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OXA-35 is an OXA-10-related beta-lactamase from Pseudomonas aeruginosa
1Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, 94275 Le Kremlin-Bicêtre, Paris, France.
Abstract:
Pseudomonas aeruginosa clinical isolate PA35 is resistant to amino- and ureido-penicillins, has intermediate susceptibility to cefsulodin, cefepime and aztreonam, and is susceptible to imipenem and ceftazidime. Cloning and sequencing revealed a new beta-lactamase variant, OXA-35, sharing 96% amino acid identity with OXA-10. OXA-35 displays a restricted-substrate hydrolysis profile with improved hydrolysis of amoxicillin and cloxacillin compared with OXA-10. OXA-35 differs from derivatives OXA-19 and OXA-28 by one amino acid substitution and may be a progenitor of these OXA-13-like extended-spectrum beta-lactamases.
Insights
A new beta-lactamase, OXA-35, was identified in Pseudomonas aeruginosa PA35. This enzyme confers resistance to certain penicillins and may be a progenitor of OXA-13-like extended-spectrum beta-lactamases.
Area of Science:
- Microbiology
- Biochemistry
- Genetics
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen known for its intrinsic and acquired antibiotic resistance.
- Beta-lactamases are key enzymes responsible for the hydrolysis of beta-lactam antibiotics, contributing significantly to bacterial resistance.
- The emergence of novel beta-lactamase variants necessitates continuous surveillance and characterization to understand resistance mechanisms.
Purpose of the Study:
- To identify and characterize the beta-lactamase responsible for the observed antibiotic resistance in Pseudomonas aeruginosa clinical isolate PA35.
- To determine the genetic basis and substrate hydrolysis profile of the novel beta-lactamase variant.
Main Methods:
- Antibiotic susceptibility testing of Pseudomonas aeruginosa PA35.
- Cloning and sequencing of the beta-lactamase gene from the clinical isolate.
- Biochemical characterization of the purified beta-lactamase to determine its substrate hydrolysis profile.
Main Results:
- Pseudomonas aeruginosa PA35 exhibited resistance to amino- and ureido-penicillins and intermediate susceptibility to cefsulodin, cefepime, and aztreonam.
- A novel beta-lactamase, designated OXA-35, was identified and found to share 96% amino acid identity with OXA-10.
- OXA-35 demonstrated a restricted substrate hydrolysis profile with enhanced hydrolysis of amoxicillin and cloxacillin compared to OXA-10.
Conclusions:
- The novel beta-lactamase OXA-35 contributes to the resistance phenotype of Pseudomonas aeruginosa PA35.
- OXA-35 represents a distinct variant within the OXA beta-lactamase family, potentially serving as a progenitor for OXA-13-like extended-spectrum beta-lactamases.