Conserved fungal genes as potential targets for broad-spectrum antifungal drug discovery.

The discovery of novel classes of antifungal drugs depends to a certain extent on the identification of new, unexplored targets that are essential for growth of fungal pathogens. Likewise, the broad-spectrum capacity of future antifungals requires the target gene(s) to be conserved among key fungal pathogens. Using a genome comparison (or concordance) tool, we identified 240 conserved genes as candidates for potential antifungal targets in 10 fungal genomes.

39th Interscience Conference on Antimicrobial Agents and Chemotherapy of the American Society for Microbiology.

The 39th ASM ICAAC Meeting, attended by over 16,000 delegates, highlighted numerous late-stage development antibacterials. The presentation of over 600 reports (posters, symposia and oral presentations) regarding resistance emergence underscores the evolving landscape of antibiotic susceptibility worldwide. Although bacterial genomic efforts are slowly expanding the potential sources of novel targets, the established antibacterial classes, including quinolones, beta-lactams, protein synthesis inhibitors and carbapenems, were most prevalent among the presentations.

98th General Meeting of the American Society for Microbiology. May 17-21, 1998; Atlanta, GA.

The 98th General Meeting of the American Society for Microbiology was held from May 17-21, 1998, in Atlanta, Georgia and was attended by well over 10,000 scientists. The theme of antibiotic resistance dominated the meeting with numerous presentations on resistance mechanisms, new targets and potential antimicrobial agents. Many new insights into the understanding of microbial physiology were provided.

Importance of antifungal drug-resistance: clinical significance and need for novel therapy.

The incidence of fungal infections has increased dramatically over the past few decades due to the increase in the members of the population susceptible to such infections. This population includes individuals undergoing chemotherapy for cancer, those enduring long-term treatment with antibacterial agents, those receiving immunosuppressive drugs following transplantations, or those immunosuppressed due to diseases, such as AIDS, or malignancies. Newer antifungal agents, namely the triazoles, have aided in both the treatment of fungal infections and in the prevention of disease in susceptible individuals.

Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).

Over 10,000 research scientists attended the ICAAC meeting in Toronto, Canada. The continued increase in the rate of resistance in bacteria and fungi and the underlying mechanisms of resistance were the focus of many presentations this year. So, too, were the attempts to combat this emerging resistance crisis.

Biaryl isoxazolinone antibacterial agents.

In an era of increasing resistance to classical antibacterial agents, the synthetic oxazolidinone series of antibiotics has attracted much interest. Zyvoxtrade mark was the first oxazolidinone to be approved for clinical use against infections caused by multi-drug resistant Gram-positive bacteria. In the course of studies directed toward the discovery of novel antibacterial agents, a new series of synthetic phenyl-isoxazolinone agents that displayed potent activity against Gram-positive bacterial strains was recently discovered at Bristol-Myers Squibb.

Discovery of isoxazolinone antibacterial agents. Nitrogen as a replacement for the stereogenic center found in oxazolidinone antibacterials.

A series of potential antimicrobial derivatives possessing bioisosteric replacements for the central oxazolidinone ring found in oxazolidinone antibacterials have been prepared. The design concept involved replacement of the requisite sp(3)-hybridized stereogenic center found at the 5-position of the oxazolidinone with a nitrogen atom. The synthesis and antibacterial activity of three such ring systems, the benzisoxazolinones, pyrroles, and isoxazolinones is described.

Comparison of the bactericidal activities and post-antibiotic effects of the Des-F(6)-quinolone BMS-284756, levofloxacin, and ciprofloxacin against methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

The bactericidal activities and post-antibiotic effects of BMS-284756 (T-3811ME), levofloxacin, and ciprofloxacin were evaluated against a methicillin-susceptible and a methicillin-resistant Staphylococcus aureus strain. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations, post-antibiotic effects, and post-antibiotic sub-MIC effects were determined and time-kill studies were performed for BMS-284756, levofloxacin, and ciprofloxacin. At 4-times and 10-times the MIC, time-kill kinetics over 3 h and over 24 h were similar for all three quinolones when effects were considered as multiples of the MIC.

Bactericidal activities of BMS-284756, a novel Des-F(6)-quinolone, against Staphylococcus aureus strains with topoisomerase mutations.

The antistaphylococcal activities of BMS-284756 (T-3811ME), levofloxacin, moxifloxacin, and ciprofloxacin were compared against wild-type and grlA and grlA/gyrA mutant strains of Staphylococcus aureus. BMS-284756 was the most active quinolone tested, with MICs and minimal bactericidal concentrations against S. aureus wild-type strain MT5, grlA mutant MT5224c4, and grlA/gyrA mutant EN8 of 0.

Comparison of efficacies of oral levofloxacin and oral ciprofloxacin in a rabbit model of a staphylococcal abscess.

Oral levofloxacin was compared to oral ciprofloxacin in a Staphylococcus aureus subcutaneous abscess model in rabbits. Rabbits were surgically prepared with subcutaneous wiffle balls (43 mm in diameter) and allowed to recover for 4 to 6 weeks. Rabbits were infected by direct injection into the capsule with S.

Antibacterial agents that inhibit two-component signal transduction systems.

A class of antibacterials has been discovered that inhibits the growth of Gram-positive pathogenic bacteria. RWJ-49815, a representative of a family of hydrophobic tyramines, in addition to being a potent bactericidal Gram-positive antibacterial, inhibits the autophosphorylation of kinase A of the KinA::Spo0F two-component signal transduction system in vitro. Analogs of RWJ-49815 vary greatly in their ability to inhibit growth of bacteria and this ability correlates directly with their activity as kinase A inhibitors.

The 97th Annual Meeting of the American Society for Microbiology.

The Annual Meeting of the American Society for Microbiology took place in Miami Beach, Florida, from May 4-8, 1997. Over 9000 scientists attended this meeting, which covers all major aspects of prokaryotic research (basic, applied, medical, and diagnostic). Genomics discussions were a major part of the meeting agenda, with scientists detailing both basic and applied research effort using genomics and bioinformatics.

Comparison of the postantibiotic and postantibiotic sub-MIC effects of levofloxacin and ciprofloxacin on Staphylococcus aureus and Streptococcus pneumoniae.

The postantibiotic subminimum inhibitory concentration effect (PA SME) may simulate in vivo drug exposure more accurately than the postantibiotic effect (PAE) since subinhibitory concentrations of drug persist between antibiotic dosings. In this study, we compared the PAEs and PA SMEs of levofloxacin and ciprofloxacin for clinical isolates of fluoroquinolone-susceptible Staphylococcus aureus and Streptococcus pneumoniae. At two times the MIC, PAEs of levofloxacin were an average of 0.

Assessment of the synergistic interactions of levofloxacin and ampicillin against Enterococcus faecium by the checkerboard agar dilution and time-kill methods.

Multidrug-resistant enterococci have become increasingly difficult to eradicate in a growing number of nosocomial infections. With the emergence of vancomycin-resistant enterococci, the use of synergistic antibiotic combinations has become one of the only remaining therapeutic options. Levofloxacin, the active l-isomer of ofloxacin, is a new oral and intravenous fluoroquinolone with a broad spectrum of activity against numerous Gram-positive, Gram-negative, and atypical organisms.

In vivo oral efficacy of levofloxacin for treatment of systemic Pseudomonas aeruginosa infections in a murine model of septicemia.

The in vivo efficacies of levofloxacin and ciprofloxacin in lethal, systemic Pseudomonas aeruginosa infections in mice were compared. MICs of levofloxacin and ciprofloxacin ranged from 0.5 to 2.

In vivo efficacies of levofloxacin and ciprofloxacin in acute murine hematogenous pyelonephritis induced by methicillin-susceptible and-resistant Staphylococcus aureus strains.

Levofloxacin, the active L-isomer of ofloxacin, has demonstrated strong activity against Staphylococcus aureus both in vitro and in vivo. In a murine model of hematogenous pyelonephritis, the in vivo efficacies of levofloxacin and ciprofloxacin were evaluated against two methicillin-susceptible and two methicillin-resistant S. aureus strains.

The effect of elastase-specific monoclonal and polyclonal antibodies on the virulence of Aspergillus fumigatus in immunocompromised mice.

Elastase has been implicated as a potential virulence factor involved in the invasion process of the opportunistic pathogen, Aspergillus fumigatus. Monoclonal and polyclonal antibodies, known to inhibit elastase in vitro, were employed in an immunocompromised mouse model of invasive aspergillosis to determine if the antibodies could protect mice from fatal infection. Individual monoclonal antibodies, known to inhibit elastase partially (13 to 23%), or combinations of monoclonal antibodies, known to inhibit elastase 70 to 100%, were tested in the mouse model.

Production and characterization of monoclonal antibodies to the carboxyl-terminal heptapeptide of endothelin-1.

Two cell lines, RR5.ET-1 and RR1.ET-1, that produce monoclonal antibodies specific for the carboxyl-terminal heptapeptide of endothelin-1 (ET-1) have been cloned and stabilized.

Inhibition of Aspergillus fumigatus elastase with monoclonal antibodies produced by using denatured elastase as an immunogen.

In preparing monoclonal antibodies to the elastase from Aspergillus fumigatus, we found that the enzyme was weakly immunogenic in BALB/c mice. Antiserum titers were only 1:1,000 to 1:5,000, and hybridomas secreted nonspecific immunoglobulin M (IgM). Denaturing the elastase in 0.

Purification and properties of the elastase from Aspergillus fumigatus.

Elastase, a potential virulence factor from the opportunistic pathogen Aspergillus fumigatus, was purified 220-fold from culture broth by fast-performance liquid chromatography employing anion exchange (Q Sepharose fast flow), cation exchange (S Sepharose fast flow), and gel filtration (Superose 12). Purified to near homogeneity, the elastase had an apparent molecular mass of 32 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (silver stain) but a mass of about 19.1 kDa as determined by gel filtration on Superdex 75.