Antibiotic resistance pattern of bacteria isolated from spent engine oil contaminated soil

Spent engine oil contaminated soil not only harbors bacteria resistant to heavy metals but also to antibiotics. This study investigated the antibiotic resistant profile of bacterial isolates from spent engine oil contaminated soil. Two soil samples one each was collected from 10 years old mechanic workshop and pristine environment. Bacteria were isolated using pour plate method. The isolates were identified based on their physiological and morphological characteristics using standard microbiological techniques. Antibiogram studies were carried out by disc diffusion method and results interpreted based on the CLSI guidelines. The isolates were identified as members of eleven genera (Bacillus, Clostridium, Pseudomonas, Rhodococcus, Klebsiella, Escherichia, Providencia, Arthrobacter, Corynebacterium, Serretia and Proteus). Results obtained revealed that all the bacterial isolates obtained from the contaminated soil exhibited antibiotics resistance, these bacterial isolates were highly resistant to cefoxatime (82.4 %) and ceftriaxone (82.4 %). Furthermore, the pristine soil isolates were highly resistant to cefoxatime (88.9 %) and ceftriaxone (88.9 %) and ceftazidime (88.9 %) these are all members of the beta-lactam class cephalosporins. The presence of antibiotics resistant bacteria in spent engine oil contaminated soil as seen in this study shows that it can be a medium of antibiotics resistance spread. Thus, stringent measures on the disposal of spent engine oil should be enforced.