Limitations in the use of PSM gamma, agr, RNAIII, and biofilm formation as biomarkers to define invasive Staphylococcus epidermidis from chronic biomedical device-associated infections

作者：Harris Llinos G^*; Dudley Ed; Rohde Holger; Frommelt Lars; Siemssen Nicolaus; Wilkinson Thomas S; Mack Dietrich

来源：International Journal of Medical Microbiology, 2017, 307(7): 382-387.

DOI：10.1016/j.ijmm.2017.08.003

• Staphylococcus epidennidis agr
• Quorum sensing
• Infection
• Phenol soluble modulins
• Biomedical devices
• Biofilm formation

Staphylococcus epidermidis is a common cause of biomedical device-associated infections. Agr is the major quorum sensing system in staphylococci and regulates virulence factors. Four agr-specificity groups exist in S. epidermidis, and chronic S. epidermidis infections are hypothesised to select for agr-negative phenotypes. Therefore, we investigated S. epidermidis strains from prosthetic joint- and catheter-associated infections to establish i) whether an infection selects for an agr-negative phenotype; ii) the importance of PSM gamma and iii) if the agr-specificity group is infection dependent. S. epidermidis nasal isolates from healthy volunteers were used as controls. The distribution of agr-specificity groups was significantly different between infection and control episodes, but did not distinguish between the infection types. PSM gamma secretion was used to determine agr-activity and HPLC analysis showed that 44% of prosthetic and 32% of catheter-associated episodes produced no PSM gamma in comparison to 8% of the control strains. However, PSM gamma expression did not always correlate with RNAIII up regulation, indicating that PSM gamma synthesis is likely influenced by additional post-transcriptional control. The data suggests chronic S. epidermidis infections favour agr-specificity group 1 but the results suggest that they do not select for an agr-negative phenotype. Further studies are required to explore the mechanisms underlying the selection and survival of these S. epidermidis phenotypes isolated from biomedical device-associated infections.

• 出版日期2017-10
• 单位河北医科大学