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R C Summerbell

Publications and source records attributed to R C Summerbell.

At least 19 recordsLinked to original sources
PubMed2006

Phaeoacremonium krajdenii, a cause of white grain eumycetoma.

We describe the first case of white grain pedal eumycetoma caused by Phaeoacremonium krajdenii in a 41-year-old man from Goa, India. Based on histological examination of biopsy tissue showing serpentine granules, a culture of the granules yielding phaeoid fungal colonies, and morphological characteristics and sequence comparison of the partial beta-tubulin gene with the ex-type isolate of P. krajdenii, the causal agent was identified as P. krajdenii.

Adult↗
PubMed2006

Dermatophytes: recognizing species of clonal fungi.

Now that molecular data have forever changed our perspective on the anthropophilic and zoophilic dermatophyte species, the concepts of these species needs re-evaluation. In this paper, main concepts (morphological, biological (BSC), phylogenetic and genealogical concordance phylogenetic species recognition (GCPSR)) are compared. While in geophilic dermatophytes the application of the BSC works well for species distinction and is supported by molecular data, it is not applicable for the anthropophilic and zoophilic dermatophytes where the majority of species reproduce purely asexually. Also, the application of GCPSR (an operational method to define the limits of species using molecular, multi-locus data) is problematic. GCPSR can be applied in recombining fungi even when recombination is infrequent and fungi lack phenotypic sexuality. In truly clonal fungi, however, no incongruities in multi-locus data are found, and thus separation of species may be difficult. In fungi this problem is currently taken to be non-existent, since clonality is supposed to lead to extinction. In the medically relevant, host-associated dermatophytes, however, is reason to suggest that clonal dermatophyte lineages are able to maintain ongoing populations and to follow independent evolutionary trajectories. We distinguish seasonal, short-lived and long-lived clonal species. The final goal of a species concept, in the dermatophytes as well as in other fungi, is to provide a taxonomic system that reflects the evolution of the fungal species so that the underlying biological trends elucidated in this way may be brought forward to help to guide the clinician in applying optimal therapy and prophylaxis. The application of the different species concepts may have an enormous impact on the nomenclature of dermatophytes, directly affecting the quality of communications with care providers.

Arthrodermataceae↗
PubMed2006

Subcutaneous phaeohyphomycosis caused by Phaeoacremonium parasiticum in a renal transplant patient.

A 49-year-old renally transplanted man, under a five-year course of immunosuppressive therapy with prednisone and cyclosporine A, experienced a subcutaneous phaeohyphomycosis caused by Phaeoacremonium parasiticum. The clinical presentation consisted of impressive, large, inflammatory and draining cystic tumors on the left foot that had been present for one year. A significant improvement was obtained with itraconazole plus intralesional injection with amphotericin B. Drug interaction was observed between itraconazole and cyclosporine A causing a severe hypertensive crisis and requiring a temporary sharp reduction in cyclosporine administration. Subcutaneous phaeohyphomycosis caused by P. parasiticum is uncommon among major organ transplant patients but several cases have previously been published and some patterns are emerging, e.g., limbs are generally involved but no known traumatic event has preceded lesion development. The identification of the case isolate was confirmed using a recently published online system based in part on beta-tubulin sequence comparison.

Amphotericin B↗
PubMed2005

Microcoding: the second step in DNA barcoding.

After the process of DNA barcoding has become well advanced in a group of organisms, as it has in the economically important fungi, the question then arises as to whether shorter and literally more barcode-like DNA segments should be utilized to facilitate rapid identification and, where applicable, detection. Through appropriate software analysis of typical full-length barcodes (generally over 500 base pairs long), uniquely distinctive oligonucleotide 'microcodes' of less than 25 bp can be found that allow rapid identification of circa 100-200 species on various array-like platforms. Microarrays can in principle fulfill the function of microcode-based species identification but, because of their high cost and low level of reusability, they tend to be less cost-effective. Two alternative platforms in current use in fungal identification are reusable nylon-based macroarrays and the Luminex system of specific, colour-coded DNA detection beads analysed by means of a flow cytometer. When the most efficient means of rapid barcode-based species identification is sought, a choice can be made either for one of these methodologies or for basic high-throughput sequencing, depending on the strategic outlook of the investigator and on current costs. Arrays and functionally similar platforms may have a particular advantage when a biologically complex material such as soil or a human respiratory secretion sample is analysed to give a census of relevant species present.

Biodiversity↗
PubMed2005

Recurrent colonization of successively implanted tracheoesophageal vocal prostheses by a member of the Fusarium solani species complex.

Tracheoesophageal vocal prostheses (TVP) in laryngectomized patients commonly deteriorate due to overgrowth by yeasts, particularly Candida species. We describe the first case of colonization of such devices by a member of the Fusarium solani species complex in a patient with a history of glottal carcinoma. Three isolates, from three prostheses, were found morphologically consistent with the traditional picture of F. solani. Ribosomal sequence analysis showed that the isolates belonged to a distinct, as yet apparently unnamed phylogenetic species within the F. solani species complex. This species, one of two distinct genetic types (genotype 2) traditionally considered part of the plant-pathogenic subtaxon Fusarium solani f. sp. radicicola, has not previously been identified as an agent of human or animal disease, although it is closely related to a known etiologic agent of mycetoma, an Acremonium-like species recently renamed Fusarium falciforme. Sequence and multisatellite M13 polymorphism analysis revealed no distinctions among the case isolates. Production of cyclosporine was detected for all three case isolates.

Aged↗
PubMed2004

Isolation of Neosartorya pseudofischeri from blood: first hint of pulmonary Aspergillosis.

We report a case of invasive pulmonary aspergillosis caused by Neosartorya pseudofischeri S. W. Peterson [anamorph Aspergillus thermomutatus (Paden) S. W. Peterson]. The diagnosis was initially based on a positive blood culture for a strain isolated from a neutropenic patient by means of a BACTEC 9050 blood culture system. The final diagnosis was established based on X-ray and computer tomography scan results as well as the detection of Aspergillus antigen in the patient's serum.

Adolescent↗
PubMed2003

Arthroconidial formation in Trichophyton raubitschekii.

Arthroconidia produced by dermatophytic fungi are considered to be the primary cause of skin and nail infections in humans and animals. Trichophyton rubrum is currently the most common cause of tinea pedis all over the world. The common form of T. rubrum produces a cottony colony in cultures that is characteristically low in conidia formation. The attempts to produce arthroconidia in T. rubrum have shown little success so far. Recently, Trichophyton raubitschekii, an anthropophilic dermatophyte prevalent in Asia, Africa, and the Mediterranean, has been recognized as a variant of T. rubrum. In cultures, T. raubitschekii is characterized by a granular colony form, and an abundance of both micro- and macroconidia. The present study reveals a predominance of arthroconidia in two T. raubitschekii cultures isolated from clinical materials. These isolates were able to maintain arthroconidiation in bimonthly subcultures throughout the entire course of this study. The growth parameters for in vitro cultivation of arthroconidia are described here. Arthroconidia prepared from T. raubitschekii cultures showed greater than 95% germination within 21 h of suspension in phosphate-buffered saline. The availability of arthroconidia in T. raubitschekii cultures appears to offer a practical means of characterizing infective cells in T. rubrum.

Culture Media↗
PubMed2002

Fungicidal activities of commonly used disinfectants and antifungal pharmaceutical spray preparations against clinical strains of Aspergillus and Candida species.

The antifungal efficacy of commercial chemical disinfectants and pharmaceutical antifungal agents against medically important moulds and yeast species was investigated. Chlorine, phenol, sodium dodecyl sulfate and quaternary ammonium salts were the chemical disinfectants, and bifonazole and terbinafine were the antifungal pharmaceutical products tested against clinical isolates of Aspergillus and Candida species. Fungal inocula were obtained from conidial preparations of two A. ochraceus strains and yeast cells of C. albicans, C. krusei and C. parapsilosis. The antifungal activities were evaluated either by determining the kill rate in a cell suspension media at different contact periods, or by examining the viability and growth on plates sprayed with the active ingredient. Chlorine (1%) was the only disinfectant with the ability to cause a rapid inactivation of all five strains. Phenol (5%) was equally effective against Candida species; however, a number of A. ochraceus conidia were able to survive this treatment for up to 1 h. Benzalkonium chloride (0.5%) and cetrimide (0.5%) were also able to disinfect the three Candida species rapidly; however, these two quaternary ammonium compounds were relatively ineffective against A. ochraceus. In spray experiments, quaternary ammonium compounds had a fungicidal activity against Candida species and were fungistatic against A. ochraceus conidia. All five fungal strains were able to resist 0.5% sodium dodecyl sulfate, present either in the suspension solution or on the sprayed plate. Of the two pharmaceutical antifungal products tested, bifonazole (1%) were essentially ineffective against all five strains. Terbinafine (1%) had a fungicidal activity against A. ochraceus and C. parapsilosis. In suspension experiments, an exposure to 0.01% terbinafine required a contact period of 1 h for a complete inactivation of A. ochraceus conidia and an onset of fungicidal effect on C. parapsilosis yeast cells. Terbinafine was only moderately effective against C. albicans and was completely ineffective against C. krusei.

Antifungal Agents↗
PubMed2002

Arachnomyces kanei (anamorph Onychocola kanei) sp. nov., from human nails.

Five isolates of a slow-growing cycloheximide resistant hyphomycetous fungus were obtained from nail specimens and investigated for their relationship to Onychocola canadensis (teleomorph Arachnomyces nodosetosus), a known agent of onychomycosis. In one patient diagnosed with superficial white onychomycosis, etiology was confirmed by a nail sample showing atypical filaments in direct microscopy, and by a follow-up specimen yielding cultures of the same fungus. A case of mixed infection with Aspergillus sydowii was also confirmed after examination of cultures grown from three successive microscopic-positive hallux nail specimens. For other isolates, etiological significance could not be confirmed by repeat sampling or results of direct microscopy were negative or unknown. Mating experiments yielded setose ascomata containing smooth oblate ascospores typical of Arachnomyces species. Phylogenetic analysis of ITS 2 region sequences support the conspecificity of the isolates and their placement within the genus. A. kanei sp. nov. (anamorph O. kanei sp. nov.) is described.

Aged↗
PubMed2002

Analysis of phylogenetic relationship of Cylindrocarpon lichenicola and Acremonium falciforme to the Fusarium solani species complex and a review of similarities in the spectrum of opportunistic infections caused by these fungi.

An emerging pattern of similarity in medical case reports led to a project to compare the phylogenetic affinities of two well-known tropical fungal opportunistic pathogens, Cylindrocarpon lichenicola and Acremonium falciforme, to members of the Fusarium solani species complex. C. lichenicola and A. falciforme, despite their deviating conidial morphologies, were shown via sequencing of the ribosomal large subunit to be well instituted within a clade mainly consisting of typical F. solani strains and other species until recently considered variants of F. solani. The original name Fusarium lichenicola C. B. Massalongo is reestablished, and the new combination F. falciforme is made. Recognition of these species as fusaria is necessary for correct interpretation of current and future molecular diagnostic tests. Reevaluation of species morphology in light of the molecular findings showed that certain features, especially elongate filiform conidiophores with integrated terminal phialides, facilitate correct microscopic classification of these atypical Fusarium species. There is a strong and underrecognized overlap in the spectra of cases caused by members of the F. solani clade, particularly ocular infections, mycetomas, and, in the neutropenic host, disseminated and other serious systemic infections. A novel synthesis of case reports shows that patients from areas with warm climates may develop a distinctive fusarial intertrigo caused by F. solani, Fusarium lichenicola, or Fusarium oxysporum.

Acremonium↗
PubMed2001

Fusariosis associated with pathogenic fusarium species colonization of a hospital water system: a new paradigm for the epidemiology of opportunistic mold infections.

We sought the reservoir of Fusarium species in a hospital with cases of known fusarial infections. Cultures of samples from patients and the environment were performed and evaluated for relatedness by use of molecular methods. Fusarium species was recovered from 162 (57%) of 283 water system samples. Of 92 sink drains tested, 72 (88%) yielded Fusarium solani; 12 (16%) of 71 sink faucet aerators and 2 (8%) of 26 shower heads yielded Fusarium oxysporum. Fusarium solani was isolated from the hospital water tank. Aerosolization of Fusarium species was documented after running the showers. Molecular biotyping revealed multiple distinct genotypes among the isolates from the environment and patients. Eight of 20 patients with F. solani infections had isolates with a molecular match with either an environmental isolate (n=2) or another patient isolate (n=6). The time interval between the 2 matched patient-environment isolates pairs was 5 and 11 months, and 2, 4, and 5.5 years for the 3 patient-patient isolate pairs. The water distribution system of a hospital was identified as a reservoir of Fusarium species.

Air Microbiology↗
PubMed2001

Itraconazole and terbinafine treatment of some nondermatophyte molds causing onychomycosis of the toes and a review of the literature.

BACKGROUND: Onychomycosis may be caused by dermatophytes (which form the majority of organisms), Candida species, and nondermatophyte molds. OBJECTIVE: To evaluate the efficacy and safety of itraconazole and terbinafine in the treatment of some nondermatophyte molds that cause toe onychomycosis and to review the literature on the treatment of nondermatophyte mold toe onychomycosis using the oral antifungal agents. PATIENTS AND METHODS: Patients with nondermatophyte mold toe onychomycosis were treated in an open, prospective manner with either itraconazole (pulse) or terbinafine therapy. In each instance, light microscopic examination was consistent with the diagnosis of a nondermatophyte mold. For each patient, mycological evaluation of the target nail resulted in 3 or more successive cultures yielding growth of the mold alone. RESULTS: All 15 patients had onychomycosis of the toes which was of the distal and lateral type. The patients were treated with itraconazole given as the standard 3 pulses with additional pulses administered depending upon the response exhibited by the toe onychomycosis in the patient. Similarly, terbinafine was given for 12 weeks with additional therapy administered as dictated by the response. Efficacy parameters were mycological cure (MC) and clinical cure (CC). Mycological cure was negative light microscopic examination (KOH) and culture. Clinical cure was the appearance of a completely normal-looking nail. At month 12 from the start of treatment, the response was as follows: Scopulariopsis brevicaulis: itraconazole (MC 4/4, CC 2/4) and terbinafine (MC 0/1, CC 0/1), Fusarium species: itraconazole (MC 1/1, CC 1/1) and terbinafine (MC 0/1, CC 0/1), Aspergillus species: itraconazole (MC 5/6, CC 3/6), Alternaria alternata: itraconazole (MC 0/1,CC 0/1), and Onychocola canadensis: itraconazole (MC 1/1, CC 0/1). There were no significant clinical or laboratory adverse effects. CONCLUSIONS: In the present series itraconazole demonstrated efficacy against onychomycosis of the toenails caused by S. brevicaulis and Aspergillus species. A review of the literature confirms our experience with itraconazole and further suggests that terbinafine may also demonstrate efficacy against cases of S. brevicaulis and Aspergillus toe onychomycosis. Additionally, reports in the literature suggest that pedal onychomycosis caused by Fusarium species may also show response to itraconazole and terbinafine. For the other species, there are fewer data, making it difficult to draw conclusions.

Adult↗
PubMed2001

Epidemiology of Malassezia yeasts associated with pityriasis versicolor in Ontario, Canada.

The genus Malassezia was recently revised to include seven species, but the clinical significance of each of these species is not clearly understood. To obtain a better understanding of the contribution of individual Malassezia species to the epidemiology of pityriasis (tinea) versicolor, we used Leeming-Notman medium to culture patient skin specimens showing positive evidence of Malassezia infection in direct microscopy. Isolates were identified on the basis of recently published morphological and physiological tests for distinction of the new species. Identification using recently developed molecular criteria was also carried out for the ambiguous cases. Malassezia species were cultured from 111 cases of pityriasis versicolor in the Canadian province of Ontario. The most frequently isolated species were Malassezia sympodialis, M. globosa and M. furfur which respectively made up 59.4%, 25.2% and 10.8% of the isolated etiological agents. M. globosa was commonly isolated from a small number of pityriasis versicolor specimens obtained from investigators outside Canada. A large number of additional Ontario specimens with positive direct microscopy failed to yield a culture; however, it is suggested that this is consistent with the standard sampling practice of scraping the older portions of pityriasis lesions rather than the margins, where viable fungal cells are most likely to occur.

Canada↗
PubMed2001

Quantitative culture of Malassezia species from different body sites of individuals with or without dermatoses.

Quantitative cultures were obtained using contact plates to determine whether the quantity and composition of Malassezia species at a given anatomic site in normal individuals differs from that of patients with various cutaneous dermatoses. The sample included 20 clinically healthy individuals (without any dermatosis) and 110 patients with dermatoses (including 31 with atopic dermatitis [AD], 28 with psoriasis [PS], 28 with seborrheic dermatitis [SD] and 23 with pityriasis versicolor [PV]). Contact plates filled with special culture medium were used to obtain a quantitative culture from five body sites (scalp, forehead, arm, trunk and leg) of every individual. The number of cfu were recorded for every plate that grew Malassezia yeasts, and 3-5 colonies were isolated for identification to species level using microscopic, physiological and molecular characteristics. The mean cfu counts observed among patients with AD, PS and SD was significantly lower than normal control subjects (P < 0.05). The mean cfu counts from PV patients was not different from that of healthy control subjects. Overall, for all conditions considered together, the mean cfu counts in lesional sites were significantly lower than in non-lesional sites (P <0.05). Furthermore, the mean cfu counts from lesional sites in patients with AD and PS were significantly lower than the corresponding value in patients with PV (P <0.05). Six Malassezia species were recovered from the different dermatoses. Malassezia sympodialis was the most common species associated with AD and PV patients and healthy control subjects, while M. globosa was most frequently isolated from PS and SD patients. More than one Malassezia species was recovered at any given anatomic site from both controls as well as individuals with dermatoses. M. globosa was equally likely to be recovered from scalp, forehead and trunk, but less likely to derive from arms and legs. M. restricta and M. slooffiae were recovered more frequently from the upper body (scalp and forehead) than from the lower body. Among normal individuals and for patients with AD and PV, M. sympodialis was significantly more likely to affect the forehead than the legs.

Adult↗
PubMed2001

Comparative efficacies of commonly used disinfectants and antifungal pharmaceutical spray preparations against dermatophytic fungi.

Arthroconidia from five fungal strains belonging to three Trichophyton species, Trichophyton mentagrophytes, T. raubitschekii and T. tonsurans, were tested against commercial chemical disinfectants and pharmaceutical antifungal agents. The chemical disinfectants included chlorine, phenol, sodium dodecyl sulphate and several quaternary ammonium salts, while the two pharmaceutical preparations contained bifonazole and terbinafine as active agents. Arthroconidia were exposed to the antifungal agent either in a suspension solution for a given period of time and assayed for kill rate, or on a sprayed agar plate and monitored for surviving colonies over a period of 14 days. Chlorine (1%) and terbinafine (0.01%) were found to be high level disinfectants bringing about a rapid inactivation of conidia in all five strains. Phenol was equally effective against T. raubitschekii and T. tonsurans; however, T. mentagrophytes cells were able to survive for up to 1 h in 5% phenol. Quaternary ammonium compounds were less rapid in their action against dermatophytes and were needed at a level of about 0.5% to be completely fungicidal. Three commercial spray formulations with a range of 0.1 to 0.3% quaternary ammonium salts were fungistatic against T. mentagrophytes strains. Bifonazole (1%) was also fungistatic in its action against T. mentagrophytes. Sodium dodecyl sulphate (0.5%) was largely ineffective against Trichophyton arthroconidia.

Antifungal Agents↗
PubMed2001

Utility of inoculum counting (Walshe and English criteria) in clinical diagnosis of onychomycosis caused by nondermatophytic filamentous fungi.

Opportunistic onychomycosis caused by nondermatophytic molds may differ in treatment from tinea unguium. Confirmed diagnosis of opportunistic onychomycosis classically requires more than one laboratory analysis to show consistency of fungal outgrowth. Walshe and English in 1966 proposed to extract sufficient diagnostic information from a single patient consultation by counting the number of nail fragments positive for inoculum of the suspected fungus. Twenty fragments were plated per patient, and each case in which five or more fragments grew the same mold was considered an infection by that mold, provided that compatible filaments were also seen invading the nail tissue by direct microscopy. This widely used and often recommended method has never been validated. Therefore, the validity of substituting any technique based on inoculum counting for conventional follow-up study in the diagnosis of opportunistic onychomycosis was investigated. Sampling of 473 patients was performed repeatedly. Nail specimens were examined by direct microscopy, and 15 pieces were plated on standard growth media. After 3 weeks, outgrowing dermatophytes were recorded, and pieces growing any nondermatophyte mold were counted. Patients returned on two to eight additional occasions over a 1- to 3-year period for similar examinations. Onychomycosis was etiologically classified based on long-term study. Opportunistic onychomycosis was definitively established for 86 patients. Counts of nondermatophyte molds in initial examinations were analyzed to determine if they successfully predicted both true cases of opportunistic onychomycosis and cases of insignificant mold contamination. There was a strong positive statistical association between mold colony counts and true opportunistic onychomycosis. Logistic regression analysis, however, determined that even the highest counts predicted true cases of opportunistic onychomycosis only 89.7% of the time. The counting criterion suggested by Walshe and English was correct only 23.2% of the time. Acremonium infections were especially likely to be correctly predicted by inoculum counting. Inoculum counting could be used to indicate a need for repeat studies in cases of false-negative results from laboratory direct microscopy. Inoculum counting cannot serve as a valid substitute for follow-up study in the diagnosis of opportunistic onychomycosis. It may, nonetheless, provide useful information both to the physician and to the laboratory, and it may be especially valuable when the patient does not present for follow-up sampling.

Aged↗
PubMed2001

Variation in restriction fragment length polymorphisms among serial isolates from patients with Trichophyton rubrum infection.

Molecular genotyping of strains of Trichophyton rubrum and T. mentagrophytes from patients with onychomycosis of the toes was performed to ascertain whether the fungal genotype changes over the course of time as sequential samples were obtained from patients receiving antifungal therapy and during follow-up. Sixty-six serial strains of T. rubrum and 11 strains of T. mentagrophytes were obtained from 20 patients (16 patients with T. rubrum, 4 with T. mentagrophytes) who were treated with oral antifungal therapy and observed over periods of up to 36 months. These strains were screened for genetic variation by hybridization of EcoRI-digested genomic DNAs with a probe amplified from the small-subunit (18S) ribosomal DNA and adjacent internal transcribed spacer regions. A total of five restriction fragment length polymorphism (RFLP) types were observed among 66 strains of T. rubrum. Two major RFLP types, differentiated by one band shift, represented 68% of the samples. None of the patients had a unique genotype. More than one RFLP type was often observed from a single patient (same nail) over a period of 1, 2, or 3 years, even in cases that did not appear cured at any time. Samples taken from different nails of the same patient had either the same or a different genotype. The genotypic variation did not correspond to any detectable phenotypic variation. Furthermore, no correlation was observed between the efficacy of the treatment administered and the genotype observed. While the DNA region studied distinguished among T. rubrum, T. mentagrophytes, and T. tonsurans, intraspecific RFLP variation was observed for T. rubrum and T. mentagrophytes strains. While independent multiple infection and coinhabitation of multiple strains may explain the presence of different genotypes in a nail, microevolutionary events such as rapid substrain shuffling, as seen in studies of repetitive regions in Candida species, may also produce the same result. The recovery of multiple strains during the course of sequential sampling of uncured patients further suggests that the typing system is not able to distinguish between relapse or reinfection, ongoing infection, and de novo infection.

DNA, Fungal↗