One Health Approach to Biofilm Formation and Extended-Spectrum Beta-Lactamase Mediated Antibiotic Resistance in Escherichia coli O157:H7 in Arusha Region, Tanzania

Abstract

Background: The One Health concept recognizes the interconnectedness of human, animal and environmental health in the emergence and spread of antimicrobial resistance. Zoonotic pathogens such as Escherichia coli O157:H7 can circulate between humans, livestock and environmental reservoirs. Its ability to form biofilms enhances persistence and survival, while the production of extended-spectrum beta-lactamases (ESBLs) contributes to resistance and limits treatment options.
Objective: To investigate the biofilm formation, extended-spectrum beta-lactamase production, and antibiotic resistance profiles of Escherichia coli O157:H7 isolates from humans, cattle and hospital sewage systems in the Arusha Region and to assess their interrelated associations.
Methods: A cross-sectional study was conducted in the Arusha Region, Tanzania. A total of 371 samples were involved. Shiga toxin producing E coli were isolated from clinical human cases, fresh feces from cattle and hospital sewage. Isolated bacteria were identified using standard microbiological techniques and antimicrobial susceptibility was evaluated according to current Clinical and Laboratory Standards Institute (CLSI) guidelines. Ability to form biofilms was assessed using the crystal violet microtiter plate assay. Phenotypic ESBL production was detected using the combined disk diffusion test (CDDT). Data analysis used IBM SPSS Statistics for Windows version 25.0 (IBM Corp, Armonk, NY, USA).
Results: Escherichia coli O157:H7 was detected across sectors with higher prevalence in cattle (n=12, 16.7%) compared to humans (n=7, 3.5%) and hospital sewage (n=2, 2.0%). Overall, 15(71.4%) isolates were multidrug resistance. High resistance was observed to ampicillin (n=17, 81.0%), tetracycline (n=15, 71.4%), trimethoprim-sulfamethoxazole (n=14, 66.6%), and ceftazidime (n=11, 52.4%). Production of ESBL occurred in 4(19.0%) isolates. Biofilm formation was observed in 8(38.1%) isolates and was significantly associated with tetracycline resistance (χ²=8.00, P=.018).
Conclusion: The coexistence of biofilm formation and ESBL production in Escherichia coli O157:H7 highlights the importance of a One Health approach in antimicrobial resistance monitoring. Integrated surveillance, antimicrobial stewardship and improved environmental and veterinary controls are essential to reduce zoonotic transmission and mitigate antimicrobial resistance.