Biomedical subjects

R B Caligiorne

Publications and source records attributed to R B Caligiorne.

6 recordsLinked to original sources

PubMed2005

Internal transcribed spacer rRNA gene-based phylogenetic reconstruction using algorithms with local and global sequence alignment for black yeasts and their relatives.

Sequences of rRNA gene internal transcribed spacer (ITS) of a standard set of black yeast-like fungal pathogens were compared using two methods: local and global alignments. The latter is based on DNA-walk divergence analysis. This method has become recently available as an algorithm (DNAWD program) which converts sequences into three-dimensional walks. The walks are compared with, or fit to, each other generating global alignments. The DNA-walk geometry defines a proper metric used to create a distance matrix appropriated for phylogenetic reconstruction. In this work, the analyses were carried out for species currently classified in Capronia, Cladophialophora, Exophiala, Fonsecaea, Phialophora, and Ramichloridium. Main groups were verified by small-subunit rRNA gene data. DNAWD applied to ITS2 alone enabled species recognition as well as phylogenetic reconstruction reflecting clades discriminated in small-subunit rRNA gene phylogeny, which was not possible with any other algorithm using local alignment for the same data set. It is concluded that DNAWD provides rapid insight into broader relationships between groups using genes that otherwise would be hardly usable for this purpose.

Algorithms↗

PubMed2003

Brain abscess caused by Cladophialophora (Xylohypha) bantiana in a renal transplant patient.

Infectious disease is the most significant cause of morbidity and mortality in allotransplantation because of heavy immunosuppression. Brain abscesses caused by melanized fungi have been found occasionally and are an example of this complication. In this paper, we describe a case in a 61-year-old black man, who received a cadaveric kidney transplantation in December 1993, followed by triple therapy with cyclosporine, azathioprine, and prednisone. The patient developed right hemiparesis at the beginning of April 1998. A computed tomography scan showed a mass in the left parieto-temporal region of the brain. The patient underwent surgery and a brown-colored encapsulated brain abscess was resected. Histology of the tissue revealed a large number of pigmented fungal hyphae. Culture in a Sabouraud dextrose medium with cyclohexamide and chloramphenicol at 25 degrees C resulted in the growth of dark-green colonies. The fungus identified was Cladophialophora bantiana, based on characteristic microscopic features and on growth at 40 degrees C. The abscess recurred in spite of treatment with fluconazole. The patient was submitted to a second brain surgical procedure and was treated with amphotericin B in addition to fluconazole. Ten days later the patient's blood cultures became positive for Escherichia coli. After 3 days the patient died due to septic shock.

Ascomycota↗

PubMed2003

Species diversity and polymorphism in the Exophiala spinifera clade containing opportunistic black yeast-like fungi.

A monophyletic group of black yeast-like fungi containing opportunistic pathogens around Exophiala spinifera is analyzed using sequences of the small-subunit (SSU) and internal transcribed spacer (ITS) domains of ribosomal DNA. The group contains yeast-like and annellidic species (anamorph genus Exophiala) in addition to sympodial taxa (anamorph genera Ramichloridium and Rhinocladiella). The new species Exophiala oligosperma, Ramichloridium basitonum, and Rhinocladiella similis are introduced and compared with their morphologically similar counterparts at larger phylogenetic distances outside the E. spinifera clade. Exophiala jeanselmei is redefined. New combinations are proposed in EXOPHIALA: Exophiala exophialae for Phaeococcomyces exophialae and Exophiala heteromorpha for E. jeanselmei var. heteromorpha.

Ascomycota↗

PubMed1999

In vitro susceptibility of chromoblastomycosis and phaeohyphomycosis agents to antifungal drugs.

The in vitro susceptibility of chromoblastomycosis and phaeohyphomycosis agents to antifungal drugs was appraised using the reference macrodilution method proposed by the National Committee for Clinical Laboratory Standards (NCCLS) for yeasts modified for filamentous fungi. The antifungal drugs amphotericin B, 5-fluorocytosine, itraconazole and fluconazole were tested against one environmental and 18 clinical isolates. This work amended the macrodilution methods proposed by NCCLS and suggests that a conidial suspension free of hyphae leads to a more reliable assay and provides for better reproducibility. The macrodilution method was performed with 10(4) conidia ml-1. The MIC values ranged from 1.0 to 16.0 micrograms ml-1 for amphotericin B and 3.12 to 25.0 micrograms ml-1 for 5-fluorocytosine. A MIC range of 0.06 to 1.95 micrograms ml-1 was determined for itraconazole while 2.0 to 64.0 micrograms ml-1 was detected for fluconazole.

Antifungal Agents↗

PubMed1999

Dematiaceous fungal pathogens: analysis of ribosomal DNA gene polymorphism by polymerase chain reaction-restriction fragment length polymorphism.

Restriction fragment length polymorphisms (RFLP) of ribosomal gene small subunit (SSU rDNA) and internal transcribed spacer (ITS) regions was examined in 12 isolates of dematiaceous agents of chromoblastomycosis and phaeohyphomycosis. The amplicon length of the fragment ITS1-ITS4, comprising the 5.8 rDNA and ITS1-ITS2 spacers, ranged in size from 620 to 690 bp. This result indicated a polymorphism of size in this region. Additionally the RFLP profiles showed a high degree of inter- and intra-specific variability. In contrast, the SSU rDNA amplification, using NS1-NS2 primers, originated a fragment of approximately 570 bp and its restriction profile proved to be well conserved among the species studied and was clustered into only two genetically heterogeneous groups, the first one formed by Fonsecaea pedrosoi and Fonsecaea compacta and the second one formed by Cladophialophora (Cladosporium) carrionii, Cladophialophora (Xylohypha) bantiana, Phialophora verrucosa and Rhinocladiella species.

Base Sequence↗

PubMed1999

Use of RAPD (random amplified polymorphic DNA) to analyse genetic diversity of dematiaceous fungal pathogens.

Thirteen strains of chromoblastomycosis and phaeohyphomycosis etiologic agent fungi were obtained from different geographical origins. These strains were genotypically compared by means of the RAPD (Random Amplified Polymorphic DNA) technique. The data generated showed a high degree of polymorphism between distinct species and a low polymorphism between strains of the same species. The results generated by these tests were subjected to a numerical taxonomy analysis, using the unweighted pair-group method. A phenogram was constructed for the set of strains studied. Based on its structure, we concluded that genotypical data provide enough information to us to use the unweighted pair-group method to cluster the strains in accordance to their respective species. The phenogram grouped in a single branch the strains of Fonsecaea pedrosoi and F. compacta species, indicating a great similarity between these fungi, and suggesting that the classification as distinct species may not be appropriate for these species of the genus Fonsecaea.

Chromoblastomycosis↗