title: Etiology of acute diarrhea in children and adults in Tunis, Tunisia, with emphasis on diarrheagenic Escherichia coli: prevalence, phenotyping, and molecular epidemiology.
abstract: A total of 271 stool specimens were collected from children (diarrheagenic, n = 115 and control, n = 54) and adults (diarrheagenic, n = 73 and control, n = 29) from Tunis, Tunisia, and processed to detect bacterial enteropathogens, parasites, and viruses. Diarrheagenic Escherichia coli (DEC) were identified by their virulence genes (polymerase chain reaction) and adherence patterns (tissue culture assays). The most frequently isolated enteric pathogens from diarrheagenic children were enterotoxigenic E. coli (ETEC, 32.3%), enteroaggregative E. coli (EAEC, 11.3%), enteroinvasive E. coli (EIEC, (11.3%), adenovirus (10.4%), enterohemorrhagic E. coli (EHEC, 10.4%), and Salmonella spp. (9.5%). For children in the control group, ETEC (37%), EAEC (15%), EHEC (11.1%), and typical enteropathogenic E. coli (EPEC, 11.1%) were the most common enteric pathogens. In adults in the diarrheagenic group, Salmonella spp. (34.2%), ETEC (12.3%), adenovirus (7%), and Shigella spp. (4%) were the most common enteric pathogens. In adults in the control group, ETEC (31%) was the most common enteric pathogen. Multiple pathogens were recovered from 22% of the diarrheagenic children and 7% of the diarrheagenic adults. Escherichia coli strains showed high resistance rates to tetracycline, streptomycin, and beta-lactams. The most frequent combinations were ETEC-rotavirus and ETEC-adenovirus. Pulsed-field gel electrophoresis for DEC indicated a large number of DEC clones (five major clones) persistent in the community reservoir for a considerable period of time that caused diarrhea in the population. This suggests the confluence of small epidemics by clonally related DEC strains circulating in this region.
authors.affiliation: Laboratoire de Contrôle des Eaux et Denrées Alimentaires, Laboratoire de Virologie Clinique, et Laboratoire de Parasitologie Clinique, Institut Pasteur de Tunis, Tunis, Tunisia.
authors.forename: Nazek
authors.initials: N
authors.lastname: Al-Gallas
authors.forename: Olfa
authors.initials: O
authors.lastname: Bahri
authors.forename: Aida
authors.initials: A
authors.lastname: Bouratbeen
authors.forename: Assia
authors.initials: A
authors.lastname: Ben Haasen
authors.forename: Ridha
authors.initials: R
authors.lastname: Ben Aissa
mesh_terms: D000328:Adult; D017677:Age Distribution; D002648:Child; D004269:DNA, Bacterial; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology*; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D014644:Genetic Variation; D006801:Humans; D017720:Molecular Epidemiology; D015995:Prevalence; D012621:Seasons; D014416:Tunisia / Q000453:epidemiology