Microbiological characteristics of clinical isolates of Cryptococcus neoformans in Taiwan: serotypes, mating types, molecular types, virulence factors, and antifungal susceptibility

• Published in: Clinical microbiology and infection Vol. 16; no. 6; pp. 696 - 703
• Main Authors: Liaw, S-J., Wu, H-C., Hsueh, P-R.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01-06-2010; Blackwell Publishing Ltd; Wiley-Blackwell; Elsevier Limited
• Subjects: Amphotericin B; Amphotericin B - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antifungal agents; Antifungal Agents - pharmacology; Antifungal susceptibility; Azoles - pharmacology; Biological and medical sciences; Clinical isolates; Cryptococcosis - microbiology; Cryptococcus neoformans; Cryptococcus neoformans - classification; Cryptococcus neoformans - genetics; Cryptococcus neoformans - isolation & purification; Cryptococcus neoformans - pathogenicity; DNA Fingerprinting; DNA, Fungal - genetics; Epithelial cells; Female; fluconazole; Genes, Mating Type, Fungal; Genotype; Hospitals; Human mycoses; Humans; Infectious diseases; Itraconazole; L-Lactate dehydrogenase; Lung; Male; Mating types; Medical sciences; Melanin; Microbial Sensitivity Tests; Miscellaneous mycoses; molecular types; Mycological Typing Techniques; Mycoses; Pharmacology. Drug treatments; phospholipase; Phospholipase C; Polymerase chain reaction; Primers; Random Amplified Polymorphic DNA Technique - methods; Restriction fragment length polymorphism; Serotypes; Serotyping; Taiwan; Urease; virulence; Virulence Factors; Voriconazole; Asia; Taiwan; Antifungal susceptibility; molecular types; serotypes; Cryptococcus neoformans; virulence; mating types; Typing; Mycosis; Virulence; Cryptococcosis; Fungi; Infection; Antifungal agent; Microbiological investigation; Characteristics; Fungi Imperfecti; Serotype; Clinical isolate
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1111/j.1469-0691.2009.02930.x

This study investigated the microbiological characteristics of 100 clinical isolates of Cryptococcus neoformans species complex, including serotypes, mating types, molecular types, antifungal susceptibility and virulence. The isolates were collected at National Taiwan University Hospital from 1999 to 2004. Eight isolates of C. neoformans from pigeon droppings were also evaluated. Among these isolates, 99 were C. neoformans var. grubii serotype A and one was C. neoformans var. gattii serotype B. All of these isolates were α mating types. PCR fingerprinting, generated by primers M13 and (GACA)4, and URA5 gene restriction fragment length polymorphism analysis revealed that C. neoformans var. grubii isolates belonged to the VNI (98 isolates) and the VNII (one isolate) types, and the single C. neoformans var. gattii was VGI type. The similar profiles of clinical and environmental isolates suggest that patients might acquire these yeasts from the environment. The MIC90 for fluconazole, itraconazole, 5-flucytosine, voriconazole and amphotericin B against all C. neoformans isolates were 8, 0.5, 4, 0.125 and 0.5 mg/L, respectively. All clinical isolates produced urease, phospholipase, capsule and melanin, but these activities varied with individual isolates. Analysis of six clinical and two environmental isolates with various levels of phospholipase activity indicated a correlation between phospholipase activity and the ability to adhere to the lung epithelial cell line, A549. The extent of cell damage, as indicated by lactate dehydrogenase release, also paralleled the phospholipase activity of these isolates. In addition, production of melanin contributed significant protection against amphotericin B killing of the isolates tested.