# Novel Bacillus-Infecting Phage Bquatquinnuvirus eskimopiis (Strains B450T and B450C), Founder of a New Genus, and the Properties of Its Endolysin

## TL;DR

Scientists discovered two new phages that infect Bacillus bacteria and a powerful enzyme from one of them that could help fight drug-resistant bacteria.

## Contribution

A new genus of Bacillus-infecting phage is proposed, along with characterization of a broad-spectrum endolysin for combating drug-resistant bacteria.

## Key findings

- Phages B450T and B450C lyse 38% of Bacillus cereus strains, with B450C showing enhanced activity due to repressor mutations.
- Endolysin PlyC19 lyses 56% of tested strains, including Priestia flexa, with optimal activity at pH 9.0 and thermal stability up to 40 °C.
- PlyC19's structure includes an Amidase_2 domain and dual SH3 domains, enabling targeted peptidoglycan hydrolysis.

## Abstract

This study characterizes two novel Bacillus phages, B450T and B450C, isolated from Bacillus thuringiensis VKM B-450 via mitomycin C induction, along with their endolysin, PlyC19. Both phages, siphoviruses with 41,205 bp genomes, lysed 38% of the tested Bacillus cereus sensu lato strains, with B450C showing enhanced lytic activity due to mutations in the repressor protein. PlyC19 lysed 56% of the strains tested, including Priestia flexa, demonstrating broader efficacy. Its Amidase_2 domain and dual SH3 cell wall-binding domains enable targeted peptidoglycan hydrolysis, with optimal activity at pH 9.0 and thermal stability up to 40 °C. We propose the taxonomic designation Bquatquinnuvirus eskimopiis for these phages, with B450T and B450C representing distinct strains, based on genomic divergence in the repressor protein’s HTH_Xre domain, consistent with their turbid and clear plaque morphologies, respectively. PlyC19′s broad specificity underscores its potential as an enzybiotic against multidrug-resistant Bacillus cereus group strains in food safety and medicine.