Dormant infections can become reactivated years after having been acquired on another continent.

The in vitro susceptibilities of a worldwide collection of 350 Cryptococcus gattii isolates to seven antifungal drugs, including the new triazole isavuconazole, were tested. With amplified fragment length polymorphism (AFLP) fingerprinting, human, veterinary, and environmental C. gattii isolates were subdivided into seven AFLP genotypes, including the interspecies hybrids AFLP8 and AFLP9. The majority of clinical isolates (n ‫؍‬ 215) comprised genotypes AFLP4 (n ‫؍‬ 76) and AFLP6 (n ‫؍‬ 103). The clinical AFLP6 isolates had significantly higher geometric mean MICs for flucytosine and fluconazole than the clinical AFLP4 isolates. Of the seven antifungal compounds examined in this study, isavuconazole had the lowest MIC 90 (0.125 g/ml) for all C. gattii isolates, followed by a 1 log 2 dilution step increase (MIC 90 , 0.25 g/ml) for itraconazole, voriconazole, and posaconazole. Amphotericin B had an acceptable MIC 90 of 0.5 g/ml, but fluconazole and flucytosine had relatively high MIC 90 s of 8 g/ml.

During a European Confederation of Medical Mycology (ECMM) prospective survey of cryptococcosis in Europe (from July 1997 to December 1999) 655 cases were reported from 17 countries; 565 of the completed questionnaires were evaluable. Cryptococcosis was associated with HIV infection in 77% of cases (range 57.5-94%). Assessment of the laboratory data highlighted the lack of defined standard procedures for the diagnosis of cryptococcosis: the antigen test was not usually used for screening, the disease was mainly recognised when meningitis occurred (65% of patients) and, with the exception of a few cases, the extent of the infection was not investigated. Cryptococcus neoformans was the etiological agent in all of the cases except for six caused by C. gattii and four by other Cryptococcus species. A total of 311 C. neoformans strains were serotyped by Crypto Check latex agglutination, genotyped by PCR-fingerprinting using the (GACA)4 oligonucleotide as a single primer, and their mating type was determined by PCR of the STE20 alleles. Serotype A was the most represented (51% of the isolates), followed by serotype D (30%) and serotype AD (19%). PCR-fingerprinting analysis significantly increased the percentage of hybrid strains to 30%, as 6% of the serotype A and 28% of the serotype D isolates were of the VN3 or VN4 hybrid genotype. In addition, the mating type determinations revealed the MATa serotype A allele in one haploid strain and 28 hybrids, and hybrid isolates with a single mating type (four Aalpha and two Dalpha) were also identified. This is the first prospective survey to be carried out in Europe which has attempted to investigate the epidemiology of cryptococcosis and the population structure of C. neoformans, and the results obtained thus far show the widespread involvement of AD hybrid strains in C. neoformans infections.

Pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) analysis, serotype, and killer toxin sensitivity patterns of a wide range of saprobic, clinical, and veterinary isolates of both varieties of Cryptococcus neoformans were examined. C. neoformans var. neoformans and C. neoformans var. gattii differed in chromosomal makeup, W D patterns, and killer sensitivity patterns. These results suggest that there are two separate species rather than two varieties. No clear genetic or phenotypic differences were observed among the clinical, saprobic, and veterinary isolates within each taxon. The serotypes differed substantially in their RAPD characteristics. Geographical clustering was observed among the isolates of C. neoformans var. gattii, but not among the isolates of C. neoformans var. neoformans. The isolates of each taxon that originated from restricted geographical areas often had identical or similar karyotypes and RAPD patterns, suggesting that clonal reproduction had occurred. The combination of PFGE and RAPD analysis allowed us to distinguish almost all isolates. This combination of techniques is recommended for further research on epidemiological, ecological, and population issues.Cryptococcus neoformans (Sanfelice) Vuillemin is a zoopathogenic basidiomycetous yeast (teleomorph, Filobasidiella neoformans Kwon-Chung) which is usually encountered in the imperfect state. This fungus can cause serious infections, especially in immunocompromised patients. Estimates of the incidence rate in AIDS patients range from 5 to 30%, with the highest numbers occurring in sub-Saharan Africa (21, 30). In human immunodeficiency virus-seropositive individuals, an infection with C. neoformans indicates progression to AIDS (40). The problem is aggravated by the emergence of cryptococcal strains that have become resistant to some of the most widely used antifungal agents (11, 19, 33, 34).According to the current classification, C. neoformans consists of the following two varieties: C. neoformans var. neoformans, with serotypes A, D, and AD (teleomorph, F. neoformans var. neoformans), and C. neoformans var. gattii Vanbreuseghem et Takashio, with serotypes B and C (teleomorph, F. neoformans var. bacillispora Kwon-Chung) (15, 18, 22, 23,37). The occurrence of recombinants between strains of C. neoformans var. neoformans and C. neoformans var. gattii and the demonstration of genetic recombination in the F1 generation have suggested that these taxa are varieties (25,41), but no genetic analysis of the F2 generation has been performed. In contrast, rather low DNA-DNA reassociation values (range, 55 to 63%) (1) have been observed between isolates of the two varieties, which may reflect genetic divergence between the two taxa. The two varieties differ in karyotype (54), in a number of physiological characteristics (e.g., assimilation of D-proline, Dtryptophan, and L-malic acid), in regulation of creatinine deaminase by ammonia production (2,13, 31,38), and in sensitivity to killer toxins of Cryptococcus lauren...

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