Sendi Parham, Rohrbach Markus, Graber Peter, Frei Reno, Ochsner Peter E, Zimmerli Werner
Unit of Infectious Diseases, Basel University Medical Clinic Liestal, Liestal, CH-4410, Switzerland.
Clin Infect Dis. 2006 Oct 15;43(8):961-7. doi: 10.1086/507633. Epub 2006 Sep 8.
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.
金黄色葡萄球菌小菌落变异株往往在抗菌治疗后仍持续存在，尤其是在植入物相关感染中。
我们分析了5例由小菌落变异株引起的髋关节假体相关感染病例，包括病原体鉴定之前的病程。活检调查包括微生物学检查，其中1例进行了透射电子显微镜检查以检测非专职吞噬细胞内的细菌。根据已发表的算法制定了治疗方案，并据此对患者进行管理。
患者的平均年龄为62.2岁。所有患者在小菌落变异株分离之前均经历了治疗失败，尽管进行了多达3次手术翻修和长达22个月的抗生素治疗。对假体周围组织活检标本进行的透射电子显微镜检查显示成纤维细胞内有球菌。所有假体均被移除，未植入间隔物，并给予抗菌药物治疗5.5 - 7周。4例患者进行了假体再植入。所有5例患者的随访均无异常。
在植入物相关葡萄球菌感染中，若对充分的抗菌和手术治疗反应不佳，应考虑并积极寻找小菌落变异株。在我们的病例系列中，两阶段置换且不植入间隔物并结合抗菌治疗6 - 8周的无植入物间隔期与成功结果相关，平均随访24个月。
