Salmonella

Enterobacteriaceae

salmonella is a member of this family..

Gram negative bacilli

gram stain and shape of salmonella spp

Gastroenteritis

salmonella causes

Contaminated food

salmonella infections are associated with

Typhoidal and non typhoidal

salmonella infection types…

Typhoidal

disseminated salmonella infection with prolonged high fever, headache, loss of appetite, and bradycardia

Non typhoidal

salmonella infection that causes acute diarrhea, abdominal cramps and fever, resolves in 1-7 days without treatment but causes complications in immune compromised hosts

2700

number of salmonella serovars

Humans

typhoidal salmonella is highly adapted to infect

Humans and animals

non typhoidal salmonella is infectious to __

Flagella

motility of salmonella is associated with, also facilitates adherence and biofilm formation

FliC and FljB

salmonella enterica experesses these two antigenically distinct flagellins

TLR5

flagellins of salmonella activate….

T3SS

flagellins are secreted through __ to promote inflammation

Fimbrial gene clusters (FGC)

over 30 ____ have been identified on salmonella chromosome and plasmids and produce type 1 fimbraie needed for adherence

Type 1

type of fimbriae produced by FCGs

Long polar fimbriae (Lpf)

mediated adherence to M cells and epithelial cells, phase variable to limit immune recognition

Plasmid encoded fimbriae (PEF)

lacks a tip adhesion, binds GalB1-4 GLcNAC (Lewis X blood group antigen) and is involved in adhering to various cell lines

23

how many Salmonella pathogenicity islands SPIs have been identified in salmonella spp

SPI1

encodes T3SS that mediates invasion of non phagocytic cells through the trigger mechanism

SipA and SipC

effectors (from T3SS) that bind actin, preventing depolarization and are used in the trigger mechanism

SopB, SopE, SopE2

trigger Rac/CDC42/RhoGTpases that facilitate actin remodeling

SptP

involved in recovery of host cytoskeleton after bacterial internalization with the trigger mechanism

Trigger Mechansim

salmonella invasion technique with SPI 1 effectors

Zipper mechanism

salmonella invasion mediated by 2 membrane proteins

Rck

interacts with epidermal growth factor on host cell membrane (zipper)

PagN

attaches to cell surface heparin sulfate proteoglycans (zipper)

Phosphoinositide 3 kinase

binding of PagN leads to phosphorylation of ___ in the zipper mech

Akt kinase

phosphorylated P3K activates ____ and Rac1 and Cdc42 (small gtpases) which all of which lead to Arp2/3 activation and actin remodeling

SCV

important for replication of bacterium, DOES NOT FUSE WITH LYSOSOME, occurs in many cell types including macrophages

T3SS1 and SPI2 encoded T3SS2

needed for establishment of SCV

Early

T3SS1 effectors are used for ___ stages of SCV biogenesis

Later and maintenance

T3SS2 effectors are required for ___ stages of SCV biosynthesis

28

how many effectors translocated by T3SS2

T3SS2

effectors used to modulate intracellular environment and maintain SCV integrity, position the SCV near the golgi apparatus and modulate host cell functions (antimicrobials)

SseJ

binds to RhoA to localize to cytoplasmic side of SCV and functions as a glycerophospholipid GCAT to modify vacuole membrane composition (establishment of SCV)

SifA

forms falmonella induced filaments (SIFs) and salmonella induced SCAMP3 tubules (SISTs) in infected cell

SIF and SISTs

membrane tubules that extend from the SCV and associate with cell microtubule network

Apoptosis

a problem with the SCV is that other T3SS2 effectors trigger ___

SpvB

ADP ribosyltransferase toxin that promotes actin depolymerization and vacuolation (problem with SCV apoptosis T3SS2 effector)

SseL

deubiquitinates proteins bound for degradation to limit cytotoxicity and autophagy of host cell, allowing salmonella to replicate more (problem with SCV apoptosis T3SS2 effector)

SlrP

ubiquinates thioredoxin to promote degradation (problem with SCV apoptosis T3SS2 effector)

GtagA, GogA, PipA

promote NFkB degradation and are a way salmonella can modulate immune signaling

SpvC

dephosphorylates ERK/P38/MAPK and are a way salmonella can modulate immune signaling

SspH2

ubiquitinates NOD which promotes inflammation and are a way salmonella can modulate immune signaling

A2B5

typhoid toxin is an ab toxin with these subunits …

PltA

adp ribosyltransferase covalently linked to CDT in typhoid toxin, target unknown but facilitates toxin release from bacterium

CDT

functions as nuclease and leads to G2/M cell cycle arrest (typhoid toxin)

PltB

homopentamer bind glycans on host cells and elads to emboli that responsible for rose spots in typhoid toxin infection

NTS

strains of salmonella treated with antibiotics

Salmonella typhi

vaccinations against ____ are moderately successful