Pseudo-outbreak of stenotrophomonas maltophilia and Acinetobacter baumannii by a contaminated bronchoscope in an intensive care unit

Background: Stenotrophomonas maltophilia and Acinetobacter baumannii are serious offending agents of nosocomial pneumonia and of serious morbidity and mortality in intensive care units (ICU). We report an unexpected sudden surge in cases of pneumonias caused by the above organisms in an intensive care unit of a community hospital in a span of two months. The source was traced back to a contaminated bronchoscope. Materials and Methods: The records from the patients with diagnosis of pneumonia with the above organisms were retrospectively reviewed. Specimens from the ports and channels of the bronchoscope that was suspected to be the cause were taken and microbiologically analyzed. Results: Two patients with Acinetobacter and four patients with Stenotrophomonas positive bronchoalveolar lavage (BAL) fluid cultures were identified within a 2-month period in one of our two intensive care units. All of the patients were mechanically ventilated, and had clinical features of pneumonia. Their bronchoscopies were performed and their BALs were obtained by a scope with an identical serial number. The microbiologic evaluation of samples taken from the suspected scope revealed that it was improperly decontaminated between procedures. After implementation of strict and revised decontamination protocol, there were no further cases of pneumonia caused by the above organisms in a span of several months in mechanically ventilated patients. Conclusion: Inadequate disinfection of bronchoscopes and cross contamination between patients could be a potential cause of ventilator-associated pneumonia. Strict implementation of infection prevention guidelines in bronchoscopies of mechanically ventilated patients could prevent cases of ventilator-associated pneumonias by nosocomial agents including S. maltophilia and A. baumannii.