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In vitro activity of LY333328 against vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus,
R Patel1, M S Rouse, K E Piper
1Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, Minnesota 55902, USA.
Abstract:
We report the activity of LY333328 against 35 clinical isolates of vancomycin-resistant enterococci (including organisms carrying the vanA, vanB, vanC-1, and vanC-2/3 genes, as determined by PCR), 33 clinical isolates of methicillin-resistant S. aureus, and 29 clinical isolates of high-level penicillin-resistant S. pneumoniae. All isolates of vancomycin-resistant enterococci were inhibited by 2 micrograms/mL LY333328, and 8 micrograms/mL LY333328 was bactericidal against all isolates tested. All isolates of methicillin-resistant S. aureus were inhibited by 1 microgram/mL LY333328, and 4 micrograms/mL LY333328 was bactericidal against all methicillin-resistant S. aureus isolates tested. All isolates of penicillin-resistant S. pneumoniae were inhibited by < 0.125 microgram/mL LY333328, and 0.25 microgram/mL LY333328 was bactericidal against all S. pneumoniae isolates tested. LY333328 is a promising new glycopeptide antimicrobial agent.
Insights
LY333328 effectively inhibits and kills resistant bacteria, including vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and penicillin-resistant Streptococcus pneumoniae. This new glycopeptide shows significant antimicrobial activity against challenging clinical isolates.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Antimicrobial resistance is a growing global health threat.
- Emergence of multidrug-resistant bacteria necessitates novel therapeutic agents.
- Glycopeptides are an important class of antibiotics used to treat serious Gram-positive infections.
Purpose of the Study:
- To evaluate the in vitro activity of LY333328 against key resistant bacterial pathogens.
- To determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of LY333328.
- To assess the potential of LY333328 as a new antimicrobial agent.
Main Methods:
- Testing LY333328 against 35 clinical isolates of vancomycin-resistant enterococci (VRE).
- Evaluating LY333328 against 33 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA).
- Assessing LY333328 activity against 29 clinical isolates of penicillin-resistant Streptococcus pneumoniae (PRSP).
- Determining vancomycin resistance genes (vanA, vanB, vanC-1, vanC-2/3) in VRE using PCR.
Main Results:
- All VRE isolates were inhibited by 2 µg/mL LY333328 and killed by 8 µg/mL.
- All MRSA isolates were inhibited by 1 µg/mL LY333328 and killed by 4 µg/mL.
- All PRSP isolates were inhibited by <0.125 µg/mL LY333328 and killed by 0.25 µg/mL.
Conclusions:
- LY333328 demonstrates potent broad-spectrum activity against clinically relevant resistant Gram-positive bacteria.
- The compound exhibits both bacteriostatic and bactericidal effects at low concentrations.
- LY333328 represents a promising novel glycopeptide antimicrobial agent for treating resistant infections.