Prevalence and molecular basis of resistance to echinocandins among clinical Candida glabrata isolates in Guangdong province, China.

BACKGROUND

Infections caused by Candida glabrata have raised increasing concerns, particularly due to the increasing resistance to echinocandins.

OBJECTIVES

This study investigated echinocandins susceptibility trends in C. glabrata isolates and explored the mechanisms driving resistance.

METHODS

We analyzed 418 strains of C. glabrata derived from hospitalized patients. Phenotypic resistance was assessed, and genotypic analysis was performed to identify mutations in the hotspot-1 and hotspot-2 regions of the FKS1 and FKS2 genes. Additionally, genotyping was conducted using multilocus sequence typing (MLST).

RESULTS

The resistance rates to caspofungin, anidulafungin, and micafungin were 5.0%, 3.8%, and 4.0%, respectively, while fluconazole resistance was observed in 9.6% of the strains. Notably, 1.0% of the strains demonstrated resistance to both fluconazole and echinocandins. Mutations in the FKS genes were identified in 11 strains, predominantly in the FKS2-HS1 region. The most prevalent mutation was the F659 deletion (54.54%, 6/11), followed by S663F (18.18%, 2/11). Other mutations, including F659S, F659Y, and S663P, were also detected. These 11 mutated strains were classified into six distinct sequence types (STs), with ST208 being the most prevalent.

CONCLUSION

The resistance rate of C. glabrata to echinocandins has been increasing annually in Guangdong province. Echinocandin resistance is associated with mutations in the FKS2 gene.