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BACKGROUND: Non-tuberculous mycobacteria (NTM) are ubiquitous soil and water microorganisms that can transiently colonize human hair and body surfaces, and are under recognized causes of surgical site infections. In January 2014, non-pulmonary NTM infections became reportable in Oregon. We describe the epidemiologic investigation of a 5-year cluster of NTM infections associated with joint prosthesis surgeries to determine their extent, source, and transmission, and to identify control measures.
METHODS: A case was defined as any culture-positive NTM SSI identified since October 2010 that occurred within 1 year of knee or hip prosthetic joint surgery. We queried the Oregon Health Alert Network, Epi-X, and Medwatch for additional cases, reviewed National Healthcare Safety Network data, abstracted medical charts, interviewed infection preventionists, observed surgeries, performed a matched case-control study, and collected environmental specimens.
RESULTS: We identified 7 Mycobacterium fortuitum and 2 Mycobacterium goodii SSIs involving 4 knee and 5 hip joint prostheses with onset October 2010–September 2014. NTM infections were confirmed 69–157 (median: 85.5) days post-operatively, with 3 at ≥90 days. Patients were 46–79 (median: 66) years of age, and 5 were female; none had signs of infection at prosthesis placement. Surgeries had been performed in 4 hospitals in one region of Oregon by 6 different surgeons from 3 non-overlapping surgical groups. All prostheses were produced by Manufacturer A; Representative B from Manufacturer A was documented as present during 8 of the 9 surgeries. Surgery observations revealed that manufacturer representatives do not consistently abide by national guidelines for operative room infection control. We identified significant associations between NTM SSI and Manufacturer A (unadjusted matched odds ratio [mOR]: 27.7, 95% confidence interval [95%CI]: 5.3–∞; P = 0.0002) and NTM SSI and Representative B (mOR: 32.4, 95%CI: 6.3–∞; P = 0.0001). No other NTM SSIs involving Manufacturer A prostheses were identified in Oregon or the U.S. during this time period. Representative B reported daily home hot-tub use before working in operating rooms at hospitals. Environmental cultures isolated M. fortuitum from Representative B’s hands, but not from the hot tub. We recommended improved adherence to hospital operating room infection control standards, and disinfection of Representative B’s hot tub.
CONCLUSIONS: Clusters of NTM SSIs can be caused by transiently colonized individuals who are present during surgeries. Adherence to national perioperative guidelines to prevent surgical site infections by all persons present in the operating room is essential to prevent SSIs.