Genomic Characterization of the Novel Aeromonas hydrophila Phage Ahp1 Suggests the Derivation of a New Subgroup from phiKMV-Like Family.

Jian-Bin Wang,Shu-Fen Weng,Yi-Hsiung Tseng,Nien-Tsung Lin,Carmen San Martin

doi:10.1371/journal.pone.0162060

Jian-Bin Wang, Shu-Fen Weng + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0162060

Copy DOI

Journal: PloS one	Publication Date: Sep 7, 2016
Citations: 21	License type: CC BY 4.0

Affiliation: Tzu Chi University, National Chung Hsing University

Abstract

Aeromonas hydrophila is an opportunistic pathogenic bacterium causing diseases in human and fish. The emergence of multidrug-resistant A. hydrophila isolates has been increasing in recent years. In this study, we have isolated a novel virulent podophage of A. hydrophila, designated as Ahp1, from waste water. Ahp1 has a rapid adsorption (96% adsorbed in 2 min), a latent period of 15 min, and a burst size of 112 PFU per infected cell. At least eighteen Ahp1 virion proteins were visualized in SDS-polyacrylamide gel electrophoresis, with a 36-kDa protein being the predicted major capsid protein. Genome analysis of Ahp1 revealed a linear doubled-stranded DNA genome of 42,167 bp with a G + C content of 58.8%. The genome encodes 46 putative open reading frames, 5 putative phage promoters, and 3 transcriptional terminators. Based on high degrees of similarity in overall genome organization and among most of the corresponding ORFs, as well as phylogenetic relatedness among their DNAP, RNAP and major capsid proteins, we propose a new subgroup, designated Ahp1-like subgroup. This subgroup contains Ahp1 and members previously belonging to phiKMV-like subgroup, phiAS7, phi80-18, GAP227, phiR8-01, and ISAO8. Since Ahp1 has a narrow host range, for effective phage therapy, different phages are needed for preparation of cocktails that are capable of killing the heterogeneous A. hydrophila strains.

Highlights

Aeromonas hydrophila, a gram-negative, rod-shaped, non-spore-forming and facultatively anaerobic bacterium, is widely distributed in aquatic environments, drinking water, chlorinated water supply, and a wide range of food [1,2,3]
It has been demonstrated that third- and forth-generation cephalosporins and fluoroquinolones were effective against over 80% of the infections caused by Aeromonas species in Taiwan [8, 11, 12], the increasing rates of antibiotic resistances have raised the concern in treatment of A. hydrophila infections [13,14,15,16]
Results showed that infecting a culture of A. hydrophila ATCC 7966 (200 ml of Luria Bertani (LB) medium in a 500 ml flask) at exponential phase (0.8 unit of optical density at 600 nm (OD600)) with an multiplicity of infection (MOI) of 0.0001 caused a complete lysis of the culture within

Summary

Introduction

A gram-negative, rod-shaped, non-spore-forming and facultatively anaerobic bacterium, is widely distributed in aquatic environments, drinking water, chlorinated water supply, and a wide range of food [1,2,3]. It causes various human infections such as bacteremia, pneumonia, endocarditis, empyema, arthritis, biliary tract infections, peritonitis, PLOS ONE | DOI:10.1371/journal.pone.0162060. Genomic Characterization of the Novel Aeromonas hydrophila Phage Ahp and skin and soft-tissue infections [4,5,6,7,8] This species causes diseases in fish, including Aeromonas septicemia, red sore disease and ulcerative infections mainly affecting carp and catfish [9]. It has been demonstrated that third- and forth-generation cephalosporins and fluoroquinolones were effective against over 80% of the infections caused by Aeromonas species in Taiwan [8, 11, 12], the increasing rates of antibiotic resistances have raised the concern in treatment of A. hydrophila infections [13,14,15,16]

Methods

Results

Conclusion