Abstract:

Background: Diarrhea due to Escherichia coli serotype O157:H7 is one of the leading causes of morbidity and mortality globally among enteropathogens. Previous study conducted in Mwanza Tanzania on diarrhea among under five children was based on detection of Shiga Toxin Producing Escherichia coli (STEC). This study aim to add more information (in addition of under five children with diarrhea) by including domestic and their surrounding environmental premises to determine the prevalence and drug susceptibility pattern of STEC serotype O157:H7 and STEC non O157:H7 isolates in Mwanza and Shinyanga, Tanzania.

Methods: A cross sectional study was conducted involving under five children with diarrhea, domestic animals and environmental specimens between May to July 2018 and 2019 in Mwanza and Shinyanga, Tanzania. Stool samples from children with diarrhea, recto-fecal samples from domestic animals and selected environmental samples (such as juices, salad, and water) were collected and cultured on MacConkey agar and CHROMO agar to identify Escherichia coli and STEC, respectively. Then, all STEC isolates were cultured in Sorbitol MacConkey agar to identify STEC serotype O157:H7. Demographic and clinical information were collected using a standard tool and STATA software version 13.0 used for data analysis.


Results: Out of 355 stool samples of under five children, 290 (86.7%) had positive culture results, where by 220 (62%) samples were positive for E. coli. Out of 220 E. coli, 45 (20.5%) were STEC positive and out 45 positive STEC, 5 (11.1%) were O157H7. Out of 285 animal specimens, 217 (76.1%) had positive culture results, where by 204 (71.6%) were positive for E. coli. Out of 204 E. coli, 52 (25.5%) were STEC positive and out of 52 STEC positive, 7 (13.5%) were O157H7. Out of 142 environmental specimens collected, 56 (39.4%) had positive culture results, where by 15 (10.6%) were positive for E. coli. Out of 15 E. coli, 5 (33.3%) were STEC positive and out of 5 STEC strains, 3 (60%) were O157H7. Children under five years of age residing in urban areas had higher STEC (28.4%) than those residing in the rural areas (17.0%), although the association was not statistically significant (p-value=0.058). STEC was significantly associated with domestic animals residing in Sengerema (20.5%) and Shinyanga (34.6%) compared to Mwanza (7.0%), P-value <0.001. STEC was also associated with chicken (22.0%) and pigs (33.3%) compared to other domestic animals (p-value=0.013)

Conclusions: The proportions of STEC among E. coli strains in three interfaces is high but the proportions of E. coli O157:H7 is low. Of note, STEC strains were more associated children in urban areas, and also in chicken and pigs.

Significance: This study added more information on the STEC and STEC O157:H7 as potential causes of diarrhea among children under five years of ages, and also evaluated the potential source of these pathogens among domestic animals and environmental premises. These is turn will help in the institution of specific preventive measures using One Health Approach.