Prevalence of diarrheagenic Escherichia coli strains detected by PCR in patients with travelers' diarrhea

Abstract

OBJECTIVE: To determine the prevalence of the different categories of diarrheagenic Escherichia coli, enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), verotoxin-producing E. coli (VTEC), enteroaggregative E. coli (EAggEC), diffusely adherent E. coli (DAEC), and enteropathogenic E. coli (EPEC), associated with travelers' diarrhea. METHODS: Stool specimens from 350 patients with travelers' diarrhea were collected between 1994 and 1996. The virulence factors of the diarrheagenic E. coli isolated were detected by PCR technique, in subcultures of single colonies of all morphotypes of E. coli observed in culture on MacConkey agar. RESULTS: ETEC (15.7%), EAggEC (13.4%) and DAEC (9.14%) are significantly more prevalent than EIEC (3.4%), EPEC (2.86%) and VTEC (0.86%) (p<0.05; z-test). The prevalence of ETEC and EAggEC was similar in all geographic areas visited. CONCLUSIONS: PCR is a rapid and specific technique to use in the identification of the different categories of diarrheagenic E. coli and greatly increases the yield of potential enteropathogens from cases of travelers' diarrhea. Not only ETEC but also EAggEC and DAEC strains play a major role in the etiology of travelers' diarrhea, whereas EIEC, EPEC, and VTEC strains play a minor role, leading to the question of whether it is necessary to search routinely for these three types of E. coli in diagnostic laboratories.

Clinical Study of Acute Childhood Diarrhoea Caused by Bacterial Enteropathogens

“…Shigella and Salmonella are least likely to cause infantile diarrhoea but their incidence increases with age. These findings are consistent with those of African studies [19,20]. This might be so because Salmonella are least likely to adapt to domesticated cattles and all varieties of fowls and chickens.…”

Susceptibility patterns of enteroaggregative Escherichia coli associated with traveller's diarrhoea: emergence of quinolone resistance

“…Single colony subcultures of all different lactose-fermenting colonial morphotypes growing on MacConkey agar were identi®ed by conventional criteria. These colonies were tested by PCR to detect EAggEC as described elsewhere [22].…”

Genotypic Characterization of Enterotoxigenic Escherichia coli Strains Causing Traveler's Diarrhea

“…TD was defined as the occurrence between 12 h after arrival in, and 5 days after departure from, the country visited; of three or more episodes of watery diarrhea within a 24-h period with or without other symptoms; or as the occurrence of unformed stools accompanied by one of the following: abdominal cramps, tenesmus, vomiting, nausea, fever, chills, or prostration. The presence of E. coli and other bacterial enteropathogens was determined by conventional methods, while PCR was used to detect enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), and ETEC (10). The presence of classical (LT, STh, STp, CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, CS7, CS8, CS12, CS14, CS17, CS18, CS19, CS20, and CS21) and nonclassical (Tia, LeoA, TibA, EatA, EAST1, and ECP) VFs was determined by PCR as previously described (11,12,13,14,15,16) (Table 1).…”