The investigation of a case of methicillin-resistant Staphylococcus aureus found in a bone specimen taken during a total hip allograft

Abstract

ISSUE: Methicillin-resistant Staphylococcus aureus (MRSA) was found isolated from a bone specimen from a patient having a total hip allograft. The allograft sample, obtained in the operating room just prior to implantation, was sent to the laboratory for testing and was found to be positive for MRSA. The patient received both oral and intravenous antibiotic medications. Due to the long-term risks associated with MRSA within the allograft, the patient eventually had to have a peripherally inserted central catheter (PICC line) to facilitate his long-term antibiotic use. A number of additional factors contributed to the severity of this case, including the multidisciplinary teams that had to be consulted for this patient, the financial costs of the patient's added stay in the hospital, as well as the emotional stress inflicted on the patient. PROJECT: A thorough investigation by the infection control team included a review of the procedures in the bone bank and the microbiology laboratory and a screening of the patient and staff present in the operating room (n = 15) to rule out carriage and shedding of MRSA. RESULTS: The investigation revealed no deficiencies in bone bank procedures and no apparent opportunities for contamination. Screening of operating room and microbiology staff identified no carriage of MRSA. MRSA was isolated from 19 specimens received in the lab on the same day as the bone specimen. Only one specimen was received within 3 hours of the specimen in question. This specimen, a wound swab, was received approximately 30 minutes after the operating room specimen was received. The MRSA isolated from this specimen was indistinguishable by pulsed-field gel electrophoresis (PFGE) and Scheck typing to the isolate from the bone graft. No other MRSA of this type have been identified in our laboratory within the last year. LESSONS LEARNED: Laboratory contamination of specimens has been reported with Mycobacterium tuberculosis and vancomycin-resistant Enterrococcus but has not been reported with other organisms. Laboratories should routinely audit their procedures for handling sterile site specimens. Infection control practitioners should be aware that laboratory contamination of sterile site specimens requiring complex handling may occur. Episodes of laboratory contamination may be associated with significant costs and negative impacts on patient care.