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Effect of azithromycin, roxithromycin and erythromycin on human polymorphonuclear leukocyte function against
A Pascual1, G López-López, J Aragón
1Department of Microbiology, School of Medicine, Seville, Spain.
Abstract:
The effect of three macrolides (azithromycin, roxithromycin and erythromycin) on the interaction in vitro of human polymorphonuclear leukocytes (PMNs) with Staphylococcus aureus was examined. The exposure of S. aureus to 0.25 MIC of roxithromycin and erythromycin but not of azithromycin significantly increased the uptake of opsonized bacteria by human PMNs. The preincubation of PMNs with 1, 10 and 25 mg/l of the three antimicrobial agents did not affect either the uptake of S. aureus or the superoxide radical production by human PMNs. At these same concentrations the three agents showed slight but not significant intracellular activity in PMNs against S. aureus. It is concluded that treatment of S. aureus with subinhibitory concentrations of roxithromycin and erythromycin enhanced phagocytosis by PMNs, but the three macrolides tested did not directly affect the functions of human PMNs against S. aureus.
Insights
Subinhibitory concentrations of roxithromycin and erythromycin enhance Staphylococcus aureus phagocytosis by human polymorphonuclear leukocytes (PMNs). Azithromycin did not show this effect, and macrolides did not directly impact PMN functions.
Area of Science:
- Immunology
- Microbiology
- Pharmacology
Background:
- Staphylococcus aureus is a common pathogen.
- Polymorphonuclear leukocytes (PMNs) are key immune cells in combating bacterial infections.
- Macrolide antibiotics are widely used to treat bacterial infections.
Purpose of the Study:
- To investigate the in vitro effects of azithromycin, roxithromycin, and erythromycin on the interaction between human PMNs and Staphylococcus aureus.
- To determine if subinhibitory concentrations of macrolides alter bacterial susceptibility to phagocytosis.
- To assess the direct impact of macrolides on PMN functions like bacterial uptake and superoxide production.
Main Methods:
- Exposure of Staphylococcus aureus to subinhibitory concentrations (0.25 MIC) of azithromycin, roxithromycin, and erythromycin.
- Incubation of human PMNs with S. aureus in the presence or absence of macrolide-treated bacteria.
- Measurement of bacterial uptake by PMNs.
- Assessment of PMN superoxide radical production.
- Evaluation of intracellular activity of macrolides against S. aureus within PMNs.
Main Results:
- Exposure of S. aureus to subinhibitory concentrations of roxithromycin and erythromycin significantly increased the uptake of opsonized bacteria by human PMNs.
- Azithromycin did not enhance bacterial uptake by PMNs under the tested conditions.
- Preincubation of PMNs with macrolides at concentrations of 1, 10, and 25 mg/l did not affect bacterial uptake or superoxide radical production.
- Macrolides exhibited slight, non-significant intracellular activity against S. aureus within PMNs.
Conclusions:
- Subinhibitory concentrations of roxithromycin and erythromycin enhance the phagocytosis of Staphylococcus aureus by human PMNs.
- Azithromycin does not appear to enhance S. aureus phagocytosis at subinhibitory concentrations.
- The tested macrolides do not directly impair human PMN functions related to S. aureus clearance.