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PLoS One. 2017 Aug 31;12(8):e0183899. doi: 10.1371/journal.pone.0183899. eCollection 2017.

Semi-quantitative MALDI-TOF for antimicrobial susceptibility testing in Staphylococcus aureus.

Author information

1
Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Disease, Fort Detrick, Maryland, United States of America.

Abstract

Antibiotic resistant bacterial infections are a significant problem in the healthcare setting, in many cases requiring the rapid administration of appropriate and effective antibiotic therapy. Diagnostic assays capable of quickly and accurately determining the pathogen resistance profile are therefore crucial to initiate or modify care. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a standard method for species identification in many clinical microbiology laboratories and is well positioned to be applied towards antimicrobial susceptibility testing. One recently reported approach utilizes semi-quantitative MALDI-TOF MS for growth rate analysis to provide a resistance profile independent of resistance mechanism. This method was previously successfully applied to Gram-negative pathogens and mycobacteria; here, we evaluated this method with the Gram-positive pathogen Staphylococcus aureus. Specifically, we used 35 strains of S. aureus and four antibiotics to optimize and test the assay, resulting in an overall accuracy rate of 95%. Application of the optimized assay also successfully determined susceptibility from mock blood cultures, allowing both species identification and resistance determination for all four antibiotics within 3 hours of blood culture positivity.

PMID:
28859120
PMCID:
PMC5578647
DOI:
10.1371/journal.pone.0183899
[Indexed for MEDLINE]
Free PMC Article

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