Comparison of two different methods for the investigation of in vitro susceptibilities of planktonic and biofilm forming Candida species to antifungal agents

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Mikrobiyoloji bulteni

Mikrobiyol.Bul.

Oct

619

631

JID: 7503830; 0 (Antifungal Agents); ppublish

Turkey

0374-9096; 0374-9096

PMID: 21063974

tur

Comparative Study; English Abstract; Journal Article; IM

Unknown(0)

21063974

Microdilution method that determines the minimum inhibitory concentrations (MIC) of antifungal agents against Candida spp. is still the only method used in laboratories for both biofilm and planktonic forms. However, it was determined in several studies that there were susceptibility differences between the biofilm and planktonic forms of the same microorganism. The aims of this study were the determination of in vitro susceptibilities of planktonic and biofilm forms of Candida strains against antifungal agents, the comparison of the data obtained from planktonic and biofilm forms and the evaluation of two different methods used for the detection of susceptibilities of biofilm forms. Candida albicans ATCC 10231, Candida parapsilosis ATCC 90028 and Candida krusei ATCC 6258 were used as reference strains together with clinical isolates of one of each C.albicans, C.parapsilosis and Candida tropicalis. Microdilution method was used to determine the susceptibilities of planktonic forms of the strains according to CLSI M27-A3 standards, and MIC values of fluconazole, itraconazole, flucytosine, amphotericin B and nystatin were determined. For the detection of antifungal susceptibilities of Candida spp. biofilm forms, Calgary biofilm method (CBM) and BioTimer assay (BTA) were used, and minimum biofilm eradication concentration (MBEC) and minimum biofilm inhibition concentration (MBIC) values of the same antifungals were determined. The difference between MIC and CBM-MBEC, CBM-MBEC and BTA-MBEC, CBM-MBEC and BTAMBIC values were found statistically significant (p 0.05) for the other antifungal agents. These findings supported that antifungal susceptibilities of biofilm forming Candida strains should also be investigated. However, MBEC and MBIC of the antifungal agents should not always be expected to be higher than the MIC values since the mechanism of action of the specific antifungal agents and the first inoculum concentration of the microorganisms might differ.

Antifungal Agents/pharmacology, Biofilms/drug effects, Candida/drug effects/physiology, Humans, Microbial Sensitivity Tests/methods, Plankton/drug effects

Kaynak Onurdag,F., Ozgen,S., Abbasoglu,U., Gurcan,I. S.

Candida turlerinin biyofilm olusturan ve planktonik formlarinin antifungal ajanlara karsi in vitro duyarliliklarinin arastirilmasinda iki farkli yontemin karsilastirilmasi

Gazi Universitesi Eczacilik Fakultesi, Farmasotik Mikrobiyoloji Anabilim Dali, Ankara, Turkiye. fkaynak@gmail.com

http://vp9py7xf3h.search.serialssolutions.com/?charset=utf-8&pmid=21063974

2010