891. Wild-Type (WT) MIC Distributions and Epidemiological Cutoff Values (ECVs) for Selected Triazole and Echinocandin Antifungal Agents for Six Uncommon Species of Candida as Determined by CLSI Broth Microdilution (BMD) Methods
Session: Poster Abstract Session: Antifungal Therapy
Saturday, October 22, 2011
Room: Poster Hall B1
Background: ECVs provide a sensitive means for detecting emerging resistance and they have not been established for less common, clinically important, species such as C. dubliniensis (CD), C. guilliermondii (CGU), C. kefyr (CKF), C. lusitaniae (CL), C. orthopsilosis (COR), and C. pelliculosa (CPL). We determined species-specific ECVs for anidulafungin (ANF), caspofungin (CSF), fluconazole (FLC), posaconazole (PSC), and voriconazole (VRC) versus six species.

Methods: 819 invasive clinical isolates of CD (70 isolates), CGU (198), CKF (112), CL (280), COR (102), and CPL (57) were collected from 2001-2010 worldwide (653 isolates from ARTEMIS and 166 from SENTRY). Susceptibility testing against six compounds using CLSI BMD (24-h incubation) was performed. Isolates were identified by standard biochemical methods and/or molecular sequencing.

Results: The modal MICs (in µg/ml) for ANF,CSF, FLC, PSC, and VRC, respectively, were as follows: for CD ( 0.03, 0.06, 0.25, 0.03, 0.007), CGU ( 2, 0.5, 2, 0.12, 0.06), CKF (0.06, 0.015,  0.25, 0.06, 0.007), CL ( 0.5, 0.25, 0.5, 0.06, 0.007), COR ( 1, 0.12, 0.5, 0.03, 0.015), and CPL (0.015, 0.015, 2, 1, 0.12). The ECVs are summarized in the Table but could not be determined for CPL versus ANF.

 

Conclusion: In the absence of species-specific clinical breakpoints these WT MIC distributions and ECVs will be useful for monitoring the emergence of reduced susceptibility to antifungals among these less common Candida spp. Overall, the activity profiles of both triazoles and two echinocandins were quite favorable against these species. However, activity did vary by drug-species combination.

 

Species

 

ECV (µg/ml: % MIC ≤ ECV

 

ANF

CSF

FLC

PSC

VOR

 

C. dubliniensis

0.12 (95.2)

0.12 (97.8)

0.5 (95.7)

0.12 (98.6)

0.06 (100.0)

 

C. guilliermondii

4 (100.0)

2 (96.0)

8 (95.0)

0.5 (97.5)

0.25 (98.0)

 

C. kefyr

0.25 (98.9)

0.03 (98.0)

1 (99.1)

0.25 (99.1)

0.015 (100.0)

 

C. lusitaneae

2 (100.0)

1 (99.6)

2 (96.1)

0.25 (98.6)

0.03 (96.6)

 

C. orthopsilosis

2 (100.0)

0.5 (100.0)

2 (98.0)

0.25 (97.1)

0.06 (98.0)

 

C. pelliculosa

NDa

0.12 (94.4)

4 (98.2)

2 (98.2)

0.25 (98.2)

 


Subject Category: M. Mycology including clinical and basic studies of fungal infections

Michael A. Pfaller, M.D.1, Daniel J. Diekema2, Shawn A. Messer1, Mariana Castanheira, PhD1 and Ronald Jones, MD1, (1)Microbiology, JMI Laboratories, North Liberty, IA, (2)University of Iowa Carver College of Medicine, Iowa City, IA

Disclosures:

M. A. Pfaller, None

D. J. Diekema, Merck: Grant Investigator, Research grant

S. A. Messer, None

M. Castanheira, None

R. Jones, None

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