The identification of lactic acid bacteria isolated in mother's milk with 16S rRNA sequence analysis and determination of antibiotic resistance and antibacterial activities

In this study, a total of 48 suspected lactic acid bacteria were isolated from the sample of 30 mother's milk from University of Health Sciences Van Education and Research Hospital Dairy Child Service. The 16S rRNA PCR analysis of the suspected isolates revealed that 14 isolates gave a band at 1465 bp. Sequence analysis of PCR products prepared with universal 16S rRNA primer of these isolates revealed that the isolates showed high similarity to following species Lactobacillus (5), Pediococcus (5) and Enterococcus (1) when they were BLAST. Plasmid counts isolated from lactic acid bacteria strains range from 1 to 5. When the plasmids were evaluated for their size, it was determined that the largest plasmid was above about 10,000 bp. LAB strains showed the highest sensitivity to chloramphenicol (100%) and the lowest sensitivity to rifampisin (36.4%) in the study to determine resistance to antibiotics. The isolates showed the highest moderate sensitivity to rifampisin (54.6%) while the lowest moderate sensitivity to penicillin G (18.2%). The strains showed the highest resistance to vancomycin, gentamicin, nalidixic acid and polymyxin antibiotics (100%) while the lowest resistance to rifampisin (9.0%). While 9 isolates were resistant against penicillin, the remaining 2 isolates (6 and 7) showed moderate susceptibility. When the antimicrobial effects of 11 isolated lactic acid bacteria on other bacteria were examined, it was observed that they had no effect on test bacteria.