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Changes in the agrLocus Affect Enteritis Caused by Methicillin-Resistant Staphylococcus aureus

Changes in the agrLocus Affect Enteritis Caused by Methicillin-Resistant Staphylococcus aureus

Authors :
Sugiyama, Yoichi
Okii, Kazuya
Murakami, Yoshiaki
Yokoyama, Takashi
Takesue, Yoshio
Ohge, Hiroki
Sueda, Taijiro
Hiyama, Eiso
Source :
Journal of Clinical Microbiology; May 2009, Vol. 47 Issue: 5 p1528-1535, 8p
Publication Year :
2009

Abstract

ABSTRACTWe studied the characteristics of methicillin (meticillin)-resistant Staphylococcus aureus(MRSA) strains that caused enteritis. In a previous report, we demonstrated that both phenotypic and genotypic changes were associated with MRSA enteritis; and we hypothesized that the accessory gene regulator (agr), which is a global regulator of staphylococcal virulence and upregulates several exoproteins, is the key factor associated with the development of MRSA enteritis. In this study, we examined 12 MRSA isolates associated with enteritis from stool samples and 17 MRSA isolates not associated with enteritis that had the following characteristics: the strains associated with enteritis had the same genotype (genotype A), as detected by pulsed-field gel electrophoresis, or the strains were isolated from stools. The differences between strains that caused enteritis and those that did not cause enteritis strains were examined by quantitative reverse transcription-PCR to assess RNAII, agrA, RNAIII, and tstexpression and by sequencing of the agrlocus. The levels of expression of agrA, RNAIII, and tstwere higher by the MRSA isolates associated with enteritis than by the MRSA isolates not associated with enteritis, whether or not they were of the same genotype. The levels of expression of RNAII by almost all the clinical isolates were similar. Sequencing of the agrlocus showed that all MRSA isolates that caused enteritis have agrmutations, whereas the MRSA isolates that did not cause enteritis, with three exceptions, did not. Many of the isolates associated with enteritis had the same mutation, especially at the C-terminal end of agrA. These results suggest a trend in which mutations in the agrlocus modify the expression of agrAand RNAIII and the production of toxin, all of which may increase the virulence and influence the occurrence of MRSA enteritis.

Details

Language :
English
ISSN :
00951137 and 1098660X
Volume :
47
Issue :
5
Database :
Supplemental Index
Journal :
Journal of Clinical Microbiology
Publication Type :
Periodical
Accession number :
ejs57785997
Full Text :
https://doi.org/10.1128/JCM.01497-08