High Rates of Nonsusceptibility to Common Oral Antibiotics in Streptococcus pneumoniae Clinical Isolates From the...

Area of Science:

• Microbiology
• Infectious Diseases
• Pharmacology

Background:

• Antibiotic resistance is a growing concern for treating bacterial pneumonia.
• Streptococcus pneumoniae remains a common cause of community-acquired bacterial pneumonia (CABP).
• Evaluating the in vitro activity of newer antibiotics against prevalent bacterial pathogens is crucial.

Purpose of the Study:

• To assess the in vitro activity of omadacycline against recent clinical isolates of Streptococcus pneumoniae in the United States.
• To compare omadacycline's efficacy with other commonly used antibiotics for respiratory tract infections.

Main Methods:

• Antimicrobial susceptibility testing was performed on 1038 Streptococcus pneumoniae isolates collected between 2019 and 2021.
• Minimum inhibitory concentrations (MICs) were determined for omadacycline, levofloxacin, ceftriaxone, doxycycline, oral penicillin, cefpodoxime, and azithromycin.
• The impact of the Tet(M) resistance gene on antibiotic activity was analyzed.

Main Results:

• High susceptibility rates were observed for omadacycline (99.8%), levofloxacin (99.7%), and ceftriaxone (98.1%).
• Limited activity was noted for doxycycline (80.2%), oral penicillin (63.5%), cefpodoxime (76.8%), and azithromycin (54.4%).
• The Tet(M) gene did not impact omadacycline activity but affected older tetracyclines like doxycycline.

Conclusions:

• Omadacycline demonstrates potent in vitro activity against contemporary Streptococcus pneumoniae isolates.
• Omadacycline represents a valuable therapeutic option for community-acquired bacterial pneumonia, particularly in the context of resistance to other agents.
• The distinct activity profile of omadacycline warrants its consideration in treatment guidelines for S. pneumoniae infections.