Antimicrobial Resistance of Tomato-Spoiling Microorganisms from Ajegunle Market, Oyo Town, Oyo State, Nigeria

Abstract

Pathogenic bacteria and fungi associated with tomato spoilage have the tendency of harbouring antimicrobial resistance genes that can pose significant health threats to consumers, hence the need to ascertain their antibiotic sensitivity. Five spoilt tomato samples were purchased from five different tomato sellers in Ajegunle market, Oyo Town, Oyo State, Nigeria. Isolation was carried out using the pour plate method. The antibiogram of selected antibiotics and antifungal drugs against the bacteria and fungi isolates was determined using the diffusion disk technique. Colony count for bacteria ranged from 1.0 x 10³ – 6.3 x 10³ CFU/mL on Nutrient agar and 1.0 x 10³ – 9.6 x 10³ CFU/mL on MacConkey agar while the fungal count ranged from 2.2 x 10⁵ – 5.1 x 10⁵ CFU/mL on potato dextrose agar. The bacteria identified were Staphylococcus aureus, Aeromonas veronii, Bacillus cereus, B. brevis, B. pumilus, B. licheniformis, B. subtilis, Corynebacterium xerosis, Corynebacterium kutscheri and Lactobacillus casei with B. licheniformis being the most prevalent. Fungal isolates identified were: Saccharomyces cerevisiae, Rhizopus spp. and Fusarium spp. with Saccharomyces cerevisiae being the most prevalent. Most of the Gram-positive bacteria were resistant to Azithromycin (87.5%), Gentamycin (90.7%), Ofloxacin (93.7%) and Erythromycin (93.7%) while Aeromonas veronii was resistant to Gentamycin, Levofloxacin, Ofloxacin and Nitrofurantoin at 50% respectively, while Fusarium species showed resistance against Griseofulvin. The bacterial isolates' multi-antibiotic resistance (MAR) index ranged from 0.3 to 0.8. The resistance of the isolated microorganisms to commercial drugs could be risky to public health.