Synergy time-kill studies against 40 methicillin-resistant Staphylococcus aureus (MRSA) strains of differing resistance phenotypes were conducted. Subinhibitory concentrations of telavancin were combined with sub-MIC concentrations of other antimicrobial agents that might be used in combination with telavancin to provide Gram-negative coverage. The highest incidence of synergy was found after 2...

The 3' end of rsbU, encoding the positive regulator of the stress factor sigma B, was identified as a hot spot for spontaneous IS256 insertion in Staphylococcus aureus SA137/93G. Interestingly, subinhibitory concentrations of chloramphenicol in combination with heat stress, as well as linezolid and spectinomycin at physiological temperatures, selected for such rsbU::IS256 insertion mutants. In ...

Background Recently, differences in development of bacterial resistance were observed for macrolides with short and long elimination half life. Although one might speculate that this observation is to be explained by prolonged subinhibitory concentrations at the site of bacterial dwelling, the pharmacokinetic (PK) confirmation of this theory is missing. Thus we set out to compare PK of azithrom...

In oxygen-aerated non-growing cells a subinhibitory ethanol concentration (1 G/L) causes an H /K exchange. An inhibitory ethanol concentration (30 G/L) slows down acidification but + + has no effect on its extent. The transmembrane pH depends directly on the ethanol level in the medium and is not lowered at high ethanol concentrations. Changes in membrane potential induced by ethanol are also c...

Bacteriocin AS-48 showed high bactericidal activity for mesophilic and psychrotrophic strains of Bacillus cereus over a broad pH range. AS-48 inhibition of the enterotoxin-producing strain LWL1 was enhanced by sodium nitrite, sodium lactate, and sodium chloride. The latter also enhanced AS-48 activity against strain CECT 131. Bacterial growth and enterotoxin production by strain LWL1 were compl...

Serial passage of Pseudomonas aeruginosa ATCC 27853 or Escherichia coli ATCC 25922 on agar with subinhibitory concentrations of norfloxacin rapidly produced isolates with minimal inhibitory concentrations (MICs) of norfloxacin up to 512-fold higher than that for the original strain. Although MICs of seven unrelated antibiotics were unchanged, increasing MICs occurred in parallel with norfloxaci...

An in vitro system was developed to test the phagocytic activity of human macrophages grown from blood monocytes in the presence of the antibiotics ampicillin, tetracycline, and chloramphenicol. (3)H-labeled Listeria monocytogenes served as test organism. Subinhibitory amounts of the antibiotics enhanced the phagocytic activity significantly (P < 0.025). Macrophages pretreated with the drugs in...