Molecular and phenotypic typing of enteropathogenic Escherichia coli isolated in childhood acute diarrhea in Abuja, Nigeria.

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 έ (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 έ 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.

Diarrheagenic Escherichia coli pathotypes isolated from children with diarrhea in the Federal Capital Territory Abuja, Nigeria.

INTRODUCTION: Escherichia coli are frequently isolated from diarrheic children in the Federal Capital Territory Abuja, Nigeria, but their virulent properties are not routinely evaluated. Therefore, the etiology of childhood diarrheal disease attributable to diarrheagenic Escherichia coli (DEC) in Abuja, Nigeria remains unknown. METHODOLOGY: Stool specimens from 400 acute diarrheic children between 0 and 60 months of age were studied. E. coli strains isolated were evaluated by polymerase chain reaction (PCR) for nine virulence genes and HEp-2 cell adherence to detect and identify five distinct diarrheagenic E. coli categories. RESULTS: Diarrheagenic E.coli was detected in 51 (12.8%) of the diarrheic children. The observed DEC pathotypes were enteropathogenic E. coli (EPEC) in 18 (4.5%) children, enterotoxigenic E. coli (ETEC) in 16 (4.0%), enteroaggrative E. coli (EAEC) in 8 (2.0%), enterohaemorrhagic E. coli (EHEC) in 6 (1.5%), and enteroinvasive E. coli (EIEC) in 3 (0.8%). Four (1.0 %) EPEC strains with only the eae+ gene that adhered diffusely to HEp-2 cell were identified as atypical EPEC. All the DEC categories except atypical EPEC were identified in children between 6 and 12 months of age. CONCLUSIONS: This study underscores the need for routine evaluation of diarrheic children for virulence properties of infectious DEC. Atypical EPEC are emerging among the DEC pathotypes isolated from childhood acute gastroenteritis in Abuja, Nigeria.

Molecular characterization and antibiotic resistance of Salmonella in children with acute gastroenteritis in Abuja, Nigeria.

INTRODUCTION: In Nigeria, acute gastroenteritis in children under five years of age is a major cause of mortality and morbidity; identification and characterization of microbial agents of acute gastroenteritis, including Salmonella, remains a powerful tool for effective management, surveillance, and control. METHODOLOGY: Diarrheal stool samples were directly plated onto differential and selective media to isolate Salmonella. Extended-spectrum beta-lactamases were screened using the double disk diffusion technique and by PCR targeting the blaTEM and blaCTX-M genes. Pulsed-field gel electrophoresis (PFGE) was performed usingthe PulseNet Canada Laboratory protocol for molecular subtyping using the restriction enzymes XbaI and BlnI. RESULTS: The serotypes identified were Salmonella enterica serovar Zanzibar (n = 5), Salmonella Brancaster (n = 3), and one isolate of Salmonella Enteritidis (phage type 1). The following levels of resistance were found among the Salmonella strains: amoxicillin, five strains (55.6%); amoxicillin-clavulanic acid, two strains (22.2%); cephalexin, five strains (55.6%); and cefuroxime, five strains (55.6%). Intermediate resistance was found in five strains (55.6%) only to amoxicillin-clavulanic acid. All isolates were susceptible to nalidixic acid, ciprofloxacin, and ceftriaxone, and no ESBL-producing Salmonella were detected. CONCLUSIONS: Our findings demonstrated the involvement of three Salmonella serovars in acute gastroenteritis; resistance to penicillins and cephalosporins was common.