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I Weitzman

Publications and source records attributed to I Weitzman.

At least 19 recordsLinked to original sources
PubMed1998

A survey of dermatophytes isolated from human patients in the United States from 1993 to 1995.

A survey of dermatophytes, isolated from human patients seeking medical attention, was conducted for the years 1993 to 1995. Data were collected from 23 states throughout the continental United States and the District of Columbia and from 44 to 45 laboratories. These data were compared with the results of two earlier surveys (1979 to 1981 and 1985 to 1987). In contrast to the earlier surveys Trichophyton tonsurans became the most frequently isolated dermatophyte (44.9%) followed by T. rubrum (41.3%), T mentagrophytes (8.5%), Microsporum canis (3.3%) and Epidermophyton floccosum (1.1%). Other dermatophytes were recovered from less than 1%. The increase in T. tonsurans from 27.9% in the 1979 to 1981 survey, to 41.3% in the current survey, accompanied by the decline of T. rubrum from 53.7% to 41.3% is statistically significant (P < .001)

Arthrodermataceae↗
PubMed1998

Invasive Trichophyton rubrum resembling blastomycosis infection in the immunocompromised host.

A 55-year-old renal transplant recipient with onychomycosis and chronic tinea pedis presented with tender nodules on his left medial heel. He then developed papules and nodules on his right foot and calf. A skin biopsy demonstrated periodic acid-Schiff (PAS) positive, thick walled round cells, 2 to 6 microm in diameter, in the dermis. Skin biopsy culture grew Trichophyton rubrum. T. rubrum has been described as an invasive pathogen in immunocompromised hosts. The clinical presentation, histopathology, and early fungal culture growth suggested Blastomyces dermititidis in the differential diagnosis before the final identification of T. rubrum.

Blastomycosis↗
PubMed1998

Incidental finding of Zygomyceteslike hyphae in the placenta. A case report.

BACKGROUND: Zygomycetes is a class of saprophytic fungi causing opportunistic infections. These fungi can cause six distinct clinical manifestations, which can be fatal without rapid diagnosis and treatment. The fungi have a predilection for blood vessel invasion, causing thrombosis, infarction and necrosis of the tissue. CASE: A 25-year-old black woman, a drug abuser, delivered a female infant and the placenta en route to the hospital. The estimated gestational age of the infant was 35 weeks. The infant and mother had an unremarkable hospital course. Evaluation of the placenta revealed extensive involvement of the membranes, umbilical cord and chorionic plate by fungal hyphae without any surrounding inflammation. These hyphae were seen invading blood vessels, but there was no evidence of thrombosis or necrosis. The morphology of the hyphae was consistent with Zygomycetes. The mother was contacted and claimed to be well. CONCLUSION: Only one case of placental involvement by Mucor has been published since 1966. Despite the observation of Zygomyceteslike hyphae in the placenta, both the mother and infant were reported to be doing well.

Adult↗
PubMed1997

In vitro activity of fluvastatin, a cholesterol-lowering agent, and synergy with flucanazole and itraconazole against Candida species and Cryptococcus neoformans.

Fluvastatin, a cholesterol-lowering drug, exhibited minimal activity (MICs of 64 to >128 microg/ml) against Candida species and Cryptococcus neoformans. When fluvastatin was combined with fluconazole or itraconazole, both synergistic and additive effects were noted (fractional inhibitory concentration indices of < or = 0.156 to 0.625; fractional lethal concentration indices of < or = 0.156 to 0.75). This combined fungicidal activity was confirmed by time-versus-killing studies.

Anticholesteremic Agents↗
PubMed1997

Multicenter evaluation of proposed standardized procedure for antifungal susceptibility testing of filamentous fungi.

A multicenter study was conducted to expand the generation and analysis of data that supports the proposal of a reference method for the antifungal susceptibility testing of filamentous fungi. Broth microdilution MICs of amphotericin B and itraconazole were determined in 11 centers against 30 coded duplicate pairs of Aspergillus spp., Fusarium spp., Pseudallescheria boydii, and Rhizopus arrhizus. The effect of inoculum density (approximately 10(3) and 10(4) CFU/ml), incubation time (24, 48, and 72 h), and procedure of MIC determination (conventional and colorimetric [Alamar Blue] evaluation of growth inhibition) on intra- and interlaboratory agreement was analyzed. Based on intra- (97 to 100%) and interlaboratory (94 to 95%) agreement for both drugs, the overall optimal testing conditions identified were determination of colorimetric MICs after 48 to 72 h of incubation with an inoculum density of approximately 10(4) CFU/ml. These testing conditions are proposed as guidelines for a reference broth microdilution method.

Antifungal Agents↗
PubMed1996

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↗
PubMed1995

The dermatophytes.

The etiologic agents of the dermatophytoses (ringworm) are classified in three anamorphic (asexual or imperfect) genera, Epidermophyton, Microsporum, and Trichophyton. Species capable of reproducing sexually belong in the teleomorphic genus, Arthroderma, of the Ascomycota. On the basis of primary habitat association, they may be grouped as geophilic (soil associated), zoophilic, and anthropophilic. Adaptation to growth on humans by most geophilic species resulted in diminished loss of sporulation, sexuality, and other soil-associated characteristics. The dermatophytes have the ability to invade keratinized tissue (skin, hair, and nails) but are usually restricted to the nonliving cornified layer of the epidermis because of their inability to penetrate viable tissue of an immunocompetent host. However, invasion does elicit a host response ranging from mild to severe. Acid proteinases, elastase, keratinases, and other proteinases reportedly act as virulence factors. The development of cell-mediated immunity correlated with delayed hypersensitivity and an inflammatory response is associated with clinical cure, whereas the lack of or a defective cell-mediated immunity predisposes the host to chronic or recurrent dermatophyte infection. Chronic dermatophytosis is mostly caused by Trichophyton rubrum, and there is some evidence that mannan produced by this fungus suppresses or diminishes the inflammatory response. Since dermatophytes cause a communicable disease, modes of transmission and control are discussed as well as a survey of recent trends in therapy. Collection of specimens, culture media, and tests for identification are also presented. Genetic studies have led to an understanding of incompatibility mechanisms, pleomorphism and variation, resistance to griseofulvin, and virulence. Molecular biology has contributed to our knowledge of the taxonomy and phylogenetic relationships of dermatophytes.

Antigens, Fungal↗
PubMed1995

Zygospores: the last word in identification of rare or atypical zygomycetes isolated from clinical specimens.

Three zygomycetes (order Mucorales), isolated from clinical specimens, whose generic or species identification were uncertain, were definitively identified on the basis of the production of zygospores resulting from mating studies. These three isolates were identified as Mucor circinelloides f. circinelloides, Rhizomucor pusillus, and Absidia corymbifera. The production of true zygospores, the "last word" in zygomycete taxonomy, should be considered as a diagnostic tool for the definitive identification of rare, unusual, or atypical heterothallic zygomycetes. Practical considerations, however, limit this method to reference laboratories.

Adult↗
PubMed1994

Differentiation of Nocardia from rapidly growing Mycobacterium species by PCR-RFLP analysis.

The nucleotide sequences from a region of the groEL gene from one Nocardia asteroides and from several species of Mycobacterium were determined and found to be highly homologous. Based on these homologies, we developed a rapid method capable of differentiating between these two genera. The method is based on restriction fragment-length polymorphism (RFLP) analysis of DNA amplified from the groEL gene that is highly conserved between mycobacteria and nocardiae. When the groEL gene from species of these genera is enzymatically amplified by the polymerase chain reaction (PCR), a 422-bp fragment is generated. Correlation of the restriction endonuclease digestion patterns of the amplification products with reference and/or biochemically characterized clinical samples enabled us to establish RFLP profiles for ten species of Mycobacterium and five species of Nocardia. When a portion of the groEL gene from each of these organisms is digested with the restriction endonuclease Hae III, that organism is readily assigned to one of these two genera on the basis of the derived RFLP patterns. The utility of this approach was examined by testing 105 pure cultures from samples previously identified by routine culture techniques for the presence of groEL DNA sequences of mycobacterial or nocardial origin. This analysis correctly identified the organism in all samples tested. In summary, PCR-RFLP analysis provides a rapid and sensitive method for the differentiation of Nocardia species from rapidly growing Mycobacterium species.

Bacterial Proteins↗
PubMed1994

An unusual variant of Trichophyton tonsurans var. sulfureum.

A fungus, recovered from a skin lesion of a patient, produced velvety to powdery, white to deep yellow colonies on Sabouraud glucose agar. Microscopically, it produced a large number of cylindric, smooth-walled, three- to eight-celled macroconidia but failed to produce microconidia on a variety of nutritional media such as rice grains, cornmeal dextrose, potato dextrose, Sabouraud glucose, oatmeal and lactrimel agars. It hydrolysed urea in 7 days, perforated hair in vitro and required thiamine for growth. This isolate represents an atypical variant of Trichophyton tonsurans var. sufureum subvar. perforans.

Culture Media↗
PubMed1993

Catalase-peroxidase gene sequences in isoniazid-sensitive and -resistant strains of Mycobacterium tuberculosis from New York City.

Isoniazid resistance in Mycobacterium tuberculosis is associated with lack of catalase-peroxidase activity. A recent study showed that some isoniazid-resistant M. tuberculosis strains have a complete deletion of the gene (katG) encoding this enzyme. To examine what proportion of clinical isolates of M. tuberculosis have katG deletion, katG sequences in 80 randomly selected isolates from New York City were analyzed. Polymerase chain reaction was used to amplify a 282-bp segment of M. tuberculosis katG and showed that 35 (90%) of 39 isoniazid-sensitive and 31 (76%) of 41 isoniazid-resistant strains contained katG sequences (P > .1). Ten multidrug and high-level isoniazid-resistant strains with identical restriction fragment length polymorphism patterns were also analyzed. All were found to have katG sequences. These findings suggest that mechanisms other than complete deletion of katG are involved in isoniazid resistance among most clinical isolates of M. tuberculosis from New York City.

Base Sequence↗
PubMed1993

Mucor ramosissimus Samutsevitsch isolated from a thigh lesion.

Mucor ramosissimus Samutsevitsch is presented for the first time as an etiologic agent of cutaneous zygomycosis in a patient with aplastic anemia on immunosuppressive therapy. This report also represents the third case caused by this species reported in the literature. A biopsy taken from a lesion on the patient's thigh revealed broad, nonseptate, nonbranching hyphae compatible in morphology with a Zygomycete; M. ramosissimus was cultured twice from the thigh lesion. The patient was treated successfully with amphotericin B. Identifying features of M. ramosissimus include the following: numerous sporangia lacking columellae and resembling those of Mortierella spp., short, erect sporangiophores repeatedly branching sympodially; tough, persistent, and diffluent sporangial walls; numerous oidia in chains; extremely low colonies; and restricted growth at 36 degrees C. This paper describes the isolate and strives to alert the clinical microbiologist to this rarely reported pathogen.

Adult↗
PubMed1985

A comparison between Dactylaria gallopava and Scolecobasidium humicola: first report of an infection in a tortoise caused by S. humicola.

Scolecobasidium humicola, a soil fungus and etiologic agent of phaeohyphomycosis in fish, is herein reported to cause cutaneous lesions in a tortoise, Terrapine carolina var. carolina. S. humicola was isolated from lesions on the foot and dematiaceous hyphae were observed in KOH preparations of the biopsy and in stained preparations. This isolate and others were compared morphologically and physiologically with isolates of Dactylaria gallopava which it resembles. As a result of this investigation, we concluded that D. gallopava may be differentiated from S. humicola macroscopically, by the production in D. gallopava of an extensive diffusible purplish-red to reddish-brown pigment when cultured on Sabouraud dextrose agar; microscopically, by the presence and usually predominance of conidia, whose apical cell is markedly wider than the basal cell, and usually constricted at the septum; and physiologically, by the ability to grow on media containing cycloheximide and by the ability to grow well at 36-45 degrees C. In contrast, S. humicola does not usually produce a diffusible pigment on Sabouraud's dextrose agar or if present, is not extensive; it lacks the wider upper cell; is less constricted or non-constricted at the central septum; grows on media containing cycloheximide, although some inhibition may occur and lastly, does not grow at 36 degrees C or higher. Both species were urease positive, hydrolysed tyrosine but not casein, xanthine, or gelatin.

Animals↗
PubMed1984

Studies in the differentiation between Microsporum ferrugineum Ota and Trichophyton soudanense Joyeux.

A study, conducted with 20 isolates of Microsporum ferrugineum and 12 isolates of Trichophyton soudanense, revealed that some of the discrepancies in the literature regarding their characteristics and differentiation were due to methodology, strain variation and the use of an insufficient number of isolates. We found all isolates of T. soudanense to be urease negative and gelatinase positive (usually by the first week); to produce brown to black colonies on Lowenstein-Jensen medium; to rapidly decompose casein and more slowly tyrosine; to grow well or better at 37 degrees C as compared to room temperature; to produce reflexive branching on cornmeal Tween agar and abundant microconidia on casero medium and to exhibit no sexual reaction with either mating type of arthroderma simii. All but one isolate demonstrated restricted growth on lactose agar and only three isolates perforated hair. In contrast, we found 18 of 20 isolates of M. ferrugineum to be urease positive in urea broth (most isolates were negative on urea agar); all produced light-colored colonies on Lowenstein-Jensen medium; spreading colonies on lactose agar and failed to perforate hair in vitro or to produce reflexive branching. Most isolates manifested poorer to no growth at 37 degrees C compared to room temperature and all but one failed to decompose casein and tyrosine. A few strains produced macroconidia and/or microconidia on casero medium and some reacted sexually with A. simii (a) (-) mating type. Gelatin hydrolysis was variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Culture Media↗
PubMed1984

Phialophora parasitica, an emerging pathogen.

Monoconidial cultures derived from 12 clinical and environmental isolates of Phialophora parasitica were compared with respect to morphologic and physiologic characteristics and response to antifungal agents. No yeast cells were seen in 1- and 3-week-old slide culture preparations. Also, not all of the distinguishing characteristics of this species were displayed by all isolates on all media examined. Although the isolates grew on Sabouraud agar with chloramphenicol and cycloheximide, some inhibition was observed. All cultures were strongly urease-positive and hydrolyzed casein and starch; most decomposed tyrosine but not gelatin. All but one environmental isolate grew well at both 23 and 37 degrees C, but none grew at 40 degrees C. In the sensitivity testing the isolates did not vary much in their response to each drug, although some anomalies were observed. Amphotericin B and miconazole had minimum inhibitory concentrations in the low sensitivity range (2.0-8.0 and 2.5-10 micrograms m-1 respectively), for most isolates, and most isolates were resistant to both 5-fluorocytosine and ketoconazole. Limited observations were made on three other Phialophora species which might be confused with P. parasitica.

Amphotericin B↗