Ceftazidime/avibactam resistance is associated with PER-3-producing ST309 lineage in Chilean clinical isolates of non-carbapenemase producing Pseudomonas aeruginosa

Front Cell Infect Microbiol. 2024 Jun 5:14:1410834. doi: 10.3389/fcimb.2024.1410834. eCollection 2024.

Abstract

Introduction: Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant Pseudomonas aeruginosa, particularly those that are carbapenem resistant. CZA resistance in P. aeruginosa producing PER, a class A extended-spectrum β-lactamase, has been well documented in vitro. However, data regarding clinical isolates are scarce. Our aim was to analyze the contribution of PER to CZA resistance in non-carbapenemase-producing P. aeruginosa clinical isolates that were ceftazidime and/or carbapenem non-susceptible.

Methods: Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while bla PER gene was screened through PCR. All PER-positive isolates and five PER-negative isolates were analyzed through Whole Genome Sequencing. The mutational resistome associated to CZA resistance was determined through sequence analysis of genes coding for PBPs 1b, 3 and 4, MexAB-OprM regulators MexZ, MexR, NalC and NalD, AmpC regulators AmpD and AmpR, and OprD porin. Loss of bla PER-3 gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics.

Results: Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried bla PER. One isolate carried bla PER but was CZA-susceptible. PER-producing isolates had significantly higher MICs for CZA, amikacin, gentamicin, ceftazidime, meropenem and ciprofloxacin than non-PER-producing isolates. All PER-producing isolates were ST309 and their bla PER-3 gene was associated to ISCR1, an insertion sequence known to mobilize adjacent DNA. PER-negative isolates were classified as ST41, ST235 (two isolates), ST395 and ST253. PER-negative isolates carried genes for narrow-spectrum β-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of bla PER-3 gene restored susceptibility to CZA, ceftolozane/tazobactam and other β-lactamsin the in vitro evolved isolate.

Discussion: PER-3-producing ST309 P. aeruginosa is a successful multidrug-resistant clone with blaPER-3 gene implicated in resistance to CZA and other β-lactams.

Keywords: PER-3 extended-spectrum β-lactamase; Pseudomonas aeruginosa; blaPER-3 gene; ceftazidime/avibactam resistance; mutations conferring CZA resistance.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Azabicyclo Compounds / pharmacology
  • Bacterial Proteins* / genetics
  • Bacterial Proteins* / metabolism
  • Ceftazidime* / pharmacology
  • Chile
  • Drug Combinations
  • Drug Resistance, Multiple, Bacterial* / genetics
  • Humans
  • Microbial Sensitivity Tests
  • Mutation
  • Pseudomonas Infections* / microbiology
  • Pseudomonas aeruginosa* / drug effects
  • Pseudomonas aeruginosa* / genetics
  • Whole Genome Sequencing
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism

Substances

  • Anti-Bacterial Agents
  • avibactam, ceftazidime drug combination
  • Azabicyclo Compounds
  • Bacterial Proteins
  • beta-Lactamases
  • carbapenemase
  • Ceftazidime
  • Drug Combinations

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by research funds from SENTRY (Antimicrobial Resistance Surveillance Program), the Red de Salud UC-Christus and the Department of Clinical Laboratories at the School of Medicine of Pontificia Universidad Católica de Chile. Funding for whole-genome sequencing was obtained from the Key Technology Partnership Program from the University of Technology Sydney, and from Instituto de Ciencias e Innovación en Medicina (ICIM), Facultad de Medicina, Universidad del Desarrollo. Santiago, Chile. Pfizer provided avibactam in the context of a Pure Compound Grant (PCG) ID#75444555 awarded to AW. This work was partially funded by the Agencia Nacional de Investigación y Desarrollo (ANID, Chile) through FONDECYT Postoctoral Grant N°3200798 awarded to MA-R. JU was funded by ANID-Fondecyt Regular 1221209 and ANID-Anillo ATE 220061.