Abstract
We have compared multilocus sequence typing (MLST) and fluconazole susceptibility profiles of Candida glabrata bloodstream isolates obtained during active, population-based surveillance to those obtained from non-sterile sites of individuals with no evidence of fungal disease (i.e., non-invasive isolates) in the same US city during an overlapping time period. In each of the two populations, different proportions of the same six major sequence types (STs) encompassed 82% of the isolates. One ST was more prevalent in the candidemia population and two other STs were more prevalent in the non-invasive population, but the overall allelic frequencies within the groups suggested little, if any, genotypic diversity between them. Fluconazole susceptibility profiles of isolates from the patients in the two groups were not significantly different and were not associated with a particular sequence type. Our results support the hypothesis that C. glabrata strains causing bloodstream infections are genetically indistinguishable from those normally residing in/on the host, suggesting that relative pathogenicity may be closely tied to commensalism.
Acknowledgements
The authors would like to acknowledge the significant contributions of the following members of the Atlanta CDC Candidemia Surveillance Group: Angela Ahlquist, Monica Farley, Betsy Siegel, Kizee Etienne, Eszter Deak, Joyce Peterson, Naureen Iqbal, Lauren Smith and Tom Chiller. We thank the staff of all the institutions that contributed isolates to this study. We would like to thank Dr Anne Whitney and the members of the DFBMD core sequencing laboratory for their technical assistance and Dr Mary Brandt for her helpful comments. We would also like to thank Yaffa Adiri for her archiving and retrieval of the non-invasive isolates.
Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.
Declaration of interest: The authors report no conflicts of interest, except for GML who received funding from Merck. The authors alone are responsible for the content and writing of the paper.
This paper was first published online on Early Online on 21 July 2011.