β-lactamase-mediated Resistance in MDR-Pseudomonas Aeruginosa from Qatar

Abstract

Background: Anti-pseudomonal b-lactam antibiotics are of paramount importance in the management of Pseudomonas aeruginosa infections. The distribution of b-lactam resistance genes in P. aeruginosa is often closely related to the distribution of certain high-risk international clones. In the present study whole-genome sequencing (WGS) was used to identify the predominant sequence types (STs) and b-lactamase genes in clinical isolates of multidrug-resistant (MDR)-P. aeruginosa from QatarMethods: Microbiological identification and susceptibility tests were performed by automated BD PhoenixTM system and manual Liofilchem MIC Test Strips. Seventy-five MDR-P. aeruginosa isolates were subsequently processed for WGS. Results: Among 75 MDR-P. aeruginosa isolates; the largest proportions of susceptibility were to ceftazidime-avibactam (n=36, 48%), followed by ceftolozane-tazobactam (30, 40%), ceftazidime (n=21, 28%) and aztreonam (n=16, 21.33%). Almost all isolates possessed Class C and Class D b-lactamases (n=72, 96% each), while metallo-β-lactamases were detected in 20 (26.67%) isolates. Eight (40%) metallo-β-lactamases producers were susceptible to aztreonam and did not produce any concomitant extended-spectrum b-lactamases. The most frequent sequence types identified were ST235 (n=16, 21.33%), ST357 (n=8, 10.67%), ST389 and ST1284 (6, 8% each). Nearly all ST235 (15/16; 93.75%) were resistant to all tested b-lactams.Conclusion: MDR-P. aeruginosa isolates from Qatar are highly resistant to antipseudomonal b-lactams. Global high-risk STs are predominant in Qatar and their associated multi-resistant phenotypes are a cause for considerable concern. The molecular epidemiology trends of P. aeruginosa should be surveillance at national levels to track their trends and institute the appropriate control strategies.