A Cluster of Pseudo-Outbreaks in the Endoscopy Suite
Over six weeks, three patients who underwent bronchoscopy in the same suite have respiratory specimens growing the same nontuberculous mycobacterium. The isolates have identical susceptibility patterns. The suite uses an automated endoscope reprocessor; logs show the high-level disinfectant was changed on schedule, but two of the three procedures followed a reprocessing cycle in which the automated reprocessor's cycle was aborted and manually restarted. Staff report that the reprocessor's alarm has been 'intermittent' for months. No patient-to-patient contact occurred. The hospital's infection preventionist wants to know whether this is a true cluster or coincidence before notifying public health.
1. Assess whether this is a true cluster and outline the investigation.
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Three cases of the same organism with identical susceptibility patterns, linked to a single procedural suite, is a signal that warrants investigation, not dismissal as coincidence. The probability of three unrelated patients yielding the same organism with the same susceptibility profile is low. The reprocessor alarm history and the aborted-and-restarted cycles are plausible mechanisms for inadequate high-level disinfection.
The investigation: (1) review all bronchoscopy cases in the window and culture/clinical outcomes to establish the case definition and look for additional cases; (2) culture the reprocessor, the disinfectant, and the endoscopes; (3) review reprocessor maintenance and alarm logs; (4) review manual reprocessing steps after an aborted cycle; (5) interview staff about practice. Molecular typing of the isolates (e.g., whole-genome sequencing) would strengthen or refute the link. The key point is that the investigation should proceed while the question is open-waiting for certainty before acting is the wrong order.
2. What immediate actions should be taken, and when should public health be notified?
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Immediate actions: stop using the affected reprocessor until it is serviced and verified; quarantine the implicated endoscopes pending culture; review and reinforce manual reprocessing after any aborted cycle; and notify clinical staff so they can watch for infections in exposed patients. Exposed patients may need notification and clinical follow-up.
Public health notification: a suspected healthcare-associated cluster of the same organism linked to a device reprocessing failure meets the threshold for prompt notification to the local health department and, depending on jurisdiction, the manufacturer. The infection preventionist's instinct to confirm before notifying is understandable, but the standard is suspicion with a plausible mechanism, not proof. Notification enables additional resources and protects other patients. Document the timeline and decisions throughout.