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Distribution of sasX, pvl, and qacA/B genes in epidemic methicillin-resistant Staphylococcus aureus strains isolated from East China

Authors Kong H, Fang L, Jiang R, Tong J

Received 6 October 2017

Accepted for publication 28 November 2017

Published 9 January 2018 Volume 2018:11 Pages 55—59


Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Colin Mak

Peer reviewer comments 2

Editor who approved publication: Dr Joachim Wink

Haishen Kong,1,2 Lingmei Fang,3 Rujin Jiang,4 Jixiang Tong2

1State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; 2Key Laboratory of Clinical In Vitro Diagnostic Techniques of Zhejiang Province, Department of Laboratory Medicine, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; 3Clinical Laboratory, Chunan First People’s Hospital, Zhejiang Province People’s Hospital Chunan Branch, Hangzhou, China; 4Clinical Laboratory, Yuhang Hospital of Traditional Chinese Medicine, Hangzhou, China

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen. Various virulence and antiseptic-resistant factors increase the pathogenicity of MRSA strains and allow for increased infection rates.
Purpose: The purpose of this study was to investigate the prevalence and distribution of virulence-associated and antiseptic-resistant genes from epidemic MRSA strains isolated from East China.
Methods: A newly designed multiplex PCR assay was used to assess whether the virulence-associated genes sasX and pvl and the chlorhexidine tolerance gene qacA/B were present in 189 clinical isolates of MRSA. Multilocus sequence typing (MLST) and Staphylococcal protein A (spa) typing of these isolates were also performed. The frequency of these genes in isolates with epidemic sequence types (STs) was investigated.
Results: Twenty STs and 36 spa types with five epidemic clones (ST5-t311, ST59-t437, ST5-t002, ST239-t030, and ST239-t037) were identified. The prevalence of sasX, pvl, and qacA/B in all isolates was 5.8%, 10.1%, and 20.1%, respectively. The prevalences of these genes in isolates with ST5, ST59, ST239, and other ST genetic backgrounds were all significantly different (P<0.001). Isolates that had the highest frequency of sasX, pvl, or qacA/B were ST239 (33.3%), ST59 (28.9%), and ST5 (34.1%), respectively. The gene distribution pattern from all of the isolates showed that sasXpvlqacA/B+, sasXpvl+qacA/B–, and sasX+pvlqacA/B– were closely associated with epidemic clones ST5-t311, ST59-t437, and ST239-t037, respectively.
Conclusion: There are significant differences in the prevalence of virulence-associated and antiseptic-resistant genes in epidemic MRSA strains. Using this information, more effective control and prevention strategies for nosocomial MRSA infections can be developed.

MRSA, MLST, virulence genes, sasX, pvl, qacA/B, multiplex PCR

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