agar and AIDS-Related-Opportunistic-Infections

In the present report, we describe an unusual case of mixed infection of Candida albicans and Talaromyces marneffei in the oral cavity and oropharynx with cutaneous involvement. On the CHROMagar Candida plate, green colonies (identified as C. albicans) and tiny violet colonies (identified as T. marneffei) grew from the throat swab after incubation for 96 hours. 10 clinical isolates of T. marneffei were used to verify their color production on CHROMagar Candida. All colonies were violet on the fourth, seventh and ninth day incubated at 37 °C. T. marneffei appears violet on the CHROMagar Candida plate, but it may be easily ignored because of its slow growth and small colony size, especially after incubation for 48 hours. Therefore, when using CHROMagar Candida plate to detect specimens in AIDS patients, special attention must be paid to detect non-yeasts such as T. marneffei for up to 96 hours.

Topics: Agar; AIDS-Related Opportunistic Infections; Candida albicans; Coinfection; Culture Media; Humans; Male; Middle Aged; Mouth; Mycological Typing Techniques; Mycoses; Oropharynx; Talaromyces; Time Factors

Candida dubliniensis is an emerging yeast pathogen isolated mainly from immunocompromised patients. As molecular tests are currently unsuitable for use in routine diagnostic laboratories, we compared a variety of phenotypic techniques for differentiating C. albicans and C. dubliniensis. The tests included: colony colour on CHROMagar Candida medium; growth at 37 degrees C and 45 degrees C; ability to produce germ tubes and chlamydospores; and the Auxacolor system. The organisms included 105 isolates previously identified as C. albicans, 10 reference strains of C. albicans, 2 reference strains of C. dubliniensis and 102 fresh clinical isolates identified as C. albicans. None of the tests alone was satisfactory but a combination of 3 tests may be suitable for presumptive identification of C. dubliniensis.

Topics: Agar; AIDS-Related Opportunistic Infections; Candida; Candida albicans; Candidiasis; Chromogenic Compounds; Color; Communicable Diseases, Emerging; Culture Media; Culture Techniques; Diagnosis, Differential; DNA, Fungal; Drug Resistance, Fungal; Humans; Immunocompromised Host; Mycological Typing Techniques; Phenotype; Sensitivity and Specificity; Temperature; Time Factors

Ten different agar media were tested for the in vitro growth of Mycobacterium genavense in primary cultures and in subcultures from BACTEC vials. These agar media were based on Middlebrook 7H9, 7H10 and 7H11, and supplemented with additives: mycobactin J, yeast extract, charcoal, or defibrinated sheep blood. Some media were acidified with phosphoric acid to a final pH of 6.2 +/- 0.2. Fourteen M. genavense strains from nude mouse organs as well as one decontaminated clinical specimen (from a bird) were tested. The optimal medium for primary cultures of M. genavense was Middlebrook 7H11 acidified to pH 6.2 +/- 0.2 and supplemented with charcoal and sheep blood: on this medium, all strains produced colonies within 6-12 weeks of incubation in numbers approaching the number of bacilli inoculated. It was also the only medium to support the growth of the decontaminated clinical specimen. Added blood and charcoal appeared not as essential for subcultures as for primary cultures. Three media supported the growth of all strains within 1 month incubation: they were acidified, and were supplemented with yeast extract or pancreatic digest of casein, and with either blood or charcoal.

Topics: Agar; AIDS-Related Opportunistic Infections; Animals; Bird Diseases; Birds; Blood; Charcoal; Culture Media; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Mycobacterium; Mycobacterium Infections