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Pseudo-outbreak of Mycobacterium fortuitum due to contaminated ice machines
Vincent J Labombardi1, Anne Marie O'brien, Jay W Kislak
1Department of Pathology, St. Vincent's Hospital, New York, New York 10011, USA.
Background:
An almost 4-fold increase from normal baseline levels in the isolation of Mycobacterium fortuitum from respiratory tract specimens was observed. The majority of these isolates were obtained from patients residing on 1 of 2 wards, prompting an epidemiologic investigation.
Methods:
In addition to patient specimens, environmental cultures were collected from various water sources on the 2 affected wards. Samples were also collected from uninvolved areas of the hospital. All specimens were cultured with use of a continuously monitored broth system for the isolation of mycobacteria.
Results:
The respiratory tracts of 19 patients were colonized by M fortuitum. Surveillance cultures obtained from uninvolved areas of the hospital were either negative for mycobacteria or were colonized by M avium complex or M gordonae. Two ice machines, servicing the affected areas each, were colonized by M fortuitum in multiple cultures.
Conclusions:
The M fortuitum pseudo-outbreak was due to contaminated ice machines located on each of the affected units. After removal and replacement of the ice machines, the pseudo-outbreak resolved.
Insights
A rise in Mycobacterium fortuitum respiratory infections was investigated. Contaminated ice machines on hospital wards were identified as the source, and their removal resolved the outbreak.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Observed a significant increase in Mycobacterium fortuitum isolations from respiratory specimens.
- Most isolates originated from patients on two specific hospital wards, triggering an investigation.
Purpose of the Study:
- To identify the source of increased Mycobacterium fortuitum isolates.
- To investigate the epidemiological link between patient infections and environmental factors.
Main Methods:
- Collected patient respiratory specimens and environmental cultures from water sources on affected and unaffected wards.
- Utilized a continuously monitored broth system for mycobacterial isolation.
- Performed surveillance cultures in various hospital areas.
Main Results:
- Identified 19 patients with respiratory tract colonization by Mycobacterium fortuitum.
- Environmental cultures from two ice machines servicing the affected wards yielded positive results for Mycobacterium fortuitum.
- Surveillance cultures from unaffected hospital areas were negative or showed different mycobacterial species.
Conclusions:
- Contaminated ice machines on the affected wards were the cause of the Mycobacterium fortuitum pseudo-outbreak.
- Replacement of the contaminated ice machines led to the resolution of the pseudo-outbreak.