Assessment of the plasmid transferring ability of Lactobacillus rhamnosus to pathogen

Abstract

Assessment of the plasmid transferring ability of Lactobacillus rhamnosus to pathogen is important in the drug resistant prevention when using of Lactobacillus to treat infection in animal and human. To obtain the aim of the study, Lactobacillus rhamnosus plasmid was isolated to make sure plasmid exist in this strain. Then, the antimicrobial susceptibility in Lactobacillus rhamnosus was done to know whether this strain can resist which antimicrobial agents to contribute to antibiotic resistant marker in plasmid. Therefore, 9 antibiotics including amoxicillin, ampicillin, cephalexin, chloramphenicol, clindamycin, erythromycin, penicillin, sulbactam, tetracycline were used to test the antimicrobial susceptibility in Lactobacillus rhamnosus. As a result, Lactobacillus rhamnosus resisted cephalexin. To study the Plasmid transferring ability from Lactbacillus rhamnosus to pathogen, cephalexin susceptibility was tested in (Candida albicans, Micrococcus luteus, Pseudomonas aeruginosa, Salmonella typhi). Consequently, Salmonella typhi was sensitive to cephalexin. Although Lactobacillus rhamnosus could treat Salmonella typhi, but when the amount of Lactobacillus was not enough to treat Salmonella typhi definitely, there might be a plasmid gene transfer. Therefore, the conjugation between Lactobacillus rhamnosus and Salmonella typhi was optimized. In the ratio of Lactobacillus (104 cfu/ml) and Salmonella typhi (3x104 cfu/ml), the conjugation of these bacteria occurred. The conjugated Salmonella typhi was test for cephalexin resistance and the plasmid appearance in this strain. As a result, conjugated Salmonella typhi became to resist to cephalexin. Plasmid isolation in conjugated Salmonella typhi and polymerase chain reaction, using primers of cephalexin resistant gene were done to identify the plasmid of Lactobacillus rhamnosus in Salmonella typhi. In conclusion, there was the plasmid transferring from Lactobacillus rhamnosus to Salmonella. Key words: Lactobacillus rhamnosus , Salmonella typhi , cephalexin, plasmid transferring.