Genomic analysis of bacteriophage ϕAB1, a ϕKMV-like virus infecting multidrug-resistant Acinetobacter baumannii.

We present the complete genomic sequence of a lytic bacteriophage ϕAB1 which can infect many clinical isolates of multidrug-resistant Acinetobacter baumannii. The recently isolated bacteriophage displays morphology resembling Podoviridae family. The ϕAB1 genome is a linear double-stranded DNA of 41,526 bp containing 46 possible open reading frames (ORFs). The majority of the predicted structural proteins were identified as part of the phage particle by mass spectrometry analysis. According to the virion morphology, overall genomic structure, and the phylogenetic tree of RNA polymerase, we propose that ϕAB1 is a new member of the ϕKMV-like phages. Additionally, we identified four ORFs encoding putative HNH endonucleases, one of which is presumed to integrate and create a genes-in-pieces DNA polymerase. Also, a potential lysis cassette was identified in the late genome. The lytic power of this bacteriophage combined with its specificity for A. baumannii makes ϕAB1 an attractive agent for therapeutic or disinfection applications.

Chang KC ，Lin NT ，Hu A ，Lin YS ，Chen LK ，Lai MJ ... -  《-》

Bioinformatic analysis of the Acinetobacter baumannii phage AB1 genome.

As one of the pathogens of hospital-acquired infections, Acinetobacter baumannii poses great challenges to the public health. A. baumannii phage could be an effective way to fight multi-resistant A. baumannii. Here, we completed the whole genome sequencing of the complete genome of A. baumannii phage AB1, which consists of 45,159 bp and is a double-stranded DNA molecule with an average GC content of 37.7%. The genome encodes one tRNA gene and 85 open reading frames (ORFs) and the average size of the ORF is 531 bp in length. Among 85 ORFs, only 14 have been identified to share significant sequence similarities to the genes with known functions, while 28 are similar in sequence to the genes with function-unknown genes in the database and 43 ORFs are uniquely present in the phage AB1 genome. Fourteen function-assigned genes with putative functions include five phage structure proteins, an RNA polymerase, a big sub-unit and a small sub-unit of a terminase, a methylase and a recombinase and the proteins involved in DNA replication and so on. Multiple sequence alignment was conducted among those homologous proteins and the phylogenetic trees were reconstructed to analyze the evolutionary courses of these essential genes. From comparative genomics analysis, it turned out clearly that the frame of the phage genome mainly consisted of genes from Xanthomonas phages, Burkholderia ambifaria phages and Enterobacteria phages and while it comprises genes of its host A. baumannii only sporadically. The mosaic feature of the phage genome suggested that the horizontal gene transfer occurred among the phage genomes and between the phages and the host bacterium genomes. Analyzing the genome sequences of the phages should lay sound foundation to investigate how phages adapt to the environment and infect their hosts, and even help to facilitate the development of biological agents to deal with pathogenic bacteria.

Li P ，Chen B ，Song Z ，Song Y ，Yang Y ，Ma P ，Wang H ，Ying J ，Ren P ，Yang L ，Gao G ，Jin S ，Bao Q ，Yang H ... -  《-》

Isolation and characterization of phi AB2: a novel bacteriophage of Acinetobacter baumannii.

Multidrug-resistant strains of Acinetobacter baumannii (MDRAB) are increasingly being reported worldwide. Bacteriophage therapy is a potential alternative treatment for MDR bacterial infections. Although A. baumannii infection has been experimentally treated with phages, no MDRAB-specific phage has been characterized. In this study, 10 phages with differing host ranges and lysis efficacy for MDRAB were isolated; one of these, phi AB2, was further studied. Electron microscopy revealed phi AB2 to have an isometric head (60 nm), a short tail (diameter, 9 nm; length, 11 nm) and a double-stranded DNA genome--which was resistant to digestion with several restriction endonucleases--estimated to be 40 kb by pulsed-field gel electrophoresis. Partial genome sequencing of a 2.1 kb region gave sequences resembling the tubular proteins A and B of Pseudomonas aeruginosa phage LKA1. These data suggest that phi AB2 resembles phi KMV-like phages and is a new member of the Podoviridae family. It exhibited rapid adsorption (>99% adsorbed in 8 min), a short latent period (<10 min) and a large burst size (ca. 200); moreover, it was capable of infecting a wide spectrum of A. baumannii strains, causing virtually complete lysis, indicating that phi AB2 may be a good candidate as a therapeutic/disinfectant agent to control nosocomial infections caused by MDRAB.

Lin NT ，Chiou PY ，Chang KC ，Chen LK ，Lai MJ ... -  《-》

Complete genome sequence of the siphoviral bacteriophage Βϕ-R3177, which lyses an OXA-66-producing carbapenem-resistant Acinetobacter baumannii isolate.

Jeon J ，D'Souza R ，Pinto N ，Ryu CM ，Park JH ，Yong D ，Lee K ... -  《-》

Novel Fri1-like Viruses Infecting Acinetobacter baumannii-vB_AbaP_AS11 and vB_AbaP_AS12-Characterization, Comparative Genomic Analysis, and Host-Recognition Strategy.

Popova AV ，Lavysh DG ，Klimuk EI ，Edelstein MV ，Bogun AG ，Shneider MM ，Goncharov AE ，Leonov SV ，Severinov KV ... -  《Viruses-Basel》