Capsular Polysaccharide Is a Receptor of a Clostridium perfringens Bacteriophage CPS1.

Eunsu Ha,Sangryeol Ryu,Jihwan Chun,Minsik Kim

doi:10.3390/v11111002

Eunsu Ha, Sangryeol Ryu + Show 2 more

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https://doi.org/10.3390/v11111002

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Journal: Viruses	Publication Date: Oct 31, 2019
Citations: 16	License type: CC BY 4.0

Affiliation: Seoul National University, Yonsei University

Abstract

Clostridium perfringens is a Gram-positive, anaerobic, and spore forming bacterium that is widely distributed in the environment and one of the most common causes of foodborne illnesses. Bacteriophages are regarded as one of the most promising alternatives to antibiotics in controlling antibiotic-resistant pathogenic bacteria. Here we isolated a virulent C. perfringens phage, CPS1, and analysis of its whole genome and morphology revealed a small genome (19 kbps) and a short noncontractile tail, suggesting that CPS1 can be classified as a member of Picovirinae, a subfamily of Podoviridae. To determine the host receptor of CPS1, the EZ-Tn5 random transposon mutant library of C. perfringens ATCC 13124 was constructed and screened for resistance to CPS1 infection. Analysis of the CPS1-resistant mutants revealed that the CPF_0486 was disrupted by Tn5. The CPF_0486 was annotated as galE, a gene encoding UDP-glucose 4-epimerase (GalE). However, biochemical analyses demonstrated that the encoded protein possessed dual activities of GalE and UDP-N-acetylglucosamine 4-epimerase (Gne). We found that the CPF_0486::Tn5 mutant produced a reduced amount of capsular polysaccharides (CPS) compared with the wild type. We also discovered that glucosamine and galactosamine could competitively inhibit host adsorption of CPS1. These results suggest that CPS acts as a receptor for this phage.

Highlights

Clostridium perfringens is a Gram-positive, spore-forming, anaerobic bacterium that is widely distributed in nature [1]
We discovered that glucosamine and galactosamine could competitively inhibit host adsorption of CPS1
Viruses 2019, 11, 1002 phages utilizing different receptors, this phenomenon can delay the development of resistant bacteria, since it is much more difficult for bacteria to mutate a number of different receptors [11,12]. These findings suggest that identification of the phage receptor is essential to improve the efficiency of phage therapy [13,14]

Summary

Introduction

Clostridium perfringens is a Gram-positive, spore-forming, anaerobic bacterium that is widely distributed in nature [1]. C. perfringens spores can persist in the environment, and the bacteria cause infectious diseases, such as gas gangrene and necrotic enteritis, in humans and animals. Enterotoxigenic strains of C. perfringens can cause food poisoning [2,3]. Bacteriophages (or phages) are defined as viruses that infect and kill bacteria. Interest about phage therapy has recently been revived because of the worldwide problem of antibiotic-resistant bacteria [5]. The host range of phage is narrow, so phages can be used to destroy target bacteria without disrupting the natural microflora. A phage cocktail composed of multiple phages is used to increase the phage host range [6,7] and to delay the appearance of phage-resistant bacteria [8]

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Conclusion