Related Experiment Video

Updated: Oct 3, 2026

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
08:58

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

Published on: March 3, 2023

OXA-35 is an OXA-10-related beta-lactamase from Pseudomonas aeruginosa

D Aubert1, L Poirel, A B Ali

  • 1Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, 94275 Le Kremlin-Bicêtre, Paris, France.

The Journal of Antimicrobial Chemotherapy
|October 27, 2001
PubMed

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.

More Related Videos

Antibiotic Dereplication Using the Antibiotic Resistance Platform10:49

Antibiotic Dereplication Using the Antibiotic Resistance Platform

Published on: October 17, 2019

Related Concept Videos

Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Inhibitors of Bacterial DNA Synthesis01:28

Inhibitors of Bacterial DNA Synthesis

Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...
Antibiotic Selection01:45

Antibiotic Selection

Researchers use antibiotic resistance genes to identify bacteria that possess a plasmid containing their gene of interest. Antibiotic resistance naturally occurs when a spontaneous DNA mutation creates changes in bacterial genes that eliminate antibiotic activity. Bacteria can share these new resistance genes with their offspring and other bacteria. The overuse and misuse of antibiotics have created a public health crisis, as resistant and multi-resistant bacteria continue to develop.Antibiotic...
Inhibitors of Gram-positive Cell Wall Synthesis01:23

Inhibitors of Gram-positive Cell Wall Synthesis

Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
Gene Regulation in Microbial Communities: Quorum Sensing01:28

Gene Regulation in Microbial Communities: Quorum Sensing

Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...