Related Experiment Videos
Imipenem/gentamicin and imipenem/rifampin against methicillin-resistant Staphylococcus aureus
1Department of Internal Medicine, St. Elizabeth Hospital Medical Center, Youngstown, Ohio.
Abstract:
The combinations of imipenem with gentamicin and imipenem with rifampin were studied by the time-kill method against 20 strains of methicillin-resistant Staphylococcus aureus. Twelve strains were resistant to imipenem, 18 resistant to gentamicin, 5 resistant to both imipenem and gentamicin and 5 resistant to imipenem, gentamicin and rifampin. Imipenem/gentamicin was synergistic against 1 strain and antagonistic against another strain. Imipenem/rifampin was synergistic against 4 strains and antagonistic against 3 other strains.
Insights
Investigating antibiotic combinations against methicillin-resistant Staphylococcus aureus (MRSA) showed limited synergy. Imipenem/gentamicin and imipenem/rifampin combinations demonstrated minimal effectiveness against resistant MRSA strains.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant challenge in healthcare settings due to its resistance to multiple antibiotics.
- The emergence of multidrug-resistant MRSA necessitates the exploration of novel therapeutic strategies, including antibiotic combinations.
Purpose of the Study:
- To evaluate the in vitro efficacy of imipenem combined with gentamicin or rifampin against clinical isolates of MRSA.
- To determine the synergistic, additive, or antagonistic effects of these antibiotic combinations using time-kill assays.
Main Methods:
- Time-kill assays were performed to assess the activity of imipenem/gentamicin and imipenem/rifampin combinations.
- The study included 20 strains of MRSA, with varying resistance profiles to imipenem, gentamicin, and rifampin.
Main Results:
- Imipenem/gentamicin exhibited synergy against 1 strain and antagonism against another.
- Imipenem/rifampin showed synergy against 4 strains and antagonism against 3 strains.
- A significant proportion of tested MRSA strains displayed resistance to the individual antibiotics, including imipenem.
Conclusions:
- The combination of imipenem with either gentamicin or rifampin demonstrated limited synergistic activity against the tested MRSA strains.
- The high prevalence of resistance to individual agents complicates the effectiveness of these antibiotic combinations in treating MRSA infections.