Prevalence of Coliforms and Their Multidrug-Resistant Strains in Soil Amended with Poultry Manure and in the Leaves of Fluted Pumpkin during Harvest and in Markets

The increase in antibiotic-resistant bacteria on food and vegetables has raised growing global concerns regarding food safety, particularly because the consumption of vegetables represents a direct exposure pathway for humans to soil bacteria. This research aimed to evaluate how poultry manured-soil and fluted pumpkins serve as vectors and reservoirs for coliforms and their multidrug-resistant strains. The study was conducted during the 2024 growing season at two fluted pumpkin farms and two markets in Benin City, Edo State, Nigeria. Coliforms were isolated using the spread plate technique. The isolates were identified using standard phenotypic methods and 16S rRNA gene sequencing. The Kirby-Bauer disk diffusion method was employed to assess the susceptibility of the isolates to antibiotics from seven distinct classes. Isolates exhibiting resistance to antibiotics from at least three antibiotic classes were classified as multidrug-resistant. Klebsiella. pneumoniae, Escherichia coli, Proteus vulgaris, and Enterobacter cloacae were detected in all analyzed samples of fluted pumpkin leaves and soil, while Citrobacter freundii was exclusively found in market samples. Coliforms showed strong resistance to amoxicillin and cefotaxime, and moderate resistance to other antibiotics. Multidrug-resistant coliforms were identified in both soils and leaves, with highest multiple antibiotics resistance (MAR) indices in farm soils. The lowest MAR indices were in fluted pumpkin leaves from New-Benin and Oba Markets. The research concluded on the importance of continuous monitoring of antibiotic resistance patterns in coliforms and their multidrug-resistant strains to ensure food safety, while recommending appropriate decontamination of fluted pumpkins or other agricultural produce before consumption.