Staphylococcus aureus small colony variants in prosthetic joint infection.
Clinical Infectious Diseases October 15, 2006 V.43 N.8 P.961-7.
Sendi P1, Rohrbach M, Graber P, Frei R, Ochsner PE, Zimmerli W.
1Unit of Infectious Diseases, Basel University Medical Clinic Liestal, Liestal, CH-4410, Switzerland. firstname.lastname@example.org
Small colony variants of Staphylococcus aureus tend to persist despite antimicrobial therapy, especially when involved in implant-associated infections.
We analyzed 5 cases of hip prosthesis-associated infections due to small colony variants, including their course prior to identification of the pathogen. Biopsy investigations included microbiological examination and, in 1 case, transmission electron microscopy to detect intracellular bacteria in nonprofessional phagocytes. A treatment concept was elaborated on the basis of a published algorithm and patients were managed accordingly.
The patients’ mean age was 62.2 years. All patients experienced treatment failures prior to isolation of small colony variants, despite as many as 3 surgical revisions and up to 22 months of antibiotics. Transmission electron microscopy performed on biopsy specimens from periprosthetic tissue revealed intracellular cocci in fibroblasts. All prostheses were removed without implanting a spacer, and antimicrobial agents were administered for 5.5-7 weeks. Reimplantation of the prosthesis was performed for 4 patients. Follow-ups were uneventful in all 5 cases.
In the case of a poor response to adequate antimicrobial and surgical treatment in implant-associated staphylococcal infections, small colony variants should be considered and actively sought. In our case series, a 2-stage exchange without implantation of a spacer combined with antimicrobial therapy for an implant-free interval of 6-8 weeks was associated with successful outcome, with a mean follow-up of 24 months.
Entry filed under: Antimicrobianos, Bacterias, Epidemiología, Health Care-Associated Infections, Infecciones nosocomiales, Infecciones osteo-articulares-musculares, Infecciones relacionadas a prótesis, Infecciones sitio quirurgico, Metodos diagnosticos, Resistencia bacteriana, Sepsis.