title: Pathogenesis of Streptococcus infantarius subspecies coli Isolated from Sea Otters with Infective Endocarditis.
abstract: The Gram positive bacterial coccus Streptococcus infantarius subspecies coli is increasingly linked with development of fatal vegetative infective endocarditis and septicemia in humans, sea otters (Enhydra lutris) and other animals. However, the pathogenesis of these infections is poorly understood. Using S. infantarius subsp. coli strains isolated from sea otters with infective endocarditis, this study evaluated adherence and invasion of epithelial and endothelial cells, adherence to extracellular matrix components, and macrophage survival. Significant adherence to endothelial-derived cells was observed for 62% of isolates, 24% adhered to epithelial cell lines, and 95% invaded one or both cell types in vitro. The importance of the hyaluronic acid capsule in host cell adherence and invasion was also evaluated. Capsule removal significantly reduced epithelial adherence and invasion for most S. infantarius subsp. coli isolates, suggesting that the capsule facilitates attachment to and invasion of epithelium. Enzyme-linked immunosorbent assay testing revealed that all isolates adhered significantly to the extracellular matrix components collagen IV, fibronectin, laminin and hyaluronic acid. Finally, significant bacterial survival following phagocytosis by macrophages was apparent for 81% of isolates at one or more time points. Taken collectively these findings indicate that S. infantarius subsp. coli has multiple pathogenic properties that may be important to host colonization, invasion and disease.
authors.affiliation: University of California Davis, School of Veterinary Medicine, Department of Pathology, Microbiology and Immunology, 4206 VM3A, One Shields Avenue, Davis, CA 95616, USA. Electronic address: katrinac@alaskasealife.org.
authors.forename: Katrina L
authors.initials: KL
authors.lastname: Counihan
authors.affiliation: US Fish and Wildlife Service Marine Mammals Management, 1011 East Tudor Road, MS 341, Anchorage, AK 99503, USA. Electronic address: verena.gill@boem.gov.
authors.forename: Verena A
authors.initials: VA
authors.lastname: Gill
authors.affiliation: Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Wildlife, 1451 Shaffer Road, Santa Cruz, CA 95060, USA. Electronic address: Melissa.Miller@wildlife.ca.gov.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Miller
authors.affiliation: Alaska Veterinary Pathology Services, 23834 The Clearing Drive, Eagle River, AK 99577, USA. Electronic address: avps.kbh@gmail.com.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Burek-Huntington
authors.affiliation: University of California Davis, School of Veterinary Medicine, Department of Pathology, Microbiology and Immunology, 4206 VM3A, One Shields Avenue, Davis, CA 95616, USA. Electronic address: rblefebvre@ucdavis.edu.
authors.forename: Rance B
authors.initials: RB
authors.lastname: LeFebvre
authors.affiliation: University of California Davis, School of Veterinary Medicine, Department of Pathology, Microbiology and Immunology, 4206 VM3A, One Shields Avenue, Davis, CA 95616, USA. Electronic address: bbyrne@ucdavis.edu.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Byrne
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D016667:Bacterial Capsules / Q000737:chemistry / Q000502:physiology; D018938:Caco-2 Cells; D002460:Cell Line; D004696:Endocarditis / Q000382:microbiology / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix / Q000737:chemistry / Q000502:physiology; D006801:Humans; D006820:Hyaluronic Acid / Q000032:analysis; D008264:Macrophages / Q000382:microbiology*; D051379:Mice; D050296:Microbial Viability; D010041:Otters / Q000382:microbiology*; D013291:Streptococcus / Q000145:classification / Q000302:isolation & purification* / Q000472:pathogenicity*
chemical_list: D006820:Hyaluronic Acid
keywords: Endothelial; Epithelial; Extracellular matrix; Infective endocarditis; Macrophage; Pathogenesis; S. infantarius subspecies coli; Sea otter