Related Experiment Video
Updated: Aug 9, 2026
A High-throughput Compatible Assay to Evaluate Drug Efficacy against Macrophage Passaged Mycobacterium tuberculosis
Published on: March 24, 2017
Comparative in vitro activity of moxifloxacin by E-test against Streptococcus pyogenes
C F Amábile-Cuevas1, C Hermida-Escobedo, R Vivar
1Fundación LUSARA, Mexico City, Mexico. carlos.amabile@lusara.org
Abstract:
Macrolides are currently used to treat Streptococcus pyogenes infections where allergy or resistance prevents the use of penicillin. However, growing macrolide resistance is now seen worldwide, with rates of 5%-40% being reported. In this context it is therefore important to have other therapeutic options. The aim of this study was to ascertain the potential role of moxifloxacin, a third-generation fluoroquinolone, in the treatment of infections caused by group A S. pyogenes. The antimicrobial susceptibilities of S. pyogenes isolated from 197 adult patients with pharyngotonsillitis were analyzed by the E-test. Twelve percent of the isolates were resistant to macrolides, and 5% showed diminished susceptibility toward penicillin; none of the strains were resistant to cefotaxime or to moxifloxacin (90% minimum inhibitory concentration, 0.25 microg/mL). Therefore, moxifloxacin may be a therapeutic option in the management of S. pyogenes infections when penicillin cannot be used or when macrolide resistance may be a local issue. Clinical studies of moxifloxacin in pharyngotonsillitis are warranted.
Insights
Macrolide resistance is increasing in Streptococcus pyogenes infections. Moxifloxacin shows no resistance and may be a viable alternative when penicillin or macrolides are not suitable options.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Penicillin is the primary treatment for Streptococcus pyogenes infections.
- Macrolides are used for penicillin-allergic or resistant cases.
- Increasing macrolide resistance (5%-40%) necessitates alternative therapies.
Purpose of the Study:
- To evaluate moxifloxacin as a potential treatment for Streptococcus pyogenes infections.
- To assess the susceptibility of S. pyogenes to moxifloxacin.
Main Methods:
- Antimicrobial susceptibility testing of S. pyogenes isolates using E-test.
- Analysis of 197 isolates from adult patients with pharyngotonsillitis.
Main Results:
- 12% of isolates were macrolide-resistant; 5% showed reduced penicillin susceptibility.
- No S. pyogenes strains exhibited resistance to cefotaxime or moxifloxacin.
- The 90% minimum inhibitory concentration for moxifloxacin was 0.25 microg/mL.
Conclusions:
- Moxifloxacin demonstrates potent activity against S. pyogenes, including macrolide-resistant strains.
- Moxifloxacin is a potential therapeutic option for S. pyogenes infections when other antibiotics fail.
- Further clinical studies are recommended to confirm moxifloxacin efficacy in pharyngotonsillitis.
