Staphylococcus lugdunensis, a rare cause of severe infections such as native valve endocarditis, often causes superficial skin infections similar to Staphylococcus aureus infections. We initiated a study to optimize the identification methods in the routine laboratory, followed by a population-based epidemiologic analysis of patients infected with S. lugdunensis in Viborg County, Denmark. Recognition of a characteristic Eikenella corrodens-like odor on Columbia sheep blood agar combined with colony pleomorphism and prominent ␤-hemolysis after 2 days of incubation, confirmed by API-ID-32 Staph, led to an 11-fold increase in the detection of S. lugdunensis. By these methods we found 491 S. lugdunensis infections in 4 years, corresponding to an incidence of 53 per 100,000 per year, an increase from 5 infections per 100,000 inhabitants in the preceding years. Seventy-five percent of the cases were found in general practice; these were dominated by skin abscesses (36%), wound infections (25%), and paronychias (13%). Fifty-six percent of the infections occurred below the waist, and toes were the most frequently infected site (21%). Only 3% of the patients suffered from severe invasive infections. The median age was 52 years, and the male/female ratio was 0.69. Our study shows that S. lugdunensis is a common cause of skin and soft-tissue infections (SSTI) and is probably underrated by many laboratories. S. lugdunensis should be accepted as a significant pathogen in SSTI and should be looked for in all routine bacteriological examinations, and clinicians should be acquainted with the name and the pathology of the bacterium.Staphylococcus lugdunensis, one of the coagulase-negative staphylococci (CoNS), was first described by Freney et al. 20 years ago (8). It causes severe infections similar to Staphylococcus aureus infections, especially acute endocarditis in prosthetic and native valves (14,24,29,30,36). Other infections such as osteomyelitis (17, 23), peritonitis (28), intravascular catheter infections (5, 32), prosthetic joint infections (26), and urinary tract infections have also been reported (10). S. lugdunensis has been reported as an important cause also of skin and soft tissue infections (SSTI), primarily in the groin (1, 39) and mammae (13,22,25,37,41).S. lugdunensis is part of the normal human skin flora and commonly colonizes the perineal region (1, 37, 39); however, carriage rates of different CoNS are not comprehensively accounted for, and only a few have looked for S. lugdunensis carriage (13, 16, 39).Our study was undertaken after two serious cases of S. lugdunensis infection, a fatal case of endocarditis with protracted bacterial identification but correct antibiotic treatment and a case of late-diagnosed osteomyelitis, which prompted an optimization of our routine microbiological methods for identification of S. lugdunensis. This subsequently increased the number of S. lugdunensis isolates significantly, especially in samples from patients in general practice, and encouraged us to conduct a prospectiv...

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From January 1st 2011 through June 30th 2011, 116 nonreplicate, noncystic fibrosis-related Pseudomonas aeruginosa isolates with reduced carbapenem susceptibility were collected from 12 out of 13 Danish departments of clinical microbiology. The presence of acquired β-lactamases was assessed with combination tablet-diffusion methodology and polymerase chain reaction. In addition, antimicrobial susceptibility testing, an efflux pump inhibitor assay, and pulsed-field gel electrophoresis (PFGE) were performed. Isolates producing acquired β-lactamases were further investigated by serotyping and multi locus sequence typing. Eight isolates produced the metallo-β-lactamase (MBL) VIM-2, and one isolate produced OXA-10 and VEB-1-like extended-spectrum beta-lactamase (ESBL). Phenotypic indications of derepressed AmpC and efflux pump were seen in 56 and 43 isolates, respectively. Overall, the results indicate that mutational factors related to permeability--often combined with derepressed, chromosomal AmpC--is the main factor behind carbapenem nonsusceptibility in Danish P. aeruginosa isolates. The ESBL producer and all the VIM producers belonged to international clones. PFGE revealed that most of the isolates were unrelated, but clonal spread was seen; the 116 isolates distributed in 97 PFGE types, with the largest cluster consisting of 4 isolates (including three isolates from the same hospital with 100% similarity). Thirty-two isolates were pair-wise related, while the remaining isolates were clonally unrelated, as were all nine ESBL/MBL producers.