Detection of colistin heteroresistance in Acinetobacter baumannii from blood and respiratory isolates

Copyright © 2018 Elsevier Inc. All rights reserved..

Polymyxins are one of the last-line antibiotics for multidrug-resistant Acinetobacter baumannii. Reports have demonstrated the emergence of colistin heteroresistance in A. baumannii, which can complicate assessment of minimum inhibitory concentrations and promote resistance to colistin. We aimed to determine the presence of colistin heteroresistance in A. baumannii isolates and correlate the results with clinical and microbiological outcomes via a retrospective study of 24 adult patients: 12 blood and 12 invasive respiratory cultures positive for colistin-susceptible A. baumannii between 1 January 2013 and 31 July 2015. Heteroresistance testing was performed by plating a 100-μL bacterial cell suspension on Mueller-Hinton agar plates containing 0, 1, 2, and 4 μg/mL colistin, and assessing for growth at 24 and 48 h. Colistin heteroresistance was exhibited in 83% of isolates. Median age was 56 [43-65] years, 10 (42%) patients resided at a facility prior to admission, 5 (21%) had a chronic tracheostomy, 18 (75%) were in the intensive care unit at the time of culture collection, and median infection-related length of stay was 12 [7-15] days. Clinical and microbiological cures were achieved in 75% of patients. Overall infection-related mortality was 21%. Our study demonstrated a high rate of colistin heteroresistance in clinical isolates of colistin-susceptible A. baumannii, although this was not associated with suboptimal clinical outcomes due to the use of aggressive colistin dosing and combination therapy. Further studies are needed to establish the association between in vitro colistin heteroresistance and clinical and microbiological outcomes.

Medienart:

E-Artikel

Erscheinungsjahr:

2018

Erschienen:

2018

Enthalten in:

Zur Gesamtaufnahme - volume:91

Enthalten in:

Diagnostic microbiology and infectious disease - 91(2018), 2 vom: 01. Juni, Seite 194-198

Sprache:

Englisch

Beteiligte Personen:

Srinivas, Pavithra [VerfasserIn]
Hunt, Lauren N [VerfasserIn]
Pouch, Stephanie M [VerfasserIn]
Thomas, Keelie [VerfasserIn]
Goff, Debra A [VerfasserIn]
Pancholi, Preeti [VerfasserIn]
Balada-Llasat, Joan-Miquel [VerfasserIn]
Bauer, Karri A [VerfasserIn]

Links:

Volltext

Themen:

Acinetobacter baumannii
Anti-Bacterial Agents
Colistin
Colistin heteroresistance
Journal Article
Multidrug-resistant Gram-negative organisms
Polymyxin B
Polymyxins
Z67X93HJG1

Anmerkungen:

Date Completed 04.10.2018

Date Revised 04.10.2018

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.diagmicrobio.2018.01.028

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM281408904