Temperature affects the susceptibility of Cryptococcus neoformans biofilms to antifungal agents

Robin Pettit, Kimberly K. Repp, Kevin C. Hazen

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The fungal opportunist Cryptococcus neoformans forms biofilms in vitro and in vivo. C. neoformans has an unusual ability to grow over a wide range of temperatures, and is one of only two species in the genus able to grow at 37°C. The optimum growth temperature in the laboratory is 30°C, but Clinical and Laboratory Standards Institute (CLSI) planktonic susceptibility testing is performed at 35°C. We investigated whether these growth temperatures affected C. neoformans biofilm formation and drug resistance. Biofilms of 30 strains of C. neoformans were grown at 30°C or 35°C, and antifungal susceptibilities evaluated at 30°C or 35°C using minimum biofilm eradication endpoints. At 35°C, biofilms from 40% of the strains were more susceptible to flucytosine, 30% were more susceptible to nystatin, 27% were more susceptible to amphotericin, and 20% were more susceptible to fluconazole, as compared to 30°C. The reverse, that is an increased susceptibility at 30°C, only occurred with a single strain using nystatin or fluconazole. For the remaining strains, biofilm susceptibility was equivalent at the two temperatures. Biofilm colony forming units (CFU)s, as measured indirectly by 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5- carboxanilide (XTT) reduction, were greater at 35°C than at 30°C for the majority of the strains. Thus, growth temperature does affect C. neoformans biofilm properties, but factors other than relative biofilm CFUs/ml must be involved in the increased drug susceptibility at 35°C.

Original languageEnglish (US)
Pages (from-to)421-426
Number of pages6
JournalMedical Mycology
Volume48
Issue number2
DOIs
StatePublished - Jan 1 2010

Fingerprint

Cryptococcus neoformans
Antifungal Agents
Biofilms
Temperature
Nystatin
Fluconazole
Growth
Flucytosine
Amphotericin B
Drug Resistance
Stem Cells

Keywords

  • Biofilm
  • Cryptococcus neoformans
  • XTT susceptibility

ASJC Scopus subject areas

  • Infectious Diseases

Cite this

Temperature affects the susceptibility of Cryptococcus neoformans biofilms to antifungal agents. / Pettit, Robin; Repp, Kimberly K.; Hazen, Kevin C.

In: Medical Mycology, Vol. 48, No. 2, 01.01.2010, p. 421-426.

Research output: Contribution to journalArticle

Pettit, Robin ; Repp, Kimberly K. ; Hazen, Kevin C. / Temperature affects the susceptibility of Cryptococcus neoformans biofilms to antifungal agents. In: Medical Mycology. 2010 ; Vol. 48, No. 2. pp. 421-426.
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