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Molecular typing for investigating an outbreak of Candida krusei
1Division of Infectious Diseases, Northwestern University Medical School, Chicago, IL 60611, USA.
Abstract:
Invasive infections due to Candida krusei are often observed in immunocompromised patients who have received prior therapy with fluconazole, although infection has also occurred in patients in the absence of this antifungal agent. From August 25 through September 19, 1995, we identified four patients with C. krusei fungemia on our hematology/oncology unit. Molecular typing of all the isolates was performed by restriction endonuclease analysis of genomic DNA using HinfI. A total of 7 patients found to be colonized or infected with C. krusei were matched with 14 controls. There was no difference between the cases and controls with respect to underlying disease, duration of hospitalization, or neutropenia. The numbers of days of hyperalimentation, corticosteroids, and antibiotics were similar between both groups. The mean number of antibiotics was greater in the cases versus controls (5.0 versus 2.5; p = .003). There was no difference with respect to total dose or duration of fluconazole administration. Molecular typing of the isolates revealed that four had identical DNA banding patterns, plus another two that differed by one band and were considered related. Three historical strains were unrelated. In conclusion, this report demonstrates that molecular typing can be used to define clonality and, thereby, support increased infection control practices to eliminate such outbreaks when evidence of clonal spread is present.
Insights
Molecular typing identified clonal spread of Candida krusei in a hospital outbreak, highlighting the need for enhanced infection control. This supports targeted interventions to prevent further invasive fungal infections.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Invasive Candida krusei infections are a concern in immunocompromised patients, sometimes occurring despite fluconazole therapy.
- Candida krusei fungemia outbreaks necessitate understanding transmission dynamics.
Purpose of the Study:
- To investigate an outbreak of Candida krusei fungemia on a hematology/oncology unit.
- To determine the clonality of Candida krusei isolates using molecular typing.
Main Methods:
- Molecular typing of Candida krusei isolates by restriction endonuclease analysis of genomic DNA (HinfI).
- Case-control study matching 7 infected/colonized patients with 14 controls.
- Analysis of patient factors including underlying disease, hospitalization, neutropenia, and supportive care.
Main Results:
- Molecular typing revealed clonal spread among four of the seven Candida krusei isolates, with two others being related.
- No significant differences were found in underlying disease, hospitalization duration, or neutropenia between cases and controls.
- Cases received a higher mean number of antibiotics compared to controls (5.0 vs. 2.5; p = .003).
Conclusions:
- Molecular typing is effective in identifying clonal spread of Candida krusei during outbreaks.
- Evidence of clonal spread supports implementing enhanced infection control measures.
- Targeted interventions are crucial to contain and eliminate Candida krusei outbreaks in healthcare settings.