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Effectiveness of antibacterial agents against cell-invading bacteria such as Streptococcus pyogenes and Haemophilus

Hiroyuki Iuchi1, Junichiro Ohori2, Satoshi Kiyama2

  • 1Department of Otolaryngology, Head and Neck Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan. hamoshun@m.kufm.kagoshima-u.ac.jp.

BMC Microbiology
|May 15, 2021
PubMed
Abstract

Insights

Garenoxacin (GRNX) effectively treated cell-invading bacteria like Streptococcus pyogenes and Haemophilus influenzae that cause recurrent tonsillitis. This study found GRNX superior to other tested antibiotics for intracellular bacterial infections.

Area of Science:

  • Otolaryngology
  • Infectious Diseases
  • Microbiology

Background:

  • Recurrent tonsillitis is a common disorder caused by intracellular bacteria.
  • Key pathogens include Streptococcus pyogenes (S. pyogenes) and Haemophilus influenzae.

Purpose of the Study:

  • To evaluate the efficacy of various antibacterial agents against intracellular S. pyogenes and Haemophilus influenzae strains.
  • To identify the most effective antibiotic for treating infections caused by these cell-invading bacteria.

Main Methods:

  • Investigated intracellular invasion of Detroit 562 cells by five nontypeable Haemophilus influenzae (NTHi) and four S. pyogenes strains.
  • Tested the effectiveness of garenoxacin (GRNX), clarithromycin (CAM), amoxicillin (AMPC), cefditoren pivoxil (CDTR-PI), and levofloxacin (LVFX).

Main Results:

  • Both NTHi and S. pyogenes demonstrated full invasion of Detroit 562 cells within 6 hours.
  • Clarithromycin (CAM) showed limited effectiveness against intracellular bacteria.
  • Garenoxacin (GRNX), clarithromycin (CAM), and levofloxacin (LVFX) were effective, while amoxicillin (AMPC) and cefditoren pivoxil (CDTR-PI) were not.

Conclusions:

  • Garenoxacin (GRNX) exhibited the highest efficacy against intracellularly invading bacteria.
  • GRNX represents a promising therapeutic option for recurrent tonsillitis caused by S. pyogenes and NTHi.
Keywords:
Antibacterial agentsGarenoxacinHaemophilus influenzaeStreptococcus pyogenesSusceptibilityemm typing

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