Pseudomonas aeruginosa, a ubiquitous opportunistic pathogen considered one of the
paradigms of antimicrobial resistance, is among the main causes of hospital-acquired
and chronic infections associated with significant morbidity and mortality. This growing
threat results from the extraordinary capacity of P. aeruginosa to develop antimicrobial
resistance through chromosomal mutations, the increasing prevalence of transferable
resistance determinants (such as the carbapenemases and the extended spectrum β-lactamases),
and the global expansion of epidemic lineages. The general objective of this initiative
is to provide a comprehensive update of P. aeruginosa resistance mechanisms, especially
for the extensively drug-resistant (XDR)/difficult to treat resistance (DTR) international
high-risk epidemic lineages, and how the recently approved β-lactams and β-lactam/β-lactamase
inhibitor combinations may affect resistance mechanisms and the definition of susceptibility
profiles.To address this challenge, the European Study Group for Antimicrobial Resistance
Surveillance (ESGARS) from the European Society of Clinical Microbiology and Infectious
Diseases (ESCMID) launched the "Improving Surveillance of Antibiotic-Resistant Pseudomonas
aeruginosa in Europe" (ISARPAE) initiative in 2022, supported by the Joint programming
initiative on antimicrobial resistance (JPIAMR) network call and included a panel
of over 40 researchers from 18 European Countries. Thus, an ESGARS-ISARPAE position
paper was designed and the final version agreed after four rounds of revision and
discussion by all panel members.To provide an update on (i) the emerging resistance
mechanisms to classical and novel antipseudomonal agents, with a particular focus
on β-lactams, (ii) the susceptibility profiles associated with the most relevant β-lactam
resistance mechanisms, (iii) the impact of the novel agents and resistance mechanisms
on the definitions of resistance profiles and (iv) the globally expanding XDR/DTR
high-risk lineages and their association with transferable resistance mechanisms.The
evidence presented herein can be used for coordinated epidemiological surveillance
and decision-making at the European and global level.
