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R A Fromtling

Publications and source records attributed to R A Fromtling.

At least 19 recordsLinked to original sources
PubMed2001

Human mycoses and advances in antifungal therapy.

The 11th Focus on Fungal Infections meeting was held in Washington, D.C., U.S.A., March 1416, 2001. At the conference, there were well-attended sessions that focused on the pathogenesis and therapy of fungal disease. This report focuses on new information on fungal incidence and pathogenesis as well as on the in vitro and clinical experience of established antifungal drugs (fluconazole, itraconazole, amphotericin B, liposomal formulations of amphotericin B, terbinafine) and the newer antifungal compounds approved for use (e.g., caspofungin) and in development (the new-generation azoles: voriconazole, posaconazole, ravuconazole, and the candins, micafungin and anidulafungin).

Journal Article↗
PubMed2000

Progress in antibacterial and antifungal chemotherapy.

The European Society of Clinical Microbiology and Infectious Diseases sponsored the 10th European Congress on Clinical Microbiology and Infectious Diseases in Stockholm, Sweden, May 28-31, 2000. At the ECMID, well-attended sessions were held which focused on the pathogenesis and therapy of viral, bacterial and fungal diseases. This report focuses on new information on resistance to antibacterial agents, including data from recent surveillance studies, and the in vitro and investigational clinical activity of new antibacterial (moxifloxacin, telithromycin) and antifungal (fluconazole, itraconazole, voriconazole, amphotericin B, liposomal formulations of amphotericin B, terbinafine and the candins) drugs.

Journal Article↗
PubMed1999

Yeasts and fluconazole susceptibility in the Philippines.

Identification and fluconazole susceptibility of 579 yeasts isolated from patients in 16 medical centers throughout the Philippines in 1997-98 is reported. Speciation revealed the following distribution of yeasts (with percent occurrence): Candida albicans (49.6%); C. parapsilosis (17.2%); C. tropicalis (14.9%); C. glabrata (6.2%); C. pelliculosa (4.3%); C. krusei (2.4%); C. guilliermondii (1.9%); Trichosporon cutaneum (1.7%); Cryptococcus neoformans (0.9%); Candida famata (0.5%); C. lusitaniae (0.2%) and Saccharomyces cerevisiae (0.2%). Using an agar disk diffusion assay for fluconazole susceptibility it was determined that 94% of the isolates were susceptible, 5% dose-dependent susceptible and only 1% resistant. All isolates of C. albicans were susceptible (one being dose dependent sensitive) to fluconazole. The only yeasts resistant to fluconazole were: C. guillermondii (1 isolate), C. glabrata (3 isolates) and C. parapsilosis (1 isolate).

Antifungal Agents↗
PubMed1998

Human mycoses and current antifungal therapy.

The Focus on Fungal Infections meeting has become a popular conference for specialists in medical mycology and antifungal chemotherapy. Highlights of the 8th meeting are reported, with a focus on infection and therapy. Although the incidence of mycoses has increased, the identification of these fungal etiologic agents remains difficult. Mucosal candidiasis caused by endogenous Candida albicans and Candida species remains the most common fungal manifestation in HIV-infected patients, while systemic infection by Aspergillus species also has increased in HIV patients. Two presenters at the meeting debated whether fungal infections in AIDS patients are becoming less common and less important. Various strategies for antifungal therapy in AIDS or HIV-positive patients were presented. Most fungal infections in solid organ transplant patients are due to Candida species or Aspergillus species; however, dematiaceous (dark-pigmented) fungi are becoming more common fungal pathogens in these patients. Antifungal therapy remains difficult in this patient group. The meeting included an overview of the current status of diagnosing fungal infections through serodiagnostic techniques. If properly validated, serology can be useful in fungal diagnosis since antigens and antibodies are easier to detect than the invading organism. Premature infants are at high risk for developing invasive fungal infections. Antifungal drugs have not been tested in controlled clinical trials in these patients, thus therapy is accomplished using adult treatment regimens and anecdotal experience. As regards the new lipid-based formulations of amphotericin B, published clinical studies are only now appearing in the literature and these reports suggest that the new formulations have reduced toxicity and comparable efficacy compared to conventional amphotericin B under various clinical conditions. Correlation of minimum inhibitory concentration (MIC) values with clinical response to therapy is beginning to emerge. Two fungal cell wall-active compounds have recently entered clinical trials: an echinocandin and the chitin-synthesis inhibitor nikkomycin Z. Pradimycin and analogues have been studied through experimental animal models with good success; however, phase I clinical trials suggested drug-related toxicities and development was stopped. New molecular targets also are being investigated in antifungal therapy.

Journal Article↗
PubMed1998

Medical mycology and current trends in antifungal chemotherapy.

The Medical Mycological Society of the Americas (MMSA) and the American Society for Microbiology (ASM) are both premier scientific organizations which held their annual conferences in Atlanta, Georgia, May 17-21, 1998. The MMSA scientific session focused on the role of animal models in drug development and on the immunology and molecular biology of the medically important fungi. The use of current molecular tools in identifying new fungal targets for the development of antifungal agents and for the study of fungal epidemiology was reviewed. At the ASM, several sessions were held which focused on the pathogenesis of fungal disease, the in vitro susceptibility testing of new (voriconazole, SCH-56592, LY-303366, metalloporphyrins) and established antifungal agents, the experimental in vivo activity of new antifungal drugs in various animal models of fungal disease and pediatric mycology; the clinical activity of fluconazole, itraconazole, liposomal nystatin and liposomal amphotericin B formulations was also reviewed.

Journal Article↗
PubMed1998

Advances in antifungal chemotherapy.

The American Society for Microbiology sponsored the 38th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), a premier annual scientific conference, in San Diego, California, September 24-27, 1998. At the ICAAC several sessions were held which focused on the pathogenesis of fungal disease, the in vitro susceptibility testing of new azole (voriconazole, Syn-2869, SCH-56592, carbendazim), echinocandin-like (FK-463, LY-303366, MK-0991), polyene (patricins) and established antifungal agents (fluconazole, itraconazole, amphotericin B, nystatin, terbinafine), the experimental in vivo activity of these new antifungal drugs in various animal models of fungal disease, and the clinical activity of fluconazole, itraconazole and liposomal amphotericin B formulations.

Journal Article↗
PubMed1993

Multicenter evaluation of a broth macrodilution antifungal susceptibility test for yeasts.

Thirteen laboratories collaborated to optimize interlaboratory agreement of results of a broth macrodilution procedure for testing three classes of antifungal drugs against pathogenic yeasts. The activities of amphotericin B, flucytosine, and ketoconazole were tested against 100 coded isolates of Candida albicans, Candida tropicalis, Candida parapsilosis, Candida lusitaniae, Torulopsis (Candida) glabrata, and Cryptococcus neoformans. Two starting yeast inoculum sizes (5 x 10(4) and 2.5 x 10(3) cells per ml) were compared, and readings were taken after 24 and 48 h of incubation. All other test conditions were standardized. The resultant turbidities in all tubes were estimated visually on a scale from 0 to 4+ turbidity, and MIC-0, MIC-1, and MIC-2 were defined as the lowest drug concentrations that reduced growth to 0, 1+, or 2+ turbidity, respectively. For flucytosine, agreement among laboratories varied between 57 and 87% for different inocula, times of incubation, and end point criteria. Agreement was maximized (85%) when the lower inoculum was incubated for 2 days and the MICs were defined as 1+ turbidity or less. For amphotericin B, variations in test conditions produced much smaller differences in interlaboratory agreement. For ketoconazole, interlaboratory agreement was poorer by all end point criteria. However, MIC-2 endpoints distinguished T. glabrata as resistant compared with the other species. Overall, the studies indicated that readings from the lower inoculum obtained on the second day of reading result in the greatest interlaboratory agreement. In combination with data from previous multicenter studies (National Committee for Clinical Laboratory Standards, Antifungal Susceptibility Testing: Committee Report, Vol. 5, No. 17, 1988; M. A. Pfaller, L. Burmeister, M. S. Bartlett, and M. G. Rinaldi, J. Clin. Microbiol. 26:1437-1441, 1988; M. A. Pfaller, M. G. Rinaldi, J. N. Galgiani, M. S. Bartlett, B.A. Body, A. Espinel-Ingroff, R.A. Fromtling, G.S. Hall, C.E. Hughes, F. C. Odds, and A. M. SUgar, J. Clin. Microbiol. 34:1648-1654, 1990), these findings will be used by the National Committee for Clinical Laboratory Standards to develop a standardized method for in vitro antifungal susceptibility testing for yeasts.

Antifungal Agents↗
PubMed1992

Collaborative comparison of broth macrodilution and microdilution antifungal susceptibility tests.

A collaborative comparison of macro- and microdilution antifungal susceptibility tests was performed in five laboratories. MICs of amphotericin B, fluconazole, flucytosine, and ketoconazole were determined in all five centers against 95 coded isolates of Candida spp., Cryptococcus neoformans, and Torulopsis glabrata. A standard protocol with the following National Committee for Clinical Laboratory Standards Subcommittee on Antifungal Susceptibility Testing recommendations was used: an inoculum standardized by spectrophotometer, buffered (RPMI 1640) medium (pH 7.0), incubation at 35 degrees C, and an additive drug dilution procedure. Two inoculum sizes were tested (1 x 10(4) to 5 x 10(3) to 2.5 x 10(3) CFU/ml) and three scoring criteria were evaluated for MIC endpoint determinations, which were scored as 0 (optically clear), < or = 1 (slightly hazy turbidity), and < or = 2 (prominent decrease in turbidity compared with that of the growth control). Overall intra- and interlaboratory reproducibility was optimal with the low-density inoculum, the second-day readings, and MICs scored as either 1 or 2. The microdilution MICs demonstrated interlaboratory agreement with most of the four drugs higher than or similar to that of the macrodilution MICs. In general, there was good interlaboratory agreement with amphotericin B, fluconazole, and flucytosine; ketoconazole gave more variable results.

Antifungal Agents↗
PubMed1992

Sphingofungins A, B, C, and D; a new family of antifungal agents. I. Fermentation, isolation, and biological activity.

In screening for antifungal inhibitors from fungi, four related antifungal agents have been isolated from the cultivation of Aspergillus fumigatus ATCC 20857. These agents were initially produced by the microorganism growing on a solid millet-based medium. A liquid medium containing both glucose and glycerol has also been developed in which these antibiotics are produced in two phases. These novel compounds, sphingofungins A, B, C, and D, show a limited spectrum of antifungal activity but were especially effective against Cryptococcus species.

Amino Acids↗
PubMed1991

(Acyloxy)alkyl carbamate prodrugs of norfloxacin.

As a new prodrug approach to norfloxacin (NFLX) we prepared the acetoxyalkyl carbamates of the type NFLX-CO-OCHR-OAc by the reaction of sodium or mercuric acetate on NFLX alpha-chloroalkyl carbamates. These produrgs did not have the bitter taste of NFLX. In vitro, the acetoxyethyl carbamate exhibited activity only against Staphylococcus spp. and was inactive against Gram-negative organisms. However, in the presence of serum and intestinal homogenate, esterase-catalyzed hydrolysis of the ester bond in these modified carbamates led to a cascade reaction resulting in the rapid regeneration of NFLX. At high oral doses of the prodrug, the acetaldehyde produced as a side product in the breakdown of the promoiety caused a slight decrease in alcohol metabolism in a mouse model. The bioavailability of NFLX from the acetoxyethyl carbamate was lower compared to an equivalent dose of NFLX when given as an oral suspension in rhesus monkeys, presumably because of the lower aqueous solubility of the prodrug.

Animals↗
PubMed1991

Restricticin, a novel glycine-containing antifungal agent.

Restricticin (1) is a naturally-occurring antifungal agent which contains triene, pyran and glycine ester functionalities and is unrelated to any previously known family of natural products. This unstable compound, as well as its corresponding N,N-dimethyl derivative (2), have been produced and isolated from both solid and liquid fermentations of Penicillium restrictum. The desglycyl hydrolysis product, restrictinol (3), was produced via the hydrolysis of pure restricticin and as an artifact of the isolation of restricticin.

Antifungal Agents↗
PubMed1990

Treatment of Pneumocystis carinii pneumonia with 1,3-beta-glucan synthesis inhibitors.

Pneumocystis carinii pneumonia is a major cause of death in AIDS patients in the United States. The presently available treatments have limited use due to a high incidence of adverse reactions. Therefore, there is an urgent need for a safer method for treatment and prevention of this disease. Recent evidence has suggested that P. carinii is related to fungi and that the wall of the cyst form contains 1,3-beta-glucan as a major constituent. Based on this, several proposed 1,3-beta-glucan synthesis inhibitors were evaluated for their ability to control P. carinii pneumonia in vivo. Compounds from two classes of 1,3-beta-glucan synthesis inhibitors, the echinocandins and papulacandins, were found to be effective against P. carinii.

Animals↗
PubMed1990

Collaborative investigation of variables in susceptibility testing of yeasts.

A multicenter study was performed to evaluate the effect of medium, incubation time (24 and 48 h), and temperature (30 and 35 degrees C) on intra- and interlaboratory variations in MICs of flucytosine, amphotericin B, and ketoconazole for yeasts. Testing was performed on coded isolates of Candida species (11 strains) and Cryptococcus neoformans (2 strains) by using a standard macrodilution protocol 11 laboratories. Four chemically defined media buffered to pH 7.0 with morpholinepropanesulfonic acid were evaluated, including buffered yeast nitrogen base, synthetic amino acid medium-fungal, RPMI 1640 medium, and high-resolution antifungal assay medium. Intralaboratory variability was less than or equal to fourfold for 97% of the replicate sets of data. The highest level of interlaboratory agreement, irrespective of antifungal agent or incubation conditions, was observed with RPMI 1640 medium. Intralaboratory variability was less than or equal to fourfold for 93% of the determinations with ketoconazole and 100% with flucytosine tested in RPMI 1640 medium at 35 degrees C for 24 h. Variability in amphotericin B results was less than or equal to fourfold for 81% of the determinations in RPMI 1640 medium at 35 degrees C for 48 h. The rank order of MICs within each antifungal test group was similar among the various laboratories and was generally in agreement with the reference rank order regardless of the test medium that we used.

Amphotericin B↗
PubMed1989

Virulence and antifungal susceptibility of environmental and clinical isolates of Cryptococcus neoformans from Puerto Rico.

Studies on the distribution, epidemiology and pathogenesis of Cryptococcus neoformans on the island of Puerto Rico are few. We have studied mouse virulence and in vitro antifungal susceptibility of 133 isolates of C. neoformans: 121 environmental and 12 clinical (9 from AIDS patients), that were isolated in Puerto Rico. In experimental CD-1 mice infected intravenously, the mean lethal dose 50% values (28 days) were greater than 5.2 x 10(6) and 1.1 x 10(5) cells/mouse for environmental and clinical isolates, respectively. Using an agar dilution assay, the minimum inhibitory concentrations of amphotericin B, ketoconazole and 5-fluorocytosine were comparable for environmental and clinical isolates in both yeast nitrogen dextrose base agar and Kimming's agar. These data suggest a difference in lethality for mice, but no difference in antifungal susceptibility of environmental and clinical isolates of C. neoformans obtained in Puerto Rico.

Animals↗
PubMed1989

Isolation of saprophytic Cryptococcus neoformans from Puerto Rico: distribution and variety.

Until the present decade, no studies had been conducted in Puerto Rico on the saprophytic distribution and variety of Cryptococcus neoformans. Samples (522) of pigeon droppings from 14 western towns were tested for the presence of C. neoformans. The yeast was recovered from 24.7% (129 isolates) of the samples, representing 10 of the 14 towns studied. All environmental isolates were identified as C. neoformans var. neoformans using canavanine-glycine-bromthymol blue (CGB) agar. The yeast was isolated from 79.4% of the samples in one town, Isabela. The average number of yeast cells isolated from sites within this municipality was 5.1 x 10(5) per gram of pigeon droppings. This was 2.6 times the average number of yeast cells of C. neoformans isolated from sites in other towns. In addition, the yeast was isolated from four patients with the acquired immune deficiency syndrome (AIDS), each of whom died of cryptococcal meningitis. Each of these poorly encapsulated isolates was identified as C. neoformans var. neoformans using CGB agar. The results of this investigation demonstrate that C. neoformans var. neoformans is prevalent in Puerto Rico.

Acquired Immunodeficiency Syndrome↗
PubMed1989

L-671,329, a new antifungal agent. III. In vitro activity, toxicity and efficacy in comparison to aculeacin.

L-671,329 is a novel, echinocandin-like natural product that possesses potent anti-Candida activity, including activity against Candida parapsilosis. The in vitro MICs of L-671,329 were comparable to aculeacin against 18 yeasts and three filamentous fungi in an agar dilution assay. L-671,329 lysed mouse red blood cells (RBCs) at a concentration of 400 micrograms/ml, but not at 50 or 12.5 micrograms/ml. Aculeacin lysed RBCs at 400 and 50 micrograms/ml. L-671,329 significantly prolonged survival of mice infected with Candida albicans (ED50 3.38 mg/kg) following twice-daily intraperitoneal dosing for five consecutive days. The prolongation observed was greater than that seen with aculeacin therapy (ED50 6.44 mg/kg). No acute or chronic toxicities of L-671,329 or aculeacin (as measured by mortality) were detected at a concentration of 100 mg/kg following intraperitoneal administration (TD50 greater than 100 mg/kg). Both L-671,329 and aculeacin eradicated cells of C. albicans from the kidneys of infected mice. L-671,329 eradicated the yeast at therapeutic concentrations of 12.5 to 100 mg/kg. Aculeacin eradicated yeast cells at therapy concentrations of 25 to 100 mg/kg. L-671,329 has potential as an anti-Candida compound.

Animals↗
PubMed1989

L-658,310, a new injectable cephalosporin. I. In vitro antibacterial properties.

The in vitro antibacterial spectrum of L-658,310, a new semisynthetic cephalosporin, was compared with ceftazidime, aztreonam and piperacillin against a wide variety of randomly selected human clinical isolates. The compound was found to be a broad spectrum bactericidal agent that was more potent than any of the comparison drugs against glucose nonfermenting bacteria. It has especially potent activity against Pseudomonas aeruginosa including multiply-resistant strains. The superior activity of L-658,310 against this group of organisms is attributed to the presence of the dihydroxy substituents on the 2-methylisoindoline moiety of the compound. L-658,310 is not cross-resistant with either imipenem, ceftazidime or piperacillin (representatives of three different classes of beta-lactam compounds) against P. aeruginosa. The lack of cross-resistance with ceftazidime extends to other glucose nonfermenters and several strains of Enterobacteriaceae as well. The compound is active against bacteria known to possess either R-plasmid- or chromosomally-mediated beta-lactamases.

Aerobiosis↗