MICs are commonly used to assess the in vitro activities of antimicrobial agents; however, they provide minimal information on the pattern of bacterial activities. Time-kill studies with extensive sampling allow assessment of both the rate and extent of bacterial killing and regrowth. We compared imipenem and meropenem by both MIC-MBC testing and a time-kill study with P. aeruginosa 27853. In t...

We evaluated the bactericidal activity of RP 59500 (quinupristin-dalfopristin) against fibrin-platelet clots (FPC) infected with two clinical isolates of Staphylococcus aureus, one constitutively erythromycin and methicillin resistant (S. aureus AW7) and one erythromycin and methicillin susceptible (S. aureus 1199), in an in vitro pharmacodynamic infection model. RP 59500 was administered by co...

This study aims to evaluate, in vitro, antibacterial activity of four novel sulfonamide derivatives (1a-d) against Staphylococcus aureus: reference strain ATCC 25923 and 40 clinical isolates. Inhibition zones were performed with the disk diffusion method. The MIC values were determined by the dilution broth method. A 48 hours MIC-Kinetic curve was performed for the tested compounds. All compoun...

Although many parameters have been described to quantitate the killing and regrowth of bacteria, substantial shortcomings are inherent in most of them, such as low sensitivity to pharmacokinetic determinants of the antimicrobial effect, an inability to predict a total effect, insufficient robustness, and uncertain interrelations between the parameters that prevent an ultimate determination of t...

Gram-negative bacteria can alter the composition of the lipopolysaccharide (LPS) layer of the outer membrane as a response to different growth conditions and external stimuli. These alterations can, for example, promote attachment to surfaces and biofilm formation. The changes occur in the outermost layer of the cell and may consequently influence interactions between bacterial cells and surrou...

Lactobacillus casei grows in the absence of vitamin Ba, provided that D-alanine and an unidentified peptide are added to a medium complete in other nutrients (1, 2). A partial hydrolysate of protein contained several chromatographically distinct fractions that possessed this “peptide factor” activity (3). It appeared likely that a single amino acid linked in a variety of combinations was respon...