scholarly journals Prevalence, Virulence Genes and Antimicrobial Profiles of Escherichia Coli O157:H7 Isolated from Healthy Cattle

2021 ◽  
Author(s):  
Ghassan Tayh ◽  
Salma Mariem Boubaker ◽  
Rym Ben Khedher ◽  
Mounir Jbeli ◽  
Faten Ben Chehida ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Latex Agglutination ◽  
Human Consumption ◽  
Toxin Gene ◽  
Fecal Samples ◽  
E Coli ◽  
Food Borne ◽  
Healthy Cattle ◽  
Amoxicillin Clavulanic Acid

Abstract Background: Shiga toxin-producing Escherichia coli (STEC) O157:H7 is associated with intestinal infection in human and considered a main cause of food-borne diseases. It was isolated from animals, human and food. The aim of the study was to assess the incidence of E. coli O157:H7 in fecal samples of healthy cattle collected in slaughterhouses (n=160) and from farms (n=100).Methods: E. coli isolates were detected on MacConkey agar. A total of 236 E. coli isolates were recovered from fecal samples of healthy cattle. We used sorbitol MacConkey to detect non-sorbitol fermenting colonies that were examined for the presence of O157 antigen by latex agglutination, and positive bacteria were screened for the existence of stx1, stx2, eaeA and ehxA by PCR as well as rfbEO157 and fliCH7 genes specific for serotype O157. All isolates were examined for the susceptibility against 21antibiotics discs.Results: Of the 236 E. coli isolates, 4.2% (10/236) were positive for STEC O157:H7. Shiga toxin gene (stx2) was present in 70% of isolates, stx1 and ehxA were confirmed in 60% of the isolates, whereas eae was identified in two isolates. Other virulence factors screened (fimH, sfa/focDE, cdt3, traT, iutA and hly) were present among the 10 isolates. All E. coli O157:H7 isolates were sensitive to amoxicillin/clavulanic acid, cefotaxime, cefepime, aztreonam, colistin and sulfamethoxazole/trimethoprim. All isolates belong to the phylo-group E.Conclusion: This is the first study of the incidence of E. coli O157:H7 in cattle in Tunisia. Our finding proves the existence of STEC O157:H7 in healthy animals producing food for human consumption which could be a source of human contamination.

scholarly journals Occurrence, virulence genes, and antimicrobial profiles of Escherichia coli O157 isolated from ruminants slaughtered in Al Ain, United Arab Emirates

2020 ◽  
Author(s):  
Dawood Al-Ajmi ◽  
Shafeeq Rahman ◽  
Sharmila Banu
Keyword(s):  
Escherichia Coli ◽  
United Arab Emirates ◽  
Shiga Toxin ◽  
Meat Products ◽  
Immunomagnetic Separation ◽  
Latex Agglutination ◽  
Human Consumption ◽  
Fecal Samples ◽  
Chain Reactions ◽  
E Coli

Abstract Background: Shiga toxin-producing Escherichia coli (STEC) is a major source of food-borne illness around the world. E. coli O157 has been widely reported as the most common STEC serogroup and has emerged as an important enteric pathogen. Cattle, in particular have been identified as a major E. coli O157:H7 reservoir of human infections; however, the prevalence of this organism in camels, sheep, and goats is less understood. The aim of this study was to evaluate the occurrence and concentration of E. coli serotype O157 in the feces of healthy camels (n = 140), cattle (n =137), sheep (n = 141) and goats (n = 150) slaughtered in United Arab Emirates (UAE) for meat consumption between September 2017 and August 2018. We used immunomagnetic separation coupled with a culture-plating method to detect E. coli O157. Non-sorbitol fermenting colonies were assessed via latex-agglutination testing, and positive cultures were analyzed by performing polymerase chain reactions to detect genes encoding attaching and effacing protein (eaeA), hemolysin A (hlyA, also known as ehxA) and Shiga toxin (stx1 and stx2), and E. coli O157:H7 specific genes (rfb O157, uidA, and fliC). All E. coli O157 isolates were analyzed for their susceptibility to 20 selected antimicrobials.Results: E. coli O157 was observed in camels, goats, and cattle fecal samples at abundances of 4.3%, 2%, and 1.46%, respectively, but it was undetectable in sheep feces. The most prevalent E. coli O157 gene in all STEC isolates was stx2;, whereas, stx1 was not detected in any of the samples. The fecal samples from camels, goats, and cattle harbored E. coli O157 isolates that were 100% susceptible to cefotaxime, chloramphenicol, ciprofloxacin, norfloxacin, and polymyxin B.Conclusion: To our knowledge, this is the first report on the occurrence of E. coli O157 in slaughter animals in the UAE. Our results clearly demonstrate the presence of E. coli O157 in slaughtered animals, which could possibly contaminate meat products intended for human consumption.

scholarly journals Prevalence, molecular characterization and antimicrobial profiles of Enterohaemorrhagic E. coli O157 isolated from ruminants slaughtered in Al Ain, United Arab Emirates

2020 ◽  
Author(s):  
Dawood Al-Ajmi ◽  
Shafeeq Rahman ◽  
Sharmila Banu
Keyword(s):  
United Arab Emirates ◽  
Shiga Toxin ◽  
Meat Products ◽  
Immunomagnetic Separation ◽  
Latex Agglutination ◽  
Human Infection ◽  
Human Consumption ◽  
Fecal Samples ◽  
Sheep And Goats ◽  
E Coli

Abstract Background: Shiga toxin-producing Escherichia coli (STEC) are associated with major food illness around the world. E.coli O157, has been widely reported as the most common STEC serogroup, and has emerged as an important enteric pathogen. Further, cattle have been identified as a major E. coli O157:H7 reservoir for human infection; however, the ecology of this organism in camels, sheep and goats is less understood. The current study aims to evaluate the prevalence of E. coli serotype O157 in feces of cattle, camels, sheep and goats slaughtered in United Arab Emirates (UAE) for meat consumption. This study was carried out on fecal samples of healthy cattle (n = 137), camels (n = 140), sheep (n = 141) and goats (n = 150) during the period of September 2017 to August 2018. We have used the traditional sensitive immunomagnetic separation technique (IMS) coupled with a culture plating method for detection of E. coli O157. Non-sorbitol fermenting colonies were assessed via the latex agglutination test and the positive cultures were subjected to PCR for detection of attaching and effacing genes (eaeA), hemolysin A (hlyA) and Shiga toxin-producing genes (stx1 and stx2) and genes specific for E. coli O157:H7 (rfb O157, uid A and flic H7). All E. coli O157 isolates were analyzed for their susceptibility pattern toward 20 select antibiotics.Results: E. coli O157 was present in the fecal samples of goats, camels and cattle at 2%, 3.3%, and 1.6%, respectively. In sheep we failed to detect any E. coli O157 strains. The most prevalent E.coli O157 gene identified across all species’ isolates was stx2, while stx1 was not detected in any of the samples. ­After testing samples from camels, goats and cattle, Cefotaxime (100%), Chloramphenicol (100%), Ciprofloxacin (100%), Norfloxacin (100%) and Polymixin B (100%) showed susceptibility showed susceptibility to all E.coli O157 isolates.Conclusion: This is the first study, to our knowledge, to report on the prevalence of E. coli O157 in the slaughter animals in UAE and clearly demonstrates the presence of these pathogens in slaughtered animals, which could possibly contaminate the meat products intended for human consumption.

scholarly journals Prevalence and molecular detection of shiga toxin producing Escherichia coli from diarrheic cattle

2016 ◽  
Vol 14 (1) ◽  
pp. 63-68 ◽  
Author(s):  
MM Akter ◽  
S Majumder ◽  
KH MNH Nazir ◽  
M Rahman
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Molecular Detection ◽  
Chain Reaction ◽  
Specific Primers ◽  
Fecal Samples ◽  
E Coli ◽  
Uremic Syndrome ◽  
Polymerase Chain ◽  
Positive Isolate

Shiga toxin-producing Escherichia coli (STEC) are zoonotically important pathogen which causes hemorrhagic colitis, diarrhea, and hemolytic uremic syndrome in animals and humans. The present study was designed to isolate and identify the STEC from fecal samples of diarrheic cattle. A total of 35 diarrheic fecal samples were collected from Bangladesh Agricultural University (BAU) Veterinary Teaching Hospital. The samples were primarily examined for the detection of E. coli by cultural, morphological and biochemical characteristics, followed by confirmation of the isolates by Polymerase Chain Reaction (PCR) using gene specific primers. Later, the STEC were identified among the isolated E. coli through detection of Stx-1 and Stx-2 genes using duplex PCR. Out of 35 samples, 25 (71.43%) isolates were confirmed to be associated with E. coli, of which only 7 (28%) isolates were shiga toxin producers, and all of them were positive for Stx-1. However, no Stx-2 positive isolate could be detected. From this study, it may be concluded that cattle can act as a reservoir of STEC which may transmit to human or other animals.J. Bangladesh Agril. Univ. 14(1): 63-68, June 2016

scholarly journals Comparison between human and animal isolates of Shiga toxin-producing Escherichia coli O157 from Australia

2002 ◽  
Vol 128 (3) ◽  
pp. 357-362 ◽  
Author(s):  
N. FEGAN ◽  
P. DESMARCHELIER
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Human Infection ◽  
Pulsed Field Gel Electrophoresis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Animal Population ◽  
E Coli ◽  
Virulence Markers ◽  
Animal Isolates

There is very little human disease associated with enterohaemorrhagic Escherichia coli O157 in Australia even though these organisms are present in the animal population. A group of Australian isolates of E. coli O157:H7 and O157:H- from human and animal sources were tested for the presence of virulence markers and compared by XbaI DNA macrorestriction analysis using pulsed-field gel electrophoresis (PFGE). Each of 102 isolates tested contained the gene eae which encodes the E. coli attaching and effacing factor and all but one carried the enterohaemolysin gene, ehxA, found on the EHEC plasmid. The most common Shiga toxin gene carried was stx2c, either alone (16%) or in combination with stx1 (74%) or stx2 (3%). PFGE grouped the isolates based on H serotype and some clusters were source specific. Australian E. coli O157:H7 and H- isolates from human, animal and meat sources carry all the virulence markers associated with EHEC disease in humans therefore other factors must be responsible for the low rates of human infection in Australia.

scholarly journals Molecular analysis of Escherichia coli O157 strains isolated from cattle and pigs by the use of PCR and pulsed-field gel electrophoresis methods

2012 ◽  
Vol 47 (No. 6) ◽  
pp. 149-158 ◽  
Author(s):  
J. Osek ◽  
P. Gallien
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Genetic Relatedness ◽  
Rflp Analysis ◽  
Toxin Gene ◽  
Escherichia Coli O157 ◽  
Chromosomal Dna ◽  
E Coli ◽  
Shiga Toxin Genes ◽  
Porcine Origin

Fourteen Escherichia coli O157 strains isolated from cattle and pigs in Poland and in Germany were investigated, using PCR, for the genetic markers associated with Shiga toxin-producing E. coli (STEC). Only two strains, both of cattle origin, were positive for the fliC (H7) gene and could be classified as O157 : H7. Nine isolates had stx shiga toxin genes, either stx1 (1 strain), stx2 (4 isolates) or both (4 strains). The stx2-carrying samples were further subtyped by PCR for the stx2c, stx2d, and stx2e toxin variants. It was shown that all but one stx2-positive bacteria possessed the stx2c Shiga toxin gene type and one stx2 STEC isolate had the stx2d virulence factor sub-type. The eaeA (intimin) gene was found in 9 strains (8 isolates from cattle and one strain from pigs); all of them harboured the genetic marker characteristic of the gamma intimin variant. The translocated intimin receptor (tir) gene was detected in 7 isolates tested and among them only one tir-positive strain was recovered from pigs. The ehly E. coli enterohemolysin gene was amplified in all but one strains obtained from cattle and only in one isolate of porcine origin. The genetic relatedness of the analysed E. coli O157 strains was examined by restriction fragment length polymorphism (RFLP) of chromosomal DNA digested with XbaI. Two distinct but related RFLP pattern clusters were observed: one with 9 strains (8 isolates of bovine origin and one strain obtained from pigs) and the other one comprises the remaining 5 E. coli isolates (4 of porcine origin and one strain recovered from cattle). The results suggest that pigs, besides cattle, may be a reservoir of E. coli O157 strains potentially pathogenic to humans. Moreover, epidemiologically unrelated isolates of the O157 serogroup, recovered from different animal species, showed a clonal relationship as demonstrated by the RFLP analysis.

Detection of cytolethal distending toxin and other virulent factors in Escherichia coli samples from animal livestock, retail foods and gastroenteritis human cases in Qatar

2020 ◽  
Author(s):  
Adriana Morales Gómez ◽  
Nilda N. Valenzuela ◽  
Kenlyn E. Peters ◽  
Ahmed Salem ◽  
Ali Sultan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Food Products ◽  
Cross Sectional Study ◽  
Toxin Gene ◽  
Cytolethal Distending Toxin ◽  
Cross Sectional ◽  
E Coli ◽  
Polymerase Chain ◽  
Retail Food

Cytolethal distending toxin (CDT) is a heterotrimeric AB-type genotoxin produced by several clinically important bacterial pathogens. To better understand the risk of CDT within the food supply and human gastroenteritis patients in Qatar, we investigated the frequency of the CDT gene (cdtB) among Escherichia coli (E. coli) strains recovered from food products, animal livestock, and human gastroenteritis patients. In this cross-sectional study, E. coli isolates were screened for cdtB using polymerase chain reaction (PCR). cdtB positive strains were further examined for E. coli cdtB gene types (cdt I, cdt II, cdt III, cdt IV and cdtV), serotypes O157: H7, and non-O157 Shiga toxin-producing E. coli O26, O45, O103, O111, O121, and O145. Screening for other virulent factors, stx (Shiga toxin gene) and eae (gene that encodes intimin) genes were also performed. The cdtB gene was detected in E. coli isolates sourced from all three groups; animal livestock (17%), retail foods (8%), and human gastroenteritis patients (3%). Although the incidence of cdtB gene harboring E. coli is relatively low among gastroenteritis patients, there is still a risk of infection from animal reservoirs as well as retail food products. Among the three groups, E. coli isolates from humans had the lowest occurrence of cdtB, stx, eae, and O157: H7. Furthermore, we advise implementing monitoring at the food production and preparation level.

scholarly journals Shiga Toxin Gene Loss and Transfer In Vitro and In Vivo during Enterohemorrhagic Escherichia coli O26 Infection in Humans

2007 ◽  
Vol 73 (10) ◽  
pp. 3144-3150 ◽  
Author(s):  
Martina Bielaszewska ◽  
Rita Prager ◽  
Robin Köck ◽  
Alexander Mellmann ◽  
Wenlan Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gene Loss ◽  
Pulsed Field Gel Electrophoresis ◽  
Enterohemorrhagic Escherichia Coli ◽  
Toxin Gene ◽  
Shiga Toxins ◽  
E Coli

ABSTRACT Escherichia coli serogroup O26 consists of enterohemorrhagic E. coli (EHEC) and atypical enteropathogenic E. coli (aEPEC). The former produces Shiga toxins (Stx), major determinants of EHEC pathogenicity, encoded by bacteriophages; the latter is Stx negative. We have isolated EHEC O26 from patient stools early in illness and aEPEC O26 from stools later in illness, and vice versa. Intrapatient EHEC and aEPEC isolates had quite similar pulsed-field gel electrophoresis (PFGE) patterns, suggesting that they might have arisen by conversion between the EHEC and aEPEC pathotypes during infection. To test this hypothesis, we asked whether EHEC O26 can lose stx genes and whether aEPEC O26 can be lysogenized with Stx-encoding phages from EHEC O26 in vitro. The stx 2 loss associated with the loss of Stx2-encoding phages occurred in 10% to 14% of colonies tested. Conversely, Stx2- and, to a lesser extent, Stx1-encoding bacteriophages from EHEC O26 lysogenized aEPEC O26 isolates, converting them to EHEC strains. In the lysogens and EHEC O26 donors, Stx2-converting bacteriophages integrated in yecE or wrbA. The loss and gain of Stx-converting bacteriophages diversifies PFGE patterns; this parallels findings of similar but not identical PFGE patterns in the intrapatient EHEC and aEPEC O26 isolates. EHEC O26 and aEPEC O26 thus exist as a dynamic system whose members undergo ephemeral interconversions via loss and gain of Stx-encoding phages to yield different pathotypes. The suggested occurrence of this process in the human intestine has diagnostic, clinical, epidemiological, and evolutionary implications.

scholarly journals Molecular Characterization of Shiga Toxin-Producing Escherichia coli Strains Isolated in Poland

2016 ◽  
Vol 65 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Aleksandra Januszkiewicz ◽  
Waldemar Rastawicki
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Virulence Gene ◽  
Virulence Determinants ◽  
E Coli ◽  
Heat Stable ◽  
Food Borne ◽  
Wide Range ◽  
Uremic Syndrome

Shiga toxin-producing Escherichia coli (STEC) strains also called verotoxin-producing E. coli (VTEC) represent one of the most important groups of food-borne pathogens that can cause several human diseases such as hemorrhagic colitis (HC) and hemolytic – uremic syndrome (HUS) worldwide. The ability of STEC strains to cause disease is associated with the presence of wide range of identified and putative virulence factors including those encoding Shiga toxin. In this study, we examined the distribution of various virulence determinants among STEC strains isolated in Poland from different sources. A total of 71 Shiga toxin-producing E. coli strains isolated from human, cattle and food over the years 1996 – 2010 were characterized by microarray and PCR detection of virulence genes. As stx1a subtype was present in all of the tested Shiga toxin 1 producing E. coli strains, a greater diversity of subtypes was found in the gene stx2, which occurred in five subtypes: stx2a, stx2b, stx2c, stx2d, stx2g. Among STEC O157 strains we observed conserved core set of 14 virulence factors, stable in bacteria genome at long intervals of time. There was one cattle STEC isolate which possessed verotoxin gene as well as sta1 gene encoded heat-stable enterotoxin STIa characteristic for enterotoxigenic E. coli. To the best of our knowledge, this is the first comprehensive analysis of virulence gene profiles identified in STEC strains isolated from human, cattle and food in Poland. The results obtained using microarrays technology confirmed high effectiveness of this method in determining STEC virulotypes which provides data suitable for molecular risk assessment of the potential virulence of this bacteria.

scholarly journals Shiga toxin-producing Escherichia coli (STEC) food-borne outbreaks

2017 ◽  
Vol 63 (1) ◽  
pp. 45 ◽  
Author(s):  
A. PEXARA (Α. ΠΕΞΑΡΑ) ◽  
A. S. ANGELIDIS (Α. Σ. ΑΓΓΕΛΙΔΗΣ) ◽  
A. GOVARIS (Α. ΓΚΟΒΑΡΗΣ)
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Intestinal Flora ◽  
Food Poisoning ◽  
Significant Risk ◽  
Public Health Problem ◽  
Human Infection ◽  
Food Sources ◽  
E Coli ◽  
Food Borne

Escherichia coli (E. coli) are Gram negativo, non-sporulating bacteria, which belong to the normal intestinal flora of humans and animals. Shiga toxin-producing E. coli (STFC) arc a group of if. coli that is defined by the capacity to produce toxins called Shiga toxins (Stx). hollowing ingestion of STEC, the significant risk of two serious and potentially life-threatening complications of infection, hemorrhagic colitis and hemolytic uremic syndrome (HUS), makes STHC food poisoning a serious public health problem. Besides Stx, human pathogenic STFC harbor additional virulence factors that are important for their pathogenicity. Although human infection may also be acquired by direct transmission from person to person or by direct contact of humans with animal carriers, the majority of STFC infections are food-borne in origin.The gastrointestinal tract of healthy ruminants seems to be the foremost important reservoir for STFC and ingestion of undercooked beef one of the most likely routes of transmission to humans, Other important food sources include faecally contaminated vegetables and drinking water, The serogroup classification of STHC is based on the somatic (O) and flagellar (H) antigens, and, to date, more than 200 STFC serogroups have been identified, Human STFC infections are, however, associated with a minor subset of 0;H serotypes. Of these, the 0157:H7 or the 0157 :H- serogroups (STFC 0157) are the ones most frequently reported to be associated with food-borne outbreaks. However other non-0157 STFC serogroups such as E. coli 026, 0103, O l l i , 012I, 045 and 0145 have caused several outbreaks in recent years.Two outbreaks of gastroenteritis caused by E. coli 0157:117 were first reported in the US, following the consumption of undercooked hamburgers, in 1982. Since then several outbreaks were reported worldwide. A major E. coli 0157:117 outbreak occurred in Japan and contaminated radish sprouts was identified as the vehicle of infection. More than 6,000 school children were affected, 101 people were hospitalized with lILS and 12 deaths were recorded. The recent outbreak of STFC 0104:114 infection and HUS reported in Germany in the spring of 2011 was one of the largest outbreaks worldwide. As of 27 July, 3 126 cases of STFC infections, 773 cases of HUS including 46 deaths linked to the outbreak in Germany and occurring in the Furopean Union (FU) (including Norway), Outside the FU 8 cases of STFC and 5 cases of HUS, including 1 death have been reported in the USA, Canada and Switzerland, all with recent travel history to Germany.The present review on major STliC food-borne outbreaks recorded worldwide highlights the need for eontrol measures in order to prevent or at least minimize the occurrence of similar events in the future.

Escherichia coli O157 and non-O157 Shiga Toxin–Producing Escherichia coli in Fecal Samples of Finished Pigs at Slaughter in Switzerland

2006 ◽  
Vol 69 (2) ◽  
pp. 260-266 ◽  
Author(s):  
M. KAUFMANN ◽  
C. ZWEIFEL ◽  
M. BLANCO ◽  
J. E. BLANCO ◽  
J. BLANCO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Escherichia Coli O157 ◽  
Strongly Correlated ◽  
Fecal Samples ◽  
E Coli ◽  
High Prevalence ◽  
Strain Testing ◽  
Typical Epec ◽  
Uremic Syndrome

Fecal samples from 630 slaughtered finisher pigs were examined by PCR to assess the shedding of Escherichia coli O157 (rfbE) and Shiga toxin–producing E. coli (STEC, stx). The proportion of positive samples was 7.5% for rfbE and 22% for stx. By colony hybridization, 31 E. coli O157 and 45 STEC strains were isolated, and these strains were further characterized by phenotypic and genotypic traits. Among E. coli O157 strains, 30 were sorbitol positive, 30 had an H type other than H7, and none harbored stx genes. Intimin (eae), enterohemolysin (ehxA), EAST1 (astA), and porcine A/E–associated protein (paa) were present in 10, 3, 26, and 6% of strains. Among them, one eae-γ1–positive O157:H7 strain testing positive for ehxA and astA and two eae-α1–positive O157:H45 strains were classified as enteropathogenic E. coli (EPEC). The O157:H45 EPEC harbored the EAF plasmid and the bfpA gene, factors characteristic for typical EPEC. The isolated STEC strains (43 sorbitol positive) belonged to 11 O:H serotypes, including three previously reported in human STEC causing hemolytic uremic syndrome (O9:H−, O26:H−, and O103:H2). All but one strain harbored stx2e. The eae and ehxA genes, which are strongly correlated with human disease, were present in only one O103:H2 strain positive for stx1 and paa, whereas the astA gene was found more frequently (14 strains). High prevalence of STEC was found among finisher pigs, but according to the virulence factors the majority of these strains seem to be of low virulence.

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