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Effect of non-beta-lactam antibiotics on penicillin-binding protein synthesis of Enterococcus hirae ATCC 9790
A Grossato1, R Sartori, R Fontana
1Institute of Microbiology, University of Padua, Italy.
Abstract:
Fosfomycin, bacitracin and vancomycin in combination with penicillin exhibit a synergic effect against Enterococcus hirae ATCC 9790. This strain, when incubated in presence of the MIC of non-beta-lactam antibiotics, showed an alternated pattern of PBPs. Bacitracin and vancomycin caused a decrease in the density of all PBPs while fosfomycin only reduced that of PBP 6. It is suggested that the observed synergy is a consequence of the inhibition of PBP synthesis by antibiotics which act on the early stages of peptidoglycan synthesis prior to the formation of cross-links.
Insights
Certain antibiotics like fosfomycin, bacitracin, and vancomycin show synergistic effects with penicillin against Enterococcus hirae. This synergy may stem from their impact on penicillin-binding proteins (PBPs) crucial for bacterial cell wall synthesis.
Area of Science:
- Microbiology
- Antibiotic Resistance
- Bacterial Cell Wall Synthesis
Background:
- Enterococcus hirae is a bacterium relevant in clinical settings.
- Antibiotic synergy can enhance treatment efficacy and combat resistance.
- Penicillin-binding proteins (PBPs) are essential targets for beta-lactam antibiotics.
Purpose of the Study:
- To investigate the synergistic effects of fosfomycin, bacitracin, and vancomycin in combination with penicillin against Enterococcus hirae ATCC 9790.
- To elucidate the impact of these non-beta-lactam antibiotics on penicillin-binding proteins (PBPs) in Enterococcus hirae.
Main Methods:
- Testing synergistic effects of antibiotic combinations against Enterococcus hirae.
- Incubating Enterococcus hirae with the minimum inhibitory concentration (MIC) of non-beta-lactam antibiotics.
- Analyzing alterations in penicillin-binding protein (PBP) patterns using gel electrophoresis or similar techniques.
Main Results:
- Fosfomycin, bacitracin, and vancomycin demonstrated synergistic activity with penicillin against Enterococcus hirae.
- Incubation with non-beta-lactam antibiotics altered the pattern of PBPs.
- Bacitracin and vancomycin reduced the density of all PBPs, while fosfomycin specifically reduced PBP 6 density.
Conclusions:
- The observed synergy between fosfomycin, bacitracin, vancomycin, and penicillin against Enterococcus hirae is likely due to the inhibition of PBP synthesis.
- These antibiotics target early stages of peptidoglycan synthesis, preceding cross-link formation.
- Understanding PBP alterations provides insights into novel antibacterial strategies.