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Detection of beta-lactamase production and enzyme profiles in Enterobacteriaceae isolated in Moldova
A Poiată1, R Gheorghiu, D Diculencu
1Departament of Microbiology, University of Medicine and Pharmacy, Iaşi.
Abstract:
In our study, out of 449 Enterobacteriaceae strains isolated between 1985 and 1990, 16 strains (3 Proteus, 6 nontyphoidal Salmonella, 7 Escherichia coli) were resistant both to Ampicillin- Sulbactam and Amoxycillin-Clavulanic acid associations. The activity profiles of the beta-lactamases produced by these resistant strains are described. Sarcina lutea ATCC 9341 was used as test strain. The effect of the enzymatic filtrate against beta-lactam antibiotics: Ampicillin, Cloxacillin, Cefadroxil, Cefuroxime, Cefotaxime, Ceftriaxone, was followed up. The enzyme types were established according to the ability of inactivating the tested antibiotics. Penicillins and cephalosporins were inactivated by these enzymes, except for Carbenicillin and Oxacillin. These beta-lactamases were resistant to Sulbactam and Clavulanic acid. In the studied Salmonella strains they are plasmidic codified, demonstrating that they belong to a new beta-lactamase class.
Insights
Sixteen Enterobacteriaceae strains exhibited resistance to ampicillin-sulbactam and amoxycillin-clavulanic acid. The study characterized novel plasmid-encoded beta-lactamases in Salmonella strains, resistant to these antibiotics.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Antibiotic resistance is a growing global health concern.
- Beta-lactam antibiotics, including penicillins and cephalosporins, are widely used.
- Emergence of beta-lactamases poses a significant threat to antibiotic efficacy.
Purpose of the Study:
- To characterize the beta-lactamase activity of Enterobacteriaceae strains resistant to ampicillin-sulbactam and amoxycillin-clavulanic acid.
- To identify the genetic basis and enzyme class of these novel beta-lactamases.
Main Methods:
- Isolation and identification of Enterobacteriaceae strains.
- Antimicrobial susceptibility testing against beta-lactam antibiotics and their inhibitors.
- Enzymatic assays using Sarcina lutea and enzymatic filtrates.
- Determination of beta-lactamase enzyme types based on antibiotic inactivation profiles.
- Plasmid analysis to determine genetic linkage.
Main Results:
- Sixteen out of 449 Enterobacteriaceae strains showed resistance to both ampicillin-sulbactam and amoxycillin-clavulanic acid.
- The resistant strains produced beta-lactamases that inactivated penicillins and cephalosporins, except carbenicillin and oxacillin.
- These novel beta-lactamases were resistant to sulbactam and clavulanic acid.
- In Salmonella strains, the beta-lactamases were plasmid-encoded.
Conclusions:
- A new class of plasmid-encoded beta-lactamases conferring resistance to beta-lactamase inhibitors has emerged in Enterobacteriaceae.
- These findings highlight the need for continuous surveillance of antibiotic resistance mechanisms.
- Further research is warranted to understand the prevalence and clinical implications of these novel enzymes.