Antimicrobial activity of doripenem tested against prevalent Gram-positive pathogens: results from a global...

Area of Science:

• Infectious Diseases
• Microbiology
• Pharmacology

Background:

• Doripenem is a carbapenem antibiotic approved for complicated urinary tract and intra-abdominal infections.
• Limited data exists on doripenem's activity against Gram-positive pathogens.

Purpose of the Study:

• To evaluate the in vitro activity of doripenem against a global collection of Gram-positive bacteria.
• To assess doripenem's spectrum of activity against staphylococci, enterococci, and streptococci.

Main Methods:

• Reference broth microdilution procedures were used.
• Isolates were collected globally from 2003 to 2007 as part of the Doripenem Surveillance Program.
• Antimicrobial susceptibility testing was performed on Staphylococcus, Enterococcus, and Streptococcus species.

Main Results:

• Doripenem was highly active against oxacillin-susceptible Staphylococcus aureus and coagulase-negative staphylococci (MIC(90) ≤0.06 µg/mL).
• Activity was modest against Enterococcus faecalis (MIC(50) 4 µg/mL) and poor against Enterococcus faecium.
• High activity was observed against Streptococcus pneumoniae (MIC(90) 0.5 µg/mL), beta-hemolytic streptococci (MIC(90) ≤0.06 µg/mL), and viridans group streptococci (MIC(90) 0.25 µg/mL).

Conclusions:

• Doripenem exhibits broad in vitro activity against Gram-positive pathogens, comparable to other carbapenems.
• This activity profile is a significant advantage, particularly against Gram-positive bacteria, complementing its established Gram-negative coverage.
• Doripenem's potency against key Gram-positive species like S. pneumoniae and streptococci warrants consideration in treatment strategies.