VFJ Φ,a New Filamentous Bacteriophage From Vibrio Cholerae

Filamentous phages have important role in Gram-negative bacteria, giving them many pathogenicity and survival related features. For Vibrio cholerae is even more so, important factors including the cholera toxin, are carried on phages. A novel filamentous phage, designated VFJΦ, was isolated from an ampicillin and kanamycin resistant0139serogroup Vibrio cholerae strain ICDC-4470. The genome of VFJΦ was8555nucleotides long, including12predicted ORFs, which were organized in a modular structure. VFJO was found to be a mosaic of two groups of phages of V. cholerae; a large part of the genome was highly similar to that of the fs2phage, and the remaining700bp were homologous to VEJΦ and VCYΦ. This700bp region gave VFJΦ several characteristics that are not found in fs2Φ and other filamentous phages. In its native host ICDC-4470and newly-infected strain N16961, VFJΦ existed as plasmid but did not integrate into the host chromosome. It was found to have a relatively wide host range, but did not infect the classical biotype O1V. cholerae strains. After infection, the host strains exhibited obvious inhibition of both growth and flagellum formation and had obtained low-level ampicillin resistance and-high level kanamycin resistance. The antibiotic resistances were not directly conferred to the hosts by phage encoded genes and not related to penicillinase. VFJ Φ is the only one which is a mosaic of two groups of filamentous phage from vibrio cholerae so far. The discovery of the VFJO updates our understanding of the filamentous phage as well as the understanding of the evolution and classification of V. cholerae filamentous phage, and provides new information about the interaction between phages and their host bacteria. Objective:Antibiotics resistance was investigated in the Vibrio parahaemolyticus isolates from Tongzhou district of Beijing to provide helpful guide for clinical treatment and prevention of food poisoning of V. parahaemolyticus. Methods:A total of60V. parahaemolyticus strains, isolated from Tongzhou district between2009and2011were selected and their MICs of23clinical commonly used antibiotics were tested by the micro-dilution assay. The present of plasmid and integrons that may be relative with drug resistance were also analyzed. Results:The sensitivities of four antibiotics were lower than40%, which are amoxicillin, ampicillin, polymyxin and penicillin. For tobramycin, there are5%intermediate strains. All of strains were sensitive to other18antibiotics. A few of plasmids were presented in the strains including two plasmids bigger than30Kb, and two strains were SXT element positive. Conclusion:The antibiotics resistance of V. parahaemolyticus isolates in Tongzhou district was not serious. Except ampicillin antibiotics and polymyxin, others were effective for treatment of infections of V. parahaemolyticus.