Characterizing the Biology of Lytic Bacteriophage vB_EaeM_φEap-3 Infecting Multidrug-Resistant Enterobacter aerogenes.

Jiangtao Zhao,Weishi Lin,Ruo Feng,Xiao Chen,Changyu Tian,Huan Li,Jing Yuan,Aimin Jiang,Xiao Wei,Zhe Yin,Lingfei Hu,Xiangna Zhao,Zheng Zhang

doi:10.3389/fmicb.2019.00420

Abstract

Carbapenem-resistant Enterobacter aerogenes strains are a major clinical problem because of the lack of effective alternative antibiotics. However, viruses that lyze bacteria, called bacteriophages, have potential therapeutic applications in the control of antibiotic-resistant bacteria. In the present study, a lytic bacteriophage specific for E. aerogenes isolates, designated vB_EaeM_φEap-3, was characterized. Based on transmission electron microscopy analysis, phage vB_EaeM_φEap-3 was classified as a member of the family Myoviridae (order, Caudovirales). Host range determination revealed that vB_EaeM_φEap-3 lyzed 18 of the 28 E. aerogenes strains tested, while a one-step growth curve showed a short latent period and a moderate burst size. The stability of vB_EaeM_φEap-3 at various temperatures and pH levels was also examined. Genomic sequencing and bioinformatics analysis revealed that vB_EaeM_φEap-3 has a 175,814-bp double-stranded DNA genome that does not contain any genes considered undesirable for the development of therapeutics (e.g., antibiotic resistance genes, toxin-encoding genes, integrase). The phage genome contained 278 putative protein-coding genes and one tRNA gene, tRNA-Met (AUG). Phylogenetic analysis based on large terminase subunit and major capsid protein sequences suggested that vB_EaeM_φEap-3 belongs to novel genus “Kp15 virus” within the T4-like virus subfamily. Based on host range, genomic, and physiological parameters, we propose that phage vB_EaeM_φEap-3 is a suitable candidate for phage therapy applications.

Highlights

Over the last three decades, Enterobacter aerogenes has increasingly been recognized as an important opportunistic and multidrug-resistant bacterial pathogen associated with nosocomial infections (Davin-Regli and Pages, 2015)
We focused on E. aerogenes phage vB_EaeM_φEap-3, a T4-like bacteriophage belonging to the genus “Kp15 virus” within the family Myoviridae
Enterobacter aerogenes clinical strain 3-SP is a generous gift from Dr Dongsheng Zhou, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China, which is isolated from a human case of pneumonia at a Chinese teaching hospital (Chen et al, 2015)

Summary

INTRODUCTION

Over the last three decades, Enterobacter aerogenes has increasingly been recognized as an important opportunistic and multidrug-resistant bacterial pathogen associated with nosocomial infections (Davin-Regli and Pages, 2015). Characterization of Bacteriophage vB_EaeM_φEap-3 first-line drugs for the treatment of severe nosocomial infections caused by multidrug-resistant Enterobacteriaceae (Qin et al, 2014). Clinicians should be alert to carbapenem-resistant E. aerogenes infection to ensure the timely initiation of appropriate therapy (Kuai et al, 2014; Tuon et al, 2015). There are only four reported fully-sequenced E. aerogenes phages: F20 (JN672684; Mishra et al, 2012), vB_EaeM_φEap-2 (NC_028695; Li et al, 2016), vB_EaeM_φEap-1 (NC_028772), and UZ1 (unclassified; Verthe et al, 2004). We focused on E. aerogenes phage vB_EaeM_φEap-3, a T4-like bacteriophage belonging to the genus “Kp15 virus” within the family Myoviridae

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION