Rapid determination of colistin resistance in clinical strains of acinetobacter baumannii by use of the micromax assay
Entity
UAM. Departamento de BiologíaPublisher
American Society for MicrobiologyDate
2013-11-01Citation
10.1128/JCM.01787-13
Journal of Clinical Microbiology 51.11 (2013): 3675-3682
ISSN
0095-1137DOI
10.1128/JCM.01787-13Funded by
This work has been supported by MagicBullet, Xunta de Galicia 10CSA916020PR, and by REIPI, the Spanish Network for Research in Infectious Diseases (Instituto de Salud Carlos III, REIPI RD12/0015) and the Fondo de Investigaciones Sanitarias (FIS PI12/00552) to G.B. M.J.M. is supported by the Subprograma Miguel Servet from the Ministerio de Economía y Competitividad of Spain (CP11/00314). MagicBullet is a project funded by the European Union–Directorate General for Research and Innovation through the Seventh Framework Program for Research and Development (grant agreement 278232) and has been running since 1 January 2012 (36 months’ duration)Project
info:eu-repo/grantAgreement/EC/FP7/278232Editor's Version
http://dx.doi.org/10.1128/JCM.01787-13Subjects
Biología y Biomedicina / BiologíaRights
© 2013, American Society for MicrobiologyAbstract
Colistin is an old antibiotic which has been used as a therapeutic option for carbapenem- and multidrug-resistant Gram-negative bacteria, like Acinetobacter baumannii. This pathogen produces life-threatening infections, mainly in patients admitted to
intensive care units. Rapid detection of resistance to colistin may improve patient outcomes and prevent the spread of resistance. For this purpose, Micromax technology was evaluated in four isogenic A. baumannii strains with known mechanisms of resistance
to colistin and in 66 isolates (50 susceptible and 16 resistant). Two parameters were determined, DNA fragmentation and cell wall damage. To assess DNA fragmentation, cells trapped in a microgel were incubated with a lysing solution to remove the
cell wall, and the released nucleoids were visualized under fluorescence microscopy. Fragmented DNA was observed as spots that diffuse from the nucleoid. To assess cell wall integrity, cells were incubated with a lysis solution which removes only weakened
cell walls, resulting in nucleoid release exclusively in affected cells. A dose-response relationship was demonstrated between colistin concentrations and the percentages of bacteria with DNA fragmentation and cell wall damage, antibiotic effects that
were delayed and less frequent in resistant strains. Receiver operating characteristic (ROC) curves demonstrated that both DNA fragmentation and cell wall damage were excellent parameters for identifying resistant strains. Obtaining<11% of bacteria with
cell wall damage after incubation with 0.5 g/ml colistin identified resistant strains of A. baumannii with 100% sensitivity and 96% specificity. Results were obtained in 3 h 30 min. This is a simple, rapid, and accurate assay for detecting colistin resistance in
A. baumannii, with strong potential value in critical clinical situations
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Google Scholar:Tamayo, María
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Santiso, Rebeca
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Otero, Fátima María
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Bou, Germán
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Lepe, José Antonio
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McConnell, Michael J.
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Cisneros, José Miguel
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Gosalbez Berenguer, José Jaime
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Fernández, José Luís F
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