Heterogeneity of Molecular Characteristics among Staphylococcus argenteus Clinical Isolates (ST2250, ST2793, ST1223, and ST2198) in Northern Taiwan.

Jia-Chuan Hsu,Po-Ren Hsueh,Tsai-Wen Wan,Xiao-Mei Wang,Lee-Jene Teng,Chiau-Jing Jung,Tai-Fen Lee,Hao Lee,Yu-Tzu Lin

doi:10.3390/microorganisms8081157

Abstract

Staphylococcus argenteus is an emerging pathogen that is recognized as non-pigmented Staphylococcus aureus. However, the molecular characteristics of S. argenteus and its virulence factors have not been well studied. The present study analyzed 96 isolates of S. argenteus recovered from blood. Identification of S. argenteus was based on results of MALDI-TOF MS and lacking crtM gene. All 96 isolates were methicillin-susceptible. Multilocus sequence typing (MLST) revealed four sequence types: ST2250 (n = 72), ST2793 (n = 12), ST1223 (n = 10), and ST2198 (n = 2). All 72 ST2250 isolates harbored CRISPR loci with polymorphism of direct repeats and spacers, but no other STs carried CRISPR loci. To date, ST2793 isolates have rarely been reported in other countries. Collagen-binding adhesin gene (cna) and staphylococcal enterotoxin type C (sec) were detected in 12 (100%) and 8 (67%) ST2793 isolates, respectively. ST1223 has been reported as food poisoning pathogens, and enterotoxin gene clusters (egc) were detected in all 10 isolates, while seb gene was detected in three isolates. Two ST2198 isolates carried bone sialoprotein-binding protein gene (bbp), belonging to agr type IV. Our focus on the heterogeneity of molecular characterization in four ST types of S. argenteus revealed that S. argenteus had been isolated as early as 2000. Each ST type of S. argenteus harbors particular genetic markers that may contribute to their virulence.

Highlights

Staphylococcus argenteus is an emerging pathogen that has been recognized as non-pigmentedStaphylococcus aureus displaying white colonies on chocolate agar plates owing to lack of the crtOPQMN gene operon required for staphyloxanthin pigment production. [1,2]
All 96 isolates were recovered from blood cultures and first identified as S. aureus by Vitek2 but displayed white colonies and lacked the crtM gene, pigment production-associated genes, and whole crt operon
All 96 isolates were identified as S. argenteus by MALDI-TOF

Summary

Introduction

Staphylococcus argenteus is an emerging pathogen that has been recognized as non-pigmentedStaphylococcus aureus displaying white colonies on chocolate agar plates owing to lack of the crtOPQMN gene operon required for staphyloxanthin pigment production. [1,2]. Staphylococcus argenteus is an emerging pathogen that has been recognized as non-pigmented. Staphylococcus aureus displaying white colonies on chocolate agar plates owing to lack of the crtOPQMN gene operon required for staphyloxanthin pigment production. S. argenteus was proposed in 2015, and it is a divergent lineage branching from S. aureus, with approximately 10% nucleotides divergence or 87% average nucleotides identity (ANI) [2]. S. argenteus is a Gram-positive, catalase-positive, and coagulase positive cocci and demonstrates β-hemolysis on blood agar [2]. The type strain of S. argenteus MSHR1132T (= DSM 28299T ) was isolated from the blood culture of an indigenous patient in 2006 in Darwin, Northern Territory, Australia, and it belongs to ST1850, methicillin-resistant and initially recognized as clonal complex 75 (CC75) [2]

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