Prevalence of colistin heteroresistance in carbapenem-resistant Pseudomonas aeruginosa and association with clinical outcomes in patients: an observational study.

Abstract

OBJECTIVES:

To describe the prevalence of colistin heteroresistance in carbapenem-resistant Pseudomonas aeruginosa (CRPA) and evaluate the association with clinical outcomes.

METHODS:

Colistin heteroresistance was evaluated in CRPA isolates collected from patients without cystic fibrosis in Atlanta, Georgia, USA using two definitions: HR1, growth at 4 and 8 mg/L of colistin at a frequency ≥1 × 10-6 the main population; and HR2, growth at a colistin concentration ≥8× the MIC of the main population at a frequency ≥1 × 10-7. A modified population analysis profile (mPAP) technique was compared with reference PAP for detecting heteroresistance. For adults hospitalized at the time of or within 1 week of CRPA culture, multivariable logistic regression estimated the association between heteroresistance and 90 day mortality.

RESULTS:

Of 143 colistin-susceptible CRPA isolates, 8 (6%) met the HR1 definition and 37 (26%) met the HR2 definition. Compared with the reference PAP, mPAP had a sensitivity and specificity of 50% and 100% for HR1 and 32% and 99% for HR2. Of 82 hospitalized patients, 45 (56%) were male and the median age was 63 years (IQR 49-73). Heteroresistance was not associated with 90 day mortality using HR1 (0% in heteroresistant versus 22% in non-heteroresistant group; P = 0.6) or HR2 (12% in heteroresistant versus 24% in non-heteroresistant group; P = 0.4; adjusted OR 0.8; 95% CI 0.2-3.4).

CONCLUSIONS:

Colistin heteroresistance was identified in up to 26% of patients with CRPA in our sample, although the prevalence varied depending on the definition. We did not observe an apparent association between colistin heteroresistance and 90 day mortality.

• Authors: Jessica Howard-Anderson, Michelle Davis, Alexander M Page, Chris W Bower, Gillian Smith, Jesse T Jacob, Dan I Andersson, David S Weiss, Sarah W Satola
• Journal: The Journal of antimicrobial chemotherapy (J Antimicrob Chemother) Vol. 77 Issue 3 Pg. 793-798 (02 23 2022) ISSN: 1460-2091 [Electronic] England
• PMID: 34918135 (Publication Type: Journal Article, Observational Study, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, P.H.S.)
• Copyright: © The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: [email protected].

Chemical References

• Anti-Bacterial Agents
• Carbapenems
• Colistin

Topics

• Adult
• Anti-Bacterial Agents (pharmacology)
• Carbapenems (pharmacology)
• Colistin (pharmacology)
• Humans
• Male
• Middle Aged
• Prevalence
• Pseudomonas aeruginosa