In-vitro isolation and antifungal susceptibility of amphotericin B-resistant mutants of Aspergillus fumigatus

Elias Kurian Manavathu, George J. Alangaden, Pranatharthi H. Chandrasekar

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Aspergillus fumigatus mutants resistant to amphotericin B were selected in the laboratory following UV irradiation. A total of 18 colonies (frequency 1.8 x 10-7) that grew in the presence of amphotericin B (8 mg/L and 16 mg/L) on peptone yeast extract glucose agar were tested for their susceptibility to amphotericin B, nystatin, azoles, and the echinocandin L-743872. Ten of the 18 isolates showed an eight-fold rise in amphotericin B MIC (4 mg/L) compared with the susceptible parent whereas the remaining isolates showed a 16 to 32-fold rise in amphotericin B MIC (8-16 mg/L). Subculturing of three representatives from each of the groups that had MIC values of 4 mg/L and 8-16 mg/L for six cycles revealed that the resistance trait was stably expressed. All amphotericin B-resistant isolates showed a significant level of cross-resistance to nystatin but not to azoles and L-743872. Kill-curve studies with amphotericin B revealed that the killing of the resistant isolates was significantly less than that of the susceptible parent strain. These results show that amphotericin B-resistant mutants of A. fumigatus can be isolated in the laboratory following a single-step UV-induced mutagenesis and suggest that similar mechanisms could operate in nature for the emergence of resistance in clinical isolates.

Original languageEnglish (US)
Pages (from-to)615-619
Number of pages5
JournalJournal of Antimicrobial Chemotherapy
Volume41
Issue number6
DOIs
StatePublished - Jun 1 1998

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Aspergillus fumigatus
Amphotericin B
caspofungin
Nystatin
Azoles
Echinocandins
Peptones
In Vitro Techniques
Mutagenesis
Agar
Yeasts
Glucose

ASJC Scopus subject areas

  • Pharmacology
  • Microbiology

Cite this

In-vitro isolation and antifungal susceptibility of amphotericin B-resistant mutants of Aspergillus fumigatus. / Manavathu, Elias Kurian; Alangaden, George J.; Chandrasekar, Pranatharthi H.

In: Journal of Antimicrobial Chemotherapy, Vol. 41, No. 6, 01.06.1998, p. 615-619.

Research output: Contribution to journalArticle

Manavathu, Elias Kurian ; Alangaden, George J. ; Chandrasekar, Pranatharthi H. / In-vitro isolation and antifungal susceptibility of amphotericin B-resistant mutants of Aspergillus fumigatus. In: Journal of Antimicrobial Chemotherapy. 1998 ; Vol. 41, No. 6. pp. 615-619.
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