Epidemiological Cutoff Values for Standard Broth Microdilution and Disk Diffusion Susceptibility Testing of Isolated from Fish

Authors

Charles M. Gieseker, Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA.
Patricia S. Gaunt, Thad Cochran National Warmwater Aquaculture Center, College of Veterinary Medicine, Mississippi State University, Stoneville, Mississippi, USA.
John P. Hawke, Department of Pathobiological Science, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA.
Tina C. Crosby, Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA.
Nicholas R. Hasbrouck, Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA.
Dana X. Gao, Thad Cochran National Warmwater Aquaculture Center, College of Veterinary Medicine, Mississippi State University, Stoneville, Mississippi, USA.
Cynthia B. Stine, Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA.
Eric R. Evans, Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA.
Christopher J. Grim, Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Applied Research and Safety Assessment, Laurel, Maryland, USA.

Document Type

Article

Publication Date

8-1-2022

Abstract

and other closely related species cause motile aeromonad septicemia, a common fish disease. The disease affects many aquaculture sectors potentially requiring antimicrobial treatments. Therefore, researchers and laboratory diagnosticians need criteria called epidemiological cutoff values (ECVs) to determine whether a bacterial isolate has developed decreased susceptibility to an antimicrobial. To generate ECVs for this bacterium, we assembled a diverse collection of 245 isolates previously identified as from fish. Using sequencing, we confirmed that 97 of the 245 isolates were . We allocated the isolates among three laboratories and tested their susceptibility against eight antimicrobials using standard Clinical and Laboratory Standards Institute (CLSI) disk diffusion and broth microdilution methods. The resulting frequency distributions were statistically analyzed to determine wild-type cutoff estimates, which, along with scatterplots, were used to estimate potential ECVs. In collaboration with the CLSI, aquaculture working group, we proposed ECVs for six of the eight antimicrobials tested. Subsequently, the CLSI Subcommittee on Veterinary Antimicrobial Susceptibility Testing reviewed our data and approved the ECVs to be added to the 2020 edition of the VET04 performance standards for antimicrobial susceptibility testing of aquatic bacteria.

Publication Source (Journal or Book title)

Microbial drug resistance (Larchmont, N.Y.)

First Page

893

Last Page

903

Recommended Citation

Gieseker, C. M., Gaunt, P. S., Hawke, J. P., Crosby, T. C., Hasbrouck, N. R., Gao, D. X., Stine, C. B., Evans, E. R., & Grim, C. J. (2022). Epidemiological Cutoff Values for Standard Broth Microdilution and Disk Diffusion Susceptibility Testing of Isolated from Fish. Microbial drug resistance (Larchmont, N.Y.), 28 (8), 893-903. https://doi.org/10.1089/mdr.2021.0316