Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolytica

Abstract Background Extensive drug resistance (XDR) is an emerging concern with Mannheimia haemolytica, and a variety of testing methods are available for characterizing in vitro antimicrobial susceptibility. Objectives To compare the concordance among disk diffusion, broth microdilution, and whole...

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Main Authors: Emily R. Snyder, Bridget J. Savitske, Brent C. Credille
Format: Article
Language:English
Published: Wiley 2020-09-01
Series:Journal of Veterinary Internal Medicine
Subjects:
Online Access:https://doi.org/10.1111/jvim.15883
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author Emily R. Snyder
Bridget J. Savitske
Brent C. Credille
author_facet Emily R. Snyder
Bridget J. Savitske
Brent C. Credille
author_sort Emily R. Snyder
collection DOAJ
description Abstract Background Extensive drug resistance (XDR) is an emerging concern with Mannheimia haemolytica, and a variety of testing methods are available for characterizing in vitro antimicrobial susceptibility. Objectives To compare the concordance among disk diffusion, broth microdilution, and whole genome sequencing (WGS) for susceptibility testing of M. haemolytica before and after mass treatment using tulathromycin. Animals Forty‐eight M. haemolytica isolates collected from high‐risk beef stocker calves before and after mass treatment (metaphylaxis) using tulathromycin (Draxxin, Zoetis, Parsippany, NJ) given at the label dosage of 2.5 mg/kg body weight SC in the neck. Methods In vitro antimicrobial susceptibility was determined for all 48 isolates using disk diffusion, broth microdilution, and WGS. Concordance was calculated between pairs of susceptibility testing methods as follows: number of isolates classified identically by the 2 testing methods for each timepoint, divided by the number of isolates tested at that timepoint. Discordance was calculated as follows: number of isolates classified differently by the 2 testing methods for each timepoint, divided by the number of isolates tested at that timepoint. Results Concordance between testing methods ranged from 42.3% to 100%, depending on antimicrobial evaluated, timing of sample collection, and testing method used. Very major errors were identified in up to 7.7% of classifications whereas minor errors were seen in up to 50% of classifications depending on antimicrobial evaluated, timing of sample collection, and testing method used. Conclusions and Clinical Importance Our results show that discrepancies in the results of different susceptibility testing methods occur and suggest a need for greater harmonization of susceptibility testing methods.
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spelling doaj.art-575305427f4a4780b35b92b0329140dd2022-12-21T19:22:20ZengWileyJournal of Veterinary Internal Medicine0891-66401939-16762020-09-013452158216810.1111/jvim.15883Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolyticaEmily R. Snyder0Bridget J. Savitske1Brent C. Credille2Food Animal Health and Management Program, Department of Population Health, College of Veterinary Medicine University of Georgia Athens Georgia USAFood Animal Health and Management Program, Department of Population Health, College of Veterinary Medicine University of Georgia Athens Georgia USAFood Animal Health and Management Program, Department of Population Health, College of Veterinary Medicine University of Georgia Athens Georgia USAAbstract Background Extensive drug resistance (XDR) is an emerging concern with Mannheimia haemolytica, and a variety of testing methods are available for characterizing in vitro antimicrobial susceptibility. Objectives To compare the concordance among disk diffusion, broth microdilution, and whole genome sequencing (WGS) for susceptibility testing of M. haemolytica before and after mass treatment using tulathromycin. Animals Forty‐eight M. haemolytica isolates collected from high‐risk beef stocker calves before and after mass treatment (metaphylaxis) using tulathromycin (Draxxin, Zoetis, Parsippany, NJ) given at the label dosage of 2.5 mg/kg body weight SC in the neck. Methods In vitro antimicrobial susceptibility was determined for all 48 isolates using disk diffusion, broth microdilution, and WGS. Concordance was calculated between pairs of susceptibility testing methods as follows: number of isolates classified identically by the 2 testing methods for each timepoint, divided by the number of isolates tested at that timepoint. Discordance was calculated as follows: number of isolates classified differently by the 2 testing methods for each timepoint, divided by the number of isolates tested at that timepoint. Results Concordance between testing methods ranged from 42.3% to 100%, depending on antimicrobial evaluated, timing of sample collection, and testing method used. Very major errors were identified in up to 7.7% of classifications whereas minor errors were seen in up to 50% of classifications depending on antimicrobial evaluated, timing of sample collection, and testing method used. Conclusions and Clinical Importance Our results show that discrepancies in the results of different susceptibility testing methods occur and suggest a need for greater harmonization of susceptibility testing methods.https://doi.org/10.1111/jvim.15883antimicrobial resistanceantimicrobial stewardshipbovine respiratory diseasegenomics
spellingShingle Emily R. Snyder
Bridget J. Savitske
Brent C. Credille
Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolytica
Journal of Veterinary Internal Medicine
antimicrobial resistance
antimicrobial stewardship
bovine respiratory disease
genomics
title Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolytica
title_full Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolytica
title_fullStr Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolytica
title_full_unstemmed Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolytica
title_short Concordance of disk diffusion, broth microdilution, and whole‐genome sequencing for determination of in vitro antimicrobial susceptibility of Mannheimia haemolytica
title_sort concordance of disk diffusion broth microdilution and whole genome sequencing for determination of in vitro antimicrobial susceptibility of mannheimia haemolytica
topic antimicrobial resistance
antimicrobial stewardship
bovine respiratory disease
genomics
url https://doi.org/10.1111/jvim.15883
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