Bactericidal activity of levofloxacin against Streptococcus pneumoniae in an in-vitro model simulating serum pharmacokinetic parameters
Abstract
The objective of the current study was to evaluate the bactericidal activity of levofloxacin against Streptococcus pneumoniae at concentrations equivalent to those present in serum after a po dosage of 500 mg. Nine S. pneumoniae strains (one penicillin G-resistant, one penicillin G-intermediate resistant, and two penicillin G- and cefotaxime-resistant) were exposed to a levofloxacin concentration of 6 mg/L diluted at a terminal half-life (t1/2) of 8 h. Surviving S. pneumoniae (cfu/mL) were quantified up to 24 h by the membrane filtration method. Levofloxacin was rapidly bactericidal and reduced the quantity of inoculum to below the detection level of 10 cfu/mL within 2.5-5.15 h, irrespective of susceptibility to penicillin G or cefotaxime. No viable S. pneumoniae could be detected at the end of the observation period (24 h). All strains except one (strain 17134) had an MIC < 1.0 mg/L, and the minimum bactericidal concentrations (MBCs) were, at the most, one dilution higher than the respective MICs. The inoculum was high, ranging from 2.9 x 10(5) to 7.5 x 10(6) cfu/mL. The time required to achieve 99% death ranged from 0.9 to 3.1 h, and was longest for strain 17134 which had an MIC of 1.0 mg/L and an MBC of 2.0 mg/L. A 99.9% reduction in inoculum was achieved within 1.5-4.15 h. At a serum concentration achievable after a single po dosage of 500 mg, levofloxacin showed rapid and complete bactericidal activity against the S. pneumoniae strains tested.
Read the paper
Related studies
- Severe clinical outcomes of COVID-19 associated with proton pump inhibitors: a nationwide cohort study with propensity score matching
- Levofloxacin-Induced Tendon Rupture: A Case Report and Review of the Literature
- Association between cord blood 25-hydroxyvitamin D concentrations and respiratory tract infections in the first 6 months of age in a Korean population: a birth cohort study (COCOA)
- Neuroprotective Effects of Epicatechin against Oxidative Stress-Induced Cognitive Impairment: A Systematic Review and Meta-Analysis
- Quality evaluation and in vitro interaction studies between levofloxacin 250mg and diclofenac sodium 50mg tablets
- Molecular Epidemiology of mcr-1 -Positive Polymyxin B-Resistant Escherichia coli Producing Extended-Spectrum β-Lactamase (ESBL) in a Tertiary Hospital in Shandong, China
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.