E. Fidelma Boyd, Ph.D.


BISC 682 Molecular Mechanisms of Pathogens
BISC 850 Advanced Topics in Microbiology

Research Interests

Vibrio parahaemolyticus a halophile with diverse traits and disease pathology
Vibrio parahaemolyticus is a halophile and salt is an absolute requirement for growth. Vibrio parahaemolyticus is the leading cause of bacterial seafood borne gastroenteritis worldwide and is an important pathogen of fish and shellfish.   

In our group, we investigate the following

The role of quorum sensing regulators in the osmotic stress tolerance response  

Bacterial factors required for host colonization

How bacterial metabolism influences bacterial host interactions

Vibrio cholerae, the causative agent of the dreaded diarrheal disease cholera   

For cholera infection, two virulence factors are indispensable; cholera toxin and the toxin corregulated pilus, and both are contained on mobile and integrative genetic elements (MIGEs). Our group identified a pathogenicity island named Vibrio Pathogenicity Isalnd-2, which encodes the genes required for sialic acid scavenging, uptake and catabolism and showed that these genes were important for host colonization.  

In our group, we examine the following;

How pathogenicity islands integrate and excise from the bacterial chromosome

The evolution of pathogenicity islands among bacteria

The role of island cargo genes in the physiology of the bacterium

Vibrio vulnificus a marine bacterium and opportunistic pathogen of humans

Vibrio vulnificus is one of the most deadly bacterial pathogens known with a mortality rate of nearly 70% in susceptible individuals. In this species, we study the synthesis of the amino sugar nonulosonic acid, a sialic acid-like molecule present in bacteria. V. vulnificus produces at least two types legionaminic acid and pseudaminic acid 

In our group, we explore the following

Sialylation of the bacterial cell wall

How sialylation influences cell physiology

Bacterial metabolism impact on host competitiveness


Research Group

Gwendolyn Gregory, -Ph.D/M.B.A. Graduate student program, (B.S.), Osmotic tolerance regulation

Kent Kwah, -Ph.D./M.B.A. Graduate student program, (B.S. Montana State University), Regulation of filamentous phage by the transcription factor OpaR.

Jessica Tague, -Ph.D/M.B.A. Graduate student program, (B.S. Salisbury University), Role of sigma factor RpoN in the quorum sensing pathway.

Abish RegmiPh.D./M.B.A. Graduate student (B.S. Towson State University). Vibrio parahaemolyticus carbohydrate utilization and metabolic fitness.

John Rosenberger, M.S. Graduate student (B.S. University of Delaware). Characterization of bacterial sialic acid like molecules.

Daniel Morreale, Undergraduate Researcher, University of Delaware

Selected Publications

Regmi, A. and E.F. Boyd. 2019. Carbohydrate metabolism systems present on genomic islands that are lost and gained in Vibrio parahaemolyticus. BMC Microbiology, In Revision.

McDonald, N.D*, Regmi, A.*, J.D. Borowski, D.P. Morreale, and Boyd, E.F. 2019. CRISPR-Cas systems are carried on mobile genetic elements in Vibrio species. BMC Genomics, 2019 Feb 4;20(1):105. *co-first authors.

Mc Donald, N.D., K. Demeester, A.L. Lewis, C. L. Grimes, and E.F. Boyd. 2018. Structural and functional characterization of a modified legionaminic acid involved in glycosylation of the bacterial lipopolysaccharide. Journal Biological Chemistry, 2018 Dec 7;293(49):19113-19126.

Richards, G.P., M. A. Watson, D. S. Needleman, J. Uknalis, E. F. Boyd, and J. P. Fay. 2017. Mechanisms for Pseudoalteromonas piscicida-induced killing of Vibrios and other bacterial pathogens. Applied and Environmental Microbiology, AEM.00175-17.

Carpenter, M.R., Kalburge, S.S., Borowski, M.R. Peters, R.R. Colwell, and E.F. Boyd. 2017. CRISPR-Cas and contact dependent secretion systems on excisable pathogencity islands with conserved recombination modules. J. Bacteriology, JB.00842-16.

Kalburge, S.S., Carpenter, M.R., Rozovsky, S., and E.F. Boyd. 2017. Quorum sensing regulators required for metabolic fitness in Vibrio parahaemolyticus. Infection and Immunity, 23;85(3).

McDonald, N.D., J.B. Lubin, N.Chowdhury, and E.F. Boyd.  2016. Host-derived sailic acids are an important nutrient source required for opitimal bacterial fitness in vivo. MBio. 2016 Apr 12;7(2):e02237-15.

Carpenter, M.R., Rozovsky, S., and E.F. Boyd. 2016. Pathogenicity island cross-talk mediated by recombination directionality factors can facilitate excision and spread of virulence genes in bacteria. J. Bacteriol. 14;198(5):766-76   

Lubin, J.B., W.G. Lewis, N.M Gilbert, S. Almagro-Moreno, E.F. Boyd, and A.L. Lewis. 2015. Host-like carbohydrates promote bloodstream survival of Vibrio vulnificus in vivo. Infection and Immunity. 10.1128/IAI.00345-15.

Boyd, E.F., M.R. Carpenter, N. Chowdhury, A.L. Cohen, B.L. Haines-Menges, J.J. Kingston, S. S. Kalburge, J.B. Lubin, S.Y. Ongagna-Yhombi, and W.B. Whitaker. 2015. Postgenomic analysis of the evolutionary history of Vibrio.  Microbiology Spectrum, 3(5).

Ongagna-Yhombi, S.Y., N.D. McDonald, and E.F. Boyd. 2015. Deciphering the role of multiple betaine choline carnitine transporters in the halophile Vibrio parahaemolyticus. Applied and Environmental Microbiology, 81(1):351-63.

Haines-Menges, B.L., Whitaker, W.B., J.B. Lubin, and E.F. Boyd. 2015. Host Sialic Acids: A delicacy for the pathogen with discerning taste. In Metabolism and Bacterial Virulence. Edited T. Conway and P. Cohen, ASM Press. Microbiology Spectrum, 3(4).

Haines-Menges, B.L., Whitaker, W.B., and E.F. Boyd. 2014. The alternative sigma factor RpoE is essential for Vibrio parahaemolyticus cell envelope stress response and intestinal colonization. Infection and Immunity, 82:3667-77.


Interim Chair

Phone: (302) 831-1088

Fax: (302) 831-2281

Email: fboyd@udel.edu

Office: 328 Wolf Hall

Lab: 353 Wolf Hall

Department of Biological Sciences
Wolf Hall
University of Delaware
Newark, DE 19716


  • B.S. -National University of Ireland (Galway, Ireland)
  • Ph.D. - National University of Ireland (Galway, Ireland)
  • Postdoctoral - The Pennsylvania State University
  • Postdoctoral - Harvard University
  • Postdoctoral - Tufts University School of Medicine