Mechanisms of Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa : Results of the GERPA Multicenter Study

Copyright © 2021 American Society for Microbiology..

Resistance mechanisms of Pseudomonas aeruginosa to ceftolozane/tazobactam (C/T) were assessed on a collection of 420 nonredundant strains nonsusceptible to ceftazidime (MIC > 8 μg/ml) and/or imipenem (>4 μg/ml), collected by 36 French hospital laboratories over a one-month period (the GERPA study). Rates of C/T resistance (MIC > 4/4 μg/ml) were equal to 10% in this population (42/420 strains), and 23.2% (26/112) among the isolates resistant to both ceftazidime and imipenem. A first group of 21 strains (50%) was found to harbor various extended-spectrum β-lactamases (1 OXA-14; 2 OXA-19; 1 OXA-35; 1 GES-9; and 3 PER-1), carbapenemases (2 GES-5; 1 IMP-8; and 8 VIM-2), or both (1 VIM-2/OXA-35 and 1 VIM-4/SHV-2a). All the strains of this group belonged to widely distributed epidemic clones (ST111, ST175, CC235, ST244, ST348, and ST654), and were highly resistant to almost all the antibiotics tested except colistin. A second group was composed of 16 (38%) isolates moderately resistant to C/T (MICs from 8/4 to 16/4 μg/ml), of which 7 were related to international clones (ST111, ST253, CC274, ST352, and ST386). As demonstrated by targeted mass spectrometry, cloxacillin-based inhibition tests, and gene blaPDC deletion experiments, this resistance phenotype was correlated with an extremely high production of cephalosporinase PDC. In part accounting for this strong PDC upregulation, genomic analyses revealed the presence of mutations in the regulator AmpR (D135N/G in 6 strains) and enzymes of the peptidoglycan recycling pathway, such as AmpD, PBP4, and Mpl (9 strains). Finally, all of the 5 (12%) remaining C/T-resistant strains (group 3) appeared to encode PDC variants with mutations known to improve the hydrolytic activity of the β-lactamase toward ceftazidime and C/T (F147L, ΔL223-Y226, E247K, and N373I). Collectively, our results highlight the importance of both intrinsic and transferable mechanisms in C/T-resistant P. aeruginosa Which mutational events lead some clinical strains to massively produce the natural cephalosporinase PDC remains incompletely understood.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:65

Enthalten in:

Antimicrobial agents and chemotherapy - 65(2021), 2 vom: 20. Jan.

Sprache:

Englisch

Beteiligte Personen:

Fournier, Damien [VerfasserIn]
Carrière, Romain [VerfasserIn]
Bour, Maxime [VerfasserIn]
Grisot, Emilie [VerfasserIn]
Triponney, Pauline [VerfasserIn]
Muller, Cédric [VerfasserIn]
Lemoine, Jérôme [VerfasserIn]
Jeannot, Katy [VerfasserIn]
Plésiat, Patrick [VerfasserIn]
GERPA Study Group [VerfasserIn]

Links:

Volltext

Themen:

37A4IES95Q
9M416Z9QNR
Anti-Bacterial Agents
Antibiotic resistance
Beta-Lactamases
Ceftazidime
Ceftolozane
Cephalosporins
Drug resistance mechanisms
EC 3.5.2.6
Journal Article
Multicenter Study
Pseudomonas aeruginosa
SE10G96M8W
Tazobactam

Anmerkungen:

Date Completed 17.06.2021

Date Revised 21.07.2021

published: Electronic-Print

Citation Status MEDLINE

doi:

10.1128/AAC.01117-20

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM317667610