RESUMEN
Bacteriophages are considered as promising biological agents for the control of infectious diseases. Sequencing of their genomes can ascertain the absence of antibiotic resistance, toxin or virulence genes. The anti-O157â:âH7 coliphage, PhaxI, was isolated from a sewage sample in Iran. Morphological studies by transmission electron microscopy showed that it has an icosahedral capsid of 85-86 nm and a contractile tail of 115×15 nm. PhaxI contains dsDNA composed of 156â628 nt with a G+C content of 44.5 mol% that encodes 209 putative proteins. In MS analysis of phage particles, 92 structural proteins were identified. PhaxI lyses Escherichia coli O157â:âH7 in Luria-Bertani medium and milk, has an eclipse period of 20 min and a latent period of 40 min, and has a burst size of about 420 particles per cell. PhaxI is a member of the genus 'Viunalikevirus' of the family Myoviridae and is specific for E. coli O157â:âH7.
Asunto(s)
Colifagos/genética , ADN Viral/química , ADN Viral/genética , Escherichia coli O157/virología , Genoma Viral , Myoviridae/genética , Composición de Base , Colifagos/química , Colifagos/aislamiento & purificación , Colifagos/ultraestructura , Irán , Espectrometría de Masas , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Myoviridae/química , Myoviridae/aislamiento & purificación , Myoviridae/ultraestructura , Sistemas de Lectura Abierta , Análisis de Secuencia de ADN , Aguas del Alcantarillado/virología , Virión/química , Virión/ultraestructuraRESUMEN
BACKGROUND AND OBJECTIVES: Multi-drug-resistant Enterobacter aerogenes is associated with various infectious diseases that cannot be easily treated by antibiotics. However, bacteriophages have potential therapeutic applications in the control of multi-drug-resistant bacteria. In this study, we aimed to isolate and characterize of a lytic bacteriophage that can lyse specifically the multi-drug-resistant (MDR) E. aerogenes. MATERIALS AND METHODS: Lytic bacteriophage was isolated from Qaem hospital wastewater and characterized morphologically and genetically. Next-generation sequencing was used to complete genome analysis of the isolated bacteriophage. RESULTS: Based on the transmission electron microscopy feature, the isolated bacteriophage (vB-Ea-5) belongs to the family Myoviridae. vB-Ea-5 had a latent period of 25 minutes, a burst size of 13 PFU/ml, and a burst time of 40 min. Genome sequencing revealed that vB-Ea-5 has a 135324 bp genome with 41.41% GC content. The vB-Ea-5 genome codes 212 ORFs 90 of which were categorized into several functional classes such as DNA replication and modification, transcriptional regulation, packaging, structural proteins, and a host lysis protein (Holin). No antibiotic resistance and toxin genes were detected in the genome. SDS-PAGE of vB-Ea-5 proteins exhibited three major and four minor bands with a molecular weight ranging from 18 to 50 kD. CONCLUSION: Our study suggests vB-Ea-5 as a potential candidate for phage therapy against MDR E. aerogenes infections.