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Biomedical subjects

A A Padhye

Publications and source records attributed to A A Padhye.

At least 37 records · Page 2Linked to original sources

Biosafety considerations in handling medically important fungi.

Over 500,000 workers in the USA alone are employed in laboratories that range from small physician offices to large clinical laboratories handling microbes for comprehensive research and/or diagnostic work. These workers are exposed to a variety of potential occupational health risks such as exposure to infectious clinical materials, environmental specimens, cultures, complex and inflammable chemicals, radiation, and electrical and mechanical hazards. As members of the International Society for Human and Animal Mycology, we have no policy statement on biosafety standards for handling medically important fungi. The intent of the symposium is to cover some of the important aspects of biosafety; (1) standards in handling dimorphic fungal pathogens; (2) the principles and criteria of biosafety levels and classification of known medically important fungi, aerobic actinomycetes, environmental fungi according to their biosafety levels; (3) medically important fungal waste and its safe disposal; and (4) biosafety and regulatory considerations in handling and mailing medically important fungi in a culture collection.

Animals↗

Antigenic relationships among pathogenic Beauveria bassiana with Engyodontium album (= B. alba) and non-pathogenic species of the genus Beauveria.

Exoantigenic extracts of 15 isolates belonging to hyalohyphomycosis-causing Beauveria bassiana (1), and Engyodontium album (1), as well as other species of the genus Beauveria (one isolate each of B. brogniartii, B. densa, B. stephanoderis, B. velata, B. vermiconia and six isolates of unknown Beauveria species) were studied. Aqueous-merthiolated extracts derived from 10-day-old Sabouraud's dextrose agar slant cultures (25 degrees C) were concentrated (25X), and reacted against rabbit anti-B. bassiana serum in the presence of partially purified homologous antigen (20X) prepared from 5-week-old shaken cultures (30 degrees C), using a microimmunodiffusion procedure. Beauveria bassiana reference antigen and antiserum reacted to produce four bands of identity. With the exception of E. album, which was negative, extracts of the isolates of B. brogniartii, B. densa, B. stephanoderis, B. velata, B. vermiconia and the unknown Beauveria species all produced 2-4 lines of identity against the homologous anti-B. bassiana serum. These results suggested that all the species of the genus Beauveria tested were antigenically related to B. bassiana. Engyodontium album demonstrated antigenic distinctness, however, from B. bassiana and thus supported the validity of this taxon.

Animals↗

Primary cutaneous zygomycosis due to Saksenaea vasiformis and Apophysomyces elegans.

We report three cases of primary cutaneous zygomycosis due to either Saksenaea vasiformis (two patients) or Apophysomyces elegans (one patient). Extensive surgical debridement helped two patients recover from their infections. The underlying disease in the one patient who died was diabetes mellitus. We reviewed the literature on primary cutaneous zygomycosis and found that S. vasiformis and A. elegans were the etiologic agents in 16 and 13 earlier cases, respectively.

Adult↗

Craniofacial zygomycosis caused by Apophysomyces elegans.

A fatal case of craniofacial zygomycosis caused by Apophysomyces elegans in a 52-year-old man was diagnosed by the presence of broad aseptate, branched hyaline hyphae in tissue from paranasal sinuses and surrounding areas, and isolation of the fungus from the same tissue. The patient suffered from idiopathic myelofibrosis as underlying disease, he was thrombocytopenic and was mildly hyperglycaemic. The infection represents the second case of craniofacial zygomycosis due to A. elegans.

Blood Vessels↗

A new medium for the presumptive identification of dermatophytes.

A new medium, Dermatophyte Identification Medium (DIM) (trade mark pending), was specifically developed to eliminate problems of false-positive results associated with commercially marketed media, such as dermatophyte test medium (DTM). Previous investigations had demonstrated that DTM only partially suppressed growth of nondermatophytes and that several of these nondermatophytic fungi that were morphologically similar to dermatophytes caused false-positive results. Presumptive identification of an unknown isolate as a dermatophyte required only the transfer of a portion of the suspected colony recovered from the specimen to DIM. Positive results, evidenced by a change in the color of the medium, were observed within 24 to 48 h. In studies of over 500 isolates of dermatophytes and common nondermatophyte molds, as well as close to 600 yeast isolates, false-positive results were always associated with bacterial contamination of the mold isolates while false negatives were only observed with occasional isolates of Trichophyton verrucosum. DIM culture was an inexpensive, rapid, and accurate method for the presumptive identification of dermatophytes in the clinical mycology laboratory.

Arthrodermataceae↗

Isolation of Cryptococcus neoformans var. gattii from Eucalyptus camaldulensis in India.

Cryptococcus neoformans var. gattii has an ecological association with five Eucalyptus species: E. blakelyi, E. camaldulensis, E. gomphocephala, E. rudis, and E. tereticornis. After human infections due to C. neoformans var. gattii were diagnosed in the states of Punjab, Himachal Pradesh, and Karnataka, India, a study was undertaken to investigate the association of C. neoformans var. gattii with Indian eucalypts, especially in the state of Punjab. A total of 696 specimens collected from E. camaldulensis, E. citriodora and E. tereticornis (hybrid) trees were examined for the presence of C. neoformans var. gattii. Flowers from two trees of E. camaldulensis in the Chak Sarkar forest and one from the village of Periana near the Ferozepur area yielded five isolates of C. neoformans var. gattii. The origin of the trees could be traced to Australia, thus providing evidence that the distribution of E. camaldulensis correlated with the distribution of human cryptococcosis cases caused by C. neoformans var. gattii in northern India.

Animals↗

An aberrant variant of Histoplasma capsulatum var. capsulatum.

We studied an aberrant culture of Histoplasma capsulatum var. capsulatum isolated from synovial fluid collected from the right elbow of a patient from Kansas. Colonies on Sabouraud glucose agar and other routine mycological media were glabrous to soft, moist, heaped, deeply folded or convoluted, and orange-brown with a white, irregular margin. Microscopically, hyphae were hyaline, septate, and branched and remained totally devoid of conidiation over a period of 2 years on all mycological media. Conversion to the yeast form was achieved on Pine's medium at 37 degrees C. Colonies at early stages of growth were smooth, moist, pasty, shiny, and orange-brown but soon became wrinkled and slightly raised and produced oval, thin-walled cells measuring 2 to 3 by to 4.5 microns which multiplied by polar budding. The identity of the isolate was further confirmed by utilizing the Accuprobe DNA and the exoantigen test for H. capsulatum var. capsulatum.

DNA Probes↗

Maxillary sinusitis caused by Pleurophomopsis lignicola.

An immunocompetent 59-year-old man developed sinusitis over a 6- to 8-month period after cutting down a rotted maple tree (Acer sp.). A polypoid obstruction with a bloody drainage was evident in his right nasal cavity. A computed tomographic scan showed an opacification of the maxillary sinus. Surgery was performed to remove a fungus ball that had extended into the patient's medial sinus cavity. Sections of the sinonasal mucosa revealed marked acute and chronic sinusitis with inflammation, congestion, and hemorrhage. Sections from the pasty brown to black debrided material revealed a fungus ball consisting of an extensive network of brown-pigmented, septate, profusely branched hyphae. When grown on oat agar, the phaeoid fungus produced pycnidia and was identified as Pleurophomopsis lignicola. The genus Pleurophomopsis includes seven species, which are all known from plant material. This report documents for the first time a coelomycetous fungus, P. lignicola, causing sinusitis in an immunocompetent patient.

Fungi↗

Dermatophytes: gross and microscopic.

Dermatophytes, members of the anamorphic genera Epidermophyton, Microsporum, and Trichophyton, are capable of invading keratinous tissue, causing cutaneous infection referred to as dermatophytosis. These species may be anthropophilic, zoophilic, or geophilic based on host preference and natural habitat. These groupings are epidemiologically significant. This article provides a description of the genera and species of the dermatophytes--gross and microscopic--and the tests that may be necessary to confirm their identification.

Arthrodermataceae↗

Chromoblastomycosis caused by Exophiala spinifera.

We report the second case of chromoblastomycosis caused by Exophiala spinifera; this is the first known case in the United States. Examination of biopsied tissue showed thick-walled, internally septated, chestnut brown muriform cells (sclerotic bodies) within multinucleated giant cells present in the dermis that were characteristic of chromoblastomycosis. The individual cells within the muriform cells disarticulated from the outer wall of the parent cell and from each other to form endoconidia within the outer walls of the parent cells. After fracture of the outer walls, the endoconidia were released. This unique process of endoconidial formation in vivo for the propagation of muriform cells was observed for the first time. Initial treatment with itraconazole and 5-fluorocytosine followed by treatment with itraconazole and heat resulted in marked improvement in the patient's lesions. This infection reiterates the fact that the dematiaceous fungus E. spinifera, a well-known etiologic agent of phaeohyphomycosis, can cause more than one type of infection and supports earlier observations that chromoblastomycosis and phaeohyphomycosis represent extremes of a continuum of infections.

Antifungal Agents↗

Brain abscess caused by Schizophyllum commune: an emerging basidiomycete pathogen.

Despite the worldwide distribution and prevalence of Schizophyllum commune, an emerging basidiomycetous pathogen, human infections occur only rarely. We describe the first well-documented pulmonary infection caused by S. commune which disseminated to the brain of a 58-year-old patient undergoing empiric corticosteroid therapy. Magnetic resonance imaging scans revealed ring-enhancing masses. Histologic examination of biopsy tissue from lungs and brain showed hyaline, septate, branched hyphae with clamp connections. Cultures of the lung tissue grew S. commune, which produced numerous, characteristic flabelliform and medusoid fruiting bodies on Czapek's agar. The isolate was susceptible to amphotericin B (MIC, < 0.03 microgram/ml) and fluconazole (MIC, 8 micrograms/ml). Despite treatment with antifungal and antibacterial agents, the patient developed progressive pulmonary failure and bacterial sepsis and died.

Antifungal Agents↗

Occurrence of Penicillium marneffei infections among wild bamboo rats in Thailand.

Penicilliosis marneffei has emerged as an endemic systemic mycosis in Southeast Asia among humans and wild bamboo rats. To gain an insight into the epidemiology of this life-threatening disease, a survey of bamboo rats for natural infections by Penicillium marneffei was carried out in the central plains of Thailand during June-September, 1987. Thirty-one lesser bamboo rats (Cannomys badius) and eight hoary bamboo rats (Rhizomys pruinosus) were trapped. Portions of their internal organs were cultured to determine if they had been infected by P. marneffei. Six each of C. badius (19.4%) and R. pruinosus (75%) yielded cultures of this unique, dimorphic Penicillium species. All of the isolates were readily converted to their unicellular form that multiplies by the process of schizogony by incubating them at 37 degrees C on plates of brain heart infusion agar. Their identity was further confirmed by a specific immunological test. Among the internal organs of the positive rats, the lungs had the highest positivity (83.3%), next in decreased order of frequency were the liver (33.3%) and the pancreas (33.3%). The use and value of domestic and wild animals in locating and demarcating endemic areas of geophilic fungal pathogens are discussed. Penicilliosis marneffei is considered to be a zooanthroponosis--a disease that occurs in lower animals, as well as, humans.

Animals↗

Ovadendron sulphureo-ochraceum endophthalmitis after cataract surgery.

PURPOSE: We examined an 82-year-old woman with delayed-onset endophthalmitis caused by an opportunistic pathogen, Ovadendron sulphureo-ochraceum. METHODS: Tissue obtained during vitrectomy was cultured and examined by light and electron microscopy. An enucleation specimen was examined by light microscopy. RESULTS: The patient had fungal endophthalmitis, with O. sulphureo-ochraceum present in the lens capsule. The eye developed a necrotizing scleritis secondary to O. sulphureo-ochraceum. The patient failed to respond to intravitreous, subconjunctival, and systemic amphotericin B, and the eye was enucleated. CONCLUSION: In this case of O. sulphureo-ochraceum as a human pathogen, the organism caused endophthalmitis after cataract extraction.

Aged↗

Mycoleptodiscus indicus: a new etiologic agent of phaeohyphomycosis.

Mycoleptodiscus indicus, a dematiaceous hyphomycete, was identified as the causal agent of subcutaneous infection in the knee of a 72-year-old male gardener residing in coastal South Carolina. The patient had Wegener's granulomatosis and immunodeficiency. Synovial fluid and biopsy tissue sections from the prepatellar bursa stained with hematoxylin and eosin, periodic acid-Schiff, and Gomori methenamine silver stains revealed branched, septate hyphae and many moniliform hyphal elements. When tissue sections were stained by the Fontana-Masson procedure, melanin pigment in the hyphal cell walls and at the septa was evident. A velvety, dematiaceous mold was isolated from both synovial fluid and the biopsy tissue. Sporulation was induced by exposure of slide cultures on potato dextrose agar to UV light for 12 h at 25 degrees C followed by incubation of the slide cultures at 25 degrees C in the dark for 4 weeks. Clypeate sporodochia consisting of ampulliform, compressed, phialidic conidiogenous cells produced curved, hyaline, one-celled conidia with setulae at one or both ends. Initial treatment with fluconazole for 7 days was not effective, and cultures were positive after treatment. Treatment with amphotericin B with concomitant irrigation and debridement of the affected area followed by treatment with itraconazole resulted in resolution of the infection.

Aged↗

Comparison of three typing methods for clinical and environmental isolates of Aspergillus fumigatus.

To evaluate procedures used for epidemiologic analysis of outbreaks of aspergillosis, we analyzed a collection of 35 Aspergillus fumigatus isolates using three typing methods: isoenzyme analysis (IEA), random amplified polymorphic DNA (RAPD) analysis, and restriction endonuclease analysis (REA). Twenty-one isolates were from a single hospital, with four isolates coming from different patients. Three clinical isolates came from a different hospital, and 11 clinical or environmental isolates were derived from a culture collection. With IEA, the patterns of alkaline phosphatase, esterase, and catalase discriminated nine types. In contrast, 22 types were obtained with five different RAPD primers, and 21 types could be detected with three of these (R108, R151, and UBC90). Restriction endonuclease analysis of genomic DNA, digested with either XbaI, XhoI, or SalI, detected 3, 17, and 13 different REA types, respectively, and 22 types were identified by combining the data from the XhoI and SalI REAs. Twenty-eight types were obtainable with a combination of REA, IEA, and RAPD patterns. Overall, the results pointed to substantial genetic variation among the isolates. Though two isolates had markedly distinct genotypes, their morphologic features and exoantigens were consistent with their being A. fumigatus. The analysis will help in planning epidemiologic studies of aspergillosis.

Aspergillosis↗

Oral histoplasmosis in India: a case report and an overview of cases reported during 1968-92.

Oral histoplasmosis in a 30-year-old male with no history of travel outside India is described. An ulcerating lesion was located on the hard palate. A chest X-ray was normal. Based on physical examination, regional lymph nodes, liver and spleen were not involved. The diagnosis was established by demonstrating yeast-like budding cells in a biopsy of the lesion and by isolating Histoplasma capsulatum in pure culture. The identity of the isolate was confirmed by a chemiluminescent DNA-probe assay and the exoantigen test. A review of the Indian literature from 1968 to 1992 revealed the occurrence of 25 authentic cases of histoplasmosis in India. In 19 cases, lesions were confined to the oral cavity confirming prior observation that histoplasmosis in Indian patients tends to occur primarily in extrapulmonary sites, particularly the oral cavity.

Adult↗

Osteomyelitis of the sternum caused by Apophysomyces elegans.

Apophysomyces elegans, a member of the family Mucoraceae, was found to infect the chest wall and sternum of an immunocompetent man following minor trauma. As in previous cases, amphotericin B therapy alone was inadequate. Extensive surgical debridement was required in order to eradicate the infection.

Aged↗