Novel effect of voriconazole on conidiation of Aspergillus species

Neeraja L. Varanasi, Inthumathi Baskaran, George J. Alangaden, Pranatharthi H. Chandrasekar, Elias Kurian Manavathu

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Our previous studies of Aspergillus fumigatus showed that colonies that grew in the presence of voriconazole (VCZ) were characteristically white without pigmentation. We therefore investigated the effect of various triazoles on conidiation and pigmentation in four commonly isolated Aspergillus species and the results were compared with those obtained for polyene and echinocandin classes of antifungal drugs. Aspergillus cultures were grown on Sabouraud dextrose agar containing subinhibitory concentrations of the antifungal drugs; fungal colonies that grew in the presence of drug were examined microscopically for conidiation and the number of conidia per fungal colony was determined by haemocytometry. Voriconazole at 0.125-0.5mg/l inhibited conidiation in A. fumigatus, Aspergillus flavus, Aspergillus niger and Aspergillus nidulans producing white colonies. The effect of voriconazole was concentration dependent and greater than 99% inhibition of conidiation was obtained in A. flavus at 0.5mg/l. When the white colonies were subcultured on drug-free medium, they readily produced conidia and pigmentation indicating that the effect is reversible. Other triazoles such as itraconazole (ITZ) and posaconazole (PCZ) were poor inhibitors of conidiation. On the other hand, ravuconazole (RCZ) with structural similarity to voriconazole inhibited conidiation in A. fumigatus and A. flavus, but not in A. niger and A. nidulans. Amphotericin B (AMB), nystatin (NYS), caspofungin (CFG) and micafungin (MFG) showed no effect on conidiation. Varying ability among the triazoles to inhibit conidiation in Aspergillus species suggests that the mechanism of action may be unrelated to the well-known inhibition of P450-dependent 14α-sterol demethylase, and perhaps is due to direct or indirect effect on the formation of conidia.

Original languageEnglish (US)
Pages (from-to)72-79
Number of pages8
JournalInternational Journal of Antimicrobial Agents
Volume23
Issue number1
DOIs
StatePublished - Jan 1 2004

Fingerprint

Aspergillus
Aspergillus flavus
Triazoles
Aspergillus fumigatus
Fungal Spores
Pigmentation
Aspergillus nidulans
Aspergillus niger
caspofungin
Pharmaceutical Preparations
Sterol 14-Demethylase
Echinocandins
Polyenes
Nystatin
Itraconazole
Amphotericin B
Agar
Glucose
Voriconazole

Keywords

  • Antifungal drugs
  • Aspergillus
  • Conidiation inhibition
  • Lanosterol demethylase
  • Voriconazole

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)

Cite this

Varanasi, N. L., Baskaran, I., Alangaden, G. J., Chandrasekar, P. H., & Manavathu, E. K. (2004). Novel effect of voriconazole on conidiation of Aspergillus species. International Journal of Antimicrobial Agents, 23(1), 72-79. https://doi.org/10.1016/j.ijantimicag.2003.05.011

Novel effect of voriconazole on conidiation of Aspergillus species. / Varanasi, Neeraja L.; Baskaran, Inthumathi; Alangaden, George J.; Chandrasekar, Pranatharthi H.; Manavathu, Elias Kurian.

In: International Journal of Antimicrobial Agents, Vol. 23, No. 1, 01.01.2004, p. 72-79.

Research output: Contribution to journalArticle

Varanasi, NL, Baskaran, I, Alangaden, GJ, Chandrasekar, PH & Manavathu, EK 2004, 'Novel effect of voriconazole on conidiation of Aspergillus species', International Journal of Antimicrobial Agents, vol. 23, no. 1, pp. 72-79. https://doi.org/10.1016/j.ijantimicag.2003.05.011
Varanasi, Neeraja L. ; Baskaran, Inthumathi ; Alangaden, George J. ; Chandrasekar, Pranatharthi H. ; Manavathu, Elias Kurian. / Novel effect of voriconazole on conidiation of Aspergillus species. In: International Journal of Antimicrobial Agents. 2004 ; Vol. 23, No. 1. pp. 72-79.
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