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Biomedical subjects

A S Sekhon

Publications and source records attributed to A S Sekhon.

At least 19 recordsLinked to original sources
PubMed1997

Usefulness of a microimmunodiffusion test for the detection of Penicillium marneffei antigenemia, antibodies, and exoantigens.

Eight sera from culturally-proven cases of penicilliosis marneffei and their corresponding isolates were examined for circulating antibody(ies) and antigen, and exoantigens, respectively, using a microimmunodiffusion (MID) test. Two of the 8 sera produced strong precipitins (1-2) when reacted against control Penicillium marneffei antigen (5-week-old shaken cultures at 25 C) in the presence of control rabbit anti-P. marneffei serum. Five of the 8 sera produced a strong precipitin line when reacted against control hyperimmune serum to P. marneffei. These five sera, and one additional serum, which tested negative for antibody to P. marneffei, demonstrated the presence of antigen by reacting only against the anti-P. marneffei serum. Serological evaluations of the sera revealed that the MID test is capable of detecting antibody and antigen in AIDS patients having penicilliosis marneffei infections. Exoantigen analysis of the 8 P. marneffei isolates, which were previously identified using the conventional and time-consuming macro- and micro-morphological characteristics, showed the presence of 1 to 4 specific exoantigens in MID. With the exoantigen analysis, the identity of all of the isolates was confirmed as P. marneffei. Our studies indicated that the serological tests are useful for detecting circulating antibody and/or antigen in patients' sera, and that the exoantigen test is reliable for confirming the identity of P. marneffei cultures.

AIDS-Related Opportunistic Infections↗
PubMed1997

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↗
PubMed1996

Hyalohyphomycosis caused by Paecilomyces variotii in an obstetrical patient.

A case of hyalohyphomycosis, caused by Paecilomyces variotii, has been described in a 31-year-old female, who had undergone a cesarean section in her 39th week of pregnancy for a trial of labour. Five days following delivery, she complained of sharp, cramp-like pains, localized to the incisional site. She became febrile (38.2 degrees C). An ultrasound examination revealed a complex mass and fluid within the pelvis and upper abdomen. The fluid was drained by a needle aspiration and the patient was administered a regimen of antibacterial drugs. Microscopic examination did not reveal any bacteria in a gram stained preparation and cultures were negative as well. However, the fluid demonstrated a few segments of septate, hyaline hyphae, with cultures yielding a pure growth of P. variotii. An exoantigen procedure, currently under development, was helpful in confirming the identity of the patient's fungus. The patient's condition improved following needle aspiration and her recovery was uneventful. It is reiterated that certain infections, attributed to low-grade opportunistic pathogens, such as P. variotii, may be cured by proper surgical drainage.

Adult↗
PubMed1995

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↗
PubMed1995

Comparative evaluation of commercial Premier EIA and microimmunodiffusion and complement fixation tests for Coccidioides immitis antibodies.

A total of 409 serum and cerebrospinal fluid specimens from human subjects with proven coccidioidomycosis, with other infections, or with no apparent illness were tested for antibodies to Coccidioides immitis by the Premier EIA (Meridian Diagnostics, Inc., Cincinnati, Ohio), which tests for immunoglobulin G (IgG) and IgM responses to coccidioidal antigens, and by the conventional complement fixation (CF) or immunodiffusion (ID) assays for antibodies corresponding to those detected by the tube precipitin (TP) or CF tests. Of the 409 specimens, 47 were from persons with confirmed coccidioidomycosis and all were positive for C. immitis antibodies in IDCF tests and enzyme immunoassays (EIAs) for both IgG and IgM. The EIA for detecting both IgG and IgM antibodies proved to be sensitive for detecting coccidioidomycosis case sera positive by the IDCF, IDTP, and CF tests. Maximal sensitivity for diagnosing coccidioidomycosis is dependent upon detection of both IgG and IgM antibodies in the EIA. The EIA, however, was not absolutely specific, since some sera from patients with confirmed blastomycosis and some from patients with noncoccidioidal disease produced false-positive reactions.

Antibodies, Fungal↗
PubMed1994

Pulmonary penicillosis marneffei: report of the first imported case in Canada.

A 57-year-old female, born in Laos and who had lived in Thailand prior to immigrating to Canada in 1989, was seen by her physician with a chief complaint of cough and dyspnea. Her chest X-ray showed bilateral pulmonary air fluid levels. A fungus, with a diffusible red pigment, tentatively identified as Penicillium marneffei, was isolated from the patient's bronchial washings and sputum specimens. At 37 degrees C, the fungus converted to a yeast form when cultured on brain heart infusion agar. Microscopic examination of this culture revealed yeast cells that reproduced by fission. The identity of the patient's isolate was confirmed as P. marneffei with an exoantigen test. The patient's serum demonstrated specific antibodies to P. marneffei antigen. Treatment with amphotericin B and ketoconazole resulted in clinical improvement, clearing of chest X-rays and conversion to sero-negativity. Our case is the first recorded diagnosis of imported penicillosis marneffei in Canada. The minimal inhibitory concentrations recorded for the patient's isolate to fluconazole, 5-fluorocytosine, itraconazole and miconazole were 12.5, 0.39, < 0.195 and < 0.195 micrograms/ml, respectively.

Amphotericin B↗
PubMed1993

The prevalence of congenital orthopaedic anomalies in a rural community.

A rural Indian population of 50,055 was studied for the detection of congenital orthopaedic anomalies by a door-to-door survey. An incidence of 2.25 cases per 1000 population was found. Club foot was the commonest anomaly at 0.9 per 1000, followed by polydactyly and syndactyly at 0.45 and 0.38 cases per 1000. The most common anomaly found in females was a congenital short 4th metatarsal (0.24 per 1000).

Bone and Bones↗
PubMed1993

In vitro susceptibility of mycelial and yeast forms of Penicillium marneffei to amphotericin B, fluconazole, 5-fluorocytosine and itraconazole.

The mycelial (25 degrees C) and yeast-like (37 degrees C) forms of Penicillium marneffei clinical and type strains were investigated for their in vitro susceptibility to amphotericin B (AmB), 5-fluorocytosine (5-FC), fluconazole (FLU) and itraconazole (ITZ), using Bacto antibiotic medium 3, yeast-nitrogen, Sabouraud's dextrose (pH 5.7) and high resolution (pH 7.1) broth media (1ml/tube), respectively. Results indicated that the minimal inhibitory and minimal fungicidal concentrations (MICs and MFCs) for the mycelial cultures of P. marneffei to AmB were in the range 0.78-1.56 and 0.78-3.125 micrograms/ml, respectively, as against 3.125-25 micrograms (MICs) for the yeast form cultures. The MFCs to AmB for the yeast form were one dilution higher. The MICs to FLU were generally lower for the yeast form (6.25-25 micrograms) than the mycelial form (25-50 micrograms/ml), whereas MFCs for the mycelial cultures were > 100 micrograms as compared to 6.25-100 micrograms for their yeast form. The MICs for the mycelial form to 5-FC ranged from < 0.195-0.39 microgram. Higher MICs (6.25 micrograms) were recorded for their yeast form. The MFCs to 5-FC for the yeast form were 25-100 micrograms/ml. The MICs for the mycelial form to ITZ ranged from < 0.195 to 3.125 micrograms/ml. Higher values (< 0.195-50 micrograms) were recorded for their yeast-like form. The MFCs to ITZ for mycelial and yeast forms ranged from < 0.195-0.39 and 25-100 micrograms/ml, respectively. Results indicate that P. marneffei's yeast form is more sensitive to FLU and ITZ (8 of 10 strains) while the mycelial form displayed greater susceptibility to AmB and 5-FC. The MICs for ITZ remained steady in SD medium, pH 5.7 to 7.1. However, some strains gave higher MIC values (0.39-1.56 micrograms/ml) when tested in the HR.

Amphotericin B↗
PubMed1992

Hansenula anomala fungemia in an infant with gastric and cardiac complications with a review of the literature.

A 6-month-old female infant, with a birth weight of 2.74 kilograms, was born with multiple congenital abnormalities, including gastric and gastrointestinal defects. She was admitted to the hospital with hematemesis. The patient could not be fed orally, and parenteral nutrition was initiated through a central venous catheter. Following pyloroplasty, she developed superior vena cava syndrome, renal disfunction and episodes of sepsis. Stool and respiratory specimens were negative for fungi, but four blood cultures yielded Hansenula anomala var. anomala. Cultures for fungi from intravenous catheter tips were negative. The baby was treated with amphotericin B (am B) and 5-fluorocytosine (5-FC), (amB; 0.1 mg/kg body weight and 5-FC, 100 mg, q.i.d.). The minimal inhibitory concentrations of am B, 5-FC, am B + 5-FC (1:1, w:w) and fluconazole to H. anomala were 1.56, less than 0.195, 1.56, and 1.56 micrograms, respectively. Following antifungal therapy and removal of the catheter, the patient tolerated oral feeding and, at the time of discharge, her weight had increased to 4.91 kg. This report records H. anomala as an opportunistic yeast pathogen for the first time in Alberta, Canada. Previously published cases of H. anomala infections are reviewed.

Abnormalities, Multiple↗
PubMed1992

Cerebral phaeohyphomycosis caused by Xylohypha bantiana, with a review of the literature.

A 76-year-old male with chief complaints of back and right leg sciatica was hospitalized. His abdominal CT scan revealed lumber spondylitic stenosis. A laminectomy was performed. Postoperatively, he became febrile, aphasic and had grand mal seizure. A left craniotomy of the front abscess, seen in the CT scan, was performed. H and E stained smears of drainage revealed dematiaceous, septate hyphae. Cultures of the abscess drainage grew an olivaceous-grey fungus. Based on macro- and micro-morphological characters, growth at 42 degrees C, and exoantigenic analysis, the patient's fungus was identified as Xylohypha bantiana. Treatment with amphotericin B and 5-fluorocytosine was initiated. Despite surgical procedures and antifungal therapy, the patient's condition deteriorated and he died a few weeks later due to cerebral edema. The case reported here is the first microscopically, culturally, histopathologically and exoantigenically proven case of phaeohyphomycosis caused by X. bantiana in the province of Alberta and from Canada. A review of the literature on cases of X. bantiana infections has also been presented.

Adolescent↗
PubMed1992

In vitro sensitivity of Penicillium marneffei and Pythium insidiosum to various antifungal agents.

Ten isolates of Penicillium marneffei and eight of Pythium insidiosum were tested for their in vitro sensitivity to amphotericin B, hamycin (a polyene heptaene), two water-soluble analogs of amphotericin B and hamycin, namely, JAI-Amb, and JAI-hamycin,5-fluorocytosine, fluconazole, itraconazole,ketoconazole and miconazole. Itraconazole manifested the strongest activity against all of the 10 isolates of P. marneffei and would be the drug of choice in the treatment of penicilliosis due to P. marneffei. The polyene antibiotics amphotericin B and hamycin and their water-soluble analogs showed no appreciable activity against P. insidiosum. Pytium insidiosum isolates were sensitive to fluconazole, ketoconazole, and miconazole. Miconazole exhibited the strongest in vitro activity against all of the 8 isolates of P. insidiosum, followed by ketoconazole.

Antifungal Agents↗
PubMed1992

Evaluation of the Pro-Lab ID ring system for the identification of medically important yeasts.

We evaluated 151 coded isolates of medically important yeast species belonging to the genera Candida, Cryptococcus, Geotrichum, Rhodoturula, Saccharomyces and Torulopsis using the newly developed rapid Pro-Lab Identification Ring, PL 960 system (PLID-Ring). All isolates were concurrently identified by the API 20C and conventional procedures comprising macro- and micromorphology, assimilation and fermentation of various carbon and nitrogen compounds. The PLID-Ring system identified isolates of Candida albicans, C. kefyr, C. krusei, C. lusitaniae, C. parapsilosis, Rhodotorula rubra, and Torulopsis glabrata with 100% accuracy in 24 h. This system identified C guilliermondii and S. cerevisiae isolates with an accuracy of 90% and 86%, respectively, while those belonging to Cr. neoformans, T. candida (= C. famata), C. rugosa and C. tropicalis were identified with 38.4%, 50%, 12.5% and 50% accuracy, respectively. Three isolates of Cr. laurentii were not identified by the PLID-Ring system. The overall accuracy of the PLID-Ring system was 81.45% (123 of 151 isolates). However, the system does not include species such as Cr. laurentii in its data base. When these three Cr. laurentii isolates were excluded from the evaluation, the accuracy of the PLID-Ring system increased from 81.45% to 83.1%.

Candida↗
PubMed1992

Effects of culture media on the in vitro susceptibility of selected opportunistic fungi to fluconazole and itraconazole.

The sensitivity of 23 isolates of opportunistic fungi, Aspergillus fumigatus (5), A. flavus (5), A. niger (5), Pseudallescheria boydii (5), Alternaria alternata (2) and Xylohypha bantiana (1), was investigated against fluconazole and itraconazole, using Sabouraud's dextrose broth (SD) and a high-resolution (HR) medium (Pfizer, Inc.). The procedure followed was a standard tube dilution (1 ml/tube) method. Candida albicans Y01 09 was included as reference strain to monitor quality and reproducibility. Results indicated that the minimal inhibitory concentrations (MICs) of fluconazole for all Aspergillus spp. and C. albicans were greater than or equal to 100 micrograms/ml in SD medium, whereas, for P. boydi, A. alternata and X. bantiana, the MICs were 50 micrograms/l. The MICs of itraconazole in SD medium were less than 0.195-1.56 micrograms/ml for the fungi tested. In HR medium, the MICs of fluconazole for the Aspergillus spp, were greater than or equal to 100 micrograms/ml, and those for P. boydii, A. alternata and X. bantiana were 0.78, 50 and 50 micrograms/ml, respectively. The MICs of itraconazole for all fungi ranged from less than 0.198 to 0.78 micrograms/ml in the HR medium. The values for the reference strain were 1.56 and 100 micrograms/ml in the HR medium for fluconazole and itraconazole, respectively. The HR medium was more suitable for testing P. boydii against fluconazole. This culture medium did not appear to significantly affect the MICs of itraconazole as compared to those of fluconazole, for the fungi investigated.

Alternaria↗
PubMed1992

In vitro activity of amphotericin B, hamycin and their novel water-soluble compounds against pathogenic yeasts.

Twenty-eight pathogenic isolates, 4 each of Candida albicans, C. lusitaniae, C. parapsilosis, Cryptococcus neoformans, Torulopsis glabrata and Trichosporon beigelii were tested for their in vitro sensitivity to amphotericin B (AmB), hamycin (HA) and their novel water-soluble compounds, namely JAI-AmB (oral and injectable; patents pending) and JAI-HA (Jaimycin Inc., Walnut Creek, Calif., USA), using a standard double-dilution broth (1 ml/tube) procedure. The 2 novel compounds, namely JAI-AmB and JAI-HA, contain one twenty-fifth (w/w) of the AmB and HA, respectively. Results showed that the minimal inhibitory concentrations (MICs) of AmB for all species, except C. lusitaniae and Tr. beigelii (3.125-6.25 micrograms/ml), were 0.195-1.56 micrograms/ml. The values of JAI-AmB (oral) for C. albicans, C. parapsilosis, Cr. neoformans and To. glabrata ranged from 0.78 to 25 micrograms/ml. The MICs of JAI-AmB (oral) for the other yeasts were 100 micrograms/ml. All of the yeasts yielded higher MICs (3.125-100 micrograms/ml) against JAI-AmB (injectable) than the JAI-AmB (oral) preparation. Except for C. parapsilosis (MICs 25-100 micrograms/ml), all of the other species showed greater sensitivity to the parent HA (0.195-100 micrograms/ml) than AmB. The values for JAI-HA ranged from 0.195 to 100 micrograms/ml for all isolates, except C. tropicalis (100 micrograms/ml). Based on our in vitro findings, in vivo efficacies of JAI-AmB and JAI-HA should be carried out.

Amphotericin B↗
PubMed1991

Review of human and animal cases of coccidioidomycosis diagnosed in Canada.

The first Canadian case of coccidioidomycosis in a human was reported in 1952 and 11 more cases since then. This study provides details of other cases of coccidioidomycosis that have been diagnosed in Canada. Based on clinical details, isolation of Coccidioides immitis, detection of a specific antibody (F band) for coccidioidomycosis by macro- or microimmunodiffusion tests, concurrently used with the complement fixation procedure, and histopathological findings, 116 more cases of this disease were verified. The great majority (94%) of these cases were diagnosed in the western Canadian provinces of British Columbia, Alberta, Saskatchewan and Manitoba, and the others in Quebec, Ontario and Nova Scotia (5, 1, and 1 cases, respectively). Available information indicates that the C. immitis infections were contracted during visits to endemic areas in the United States (Arizona, California and New Mexico), Mexico, and Bolivia. Pulmonary infections were the most common type of coccidioidomycosis (93%) followed by the disseminated or meningeal types C. immitis infections occurred in individuals with or without predisposing factor(s) and were more common in males than in females. The exoantigen procedure was very useful and reliable in the accurate and rapid identification of suspected C. immitis isolates. Two cases of coccidioidomycosis were reported in animals in Ontario, Canada.

Aged↗
PubMed1990

Current status of cryptococcosis in Canada.

The concurrent use of microscopic, cultural, histopathologic and immunologic procedures enabled us to diagnose 91 cases of cryptococcosis, belonging to cutaneous, pulmonary, meningeal and disseminated types, from the time this mycosis was first reported in Canada in 1953 to the present. These cases occurred predominantly in Quebec (43%) followed by Alberta, British Columbia, Ontario, Saskatchewan, Manitoba, New Brunswick and Newfoundland. It is not known whether any Cryptococcus neoformans infections have occurred elsewhere in Canada. The clinical and laboratory findings indicate that infections occurred in debilitated as well as nondebilitated individuals. Nearly 25% of the infections were seen in individuals having the acquired immune deficiency syndrome (AIDS) in provinces of Alberta, British Columbia, Ontario and Quebec. In some of the AIDS cases, the latex agglutination (LA) test demonstrated exceptionally high titres of circulating cryptococcal antigen (1:256 to 1:32,768). Cr. neoformans infections occurred more commonly in males than in females, and there were 11 fatal cases of cryptococcosis. The incidence of Cr. neoformans in Canada is probably higher than our data suggest because cryptococcosis is not notifiable in Canada and underreporting is likely.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Antigenic relationship of Dactylaria gallopava to Scolecobasidium constrictum.

Dactylaria gallopava and Scolecobasidium constrictum were reduced to varietal status under the new combination of Dactylaria constricta (Abbott) Dixon et Salkin var. gallopava (Cooke) Salkin & Dixon, and D. constricta (Abbott) Dixon et Salkin var. constricta, primarily on the basis of the morphologic similarity of their two-celled, dematiaceous, blastic conidia. To appraise this taxonomic change, we studied the antigenic relationship of D. gallopava to S. constrictum using the exoantigen procedure. Exoantigens were prepared from 20 isolates of D. gallopava, seven isolates of S. constrictum and two isolates of S colecobasidium tschawytschae and were tested against reference rabbit anti-D. gallopava and anti-S. constrictum antisera in the presence of their homologous antigens using the micro-immunodiffusion technique. All D. gallopava isolates produced two to three distinct, identical exoantigens. The seven isolates of S. constrictum also produced two to three distinct exoantigens. None of the seven isolates of S. constrictum was reactive against the D. gallopava reference system. Three of the 20 D. gallopava culture filtrate antigens produced one or two precipitin bands of nonidentity with the S. constrictum reference reagents. Both isolates of S. tschawytschae were nonreactive with the D. gallopava and S. constrictum reference reagents. In addition, D. gallopava differed from S. constrictum in the production of a reddish-brown diffusible pigment, growth up to 45 degrees C, and sensitivity to cycloheximide. Based on these physiologic differences and little or no antigenic relatedness between D. gallopava and S. constrictum, we conclude that these two species should be retained as separate entities rather than be considered as varieties of a single species.

Animals↗