The Use of a DNA Probe for Epidemiological Studies of Candidiasis in Immunocompromised Hosts

Fox, Barry C.; Mobley, Harry L. T.; Wade, James C.

doi:10.1093/infdis/159.3.488

Cited by 92 publications

(60 citation statements)

References 28 publications

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“…The species-specific probes CT13.8 for C. tropicalis, 27A for C. albicans and CK13 for C. krusei were used to determine strain relatedness, and where possible, DNA fingerprints. 27A was cloned by S. Scherer and D. A. Stevens and has been described extensively (Fox et al, 1989;Scherer & Stevens, 1988). CK13 was cloned using the folowing protocol.…”

Section: Methodsmentioning

confidence: 99%

The molecular analysis of synonymy among medically important yeasts within the genus Candida

Wickes

Hicks

Merz

et al. 1992

Journal of General Microbiology

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Three sets of medically important yeasts, Candida albicans, C. tropicalis, and C. krusei, were compared with their putative synonyms (C. langeronii and C. claussenii, C. paratropicalis, and Itssatchenkia orientalis, respectively) to determine if these synonyms are genetically distinguishable from each other. Pulsed-field electrophoresis and hybridization to species-specific probes were used to accomplish this goal. The species-specific probes for C. albkans and C. tropkafis have been previously described (27A and (3'13.8, respectively) whereas the probe for C. krusei (CK3) was cloned in this study. No distinguishing characteristics between synonyms were identified, thus supporting the current taxonomic treatment of these organisms.

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Section: Methodsmentioning

confidence: 99%

The molecular analysis of synonymy among medically important yeasts within the genus Candida

Wickes

Hicks

Merz

et al. 1992

Journal of General Microbiology

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“…The probe was C. albicans-specific, with several copies dispersed throughout the genome. When total cellular DNA from the C. albicans isolates was digested and hybridized with the probe, the resulting multiple fragments detected following autoradiography constituted molecular 'fingerprint' patterns which could be used to distinguish between different strains (Scherer & Stevens, 1988;Fox et al, 1989). The molecular fingerprints of all nine isolates were clearly different from each other, whereas the fingerprints of spontaneous variant colonies of the same clinical isolate were in each case indistinguishable (data not shown).…”

Section: P J Gallagher and Othersmentioning

confidence: 98%

Reduced azole susceptibility of oral isolates of Candida albicans from HIV-positive patients and a derivative exhibiting colony morphology variation

Gallagher

Bennett

Henman

et al. 1992

Journal of General Microbiology

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Approximately 50 % (15/28) of a selection of oral isolates of Candida albicuns from separate individuals infected with the human immunodeficiency virus (HIV) exhibited low susceptibility to ketoconazole as determined by hyphal elongation assessment. Nine of these isolates exhibited colony morphology variation or switching at 37 "C, of which six expressed low ketoconazole susceptibility. To determine whether colony morphology variation could give rise to derivatives with reduced azole susceptibility, several high-frequency switching variants of three HIVpatient isolates were recovered and assessed. All but one of the variants expressed similar azole susceptibility profiles to their respective parental strains. However, the C. albicans derivative 132ACR expressed significantly reduced susceptibility to ketoconazole in comparison to its parental strain 132A. In whole cells, on the basis of total growth the switched derivative 132ACR was markedly less susceptible than its parental isolate 132A to ketoconazole at 10 p~. A much smaller difference was observed with fluconazole at 10 PM, with the switched derivative 132ACR exhibiting a threefold lower susceptibility compared with the parental isolate 132A. The incorporation of [14C]acetate in control and azole-treated cells of both organisms was higher for the parental strain. When cell lysates of strain 132A and its derivative 132ACR were incubated with 114C]mevalonic acid and ketoconazole, the IC,, for 14C-label incorporation into 63-4 demethyl sterols was fivefold higher for lysates of the . switched derivative 132ACR compared with those of the parental strain 132A. With fluconazole the IC5,, value for the derivative 132ACR was 25-fold higher than for strain 132A. The 14-sterol demethylase of the switched derivative 132ACR was possibly less sensitive to azole inhibition than that of the enzyme of strain 132A. These studies indicated that colony morphology variation in vifro can generate derivatives with stable, reduced azole susceptibility without prior exposure to azoles.

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“…The extent of variation detected with some of the DNA probes may be as extensive as fingerprinting. Limitations include the need for specialized equipment which may not be available in all clinical laboratories and the need for radiolabeled probes (although development of nonradiolabeled probes are now available, such as the biotinylated probe [20]). In addition, definitive comparisons may require strains to be studied on the same gel, making analysis of large numbers of strains difficult without a computer data base.…”

Section: Electrophoretic Karyotypingmentioning

confidence: 99%

Candida albicans strain delineation

Merz

1990

Clin Microbiol Rev

118

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Candida albicans is a major opportunistic pathogen causing a wide spectrum of disease in human beings. Methods for strain delineation of this species to assess or predict virulence or to conduct epidemiologic or pathogenetic investigations have been developed. Although factors associated with virulence have been identified, there is no rapid system to quantitate them in a clinical laboratory. Therefore, many typing methods are based on variable phenotypic characteristics within this species including morphotyping, serotyping, antibiogram, resistogram typing, biotyping, biotyping based on commercial carbon assimilation patterns, enzyme profiles, sensitivity to yeast killer toxins, and typing based on protein variability. Phenotypically defined strains generally do not correlate with the pathogenic potential of a strain with the exception of morphotyping. However, these methods can be useful in epidemiologic investigations; for example, they have revealed that most individuals harbor one strain and that infections are frequently due to an endogenous strain. Problems with these methods usually relate to their discriminatory power. When this is maximized, reproducibility (especially between laboratories) suffers. Recently, methods based on differences in DNA structure (genotyping) for strain delineation have been developed, including electrophoretic karyotyping and restriction enzyme fragment length polymorphisms. The development of a computer-assisted data bank and analysis for these genotypic strain delineators will open investigations into the pathogenesis of this infection and permit epidemiologic studies previously not possible with this important human pathogen.

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The Use of a DNA Probe for Epidemiological Studies of Candidiasis in Immunocompromised Hosts

Cited by 92 publications

References 28 publications

The molecular analysis of synonymy among medically important yeasts within the genus Candida

The molecular analysis of synonymy among medically important yeasts within the genus Candida

Reduced azole susceptibility of oral isolates of Candida albicans from HIV-positive patients and a derivative exhibiting colony morphology variation

Candida albicans strain delineation

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