Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants.

Autor: Bordallo-Cardona MÁ; Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain., Sánchez-Carrillo C; Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain., Bouza E; Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.; CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain.; Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain., Muñoz P; Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.; CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain.; Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain., Escribano P; Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain., Guinea J; Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain jguineaortega@yahoo.es.; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.; CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain.; Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.
Jazyk: angličtina
Zdroj: Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2019 Feb 26; Vol. 63 (3). Date of Electronic Publication: 2019 Feb 26 (Print Publication: 2019).
DOI: 10.1128/AAC.02004-18
Abstrakt: Infections caused by the coexistence of Candida glabrata echinocandin-resistant and echinocandin-susceptible cells may be possible, and the detection of FKS mutants when the proportions of FKS mutants are underrepresented poses a problem. We assessed the role of EUCAST and methods directly performed on positive blood cultures-Etest (ET DIR ) and anidulafungin-containing agar plate assays-for detecting resistance in C. glabrata isolates containing different amounts of echinocandin-susceptible and -resistant Candida glabrata isolates. We studied 10 pairs of C. glabrata isolates involving parental echinocandin-susceptible isolates and isogenic echinocandin-resistant FKS mutant isolates. Three inocula per pair (1 ×   10 3 to 5   ×   10 3 , 1 ×   10 2 to 5   ×   10 2 , and 10 to 50 CFU/ml) spanning suspensions with different amounts of susceptible/resistant isolates (9/1, 5/5, and 1/9 proportions for each the three inocula) were prepared. The suspensions were spiked in Bactec bottles and incubated until they were positive, and the three methods were compared. The EUCAST method showed echinocandin resistance when the bottles were spiked with susceptible/resistant isolates at 5/5 and 1/9 proportions; the results for the suspensions with a 9/1 proportion of susceptible/resistant isolates were susceptible for three pairs. We observed with the ET DIR resistance to both echinocandins in all pairs (resistance to micafungin and anidulafungin; MICs, ≥0.064   mg/liter and ≥0.125   mg/liter, respectively) and a double ring of growth inhibition in two pairs. The anidulafungin-containing plates showed fungal growth in the 90 spiked blood cultures at 48 h. Testing of echinocandin susceptibility with the ET DIR directly on the positive blood culture bottles is a reliable and rapid method to detect echinocandin resistance in C. glabrata On the other hand, resistance can be missed with the EUCAST method when resistant isolates are underrepresented.
(Copyright © 2019 American Society for Microbiology.)
Databáze: MEDLINE
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