Prevalence of Enterotoxigenic Escherichia Coli Among Children Under Five Years in Siaya County, Western Kenya

Abstract

One of the most common causes of moderate to severe diarrhea among children and adults in developing countries is enterotoxigenic Escherichia coli (ETEC). It causes an estimated 400 million diarrheal episodes and 380,000 deaths globally in children less than 5 years of age annually in developing countries. Diarrhea in under-fives due to ETEC in Latin America is 34%, in Africa is 31% and in South Asia (Indian Subcontinent) is 31%. In Kenya, ETEC prevalence ranges from 1.5% to 10% yet there are insufficient data on ETEC and its enterotoxins associated with diarrhea in children in a rural setting as most previous studies have focused on the prevalence of ETEC in all age groups in urban settings. A recent study on diarrhea in Siaya County reported etiologies of diarrhea to be caused by nontyphoidal Salmonella, Campylobacter, Shigella, and rotavirus.The prevalence of ETEC was not reported.This was a case-control study carried out in Asembo, Karemo, and Gem sites in Siaya County, Kenya. The cases were children with diarrhea while controlswere those without diarrhea. This study aimed to investigate the prevalence of ETEC in children underfive years, characterize the ETECenterotoxins, and determine the enterotoxin associated with diarrhea in children underfive years in Siaya County. Three hundred and eighty-three (383)childrenunder five years of age who presented with moderate-severe diarrhea (cases) were enrolled at health facilities while 535 matched controls were enrolled at home within two weeks of case enrolment. Immediately after enrolment, stool swabs were collected from both cases and controls and transported to the laboratory within 18 hours. The stools were cultured on MacConkey for isolation and identification of E. coli colonies by morphologic and biochemical tests.Confirmed E. coli colonies were picked and tested by polymerase chain reaction (PCR) to identify ETEC heat-stable (ST) and heat-labile (LT) enterotoxins. Out of the 383 cases enrolled, 169 (44.1%) were females, 214 (55.9%) males. Out of 535 controls, females were 242 (45.2%) and males 293 (54.8%). The participants were categorized by age as 0-11 months 154 (40.2%) cases and 168 (34.6%) controls, 12-23 months were 131 (34.2%) cases and 175 (36%) controls, and 24-59 months were 98 (25.6%) cases and 143 (29.4%) controls. The median age was 14 months for cases and 16 months for controls. The overall prevalence of ETEC was 11%, 13.6% in cases, and9.2% in controls. The difference in prevalence among cases and controls was statistically significantp = 0.035. ETEC infection was higher in children less than 23 months than those above 24 months 38(13.3%) and 14(14.3%),respectively, in cases and 38(9.9%) and 11(22.6%) respectively in controls. ETEC enterotoxin distributions were as follows: LT only 19(5%), 27 (7.1%) ST only and 6 (1.67%) LT/ST in cases while LT only 17(3.2%), 23 (4.3%) ST only and 9 (1.7%) LT/ST in controls. There was no ETEC enterotoxin associated with diarrhea, however, ST-only enterotoxin was the most detected in both children with and those without diarrhea. The majority of the diarrheal children produced non-bloody, mucoid thick liquid stool without pus. The results from this study havesignificancein providing a better view of the prevalence of ETEC variants and their toxins distribution. This study has also indicated that ETEC should be included in routine laboratory testswhen determining the etiologies of diarrhea in children under five years. The high ETEC prevalence from this study points to higher contamination of the environment with ETEC and its enterotoxins hence, have significance in providing a better view of the prevalence of ETEC variants and their toxins and mapping out future studies in the country using modern molecular techniques. The controls should be studied further to find out if they developed diarrhea. More research on ETEC related diarrheal studies need to be conducted in children with and without diarrhea to give more insight on ETEC related diarrhea in Kenya for policy formation.