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In vitro selection of resistance to clarithromycin in Streptococcus pneumoniae clinical isolates.
- Source :
-
Journal of chemotherapy (Florence, Italy) [J Chemother] 2005 Apr; Vol. 17 (2), pp. 161-8. - Publication Year :
- 2005
-
Abstract
- In this study the effects of exposure to serum, lung and breakpoint concentrations on Streptococcus pneumoniae susceptibility to clarithromycin, azithromycin, amoxicillin/clavulanate, levofloxacin and moxifloxacin were evaluated. Development of resistance was determined by multi-step and single-step methodologies. In the first experimental set, minimum inhibitory concentrations (MICs) were determined after 10 passages on antibiotic-gradient plates and 10 passages on antibiotic-free plates. Acquisition of resistance was defined as an increase of > or = 4-fold from the starting MIC. In single-step studies, the rate of spontaneous mutations was calculated after a passage on antibiotic-containing agar plates. Azithromycin and levofloxacin gave the highest number of strains with MIC increased of at least 4 times the starting value, followed by moxifloxacin and by clarithromycin which only at the lowest concentration tested selected for resistance in 5 strains. Amoxicillin/clavulanate never displayed > or = 4-fold MIC increase. Frequencies of mutation were lower for clarithromycin and moxifloxacin than for the comparators. At lung concentrations clarithromycin had limited potential to select for resistance.
- Subjects :
- Amoxicillin pharmacology
Aza Compounds pharmacology
Azithromycin pharmacology
Fluoroquinolones
Humans
Levofloxacin
Microbial Sensitivity Tests
Moxifloxacin
Ofloxacin pharmacology
Quinolines pharmacology
Sampling Studies
Sensitivity and Specificity
Streptococcus pneumoniae isolation & purification
Clarithromycin pharmacology
Drug Resistance, Bacterial
Streptococcus pneumoniae drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 1120-009X
- Volume :
- 17
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Journal of chemotherapy (Florence, Italy)
- Publication Type :
- Academic Journal
- Accession number :
- 15920900
- Full Text :
- https://doi.org/10.1179/joc.2005.17.2.161