1. In vitro susceptibility testing to caspofungin and anidulafungin of Candida spp. isolated from blood cultures in 7 Belgian hospitals C. Van Laer 1*2,2 K. Lagrou 2, P. Vandecandelaere 3*, AM. Van den Abeele 4*, J. Frans 5*, R. Cartuyvels 6*, E. Oris 7*, H. De Beenhouwer 1*, K. Van Vaerenbergh 1*, A. Boel 1* 1 OLV Hospital, Aalst, 2 University Hospitals Leuven, Leuven, 3 Jan Yperman Hospital, Ieper, 4 Sint-Lucas Hospital, Ghent, 5 Imelda Hospital, Bonheiden, 6 Jessa Hospital, Hasselt, 7 Hospital Zuid-Oost Limburg, Genk; Belgium. *On behalf of the BILULU study group. In vitro susceptibility testing to caspofungin and anidulafungin of Candida spp. isolated from blood cultures in 7 Belgian hospitals C. Van Laer 1*2,2 K. Lagrou 2, P. Vandecandelaere 3*, AM. Van den Abeele 4*, J. Frans 5*, R. Cartuyvels 6*, E. Oris 7*, H. De Beenhouwer 1*, K. Van Vaerenbergh 1*, A. Boel 1* 1 OLV Hospital, Aalst, 2 University Hospitals Leuven, Leuven, 3 Jan Yperman Hospital, Ieper, 4 Sint-Lucas Hospital, Ghent, 5 Imelda Hospital, Bonheiden, 6 Jessa Hospital, Hasselt, 7 Hospital Zuid-Oost Limburg, Genk; Belgium. *On behalf of the BILULU study group. Candida spp. isolated from blood cultures during a 9 month period in 7 Belgian hospitals were tested against 2 echinocandins, anidulafungin and caspofungin. Results were compared with previously described susceptibility data (1). From December 2010 till August 2011, all Candida spp. isolated from blood cultures (n=104, no duplicates) were collected in 7 Belgian hospitals: Onze Lieve Vrouw Hospital, Aalst (n=10) University Hospitals Leuven, Leuven (n=55) Jan Yperman Hospital, Ieper (n=8) Sint-Lucas Hospital, Ghent (n=5) Imelda Hospital, Bonheiden (n=6) Jessa Hospital, Hasselt (n=10) Hospital Zuid-Oost Limburg, Genk (n=10) All isolates were identified to species level by ITS2 fragment length analysis. Susceptibility testing was performed in one centre on RPMI agar (AES Chemunex Laboratoire, Bruz Cedex, France) with E-test (Etest® BioMérieux, Marcy-l’Etoile, France) for caspofungin and anidulafungin. Results were interpreted following CLSI M27-S3 guidelines and ATCC 22019 C. parapsilosis and ATCC 6258 C. krusei were used as QC (2). Overall MIC values (in µg/mL) for caspofungin ranged from 0,008 to 1,5 (MIC 90 : 0,25) and for anidulafungin from 0,002 to 4 (MIC 90 : 0,016), fig 2. For C. albicans MIC values for caspofungin ranged from 0,008 to 0,32 (MIC 90 : 0,125) and for anidulafungin from 0,002 to 0,008 (MIC 90 : 0,004). MIC values for all C. glabrata strains were in the same ranges as for C. albicans: 0,008-0,25 (MIC 90 : 0,19) for caspofungin and 0,002-0,016 (MIC 90 : 0,012) for anidulafungin (fig 2). Other Candida strains (C. tropicalis, C. kefyr and C. dubliniensis) had low MIC values for caspofungin and anidulafungin: 0,016-0,6 and 0,004-0,016 respectively. The only Candida spp. with higher MIC values for the tested echinocandins was C. parapsilosis with MIC values from 0,25 to 1,5 (MIC 90 : 1) for caspofungin and from 1 to 4 (MIC 90 : 3) for anidulafungin, fig 2. Fig 2: MIC distributions for anidulafungin and caspofungin for all Candida isolates, C. albicans, C. glabrata and C. tropicalis Introduction Materials and methods 1.In accordance with previously published data, we obtained very low MIC values for echinocandins for this Belgian C. albicans, C. glabrata, C. krusei and C. kefyr isolates and higher MIC values for C. parapsilosis (1). 2.We remark that MIC values were 3 to 4 dilutions lower for anidulafungin than for caspofungin. This observation was earlier described by M. Arendrup when susceptibility testing was performed with E-test, fig 3 (3). Conclusions Results (1)Pfaller M. et al, Wild-Type MIC Distributions and Epidemiological Cutoff Values for the Echinocandins and Candida spp., JCM 2010, 48(1):52-56 (2)CLSI Reference Method for Broth Dilution Antifungal Susceptibility Testing of Yeasts; 3th Informational Supplement, M27-S3, vol 28 n°15 (3)M. Arendrup, Susceptibility testing of Fungi, Antwerp 2011, Fungal infections and frustrations across the border Acknowledgement: The authors thank Pfizer for the supply of materials for susceptibility testing: E-test and RPMI agars. contact: christine.1.vanlaer@uzleuven.be Species distribution for the 104 Candida spp. isolates was: 56 Candida albicans, 35 C. glabrata, 8 C. parapsilosis, 2 C. tropicalis, 1 C. krusei, 1 C. kefyr and 1 C. dubliniensis (fig 1). Fig 1: Species distribution of 104 Candida spp. isolates References Fig 3: MIC determined with E-test is different of ref. method (3, with permission of Dr. M. Arendrup) C. albicans This study showed a difference in MIC values for anidulafungin and caspofungin, with exception of C. parapsilosis: MIC values were 3 to 4 dilution steps lower for anidulafungin than for caspofungin. These findings were described by M. Arendrup when susceptibility was determined with E-test, instead of using CLSI reference method, fig 3 (3).