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[Intracellular penetration of 5 quinolones into non-phagocytic cells]
I García1, A Pascual, M C Conejo
1Departmento de Microbiología, Facultad de Medicina, Universidad de Sevilla.
Background:
The intracellular penetration and activity of antimicrobial agents can be an important factor in the treatment of infections caused by intracellular pathogens. The new quinolones are able to penetrate into phagocytes, but only a few studies have evaluated other types of cells. The purpose of this study is to evaluate the intracellular penetration of ofloxacin, levofloxacin, lomefloxacin, sparfloxacin and BAY Y 3118 into human polymorphonuclear leukocytes and tissue cultured epithelial cells.
Methods:
Intracellular penetration was evaluated by a fluorometric assay for all the quinolones evaluated except for sparfloxacin, which was evaluated by a radiometric assay.
Results:
All the quinolones evaluated reached intracellular concentrations higher than extracellular ones. The penetration of sparfloxacin and BAY Y 3118 into the epithelial cells was similar to those observed for PMNs (cellular to extracellular concentration ratio; C/E > or = 4). The C/E values of ofloxacin, levofloxacin and lomefloxacin for epithelial cells were lower than those observed in PMN, but still yielding C/E values > or = 2.
Insights
New quinolone antibiotics effectively penetrate human cells, reaching higher intracellular than extracellular concentrations. This cellular uptake is crucial for treating infections caused by intracellular pathogens.
Area of Science:
- Pharmacology
- Microbiology
- Cell Biology
Context:
- Intracellular pathogens pose treatment challenges due to limited antimicrobial penetration.
- Quinolones are known to enter phagocytes, but their entry into other cell types requires further investigation.
Purpose:
- To assess the intracellular penetration of five quinolones: ofloxacin, levofloxacin, lomefloxacin, sparfloxacin, and BAY Y 3118.
- To compare quinolone penetration into human polymorphonuclear leukocytes (PMNs) and epithelial cells.
Summary:
- All evaluated quinolones achieved higher intracellular than extracellular concentrations.
- Sparfloxacin and BAY Y 3118 showed significant penetration into epithelial cells, comparable to PMNs (C/E ratio ≥ 4).
- Ofloxacin, levofloxacin, and lomefloxacin demonstrated lower epithelial cell penetration than PMNs, but still maintained C/E ratios ≥ 2.
Impact:
- Provides crucial data on the cellular uptake of key quinolone antibiotics.
- Informs the selection of appropriate antibiotics for treating intracellular bacterial infections.
- Highlights differential cellular penetration among quinolone agents, aiding therapeutic strategy development.