Nosocomial Mycobacterium gordonae pseudoinfection from contaminated ice machines

Area of Science:

• Microbiology
• Clinical Laboratory Science
• Infectious Disease Epidemiology

Background:

• Mycobacterium gordonae is a slow-growing, non-pathogenic saprophyte commonly found in soil and water.
• An unusual surge in laboratory-confirmed Mycobacterium gordonae isolates from clinical specimens was observed over a 12-month period.
• The high number of isolates contrasted sharply with historical data, suggesting a potential outbreak or contamination event.

Purpose of the Study:

• To investigate the cause of a pseudoepidemic of Mycobacterium gordonae infections.
• To identify the source of contamination leading to the increased isolation of M. gordonae.
• To implement control measures and prevent future occurrences.

Main Methods:

• Clinical specimens were cultured for mycobacteria over a 12-month period.
• Laboratory reagents, deionized water, and clinical samples were monitored for contamination.
• Hospital-wide environmental cultures were performed, focusing on water sources.
• Investigated the role of ice machines in the observed contamination.

Main Results:

• Thirty-two clinical specimens yielded Mycobacterium gordonae, a significant increase from previous years.
• Aseptic clinical samples and laboratory reagents remained negative, ruling out typical laboratory contamination.
• Environmental cultures identified contaminated ice machines as the source of M. gordonae.
• Cleaning the ice machines led to a rapid decline in M. gordonae isolations.

Conclusions:

• Improperly maintained ice machines can serve as a source of Mycobacterium gordonae pseudoinfection in clinical settings.
• Environmental hygiene and regular maintenance of water-associated equipment are critical for preventing laboratory-associated pseudooutbreaks.
• This study highlights a novel source of pseudoinfection previously unreported in the literature.