype O157:H7 was not detected. The most frequent serotypes among the 106 VTEC strains isolated from goats were O5:H-, O76:H19, O126:H8, O146:H21, ONT:H- and ONT:H21. None VTEC strain was eae-positive. The absence of the eae gene in the VTEC strains could indicate that these strains are less virulent for humans that the classical eae-positive enterohaemorrhagic E. coli types. However, 16% of VTEC strains isolated from healthy goats belonged to serotypes associated with haemolytic uraemic syndrome in humans. The ehxA gene was detected in 84.9 and 52.9% of the VTEC and EPEC from goats, respectively. The beta1, theta/gamma2 and zeta were the most frequent intimin types among the 17 EPEC strains studied and the most prevalent serotypes of these strains were O156:H25 and O177:H11. Our data show that in Spain healthy goats are an important reservoir of VTEC and EPEC, and a potential source of infection for humans. 相似文献
11.
A total of 147 dogs and 85 cats was surveyed for faecal carriage of thermophilic Campylobacters. Isolates were obtained from 33 (22.4 %) of the dogs and from 10 (11.8 %) of the cats investigated. The isolation rates recorded for diarrhoeic and non-diarrhoeic dogs and cats were not significantly different. Likewise, Campylobacters were isolated with about equal frequencies from puppies and mature dogs as well as from bitches and male dogs. Nineteen canine and 7 feline strains were biotyped and serotyped. A large majority (88.5 %) of these 26 strains belonged to serotypes previously recovered from human G. coli and C. laridis constituted 7.7 % and 3.8 %, respectively. Three strains belonged to serotypes previously recovered from human patients in Norway. 相似文献
12.
Production of toxins by Escherichia coli strains isolated from calves with diarrhoea in galicia (north-western Spain) 总被引：11，自引：0，他引：11
J Blanco E A González S García M Blanco B Regueiro I Bernárdez 《Veterinary microbiology》1988,18(3-4):297-311
A total of 289 Escherichia coli colonies isolated from 78 diarrhoeic calves were studied for production of heat-labile (LT) and heat-stable (STa) enterotoxins, verotoxin (VT), cytotoxic necrotizing factor (CNF) and K99 antigen, and they were serotyped. Production of STa was detected in a single strain possessing both K99 and F41 antigens; the serotype was 09:K (A) 35. LT-producing strains were not detected. From 16 (20.5%) calves, 51 VT-producing colonies of E. coli were isolated. Production of the necrotic factor was detected in 33 E. coli colonies isolated from 14 (17.9%) calves. Serotype was a useful marker for production of VT and CNF. Among the 51 VT-producing colonies, 24 were untypable and the remainder belonged to serotypes O2:K?, O103:K--, O104:K?, O128:K?, O153:K-- and O157:K--:H7. Four of the 33 CNF-producing colonies were untypable and the majority of the remaining colonies belonged to serotypes O15:K14, O78:(K80), O123:K-- and O139:K--. Both VT and CNF were lethal for mice, but only CNF showed necrotizing reaction in rabbit skin. Our results indicate that VT-producing and CNF-producing E. coli strains are frequently isolated from diarrhoeic calves and that according to the serotypes exhibited, some of them might be considered potential pathogens for humans. The role of VT-producing and CNF-producing strains in calf diarhoea remains to be established. 相似文献
13.
Fimbriae, toxins and pathogenicity islands (PAIs) are main virulence factors of the pathogenic Escherichia coli strains. To investigate into their prevalence in clinical E. coli isolates associated with porcine postweaning diarrhea (PWD) and/or pig edema disease (ED), 240 isolates were obtained from diseased piglets (140 from PWD, 76 from ED and 24 from ED/PWD) and submitted to PCR detection for genes coding for fimbriae, enterotoxins, shiga toxins, intimin and high-molecular-weight protein 2 (HMWP2). Among the 240 isolates detected, detection rates of the genes for F18, F4, intimin, HMWP2, Stx2e, LTa, STa and STb were 26.25%, 3.75%, 28.33%, 16.67%, 35%, 10.83%, 14.58% and 9.17%, respectively, and 67.92% of the isolates could be assigned into 20 different virulence factor patterns. Further more, F18ab+ STEC are the prevalent pathogens of ED, and F18+ and/or intimin+ STEC/ETEC are the dominant pathogens of ED/PWD, while F18ab+, F4+ and/or intimin+ ETEC and HPI+ and/or LEE+ E. coli are more frequently associated with PWD. 相似文献
14.
仔猪腹泻致病性大肠杆菌分型鉴定及耐药性分析 总被引：1，自引：1，他引：0
为了解贵州省规模化养猪场腹泻仔猪致病性大肠杆菌流行情况及耐药性变化,本研究运用凝集试验、PCR和药敏纸片琼脂扩散法等方法对分离的78株致病性大肠杆菌进行血清型、毒力基因及耐药性分析。结果显示,78株致病性大肠杆菌以O138、O87血清型为主,占定型菌株的60.8%;其中62株致病性大肠杆菌检出毒力基因,检出率为79.5%,可分为8种毒力基因类型,分属肠致病性大肠杆菌（EPEC）、肠产毒性大肠杆菌（ETEC）和肠聚集性大肠杆菌（EAEC）,毒力基因eaeA、elt和escV检出率较高,分别为38.5%、28.2%和21.8%;分离到的致病性大肠杆菌对β-内酰胺类药物高度耐药,均为多重耐药株,耐药种类可达8种以上。结果表明,当前贵州省规模化养猪场腹泻仔猪致病性大肠杆菌的毒力基因检出率较高且基因型复杂,耐药性严重。本试验结果可为规模化养猪场防控仔猪腹泻提供基础资料及理论依据。 相似文献
15.
Serotypes,phage types and virulence genes of shiga-producing Escherichia coli isolated from sheep in Spain 总被引：3，自引：0，他引：3
Rey J Blanco JE Blanco M Mora A Dahbi G Alonso JM Hermoso M Hermoso J Alonso MP Usera MA González EA Bernárdez MI Blanco J 《Veterinary microbiology》2003,94(1):47-56
PROBLEM ADDRESSED: Shiga toxin-producing Escherichia coli (STEC), have emerged as food poisoning pathogens which can cause severe diseases in humans. OBJECTIVE: The aim of this study was to determinate the serotypes and virulence genes of STEC strains isolated from sheep in Spain, with the purpose of determining whether sheep represent a potential source of STEC pathogenic for humans. METHODS AND APPROACH: Faecal swabs obtained from 697 healthy lambs on 35 flocks in Spain during the years 2000 and 2001 were examined for STEC using phenotypic (Vero cells) and genotypic (PCR) methods. RESULTS: STEC O157:H7 strains were isolated from seven (1%) animals in six flocks, whereas non-O157 STEC strains were isolated from 246 (35%) lambs in 33 flocks. A total of 253 ovine STEC strains were identified in this study. PCR showed that 110 (43%) strains carried stx(1) genes, 10 (4%) possessed stx(2) genes and 133 (53%) both stx(1) and stx(2). Enterohaemolysin (ehxA) and intimin (eae) virulence genes were detected in 120 (47%) and in 9 (4%) of the STEC strains. STEC strains belonged to 22 O serogroups and 44 O:H serotypes. However, 70% were of one of these six serogroups (O6, O91, O117, O128, O146, O166) and 71% belonged to only nine serotypes (O6:H10, O76:H19, O91:H-, O117:H-, O128:H-, O128:H2, O146:H21, O157:H7, O166:H28). A total of 10 new O:H serotypes not previously reported in STEC strains were found in this study. Seven strains of serotype O157:H7 possessed intimin type gamma1, and two strains of serotype O156:H- had the new intimin zeta. STEC O157:H7 strains were phage types 54 (four strains), 34 (two strains) and 14 (one strain). CONCLUSIONS: This study confirms that healthy sheep are a major reservoir of STEC pathogenic for humans. However, because the eae gene is present only in a very small proportion of ovine non-O157 STEC, most ovine strains may be less pathogenic. 相似文献
16.
Mercado EC Gioffré A Rodríguez SM Cataldi A Irino K Elizondo AM Cipolla AL Romano MI Malena R Méndez MA 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2004,51(2):82-88
Faecal samples from 76 diarrhoeic calves belonging to 36 farms located in the Pampas plain, Argentina, were examined for Shiga toxin-producing Escherichia coli (STEC). A total of 15 STEC strains were isolated from 12 (15.8%) calves which came from six different farms. All stx positive strains assayed by PCR were also positives in the Vero cell cytotoxicity test. The majority (60.0%) of the STEC strains carried the stx(1) gene. Twelve (80.0%) of the STEC isolates which belonged to serotypes O5:H- (n = 4), O26:H11 (n = 4), O26:H- (n = 1), O111:H- (n = 2), and O123:H38 (n = 1) were also enterohaemolysin (EHly) positive and carried the gene encoding for intimin (eae). All the stx positive strains were negative for the bfpA gene. Localized adherence to HEp-2 cells were observed in 83.3% of the eae+ STEC strains. STEC belonging to serotype O5:H- showed atypical biochemical properties, including urease production. Urease was also produced by two strains belonging to serotypes O153:H? and non-typeable, respectively. Resistance to three or more antibiotics was observed in 12 (80.0%) of the STEC isolates. Most of the serotypes of STEC recovered in this survey carried virulence traits that are associated with increased human and bovine pathogenicity. The present study shows that highly virulent STEC strains are being shed by diarrhoeic calves from farms located in a high incidence area of human STEC infections. 相似文献
17.
Bandyopadhyay S Mahanti A Samanta I Dutta TK Ghosh MK Bera AK Bandyopadhyay S Bhattacharya D 《Tropical animal health and production》2011,43(3):705-710
A total of 107 faecal samples were collected from diarrhoeic lambs of high altitude terrains (2,000 to 5,000 m above the mean
sea level) of Tawang and West Kameng districts of Arunachal Pradesh, India. Total 234 Escherichia coli were isolated and further subjected to PCR for the study of virulence repertoire characteristics of Shiga toxin-producing
E. coli (STEC) and enterotoxigenic E. coli (ETEC). Out of the 234 isolated E. coli, 32% were found positive for STEC, and 9% were carrying virulence gene for ETEC. The isolated STEC serogroups were O159,
O127, O120, O113, O60, O30, O25, O8 and O2. Of all the 74 STEC strains, PCR showed that 18% isolates carried stx
1
, 26% possessed stx
2
and 47% produced positive amplicon for both. Other virulent attributes like intimin (eaeA), enterohaemolysin (ehxA) and STEC auto-agglutinating adhesin (saa) were present in 18%, 43% and 44% of the isolates, respectively. The isolated ETEC serogroups were O172, O170, O159, O146,
O127, O120, O113, O86, O75, O60, O30, O25, O8, O2, OR and OUT. Of the 22 ETEC-positive isolates, 23%, 18% and 4.5% possessed
the gene only for LT, STa and STb, respectively, whereas 54% carried genes for both LT and STb. Some serogroups of E. coli like O159, O127, O120, O113, O60, O30, O25, O8 and O2 possessed genes for both Shiga toxin and enterotoxin. This study is
the first report of ETEC isolation from diarrhoeic lambs in India. The moderately high proportion of STEC and ETEC in the
diarrhoeic lambs implicated that these animals are important reservoir of STEC and ETEC. This is really a grave concern for
the ‘brokpas’ and nomads (shepherds) who share a close relationship with this animals for their livelihood. This study also
indicates that ETEC may be a major cause for frequent diarrhoeal episodes in lambs of this region. 相似文献
18.
Type II heat-labile enterotoxins (LT-II) have been reported in Escherichia coli isolates from humans, animals, food and water samples. The goal here was to determine the specific roles of the antigenically distinguishable LT-IIa and LT-IIb subtypes in pathogenesis and virulence of enterotoxigenic E. coli (ETEC) which has not been previously reported. The prevalence of genes encoding for LT-II was determined by colony blot hybridization in a collection of 1648 E. coli isolates from calves and pigs with diarrhea or other diseases and from healthy animals. Only five isolates hybridized with the LT-II probe and none of these isolates contained genes for other enterotoxins or adhesins associated with porcine or bovine ETEC. Ligated intestinal loops in calves, pigs, and rabbits were used to determine the potential of purified LT-IIa and LT-IIb to cause intestinal secretion. LT-IIa and LT-IIb caused significant secretion in the intestinal loops in calves but not in the intestinal loops of rabbits or pigs. In contrast, neonatal pigs inoculated with isogenic adherent E. coli containing the cloned genes for LT-I, LT-IIa or LT-IIb developed severe watery diarrhea with weight loss that was significantly greater than pigs inoculated with the adherent, non-toxigenic parental or vector only control strains. The results demonstrate that the incidence of LT-II appeared to be very low in porcine and bovine E. coli. However, a potential role for these enterotoxins in E. coli-mediated diarrhea in animals was confirmed because purified LT-IIa and LT-IIb caused fluid secretion in bovine intestinal loops and adherent isogenic strains containing cloned genes encoding for LT-IIa or LT-IIb caused severe diarrhea in neonatal pigs. 相似文献
19.
Khawaskar Damini P. Sinha D. K. Lalrinzuala Michael V. Athira V. Kumar Manish Chhakchhuak Lalsangzuala Mohanapriya K. Sophia I. Abhishek Kumar O. R. Vinodh Chaudhuri Pallab Singh B. R. Thomas Prasad 《Veterinary research communications》2022,46(2):353-362
Neonatal calf mortality is a major concern to livestock sector worldwide. Neonatal calf diarrhoea (NCD), an acute severe condition causes morbidity and mortality in calves. Amongst various pathogens involved in NCD, E. coli is considered as one of the major causes. The study was targeted to characterize E. coli isolates from neonatal calves for diarrhoeagenic Escherichia coli (DEC) types (pathotyping), antimicrobial resistance (AMR) profiling and to correlate with epidemiological parameters. From neonates, a total of 113 faecal samples were collected, out of that 308, lactose fermenting colonies were confirmed as E. coli. Pathotypable isolates (12.3%) were represented by STEC (6.1%), EPEC (2.9%), ETEC (1.9%), EAEC (0.9%) and EHEC (0.3%). Occurrence of STEC was more in non-diarrhoeic calves, whereas ETEC was observed more in diarrhoeic calves. EPEC occurrence was observed in both diarrhoeic and non-diarrhoeic calves. Fishers extract test showed no significant association for occurrence of DEC types to type of dairies, health status, species, breed, age and sex of neonatal calves. Two hundred and eighty isolates were tested for antimicrobial susceptibility. The isolates showed maximum resistance towards ampicillin (55.4%) followed by tetracycline (54.3%), while minimum resistance was observed towards meropenem (2.5%). Multidrug resistant E. coli isolates were found to be 139 (49.6%), and Extended-spectrum beta-lactamase (ESBL) producers were 120 (42.9%). DEC pathotypes like STEC, ETEC, EHEC and EAEC that are also multidrug resistant present in neonatal calves have zoonotic potential and hence are of public health significance.
相似文献20.
Nakazato G Gyles C Ziebell K Keller R Trabulsi LR Gomes TA Irino K Da Silveira WD Pestana De Castro AF 《Veterinary microbiology》2004,101(4):269-277
Escherichia coli isolates recovered from 182 fecal specimens from dogs up to five months old from the cities of S?o Paulo and Campinas, SP, Brazil, were examined by polymerase chain reaction (PCR) for several virulence factors and properties. The eae gene was found in 23 isolates of E. coli from 22 dogs, 19 of 146 (13%) from dogs with diarrhea and 3 of 36 (8.3%) from dogs with no diarrhea. Two different eae+ isolates were recovered from one dog with diarrhea. Isolates from two dogs with diarrhea harbored the bfpA gene, and none of the isolates possessed genes for enterotoxins, the EAF plasmid or Shiga toxins. PCR showed that, among the 23 isolates, eight were positive for beta intimin, six for gamma, two for, one for alpha, one for kappa, and five showed no amplification with any of the nine pairs of specific intimin primers used. PCR also showed that the LEE (locus of enterocyte effacement) was inserted in selC in four isolates, likely in pheU in seven isolates, and in undetermined sites in twelve isolates. Fifteen isolates adhered to HEp-2 cells and were fluorescence actin staining (FAS) positive. The predominant adherence pattern was the localized adherence-like (LAL) pattern. The eae-positive isolates belonged to a wide diversity of serotypes, including O111:H25, O119:H2 and O142:H6, which are serotypes that are common among human EPEC. These results confirmed the presence of EPEC in dogs (DEPEC) with and without diarrhea. The virulence factors found in these strains were similar to those in human EPEC, leading to the possibility that EPEC may move back and forth among human and canine populations. 相似文献