A total of 212 coagulase-negative Staphylococcus strains recovered prospectively during 119 surgeries for proven or suspected bone and joint infection (BJI) were identified by sodA sequencing. These strains were identified as 151 Staphylococcus epidermidis isolates, 15 S. warneri isolates, 14 S. capitis isolates, 9 S. hominis isolates, 6 S. lugdunensis isolates, 5 S. haemolyticus isolates, 4 S. caprae isolates, 4 S. pasteuri isolates, 3 S. simulans isolates, and 1 S. cohnii isolate. Only S. epidermidis, S. lugdunensis, S. capitis, and S. caprae were found to be infecting organisms and were involved, respectively, in 35 (81.4%), 3 (7.0%), 3 (7.0%), and 2 (4.6%) cases of BJI.Coagulase-negative Staphylococcus (CoNS) strains are a leading cause of arthroplastic infections, accounting for 15 to 37.5% of isolates recovered from peroperative samples (13). Staphylococcus epidermidis is the main species responsible for these infections and for other device-related bone and joint infections (BJI). There are some reports of true BJI caused by CoNS species other than S. epidermidis, including S. caprae (1), S. lugdunensis (24), and S. simulans (18). However, no prospective study has specifically addressed the species distribution of CoNS strains in BJI. Identification of CoNS strains to the species level has long been an obstacle preventing this question from being answered satisfactorily. PCR-based sequencing methods can now accurately identify a wide spectrum of Staphylococcus species (7,11,17). In this 4-year prospective study, we used sodA sequencing to identify CoNS species associated with BJI.All surgical procedures performed in the orthopedic department of Raymond Poincaré hospital (Garches, France) between January 1999 and December 2002 for proven or suspected BJI were studied prospectively. We included all procedures in which at least three independent samples were collected during the same operative procedure, at least one sample was positive for a CoNS strain, and no samples were positive for organisms other than CoNS strains. The samples were processed in a class 2 laminar-flow safety cabinet. A portion of the sample was Gram stained, and the remainder was used to inoculate 10 ml of Schaedler broth (BioMérieux, Marcy l'Etoile, France). After agitation, aliquots were used to inoculate chocolate agar plates (incubated in 5% CO 2 ) and blood agar plates (incubated aerobically and anaerobically). The plates were examined daily for 7 days. Broths were subcultured after 1 and 5 days. The "CoNS group" was identified by Gram staining, catalase testing, Slidex latex agglutination testing (BioMérieux), and tube coagulase testing (Bio-Rad, Marnes la Coquette, France). Antibiotic susceptibility was evaluated by the disk diffusion method on Mueller-Hinton agar (Bio-Rad). Strains were identified to the species level by partial sodA sequencing (17) as described recently by our group (21). We used the definitions and criteria recommended by the OSIRIS (Oxford Skeletal Infection Research and Intervention Service) group (2). CoNS...

This study evaluated the possible advantages provided by a genotypic method over commercially available biochemical systems for the identification of clinical isolates of coagulase-negative staphylococci (CNS). Partial sequencing of the sodA gene was performed for 168 coagulase-negative clinical isolates of staphylococci identified previously with the ID32 STAPH system. Of these, 101 (60.1%) were identified to the species level with ID32 STAPH, while 67 (39.9%) were misidentified or not identified with certainty. Sequencing of sodA proved useful for resolving all ambiguities or inconclusive identifications generated by the commercially available biochemical identification system.

We sequenced the adhesin-cell wall-anchoring domain of the atlE gene of 49 invasive and commensal Staphylococcus epidermidis strains. We identified 22 alleles, which could be separated into two main groups: group 1 (alleles 1 and 6 to 16, 32/49 strains) and group 2 (alleles 2 to 5 and 17 to 22, 17/49 strains). Allele 1 (the type strain sequence) was by far the most prevalent (21 of 49 strains). Multilocus sequence typing showed a clear relationship between the atlE allele and the sequence type (ST), with the "nosocomial" ST27 clone and closely related STs expressing group 1 alleles.Staphylococcus epidermidis is a ubiquitous commensal organism of human skin and mucous membranes and is one of the main bacterial agents involved in infections related to the presence of indwelling or implanted foreign bodies (10). AtlE, encoded by the atlE gene (8), is thought to play a key role in the pathogenicity of this bacterium, enabling it to adhere to the surface of implanted medical devices (19). AtlE is a bifunctional autolysin with an N-terminal alanine amidase domain, a central cell wall-anchoring (CWA) domain consisting of three repeats (R1 to R3), each about 165 amino acids long, and a C-terminal glucosaminidase domain. It is secreted as a proenzyme and is cleaved between R2 and R3 at the surface of the bacterium, generating two separate enzymes: a 60-kDa alanine amidase containing R1 and R2 at its C terminus and a 52-kDa glucosaminidase containing R3 at its N terminus. The products of AtlE processing have been shown to have adhesive properties (8), probably involving domains R1, R2, and R3 (9).Other autolysins from gram-positive bacteria able to mediate bacterial adhesion via their CWA domains have been described. These adhesins-autolysins include Aas from Staphylococcus saprophyticus (9), AtlC from Staphylococcus caprae (1, 2), and Ami from Listeria monocytogenes (14). The staphylococcal adhesins-autolysins AtlE, Aas, and AtlC appear to have different adhesion patterns (1, 8, 9). For example, unlike Aas (9), AtlE mediates binding to vitronectin but not to fibronectin (8). Thus, the adhesion patterns mediated by adhesins-autolysins clearly differ between species within the genus Staphylococcus, probably because of differences in the CWA domains of these molecules. We recently showed that the structure and function of the CWA domain of the adhesin-autolysin Ami vary within L. monocytogenes (15). Thus, adhesins-autolysins may also display intraspecific polymorphism, resulting in differences in binding capacity between strains of the same species. To date, atlE has been sequenced in only a few strains (6,8,25). It is therefore unclear whether the CWA domain of AtlE displays polymorphism in invasive and commensal strains. We investigated this possibility by sequencing the DNA region encoding the CWA domain of AtlE (atlE cwa ) in a large panel of S. epidermidis strains.We studied a total of 49 S. epidermidis strains, including 27 clinical strains from 27 individuals (RPC99P332, RPC99P469, RPC99P756, RPC99P1232, RPC99P1478, ...

No abstract