Epidemiological surveillance and risk stratification of diarrhoeagenic bacterial pathogens: a multi-centre hospital study in Lagos, Nigeria

Abstract Background Diarrhoeal diseases remain a major global health concern, particularly in low- and middle-income countries, contributing significantly to morbidity and mortality among children under five. This study investigates the prevalence, demographic distribution, and bacterial pathogens associated with diarrhoeal illness in Lagos, Nigeria. Methods A total of 1,679 stool samples were collected from patients irrespective of their age presenting with diarrhoea across three public hospitals in Lagos State between December 2018 and April 2022. Bacterial isolation was performed using selective enrichment techniques, and identification was confirmed using the Microbact 24E identification system. Statistical analyses assessed the correlation between patient demographics, pathogen distribution, and predictors of positive bacterial cultures. Results The overall prevalence of culture-positive diarrhoea was highest at Massey Street Children’s Hospital (46.1%), followed by Alimosho General Hospital (15.7%) and Lagos State University Teaching Hospital (12.4%). Escherichia coli, including E. coli O157:H7, was the predominant pathogen, especially among children under five. Salmonella spp., Shigella dysenteriae, and Klebsiella spp. were also detected. Males exhibited a significantly higher infection rate (21.9%) than females (18%). Multivariable analysis identified MSCH had significantly higher odds of a positive bacterial culture compared to LASUTH (OR = 6.05; 95% CI: 4.49–8.13; p < 0.001) and male sex (OR = 1.28; 95% CI: 1.00–1.62; p = 0.056) as insignificant independent predictors of positive bacterial cultures, while patients aged 11–40 years had a 50% lower likelihood of positivity compared to children aged 0–5 years (OR = 0.50; 95% CI: 0.40–0.65; p < 0.001). Conclusion This study highlights the substantial burden of bacterial diarrhoea in Lagos, with notable demographic and institutional variability. The findings underscore the need for strengthened diarrhoeal disease surveillance and targeted public health intervention programmes to curb diarrhoeal disease transmission.