Clinical experience and microbiologic characteristics of invasive Staphylococcus lugdunensis infection in a tertiary center in northern Taiwan

Background/PurposeStaphylococcus lugdunensis is a coagulase-negative staphylococcus that cannot be ignored. This study is a comprehensive analysis of the clinical and microbiological characteristics of S. lugdunensis bacteremia and sterile site infection during hospitalization.MethodsThis retrospective study included 48 patients with invasive S. lugdunensis infection. During the period of March 2002 to July 2012, they had been hospitalized in a tertiary center of northern Taiwan. Demographics, clinical characteristics, and risk factors of mortality were analyzed. All isolates were tested for antimicrobial susceptibility. We identified the staphylococcal cassette chromosome mec (SCCmec) gene for oxacillin nonsusceptible isolates.ResultsThe incidence of S. lugdunensis in coagulase-negative staphylococci bacteremia was 0.87%. Forty-eight patients were enrolled: S. lugdunensis was present in 41 patients with bacteremia, in the ascites of three patients, in the synovial fluid of two patients, in the pleural effusion of one patient, and in the amniotic fluid of one patient. The three most common sources of infection were primary bacteremia (43.8%), catheter-related infection (18.8%), and vascular graft infection (12.5%). All-cause mortality during hospitalization was 20.8% (10/48). All deceased patients were bacteremic. Risk factors associated with in-hospital mortality included a Pittsburgh bacteremia score of 2 or greater, infective endocarditis, and end-stage renal disease. Ten (20.8%) isolates were resistant to oxacillin, and 8 isolates were classified as SCCmec type V.ConclusionThe clinical significance of S. lugdunensis should not be ignored, especially in patients with severe comorbidities. An aggressive search for endocarditis is strongly suggested in S. lugdunensis bacteremic cases.