Heterogeneity of Staphylococcus epidermidis in prosthetic joint infections: time to reevaluate microbiological criteria?

AbstractProsthetic joint infection (PJI) is a feared and challenging to diagnose complication after arthroplasty, withStaphylococcus epidermidis as the major pathogen. One important criteria to define PJI is the detection of phenotypically indistinguishable microorganisms with identical antibiotic susceptibility pattern in at least two different samples. However, owing to phenotypical variation within genetic clones and clonal variation within a phenotype, the criteria may be ambiguous. We investigated the extent of diversity among coagulase-negative staphylococci (CoNS) in PJI and characterisedS. epidermidis isolates from PJI samples, specifically multipleS. epidermidis isolates identified in individual PJI patients. We performed a retrospective cohort study on 62 consecutive patients with PJI caused by CoNS from two hospitals in Northern Sweden. In 16/62 (26%) PJIs, multipleS. epidermidis isolates were available for whole-genome analyses. Hospital-adapted multidrug-resistant genetic clones ofS. epidermidis were identified in samples from 40/62 (65%) of the patients using a combination of pulsed-field gel electrophoresis and multilocus sequence typing. Whole-genome sequencing showed the presence of multiple sequence types (STs) in 7/16 (44%) PJIs where multipleS. epidermidis isolates were available. Within-patient phenotypical variation in the antibiotic susceptibility and/or whole-genome antibiotic resistance gene content was frequent (11/16, 69%) among isolates with the sa...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research