Characterization of Cryptococcus neoformans by random DNA amplification

Ruma, Patricia; Chen, S.C.A.; Sorrel, T.C.; Brownlee, A.

doi:10.1111/j.1472-765x.1996.tb00197.x

Cited by 39 publications

(32 citation statements)

References 28 publications

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“…Advantages included high discriminatory power, simplicity, and speed (61). This method separated C. gattii into three major molecular types, designated VGI, VGII, and VGIII (60). Use of the primers ERIC1 and ERIC2 revealed variation in the geographic distribution of these molecular types (59).…”

Section: Standardization Of Molecular Typing Systemsmentioning

confidence: 99%

“…In Asia and Australasia, the leading major molecular type is VGI, followed by VGII; VGIII has been isolated rarely (29,60,88) (Fig. 3, bottom, and 4).…”

Section: Global Distribution and Movement Of C Gattii Genotypesmentioning

confidence: 99%

“…RAPD analysis, based on the random amplification of DNA fragments using short arbitrary primers, was used initially for cryptococcal strain typing (59,60). Advantages included high discriminatory power, simplicity, and speed (61).…”

Section: Standardization Of Molecular Typing Systemsmentioning

confidence: 99%

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Cryptococcus gattii Infections

2014

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SUMMARY Understanding of the taxonomy and phylogeny of Cryptococcus gattii has been advanced by modern molecular techniques. C. gattii probably diverged from Cryptococcus neoformans between 16 million and 160 million years ago, depending on the dating methods applied, and maintains diversity by recombining in nature. South America is the likely source of the virulent C. gattii VGII molecular types that have emerged in North America. C. gattii shares major virulence determinants with C. neoformans , although genomic and transcriptomic studies revealed that despite similar genomes, the VGIIa and VGIIb subtypes employ very different transcriptional circuits and manifest differences in virulence phenotypes. Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis. Overall, currently available data indicate that the C. gattii VGI, VGII, and VGIII molecular types more commonly affect nonimmunocompromised hosts, in contrast to VGIV. New, rapid, cheap diagnostic tests and imaging modalities are assisting early diagnosis and enabling better outcomes of cerebral cryptococcosis. Complications of CNS infection include increased intracranial pressure, severe neurological sequelae, and development of immune reconstitution syndrome, although the mortality rate is low. C. gattii VGII isolates may exhibit higher fluconazole MICs than other genotypes. Optimal therapeutic regimens are yet to be determined; in most cases, initial therapy with amphotericin B and 5-flucytosine is recommended.

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Section: Standardization Of Molecular Typing Systemsmentioning

confidence: 99%

“…In Asia and Australasia, the leading major molecular type is VGI, followed by VGII; VGIII has been isolated rarely (29,60,88) (Fig. 3, bottom, and 4).…”

Section: Global Distribution and Movement Of C Gattii Genotypesmentioning

confidence: 99%

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Cryptococcus gattii Infections

2014

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“…In relation to other molecular techniques, RAPD analysis offers the advantage of requiring small amounts of DNA, simpler procedures, and the use of arbitrary primers (26). Due to these characteristics, RAPD has been widely used for human diseases to detect genomic variations among isolates of fungi such as Histoplasma capsulatum (27), Cryptococcus neoformans (19), Aspergillus fumigatus (1), and P. brasiliensis (3,9,12,13,23). Several authors have used the RAPD technique to investigate possible associations between P. brasiliensis fungus banding patterns and geographical distribution (3), clinical or animal origin (21), virulence and pathology (12,13), and atypical isolates not presenting with in vitro dimorphism (9) but, until now, little if any correlation was observed.…”

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Randomly Amplified Polymorphic DNA as a Valuable Tool for Epidemiological Studies of Paracoccidioides brasiliensis

et al. 2003

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Randomly amplified polymorphic DNA (RAPD) has been successfully used to detect genetic variations among isolates of Paracoccidioides brasiliensis. However, the usefulness of this technique for assessing important parasitic properties is still unconfirmed. In the present work we further investigated the applicability of RAPD in revealing important intrinsic and extrinsic features of this fungus associated with geographical origin, time of isolation, source of clinical specimen, clinical forms of human disease and also in vitro and in vivo susceptibility to antimicrobial and antifungal drugs. The RAPD patterns allowed us to distinguish all of the analyzed strains, which included 26 clinical isolates, 2 animal isolates, and 1 environmental isolate of P. brasiliensis obtained from different geographic regions, confirming the strong discriminating power of this technique. A phenetic tree, build from the RAPD data, showed that although the two nonclinical Brazilian strains were set together the majority of the clinical Brazilian strains were randomly distributed through different sub-branches of a major cluster without any correlation to any of the parameters analyzed. A second major cluster, however, has grouped isolates from Mato Grosso and Roraima (Brazil) that not only were susceptible in vitro to trimethoprim-sulfamethoxazole but also produced a good in vivo response. These results open new vistas for epidemiological and clinical studies of P. brasiliensis.Paracoccidioides brasiliensis is a dimorphic fungus alternating between the mycelial form observed in room temperatures and the yeast form found in infected tissues or in culture at 35 to 37°C. The human paracoccidioidomycosis caused by this fungus is characterized by a range of clinical manifestations from benign or asymptomatic forms to severe and disseminated disease that is often fatal. The exact causes of the clinical pleomorphism are not understood, but it is reasonable to presume that factors associated with both the fungus and the patient are involved. In relation to the fungus, although wide biological and biochemical diversity has been observed, no clear correlation with pathogenesis has been demonstrated (3,9,12,13,17,20,23). Until now very little has been known about the genome sequences of P. brasiliensis; hence, the use of molecular approaches for isolate typing has been difficult.The development of the randomly amplified polymorphic DNA (RAPD) technique represented a landmark in the molecular characterization of diverse organisms, especially for microbial strain identifications when very few genomic sequences are available. In relation to other molecular techniques, RAPD analysis offers the advantage of requiring small amounts of DNA, simpler procedures, and the use of arbitrary primers (26). Due to these characteristics, RAPD has been widely used for human diseases to detect genomic variations among isolates of fungi such as Histoplasma capsulatum (27), Cryptococcus neoformans (19), Aspergillus fumigatus (1), and P. brasiliensis (3,9,12,13,23). ...

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“…In recent years, epidemiologists have used a number of molecular tools to characterize isolates of medically important species (2,7,10,12,13) and to find relationships between molecular markers and different clinical features. The latter field of study consists of examining several genotypical features, normally DNA banding patterns, on the assumption that organisms similar for many parameters are very likely to be similar also in infective ability.…”

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confidence: 99%

Multicenter Comparison of Three Different Analytical Systems for Evaluation of DNA Banding Patterns from Cryptococcus neoformans

Cardinali¹,

Martini²,

Preziosi

et al. 2002

J Clin Microbiol

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The enormous improvement of molecular typing techniques for epidemiological and clinical studies has not always been matched by an equivalent effort in applying optimal criteria for the analysis of both phenotypic and molecular data. In spite of the availability of a large collection of statistical and phylogenetic methods, the vast majority of commercial packages are limited by using only the unweighted pair group method with arithmetic mean algorithm to construct trees and by considering electrophoretic pattern only as migration distances. The latter method has serious drawbacks when different runs (separate gels) of the same molecular analysis are to be compared. This work presents a multicenter comparison of three different systems of banding pattern analysis on random amplified polymorphic DNA, (GACA) 4 , and contour-clamped homogeneous electric field patterns from strains of Cryptococcus neoformans var. neoformans isolated in different clinical and geographical situations and a standard Saccharomyces cerevisiae strain employed as an outgroup. The systems considered were evaluated for their actual ability to(i) recognize identities, (ii) define complete differences (i.e., the ability to place S. cerevisiae out of the C. neoformans cluster), and (iii) estimate the extent of similarity among different strains. The ability to cluster strains according to the patient from which they were isolated was also evaluated. The results indicate that different algorithms do indeed produce divergent trees, both in overall topology and in clustering of individual strains, thus suggesting that care must be taken by individual investigators to use the most appropriate procedure and by the scientific community in defining a consensus system.

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Characterization of Cryptococcus neoformans by random DNA amplification

Cited by 39 publications

References 28 publications

Cryptococcus gattii Infections

Cryptococcus gattii Infections

Randomly Amplified Polymorphic DNA as a Valuable Tool for Epidemiological Studies of Paracoccidioides brasiliensis

Multicenter Comparison of Three Different Analytical Systems for Evaluation of DNA Banding Patterns from Cryptococcus neoformans

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