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Diverse potential of beta-lactamase inhibitors to induce class I enzymes
1Department of Medical Microbiology, Creighton University School of Medicine, Omaha, Nebraska 68178.
Abstract:
The ability of various beta-lactamase inhibitors to induce class I beta-lactamases was assessed. Clavulanate was the most active compound, inducing Morganella morganii, Aeromonas caviae, and Enterobacter aerogenes over a broad concentration range and Citrobacter freundii, Pseudomonas aeruginosa, and Serratia marcescens at high concentrations. Disk approximation tests paralleled these results, with clavulanate, but not sulbactam or tazobactam, antagonizing the activity of several beta-lactams against these organisms.
Insights
Clavulanate effectively induces beta-lactamase production in several bacteria, including Morganella morganii and Enterobacter aerogenes. This induction antagonized beta-lactam activity, highlighting potential resistance mechanisms.
Area of Science:
- Microbiology
- Pharmacology
- Antimicrobial Resistance
Background:
- Beta-lactamase enzymes are a primary mechanism of bacterial resistance to beta-lactam antibiotics.
- Understanding how beta-lactamase inhibitors (BLIs) affect beta-lactamase production is crucial for combating antimicrobial resistance.
Purpose of the Study:
- To evaluate the capacity of different beta-lactamase inhibitors to induce class I beta-lactamases in various bacterial species.
- To determine the comparative efficacy of clavulanate, sulbactam, and tazobactam in this regard.
Main Methods:
- Bacterial cultures of Morganella morganii, Aeromonas caviae, Enterobacter aerogenes, Citrobacter freundii, Pseudomonas aeruginosa, and Serratia marcescens were exposed to varying concentrations of beta-lactamase inhibitors.
- Induction of class I beta-lactamases was quantified.
- Disk approximation tests were performed to assess the impact of BLIs on the activity of beta-lactam antibiotics against these bacteria.
Main Results:
- Clavulanate demonstrated significant activity in inducing class I beta-lactamases across a wide concentration range in M. morganii, A. caviae, and E. aerogenes.
- Higher concentrations of clavulanate were required to induce beta-lactamases in C. freundii, P. aeruginosa, and S. marcescens.
- Disk approximation tests confirmed that clavulanate, unlike sulbactam and tazobactam, antagonized the activity of several beta-lactams against the tested organisms.
Conclusions:
- Clavulanate is a potent inducer of class I beta-lactamases in a range of Gram-negative bacteria.
- The induction of beta-lactamases by clavulanate can lead to antagonism of beta-lactam antibiotic efficacy, contributing to treatment challenges.