DIVERSITY, ANTIBIOGRAM AND PLASMID PROFILE OF MICROBIAL CONTAMINANTS OF SOME SELECTED VEGETABLES SOLD IN BAYELSA NIGERIA

Abstract

This study identified 12 microorganisms, including eight bacteria and four fungi associated with different vegetables; cabbage (Brassica oleracea), ugu leaf (Telfairia occidentalis), scent leaf (Ocimum gratissimum), okra (Abelmoschus esculentus), waterleaf (Talinum fruticosum), uziza leaf (Piper guineense), and bitter leaf (Vernonia amygdalina) sold in Otuoke market located in southern Nigeria. Cultural methods were used to quantitatively and qualitatively elucidate fungi and bacteria contaminants in the samples. The average bacteria concentration across all the vegetables was 3.88 X 10⁹cfu/g. Abelmoschus esculentus had the highest bacterial concentration of 9.03 (10⁹) cfu/g, while Brassica oleracea has the least bacterial load of 1.67 (10⁹) cfu/g. The coliform count ranged from 0.5 to 2.63 (10⁹) cfu/g for Vernonia amygdalina and Ocimum gratissimum respectively. Mean coliform count was 8.43(10⁹) cfu/g. The fungi count varied from 0.5 to 1.5 (10³) cfu/g for Ocimum gratissimum and Vernonia amygdalina respectively. Biochemical and morphological characterization identified Enterobacter sp., Escherichia coli, Klebsiella sp., Salmonella Sp., Serratia marcescens, Micrococcus sp., Proteus mirabilis and Staphylococcus sp. as key bacterial contaminants of the vegetables. Fungi species isolated from these vegetables include Aspergillus niger, Alternaria sp., Rhizopus sp. and Fusarium sp. The antibiotic susceptibility testing revealed that al the organism isolated were resistant to two or more antibiotics, including a 100% resistance to the penicillin family of antibiotics. Furthermore, all the isolates contained plasmids with a range of 100-200kbp except Salmonella sp., and the fungi; Rhizopus, Fusarium and Alternaria.