Yersinia Flashcards
Yersinia description
Gram negative, lactose negative, bipolar staining in smears, most motile (except Y. pestis)
Yersinia Important species
Y. ruckeri (fish) - enterocolitica (domestics & primates) - pseudotuberculosis (birds,rodents, domestics, primates) - **Y. pestis (Plague! zoonosis, rodents, cats)
Yersinia pestis - Most known as
The bubonic plague! Bioweapon - Rodent based zoonotic disease
Yersinia pestis Presentations
Local lymphadenitis (bubonic plague) - Pneumonia (pneumonic plague, 50% fatal) - Septicemia (septicemic plague, fatal if untreated)
Yersinia pestis virulence factors
Incomplete LPS (no O-Ag) - Pla - Hms - Yops & LcrV - Ymt - Gsr
Pla
enhace visceral colonization, bacterial metastasis
Hms
Iron acquisition, colonization of flea proventriculus***
Yops & Lcrv
Effector proteins act as toxins
Ymt
protects bacteria from digestive enzymes in flea
Gsr
Survival of bacteria in phagolysosome in macrophages
Yersinia pestis reservoir
Rodents! Endemic areas: intermediate hosts- squirrels, prairie dogs, rats, rabbits
Yersinia pestis Transmission
Fleas, airborne, oral
Yersinia pestis pathogenesis
First intracellular, then extracellular* Fleas feed–> bacteria blocks proventriculus & contaminates feeding site –> bacteria killed at sige by PMNs & inflammation –> some survive in macrophages–> induce apoptosis–> secrete proteins –> further survival–> extracellular survival
Yersinia pestis in humans
Traced to feline infection - 15% fatality with treatment - Inoculation via cuts, bites, scratches, airborne, flea borne, ingestion of infected meat or necropsy exposure
Yersinia pestis in cats
Ingest infected prey - Regional lymphadenitis - Symptomatic cases are fatal - Cat & dog flease (Ctenocephalides) doesn’t transmit bacteria (no proventricular blockage)
Yersinia pestis Culture
Blood or chocolate agar, stain with Wayson’s or gram stain
Yersinia pestis treatment
Report suspected feline plague!! (isolate, treat for fleas) no vaccines
Yersinia pseudotuberculosis
Worldwide - cold months - Birds & rodents, occasionally cats
Yersinia pseudotuberculosis in birds & rodents
Mesenteric lymphadenitis - terminal ileitis - acute gastroenteritis - septicemia
Yersinia pseudotuberculosis virulence factors
Ail - Inv * Yad - Very similar to Y. pestis
Yersinia pseudotuberculosis Ail
Adhere M cells, protects from complement
Yersinia pseudotuberculosis Inv & Yad
Adherence to M cells & basolateral ileal epithelial cells - Yad protects from complemen
Yersinia pseudotuberculosis pathogenesis
Similar to pestis - Intracellular then Extracellular
Yersinia pseudotuberculosis disease patterns
Diarrhea (PMN recruitment & PG release) - Septicemia (immune system exhausted during local phase) - Necrosis of intestinal wall, abdominal lymph nodes, visceral organs
