Disease Burden Due to Enterotoxigenic Escherichia coli in the First 2 Years of Life in an Urban Community in Bangladesh

Abstract

A cohort of 321 children was followed from birth up to 2 years of age to determine the incidence of enterotoxigenic Escherichia coli (ETEC) in Bangladesh. The average number of diarrheal days and incidence rates were 6.6 and 2.3/child/year, respectively. ETEC was the most common pathogen and was isolated in 19.5% cases, with an incidence of 0.5 episode/child/year. The prevalence of rotavirus diarrhea was lower (10%). ETEC expressing the heat-stable enterotoxin (ST) was predominant. Strains isolated from diarrheal cases were positive for colonization factors (CFs) in higher frequency (66%) than from healthy children (33%) (P < 0.001). The heat-labile toxin (LT)-positive strains from healthy children were more often CF negative (92%) than those isolated from children with diarrhea (73%) (P < 0.001). In children with symptomatic or asymptomatic infections by CFA/I, CS1 plus CS3, CS2 plus CS3, or CS5 plus CS6 strains, a repeat episode of diarrhea or infection by the homologous CF type was uncommon. Repeat symptomatic infections were noted mostly for LTand ST-expressing ETEC. ETEC diarrhea was more prevalent in children in the A and AB groups than in those in the O blood group (P ‫؍‬ 0.032 to 0.023). Children with ETEC diarrhea were underweight and growth stunted at the 2-year follow-up period, showing the importance of strategies to prevent and decrease ETEC diarrheal morbidity in children.Enterotoxigenic Escherichia coli (ETEC) is a common cause of acute watery diarrhea in children in developing countries (25). ETEC is a multivalent pathogen producing the heatstable (ST) and/or heat-labile toxin (LT) as well as over 25 colonization factors (CFs). The ST phenotype of ETEC has been shown to be predominant (23,25), while the most common of the CFs are CFA/I and CS1 to CS6 (14,23,25,37). Studies in animals and in humans suggest that immunity against both LT and CFs may be important for protection against ETEC. However, results from different studies are conflicting regarding the relative importance of different toxin types and/or CFs on protection from further disease and infection (11,18,27,32), and data from different settings are needed to elucidate whether ETEC strains expressing these different virulence factors may prevent against repeated episodes of diarrhea. The first longitudinal study to determine the relationship between ETEC and other enteric pathogens and the incidence of diarrhea of children in a birth cohort was carried out in Mexico (10). In the present study, we have evaluated the natural history of ETEC infections, with emphasis on the different phenotypes, during the first 2 years of life in a birth cohort of 321 children in an urban slum area in Dhaka, Bangladesh. This included evaluation of the incidence, seasonality, and occurrence of symptomatic and asymptomatic ETEC infections. We have also evaluated whether blood group and nutritional factors may predispose to ETEC diarrhea. For comparison, we have also studied the incidence of other common enteric infections. MATERIALS AND METHODS Study popul...

Pathogenicity and Phenotypic Characterization of Enterotoxigenic Escherichia coli Isolates from a Birth Cohort of Children in Rural Egypt

“…Our findings are consistent with other studies that have reported a declining incidence of ETEC diarrhea with age and lower ratios of ETEC infections in symptomatic to asymptomatic children with increasing age (22). Studies have shown that natural protection against ETEC-associated diarrhea emerges in children who are exposed to repeated infections (23)(24)(25)(26)(27); however, natural protection does not prevent ETEC colonization.…”

“…These findings are of interest, given that current colonization factor-based vaccine approaches do not consider CS7 and CS14 (these factors cross-react immunologically with CS5 and CFA/I, respectively), which may be important causes of pediatric disease (35). Other CFA-toxin phenotype combinations, such as CFA/I-ST and CS5 LT/ST alone, were found in our study to be associated with diarrhea, as well as in a comparable cohort study (27). On the other hand, the combination of LT/ST and CS12 was not found to be associated with diarrhea.…”

“…ETEC isolates recovered from diarrheal cases were positive for CFAs at a higher frequency than were samples from healthy children; however, the proportion of the CFAs detected was much lower than that reported from another study in Bangladesh (27). The important role of CFAs was obvious in the pathogenicity of ETEC isolate-associated diarrhea; when combined with the expressed enterotoxins, the odds of inducing diarrhea increased in subsequent infections.…”

Causes of Impaired Oral Vaccine Efficacy in Developing Countries

“…HBGA phenotype also appears to influence susceptibility to bacterial enteropathogens [86,87], including V. cholerae [88,89]. Nonsecretors are more likely to suffer from severe cholera than secretors [90].…”

Effect of Bacteriophage in Enterotoxigenic <i>Escherichia coli</i> (ETEC) Infected Pigs

“…Enterotoxigenic Escherichia coli (ETEC) is a causative agent of diarrhea in neonatal and recently weaned pigs as well as humans [10,11]. Treatment of ETEC infection could be easily achieved by the administration of antibiotics, but antibiotic abuse may lead to adverse effects [16] such as antimicrobial resistance, which is a major threat to human health through drug resistance gene transfer.…”