title: Escherichia coli Overexpressing a Baeyer-Villiger Monooxygenase from Acinetobacter radioresistens Becomes Resistant to Imipenem.
abstract: Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance.
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Minerdi
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy.
authors.forename: Ivan
authors.initials: I
authors.lastname: Zgrablic
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Castrignanò
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Catucci
authors.affiliation: Department of Molecular Biotechnology and Health, University of Torino, Turin, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Medana
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy.
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Terlizzi
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Gribaudo
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Gilardi
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Turin, Italy sheila.sadeghi@unito.it.
authors.forename: Sheila J
authors.initials: SJ
authors.lastname: Sadeghi
mesh_terms: D000150:Acinetobacter / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001549:Benzamides / Q000378:metabolism; D001711:Biotransformation; D003001:Cloning, Molecular; D052978:Disk Diffusion Antimicrobial Tests; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D015870:Gene Expression; D015378:Imipenem / Q000378:metabolism* / Q000494:pharmacology; D060847:Metabolic Engineering; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D010879:Piperazines / Q000378:metabolism; D011720:Pyrazoles / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D003521:Cyclopropanes; D011743:Pyrimidines
chemical_list: D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D001426:Bacterial Proteins; D001549:Benzamides; D015378:Imipenem; D006899:Mixed Function Oxygenases; D009249:NADP; D010879:Piperazines; D011720:Pyrazoles; D011994:Recombinant Proteins; C484810:tozasertib; D003521:Cyclopropanes; D011743:Pyrimidines; C523797:danusertib