Enterotoxigenic Escherichia Coli Toxins and Colonization Factors Among Zambian Children Presenting with Moderate to Severe Diarrhea to Selected Health Facilities

Author(s): Michelo Simuyandi, Roma Chilengi1, Sean B Connor, Joseph B. Voeglein, Natasha M. Laban, Katayi Mwila-Kazimbaya, Caroline C. Chisenga, John Mwaba, David A. Sack, Subhra Chakraborty

Enterotoxigenic Escherichia Coli (ETEC) is an important cause for diarrheal disease in children and travelers globally. Epidemiological data on the distribution of strains of ETEC and associated colonization factors (CFs) is important for evaluation of candidate vaccines. We used conventional PCR and quantitative PCR to screen for toxins and CFs using DNA extracted from stool samples which tested positive for ETEC using the Luminex GPP panel collected from children presenting with moderate to severe diarrhea at selected health facilities in Lusaka. 49/106 (46.2%) were positive for at least one toxin (i.e. LT/STh/STp), ST was 18 (17%) [STh 16(15%) and STp 2 (~2%)], and LT 16(15%). The most frequent CF detected was CS6 with 6/49 (12.2%), followed by CS2, CS3 and CS7 with 2/49 (4.1%) each. CS6 was common across all toxin combinations (LT only, STh only and a combination of LT/STh) while CS2, CS3, CS7 were identified in both LT and LT/STh strains respectively. The mean age of children with detected toxin or CFs was 15.4 months (95% CI: 12.2, 18.7). Our results offer an insight into relevant CFs in ETEC diarrhea in Zambia and that Luminex™ platform is not as specific as ordinary and quantitative PCR for ETEC detection.