Helen R. Buckley

An amino acid liquid synthetic medium for the development of mycelial and yeast forms of Candida albicans

A chemically defined medium composed of 6 amino acids, biotin, inorganic salts and glucose for the growth of yeast and mycelial phases of Candida albicans at 25 degrees C and 37 degrees of C respectively was developed based on the aminopeptidase(s) profile of the fungus. This medium has proved successful in maintaining the growth characteristics of both phases during serial transfers. The relative pathogenicity, virulence, invasiveness and immunogenicity of the yeast and mycelial phases are discussed.

Detection of Circulating Candida Enolase by Immunoassay in Patients with Cancer and Invasive Candidiasis

BACKGROUND Invasive candidiasis is a major nosocomial infection that is difficult to diagnose. Few biochemically defined markers of invasive candidiasis are known. Initial findings suggested that the presence of candida enolase in the blood may be a novel marker for invasive candidiasis. METHODS We tested 170 patients at high risk for invasive candidiasis for candida enolase antigenemia. All the patients had cancer and neutropenia. We detected antigen using a double-sandwich liposomal immunoassay for candida enolase in serially collected serum samples. Invasive candidiasis was proved by finding candida species in deep nonmucosal tissue, blood cultures, or both. Antigen testing was performed with the investigator blinded to tissue or culture diagnosis. RESULTS Among 24 patients with proved invasive candidiasis, 149 serum samples were tested for enolase antigenemia; 80 were positive and 69 negative (sensitivity per sample, 54 percent). Multiple sampling improved the detection of antigenemia, which was found in 11 of 13 proved cases of deep tissue infection (85 percent) and in 7 of 11 proved cases of fungemia (64 percent). Specificity was 96 percent as measured against control groups including patients with mucosal colonization, bacteremia, and other deep mycoses. Antigenemia was detected in the absence of fungemia in 5 cases of deep tissue candidiasis, but was not detected in 6 cases of fungemia alone. CONCLUSIONS Candida enolase antigenemia is a novel marker for invasive candidiasis. It may be a useful indicator of deep infection in patients with cancer and neutropenia and may complement the diagnostic usefulness of blood cultures.

Chronic fungal vaginitis: The value of cultures

OBJECTIVE Our purpose was to examine the importance of fungal cultures in evaluating patients with symptoms of chronic vaginitis by assessing the relative contribution of various yeast species and by comparing infections caused by Candida albicans with those caused by other species. STUDY DESIGN A prospective observational study of patients referred with chronic vaginal symptoms was undertaken. In addition to a standard evaluation of symptoms, cultures for yeast were performed on modified Sabouraud agar plates. RESULTS Seventy-seven isolates were obtained from 74 patients. A total of 68% were Candida albicans; 32% were other species. The clinical syndromes caused by non-Candida albicans isolates were indistinguishable from Candida albicans infections. Fluconazole gave a short-term mycologic cure in all Candida albicans but only 25% of non-Candida albicans cases (p < 0.001). In non-Candida albicans infections, boric acid suppositories achieved the best mycologic cure rate (85%). CONCLUSION Because non-Candida albicans species are responsible for a significant number of chronic fungal vaginal infections and are more resistant to therapy with fluconazole, fungal cultures are a valuable aid in confirming the diagnosis and selecting appropriate therapy.

Clinical features and treatment of Malassezia folliculitis with fluconazole in orthotopic heart transplant recipients

Orthotopic heart transplant recipients need immunosuppressive treatment and are at an increased risk for opportunistic infections such as Malassezia folliculitis. During a 4-month period (July to October 1990), 11 such cases were identified and treated; all were male with mean age of 43+/-9 years and on standard triple immunosuppressive therapy. Skin scrapings in potassium hydroxide (KOH) preparation with microscopy and/or culture identified either Malassezia furfur or Malassezia pachydermatis as the etiologic agent. A treatment with topical preparation (clotrimazole 1% and selenium sulfide lotion) was effective in 6 patients, whereas the rest received systemic fluconazole treatment with satisfactory outcome; all lesions were resolved within 3 weeks. Fluconazole appears to be an effective agent with excellent therapeutic outcome when administered for 3 weeks.

An antifungal compound from Solanum nigrescens

The antifungal activity of Solanum nigrescens extracts has been traced to the presence of a spirostanol glycoside, cantalasaponin-3.

Differential Protein Synthesis in Candida albicans during Blastospore Formation at 24.5 C and during Germ Tube Formation at 37 C

SUMMARY: To identify proteins synthesized during blastospore to germ tube transformation in Candida albicans, membrane and cytoplasmic protein fractions labelled with 14C were analysed by SDS-PAGE and autoradiography. Four cytoplasmic proteins were detected in pulse-labelled lysates prepared from cells forming blastospores and germ tubes at 37 °C, but not in pulse-labelled lysates prepared from cells forming blastospores at 24.5 °C. Three proteins detectable in 24.5 °C lysates were diminished in 37 °C lysates.

Effects of culture density on the kinetics of germ tube formation in Candida albicans

The relationship between culture density or phase of growth at 24.5 degrees C and the ability of Candida albicans to form germ tubes when shifted to 37 degrees C was investigated. Evidence is presented demonstrating germ tube production from liquid synthetic medium cultures at all phases of growth. Previous studies reported that only cells from stationary phase cultures were competent to form germ tubes. Comparisons between exponential and stationary phase cultures indicate more rapid and more synchronous germ tube production from cells growing in the exponential phase.

Isolation of a gene encoding a putative polyamine transporter from Candida albicans, GPT1

A gene encoding a transport protein from the pathogenic yeast, Candida albicans, has been isolated during a complementation experiment utilizing an ornithine decarboxylase‐negative (spe1Δ) strain of Saccharomyces cerevisiae. This gene restores γ‐aminobutyric acid (GABA) transport to a GABA transport‐negative mutant of S. cerevisiae and encodes a protein which putatively allows transport of one or more of the polyamines. We have assigned the name GPT1 (GABA/polyamine transporter) to this gene. The GenBank Accession No. for this gene is AF080132. Copyright

Evaluation of the RapID yeast plus system for the identification of yeast

We evaluated the RapID Yeast Plus System using 117 fresh and frozen clinical yeast isolates. The Uni-Yeast-Tek System was used to establish the correct identification. The Vitek System was used as the arbiter for any discrepant results, along with morphology. Of 117 isolates tested, the RapID Yeast Plus System identified 96.6% correctly. The RapID Yeast Plus System is an accurate and reliable alternative to other commonly used yeast identification systems.

Isolation and sequence of the gene encoding ornithine decarboxylase, SPE1, from Candida albicans by complementation of a spe1Δ ctrain of Saccharomyces cerevisiae

The gene encoding ornithine decarboxylase, SPE1, from the pathogenic yeast Candida albicans has been isolated by complementation of an ornithine decarboxylase‐negative (spe1Δ) strain of Saccharomyces cerevisiae. Four transformants, three of which contain plasmids with the SPE1 gene, were isolated by selection on polyamine‐free medium. The C. albicans ornithine decarboxylase (ODC) showed high homology with other eukaryotic ODCs at both the amino acid and nucleic acid levels. The GenBank accession number for this gene is U85005.