title: Susceptibility of Candida albicans biofilms to caspofungin and anidulafungin is not affected by metabolic activity or biomass production.
abstract: Micafungin is more active against biofilms with high metabolic activity; however, it is unknown whether this observation applies to caspofungin and anidulafungin and whether it is also dependent on the biomass production. We compare the antifungal activity of anidulafungin, caspofungin, and micafungin against preformed Candida albicans biofilms with different degrees of metabolic activity and biomass production from 301 isolates causing fungemia in patients admitted to Gregorio Marañon Hospital (January 2007 to September 2014). Biofilms were classified as having low, moderate, or high metabolic activity according XTT reduction assay or having low, moderate, or high biomass according to crystal violet assay. Echinocandin MICs for planktonic and sessile cells were measured using the EUCAST E.Def 7.2 procedure and XTT reduction assay, respectively. Micafungin showed the highest activity against biofilms classified according to the metabolic activity and biomass production (P < .001). The activity of caspofungin and anidulafungin was not dependent on the metabolic activity of the biofilm or the biomass production. These observations were confirmed by scanning electron microscopy. None of the echinocandins produced major changes in the structure of biofilms with low metabolic activity and biomass production when compared with the untreated biofilms. However, biofilm with high metabolic activity or high biomass production was considerably more susceptible to micafungin; this effect was not shown by caspofungin or anidulafungin.
authors.affiliation: Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Laura Judith
authors.initials: LJ
authors.lastname: Marcos-Zambrano
authors.affiliation: 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.
authors.forename: Pilar
authors.initials: P
authors.lastname: Escribano
authors.affiliation: 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.
authors.forename: Emilio
authors.initials: E
authors.lastname: Bouza
authors.affiliation: 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 jguineaortega@yahoo.es.
authors.forename: Jesús
authors.initials: J
authors.lastname: Guinea
mesh_terms: D000077612:Anidulafungin; D000935:Antifungal Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D018533:Biomass; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D058387:Candidemia / Q000382:microbiology*; D000077336:Caspofungin; D054714:Echinocandins / Q000494:pharmacology*; D005840:Gentian Violet / Q000032:analysis; D006801:Humans; D055666:Lipopeptides / Q000494:pharmacology*; D000077551:Micafungin; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D011174:Portugal; D013194:Staining and Labeling; D013778:Tetrazolium Salts / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D054714:Echinocandins; D055666:Lipopeptides; D013778:Tetrazolium Salts; C059087:2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide; D000077612:Anidulafungin; D000077336:Caspofungin; D005840:Gentian Violet; D000077551:Micafungin
keywords: EUCAST; Echinocandins; biofilm; micafungin