title: Lytic myophage Abp53 encodes several proteins similar to those encoded by host Acinetobacter baumannii and phage phiKO2.
abstract: Acinetobacter baumannii is an important Gram-negative opportunistic pathogen causing nosocomial infections. The emergence of multiple-drug-resistant A. baumannii isolates has increased in recent years. Directed toward phage therapy, a lytic phage of A. baumannii, designated Abp53, was isolated from a sputum sample in this study. Abp53 has an isometric head and a contractile tail with tail fibers (belonging to Myoviridae), a latent period of about 10 min, and a burst size of approximately 150 PFU per infected cell. Abp53 could completely lyse 27% of the A. baumannii isolates tested, which were all multiple drug resistant, but not other bacteria. Mg(2+) enhanced the adsorption and productivity of, and host lysis by, Abp53. Twenty Abp53 virion proteins were visualized in SDS-polyacrylamide gel electrophoresis, with a 47-kDa protein being the predicted major capsid protein. Abp53 has a double-stranded DNA genome of 95 kb. Sequence analyses of a 10-kb region revealed 8 open reading frames. Five of the encoded proteins, including 3 tail components and 2 hypothetical proteins, were similar to proteins encoded by A. baumannii strain ACICU. ORF1176 (one of the tail components, 1,176 amino acids [aa]), which is also similar to tail protein gp21 of Klebsiella phage phiKO2, contained repeated domains similar to those within the ACICU_02717 protein of A. baumannii ACICU and gp21. These findings suggest a common ancestry and horizontal gene transfer during evolution. As phages can expand the host range by domain duplication in tail fiber proteins, repeated domains in ORF1176 might have a similar significance in Abp53.
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Chia-Ni
authors.initials: CN
authors.lastname: Lee
authors.forename: Tsai-Tien
authors.initials: TT
authors.lastname: Tseng
authors.forename: Juey-Wen
authors.initials: JW
authors.lastname: Lin
authors.forename: Yung-Chieh
authors.initials: YC
authors.lastname: Fu
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Weng
authors.forename: Yi-Hsiung
authors.initials: YH
authors.lastname: Tseng
mesh_terms: D040981:Acinetobacter baumannii / Q000235:genetics / Q000821:virology*; D001433:Bacteriolysis; D001435:Bacteriophages / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification / Q000648:ultrastructure; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007709:Klebsiella / Q000821:virology; D008274:Magnesium / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017900:Myoviridae / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification / Q000648:ultrastructure; D016366:Open Reading Frames; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013183:Sputum / Q000821:virology; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D014771:Virion / Q000648:ultrastructure; D053585:Virus Attachment / Q000187:drug effects
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins; D008274:Magnesium