Factors Influencing the Susceptibility of Candida albicans to the Polyenoic Antibiotics Nystatin and Amphotericin B

Johnson, B.; White, Rebecca; Williamson, G. M.

doi:10.1099/00221287-104-2-325

Cited by 37 publications

(13 citation statements)

References 15 publications

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“…Most studies have shown minor or no differences in MICs of various antifungal agents tested against yeasts at temperatures ranging from 22 to 37°C (1,3,13,16,17). However, Block et al (2) noted a considerable increase in the susceptibility of Cryptococcus neoformans to flucytosine at 37°C compared with that at 32°C, while precisely the opposite effect of temperature was noted by Johnson et al, working with nystatin (14), and Galgiani et al, working with flucytosine (11), both in tests with Candida spp. An incubation temperature of 35°C has emerged in some recent reports as preferable both to 37°C (5) and to 30°C (23,25) for optimal reader agreement with visual MIC endpoints.…”

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confidence: 80%

“…In all of the reports cited, MIC was the susceptibility endpoint used to determine the effect of temperature, with one exception in which ion efflux in response to nystatin was measured with a K+ electrode (14). However, it has often been stressed that azole-derivative antifungal agents frequently cause partial inhibition of yeast growth at concentrations well below the MIC (1,8,12,19,21).…”

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Effects of temperature on anti-Candida activities of antifungal antibiotics

Odds

1993

Antimicrob Agents Chemother

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The relative growth (percentage of growth relative to control growth) of 767 Candida isolates representing five species was measured in microcultures at 25 and 37°C. In the presence of 10-4 M flucytosine, the distribution of relative yeast growth data indicated that Candida albicans isolates were less susceptible at 25°C than at 37°C, while the opposite was found with 4 x 10-s M amorolfine for most of the isolates tested.Repetition of the experiments at four different temperatures with 99 C. albicans isolates and five antifungal agents confirmed a direct relationship between growth inhibition and increasing temperature from 25 to 40°C with amphotericin B, flucytosine, and terconazole; a strong inverse relationship between inhibition and temperature with amorolfine; and a weak inverse relationship with terbinafine. However, these relationships were not always noted with other Candida spp.: in particular, the growth of C. glabrata and C. parapsilosis isolates tended to be greater at 37°C than at 25°C in the presence of the azole-derivative antifungal agents itraconazole and terconazole. These findings stress the species-specific individuality of yeast susceptibility to azole antifungal agents. The results with C. albicans and amorolfine and terbinafine accord with their known in vivo efficacy in mycoses involving low-temperature superficial sites and poor activity against mycoses involving deep body sites. The data also reinforce the need for control of experimental variables such as temperature in the design of standardized yeast susceptibility tests.

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Effects of temperature on anti-Candida activities of antifungal antibiotics

Odds

1993

Antimicrob Agents Chemother

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“…By contrast the use of chemically complex undefined media such as SAB medium is not recommended (19,28) since undefined components that they may contain might interact with antifungal drugs (13,14,19,26). Furthermore, acidic media such as YNB and SAB, if they were used unbuffered, may inactivate amphotericin B, which is not stable at low pH (16,21).…”

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confidence: 99%

Analysis of Growth Characteristics of Filamentous Fungi in Different Nutrient Media

et al. 2001

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A microbroth kinetic model based on turbidity measurements was developed in order to analyze the growth characteristics of three species of filamentous fungi (Rhizopus microsporus, Aspergillus fumigatus, and Scedosporium prolificans) characterized by different growth rates in five nutrient media (antibiotic medium 3, yeast nitrogen base medium, Sabouraud broth, RPMI 1640 alone, and RPMI 1640 with 2% glucose). In general, five distinct phases in the growth of filamentous fungi could be distinguished, namely, the lag phase, the first transition period, the log phase, the second transition period, and the stationary phase. The growth curves were smooth and were characterized by the presence of long transition periods. Among the different growth phases distinguished, the smallest variability in growth rates among the strains of each species was found during the log phase in all nutrient media. The different growth phases of filamentous fungi were barely distinguishable in RPMI 1640, in which the poorest growth was observed for all fungi even when the medium was supplemented with 2% glucose. R. microsporus and A. fumigatus grew better in Sabouraud and yeast nitrogen base medium than in RPMI 1640, with growth rates three to four times higher. None of the media provided optimal growth of S. prolificans. The germination of Rhizopus spores and Aspergillus and Scedosporium conidia commenced after 2 and 5 h of incubation, respectively. The elongation rates ranged from 39.6 to 26.7, 25.4 to 20.2, and 16.9 to 9.9 m/h for Rhizopus, Aspergillus, and Scedoporium hyphae, respectively. The germination of conidia and spores and the elongation rates of hyphae were enhanced in antibiotic medium 3 and delayed in yeast nitrogen base medium. In conclusion, the growth curves provide a useful tool to gain insight into the growth characteristics of filamentous fungi in different nutrient media and may help to optimize the methodology for antifungal susceptibility testing.

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“…These included 32 strains from a panel selected for their variable susceptibilities to an unrelated antifungal agent, flucytosine (18,21), and 7 strains selected from among clinical isolates from our collection. Another strain was isolated from a patient whose ketoconazole treatment failed (strain K3, also identified by others as KB [9,10,18]). A final C. albicans isolate, strain F662, used previously with strain C17 to evaluate the effect of inoculum size on results obtained with fluconazole (18), was also used for inoculum studies.…”

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In vitro susceptibilities of yeasts to a new antifungal triazole, SCH 39304: effects of test conditions and relation to in vivo efficacy

McIntyre

Galgiani

1989

Antimicrob Agents Chemother

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We used six candidal strains (two Candida albicans and one each of four other species) to study the effects of test conditions on the activity of SCH 39304 compared with that of fluconazole in broth macro-and microdilution assays. Increasing the inoculum from 102 to 105 yeasts per ml raised the MICs for all isolates up to >512-fold. In contrast, results with a 50% turbidimetric endpoint (50% inhibitory concentration; IC,,2) varied no more than twofold. Similar effects were seen with fluconazole, and both drugs were found to have an associated delay in onset of action. Acidity was found to increase both MICs and IC1,2s. Other effects were observed among four synthetic media, but a consistent pattern was not identified. (1-6, 8, 10, 12, 15, 16, 20 [7,18,23]) and one each of C. glabrata (R87), C. tropicalis (F26), C. parapsilosis (3288), and C. lusitaniae * Corresponding author.(ATCC 64125). In addition, 39 isolates of C. albicans were used. These included 32 strains from a panel selected for their variable susceptibilities to an unrelated antifungal agent, flucytosine (18, 21), and 7 strains selected from among clinical isolates from our collection. Another strain was isolated from a patient whose ketoconazole treatment failed (strain K3, also identified by others as KB [9,10,18]). A final C. albicans isolate, strain F662, used previously with strain C17 to evaluate the effect of inoculum size on results obtained with fluconazole (18), was also used for inoculum studies. Locally isolated clinical isolates of C. glabrata (six strains), C. tropicalis (three strains), and C. parapsilosis (three strains) were tested with a single set of conditions. Isolates which had been stored in yeast nitrogen broth (YNB; Difco Laboratories, Detroit, Mich.) with 10% glycerol at -70°C were thawed and maintained on Sabouraud dextrose 3% agar plates (Sab-Dex broth, BBL Microbiology Systems, Cockeysville, Md.; Bacto-Agar, Difco). For studies, subcultures were inoculated into. 20 ml of YNB and incubated at 37°C overnight.Media and buffers. A 2 x concentration of unbuffered SAAMF was prepared as previously described (11), except that cystine was replaced with equimolar amounts of cysteine (14); filter sterilized (cellulose nitrate membrane; pore size, 0.20 pum; Nalge Co., Rochester, N.Y.); and stored at 4°C. This was the medium used for all of the experiments, except when specifically noted otherwise. YNB was prepared as recommended by the manufacturer to a lOx concentration, filter sterilized, and stored at 4°C. Minimal essential medium with Hanks balanced salt solution and RPMI 1640 medium (both from Sigma) were prepared on the day of use as recommended by the manufacturer. YNB and SAAMF were diluted to lx with deionized water, and all media were buffered, adjusted to the appropriate pH, and sterilized by filtration.

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Factors Influencing the Susceptibility of Candida albicans to the Polyenoic Antibiotics Nystatin and Amphotericin B

Cited by 37 publications

References 15 publications

Effects of temperature on anti-Candida activities of antifungal antibiotics

Effects of temperature on anti-Candida activities of antifungal antibiotics

Analysis of Growth Characteristics of Filamentous Fungi in Different Nutrient Media

In vitro susceptibilities of yeasts to a new antifungal triazole, SCH 39304: effects of test conditions and relation to in vivo efficacy

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