کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6136276 | 1593712 | 2014 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Role of the two-component regulatory system arlRS in ica operon and aap positive but non-biofilm-forming Staphylococcus epidermidis isolates from hospitalized patients Role of the two-component regulatory system arlRS in ica operon and aap positive but non-biofilm-forming Staphylococcus epidermidis isolates from hospitalized patients](/preview/png/6136276.png)
- Fifteen ica+aap+/BFâ clinical isolates of Staphylococcus epidermidis was found.
- The ica+aap+/BFâ isolates had low icaA transcriptional levels, poor PIA production, and weak Aap expression.
- The arlRS transcriptional level was low in all ica+aap+/BFâ isolates.
- The phenotype of an arlRS knockout mutant was similar to that of the ica+aap+/BFâ isolates.
The ica operon and aap gene are important factors for Staphylococcus epidermidis biofilm formation. However, we found 15 out of 101 S. epidermidis strains isolated from patients had both the ica operon and the aap gene in the genome but could not form biofilms (ica+aap+/BFâ isolates). Compared with standard strain RP62A, the 15 ica+aap+/BFâ isolates had similar growth curves and initial attachment abilities, but had much lower apparent transcription levels of the icaA gene and significantly less production of polysaccharide intercellular adhesion (PIA). Furthermore, the expression of accumulation-associated protein in ica+aap+/BFâ isolates was much weaker than in RP62A. The mRNA levels of icaADBC transcription-related regulatory genes, including icaR, sarA, rsbU, srrA, arlRS and luxS, were measured in the 15 ica+aap+/BFâ clinical isolates. The mRNA levels of arlR and rsbU in all of the ica+aap+/BFâ isolates were lower than in RP62A at 4 h. At 10 h, 14/15 of the isolates showed lower mRNA levels of arlR and rsbU than shown by RP62A. However, expression of sarA, luxS, srrA and icaR varied in different ica+aap+/BFâ isolates.To further investigate the role of arlRS in biofilm formation, we analyzed icaA, sarA and rsbU transcription, PIA synthesis, Aap expression and biofilm formation in an arlRS deletion mutant of S. epidermidis strain 1457 and all were much less than in the wild type strain. This is consistent with the hypothesis that ArlRS may play an important role in regulating biofilm formation by the ica+aap+/BFâS. epidermidis clinical isolates and operate via both ica-dependent and Aap-dependent pathways.
Journal: Microbial Pathogenesis - Volume 76, November 2014, Pages 89-98