Investigation into a Pseudo-outbreak of Mycobacterium Arupense in Respiratory Specimens

ISSUE: Three patients with birth weights < 1000 grams had PA identified in blood cultures within 3 weeks in our 50 bed NICU. Patient’s bed spaces were in close physical proximity. All 3 patients received ventilator support and 2 had PA isolated from respiratory specimens. A water source was suspected. A PubMed search revealed previous PA outbreaks associated with improper high level disinfection (HLD) of ventilator temperature probes (TPs) and artificial nails. PROJECT: Task force of key stakeholders including IP, NICU Nursing and Medical staff, Respiratory Therapy (RT) and Pharmacy collaborated to review the cases and NICU practices. Visual checks for artificial nails were conducted. Procedures for HLD of TPs and cleaning process for humidified giraffe beds were reviewed. Environmental testing of giraffe beds and TPs was conducted. Other areas investigated included: storage of laryngoscope blades, endotracheal tube taping procedures, nurse staffing ratios, tracking of ventilators and giraffe beds to specific patients and delineation of cleaning responsibilities. PA isolates were sent formolecular testing and 2 of 3 were indistinguishable. RESULTS: While observing the HLD of the TPs, it was noted that the entire probe did not come in contact with disinfectant. Laryngoscope blades were not stored appropriately to prevent contamination; there was not a clear delineation of cleaning responsibilities; and there was not a mechanism to track which ventilator/giraffe bed was used on what patient. Delineation of cleaning responsibilities was defined to include all equipment and surfaces. A tracking mechanism was developed for ventilator/ giraffe beds and laryngoscope blades were stored in a sealed bag. The HLD of the TPs was moved from the unit to a centralized RT area. LESSON LEARNED: Prompt identification of a cluster of infections and swift collaboration of key stakeholders proved effective in mitigating a potential outbreak. This experience led to a collective buy-in of IP recommendations by all NICU staff. The NICU CLABSI rate has since declined and the days between infections are the greatest since 2004. The TPs were suspected as potential source although all environmental testing was negative. No further cases of PA bacteremia were identified.