Garenoxacin is effective against bacteria invading cells such as Streptococcus pyogenes and Haemophilus influenzae

Abstract

Background: Recurrent tonsillitis is one of the most common otolaryngological disorders caused by bacteria invading cells such as Streptococcus pyogenes (S. pyogenes) and Haemophilus influenzae. The aim of this study was to investigate the effect of antibacterial drugs against bacteria that have invaded cells.Results: The intracellular invasion of Detroit 562 cells by five strains of nontypeable Haemophilus influenzae (NTHi) and four strains of Streptococcus pyogenes was investigated. The antibacterial drugs used were garenoxacin (GRNX), clarithromycin (CAM), amoxicillin (AMPC), cefditoren pivoxil (CDTR-PI), and levofloxacin (LVFX). Both NTHi and S. pyogenes fully invaded Detroit 562 cells in 6 h. Both NTHi and S. pyogenes had reduced susceptibility to CAM. GRNX, CAM, and LVFX were effective against bacteria invading the cells, but AMPC and CDTR-PI were not effective. GRNX was the most effective.Conclusion: GRNX was the most effective agent against bacteria invading cells.