Genomic, Functional, and Evolutionary Insights into a Novel T7-like Phage B1 Infecting Multidrug-Resistant...

Area of Science:

• Microbiology
• Virology
• Genomics

Background:

• Multidrug-resistant (MDR) Enterobacter cloacae poses a significant global health threat.
• There is an urgent need for novel antimicrobial strategies to combat MDR pathogens.

Purpose of the Study:

• To isolate and characterize a lytic phage with activity against MDR Enterobacter cloacae.
• To evaluate the phage's potential for therapeutic applications.

Main Methods:

• Isolation and purification of lytic phage B1 from sewage.
• Morphological characterization using electron microscopy.
• Determination of phage stability under various environmental conditions (temperature, pH).
• Assessment of lytic efficiency, latent period, and burst size.
• Whole-genome sequencing and bioinformatic analysis (including comparative genomics).
• Phylogenetic analysis based on ICTV criteria.

Main Results:

• Phage B1, with an icosahedral head and short tail, demonstrated potent lytic activity against MDR E. cloacae.
• B1 exhibited stability across a wide pH range (5-11) and moderate temperatures (4-37 °C).
• The phage displayed a rapid lytic cycle (latent period <10 min) and high burst size (~150 PFU/cell).
• Genome sequencing revealed a 40,163 bp dsDNA genome with 52 ORFs.
• Phylogenetic analysis placed B1 as a new species within the Kayfunavirus genus (Autographiviridae family), related to T7-like phages.
• B1 lacks lysogeny and virulence genes.

Conclusions:

• Phage B1 is a novel T7-like phage with significant lytic efficacy against MDR Enterobacter cloacae.
• Its robust characteristics and absence of virulence factors make it a strong candidate for phage therapy.
• This study expands the understanding of T7-like phage diversity and therapeutic potential.