Isolations And Identifications Of The Bifidobacterium And Lactobacillus From Cows And Their Resistance Characteristics To Given Antibacterial Drugs

To screen the beneficial Bifidobacterium and Lactobacillus with high performance and drug resistance, widen the range and mode of its utilization, the isolation, identification, bionomics and resisitance of Bifidobacterium and Lactobacillus strains isolated from feces of cows in Huhhot were studied .The 49 strains of Bifitobacteria and Lactobacilli from the fresh feces of calf never used antimicrobials were isolated and its drug resistance research were carried out. The morphological, physiological, biochemical characteristics and identification of multiple PCR and 16SrRNA sequence analysis of 7 strains with higher drug resistance of 49 strains were studied, the results showed that 3 strains belong to Lactobacillus plantarum, 2 strains belong to Bifidobacterium choleyium and 2 strains belonged to Bifidobacterium catemulatum.The K-B method was adopted to determine the drug resistance of these 49 strains, the results showed that these strains had a certain drug resistance to 12 kinds of antimicrobials. Among the total, the strains of drug resistance of 49 strains were 49 to metronidazole, 45 to aminoglycosides, 10 to tetracycline, 10 to chloramphenicol, 19 to Chloramphenicol, and about 37 to fluoroquinolones.The cylinder plate method was adopted to study the resistance of 7 strains; the results showed that these strains had a resistance to 12 kinds of antimicrobials. Among the total, 3 trains of Lactobacillus plantarum were resistant to all antimicrobial except 1 strain was sensitive to tetracycline and Levofloxacin, 2 strains of Bifidobacterium choleyium were resistant to all antimicrobial except 1 strain was sensitive to chlormycetin, 2 strains of Bifidobacterium catemulatum were sensitive to tetracycline, and resistant to else antimicrobial except 1 strain was sensitive to ampicillin. These test organism were higher resistant to aminoglycosides and arilin. The resistance degree of these strains were different for several antibacterials because of the kinds of strains. The R-plasmid of 7 strains were detected by agar gel electrophoresis, their active efflux system were determined by fluorospectrophotometry, and their QRDR sequence of gyrA gene were detected by PCR technique and gene sequencing, the results showed that there is active efflux system in these strains but no R-plasmid in these strains, and the gyrA gene had happened mutationConculsions: 49 strains of Bifidobacterium and Lactobacillus were resistant to 12 kinds of antimicrobials at different degree, among the total, the resistance to arilin reached 100%, the resistance to aminoglycosides reached 87.8%, the resistance to tetracyclines, chlormycetin and erythromycin were low (20.4%-38.8%), and the resistance to fluoroquinolones were more than 70%. 7 strains of Bifidobacterium and Lactobacillus hade higher multidrug resistance. Among the total, had higher resistance to aminoglycosides and arilin. The drug resistant mechanism of test organism to fluoroquinolones had no relationship to mediation of plasmid, but had relationship to their active efflux system and the mutation of gyrA gene.