[Systemic yeast infections in a general hospital. Correlation between study of susceptibility in vitro and patient survival to the fungal infection episode]. / Infecciones sistémicas por levaduras en un hospital general. Correlación entre estudio de susceptibilidad in vitro y supervivencia de los pacientes al episodio de infección fúngica.

BACKGROUND: Fungi are important causal agents of nosocomial infections, that usually have high mortality rates. AIM: To evaluate the species distribution and susceptibility patterns of deep yeast infections in a General Hospital and to correlate those results with patient survival. MATERIAL AND METHODS: Twenty one strains (from five pediatric and 16 from adult patients) were studied. Antifungal Susceptibility Testing (AST) to Amphotericin B (Anfb), Fluorocytosine (5FC), Fluconazole (FZ) and Itraconazole (IZ) was performed according to the EUCAST document. Clinical data of patients was obtained and survival to the infection was recorded. RESULTS: C. albicans was isolated in 11 samples (52%), C. parapsilosis in three samples (14%), C. glabrata in two samples (9%), C. tropicalis in one sample (5%) and C. neoformans in four samples (19%). Twenty three percent of fungi were recovered at the Surgical Intensive Care Unit. The MICs ranged between 0.25 and 0.5 microgram/mL for Anfb; between 0.25 and 16 micrograms/ml for SFC, between 0.12 and 32 micrograms/mL for FZ and 0.015 and 0.5 microgram/mL for IZ. No association between antifungal susceptibility and patient survival was observed. CONCLUSIONS: C. albicans continues to be the most frequently isolated yeast, however, non-albicans species are an emergent group causing nosocomial infections. Surgical procedures are the main source of fungal infections in this sample.

Treatment of Absidia corymbifera infection in mice with amphotericin B and itraconazole.

The activities of amphotericin B and itraconazole were studied in a temporarily neutropenic murine model of disseminated Absidia corymbifera infection, caused by two different strains. Amphotericin B MICs were 0.25 mg/L for both strains and itraconazole MICs were 1 and 2 mg/L. Amphotericin B was effective in vivo with both isolates. Itraconazole was less effective.

Change in fluconazole susceptibility patterns and genetic relationship among oral Candida albicans isolates.

OBJECTIVE: To assess the genetic homogeneity or heterogeneity within each set of Candida albicans isolates colonizing/infecting the oral cavities of HIV-infected patients undergoing azole therapy when changes in susceptibility to fluconazole were detected. DESIGN: Fourteen HIV-positive patients suffering recurrent episodes of oral candidosis were prospectively followed from the first episode to the isolation of strains with decreased susceptibility to fluconazole. The strains of C. albicans isolated either from episodes or controls throughout the prospective study were analysed. METHODS: Electrophoretic karyotyping and hybridization with the repeated sequence probe 27A were used to delineate sequential isolates. In vitro susceptibility tests to fluconazole and ketoconazole were also performed. The results obtained by DNA fingerprinting with the probe combined with computer-assisted analysis were used to assess the genetic relationships amongst the strains. In addition, comparison with the genetic relatedness of a group of geographically unrelated strains was made. RESULTS: Isogenic populations of sequential isolates were observed only in two patients; 12 patients harboured heterogenic populations over time, although in 11 patients there was a predominant strain that was isolated more than once, and only one of these patients carried strains with a similarity index less than 80%. With the exception of two patients, each patient carried a major strain that became less susceptible to fluconazole. The similarity index for the unrelated strains was 59%. CONCLUSIONS: HIV-infected patients may carry a mixed population of strains, but the strains tend to be related to each other. The strains were maintained throughout the course of infection and at least one developed secondary resistance to fluconazole.

Correlation of in-vitro susceptibility test results with clinical response: a study of azole therapy in AIDS patients.

The in-vitro susceptibilities of 40 clinical isolates of Candida albicans to ketoconazole and fluconazole were determined and an attempt was made to correlate these data with the clinical responses of the patients from whom the strains were originally isolated to treatment with these agents. Of 40 patients with the acquired immunodeficiency syndrome (AIDS) with oropharyngeal and/or oesophageal candidosis, 21 received ketoconazole and 19 fluconazole. Susceptibility testing was performed by a microbroth dilution method with RPMI-2% glucose medium according to the recommendations of the National Committee for Clinical Laboratory Standards; growth inhibition was estimated spectrophotometrically and the MIC endpoint was defined in terms of the IC1/2. The MICs of 236 additional strains of C. albicans, which were also isolated from AIDS patients, were used to establish a susceptibility profile for this species. On the basis of the susceptibility test results and the clinical responses of the 40 patients, the following tentative breakpoints for ketoconazole and fluconazole are proposed: patients with infections caused by C. albicans strains with MICs of ketoconazole and fluconazole or < or = 0.001 and < or = 0.25 mg/L respectively would be expected to respond to treatment with these agents and isolates with MICs which meet these criteria are therefore classified as susceptible; patients with infections caused by strains with MICs of ketoconazole and fluconazole of > or = 0.06 and > or = 16.0 mg/L respectively would not be expected to respond to treatment with these agents and isolates with MICs which meet these criteria are therefore classified as resistant; the response of patients with infections caused by strains with MICs of ketoconazole and fluconazole of 0.003-0.03 and 0.5-8.0 mg/L respectively cannot be reliably predicted and isolates with MICs which fall within these ranges are therefore classified as being of indeterminate susceptibility. The present study demonstrates that the results of in-vitro susceptibility testing with RPMI-2% glucose broth correlate with the clinical response to therapy and can be used to facilitate optimal treatment in AIDS patients with oropharyngeal and/or oesophageal candidosis.

Treatment of encrusted cystitis caused by Corynebacterium group D2 with norfloxacin, ciprofloxacin, and teicoplanin in an experimental model in rats.

Oral doses of norfloxacin (80 mg/kg of body weight per day) and ciprofloxacin (25 and 80 mg/kg/day) and intramuscular doses of teicoplanin (5 mg/kg/day), all administered once a day for 10 days, were evaluated as a means of preventing encrusted cystitis caused by Corynebacterium group D2. Zinc disks dipped into a 24-h broth culture of these microorganisms were inserted into the bladders of female Wistar rats, and treatment was started 14 days after bacterial challenge. The appearance of encrusted cystitis was directly related to a documented urinary tract infection by these coryneforms (71.7 and 0% for rats with positive and negative urine cultures, respectively). All rats that died between days 18 to 43 after bacterial challenge presented very severe encrusted cystitis, which was prevented by teicoplanin and high doses of ciprofloxacin. Rats surviving up to day 44 after bacterial challenge were sacrificed; they presented a lower incidence of encrusted cystitis which was also less severe, with teicoplanin and a high dose of ciprofloxacin being more active in reducing the rate of positive cultures (78.8 and 65.7% reduction, respectively). All antibiotics and doses used were active in vivo at preventing encrusted cystitis by Corynebacterium group D2, but the best therapeutic effect was obtained with teicoplanin.