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G St-Germain

Publications and source records attributed to G St-Germain.

12 recordsLinked to original sources
PubMed2001

Prevalence and antifungal susceptibility of 442 Candida isolates from blood and other normally sterile sites: results of a 2-year (1996 to 1998) multicenter surveillance study in Quebec, Canada.

During a 2-year surveillance program (1996 to 1998) in Quebec, Canada, 442 strains of Candida species were isolated from 415 patients in 51 hospitals. The distribution of species was as follows: Candida albicans, 54%; C. glabrata, 15%; C. parapsilosis, 12%; C. tropicalis, 9%; C. lusitaniae, 3%; C. krusei, 3%; and Candida spp., 3%. These data, compared to those of a 1985 survey, indicate variations in species distribution, with the proportions of C. glabrata and C. parapsilosis increasing by 9 and 4%, respectively, and those of C. albicans and C. tropicalis decreasing by 10 and 7%, respectively. However, these differences are statistically significant for C. glabrata and C. tropicalis only. MICs of amphotericin B were > or =4 microg/ml for 3% of isolates, all of which were non-C. albicans species. Three percent of C. albicans isolates were resistant to flucytosine (> or =32 microg/ml). Resistance to itraconazole (> or =1 microg/ml) and fluconazole (> or =64 microg/ml) was observed, respectively, in 1 and 1% of C. albicans, 14 and 9% of C. glabrata, 5 and 0% of C. tropicalis, and 0% of C. parapsilosis and C. lusitaniae isolates. Clinical data were obtained for 343 patients. The overall crude mortality rate was 38%, reflecting the multiple serious underlying illnesses found in these patients. Bloodstream infections were documented for 249 patients (73%). Overall, systemic triazoles had been administered to 10% of patients before the onset of candidiasis. The frequency of isolation of non-C. albicans species was significantly higher in this group of patients. Overall, only two C. albicans isolates were found to be resistant to fluconazole. These were obtained from an AIDS patient and a leukemia patient, both of whom had a history of previous exposure to fluconazole. At present, it appears that resistance to fluconazole in Quebec is rare and is restricted to patients with prior prolonged azole treatment.

Amphotericin B↗
PubMed2001

Impact of endpoint definition on the outcome of antifungal susceptibility tests with Candida species: 24- versus 48-h incubation and 50 versus 80% reduction in growth.

The growth inhibition patterns of 764 clinical yeast isolates, in response to amphotericin B, flucytosine, itraconazole and fluconazole, were studied in order to determine the frequency of trailing growth and any impact this, as well as 24- or 48-h incubation periods, may have on minimum inhibitory concentration (MIC) results. A broth microdilution method following National Committee for Clinical Laboratory Standard No. M27A recommendations was used. Trailing growth was observed mainly with azoles. Furthermore, over 98% of isolates exhibiting a trailing effect at 24 h with fluconazole and itraconazole were either Candida albicans or Candida tropicalis. When comparing 24- and 48-h IC50 values, discrepancies were observed with itraconazole and fluconazole, respectively, in 18 and 11% of C. albicans and 24 and 30% of C. tropicalis. When comparing IC50 and IC80 values at 24 h, discrepancies were again essentially seen with itraconazole and fluconazole, respectively, in 11 and 10% of C. albicans, and 17 and 27% of C. tropicalis. In susceptibility tests performed with a microdilution method and read spectrophotometrically, 48-h IC80 values result in an unlikely high number of resistant isolates, indicating that a 24-h incubation and a 50% reduction in optical density may correlate better with clinical outcome.

Antifungal Agents↗
PubMed1995

Ketoconazole and itraconazole susceptibility of Candida albicans isolated from patients infected with HIV.

Two hundred and fifty-five isolates of Candida albicans were collected from 93 patients infected with HIV during the course of a clinical trial comparing ketoconazole with itraconazole for the treatment of oropharyngeal or oesophageal candidosis. The susceptibility of the isolates to both drugs was determined by incubating 0.5-2.0 x 10(4) CFU/mL yeast in 0.25-16 mg/L drug in RPMI1640 buffered with MOPS for 24 h at 35 degrees C in 5%CO2 in microtitre trays. Each plate was agitated before reading the optical density. The IC90, IC80 and IC50 were defined as the lowest drug concentration to reduce the optical density to > or = 90%, 80% and 50% of the growth control respectively. IC90S > 0.25 mg/L of ketoconazole and/or itraconazole were found for 42 isolates recovered from 21 patients, 12 of whom had responded to treatment. IC80S > 0.25 mg/L were found for only six of these isolates which had been recovered from three patients, two of whom responded well to treatment. These results indicate that neither the IC90 nor the IC80 are useful in predicting clinical resistance. None of the isolates exhibited IC50 > 0.25 mg/L to either drug which is consistent with the low incidence of resistance reported for these antifungal agents.

AIDS-Related Opportunistic Infections↗
PubMed1993

Infection due to Rhizomucor pusillus: report of four cases in patients with leukemia and review.

Rhizomucor pusillus, a thermophilic fungus of the order Mucorales, is a rare cause of human infection. A search of the literature has produced only seven reports describing nine cases of infection caused by this organism. Recently, over a period of 17 months, four cases of R. pusillus infection in patients with leukemia were diagnosed: a cluster of three cases in a Montreal hospital and one isolated case from Quebec City. All four cases were proven both by histopathologic examination and by culture of tissues. In three cases, pulmonary involvement was confirmed following lung surgery, and in one case, disseminated infection was observed at autopsy. All patients received amphotericin B, and two underwent surgical debridement; however, none of the patients survived.

Adolescent↗
PubMed1990

Effects of pentamidine alone and in combination with ketoconazole or itraconazole on the growth of Candida albicans.

The in vitro interaction of pentamidine with ketoconazole and with itraconazole was studied with 10 strains of Candida albicans isolated from acquired immunodeficiency syndrome patients and one azole-resistant strain. Although growth curves indicated that concentrations of 1 microgram or more of pentamidine per ml significantly inhibited the growth of C. albicans, MICs and minimum fungicidal concentrations (MFCs) were greater than or equal to 10 micrograms/ml. Combinations of ketoconazole and pentamidine did not appear to have any significant effect on MICs or MFCs with most strains. However, the azole-resistant strain exhibited a 2-log decrease in MIC when exposed to ketoconazole combined with 1.0 microgram or more of pentamidine per ml. Similar results were obtained with itraconazole. An Eagle, or paradoxical, effect was observed with four strains exposed to itraconazole alone and in combination with 0.01 and 0.1 microgram of pentamidine per ml. This effect was not seen when concentrations of pentamidine reached 1.0 microgram/ml. Although no fungicidal effect was observed with any of these drugs alone, itraconazole combined with 10 micrograms of pentamidine per ml was fungicidal for eight strains. No signs of antagonism between pentamidine and these two antifungal agents were observed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Collaborative evaluation of antigen detection by a commercial latex agglutination test and enzyme immunoassay in the diagnosis of invasive candidiasis.

The Cand-Tec Candida detection system and enzyme immunoassay for serum mannan were retrospectively compared in a controlled collaborative evaluation of antigen detection in 32 patients with candidiasis proven by biopsy or culture from a normally sterile site and with sera drawn within 7 days of inclusion. With a threshold titer of 1/8, which excluded false-positive results in 17 hospitalized patients without candidiasis, sensitivities for all 32 patients with candidiasis were 44% for the Cand-Tec assay and 17% for the enzyme immunoassay. Both assays provided greater sensitivity when sera were drawn within 24 h of inclusion in the study and in the category of patients with invasive candidiasis (57% by Cand-Tec and 33% by enzyme immunoassay). The Cand-Tec assay gave false-positive results (titer, greater than or equal to 1/8) in 4 of 6 patients with transient candidemia, in 1 of 20 otherwise healthy patients with rheumatoid factor, and in 1 patient with a positive cryptococcal latex agglutination test. Three serum specimens from 3 of 32 patients with candidiasis contained rheumatoid factor and gave titers of greater than or equal to 1/8 by the Cand-Tec assay. Detection of serum mannan by enzyme immunoassay was less sensitive but more specific than the Cand-Tec Candida detection system for the diagnosis of invasive candidiasis.

Antigens, Fungal↗
PubMed1989

Performance characteristics of two bioassays and high-performance liquid chromatography for determination of flucytosine in serum.

We compared the accuracy and precision of two microbiological methods and one high-pressure liquid chromatography (HPLC) procedure used to measure the concentrations of flucytosine in serum. On the basis of an analysis of six standards, all methods were judged reliable within acceptable limits for clinical use. With the biological methods, a slight loss of linearity was observed in the 75- to 100-micrograms/ml range. Compared with the bioassays, the HPLC method did not present linearity problems and was more precise and accurate in the critical zone of 100 micrograms/ml. On average, results obtained with patient sera containing 50 to 100 micrograms of flucytosine per ml were 10.6% higher with the HPLC method than with the bioassays. Standards for the biological assays may be prepared in serum or water.

Biological Assay↗
PubMed1986

Torulopsis candida, a new opportunistic pathogen.

We described the first documented case of intravenous-catheter-associated fungemia caused by Torulopsis candida (Candida famata). The microorganism was isolated from two blood cultures and one intravenous catheter tip in a bone marrow transplant patient. Both the intravascular cannula and the immunological status of the patient are believed to have played major roles in predisposing the patient to such an infection. Uneventful recovery occurred after the removal of the catheter and amphotericin B therapy.

Adult↗
PubMedDate not supplied

Effect of media on growth rate and susceptibility testing of Cryptococcus neoformans.

The effect of four media or media combinations on the growth and the in vitro susceptibility to amphotericin B, 5-fluorocytosine, fluconazole and itraconazole of 51 isolates of Cr. neoformans was studied. The drug concentration producing a 50% decrease in OD405 (IC50) was determined in microtiter format. The following MOPS buffered media or media combinations (antifungal drug diluent/inoculum diluent) were used: RPMI 1640 (RPMI)/RPMI, Yeast nitrogen base (YNB)/YNB, RPMI/YNB and RPMI/High resolution broth. Amphotericin B was further tested in M3 broth in the microdilution format and on RPMI agar with the E-test. Growth rates (OD405) were higher in YNB, RPMI/YNB, RPMI/HR and M3 as compared to RPMI alone. After 48 h of incubation, IC50 values obtained with RPMI alone and with RPMI/YNB correlated within two dilutions for 98, 95, 95 and 100% of test strains with amphotericin B, 5-fluorocytosine,fluconazole and itraconazole respectively. The E-test provided the widest range of IC values with amphotericin B. Growth of Cr. neoformans can be enhanced in susceptibility tests using microtiter plates with drugs diluted in RPMI by preparing the inoculum in YNB. However, when using spectrophotometric endpoint determinations, sufficient growth is obtainable with most isolates for test interpretation at 48 h in RPMI alone.

Amphotericin B↗