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Biomedical subjects

A K Garg

Publications and source records attributed to A K Garg.

At least 19 recordsLinked to original sources

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

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

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

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

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

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

Pyogenic pericarditis in a patient with burns--a rare complication.

We report a patient with 60 per cent of the body surface area burned who developed pyogenic pericarditis which was treated successfully by open pericardial drain. In an estimated 1000 patients with burns treated in this hospital over a period of 5 years from 1984 to 1989, this is the first patient developing pyogenic pericarditis. A possible pathological basis for the sequence of events is discussed.

Adult

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

Effect of proteoglycans on type I collagen fibre formation.

Collagen fibrillogenesis is a multistep process involving assembly of molecules into fibrils and bundles of fibrils. The exact role of proteoglycans in collagen fibrillogenesis is unclear. The purpose of these studies is to study the effect of proteoglycans on collagen fibrillogenesis in vitro. Results of these studies suggest that the proteoglycans dermatan sulphate and chondroitin sulphate do not change the final turbidity and hence the diameter of fibrils formed during the early stages of fibrillogenesis. This suggests that proteoglycans may not influence the early phases of collagen assembly, such as nucleation. However, proteoglycans added during the final stages of collagen fibre formation in vitro cause changes in ultimate tensile strength. In the presence of the high-molecular-weight proteoglycan, the ultimate tensile strength is increased by a factor of 1.5 above that of the control, whilst in the presence of low-molecular weight chondroitin sulphate proteoglycan the tensile strength is significantly decreased. It is concluded that proteoglycans influence the later stages of fibre formation. The presence of high-molecular-weight chondroitin sulphate proteoglycan leads to efficient stress transfer between collagen fibrils, altering the ultimate tensile strength. The results of these studies will be useful in optimizing the design of collagen tendon-ligament prostheses.

Animals

Antigenic relationship of Penicillium marneffei to P. primulinum.

Penicillium marneffei (ATCC 24100) was first isolated from a naturally acquired human infection in the U.S.A. by DiSalvo et al. in 1973. In 1979, this isolate was studied by Pitt who reidentified it as Penicillium primulinum. This prompted us to examine the antigenic relationship between P. marneffei and P. primulinum by comparing their exoantigens. The antigenic relationships of 11 isolates, including the type strains of P. marneffei and P. primulinum, were examined. Each exoantigen extract was tested simultaneously against rabbit anti-P. marneffei and P. primulinum antisera in the presence of the appropriate reference antigens. All eight isolates of P. marneffei, including ATCC 24100, produced two to four specific precipitin lines against their homologous antiserum. However, four of the eight extracts cross-reacted with unabsorbed antiserum to P. primulinum. The P. primulinum extracts contained specific exoantigens which only reacted with the anti-P. primulinum antiserum. Non-specific cross-reactions were eliminated by absorption procedures. On the basis of the specific exoantigens produced by both species, P. marneffei and P. primulinum were found to be antigenically distinct. Isolate ATCC 24100 was shown to be closely related to the other P. marneffei isolates and distinct from P. primulinum. Our results confirm the original identification of ATCC 24100 as P. marneffei and not P. primulinum as Pitt had concluded.

Antigens, Fungal