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Reduced susceptibility to aztreonam-avibactam conferred by acquired AmpC-type ß-lactamases in PBP3-modified Escherichia coli.
Helsens, Nicolas; Sadek, Mustafa; Le Terrier, Christophe; Poirel, Laurent; Nordmann, Patrice.
Affiliation
  • Helsens N; Clinical Microbiology Unit, Pasteur Institute of Lille, 1 Rue du Professeur Calmette, 59000, Lille, France. nicolas.helsens@pasteur-lille.fr.
  • Sadek M; Department of Food Hygiene and Control, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt.
  • Le Terrier C; Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
  • Poirel L; Division of Intensive Care Unit, University Hospitals of Geneva, Geneva, Switzerland.
  • Nordmann P; Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
Article in En | MEDLINE | ID: mdl-38319508
ABSTRACT

PURPOSE:

Carbapenemase-producing Enterobacterales are a growing threat, and very few therapeutic options remain active against those multidrug resistant bacteria. Aztreonam is the molecule of choice against metallo-beta-lactamases (MBL) producers since it is not hydrolyzed by those enzymes, but the co-production of acquired plasmidic cephalosporinases or extended-spectrum ß-lactamases leading to aztreonam resistance may reduce the efficacy of this molecule. Hence, the development of the aztreonam-avibactam (AZA) combination provides an interesting therapeutic alternative since avibactam inhibits the activity of both cephalosporinases and extended-spectrum ß-lactamases. However, structural modifications of penicillin binding protein PBP3, the target of aztreonam, may lead to reduced susceptibility to aztreonam-avibactam.

METHODS:

Here the impact of various plasmid-encoded AmpC-type ß-lactamases (ACC-1, ACT-7, ACT-17, CMY-2, CMY-42, DHA-1, FOX-1, and FOX-5) on susceptibility to aztreonam-avibactam was evaluated using isogenic E. coli MG1655 strains harboring insertions in PBP3 (YRIN and YRIK). The inhibitory activity of various ß-lactamase inhibitors (clavulanic acidtazobactam, avibactam, relebactam, and vaborbactam) were also compared against these enzymes.

RESULTS:

Hence, we showed that reduced susceptibility to AZA was due to the combined effect of both AmpC production and amino acid insertions in PBP3. The highest resistance level was achieved in strains possessing the insertions in PBP3 in association with the production of ACT-7, ACC-1, or CMY-42.

CONCLUSION:

Although none of the recombinant strains tested displayed clinical resistance to aztreonam-avibactam, our data emphasize that the occurrence of such profile might be of clinical relevance for MBL-producing strains.
Key words

Full text: 1 Database: MEDLINE Language: En Journal: Eur J Clin Microbiol Infect Dis Journal subject: DOENCAS TRANSMISSIVEIS / MICROBIOLOGIA Year: 2024 Type: Article Affiliation country: France

Full text: 1 Database: MEDLINE Language: En Journal: Eur J Clin Microbiol Infect Dis Journal subject: DOENCAS TRANSMISSIVEIS / MICROBIOLOGIA Year: 2024 Type: Article Affiliation country: France