Hayley Schmaley

Question 1

Q fever

Answer 1

50% seroconvert asymptomatic
50% experience Acute Q fever - influenza like
2% have chronic Q fever: endocarditis, difficult to treat (long term antibiotic treatment)
15% have long-term complications e.g. chronic fatigue

Question 2

Q fever transmission

Answer 2

Extremely infectious - 1 bacterium can cause disease
ticks are a reservoir but do not vector disease to humans
Farm animals –> excretion –> transmission (aerosols mostly/ingestion) –> humans (farmers, vets, abattoir workers)
Coxiella environmentall resistant
Q-vax: formalin-inactivated whole cell C.burnetii

Question 3

Coxiella biological weapon

Answer 3

Very infectious
Environmentally resistant
Easily spread
Incapacitating agent - significant public health outbreak
Developed by uSA and soviet union during cold war & Japan

Question 4

Netherlands coxiella outbreak

Answer 4

Densely packed farm animals + houses
Farmers noticed higher numbers of spontaneous abortions
Animals underwent mass vaccinations
Peak during dry hot weather

Question 5

Coxiella replication

Answer 5

Intravacuolar

Phagosome –> early endosome –> late endosome –> lysosome (4.5pH, proteolytic enzymes, most bacteria die)

Question 6

SCV

Answer 6

Small cell variant
Version that is environmentally resistant - heat, UV light, dessication, osmotic shock
–>LCV

Question 7

LCV

Answer 7

large cell variant
Bigger bacterium
Metabolically active

Question 8

Coxiella: replication in phagolysosome

Answer 8

Basic proteome
Production of acid phosphatase - inhibit NADPH oxidase limiting ROS production
DNA repair system upregulated under oxidative stress
Metabolically active at low pH

Question 9

Dot/Icm coxiella

Answer 9

Similar to legionella - functionally analogous, effector proteins are very different
Spans multiple membranes
Can’t replicate without Dot/Icm
Won’t start translocating effector molecules until its in lysosome

Question 10

Axenic growth coxiella

Answer 10

a lot of cysteine
5% cO2, low O2, 37C
ph~4.75

Question 11

B-lactomase reporter assay

Answer 11

Introduce plasmid that encodes b-lactamase
CCF2-Am enters cell + light –> fluorescence (green)
B-lactamase cleaves B-lactam ring –> blue light

Question 12

Dot/Icm effectors

Answer 12

Prevent host apoptosis
Contribute to fusogenicity of vacuole 
Mediate interaction with autophagosomes
Mediate cholesterol acquisition
130 effectors

Question 13

Dot/Icm effector identification

Answer 13

genomic fragments digested –> cloned into reporter

Question 14

Understanding coxiella effector functions

Answer 14

Examine localization e.g. mitochondria
Produce neutralizing antibodies
Biochemical and protein function studies

Question 15

Rickettsiae general

Answer 15

Diverse collection of obligate intracellular GN
Include Rickettsiae, Ehrlichia and Oreintia genera
Zoonotic: exist in animals in the wild
Transmitted to humans via arthorpod e.g. ticks, lice, fleas

Question 16

Rickettsiae biogroups

Answer 16

1. Spotted fever e.g. Rocky mountain
2. Typhus e.g. epidemic typhus
3. scrub typhus

Question 17

Rocky Mountain spotted fever

Answer 17

25% mortality rate, 4% with treatment

Rash: 2-5 days, centripetal spread

Question 18

RMSF transmission

Answer 18

Tick bites
Summer association
Transovarial: parent to offspring arthropod
Trans-stadial: passage from one developmental stage to subsequent stage - larvae, nymph, adult (infects rodent)

Question 19

Epidemic typhus

Answer 19

Rickettsia prowazekii
Unsanitary conditions
Spread by lice - defecation, scratch, bacteria enter

Question 20

Brill-Zinsser disease (chronic epidemic typhus)

Answer 20

Fever, chills, headache, myalgia
Rash: centrifugal spread - trunk spread to extremities
Complications: myocarditis

Question 21

Rickettsia endothelial cell entry

Answer 21

SFG Rickettsia OmpB binds Ku70 on endothelium - component of DNA-dependent protein kinase
Cholesterol dependent
Breaks out of phagosome - phospholipase and haemolysin
Typhus: replicate in cytosol until host cell ruptures
SFG: mediate actin-dependent movement

Question 22

RickA

Answer 22

No Arp 2/3 in tails

Participates in invasion, not movement

Question 23

ScaA

Answer 23

Identified by bioinformatics

Nucleate unbranched actin filaments

Question 24

Rickettsia virulence factors

Answer 24

Type 4aSS: different to DotIcm, upregulated during intracellular growth in some species
Protein and DNA transfer

Question 25

Chlamydia

Answer 25

Obligate intracellular pathogen Require host to replicate - vacuolar pathogen Small genome - reductive evolution Lack metabolic and biosynthetic pathways Dependent on host - ATP, aa 9 species - 2 affect humans

Question 26

Chlamydia trachomatis

Answer 26

19 serovars based on outer membrane protein

Question 27

C.trachomatis A-C

Answer 27

Blinding trachoma: leading cause of blidness Severe problem in Aboriginal communities Inflammation in the eye -->entropian (eyelid turns in), trichiasis (eyelashes touch eyeball) --> cornea undergoes trauma -> blindness TRANSMISSION: close contact, fomites, flies, aerosol, secretions

Question 28

SAFE strategy

Answer 28

S: surgery A: antibiotic distribution F: facial cleanliness - remove source and transmission E: environmental improvements - hygiene, decreasing flies, health education

Question 29

C.trachomatis D-K

Answer 29

Sexually transmitted form Urogenital tract infection 70% women, 50% men infected are asymptomatic

Question 30

Chlamydia D-K Symptoms

Answer 30

Men: urethritis, proctitis Women: Cervicitis, Pelvic inflammatory disease --> infertility, proctitis

Question 31

L1-L3 chlamydia

Answer 31

LGV: Invasive --> severe inflammation Systemic symptoms, genital ulcers Can lead to chronic granulomatous inflammation, lymphatic obstructions, fibrosis and strictures

Question 32

Chlamydia pneumonia

Answer 32

Animal kingdom but species specific strains Respiratory disease: 10% of community acquired pneumonia, asymptomatic Transmission: aerosol Link to chronic diseases: CVD, arthritis, diabetes

Question 33

C.pneumoniae persistence

Answer 33

Immune cell recruitment to site of infection IFNg detected by infected cell --> upregulates IDO IDO degrades tryptophan --> KYN --> less tryptophan Bacteria detects low tryptophan (needed to replicate) IFN decreases, IDO decreases, tryp increases --> reactivation of inection Nonreplicating - not going to be affected by antibiotics

Question 34

Chlamydia - Koala

Answer 34

C.percorum: main agent, causes blindness and infertility in females C. pneumoniae: rhinitis and pneumonia Treatment: antibiotics intolerant, need to capture it (wild koalas stressed in captivity)

Question 35

Chlamydia developmental cycle

Answer 35

EB (elementary): infectious, environmentally resistant, smaller than RB RB (reticulate body): replicative form EB taken up by host cell --> start to revert to RB --> replicate --> revert back to EB when nutrients are taken up

Question 36

Elementary bodies

Answer 36

Not producing RNA, proteins Metabolically inactive Osmotically stable

Question 37

Reticulate bodies

Answer 37

Not infectious | More transcriptionally active

Question 38

Chlamydiae entry

Answer 38

Invade most cells Initial interaction between heparan sulfate proteoglycans --> 2nd interaction (high affinity) - mannose, estrogen, platelet-derived growth factor receptor

Question 39

Chlamydiae intracellular niche

Answer 39

``` Avoids fusion with lysosome Delayed maturation (EB?) Actively modify host trafficking Traffics along microtubules --> Golgi Directs homotypic fusion of inclusion - multiple chlamydia will end up in same inclusion e.g. quorum sensing ```

Question 40

Chlamydiae T3sS

Answer 40

25 genes Molecular syringe Not encoded in pathogenicity island - spread throughout chromosome (4 gene clusters) 1.EB preloaded with T3S effectors 2. Maximum contact between early RB and inclusion membrane surfaces 3. RB replication - early inclusion 4. Physical detachment provokes T3S inactivation with induction of late effectors - mid to late inclusion

Question 41

T3SS effectors chlamydia

Answer 41

~50-100 effector proteins Preloaded effectors/invasion: e.g. TARP: Translocated actin-recruiting phosphoprotein - movement of vacuole Prevent fusion between inclusion and lysosomes Divert host cell trafficking to inclusion to provide nutrients and constituent molecules required for bacterial replication e.g. Inc Proteins - localize inclusion, Rab, SNARES

Question 42

IncA

Answer 42

Fusion of inclusions | Has SNARE like motifs

Question 43

IncD

Answer 43

Interact with ER and creating contact site where ER and inclusion are close Interacts with CERT: transports ceramide between ER and Golgi (lipid building block) CERT localises to inclusion and binds to IncD - Chlamydia can acquire ceramide