Challenges for accurate susceptibility testing, detection and interpretation of β-lactam resistance phenotypes in Pseudomonas aeruginosa: results from a Spanish multicentre study

To evaluate the proficiency of Spanish laboratories regarding accurate susceptibility testing, detection and interpretation of Pseudomonas aeruginosa β-lactam resistance phenotypes. Thirteen characterized strains were sent to 54 participating centres: clinical strains producing horizontally acquired...

Full description

Saved in:
Bibliographic Details
Published in:Journal of antimicrobial chemotherapy 2013-03, Vol.68 (3), p.619-630
Main Authors: Juan, Carlos, Conejo, M Carmen, Tormo, Nuria, Gimeno, Concha, Pascual, Álvaro, Oliver, Antonio
Format: Article
Language:English
Subjects:
Anti-Bacterial Agents - pharmacology
beta-Lactam Resistance
beta-Lactamases - genetics
beta-Lactamases - secretion
beta-Lactams - pharmacology
Humans
Laboratory Proficiency Testing - organization & administration
Microbial Sensitivity Tests - methods
Phenotype
Pseudomonas aeruginosa - drug effects
Spain
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:To evaluate the proficiency of Spanish laboratories regarding accurate susceptibility testing, detection and interpretation of Pseudomonas aeruginosa β-lactam resistance phenotypes. Thirteen characterized strains were sent to 54 participating centres: clinical strains producing horizontally acquired β-lactamases [extended-spectrum β-lactamases (ESBLs; PER-1 and OXA-161) and class A (GES-5) and B (VIM-2) carbapenemases] and mutants with combinations of chromosomal mechanisms (AmpC, OprD and/or efflux). The centres were requested to evaluate six antipseudomonal β-lactams, provide raw/interpreted clinical categories and detect/infer the resistance mechanisms. Consensus results from reference centres were used to assign minor, major or very major errors (mEs, MEs or VMEs). Vitek2, MicroScan WalkAway and Wider were the most used devices (25%-30% each). CLSI/EUCAST breakpoints were used in 86%/14% of the determinations. Discrepancies exclusively due to the differential application of breakpoints were highest for aztreonam, followed by piperacillin/tazobactam. The lowest percentage of VMEs was for Vitek2, followed by Wider. The highest percentages of VMEs (6%) were for the AmpC-hyperproducing OprD(-) strain and for the GES-5 producer, while among antibiotics the highest percentage of VMEs (22%) involved piperacillin/tazobactam. Appropriate inference of resistance mechanisms was high for the VIM-2-producing strain (83%), but low (
ISSN:1460-2091
DOI:10.1093/jac/dks439