# P-1942. Candidozyma auris Susceptibility from Michigan Hospitals to Rezafungin and Nine Other Antifungal Agents

## TL;DR

This study compares the susceptibility of Candida auris isolates from Michigan hospitals to antifungal drugs, finding regional differences in drug response.

## Contribution

The study provides new regional susceptibility data for C. auris isolates from Michigan compared to isolates from other locations.

## Key findings

- Michigan isolates showed higher susceptibility to amphotericin B compared to isolates from other regions.
- Azole antifungals were less effective against Michigan isolates than reference isolates.
- Echinocandins showed excellent activity against all isolates regardless of geographic origin.

## Abstract

C. auris has been reported as a multidrug resistant pathogen with variability of susceptibility to antifungal agents. Multiple clades have been identified with different geographic penetrance. In view of the severity of illness and mortality associated with C. auris infections, optimal therapy needs additional guidance in terms of in vitro data and identification of new antifungal agents. Our study evaluated in vitro activity of ten antifungal agents against 67 isolates from Michigan and compared them to isolates from sites outside of Michigan.C. auris MIC

C. auris MIC

C. auris isolates were processed on sabouraud dextrose agar at 35°C for 24 hours and identification was performed by MALDI-TOF-MS or by Vietk-2 yeast card. Identity was confirmed by CHROMagar Candida Plus. The antifungals tested were amphotericin B, anidulafungin, caspofungin, fluconazole, isavuconazole, itraconazole, micafungin, posaconazole, rezafungin and voriconazole.

Broth microdilution antifungal susceptibility testing (AST) was performed according to Clinical Laboratory Standards and Antifungal Susceptibility Testing of Yeasts. AST testing was performed using Sensititre™ YeastOne™ AST Plate.

Percent sensitivity was determined by tentative breakpoints from the CDC C. auris breakpoint guidelines, CLSI M23M44 Ed3, EUCAST antifungal breakpoints v 11.0 and estimated breakpoints from published reports.

In vitro testing results are summarized in table 1. The amphotericin B susceptibility was higher for Michigan isolates than those from sites outside of Michigan (98.5% vs 81.8%) and each of the azoles demonstrated less activity against the Michigan hospital isolates vs the reference isolates. All the echinocandins demonstrated excellent activity against strains whether they were present in Michigan or outside of Michigan.

C. auris demonstrated differences in susceptibility from Michigan hospitals by being more susceptible to Amphotericin B and less susceptible to the azoles than the isolates from other areas of the country. All isolates were susceptible to the echinocandins tested. Regional susceptibility testing of C. auris should be considered because of variability among clades and therapeutic options that clinicians need to have when treating serious C. auris infections.

All Authors: No reported disclosures