Determination of drug resistance profiles of lactobacillus species found in cheese and human subjects

DETERMINATION OF DRUG RESISTANCE PROFILES OF LACTOBACILLUS SPECIES FOUND IN CHEESE AND HUMAN SUBJECTS Res. Asist. Bülent GÖGEBAKAN M. Sci. Thesis Gaziantep University Institute of Health Sciences Department of Medical Biology Supervisor: Asist. Prof. Dr. Osman ÇATALOLUK December2003, 65 pages ABSTRACT Resistance profiles of Lactobacillus species which are a member of lactic acid bacteria (LAB) were investigated in 14 mouth, 32 fecal, 36 vaginal samples of human origin (total 82) and 1 raw milk, 15 whey cheese, 50 hand-made cheese, 20 marketed cheese, and 10 yogurt samples of dairy origin (total 111). Strains were cultured in both MRS broth and agar. Gram staining was performed to bacteria grown on agar plates. Four single colonies were picked up from each agar plates. Total DNA isolation was performed to the single colonies. Lactobacillus species were determined by PCR with primers specific to 16S-23S rRNA intergenic sequences (IRS). Samples were found to contain Lactobacillus crispatus (78), L. gasseri (61), L. acidophilus (48), L. plantarum (44), L. rhamnosus (33), L.johnsonii (13), and L. casei (5). Using the same DNA samples erm (ermA, B, C, erm, and ermGT), van (varcAHRSXYZ, vanBXYZ), tetM, and cat-TC gene clusters were searched with specific primers to these genes. In 68 % of the mouth samples, 75 % of the fecal samples, and 80 % of the vaginal samples ermB and/or tetM resistance genes were found to present. However, only 18 % of the samples of dairy origin were found to carry ermB and/or tetM resistance genes. mThese results showed that drug resistance is not a big problem in dairy products. However, drug resistance is a problem to take measures in samples of human origin. Thus, it could be concluded that drug resistance may be obtained via gastrointestinal and vaginal tract not through dairy products. Key words: Lactobacillus, PCR, ermB, van, tetM, and cat-TC resistance, and molecular typing IV