Prevalence, determinants, and antimicrobial resistance of enteric bacterial infections among under-five children in Nairobi County.

Diarrhoeal disease remains a major cause of morbidity and mortality among children under five, especially in low- and middle-income countries where poor water, sanitation, and hygiene (WASH) infrastructure exacerbates its impact. This cross-sectional study examined the prevalence, antimicrobial resistance (AMR) patterns, and risk factors for enteric bacterial infections in 216 children aged 0–60 months in Nairobi County, Kenya. Stool analysis yielded 204 bacterial isolates, predominantly Escherichia coli (36.3%), Shigella sonnei (11.8%), Enterobacter cloacae (9.8%), and Aeromonas hydrophila (8.8%). The highest prevalence occurred in children aged 48–60 months (23.5%), with females accounting for 59.3% of isolates. Antimicrobial susceptibility testing revealed high E. coli susceptibility to meropenem (100.0%), gentamicin (96.6%), and ciprofloxacin (96.6%), but substantial resistance to ampicillin (78.0%) and nitrofurantoin (30.5%). S. sonnei showed complete resistance to ampicillin and high resistance to nitrofurantoin (66.7%). Resistance to nitrofurantoin was also frequent in A. hydrophila (94.4%) and Enterobacter spp. Socio-demographic assessment indicated that most caregivers had tertiary education (50.9%) and low to moderate incomes; half had piped water access, and 44.4% used shared sanitation, yet poor household hygiene was observed in 51.9%. Clinically, diarrhoea was often accompanied by abdominal pain (93.5%), fever (55.6%), and dehydration (46.3%). Oral rehydration salts and zinc were commonly used, while 44% of children had taken antibiotics in the month prior to sampling. The findings reveal a high burden of bacterial diarrhoea and AMR in this setting, underscoring the urgent need for improved WASH infrastructure, antibiotic stewardship, and targeted public health interventions.