• Melanie J. Abley, Thomas E. Wittum, Julie A. Funk, and Wondwossen A. Gebreyes. Antimicrobial Susceptibility, Pulsed-Field Gel Electrophoresis, and Multi-locus Sequence Typing of Campylobacter coli in Swine Before, During, and After the Slaughter Process. FOODBORNE PATHOGENS AND DISEASE. Volume 9, Number 6, 2012.
  • Brooke K. Decker, Federico Perez., Andrea M. Hujer, Kristine M. Hujer, Geraldine S. Hall, Michael R. Jacobs, Wondwossen A. Gebreyes, Scott T. Zoll, Christian Massire, Mark W. Eshoo, David J. Ecker, Philip N. Rather, Robert A. Bonomo (2012). Longitudinal Analysis of the Temporal Evolution of Acinetobacter baumannii Strains in Ohio, USA, by Using Rapid Automated Typing Methods. PLoS ONE 7(4): e33443. doi:10.1371/journal.pone.0033443.
  • Pamela R. Fry, Siddhartha Thakur, Melanie Abley and Wondwossen A. Gebreyes. Antimicrobial Resistance, Toxinotype, and Genotypic Profiling of Clostridium difficile Isolates of Swine Origin. J. Clin. Microbiol. 2012, 50(7):2366.
  • Bayleyegn Molla, Megan Byrne, Melanie Abley, Jennifer Mathews, Charlene R. Jackson, Paula Fedorka-Cray, Srinand Sreevatsan, Ping Wang, Wondwossen A. Gebreyes. Epidemiology and Genotypic Characteristics of Methicillin-resistant Staphylococcus aureus (MRSA) of porcine origin. J. Clin. Microbiol. 2012.
  • Dixie F. Mollenkopf, Matthew F. Weeman, Joshua B Daniels, Melanie J. Abley, Jennifer L. Mathews, Wondwossen A. Gebreyes and Thomas E. Wittum. Variable within- and between-Herd Diversity of CTX-M Cephalosporinase-Bearing Escherichia coli Isolates from Dairy Cattle. Appl. Environ. Microbiol. 2012, 78(13):4552.
  • N. P. A. Rodrigues, P. E. N. Givisiez , R. C. R. E. Queiroga , P. S. Azevedo , W. A. Gebreyes and C. J. B. Oliveira. Milk adulteration: Detection of bovine milk in bulk goat milk produced by smallholders in northeastern Brazil by a duplex PCR assay. 2012. J. Dairy Sci. 95 :2749–2752



  • Lutz EA, McCarty MJ, Mollenkopf DF, Funk JA, Gebreyes WA, Wittum TE. Ceftiofur Use in Finishing Swine Barns and the Recovery of Fecal Escherichia coli or Salmonella spp. Resistant to Ceftriaxone.Foodborne Pathog Dis. 2011 Aug 5. View Article 
  • Wang Q, Scheuer K, Ahang Z, Gebreyes WA, Molla BZ, Hoet AE, Saif LJ. Characterization and prevalence of a new porcine Calicivirus in Swine, United States. Emerg Infect Dis. 2011 Jun;17(6):1103-6. View Article
  • Oliveira CJ, Lopes Júnior WD, Queiroga RC, Givisiez PE, Azevedo PS, Pereira WE, Gebreyes WA. Risk factors associated with selected indicators of milk quality in semiarid northeastern Brazil. J Dairy Sci. 2011 Jun;94(6):3166-75. View Article
  •  Hoet AE, Johnson A, Nava-Hoet RC, Bateman S, Hillier A, Dyce J, Gebreyes WA, Wittum TE. Environmental methicillin-resistant Staphylococcus aureus in a veterinary teaching hospital during a nonoutbreak period. Vector Borne Zoonotic Dis. 2011 Jun;11(6):609-15. View Article 
  • Bharathi Srinivasan V, Rajamohan G, Pancholi P, Marcon M, Gebreyes WA. Molecular cloning and functional characterization of two novel membrane fusion proteins in conferring antimicrobial resistance in Acinetobacter baumannii. J Antimicrob Chemother. 2011 Mar;66(3):499-504.
  • Tadesse DA, Bahnson PB, Funk JA, Thakur S, Morrow WE, Wittum T, Degraves F, Rajala-Schultz P, Gebreyes WA Prevalence and Antimicrobial Resistance Profile of Campylobacter Spp. Isolated from Conventional and Antimicrobial-Free Swine Production Systems from Different U.S. Regions. Foodborne Pathog Dis. 2011 Mar;8(3):367-74. View Article
  • Mollenkopf DF, Kleinhenz KE, Funk JA, Gebreyes WA, Wittum TE. Salmonella enterica and Escherichia coli Harboring bla(CMY) in Retail Beef and Pork Products. Foodborne Pathog Dis. 2011 Feb;8(2):333-6. View Article 
  • Sibhat B, Molla Zewde, A. Zerihun, A. Muckle, L. Cole, P. Boerlin, E. Wilkie, A. Perets,K. Mistry and W. A. Gebreyes. Salmonella Serovars and Antimicrobial Resistance Profiles in Beef Cattle, Slaughterhouse Personnel and Slaughterhouse Environment in Ethiopia. Zoonoses Public Health. 58(2011) 102–109.
  • Bing Wang, Chong Wang, James D. McKean, Catherine M. Logue, Wondwossen A. Gebreyes, Kelly A. Tivendale, and Annette M. O’Connor. Salmonella enterica in Swine Production: Assessing the Association between Amplified Fragment Length Polymorphism and Epidemiological Units of Concern. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Nov. 2011, p. 8080–8087.
  • Yasser M. Sanad, Issmat I. Kassem, Melanie Abley, Wondwossen Gebreyes, Jeffrey T. LeJeune, Gireesh Rajashekara. Genotypic and Phenotypic Properties of Cattle-Associated Campylobacter and Their Implications to Public Health in the USA. PLoS ONE 6(10): e25778. doi:10.1371/journal.pone.0025778.
  • Jennifer B. Walker, Päivi J. Rajala-Schultz, William L. Walker, Jennifer L. Mathews, Wondwossen A. Gebreyes and Fred J. DeGraves. Variation in daily shedding patterns of Staphylococcus aureus in naturally occurring intramammary infections. Journal of Veterinary Diagnostic Investigation 23(6) 1114–1122


  • Wittum TE, Mollenkopf DF, Daniels JB, Parkinson AE, Mathews JL, Fry PR, Abley MJ, Gebreyes WA. CTX-M-type extended-spectrum β-lactamases present in Escherichia coli from the feces of cattle in Ohio, United States. Foodborne Pathog Dis. 2010 Dec;7(12):1575-9. View Article 
  • Thakur S, Gebreyes WA. Phenotypic and genotypic heterogeneity of Campylobacter coli within individual pigs at farm and slaughter in the US.Zoonoses Public Health. 2010 Nov;57 Suppl 1:100-6. View Article
  • Sopirala MM, Mangino JE, Gebreyes WA, Biller B, Bannerman T, Balada-Llasat JM, Pancholi P. Synergy testing by Etest, microdilution checkerboard, and time-kill methods for pan-drug-resistant Acinetobacter baumannii. Antimicrob Agents Chemother. 2010 Nov;54(11):4678-83. View Article
  • Molla B, Sterman A, Mathews J, Artuso-Ponte V, Abley M, Farmer W, Rajala-Schultz P, Morrow WE, Gebreyes WA. Salmonella enterica in commercial swine feed and subsequent isolation of phenotypically and genotypically related strains from fecal samples. Appl Environ Microbiol. 2010 Nov;76(21):7188-93. View Article 
  • Thakur S, Putnam M, Fry PR, Abley M, Gebreyes WA.  Prevalence of antimicrobial resistance and association with toxin genes in Clostridium difficile in commercial swine.  Am J Vet Res. 2010 Oct;71(10):1189-94. View Article 
  • Alali WQ, Thakur S, Berghaus RD, Martin MP, Gebreyes WA. Prevalence and Distribution of Salmonella in Organic and Conventional Broiler Poultry Farms. Foodbourne Pathog Dis. 2010 Nov;7(11):1363-71 . View Article
  • Thakur S, Zhao S, McDermott PF, Harbottle H, Abbott J, English L, Gebreyes WA, White DG. Antimicrobial resistance, virulence, and genotypic profile comparison of Campylobacter jejuni and Campylobacter coli isolated from humans and retail meats. Foodbourne Pathog Dis. 2010 Jul;7(7):835-44. View Article
  • Rajamohan G, Srinivasan VB, Gebreyes WA. Molecular and functional characterization of a novel efflux pump, AmvA, mediating antimicrobial and disinfectant resistance in Acinetobacter baumannii. J Antimicrob Chemother. 2010 June 23. [Epub ahead of print] View Abstract
  • Patchanee P, Molla B, White N, Line DE, Gebreyes WA. Tracking Salmonella Contamination in Various Watersheds and Phenotypic and Genotypic Diversity. Foodbourne Pathog Dis. 2010 June 8. [Epub ahead of print] View Article
  • Drozd M, Kassem II, Gebreyes WA, Rajashekara G. A quantitative polymerase chain reaction assay for detection and quantification of Lawsonia intracellularis. J Vet Diagn Invest. 2010 Mar;22(2):265-9. View Article
  • Rajamohan G, Srinivasan VB, Gebreyes WA. Novel role of Acinetobacter baumannii RND efflux transporters in mediating decreased susceptibility to biocides. J Antimicrob Chemother. 2010 Feb;65(2):228-32. View Abstract
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  • Srinivasan VB, Rajamohan G, Gebreyes WA. The role of a novel efflux pump AbeS, member of the SMR family of transporters in resistance to antimicrobial agents in Acinetobacter baumannii. Antimicrob Agents Chemother. 2009 Sep 21. [Epub ahead of print] View Article
  • Rajamohan G, Srinivasan VB, Gebreyes WA. Biocide-tolerant multidrug-resistant Acinetobacter baumannii clinical strains are associated with higher biofilm formation. J Hosp Infect. 2009 Nov;73(3):287-9.
  • Heider LC, Hoet AE, Wittum TE, Khaitsa ML, Love BC, Huston CL, Morley PS, Funk JA, Gebreyes WA. Genetic and Phenotypic Characterization of the bla(CMY) Gene from Escherichia coli and Salmonella enterica Isolated from Food-Producing Animals, Humans, the Environment, and Retail Meat. Foodborne Pathog Dis. 2009 Sep 10. [Epub ahead of print]
  • Schissler J., Hillier A., Daniels J., Cole L. and Gebreyes WA. 2009. Evaluation of Clinical Laboratory Standards Institute interpretive criteria for methicillin-resistant Staphylococcus pseudintermedius isolated from dogs. J Vet Diagn Invest. 2009 Sep;21(5):684-8.
  • Dorr PM, Nemechek MS, Scheidt AB, Baynes RE, Gebreyes WA, Almond GW. Water-flow variation and pharmacoepidemiology of tetracycline hydrochloride administration via drinking water in swine finishing farms. J Am Vet Med Assoc. 2009 Aug 1;235(3):299-304. View Article
  • Alali WQ, Scott HM, Norby B, Gebreyes W, Loneragan GH. Quantification of the bla(CMY-2) in feces from beef feedlot cattle administered three different doses of ceftiofur in a longitudinal controlled field trial. Foodborne Pathog Dis. 2009 Oct;6(8):917-24. View Article
  • Vijaya Bharathi Srinivasan, Govindan Rajamohan, Preeti Pancholi, Kurt Stevenson, Daniel A. Tadesse, Prapas Patchanee, Mario Marcon, Gebreyes WA. 2009. Genetic relatedness and molecular characterization of resistance determinants in multi-drug resistant Acinetobacter baumannii isolated in central Ohio, USA. Annuals of Clinical Microbiology and Antimicrobials 2009 Jun 17;8:21. View Article
  • Pandya M, Wittum T, Tadesse DA, Gebreyes W, Hoet A. 2009. Environmental Salmonella Surveillance in The Ohio State University Veterinary Medical Center. Vector Borne Zoonotic Dis. Mar 9. [Epub ahead of print] View Article
  • Heider LC, Funk JA, Hoet AE, Meiring RW, Gebreyes WA, Wittum TE. 2009. Identification of Escherichia coli and Salmonella enterica organisms with reduced susceptibility to ceftriaxone from fecal samples of cows in dairy herds. Am J Vet Res. (3):389-93. View Article
  • Thakur, Siddhartha; White, David; McDermott, Patrick; Zhao, Shaohua; Harbottle, Heather; Gebreyes WA; Abbott, Jason; English, Linda; Carter, Peggy; Kroft, Brenda; Lafon, Patti. 2009. Genotyping of Campylobacter coli isolated from Humans and Retail Meats Using Multi Locus Sequence Typing and Pulsed Field Gel Electrophoresis. J Applied Microbiol. 106(5): 1722-1733. View Article
  • Zewde BM, Robbins R, Abley MJ, House B, Morrow WE, Gebreyes WA. Comparison of Swiffer wipes and conventional drag swab methods for the recovery of Salmonella in swine production systems. J Food Prot. 2009 Jan;72(1):142-6.
  • Dorr PM, Tadesse DA, Zewde BM, Fry P, Thakur S, Gebreyes WA.Longitudinal Study on Salmonella dispersion and the role of environmental contamination in commercial swine production systems. Appl Environ Microbiol. 2009 Jan 9. View Article
  • Gebreyes WA, Thakur S, Dorr P, Tadesse DA, Post K, Wolf L. Occurrence of spvA virulence gene and clinical significance for multidrug-resistant Salmonella strains. J Clin Microbiol. 2009 Mar;47(3):777-80. View Article;
  • Rajala-Schultz PJ, Torres AH, Degraves FJ, Gebreyes WA, Patchanee P. Antimicrobial resistance and genotypic characterization of coagulase-negative staphylococci over the dry period. Vet Microbiol. 2009 Feb 16;134(1-2):55-64. View Article
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  • Paul M. Dorr and Gebreyes WA. 2008. Flavophospholipol: Effect on multi-drug resistant Salmonella enterica serovar Typhimurium in swine. J Swine Health and Production (In Review).
  • Daniel A. Tadesse, Peter B. Bahnson, Julie A. Funk, Siddhartha Thakur, W.E. Morgan Morrow, Melanie Abley and Gebreyes WA. 2008. Yersinia enterocolitica of porcine origin, carriage of virulence genes and genotypic diversity. Foodborne Pathogens and Diseases (In Review)
  • Gebreyes WA, Bahnson P., Funk JA, McKean J., Patchanee P. Seroprevalence of Trichinella, Toxoplasma and Salmonella in Antimicrobial-free and Conventional Swine Production Systems. Foodborne Pathogens and Diseases. 2008; 5(2):199-203. View Article
  • Heider, L.C., Meiring, R.W., Hoet, A.E., Gebreyes, W.A., Funk, J.A., Wittum, T.E. 2008. The effect of vaccination with a commercial subunit vaccine on the shedding of Salmonella enterica in non-clinically infected dairy cows. JAVMA 233(3):466-469. View Article
  • Patchanee P, Zewde BM, Tadesse DA, Hoet A, Gebreyes WA. Characterization of multidrug-resistant Salmonella enterica serovar Heidelberg isolated from humans and animals. Foodborne Pathog Dis. 2008 Dec;5(6):839-51. View Article
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  • Thakur S, Tadesse DA, Morrow M, Gebreyes WA. Occurrence of multidrug resistant Salmonella in antimicrobial-free (ABF) swine production systems. Vet Microbiol. 2007 Dec 15;125(3-4):362-7. View Article
  • Miller O, Fuller FJ, Gebreyes WA, Lewbart GA, Shchelkunov IS, Shivappa RB, Joiner C, Woolford G, Stone DM, Dixon PF, Raley ME, Levine JF. Phylogenetic analysis of spring virema of carp virus reveals distinct subgroups with common origins for recent isolates in North America and the UK. Dis Aquat Organ. 2007 Jul 16;76(3):193-204. Abstract
  • Siemon CE, Bahnson PB, Gebreyes WA. Comparative investigation of prevalence and antimicrobial resistance of Salmonella between pasture and conventionally reared poultry. Avian Dis. 2007 Mar;51(1):112-7. Abstract
  • Dorr PM, Gebreyes WA, Almond GW. Porcine reproductive and respiratory syndrome virus: Age and management system disease modeling for pathogenic co-infection. J Swine Health Prod 2007;15(5):258-264. View Article
  • Dorr PM, Baker RB, Almond GW, Wayne SR, Gebreyes WA. 2007. Epidemiologic assessment of porcine circovirus type 2 coinfection with other pathogens in swine. J Am Vet Med Assoc. 230(2):244-50. View Article
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  • Thakur S, Morrow WEM, Funk JA, Bahnson PB, Gebreyes WA. 2006. Molecular Epidemiologic investigation of Campylobacter coli in swine production systems using Multi-Locus Sequence Typing (MLST). Applied Environ Microbiol 72(8):5666-9. View Article
  • Gebreyes WA, S. Thakur and W.E. Morrow. 2006. Comparison of Prevalence, Antimicrobial Resistance and Occurrence of Multi-drug resistant Salmonella in Antimicrobial-free and Conventional Pig Production Systems. Journal of Food Protection. 69(4): 743-748. Abstract
  • Gebreyes, W.A., Altier, C. and Thakur, S. 2006. Molecular Epidemiology and Diversity of Salmonella serovar Typhimurium in Pigs using Phenotypic and Genotypic Approaches. Epidemiology and Infection. 134: 187-198. Abstract
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  • Thakur S. and W.A. Gebreyes. 2005. Prevalence and Antimicrobial Resistance of Campylobacter in Antimicrobial-Free and Conventional Production Systems. Journal of Food Protection 68(11):2402-10. Abstract
  • S. Thakur and W.A. Gebreyes. 2005. Campylobacter coli in Swine Production: Antimicrobial Resistance Mechanisms and Molecular Epidemiology. J Clin Microbiol. 43(11):5705-14. View Article
  • Gebreyes, WA, S. Thakur and W.E. M. Morrow. 2005. Campylobacter coli: Prevalence and antimicrobial resistance in Antimicrobial-free Swine Production Systems. J. Antimicrob Chemother 56(4):765-8. View Article
  • Gebreyes WA, Thakur S. 2005. Multidrug-resistant Salmonella enterica serovar Muenchen from pigs and humans and potential interserovar transfer of antimicrobial resistance. Antimicrob Agents Chemother. 49(2):503-11. View Article
  • Kong XQ, Shea D, Gebreyes WA, Xia XR. 2005. Novel hydrophobicity ruler approach for determining the octanol/water partition coefficients of very hydrophobic compounds via their polymer/solvent solution distribution coefficients. Anal Chem. 77(5):1275-81. View Article



  • Funk, J.A. and W.A. Gebreyes. 2004. Risk factors associated with Salmonella prevalence on swine farms. J Swine Health Prod.12: 246-51. View Article
  • Gebreyes, W.A., S. Thakur, P. R. Davies, J. A. Funk and C. Altier. 2004. Trends in antimicrobial resistance, phage types and integrons among Salmonella serotypes from pigs, 1997-2000. J. Antimicrob Chemother 53(6):997-1003. View Article
  • Gebreyes, W.A., P. R. Davies, P.-K. Turkson, W.E. M. Morrow , J. A. Funk, C. Altier. 2004. Salmonella enterica serovars from pigs on-farm and after slaughter and validity of using bacteriologic data to define herd Salmonella status. Journal of Food Protection 67(4): 691-697. Abstract
  • Gebreyes, W.A., P. R. Davies, P. K. Turkson, W.E. M. Morrow , J. A. Funk, C. Altier, S. Thakur. 2004. Characterization of antimicrobial resistance phenotypes and genotypes among Salmonella enterica recovered from pigs on-farm, trucks and after slaughter. Journal of Food Protection 67(4): 698-705. Abstract
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  • Gebreyes, W.A. 2003. Preharvest Food safety diagnostics for Salmonella serovars. Part 2: Molecular diagnostics. J Swine Health Prod. 11: 141-145. View Article
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  • Gebreyes, W.A. and C. Altier. 2002. Molecular Characterization of Multidrug-Resistant Salmonella enterica subsp. enterica Serovar Typhimurium Isolates from Swine. J Clin Microbiol 40(8): 2813-2822. View Article
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  • Funk, J.A., P. Davies and W.A. Gebreyes. 2001. Risk factors associated with Salmonella enterica prevalence in three-site swine production systems in North Carolina, USA. Tierarztliche Wochenschrift. 114: 335-338. Abstract
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  • Gebreyes, W.A., J.A. Funk, P. Davies, and C. Altier. 2000. Antimicrobial Resistance of Salmonella Isolates from Swine. J Clin Microbiol 38:4633-4636. View Article