Prevalence and Antimicrobial Resistance Patterns of Escherichia coli O157:H7, Salmonella, and Shigella Species from Stool Samples of Patients with Diarrhea at Benjamin Mkapa Hospital

Background: Enterobacteriaceae is among the large group of gram-negative rod bacteria in which it comprises Escherichia coli, Salmonella, Shigella, and many other species whose natural habitat is the intestinal tract of humans and animals. Diarrheal diseases are a major problem worldwide caused by bacterial pathogens particularly in developing countries. A previous study reported a prevalence of 9.30% Extended Spectrum Beta Lactamases (ESBLs) producing Enterohemorrhagic Escherichia coli O157:H7 that revealed a high (100%) resistance to gentamicin, tetracycline, trimethoprim/sulphamethoxazole, and amoxicillin/ clavulanic acid.

Methods: A laboratory-based cross-sectional study was conducted at BMH. A convenient sampling method was used to enroll 308 patients with diarrhea in the study after consent for 12 months. Stool samples were collected into an acceptable clean sterile stool container and transported to Microbiology department for investigation. Analysis of data was performed using Statistical Package for Social Sciences (SPSS) version 17.0.

Results: Out of 308 participants, 61.0% (188) were female whereas 39.0% (120) were male. The age group of between 18 to 45 years had a larger number of participants recruited in study 257 (83.4%) and less number 4 (1.2%) in the age group above 60 years old. About 5.2 (16/308) percent of stool samples processed were positive with pathogenic bacteria whereas 94.8 (292/308) percent were negative (no pathogenic bacteria isolated) growth. The study presented two pathogenic bacteria species named E. coli strain O157:H7 and Salmonella typhi that were isolated from stool samples of patients with diarrhea and who attended the hospital for treatment. No any shigella species was isolated in the study. The prevalence of S. typhi was 3.2% (10/308) whereas E. coli strain O157:H7 was 1.9% (6/308) out of 308 stool samples processed. The in vitro drug resistance patterns of Ampicillin were observed to be high 9 (90%) followed by Amoxicillin/Clavulanate and tetracycline of which both had 6 (60%) resistance to S. typhi.

Conclusion: The study is currently insisting laboratory practitioners carry out an investigation of Escherichia coli strain O157:H7 as a routine test in parallel with other enteric pathogens.