Clinical outcomes, molecular epidemiology and resistance mechanisms of multidrug-resistant Pseudomonas aeruginosa isolated from bloodstream infections from Qatar

Ann Med. 2021 Dec;53(1):2345-2353. doi: 10.1080/07853890.2021.2012588.

Abstract

Background: Bloodstream infections (BSIs) caused by multidrug-resistant (MDR)-Pseudomonas aeruginosa are associated with poor clinical outcomes, at least partly due to delayed appropriate antimicrobial therapy. The characteristics of MDR-P. aeruginosa bloodstream isolates have not been evaluated in Qatar. Our study aimed to examine in vitro susceptibility, clinical and molecular characteristics, and mechanisms of resistance of MDR-P. aeruginosa bloodstream isolates from Qatar.

Materials and methods: We included all MDR-P. aeruginosa isolated from blood cultures taken between October 2014 and September 2017. Blood cultures were processed using BD BACTEC™ FX automated system. BD Phoenix™ was used for identification, Liofilchem® MIC Test Strips for MIC determination. Whole-genome sequencing was performed using the Illumina-HiSeq-2000.

Results: Out of 362 P. aeruginosa bloodstream isolates, 16 (4.4%) were MDR. The median patient age was 55 years (range 43-81) and all patients presented with septic shock. Most patients received meropenem (12/16) and/or colistin (10/16). Clinical response was achieved in eight patients, and five patients died within 30-days. MDR-P. aeruginosa isolates belonged to 13 different sequence types. All isolates were non-susceptible to cefepime and ciprofloxacin. The most active agents were colistin (16/16) and aztreonam (10/16). Seven isolates produced blaVIM, and four possessed genes encoding extended-spectrum β-lactamases. Aminoglycoside modifying enzymes were present in 15/16, transferable qnr-mediated quinolone resistance gene was detected in 3/16, and the novel ciprofloxacin modifying enzyme CrpP-encoding gene in one isolate.

Conclusion: MDR-P. aeruginosa BSIs are relatively uncommon in Qatar but are highly resistant, harbour multiple resistance genes, and are commonly associated with unfavourable clinical outcomes. Colistin was the only agent with consistent activity against the study isolates.Key messagesMDR-P. aeruginosa constituted <5% of P. aeruginosa blood isolates over three years.Typical risk factors for MDR infections were highly prevalent in the study population and overall clinical outcomes are consistent with those previously reported.Colistin was the only agent with consistent antibacterial activity against the study isolates.

Keywords: Bacteraemia; MDR; Pseudomonas aeruginosa; Qatar.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use
  • Drug Resistance, Multiple, Bacterial / genetics
  • Humans
  • Microbial Sensitivity Tests
  • Middle Aged
  • Molecular Epidemiology
  • Pseudomonas Infections* / drug therapy
  • Pseudomonas Infections* / epidemiology
  • Pseudomonas Infections* / microbiology
  • Pseudomonas aeruginosa / genetics
  • Qatar / epidemiology
  • Sepsis* / drug therapy
  • Sepsis* / epidemiology

Substances

  • Anti-Bacterial Agents

Grants and funding

Open Access funding provided by the Qatar National Library. The publication is supported by a grant from Qatar National Library. The study was funded by an internal research grant [IRGC-01–51-033 to E. B. I.] from the Medical Research Centre at Hamad Medical Corporation, Doha, Qatar, and a National Priorities Research Program (NPRP) grant [NPRP12S-0219-190109 to A. A. S.] from the Qatar National Research Fund (a member of Qatar Foundation). Support was also provided by the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas) [grant 219-2014-837 to J. J.]. The funders were not involved in the conduct of the study, the preparation of the manuscript, or the decision to submit the manuscript for publication. The findings achieved herein are solely the responsibility of the author[s].