linezolid and Peritonitis

Natural bisindole alkaloids such as Hyrtinadine A and Alocasin A, which are known to exhibit diverse bioactivities, provide promising chemical scaffolds for drug development. By optimizing the Masuda borylation-Suzuki coupling sequence, a library of various natural product-derived and non-natural (di)azine-bridged bisindoles was created. While unsubstituted bisindoles were devoid of antibacterial activity, 5,5'-chloro derivatives were highly active against methicillin-resistant

Topics: Alkaloids; Animals; Anti-Bacterial Agents; Cell Line; Cell Survival; Female; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Indoles; Methicillin-Resistant Staphylococcus aureus; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Peritonitis; Pyruvate Kinase; Rabbits

Bacterial fatty acid synthases are promising antibacterial targets against multidrug-resistant pathogens. Platensimycin (PTM) is a potent FabB/FabF inhibitor, while its poor pharmacokinetics hampers the clinical development. In this study, a focused library of PTM derivatives was prepared through thiolysis of PTM oxirane (

Topics: Adamantane; Aminobenzoates; Anilides; Animals; Anti-Bacterial Agents; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Mice; Mice, Inbred C57BL; Models, Molecular; Peritonitis; Small Molecule Libraries; Staphylococcal Infections; Staphylococcus

Platensimycin (PTM), originally isolated from soil bacteria Streptomyces platensis, is a potent FabF inhibitor against many Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci. However, the further clinical development of PTM is hampered by its poor pharmacokinetic properties. In this study, 20 PTM derivatives were prepared by Suzuki-Miyaura cross-coupling reactions catalyzed by Pd (0)/C. Compared to PTM, 6-pyrenyl PTM (6t) showed improved antibacterial activity against MRSA in a mouse peritonitis model. Our results support the strategy to target the essential fatty acid synthases in major pathogens, in order to discover and develop new generations of antibiotics.

Topics: Adamantane; Aminobenzoates; Anilides; Animals; Anti-Bacterial Agents; Disease Models, Animal; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Molecular Docking Simulation; Peritonitis; Staphylococcal Infections

We recently reported on the discovery of a novel antibacterial (2) with a 4(3H)-quinazolinone core. This discovery was made by in silico screening of 1.2 million compounds for binding to a penicillin-binding protein and the subsequent demonstration of antibacterial activity against Staphylococcus aureus. The first structure-activity relationship for this antibacterial scaffold is explored in this report with evaluation of 77 variants of the structural class. Eleven promising compounds were further evaluated for in vitro toxicity, pharmacokinetics, and efficacy in a mouse peritonitis model of infection, which led to the discovery of compound 27. This new quinazolinone has potent activity against methicillin-resistant (MRSA) strains, low clearance, oral bioavailability and shows efficacy in a mouse neutropenic thigh infection model.

Topics: Animals; Anti-Bacterial Agents; Cell Proliferation; Disease Models, Animal; Dose-Response Relationship, Drug; Gram-Positive Bacteria; Hep G2 Cells; Humans; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Molecular Structure; Peritonitis; Quinazolinones; Structure-Activity Relationship

The rising rates of antibiotic resistance accentuate the critical need for new antibiotics. Daptomycin is a new antibiotic with a unique mode of action and a rapid in vitro bactericidal effect against gram-positive organisms. This study examined the kinetics of daptomycin's bactericidal action against peritonitis caused by methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in healthy and neutropenic mice and compared this activity with those of other commonly used antibiotics. CD-1 mice were inoculated intraperitoneally with lethal doses of MSSA (Xen-29) or MRSA (Xen-1), laboratory strains transformed with a plasmid containing the lux operon, which confers bioluminescence. One hour later, the animals were given a single dose of daptomycin at 50 mg/kg of body weight subcutaneously (s.c.), nafcillin at 100 mg/kg s.c., vancomycin at 100 mg/kg s.c., linezolid at 100 mg/kg via gavage (orally), or saline (10 ml/kg s.c.). The mice were anesthetized hourly, and photon emissions from living bioluminescent bacteria were imaged and quantified. The luminescence in saline-treated control mice either increased (neutropenic mice) or remained relatively unchanged (healthy mice). In contrast, by 2 to 3 h postdosing, daptomycin effected a 90% reduction of luminescence of MSSA or MRSA in both healthy and neutropenic mice. The activity of daptomycin against both MSSA and MRSA strains was superior to those of nafcillin, vancomycin, and linezolid. Against MSSA peritonitis, daptomycin showed greater and more rapid bactericidal activity than nafcillin or linezolid. Against MRSA peritonitis, daptomycin showed greater and more rapid bactericidal activity than vancomycin or linezolid. The rapid decrease in the luminescent signal in the daptomycin-treated neutropenic mice underscores the potency of this antibiotic against S. aureus in the immune-suppressed host.

Topics: Acetamides; Animals; Anti-Bacterial Agents; Colony Count, Microbial; Daptomycin; Female; Linezolid; Luminescent Measurements; Methicillin Resistance; Mice; Microbial Sensitivity Tests; Neutropenia; Oxazolidinones; Peritonitis; Staphylococcus aureus

DNA binding ligands with potent antimicrobial activity against Gram-positive bacteria were further optimized by variation of the internal aromatic amino acids. This modification led to compounds with improved in vivo efficacy in lethal murine models of peritonitis (methicillin-resistant S. aureus, MRSA) and lung infection (S. pneumoniae).

Topics: Amino Acids, Aromatic; Animals; Anti-Bacterial Agents; Disease Models, Animal; DNA; Ligands; Lung Diseases; Mice; Peritonitis; Staphylococcal Infections; Staphylococcus aureus; Streptococcal Infections; Streptococcus pneumoniae