CEM-101, a novel fluoroketolide: antimicrobial activity against a diverse collection of Gram-positive and Gram-negative bacteria

Diagn Microbiol Infect Dis. 2010 Apr;66(4):393-401. doi: 10.1016/j.diagmicrobio.2009.10.013.


CEM-101 is a novel fluoroketolide with reported high potency against diverse groups of Gram-positive (Micrococcus spp., viridans group streptococci, Corynebacterium spp. Listeria monocytogenes, Clostridium spp., etc.) and Gram-negative bacteria (Neisseria gonorrhoeae, Campylobacter jejuni, Helicobacter pylori, Bacteroides fragilis, Shigella spp., etc.), including mycoplasma and ureaplasma, as well as bacteria commonly associated with community-acquired respiratory tract infections and skin and skin structure infections. In this study, CEM-101 and comparator antimicrobials were tested against a collection of very low prevalence aerobic and anaerobic bacteria collected via the SENTRY Antimicrobial Surveillance Program platform. CEM-101 was highly active against all Gram-positive organisms (MIC(50), 0.015 microg/mL) as compared with telithromycin (MIC(50), 0.06 microg/mL), clarithromycin (MIC(50), 0.12 microg/mL), and erythromycin (MIC(50), 0.25 microg/mL). Among Gram-negative pathogens, CEM-101 also displayed a high potency against most strains (MIC(50), 4 microg/mL) but was found to be equivalent or less active when compared with other antimicrobials tested with MIC(50) values ranging from < or =0.12 microg/mL for levofloxacin to 8 microg/mL for telithromycin. Among the strict anaerobic species, CEM-101 activity mirrored that of the aerobic species: high activity against the Gram-positive anaerobes (MIC(50) results ranging from < or =0.03 microg/mL to 0.12 microg/mL) and equivalent or less susceptible against Gram-negative anaerobes. Our in vitro antimicrobial susceptibility results for CEM-101 demonstrate better activity compared with other MLS(B) class agents among a diverse group of uncommonly isolated bacterial pathogens; these results provide an impetus for possible expanded indications during Phase 2 and 3 clinical trials.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacteria, Aerobic / drug effects
  • Bacteria, Anaerobic / drug effects
  • Bacterial Infections / microbiology
  • Gram-Negative Bacteria / drug effects*
  • Gram-Negative Bacteria / isolation & purification
  • Gram-Positive Bacteria / drug effects*
  • Gram-Positive Bacteria / isolation & purification
  • Humans
  • Macrolides / pharmacology*
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Triazoles / pharmacology*


  • Anti-Bacterial Agents
  • Macrolides
  • Triazoles
  • solithromycin