Three Novel Bacteriophages, J5a, F16Ba, and z1a, Specific for Bacillus anthracis, Define a New Clade of Historical Wbeta Phage Relatives

Aleksandra Nakonieczna,Magdalena Kwiatek,Paweł Rutyna,Małgorzata Łobocka,Magdalena Fedorowicz,Lidia Mizak

doi:10.3390/v14020213

Abstract

Bacillus anthracis is a potent biowarfare agent, able to be highly lethal. The bacteria dwell in the soil of certain regions, as natural flora. Bacteriophages or their lytic enzymes, endolysins, may be an alternative for antibiotics and other antibacterials to fight this pathogen in infections and to minimize environmental contamination with anthrax endospores. Upon screening environmental samples from various regions in Poland, we isolated three new siphophages, J5a, F16Ba, and z1a, specific for B. anthracis. They represent new species related to historical anthrax phages Gamma, Cherry, and Fah, and to phage Wbeta of Wbetavirus genus. We show that the new phages and their closest relatives, phages Tavor_SA, Negev_SA, and Carmel_SA, form a separate clade of the Wbetavirus genus, designated as J5a clade. The most distinctive feature of J5a clade phages is their cell lysis module. While in the historical phages it encodes a canonical endolysin and a class III holin, in J5a clade phages it encodes an endolysin with a signal peptide and two putative holins. We present the basic characteristic of the isolated phages. Their comparative genomic analysis indicates that they encode two receptor-binding proteins, of which one may bind a sugar moiety of B. anthracis cell surface.

Highlights

Often fatal zoonotic disease caused by B. anthracis, a spore-forming rod typically found in soil within the environment of herbivores [1]
The host range of the selected phages was investigated with the use of 51 bacterial strains, including four virulent B. anthracis strains
We present in this work the genomic and basic biological characteristics of three newly isolated B. anthracis phages—J5a, F16Ba, and z1a

Summary

Introduction

Often fatal zoonotic disease caused by B. anthracis, a spore-forming rod typically found in soil within the environment of herbivores (i.e., sheep, cattle, and goats) [1]. Spores are extremely resistant to harsh environmental conditions, and for this reason, they can survive in the soil for years and infect grazing animals [2]. One may suspect that B. anthracis strains with naturally or artificially developed antibiotic resistance can be potentially used in a bioterrorist attack [5]. It is of public interest to develop novel, rapid antibacterial agents against B. anthracis, with different modes of action than those of commonly used antibiotics. Phages and their lytic enzymes, endolysins (or lysins), may become such agents due to their high specificity and activity against antibiotic-resistant bacteria

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Results

Conclusion