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INTRODUCTION: Enteropathogenic Escherichia coli (EPEC) causes infectious diarrhea among children in developing countries. However, in Nigeria, due to limited laboratory resources, the genetic diversity of its virulence factors, which includes its intimin subtypes remain undefined. This study aims to evaluate the serotypes, antibiotic resistance and the intimin subtypes genes associated with EPEC strains isolated from children with acute diarrhea in Abuja, Nigeria. METHODOLOGY: EPEC isolates from diarrheic children aged 0-60 months in Abuja, Nigeria were analyzed. PCR for EPEC virulence gene, Hep-2 cell Adherence and serotyping were performed. EPEC strains were further subtyped by PCR reactions for the identification of intimin subtype genes: α (alpha), ß (beta), γ1 (gamma-1), and Î (epsilon). Antibiotic resistance and ESBL production was determined by CLSI guidelines. RESULTS: Overall, 18 (4.5%) out of 400 children with acute diarrhea had EPEC infection. Typical EPEC strains were detected in 14 (3.5%) whereas 4 (1.1%) were atypical EPEC. Fifteen (83.3%) of the EPEC isolated belonged to ß intimin subtype gene, while the remaining 3 EPEC isolates possessed the intimin Î subtype. No α and γ intimin subtypes were detected. Traditional EPEC serotypes O114:H14 were detected only in tEPEC strains. Marked resistant to ß-lactam agents were observed but no ESBL-producing tEPEC or aEPEC was detected. CONCLUSIONS: This is the first report of intimin subtype genes in Abuja, Nigeria. These data will be useful in facilitating the characterization of intimin variants of EPEC and some Shiga toxin-producing E. coli (STEC) in humans and other animal species.
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AIM: The present study was conducted to find the association among virulence determinants of verotoxic Escherichia coli (VTEC) isolated from cattle calf feces. MATERIALS AND METHODS: A total of 216 cattle calf fecal samples were collected aseptically and processed under required conditions for the isolation of E. coli. The isolates were further subjected to multiplex polymerase chain reaction (mPCR) for the detection of virulent genes. All the VTEC isolates were serotyped at the Central Research Institute, Kasauli, Himachal Pradesh. The VTEC isolates were observed for the enterohemolysin production on washed sheep blood agar (wSBA). RESULTS: A total of 177 presumptive E. coli were isolated from 216 calf fecal samples revealing an overall prevalence of E. coli to be 81.94%. A total of 32 (14.81%) isolates were detected as VTEC through mPCR. The prevalence of verotoxin genes vt1, vt2, and combination of vt1+vt2 in the VTEC isolates was found to be 12 (37.5%), 14 (43.75%), and 6 (18.75%), respectively. Other virulent genes eaeA and hlyA were found in 6 and 11 VTEC strains with prevalence values of 18.75% and 34.37%, respectively. A total of 13 different O serogroups were revealed in serotyping of 32 VTEC isolates. Out of 32 VTEC strains, only 26 (81.25%) were enterohemolytic on wSBA as they produced the characteristic small, turbid zone of hemolysis around the streaking line. Although enterohemolysin production has been attributed to the presence of hlyA gene, only 11 of 26 enterohemolysin producing VTEC were found to be harboring the hlyA gene (11/26) 42.03%. CONCLUSION: The present study concludes that there might be an association between the presence of verotoxin genes and enterohemolysin production in VTEC group of E. coli.
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Raw meat can harbor pathogenic bacteria, potentially harmful to humans such as Escherichia coli O157:H7 causing diarrhea and hemolytic-uremic syndrome (HS). Therefore, the current study was carried out to evaluate the prevalence and the molecular detection characterization of E. coli serotype O157:H7 recovered from raw meat and meat products collected from Saudi Arabia. During the period of 25th January 2013 to 25th March 2014, 370 meat samples were collected from abattoirs and markets located in Riyadh, Saudi Arabia "200 raw meat samples and 170 meat products". Bacteriological analysis of the meat samples and serotyping of the isolated E. coli revealed the isolation of 11 (2.97%) strains of E. coli O157:H7. Isolation of E. coli O157:H7 in raw beef, chicken and mutton were 2%, 2.5%, and 2.5%, respectively, however, there was no occurrence in raw turkey. The incidences of E. coli O157:H7 in ground beef, beef burgers, beef sausage, ground chicken and chicken burgers were 5%, 10%, 0.0%, 5% and 0.0%, respectively. The multiplex PCR assay revealed that 3 (27.27%) out of 11 E. coli O157:H7 isolates from raw beef, chicken and mutton had stx1, stx2, and eae while 5 (45.45%) E. coli O157:H7 isolates from ground beef, ground chicken, and raw beef had both stx1 and stx2. However, from beef burgers, only one E. coli O157:H7 isolate had stx1 while two were positive for hlyA gene. These results call for urgent attention toward appropriate controls and good hygienic practices in dealing with raw meat.
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Shiga toxin-producing Escherichia coli (STEC) strains are considered as one of the major food-borne disease agents in humans worldwide. STEC strains, also called verotoxin-producing E. coli strains. The objectives of the present study were serotyping and molecular characterization of shiga toxigenic E. coli associated with raw meat and milk samples collected from Riyadh, Saudi Arabia. A total of 540 milk samples were collected from 5 dairy farms and 150 raw meat samples were collected from different abattoirs located in Riyadh, Saudi Arabia. E. coli were recovered from 86 milk samples (15.93%), serotyping of E. coli isolates revealed, 26 (4.81%) strains O157: H7, 23 (4.26%) strains O111, 20 (3.70%) strains O113: H21, 10 (1.85%) strains O22: H8 and 7 (1.3%) strains O172: H21. Meanwhile, 17 (11.33%) strains of E. coli were recovered from raw meat samples, serotyping of E. coli isolates revealed, 6 (4%) strains O157: H7, 5 (3.33%) strains O111 and 4 (2.67%) strains O174: H2 and only two (1.33%) strains were identified as O22: H8. Shiga toxin2 was detected in 58 (67.44%) serotypes of E. coli recovered from milk samples and 16 (94.12%) serotypes of E. coli recovered from meat samples, while intimin gene was detected in 38 (44.186%) serotypes of E. coli recovered from milk samples and in 10 (58.82%) serotypes of E. coli recovered from meat samples. The results of this study revealed the efficiency of combination between serotyping and molecular typing of E. coli isolates recovered from food of animal origin for rapid detection and characterization of STEC.