# Incidence of azole resistance among clinical isolates of Candida parapsilosis: Results from the French nationwide multicenter prospective study “ReCap” 2022-2024

## TL;DR

This study reports on the spread of fluconazole-resistant Candida parapsilosis in France, finding high resistance rates and two clusters in the Paris area.

## Contribution

The study provides the first nationwide assessment of azole resistance in C. parapsilosis in France and identifies circulating resistant clusters.

## Key findings

- 15.1% of C. parapsilosis isolates were resistant to fluconazole, affecting 10% of patients.
- Two fluconazole-resistant clusters were identified in the Paris area through genotyping.
- 62.9% of fluconazole-resistant isolates also showed resistance to voriconazole.

## Abstract

Fluconazole-resistant isolates of Candida parapsilosis have emerged worldwide in recent years.

Our objectives were to get an overview of the French epidemiology, to determine the incidence of azole resistance and to assess the genetic relationship between isolates.

We initiated a prospective national multicenter study (ReCap - Resistance of Candida parapsilosis to azole drugs). All C. parapsilosis isolates routinely identified in 15 French hospital mycology laboratories were included over a period of 6 to 20 months (depending on the center), regardless of the type of specimen and hospitalization unit. Isolates were tested for fluconazole susceptibility using a gradient diffusion method. Non-susceptible isolates (MIC ≥4 mg/L) and a random selection of susceptible isolates were subjected to further analysis (MICs determination by EUCAST method and microsatellite genotyping).

Between May 2022 and February 2024, a total of 2,602 isolates were collected from 1,830 patients. Among these, 392 isolates (15.1%) from 184 patients (10%) were found to be resistant (MIC >4 mg/L). Percentage of patients colonized or infected by a resistant isolate ranged from 0 to 54.4% across centers. Genotyping analysis performed on 1,320 isolates showed high diversity among susceptible isolates and indicated that two fluconazole-resistant clusters are circulating in different hospitals of the Paris area. Cross-resistance occurred frequently with voriconazole resistance observed in 62.9% (73/116) of fluconazole-resistant isolates.

In France, the frequency of resistance to fluconazole reaches 10% of patients harboring C. parapsilosis, with very significant differences between regions. The Paris area is affected by two epidemic clusters involving many patients.