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Whole Genome Sequencing of Candida glabrata for Detection of Markers of Antifungal Drug Resistance
Published on: December 28, 2017
Phenotypic and genotypic differences between bloodstream and non-blood Candida krusei isolates: implications for
Ying Zhao1,2, Han Wang1,2, Jinhan Yu1
1Department of Laboratory Medicine, State Key Laboratory of Complex, Severe, and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Abstract:
Candida krusei is an opportunistic pathogen with intrinsic resistance to fluconazole. This study analyzed 174 C. krusei isolates from bloodstream infections (BSI, n = 115) and non-blood sources (n = 59). Biochemical profiling using the VITEK 2 YST ID Card revealed a significant difference in the TyrA reaction between BSI and non-blood isolates (P < 0.05). Antifungal susceptibility testing via CLSI broth microdilution and Sensititre YeastOne showed that BSI isolates were more susceptible to echinocandins and azoles than non-blood strains, with minor MIC discrepancies between methods. Microsatellite genotyping at eight loci demonstrated high genetic diversity. Notably, a cluster of respiratory isolates from COVID-19 patients suggested potential nosocomial transmission. The integration of phenotypic, susceptibility, and genotypic data highlights possible virulence traits and epidemiological patterns. These findings may support the development of tailored antifungal therapies and improved infection control, particularly for high-risk populations such as ICU and COVID-19 patients.IMPORTANCEBloodstream infections caused by C. krusei are associated with high mortality rates and limited therapeutic options, emphasizing the need to better understand the factors contributing to its pathogenicity and invasive potential. This study provides critical insights into the biology and clinical impact of C. krusei. By integrating biochemical, antifungal susceptibility, and genotypic analyses of bloodstream and non-bloodstream isolates, it reveals distinct phenotypic and resistance profiles, high genetic diversity, and potential nosocomial transmission in COVID-19 patients. These findings underscore the importance of recognizing population-specific traits in C. krusei, which may guide tailored antifungal strategies and strengthen infection control measures, especially for vulnerable groups such as ICU and immunocompromised patients.
Insights
Candida krusei bloodstream infections show distinct traits compared to other sources. Understanding these differences in antifungal susceptibility and genetics can improve treatment and control for vulnerable patients.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Candida krusei is an opportunistic pathogen known for intrinsic fluconazole resistance.
- Bloodstream infections (BSIs) caused by C. krusei are linked to high mortality and limited treatment choices.
- Understanding C. krusei pathogenicity and invasive potential is crucial for effective management.
Purpose of the Study:
- To analyze and compare Candida krusei isolates from bloodstream infections (BSIs) and non-blood sources.
- To investigate phenotypic differences, antifungal susceptibility, and genetic diversity.
- To identify factors contributing to C. krusei pathogenicity and inform therapeutic strategies.
Main Methods:
- Biochemical profiling using VITEK 2 YST ID Card.
- Antifungal susceptibility testing (CLSI broth microdilution, Sensititre YeastOne).
- Microsatellite genotyping at eight loci.
Main Results:
- Significant difference in TyrA reaction between BSI and non-blood isolates (P < 0.05).
- BSI isolates showed greater susceptibility to echinocandins and azoles than non-blood isolates.
- High genetic diversity observed; cluster of respiratory isolates from COVID-19 patients suggests potential nosocomial transmission.
Conclusions:
- Integration of phenotypic, susceptibility, and genotypic data reveals distinct profiles of C. krusei from different infection sources.
- Findings highlight potential virulence traits and epidemiological patterns, including nosocomial transmission in COVID-19 patients.
- Results support developing tailored antifungal therapies and enhanced infection control for high-risk populations like ICU and COVID-19 patients.
