Identification and antibiotic sensitivity profile of potential bacterial toxin producers from some foods sold to students within Enugu state university of science and technology (ESUT) campus

Abstract

Food borne diseases have become major public health burden and bacteria especially the toxin producers have been mostly implicated as among the most common causative agents. Thus, the need to screen and identify most frequent bacteria associated with ready to eat foods consumed within ESUT campus. The food samples were chicken, egg, tomato, vegetable salad and dried fish. A total of 25 samples were collected, with 5 for each sample .They were cultured for bacterial isolation using selective media prior to phenotypic characterization via morphology and biochemical analysis . The predominant isolates were further subjected to genotypic characterization using 16S rRNA sequencing. Each identified isolate of inoculum size of 1.5x 108cfu/ml was exposed in-vitro to analytical Gram+ve and Gram-ve antibiotics by disc diffusion method .The results revealed the presence of Staphylococcus aureus strain OPD001-1 in 5samples, Citrobacter werkmanii strain UMH18 in 3 samples, Salmonella enterica subsp. entericaserovar strain CFSAN027396 in 4 samples, Salmonella enterica subsp. entericaserovar typhimurium in 4 samples and Salmonella enteric strain 2011k-1440 in 4 samples and Salmonella enteric subsp. entericaserovar in 5 samples respectively. Their antibiotic susceptibility pattern differed. Gram positive Staphylococcus aureus was susceptible (>20mm) to 7 test antibiotics (Erythromycin, Levofloxacin, Cephalexin, Ciprofloxacin, Gentamicin, Ofloxacin and Clindamycin ) and resistant (<14mm) to 3 (Cetriaxone, Ampicillin and Cloxacillin). Citrobacter werkmanii and Salmonella enteric subsp. entericaserovar demonstrated similar susceptibility (>20mm) to 7 test Gram-ve antibiotics but resistant to Amoxicillin, Streptomycin and Gentamicin while Salmonella enterica strain 2011k-1440 and Salmonella enteric subsp. entericaserovar typhimurium were resistant (<14mm) to Nitrofurantion , Cetriaxone and Amoxicillin. Although these bacterial isolates can be inhibited by some antibiotics, their implications as potential toxin producers including the heat stable ones pose health problems to food consumers.