A Cluster ofMycobacterium wolinskyiSurgical Site Infections at an Academic Medical Center

Abstract

ObjectiveTo study a cluster ofMycobacterium wolinskyisurgical site infections (SSIs).DesignObservational and case-control study.SettingAcademic hospital.Patients.Subjects who developed SSIs withM. wolinskyifollowing cardiothoracic surgery.MethodsElectronic surveillance was performed for case finding as well as electronic medical record review of infected cases. Surgical procedures were observed. Medical chart review was conducted to identify risk factors. A case-control study was performed to identify risk factors for infection; Fisher exact or Kruskal-Wallis tests were used for comparisons of proportions and medians, respectively. Patient isolates were studied using pulsed-field gel electrophoresis (PFGE). Environmental microbiologic sampling was performed in operating rooms, including high-volume water sampling.ResultsSix definite cases ofM. wolinskyiSSI following cardiothoracic surgery were identified during the outbreak period (October 1, 2008–September 30, 2011). Having cardiac surgery in operating room A was significantly associated with infection (odds ratio, 40;P= .0027). Observational investigation revealed a cold-air blaster exclusive to operating room A as well a microbially contaminated, self-contained water source used in heart-lung machines. The isolates were indistinguishable or closely related by PFGE. No environmental samples were positive forM. wolinskyi.ConclusionsNo single point source was established, but 2 potential sources, including a cold-air blaster and a microbially contaminated, self-contained water system used in heart-lung machines for cardiothoracic operations, were identified. Both of these potential sources were removed, and subsequent active surveillance did not reveal any further cases ofM. wolinskyiSSI.Infect Control Hosp Epidemiol2014;35(9):1169-1175