Antibiotic Susceptibility and Plasmid Profile of Lactobacillus Species Isolated from Yoghurt and Cheese retailed in Ado Ekiti. Ekiti state, Nigeria

Lactobacillus species are involved in the production of cheese and yoghurt and are consumed normally along with the food. However, they have the potential of harboring antibiotic resistant genes which can lead to ineffective treatment of infections when such antibiotics are prescribed. The aim of this study was to determine the prevalence of antibiotic susceptibility of Lactobacillus isolated from yoghurt and cheese retailed in Ado- Ekiti, and the role of plasmids when resistance to multiple antibiotics is detected. Commercially prepared yoghurt (three) and cheese (three) retailed in Ado- Ekiti were analyzed in this study. Isolation of Lactobacillus sp. was carried out on De Man Rogosa Sharpe (MRS) agar using pour plate method. Microbial characterization was carried out using cultural and biochemical test as described by Bergey’s manual of Systematic Bacteriology. Susceptibility to 8 antibiotics was done using disc diffusion method. Plasmid detection for ten isolates with multiple antibiotic resistances was determined by the alkaline lysis method. Plasmid curing was also done using acridine orange. Four Lactobacillus spp was isolated, namely: L. brevis (6), L. fermentum (8), L. plantarum (3), and L. casei (6). Average resistance to the 8 antibiotics among all species of Lactobacillus isolated from both cheese and yoghurt ranged between 64% - 100%. Resistance to ≥ 2 classes of antibiotics was observed in 12 out 23 isolates of Lactobacillus. Percentage resistance after plasmid curing was ranged from 0% - 63%. This study shows that plasmid is one of the major factors recognized for the rapid spread of antimicrobial resistance among Lactobacillus spp.