Lecture 23 - Yersinia Flashcards
(24 cards)
describe the yersinia genus and list the 3 human pathogens
- Enterobacteriaceae, G-ve rod
- 14 species
- pathogens = enterocolitica, pseudotuberculosis, pestis
describe y enterocolitica’s disease, transmission and biogroups
- yersiniosis = self-limiting gastroenteritis -> terminal ileitis, mesenteric lymphadenitis, septicaemia
- faecal-oral by contaminated food/water
- pig reservoir
- biogroups 1A, 1B, 2-5
describe y pseudotuberculosis’ disease, transmission and serogroups
- Enteric = acute gastroenteritis, mesenteric lymphadenitis and diarrhoea, pseudoappendicitis
- various animals, water, environ, food, can grow @ 4C
- 21 serogroups = LPS variations
describe Y pestis’ evolution, disease, life cycle
- evolved from Y pseudotuberculosis
- plague = severe, acute, rapid progressing febrile + significant mortality
- plague types = bubonic, septicaemic, pneumonic
- sylvatic life cycle = wild animals before humans
list the 3 great plagues of y pestis
- Justinian plague AD542-570 = 70k dead in 2yrs, africa to egypt and mediterranean
- Black death = 14-16th cent, 30+ mil dead, Asia to europe
- 1890 china, 12.5mil dead
describe y pestis related plague outbreaks in the 90s
- rural/agricultural africa
- 1994 indian bubonic then pneumonic plague in Beed and Surat districts from domestic rats = migration
- china/mongolia eating marmots = quarantine
describe Y pestis’ transmission and symptoms
- transmission = infected flea bite, inhaling infected droplets, direct contact
- symptoms = headache, nausea, aching joints, malaise
describe the transmission and features of bubonic plague
- transmission = bite/direct contact to lymph nodes
- symptoms = buboes node inflammations, haemorrhagic spots, high fever, delirium, 50-60% untreated fatality
describe the transmission and features of pneumonic plague
- transmission = inhalation of droplets to lung
- symptoms = coughing, slimy bloody sputum to free flowing red sputum
- 95-100% untreated death
describe the transmission and features of septicaemic plague
- in blood
- symptoms = high fever, rash, gangrene, resp failure, deep red = black death name
- 100% fatality
what are the 3 possible human transmission locations of yersinia?
- bite/direct contact = pestis to lymph node = bubonic/lungs
- inhalation/to lungs = pestis = pneumonic plague
- pseudotuberculosis/ingested enterocolitica to M cells to macrophages to node then sometimes systemic
list the 7 pathogenic components/virulence factors of Y pestis
- biofilms for flea colonisation
- phospholipase D for survival in fleas
- capsule
- OMP serum resistance
- Pla protase = dissemination
- regulatory rewiring = increased VFs
- cryptic plasmids
list the 5 pathogenic components/virulence factors of enteropathogenic Y spp
- biofilms = environ survival
- solute transport = nutrients
- motility
- urease = acid survival
- CU and OMP adhesins = colonisation
what is the transport/secretion system used by both Y pestis and enteropathogenic spp and what does it do?
T3SS Ysc-Yops = anti-phagocytosis and immune suppression
list the 3 virulence plasmids associated with pathogenic yersinia
- pPCP1/pPla = Pla protease = dissemination
- pMT1/pFra = murine toxin and F1 capsular antigen = flea transmission
- pCD1/pYV = low Ca response T3SS and Yops = avoid immune
which virulence plasmid encodes the F1 capsular antigen and what are the features of the antigen?
- pMT1/pFra
- Polypeptide capsule @ 37C visible by light microscopy
- Antiphagocytic, antigenic
- important but not essential
- Required for survival in rat flea midgu
which virulence plasmid encodes the yersinia murine toxin (Ymt) and what does the toxin do?
- pMT1/pFra
- intracellular phospholipase D (PLD) = protection from cytotoxic digestion = colonise midgut
- Required for survival in rat flea midgut
which virulence plasmid encodes plasminogen activator and what does the activator do?
- pPCP1/pPla
- Protease = cleaves host proteins for infection eg fibrin
- dissemination and immune evasion
which virulence plasmid encodes T3SS/Ysc-Yops and what does the T3SS do?
- pCD1/pYV @ 37C with Ca
- yersinia effector proteins (Yop) = subvert host signalling, apoptosis, inhibit phagocytosis and immune cells
list the 8 (in 6) Yops and their functions
- YopE = cytotoxic, disrupts cytoskeleton
- YopH = PTPase, disrupts adhesions
- YopM = E3 ubiquitin ligase = necrosis
- YpkA/YopO = Ser/Thr kinase, rounds up cells
- YopP/YopJ = cytotoxic, macrophage apoptosis, inhibits TNF-alpha
- YopT = cytotoxic, disrupts actin
what is the role of LcrV in T3SS of yersinia? compare to LcrV negative mutants
- LcrV = part of pore complex in T3SS injectisome
- Lack of it = secrete Yops into extracellular which are only cytotoxic if intracellular
describe yersinia’s reliance on Ca
- Low Ca response (Lcr) = grown @ 37C but requires Ca
- mimimal Ca = stop growth + inject Yops extracellular
what do yersinia’s invasins bind and what is the subsequent response? which species is it found in?
- Chromosomal in pseudotuberculosis and enterocolitica + pseudogene in pestis
- host beta1-integrins in small intestine epithelia
- rearrange host cytoskeleton = phagocytosis into epithelia
what is the function of the YadA adhesin and which species possess it?
- expressed @ 37C, docking system for T3SS to contact target PM for Yop delivery
- required for enterocolitica, not pseudotuberculosis, pseudogene in pestis
