title: Characterization of Staphylococcus epidermidis and Staphyloccocus warneri small-colony variants associated with prosthetic-joint infections.
abstract: We determined the frequency of isolation of staphylococcal small-colony variants (SCVs) from 31 culture-positive patients undergoing revision of total hip prosthesis for aseptic loosening or presumed prosthetic-joint infection (PJI). We analysed auxotrophy of cultured SCVs, their antimicrobial susceptibility profiles and their biofilm-forming capacity. Eight SCV strains were cultivated from six (19 %) patients. All SCVs were coagulase-negative staphylococci (CNS) with Staphylococcus epidermidis as the predominant species; there was also one Staphylococcus warneri SCV. The SCVs were auxotrophic for haemin, with one strain additionally auxotrophic for menadione. We noted the presence of two phenotypically (differences concerning antimicrobial susceptibility) and genetically distinct SCV strains in one patient, as well as the growth of two genetically related SCVs that differed in terms of their morphology and the type of auxotrophy in another. Seven out of eight SCVs were resistant to meticillin and gentamicin. In addition, antibiotic sensitivity testing revealed three multidrug-resistant SCV-normal-morphology isolate pairs. One S. epidermidis SCV harboured icaADBC genes and was found to be a proficient biofilm producer. This paper highlights the involvement of CNS SCVs in the aetiology of PJIs, including what is believed to be the first report of a S. warneri SCV. These subpopulations must be actively sought in the routine diagnosis of implant-associated infections. Moreover, in view of the phenotypic and genetic diversity of some SCV pairs, particular attention should be paid to the investigation of all types of observed colony morphologies, and isolates should be subjected to antimicrobial susceptibility testing.
authors.affiliation: Department of Medical Microbiology, Medical University of Lublin, Chodźki 1 Street, 20-093 Lublin, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Bogut
authors.affiliation: Department of Medical Microbiology, Medical University of Lublin, Chodźki 1 Street, 20-093 Lublin, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Niedźwiadek
authors.affiliation: Department of Medical Microbiology, Medical University of Lublin, Chodźki 1 Street, 20-093 Lublin, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Kozioł-Montewka
authors.affiliation: Department of Medical Microbiology, Medical University of Lublin, Chodźki 1 Street, 20-093 Lublin, Poland.
authors.forename: Dagmara
authors.initials: D
authors.lastname: Strzelec-Nowak
authors.affiliation: Orthopaedics and Traumatology Ward, Clinical Hospital No. 4, Jaczewskiego 8 Street, 20-954 Lublin, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Blacha
authors.affiliation: Orthopaedics and Traumatology Ward, Clinical Hospital No. 4, Jaczewskiego 8 Street, 20-954 Lublin, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Mazurkiewicz
authors.affiliation: Orthopaedics Ward, Public Clinical Hospital of Prof. Adam Gruca, Konarskiego 13 Street, 05-400 Otwock, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Marczyński
authors.affiliation: Research Centre for Innovation, Pope John Paul II State School of Higher Education in Biała Podlaska, Sidorska 105 Street, 21-500 Biała Podlaska, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Plewik
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001168:Arthritis / Q000382:microbiology*; D018441:Biofilms / Q000254:growth & development; D016000:Cluster Analysis; D003030:Coagulase / Q000378:metabolism; D006427:Hemin / Q000378:metabolism; D006801:Humans; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D016459:Prosthesis-Related Infections / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000382:microbiology*; D013210:Staphylococcus / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D003030:Coagulase; D037521:Virulence Factors; D006427:Hemin