Active Ingredient: Azithromycin
We present here data obtained with a model of S. These cells were selected because they are quite permissive towards a variety of intracellular infectious agents, allowing detailed analysis of the effects of antibiotics without too much interference from the host-derived mechanisms of defense.
We selected commonly used drugs from three different classes of antibiotics on the basis of their contrasting behaviors concerning pharmacodynamics, cellular accumulation, and distribution properties. Thus, we chose i the aminoglycoside gentamicin, which is a drug characterized by a marked, intense concentration-dependent bactericidal activity 5 and a poor cellular accumulation but a preferential accumulation in lysosomes reviewed in reference 56; ii ciprofloxacin and moxifloxacin, which are examples of fluoroquinolones that, like aminoglycosides, show a marked concentration-dependent bactericidal effect 5 but accumulate quickly in cells and distribute in the cytosol 10; and iii azithromycin and telithromycin two macrolides, which are essentially bacteriostatic and time-dependent antibiotics 5, accumulate in cells to a large extent, and are largely localized in acidic vacuoles 9, 40.
All drugs were used throughout the present study at clinically pertinent concentrations to allow for chemotherapeutically meaningful comparisons.
Dose effects were correlated with cellular accumulation to delineate the intracellular pharmacodynamic properties of each drug in comparison with what was known or could be observed of their activities towards extracellular bacteria.
We used J 774 macrophages, a continuous reticulosarcoma cell line of murine origin, which were maintained exactly as previously described 53, 57. These cells are permissive towards a large number of intracellular bacteria.
Bacterial strain and susceptibility testing.
MICs were determined according to the recommendations of the U. National Committee for Clinical Laboratory Standards 1999. Time and dose-kill curve studies with broth.
Bacteria exhibiting logarithmic growth were resuspended at a density of 106 CFU per ml in Mueller-Hinton broth.
Setting up of a 24-h model of intracellular infection. Bacteria were then adjusted to a concentration of 3. This suspension was then used to replace the culture medium of macrophages to yield an initial bacterium-to-macrophage ratio of 0.
Macrophages were then washed twice with prewarmed phosphate-buffered saline PBS. Different protocols were then tested for the ability to support intracellular growth over a 24-h period without contamination of the extracellular medium as assessed by optic microscopy and by plating samples from culture medium on tryptic soy agar.
Bacteria were seen to contaminate the extracellular milieu after approximately 5 h, causing a marked acidification and subsequent cell death. In the latter cells. Take: 32 2 The information provide you availability and market price pneumonia for consumers to make infected choices.
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