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Biomedical subjects

R C Summerbell

Publications and source records attributed to R C Summerbell.

At least 73 records · Page 4Linked to original sources
PubMed1992

Graft-related endocarditis caused by Neosartorya fischeri var. spinosa.

The first case of endocarditis caused by Neosartorya fischeri var. spinosa is reported. The patient was a child who received a calf pericardium graft after removal of a previously inserted Dacron graft associated with deterioration of adjacent tissue. Copious vegetations removed from the heart were found to be composed of septate hyaline fungal filaments. The fungus was recognized in culture by its bivalved, winged, spiny ascospores, its Aspergillus fischerianus anamorph, and its thermotolerance.

Animals↗
PubMed1991

Normally saprobic cryptococci isolated from Cryptococcus neoformans infections.

We report two cases in which Cryptococcus laurentii was isolated from surgically resected pulmonary lesions but the cryptococcal cells is tissue reacted positively with a specific fluorescent antibody (FA) conjugate for Cryptococcus neoformans. Both patients had no apparent host defense defects. In both cases, multiple cryptococcal isolates were obtained from tissue, and yeastlike cells consistent with C. neoformans were seen in direct histology. The isolates were identified by assimilation patterns and standard procedures including phenoloxidase reactions. Since C. laurentii was consistently isolated by using stringent procedures, it was considered unlikely that the fungus represented surgical or laboratory contamination. Its presence may be the result of dual infection not detected by FA, but other possible explanations exist. The results show the value of the FA test in diagnostic mycology and call into question previous reports of cryptococci other than C. neoformans as agents of infection.

Adult↗
PubMed1990

Enzymatic activity profiling as a potential biotyping method for Ajellomyces dermatitidis.

Enzyme profiling was investigated as a means of recognizing biotypes and individual strains of Ajellomyces dermatitidis (anamorph, Blastomyces dermatitidis). Eighteen North American and 2 African representatives were tested with the Yeast-IDENT enzymatic activity profiling system (Analytab Products, Plainview, N.Y.). Significant variation was found between isolates, particularly in beta-galactosaminidase activity.

Aminopeptidases↗
PubMed1989

Potted plants in hospitals as reservoirs of pathogenic fungi.

The soils of five potted plants cultivated within a hospital were investigated for the presence of fungal opportunistic pathogens of humans. A total of 16 potentially pathogenic species were isolated, including Aspergillus fumigatus at up to 53.5 colony-forming units (CFU) per gram dry soil and Scedosporium apiospermum (Pseudallescheria boydii) at up to 97.0 CFU/g. Other common species included Phialophora verrucosa and Fusarium solani. Scedosporium inflatum, a recently described emerging pathogen, is reported for the first time from an environmental source. The results of this study, in combination with previous case reports linking mycoses to potted plants and available information on the establishment and dispersal of fungal opportunistic pathogens in indoor habitats, indicate that indoor plant soils constitute a serious mycotic hazard to the immunosuppressed patient.

Aspergillus↗
PubMed1989

Inheritance of restriction fragment length polymorphisms in Agaricus brunnescens.

The cultivated mushroom, Agaricus brunnescens, is secondarily homothallic; most basidia produce only two basidiospores, each of which receives two of the four post meiotic nuclei. The segregation of restriction fragment length polymorphisms (RFLPs) detected by four plasmid probes carrying single-copy nuclear DNA of Agaricus was followed in seven parental strains including commercial, wild-collected, and artificially synthesized heterokaryons. Of a total of 367 single-spore progeny examined, 351 (95.6%) were heteroallelic at all RFLP loci heteroallelic in the respective parents. Of the 16 segregant isolates, ten (2.7% of the total) were homoallelic at all segregating loci assayed, suggesting that these isolates were most probably derived from rare spores that had received only a single postmeiotic nucleus. Some of these ten isolates had recombinant genotypes. Only five isolates (1.4% of the total) showed homoallelism at one of the loci heteroallelic in the parent, while remaining heteroallelic at other loci. These five genotypes suggest that a crossover had occurred between a marker locus and its respective centromere. Taken together, the results suggest that meiosis in A. brunnescens is accompanied by low levels of recombination and that nonsister nuclei are preferentially incorporated into basidiospores after meiosis II.

Agaricales↗
PubMed1989

Onychomycosis, tinea pedis and tinea manuum caused by non-dermatophytic filamentous fungi.

Over 4000 cases of fungal nail, sole and palm infection recorded during a three-year study period were investigated to determine the prevalence and significance of etiologic agents other than dermatophytes and yeasts. Littman's oxgall agar, which permitted isolation of cycloheximide-sensitive species but restricted overgrowth by fast growing contaminants, was used to promote isolation of these disease agents. Non-dermatophytic filamentous fungi made up 2.3% of the confirmed etiologic agents obtained overall, and constituted 3.3% of the agents obtained from nail infections. The most common species were Scopulariopsis brevicaulis, Hendersonula toruloidea, and Aspergillus sydowii. Scytalidium hyalinum was recorded for the first time from Canada, and an instance of nail infection by Gymnascella dankaliensis was recorded. Only H. toruloidea and Sc. hyalinum caused palm and sole infections.

Foot Dermatoses↗
PubMed1988

An outbreak of Trichophyton tonsurans dermatophytosis in a chronic care institution for the elderly.

A nosocomial outbreak of dermatophytosis caused by Trichophyton tonsurans var. sulfureum subvar. perforans is reported in a nursing home for the elderly. The outbreak affected six residents and persisted for nine months despite remedial medical and sanitary measures. In a survey designed to determine the potential role of fomites in disease transmission, 129 environmental sites were sampled. A high proportion (22.3%) of the samples yielded T. tonsurans, including samples from beds, floors, and washroom facilities. Methods for the control of dermatophyte outbreaks in chronic care institutions are discussed.

Adult↗
PubMed1988

Tinea corporis caused by Microsporum canis: report of a nosocomial outbreak.

In an unusual nosocomial outbreak, 13 staff and 11 patients in an acute and chronic health care facility were infected with the zoophilic dermatophyte, Microsporum canis. The dermatophyte was apparently introduced into the facility by a single infected patient. Likely modes of subsequent disease transmission include person-to-person contact, handling of contaminated laundry, and use of a shared razor. Infection control measures for managing such outbreaks are discussed.

Adult↗
PubMed1988

Fusarium proliferatum as an agent of disseminated infection in an immunosuppressed patient.

Fusarium proliferatum was reported as the agent of a fatal disseminated infection in a child with lymphoblastic leukemia. The fungus has not been reported previously to cause disease in humans, but it is closely related to the known opportunistic pathogen F. verticillioides. It was distinguished by the production of clavate microconidia in chains from proliferating phialides. Resistance to amphotericin B and flucytosine in vitro was shown.

Antifungal Agents↗
PubMed1988

Rapid method for differentiation of Trichophyton rubrum, Trichophyton mentagrophytes, and related dermatophyte species.

Bromocresol purple-milk solids-glucose medium, proposed by Fischer and Kane in 1971 (Mycopathol. Mycol. Appl. 43:169-180, 1971) as an aid in the rapid determination of Trichophyton rubrum and Trichophyton mentagrophytes, was evaluated across a wide range of isolates to determine its accuracy and efficacy in the clinical laboratory. Results showed that it facilitated accurate determination of typical and atypical isolates of both species and also permitted the rapid identification of other closely related and similar species. Identification of all dermatophyte species tested was possible within 7 to 10 days. Occult contamination of isolates by antibiotic-resistant bacteria did not hinder identification.

Arthrodermataceae↗
PubMed1987

Improved procedures for differentiating Microsporum persicolor from Trichophyton mentagrophytes.

Microsporum persicolor, a zoophilic dermatophyte species, is seldom recorded causing human infections in North America. Its identification has been enhanced as a direct result of the development of improved techniques for its characterization. Identifying characteristics include induction of rough-walled macroconidia on sodium chloride-amended medium, absence of good growth at 37 degrees C, and absence of a pH change during growth on casein glucose medium. In contrast, Trichophyton mentagrophytes, a species commonly confused with M. persicolor, has smooth-walled macroconidia, grows well at 37 degrees C, and produces an alkaline reaction on casein glucose medium.

Culture Media↗
PubMed1987

Sodium chloride as aid in identification of Phaeoannellomyces werneckii and other medically important dematiaceous fungi.

Seventeen taxa of dematiaceous fungi isolated from humans were tested to determine their responses to various concentrations of sodium chloride in vitro. Five groups of species were recognized on the basis of differing tolerances. Phaeoannellomyces werneckii was distinguished by its tolerance of greater than or equal to 15% NaCl; most dematiaceous pathogens were suppressed at less than or equal to 7% NaCl.

Mitosporic Fungi↗