OBJECTIVES To measure the effect of opsonophagocytosis mediated by complement activated by specific antibodies on the co-amoxiclav serum bactericidal activity against Streptococcus pneumoniae strains with reduced susceptibility to beta-lactams (amoxicillin MICs of 2, 4, 8 and 16 mg/L). METHODS An open Phase I study measuring ex vivo bactericidal activity after anti-pneumococcal vaccination an...

In order to identify novel high value antibacterial targets it is desirable to delineate whether the inactivation of the target enzyme will lead to bacterial death or stasis. This knowledge is particularly important in slow growing organisms, like mycobacteria, where most of the viable anti-tubercular agents are bactericidal. A bactericidal target can be identified through the conditional delet...

The ink of sea hares (Aplysia californica) contains escapin, an L-amino acid oxidase that metabolizes L-lysine, thereby producing a mixture that kills microbes and deters attacking predators. This secretion contains H2O2,ammonia, and an equilibrium mixture of "escapin intermediate product" (EIP-K) that includes alpha-keto-epsilon-aminocaproic acid and several other molecules. Components of the ...

was prevented completely by DW-224a at concentrations of 1·, 2· and 4· MIC by 24 h, although regrowth occurred in the presence of ciprofloxacin at 1· MIC concentration. DW-224a also showed a dose-dependent bactericidal activity against all test organisms up to 4· the MIC. The MBCs of DW-224a in Mueller–Hinton broth (MHB) were identical to 1·MIC or at most twice the MIC for all strains tested. B...

OBJECTIVES Staphylococcus aureus small colony variants (SCVs) are slow-growing morphological variants associated with persistent infections. While vancomycin activity has been shown to be attenuated against SCVs of S. aureus, few data exist regarding daptomycin. The objective was to evaluate the pharmacodynamics of daptomycin against defined S. aureus mutants displaying the SCV phenotype. MET...

Helicobacter pylori (Hp) infection affects one-half of the human population and produces a variety of diseases from peptic ulcer to cancer. Current eradication therapies achieve modest success rates (around 70%), resistance to the antibiotics of choice is on the rise, and vaccination has not proved to be successful yet. Using an essential Hp protein, flavodoxin, as target, we identified three l...

Lactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide into hypothiocyanite, a reaction which can protect bacterial and mammalian cells from killing by hydrogen peroxide. The present study demonstrates, however, that lactoperoxidase in the presence of thiocyanate can actually potentiate the bactericidal and cytotoxic effects of hydrogen peroxide under specific conditions, s...

An oral infectious disease, dental caries, is caused by the cariogenic streptococci Streptococcus mutans. The expected preventive efficiency for prophylactics against dental caries is not yet completely observed. Nisin, a bacteriocin, has been demonstrated to be microbicidal against S. mutans, and liposome-encapsulated nisin improves preventive features that may be exploited for human oral heal...

A systematic analysis of the bacteriostatic/bactericidal effect of several antibiotics used in veterinary medicine was carried out by time-kill kinetic analysis using P. haemolytica, P. multocida, A. pleuropneumoniae, and E. coli. The antibiotics tested were enrofloxacin, danofloxacin, erythromycin, tilmicosin, penicillin G, ceftiofur and tetracycline. Unexpectedly, the antibiotics well charact...

The influence of interferon (IFN)–g and interleukin (IL)–6 on the intracellular growth of Listeria monocytogenes phagocytosed from the apical pole was examined in polarized Caco2 cells. IFN-g (from the apical pole) and IL-6 (from the basolateral pole) considerably reduced the bacterial intracellular growth, an effect largely abolished by l-monomethyl arginine. Both cytokines caused overexpressi...