Evaluation of SOC for the presumptive identification of Candida albicans and Cryptococcus neoformans

Abstract

SOC, a fungal growth medium composed of Solryth, oxgall, and caffeic acid, was evaluated as a medium to provide rapid, differential identification of Candida albicans and Cryptococcus neoformans. Using a variety of common isolation media to produce the yeast inocula, the germ tube methods tested ranked in the following order of decreasing sensitivity: SOC (97% +/- 1), serum (92% +/- 5), rabbit coagulase plasma with EDTA in combination with tryptic soy broth (89% +/- 5), TOC (89% +/- 6), and rabbit coagulase plasma with EDTA (83% +/- 4). In chlamydospore production, SOC also proved to be the most sensitive after 24 h incubation: SOC (96% +/- 2), TOC (80% +/- 2), and cornmeal-Tween 80 agar (14% +/- 3). Other medically important yeasts showed normal patterns of growth within 24 h on SOC, thus assisting in their identification. Eighty strains of Cryptococcus neoformans showed characteristic brown pigmentation on SOC and TOC within 18 h, while all other species of the genus Cryptococcus and 229 Candida isolates did not show a change in pigmentation.

Isolation of Cryptococcus species including C. neoformans from cloaca of pigeons

“…Then they were inoculated on four different laboratory media: Sabouraud dextrose agar (SDA), malt agar (MA), Staib Guizotia abyssinica agar 21 and Tween Oxgall Caffeic (TOC) medium, 22 all of them added with chloramphenicol (50 mg l −1 ) to avoid bacterial contamination. The plates were incubated at 30 °C and inspected daily until yeast‐like and/or brown pigmented colonies were observed.…”

Prevalence of Chlamydia trachomatis in human immunodeficiency virus-infected women in Cuba

“…For human papillomavirus (HPV) detection and mycoplasma (Ureaplasma urealiticum) PCR was employed (Manos et al 1989, Teng et al 1994, while for Neisseria gonorrhoeae, Trichomonas vaginalis, and Candida albicans, culture of the microorganisms was the technique assayed (Thayer & Martin 1966, Fleming et al 1977, Fouts & Kraus 1980. For Treponema pallidum VDRL was the technique employed.…”

Evolution of Cryptococcal Antigen Testing: What Is New?

“…In a study comparing conventional media and birdseed agar by culture of 35 clinical samples from AIDS patients, the results showed 100% sensitivity and specificity with plates incubated at 30°C [4, 29] • . TOC (tween 80-oxgall-caffeic acid) agar has been used for identification of C. neoformans within 24 hours from previously isolated colonies [30]. However, it requires extended incubation of 3–5 days if used as the primary isolation medium.…”