Clinical and operational impact of a four-year-long bronchoscopy-associated pseudo-outbreak of Mycobacterium mucogenicum.

OBJECTIVE To report on the investigation of a pseudo-outbreak of Mycobacterium mucogenicum and examine its clinical and operational impact. DESIGN Outbreak investigation, retrospective cohort study. SETTING Academic medical center in Los Angeles, California. PATIENTS Patients whose bronchoalveolar lavage (BAL) cultures grew M. mucogenicum from 2020-2024. METHODS We performed an institutional outbreak investigation of M. mucogenicum, reviewed electronic medical records of a subset of affected patients (2023-2024), and assessed the operational impact. RESULTS The incidence of M. mucogenicum in BAL cultures at Hospital A increased from 6.1% (29/473) in 2020 to 18.6% (29/156) in the first quarter of 2024. Epidemiologic investigation revealed non-sterile ice baths used to cool uncapped sterile syringes during bronchoscopy procedures as the contamination source. Next generation sequencing linked clinical isolates to M. mucogenicum recovered from a perioperative ice machine. Nearly all (157/160) clinical isolates grew from nocardia media rather than acid-fast bacilli media. Among 154 patients, including 51 (33.1%) who were highly immunocompromised, no true infections were identified. Thirty-nine (25.3%) patients were referred to infectious diseases for consultation, seven (4.5%) underwent additional workup, and only one received targeted treatment. The pseudo-outbreak incurred 458 hours of microbiology technologist and infection preventionist time and cost the laboratory $88,426. CONCLUSIONS A four-year pseudo-outbreak of M. mucogenicum traced to contaminated ice baths used during bronchoscopy resulted in unnecessary infectious disease referrals and substantial operational and financial burden to the institution. Avoidance of non-sterile ice use in procedures prevents costly and burdensome pseudo-outbreaks of environmental mycobacteria in healthcare settings.

• Publication year

  2026

• Venue

  Infection control and hospital epidemiology

• Publication date

  2026-02-09

• Fields of study

  Medicine, Environmental Science

• Identifiers
  DOI 10.1017/ice.2026.10399PMID 41657004
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• No claims are published for this paper.

• No concepts are published for this paper.

• Principles of diagnostic stewardship: A practical guide from the Society for Healthcare Epidemiology of America Diagnostic Stewardship Task Force

  2023cited by this paper
• How clean is your ice machine ? Revealing microbial amplification and presence of opportunistic pathogens in hospital ice-water machines.

  2023cited by this paper
• A bronchoscopy-associated pseudo-outbreak of Mycobacterium chelonae and Mycobacterium mucogenicum associated with contaminated ice machine water and ice

  2023cited by this paper
• Accurate subspecies-level identification of clinically significant Mycobacterium avium and Mycobacterium intracellulare by whole-genome sequencing.

  2023cited by this paper
• Mycobacterium abscessus Cluster in Cardiac Surgery Patients Potentially Attributable to a Commercial Water Purification System

  2023cited by this paper
• Physical Measures to Reduce Exposure to Tap Water–Associated Nontuberculous Mycobacteria

  2020cited by this paper
• Bronchoscope-Related Outbreaks and Pseudo-Outbreaks: CDC Consultations—United States, 2014–2019

  2020cited by this paper
• A bronchoscopy-associated pseudo-outbreak of Mycobacterium mucogenicum traced to use of contaminated ice used for bronchoalveolar lavage

  2019cited by this paper
• Hiding in Plain Sight: Contaminated Ice Machines Are a Potential Source for Dissemination of Gram-Negative Bacteria and Candida Species in Healthcare Facilities

  2018cited by this paper
• Performance of RGM Medium for Isolation of Nontuberculous Mycobacteria from Respiratory Specimens from Non-Cystic Fibrosis Patients

  2018cited by this paper
• Pseudo-outbreak of Mycobacterium gordonae Following the Opening of a Newly Constructed Hospital at a Chicago Medical Center

  2014cited by this paper
• Outbreak of Mycobacterium mucogenicum Bloodstream Infections among Patients with Sickle Cell Disease in an Outpatient Setting

  2012cited by this paper
• Molecular Typing of Mycobacterium chelonae Isolates From a Pseudo-outbreak Involving an Automated Bronchoscope Washer

  2008cited by this paper
• Multiphasic Approach Reveals Genetic Diversity of Environmental and Patient Isolates of Mycobacterium mucogenicum and Mycobacterium phocaicum Associated with an Outbreak of Bacteremias at a Texas Hospital

  2008cited by this paper
• Outbreak of Mycobacterium mucogenicum bacteraemia due to contaminated water supply in a paediatric haematology-oncology department.

  2008cited by this paper
• An Outbreak of Bacteremias Associated With Mycobacterium mucogenicum in a Hospital Water Supply

  2004cited by this paper
• Pseudo-outbreak of Mycobacterium fortuitum on a Human Immunodeficiency Virus Ward: transient respiratory tract colonization from a contaminated ice machine.

  2002influential reference
• Occurrence of Nontuberculous Mycobacteria in Environmental Samples

  1999cited by this paper
• Nosocomial outbreaks/pseudo-outbreaks caused by nontuberculous mycobacteria.

  1998cited by this paper
• Pseudoepidemic of Mycobacterium fortuitum in bone marrow cultures.

  1987influential reference

• No citing papers are available for this paper.