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Nosocomial Mycobacterium fortuitum colonization from a contaminated ice machine
S Laussucq1, A L Baltch, R P Smith
1Respiratory Diseases Branch, Centers for Disease Control, Atlanta, Georgia 30333.
Abstract:
Between October 15 and November 18, 1985, 5 patients on a medical ward of the Albany VA Medical Center (Ward 8A) became colonized with Mycobacterium fortuitum. Because other patients in Ward 8A were at risk of developing disease with M. fortuitum, microbiologic surveillance to identify colonization in sputum was begun. By February 15, 1986, 30 colonized patients had been identified in this ward but none in another ward with a comparable patient population, which suggests a source unique to Ward 8A. Because water has been recognized as a source of opportunistic mycobacterial pathogens, we conducted a retrospective case-control study using a telephone survey questionnaire to examine a number of water exposures in 10 patients and 20 control subjects. Exposure to ice from the Ward 8A ice machine, but not to potable water, was associated with colonization with M. fortuitum. Large-volume water samples from a variety of sources were cultured for acid-fast bacilli. M. fortuitum was isolated only from the ice machine in Ward 8A. The ice machine was disconnected, and no additional patients became colonized. Although ice machines are infrequently implicated in nosocomial outbreaks, they represent a potential source for pathogens that survive or replicate in water.
Insights
An ice machine on Ward 8A was identified as the source of Mycobacterium fortuitum colonization in 30 patients. Disconnecting the machine stopped further patient colonization, highlighting water sources as potential reservoirs for nosocomial pathogens.
Area of Science:
- Infectious Diseases
- Hospital Epidemiology
- Microbiology
Background:
- Nosocomial outbreaks of opportunistic pathogens pose significant risks to patient health.
- Mycobacterium fortuitum, an acid-fast bacillus, can cause infections in vulnerable populations.
- Water systems in healthcare settings are recognized reservoirs for various microorganisms.
Purpose of the Study:
- To investigate the source of Mycobacterium fortuitum colonization among patients on Ward 8A.
- To identify potential risk factors associated with M. fortuitum colonization.
- To evaluate the role of water sources in the transmission of M. fortuitum.
Main Methods:
- Retrospective case-control study design.
- Microbiologic surveillance of patient sputum for M. fortuitum colonization.
- Telephone surveys to assess patient water exposure history.
- Environmental sampling of water sources, including an ice machine.
Main Results:
- Thirty patients on Ward 8A were identified as colonized with M. fortuitum.
- Exposure to ice from the Ward 8A ice machine was significantly associated with colonization.
- M. fortuitum was isolated exclusively from the Ward 8A ice machine.
- Disconnection of the ice machine halted further patient colonization.
Conclusions:
- The ice machine on Ward 8A served as the source of M. fortuitum outbreak.
- Healthcare-associated ice machines can be a potential source of opportunistic mycobacterial pathogens.
- Environmental water sources require careful monitoring and maintenance to prevent nosocomial infections.