Marilyn C. Roberts, PhD

Professor, Env. and Occ. Health Sciences (Primary department)
Adjunct Professor, Global Health
Adjunct Professor, Pediatric Dentistry
Dr. Roberts' research interests include identification of methicillin resistant Staphylococcus aureus [MRSA] and vancomycin resistant enterococci [VRE] in environmental samples, antibiotic resistance using a One Health approach. Dr. Roberts is interested in how antibiotic resistance genes and resistant bacteria move between the environment, humans and animals. Also, the mechanisms of resistance, how resistance spreads through bacterial populations in man, animals and the environment and ultimately, how these genes affect therapy. She is now isolating and characterizing MRSA from primates, personnel and the environment from the Washington National Primate Research Center. Future work is to look for MRSA in primate populations outside North America both in Primate centers and wild populations. The laboratory is also interested in antibiotic resistance in oral and urogenital bacteria in general. She is using whole genome sequencing to compare isolates taken from humans, animals and their shared environment. 

Contact Information

University of Washington
Office: F-161D
Box: 357234
1959 NE Pacific St
Seattle, WA 98195-
Tel: 206-543-8001
Tel: 206-543-6418

Research Interests

  • Environmental vancomycin resistant enterococci [VRE]. Environmental, clinical and occupational methicillin resistant Staphylococcus aureus [MRSA]. Antibiotic & mercury resistance genes in the environment. Bacterial genetics and gene exchange and comparing genomes using whole genome sequencing. Emerging and reemerging diseases. Molecular epidemiology. One Health and how the environment, humans and animals interact and share antibiotic resistant bacteria. Antibiotic resistance genes and diseases with work with birds, cows, primates, orca whales and river otters.

In the News

Teaching interests

Molecular epidemiology, infectious diseases, antibiotic resistance and public health, environmental microbiology laboratory sampling, One Health and antibiotic resitant bacteria/genes and their impact on the environment and Public Health


PhD, Microbiology, University of Washington, 1978
MS, Microbiology, University of Washington, 1977


MRSA contamination throughout the Washington National Primate Research Center including people, primates and their shared environment.
MRSA contamination in other occupational environments
MRSA carriage in fire fighters and other occupations
Zoonotic pathogens in wild birds and their environment
Macrolide and tetracycline resistance genes in the environment
MRSA in wild primate populations around the world
Selected Publications
Roberts, M.C., P.R. Joshi, A.L. Greninger, D. Melendez, S. Paudel, M. Acharya, N.K. Bimali, N.P. Koju, D. No, M. Chalise and R.C. Kyes. The human clone ST22 SCCmec IV methicillin-resistant Staphylococcus aureus isolated from swine herds and wild primates in Nepal: Is man the common source?  FEMS Microbiol Eco. 94:  2018.
Michael, K.E., D. No, and M.C. Roberts. vanA positive multidrug-resistant Enterococcus spp. isolated from surfaces of a US hospital facility.  J Hosp. Infect. 95:218-223, 2017.
Michael, K.E., D. No, W.E. Daniell, N.S. Seixas, and M.C. Roberts.  Assessment of environmental contamination with pathogenic bacteria at a university laundry facility.  Annals of Work Exp and Health. 61:1087-1096, 2017.
Soge, OO, D. No, K. Michael, J. Dankoff, J. Lane, K. Vogel, J. Smedley, and M.C. Roberts. Transmission of MDR MRSA between primates personnel and environment at a United States primate center. J. Antimicrob. Chemother. 71:2798-2803, 2016. 
Michael, K., D. No, J. Dankoff, K. Lee, E. Lara-Crawford, and M.C. Roberts.  Clostridium difficile environmental contamination within a clinical laundry facility in the USA.  FEMS Microbiol. Lett. 363:1-5, 2016. 
Michael, K.E., D. No, and M.C. Roberts. Methicillin-resistant Staphylococcus aureus (MRSA) isolates from surfaces and personnel at a hospital laundry facility. J. Appl Microbiol. 121:846-854, 2016. 
Roberts, M.C., D.B. No, J.M. Marzluff, J.H. DeLap, and R. Turner. Vancomycin resistant Enterococcus spp. from crows and their environment in Metropolitan Washington State, USA: Is there a correlation between VRE positive crows and the environment? Vet Microbiol. 194:48-54, 2016. 
Lin, J., Nishino, K., M.C. Roberts, M. Tolmasky, R. Aminov, and L. Zhang. Mechanisms of antibiotic resistance. 2015. Frontier in Microbiol: Antimicrobials Resistance & Chemotherapy. 6:34. doi:10.3389/fmicb.2015.00034
Roberts, M.C., D. No, E. Kuchmiy, and C. D. Miranda. The tetracycline resistant tet(39) gene identified in three new genera of bacteria isolated in 1999 from Chilean Salmon farms. J. Antimicrob. Chemother. 70:619-620, 2015.
Roberts, M.C. and D. No Environmental surface sampling in 33 Washington State fire stations for methicillin-resistant and methicillin-susceptible Staphylococcus aureus. Am. J. Infect. Control. 42:591-596, 2014. 
Roberts, M.C., O.O. Soge, and D.B. No. Comparison of multi-drug resistant environmental methicillin-resistant Staphylococcus aureus [MRSA] isolated from recreational beaches and high touch surfaces in built environments. Frontier in Microbiol: Antimicrobials Resistance & Chemotherapy. 4:74; 1-8, 2013. 
Clarridge, J.E., III, A.T. Harrington, M.C. Roberts, O.O. Soge, and K. Maquelin. Impact of strain typing method on assessing the relationship of paired nares and wound isolates of methicillin-resistant Staphylococcus aureus. J. Clin. Microbiol. 51:224-231, 2013
Roberts, M.C., S. Schwarz, H. Aarts. Acquired antibiotic resistance genes: an overview. Frontier in Microbiol: Antimicrobials Resistance & Chemotherapy 2012 doi: 10.3389/fmicb.2012.00384; 3:384; 1-17, 2012.
Levin-Edens, E., O.O. Soge, D.B. No, A. Stiffarm, J.S. Meschke and M.C. Roberts. Methicillin-resistant Staphylococcus aureus from Northwest marine and fresh water recreational beaches. FEMS Microbiol Ecol. 79:412-420, 2012.
Roberts, M.C. Environmental macrolide-lincosamide-streptogramin and tetracycline resistant bacteria. Frontier: Antimicrob Resist. Chemoth, 2011. doi: 10.3389/fmicb.2011.00040;,_resistance_and_chemotherapy/10.3389/fmicb.2011.00040/abstract 
Roberts, M.C., O.O. Soge, D.B. No, N. Beck, and J.S. Meschke. Isolation and characterization of methicillin-resistant Staphylococcus aureus (MRSA) from fire stations in two Northwest fire districts. Am. J. Infect. Control. 39:382-389, 2011.
Roberts, M.C., O.O. Soge, D.B. No, S.E. Helgeson, and J.S. Meschke. Characterization of methicillin-resistant Staphylococcus aureus isolated from public surfaces on a University campus, student homes and local community. J. Appl. Microbiol. 110:1531-1537.
Levin-Edens, E., J.S. Meschke and M.C. Roberts. Quantification of methicillin-resistant Staphylococcus aureus strains in marine and fresh water samples by most-probable-number. Appl. Environ. Microbiol. 77:3541-3543, 2011.
Levin-Edens, E., N. Bonilla, J.S. Meschke and M.C. Roberts. Survival of environmental and clinical strains of methicillin-resistant Staphylococcus aureus [MRSA] in Pacific Northwest and fresh waters. Water Res. 45:5681-5686, 2011.
Roberts, M.C., O.O. Soge, J.A. Horst, K.A. Ly and P. Milgrom. MRSA from dental school surfaces and students. Am. J. Infect. Control. 39:628-632, 2011.
Soge, O.O., M.A. Giardino, I. Ivanova, A.L. Pearson, J.S. Meschke, and M.C. Roberts. Low prevalence of antibiotic resistant Gram-negative bacteria from rural Southwestern Ugandan groundwater. Water SA. 35:343-347, 2009.
Roberts, M.C., O.O. Soge, M.A. Giardino, E. Mazengia, G. Ma, and J.S. Meschke. Vancomycin Resistant Enterococcus spp. in Marine Environments from the West Coast of the USA. J. App. Microbiol. 107:300-307, 2009.
Soge, O.O., J.S. Meschke, D.B. No, and M.C. Roberts. Characterization of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin-Resistant Coagulase-Negative Staphylococcus spp. (MRCoNS) Isolated from West Coast Public Marine Beaches. J. Antimicrob. Chemother. 64: 1148-1155, 2009.
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