Contaminated ice used for BAL causes pseudo-outbreak of M. mucogenicum
Researchers linked a bronchoscopy-associated pseudo-outbreak of Mycobacterium mucogenicum to contaminated ice used for bronchoalveolar lavage in 15 patients.
According to the researchers, more than 50 outbreaks and pseudo-outbreaks have been associated with flexible bronchoscopy procedures, and contaminated ice has been implicated in multiple health care outbreaks.
In February 2017, a microbiology lab detected M. mucogenicum in nine bronchoscopy samples collected from eight patients at University of North Carolina Hospitals. The final investigation yielded 19 infected respiratory samples from 15 patients.
The outbreak investigation aimed to determine “whether this finding represented an outbreak or a pseudo-outbreak and on the source of the M. mucogenicum,” the researchers wrote.
Of the 15 involved patients, none had a clinical illness compatible with a nontuberculous mycobacteria infection, indicating that the isolates detected in the original samples were part of a pseudo-outbreak.
The investigators ruled out contaminated culture plates or reusable pipettes as a cause after assessing the lab’s culture methods. They also inspected the bronchoscopes and automated endoscope reprocessor (AER) and examined the bronchoscope reprocessing records, which included paper logs for minimum effective concentration documentation, AER records, filter change logs and periodic maintenance logs.
According to the study, the investigators evaluated the bronchoscopy methods, procedures and locations, which revealed the use of nonsterile ice mixed with sterile saline for the bronchoalveolar lavage to reduce the risk for bleeding. Samples taken from the two ice machines being used yielded positive cultures for M. mucogenicum.
“We were very pleasantly surprised to find none of our patients were infected and that this was a pseudo-outbreak,” Judie Bringhurst, MSN, RN, CIC, an infection preventionist at UNC Hospitals, told Infectious Disease News. “It is important to consider pseudo-outbreaks in evaluating a cluster of positive cultures linked to a procedure to prevent unnecessary diagnostic tests and/or treatment of patients.” – by Marley Ghizzone
Disclosures: The authors report no relevant financial disclosures.