Analysis of Antibiotic Resistance and Antimicrobial Effects of Enterococcus faecium and Lactococcus lactis Isolated from Khorramabad Traditional Cheeses

Document Type : Original Article


1 Department of Genetics, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran

2 Department of Microbiology, Science and Research Branch, Islamic Azad University, Arak, Iran

3 Department of Nutrition, Faculty of Health and Nutrition, Lorestan University of Medical Sciences, Khorramabad, Iran


Enterococcus and lactococcus are Gram-positive cocci that often occur in pairs (diplococci) or short chains, and are difficult to differentiate from streptococci on physical characteristics alone. Enterococcus faecium because have concern antibiotic resistant, consider difficult as probiotic. The results of an assay show that a probiotic E. faecium strain might be a potential recipient of Vancomycin resistance genes. For analysis of this concept, 13 samples of traditional cheeses were collected from different areas in Khorramabad city and identified with using phenotypic methods, and then the bacteriocin was extract from indentified bacteria. Agar diffusion method was used to assay the antimicrobial activities of bacteriocin produced by isolated bacteria against Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, E. coli, Bacillus cereus and Bacillus subtilis. On the other hand, antibiotic resistance of these bacteria was test using antibiogram method. The results showed that some of bacteria such as P.  aeruginosa, S. aureus, and E. coli are intermediately resistance while P. vulgaris was completely sensitive and B. cereus and B. subtilis were resistant. Also, the Enterococcus faecium was resistant to kanamycin and trimethoprim antibiotics and intermediatly to clindamycin and tetracycline, and sensitive to amoxicillin and erythromycin. Lactococcus lactis was sensitive to trimethoprin, amoxicillin, tetracycline, and erythromycin while was resistant to kanamycin and clindamycin. In this study both bacteria enterococcus faecium and lactococcus lactis had an inhibitory effect on pathogenic bacteria and, these bacteria also have an appropriate antibiotic resistance to most antibiotics.