The indiscriminate use of antibiotics by individuals and in food production industry account for spread of plasmid-mediated antibiotic resistance in edible fruits and vegetable pathogens. This study determines isolation and characterization of bacteria, antibiotic susceptibility, plasmid isolation and curing of bacteria from fruits and vegetables in Abeokuta. A total of forty (40) samples of ready to eat Apple, Cucumber, Carrot, Watermelon and Pineapple were screened for total bacterial counts using standard bacteriological methods. Mean total aerobic bacterial counts were between 3.5 x104 and 8.5 x104 CFU/g and total coliform 3.0 x104 to 6.9x104 CFU/g. Isolates were Staphylococcus aureus (15.3%), Escherichia coli (12.5%), Bacillus subtilis (12.5%), Pseudomonas fluorescens (8.3%), Pseudomonas aeruginosa (8.3%), Salmonella sp.(6.9%), Staphylococcus saprophyticus (5.6%), Pseudomonas protegens (5.6%) , Enterobacter sp.(5.6%), Alcaligens faecalis(5.6%), Achromobacter xylosoxidans (5.6%), Proteus vulgaris (4.2%) and Listeria sp.(4.2%). Each of the fruits and vegetables were treated with (acetic acid) vinegar of different concentrations and time. The effect of vinegar concentration (0.5-5%) and exposure time (0-15 min) on the microbial load of fruits and vegetables were assessed and statistically analyzed.. Apples treated with 0.5%, 1.5%, 2.5% and 5.0% of vinegar at 0.0minutes, 5.0mins, 10.0 mins and 15.0 mins had microbial load decreased considerably with p≤ 0.040, p≤0.031, p≤ 0.020 and p≤ 0.014 respectively. The other fruits and vegetables had similar results of vinegar treatment. Antimicrobial susceptibility of the bacterial isolates was done using disc diffusion method on Mueller-Hinton agar with Augmentin, Tetracycline, Ciprofloxacin, Gentamicin, Pefloxacin, Amoxacillin, Erythromycin, Sulphamethoxazole trimethoprim. Thirteen of 72 isolates (18.1%) were multidrug resistant and these were subjected to plasmid curing using sodium dodecyl sulfate (SDS and Tween80). Alcaligens faecalis, Achromobacter xylosoxidans and Pseudomonas protegens remained resistant to Pefloxacin, Amoxacillin, Tetracycline, Sulphamethoxazoletrimethoprim and Augmentin, suggesting that their bacterial resistance is not plasmid mediated. Transmission of non-plasmid mediated antibiotic resistance could be of public health importance in human consumption of edible fruits and vegetables.
Keywords: Fruits and Vegetables., Bacteria., Plasmid Curing., Antibiotic resistance.