Virulence of Staphylococcus Lugdunensis in Severe Infections (VISLISI)

The main objective is to identify new virulence factors produced by Staphylococcus lugdunensis that can be associated with clinical sign of severe infections and identified symptoms. The methodological approach is based on the comparison between the production of toxins by a given S. lugdunensis isolate classified in patients groups according to the infection clinically defined. Each group will be compared to the presence or not of studied virulence factors. Clinical features associated with toxin activity are not known for S. lugdunensis. This comparative approach is based on the hypotheses that drove to the definition of patient groups and their clinical criteria. However, in the absence of the evident correlation between production of toxins and kind of infection, the statistical evaluation will be completed by a multi-varied analysis. This approach has not been choosen first because of the multiple parameters that undergo during infection that may reveal relationships without true correlation. About the number of included patients in each defined group, if one of them does not reach the expected count, we still might extend inclusions to 3-6 months more. The presence of severe infections without usually defined risk is intriguing. For these last patients, we have planned, after their individual consent to achieve an exome sequencing. The obtained data will be compared to available resources for the human genome. By filtering data through usual protocols, we hope to able to focus onto few genes that evoke specific sensitivity to infections, e.g. severe endocarditis due to S. lugdunensis without defined risk.

Several groups will be compared considering the presence/absence of virulence factors: Bacteriemic VS non bacteriemic, Deep infection VS Skin/mucosal infection, Foreign body infection VS not, Presence of abscess VS not, Sepsis VS no sepsis, Septic embolism VS not, Portal of entry or not The following virulence factors will be searched for: TSST-1, enterotoxins, leukotoxins, epidermolysins, beta-hemolysins, SCIN-CHIPS, Sbi, Efb, SdrE

Characteristics of infection: comorbidities (Charlson score) - history of the disease - clinical, cytological , immunological, inflammatory and organ functions parameters - results of additional tests conducted under their care - response to treatment - morbidity and mortality

Inclusion Criteria: Age 18 or more Signed informed consent form Proved infection by Staphylococcus lugdunensis: bacteremia, urine tract infection, endocarditis, bone and joint infections, skin and soft tissue infection, deep infection. Exclusion Criteria: Age under 18 Pregnancy or breastfeeding Contamination by Staphylococcus lugdunensis