Investigation of a cluster of rapidly growing mycobacteria infections associated with joint replacement surgery in a Kentucky hospital, 2013–2014 with 8-year follow-up

Abstract

Background: We describe the investigation of a nosocomial outbreak of rapidly growing mycobacteria (RGM) infections and the results of mitigation efforts after 8 years. Methods: A cluster of RGM cases in a Kentucky hospital in 2013 prompted an investigation into RGM surgical site infections following joint replacement surgery. A case-control study was conducted to identify risk factors. Results: Eight cases were identified, 5 caused by M. wolinskyi and 3 by M. goodii. The case-control study showed the presence of a particular nurse in the operating room was significantly associated with infection. Environmental sampling at the nurse's home identified an outdoor hot tub as the likely source of M. wolinskyi, confirmed by pulsed-field gel electrophoresis and whole genome sequencing. The hot tub reservoir was eliminated, and hospital policies were revised to correct infection control lapses. No new cases of RGM infections have been identified as of 2021. Discussion: Breaches in infection control practices at multiple levels may have led to a chain of infection from a nurse's hot tub to surgical sites via indirect person-to-person transmission from a colonized health care worker (HCW). Conclusions: The multifactorial nature of the outbreak's cause highlights the importance of overlapping or redundant layers of protection preventing patient harm. Future investigations of RGM outbreaks should consider the potential role of colonized HCWs as a transmission vector.