Longitudinal studies were done in two villages rural Bangladesh to learn more about the interactions between infectious diseases and the nutritional status of children. Diarrheal diseases, identified ...by surveillance of 197 children aged 2-60 months, were studied for bacterial, viral and parasitic enteropathogens in 1978-1979. The annual incidence of diarrhea was highest in children aged 2-11 months, and declined progressively with age from seven to four episodes per child per year. An enteropathogen was identified from rectal cultures taken during diarrhea in 51% of episodes and from 6% of monthly cultures taken when diarrhea was not present. Enterotoxigenic Escherichia coli were the pathogens found most frequently, followed by shigellae and rotaviruses. Diarrheal episodes associated with shigellae had the longest duration, while episodes associated with Vibrio cholerae or with rotavirus were more frequently associated with dehydration. E. coli diarrhea had a peak incidence during the hot months, and shigellosis was more frequent during the cool, dry months.
We compared the applicability of an enhanced chemiluminescent (ECL) method for using gene probes with that of radioactive probes to identify enterotoxigenic Escherichia coli (ETEC) in stools of ...Bangladeshi children with diarrhoea. Colony blots of E. coli isolates were hybridized using both α-32P-dCTP labelled and fluorescein-11-dUTP labelled polynucleotide and oligonucleotide gene probes for heat-labile enterotoxin (LT), and heat-stable enterotoxin (ST). Analysis of 1,620 isolates obtained from 540 patients gave similar results by both radioactive and chemiluminescent probes. The ECL method was faster than the radioactive method. Both polynucleotide and oligonucleotide probes could be used by the ECL method. Hybridization and detection by the ECL method appeared to be a convenient alternative to radioactive probes for screening E. coli isolates for ETEC.
Six hundred and seventy-five Escherichia coli isolates obtained from 225 diarrhoeal children less than five years of age were tested for adherence to HeLa cells and for hybridisation with DNA probes ...for genes conferring aggregative adherence (AggA), localised adherence (LA) and diffuse adherence (DA) to assess the usefulness of a recently developed DNA probe for AggA of enteroaggregative E. coli (EAggEC). The strains were further analysed with the DNA probes for heat-labile enterotoxin (LT), heat-stable enterotoxin (ST), Shiga-like toxins (SLT I and SLT II) and for enteroinvasiveness and adherent strains were all negative for these properties. The HeLa cell assay and DNA probe assays showed excellent agreement in identifying LA and DA positive isolates. However, significant disparities occurred in the case of AggA positive isolates, and the DNA probe failed to identify 31.9% (15 of 47) of the EAggEC identified by the HeLa cell adherence assay. The failure of the DNA probe to identify all the EAggEC indicated that there may be a high degree of genetic heterogeneity for the expression of AggA, and development of more DNA probes is necessary to detect all the possible genetic variants of EAggEC.
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