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Charles M. Gieseker MS, PhD.

Charles M. Gieseker, MS, PhD
Charles M. Gieseker MS, PhD.

Division of Applied Veterinary Research


Charlie obtained his undergraduate degree in fisheries and wildlife management in 1995, then worked as a fisheries biologist for the Maryland Department of Natural Resources (MDDNR) conducting oyster disease research and fish and marine mammal health investigations from 1995 to 2001. While at MDDNR, he also completed a master’s degree from the University of Maryland Baltimore County in collaboration with the National Aquarium in Baltimore focused on the management of aquatic animals in aquariums. In 2001, he joined the US FDA‘s Center for Veterinary Medicine as a biologist conducting aquaculture research. He earned a doctoral degree in marine-estuarine-environmental sciences with a specialization in fisheries science from the University of Maryland in 2015.


Charlie’s research focuses on standardizing antimicrobial susceptibility testing methods for aquatic bacterial pathogens to improve monitoring for antimicrobial resistance and to foster more judicious use of antimicrobials by the aquaculture industry. Part of the work involves using the standardized tests to study the antimicrobial susceptibility profiles of bacteria isolated from farmed fish. In addition, his lab develops fish disease models to study how differences in antimicrobial susceptibility affect the treatment of bacterial fish diseases and to study drug effectiveness in regards to drug approval reviews.

Other research includes studies on chemical/drug pharmacokinetics in edible tissues and organs from farmed fish species. He also collaborates with FDA chemists on developing regulatory methods to detect drug/chemical residues in farmed seafood. His laboratory administers drug or chemical treatments to fish in order to generate tissues that FDA chemists need to verify and validate their detection methods.

Select Publications

Turnipseed, S. B., Storey, J. M., Wu, I-L., Gieseker, C. M., Hasbrouck, N. R., Crosby, T. C., Andersen, W. C., Lanier, S., Casey, C. R., Burger, R., Madson, M. R. 2018. Application and evaluation of a high-resolution mass spectrometry screening method for veterinary drug residues in incurred fish and imported aquaculture samples. Analytical and Bioanalytical Chemistry 410:5529-5544.

Gieseker, C. M., Crosby, T. C., Woods, L. C. 2017. Provisional epidemiological cutoff values for standard broth microdilution susceptibility testing of Flavobacterium columnare. Journal of Fish Diseases. 40:679–686.

Gieseker, C. M., Crosby, T. C., Mayer, T. D., Bodeis, S. M., and Stine, C. B. 2016. Development of similar broth microdilution methods to determine the antimicrobial susceptibility of Flavobacterium columnare and F. psychrophilum. Journal of Aquatic Animal Health. 28:27–38.

Stine, C. B., Nochetto, C. B., Gieseker, C. M., Evans, E. R., Hasbrouck, N. R., Mayer, T. D., Girard, L., Reimschuessel, R. 2013. Depletion of melamine and cyanuric acid in kidney of catfish Ictalurus punctatus and trout Oncorhynchus mykiss. Journal of Veterinary Pharmacology and Therapeutics. 36(6):617–620.

Gieseker, C. M., Mayer, T. D., Crosby, T. C., Carson, J., Dalsgaard, I., Darwish, A. M., Gaunt, P. S., Gao, D. X., Hsu, H-M., Lin, T. L., Oaks, J. L. , Pyecroft, M., Teitzel, C., Somsiri, T. and Wu, C. C. 2012. Quality control ranges for testing broth microdilution susceptibility of Flavobacterium columnare and F. psychrophilum to nine antimicrobials. Diseases of Aquatic Organisms. 101:207–215.

Shaikh, B., Rummel, N., Gieseker, C., Cheely, C-S., Reimschuessel, R. 2012. Residue depletion of tritium-labeled ivermectin in the muscle tissues of aquacultured Atlantic salmon, tilapia, and catfish following oral treatment. North American Journal of Aquaculture. 74:27–33.

Stine, C. B., Reimschuessel, R., Gieseker, C. M., Evans, E. R., Mayer, T. D., Hasbrouck, N. R., Tall, E., Boehmer, J., Gamboa da Costa, G., Ward, J. L. 2011. A no observable adverse effects level (NOAEL) for pigs fed melamine and cyanuric acid. Regulatory Toxicology and Pharmacology. 60:363–372.

Reimschuessel R., Gieseker, C., Poynton, S. 2011. In vitro effect of seven antiparasitics on Acolpenteron ureteroecetes (Dactylogyridae) from largemouth bass, Micropterus salmoides (Centrarchidae). Diseases of Aquatic Organisms. 94:59–72.

Contact Information
Charles M. Gieseker
+1 (240)-402-5402
+1 (301)-210-4685
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