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Background: Outbreaks associated to bronchoscopes are infrequent, but are known to occur in association with mechanical defects in the device, or breakdowns in disinfection technique. In June 2010, our Infection Prevention Program noted an increase in cases of S. maltophilia (SM) isolated from bronchoalveolar lavage (BAL) specimens from our Medical Intensive Care Unit (MICU) - up to 4 in single month compared to 4 for all previous months that year.
Objective: Conduct an outbreak investigation to determine if there was a common source of the SM cluster in our MICU unit, and contain the outbreak.
Methods: Outbreak investigation consisting of a retrospective chart review, interview of personnel, epidemiological surveillance, and microbiological testing. Cases were defined as (1) All patients who had positive cultures for SM from any site, and (2) Patients admitted to the MICU and who had a bronchoscopy, from 05/2010 to 07/2010.
Results: We identified 6 patients with positive BAL cultures for SM during this time period. one bronchoscope was positive for two SM isolates on two different occasions (surveillance #39-5 and #39-8, Figure 1). 14 additional environmental cultures were negative. These isolates were tested for clonality via DNA fingerprinting. Cultures from this bronchoscope (isolate #39-5) were matched to patient isolates #39-3 and #39-6. The bronchoscope was removed from service and re-sterilized. After reculturing, the bronchoscope was still positive for SM (#39-8), which was indistinguishable from patient isolate #39-7. The bronchoscope was sent to the manufacturer where it was found to have a dent at the polyurethane at the insertion tube and debris at the biopsy inlet T-piece. The bronchoscope was repaired, and follow up surveillance cultures have been negative. It has since been placed back on service. Rates of isolation of SM in the MICU have returned to baseline.
Conclusions: A defective bronchoscope was linked to the development of SM pneumonia in 3 of 6 patients in this outbreak. Several mechanical defects were determined to be the likely cause of this failure. A dedicated Infection Control team, ongoing surveillance efforts, and thoughtful use of molecular identification techniques were essential in identifying the source of this outbreak. It is important for infection prevention personnel to remain vigilant to recognize the potential of endoscopic devices to act as vectors for infections.
