A Novel Gene, fudoh, in the SCCmec Region Suppresses the Colony Spreading Ability and Virulence of Staphylococcus aureus

Chikara Kaito,Makiko Nagata,Hiroki Yamaguchi,Yosuke Omae,Kazuhisa Sekimizu,Teruyo Ito,Yasuhiko Matsumoto,Taiji Aoto,Keiichi Hiramatsu,Christophe Herman

doi:10.1371/journal.pone.0003921

Chikara Kaito, Makiko Nagata + Show 8 more

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https://doi.org/10.1371/journal.pone.0003921

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Abstract

Staphylococcus aureus colonies can spread on soft agar plates. We compared colony spreading of clinically isolated methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). All MSSA strains showed colony spreading, but most MRSA strains (73%) carrying SCCmec type-II showed little colony spreading. Deletion of the entire SCCmec type-II region from these MRSA strains restored colony spreading. Introduction of a novel gene, fudoh, carried by SCCmec type-II into Newman strain suppressed colony spreading. MRSA strains with high spreading ability (27%) had no fudoh or a point-mutated fudoh that did not suppress colony spreading. The fudoh-transformed Newman strain had decreased exotoxin production and attenuated virulence in mice. Most community-acquired MRSA strains carried SCCmec type-IV, which does not include fudoh, and showed high colony spreading ability. These findings suggest that fudoh in the SCCmec type-II region suppresses colony spreading and exotoxin production, and is involved in S. aureus pathogenesis.

Highlights

Staphylococcus aureus is a pathogenic bacterium that causes various diseases in humans
We examined the colony spreading of 10 methicillin-sensitive S. aureus (MSSA) strains and 40 methicillin-resistant S. aureus (MRSA) strains on soft agar plates
We examined the reason for the decreased colony spreading of most of the MRSA strains, and the high colony spreading of some MRSA strains and all MSSA strains

Summary

Introduction

Staphylococcus aureus is a pathogenic bacterium that causes various diseases in humans. We previously reported that S. aureus has the ability to spread on soft agar surfaces, which we termed ‘‘colony spreading’’ [11]. Because bacterial translocation, such as flagella-driven swimming, is considered a bacterial virulence mechanism [12,13,14], the spreading ability of S. aureus is suspected to have a role in its virulence. We examined the spreading ability of clinically isolated MSSA, MRSA, and CA-MRSA strains, and report a novel gene that affects both the colony spreading ability and virulence of S. aureus

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