Abscesses and wound infections due to Staphylococcus lugdunensis: report of 16 cases

Staphylococcus lugdunensis has emerged as a major human pathogen, capable of causing significant infections at many sites. It should never be dismissed as a contaminant without careful review. We report 16 cases of wound infections and skin and soft tissue abscesses caused by S. lugdunensis during a period of 3.5 years (January 2008-June 2011). These cases were isolated from clinical specimens in a tertiary hospital (250 beds) in Athens, Greece.

The identification of S. lugdunensis was based on Gram staining, catalase and coagulase test results, and 26 biochemical reactions that were included in the database of the MicroScan Walkaway 96 commercial system. The susceptibility pattern was performed with the same commercial system according to CLSI recommendations.

Twenty-five isolates were classified as S. lugdunensis, of which 16 were considered to be clinically significant. The age distribution of the patients ranged from 29 to 65 years. Patient outcome after treatment was good with no long-term sequel. All isolated S. lugdunensis were methicillin sensitive (cefoxitin screen negative), while five isolates were β-lactamase producers. The isolates were susceptible to most of the antibiotics tested except for a few cases that were resistant to erythromycin, tetracycline, and clindamycin.

Coagulase-negative staphylococci isolated from traumatic and surgical wound infections should be identified by microbiological laboratories to the species level, and susceptibility testing should be performed on these isolates so as not to underrate the virulence of staphylococci resembling S. aureus.