Antibiogram of Bacteria Isolated from Tympanotonus fuscatus Var. Radula (Prosobranchia:Potamididae) Sold in Markets in Nasarawa State, Nigeria

The aim of this study was to determine the antibiogram of bacterial isolates from Tympanotonus fuscatus var. radula sold in markets in Nasarawa State. Nigeria. Samples of Tympanotonus fuscatus var. radula (periwinkles) were bought from soup ingredient sellers at different sale locations in Keffi, Masaka and Orange markets and were analyzed using standard bacteriological methods. The bacterial isolates were identified using morphological, cultural and biochemical techniques. The total bacteria count varied from 1.18–3.20 x 108 CFU/g for the raw samples while the total bacterial count for the boiled samples varied from 0–1.57 x 108 CFU/g. Periwinkle samples with shells from Masaka market had the highest bacterial load with a mean total bacterial count of 2.94 x 10⁸ CFU/g and mean total coliform count of 2.80 x 10⁶ CFU/g. Raw periwinkle samples with shells had a higher bacterial load than samples without shells. There was also a drastic reduction in the bacterial load in the periwinkle samples after boiling under laboratory conditions. The bacteria isolated were Bacillus spp. and Staphylococcus aureus were the Gram-positive bacteria isolated. Enterobacter spp., Escherichia coli, Salmonella spp., Pseudomonas spp., Serratia spp. and Proteus spp. The most frequently occurring gram positive bacteria was Escherichia coli with an isolation frequency of 6(24%), the least frequently occurring was Bacillus spp., 8(32)%. Antibiotic susceptibility test showed that all the gram negative organisms exhibited sensitivity to ciprofloxacin: Escherichia coli (32 mm), Enterobacter spp. (41.5 mm), Proteus spp. (40.0 mm), Salmonella spp. (37.0 mm), Serratia spp. (26.0 mm), Pseudomonas spp. (23.0 mm). All the gram negative organisms showed marked resistance to vancomycin: Escherichia coli (12.0 mm), Enterobacter spp. (10.0 mm), Proteus spp. (11.0 mm), Salmonella spp. (5.0 mm), Serratia spp. (10.0 mm) and Pseudomonas spp. (4.5 mm).