Molecular pathogenesis and Prevention of Staphylococcus ... · Staphylococcus aureus, that is both required for disease pathogenesis and, when offered to the immune system 26 of experimental

Molecular pathogenesis and Prevention of Staphylococcus aureus infections

Prof. Olaf Schneewind

1The screen versions of these slides have full details of copyright and acknowledgements

Molecular Pathogenesis and Prevention of Staphylococcus aureus Infections

1

Prof. Olaf SchneewindLouis Block Professor and Chair,

Department of MicrobiologyUniversity of Chicago

920 East 58th Street, Chicago, IL 60637

• About 4% of hospital admission in the United States acquire S. aureus infections

• Leading cause of bloodstream, lower respiratory tract, skin & soft tissue infections

• Many staphylococcal hospital infections caused by methicillin-resistant (MRSA) strains

Staphylococcus aureus

2

• Many community acquired (CA) infections caused by CA-MRSA

• Annual US mortality exceeds that of HIV/AIDS or any other infectious disease

• FDA licensed vaccine not available

The envelope of Gram-positive bacteria

3J.L. Strominger, J.M. Ghuysen and D.J. Tipper (1965)




Protein A

4O. Schneewind et al.; Navarre et al.

Sortase A - anchoring proteins in the envelope of Gram-positive bacteria

5S. Mazmanian et al.

S. aureus sortase A mutants

6S. Mazmanian et al.




Sortase A cleavage of LPXTG peptides

7Ton-That et al.

Fluo

resc

ent

inte

nsity

(A

rbitr

ary

unit)

Sortase A catalyzed transpeptidation

8Ton-That et al.

LPXTG peptide bound to sortase A

9Zhong et al.




Deposition of protein A in the staphylococcal envelope

hibi

tion

(min

utes

)

10A. DeDent et al.

Tim

e fo

llow

ing

tryp

sin

inh

Protein A on the staphylococcal surface

11A. DeDent et al.

Signal peptides of staphylococcal surface proteins

12A. DeDent et al.




Distribution of surface proteins in the cell wall envelope

αClfA

spa-

spa-

Alexa647-IgG

+YSIRK

DIC Merge

αSasF

DICAlexa647-

IgG

-YSIRK

Merge

spa-

spa-

13A. DeDent et al.

spa/clfA-

spa-

spa-

/sdrD-

αSdrD

spa/sasF-

αSasA

spa-

spa-

/sasA-

Signal peptides address surface proteins to specific envelope locations

14A. DeDent et al.

Protein traffic to the cell wall envelope of Staphylococcus aureus

15A. DeDent et al.




Fate of Staphylococcus aureus Newman injected into the bloodstream of mice

• Staphylococcus aureus Newman is inoculated directly into the mice’s blood stream

• We use about 107 cfu

• Immediately after injection the organism resides in the blood and distributed into the peripheral tissues

16

in the blood and distributed into the peripheral tissues

Staphylococcal abscess formation in the kidney of mice

17

Architecture of day 2 lesions

Day 2

18




Architecture of day 5 lesions

Day 5

19

Scanning electron microscopy of staphylococci in host tissues

20A. Cheng et al.

Sortase mutants cannot form abscesses

21




Sortase A is essential for staphylococcal persistence in host tissues

22A. Cheng et al.

Sortase mutants in renal tissue

23A. Cheng et al.

Surface abscesses

24A. Cheng et al.




Surface proteins involved in abscess formation and persistent infection

25A. Cheng et al.

Hypothesis

• A protective antigen can be thought of as a genetic and biochemical entity within microbes, here Staphylococcus aureus, that is both required for disease pathogenesis and, when offered to the immune system

26

of experimental animals in isolated form, ableto generate protective immunity against this disease

– What are the protective antigens of staphylococci?

Surface proteins and protective immunity

27Y. Stranger-Jones et al.




Vaccine protection against staphylococcal abscess formation with IsdAB/SdrDE

28Y. Stranger-Jones et al.

Staphylococcal abscesses enable persistence

29A. Cheng et al.

Heme-iron transport in staphylococci

30S. Mazmanian et al.E. Skaar et al.

Fe




Sortase B and the IsdC anchor structure

31L. Marraffini et al.

Protein topologies in the cell wall of staphylococci

32SrtBSrtA

L. Marraffini et al.

Staphylococcal envelope associated proteins

Envelope associated

proteinAA residues Ligand Association

Emp 341Fibronectin, fibrinogen

SDS extractable

33

Ebh 10498 Fibronectin Membrane protein

Efb 165Complement factor

C3bSecreted, weak

association

EbpS 486 Elastin Membrane protein

Eap/Map 689 Plasma proteins SDS extractable




Eap and Empwild-type

34A. Cheng et al. emp emp (pEmp)

Staphylocccal load and persistence when lacking envelope associated proteins

35A. Cheng et al.

Eap mutants form abscesses

36A. Cheng et al.




Emp mutants cannot form abscesses

37A. Cheng et al.

Distribution of Eap and Emp during staphylococcal abscess formation

38A. Cheng et al.

Eap and Emp vaccines

39A. Cheng et al.




Vaccine protection against lethal Staphylococcus aureus challenge

40Y. Stranger-Jones et al.H. Kim et al.

Staphylococcus aureus and human lung infections

• Community-acquired staphylococcal pneumonia, particularly frequent in children, young adolescents and elderly patients

• Hospital-acquired staphylococcal pneumonia of individuals with ventilator-assisted respiration

41

with ventilator assisted respiration

• Hospital-acquired staphylococcal pneumonia occurs frequently in patients with cardiothoracic surgery

• High mortality

• Human pneumonia is more often caused by methicillin-resistant (MRSA) than by methicillin-sensitive S. aureus (MSSA) strains

Staphylococcus aureus pneumonia in mice

010203040

6050

708090

100

Perc

ent m

orta

lity

Newman strA strB spa icaA

42J. Bubeck-Wardenburg

Newman strA- strB- spa- icaA-

010203040

6050

708090

100

Perc

ent m

orta

lity

Newman agrA- hla-




Murine pneumonia model


Mechanisms of alpha-hemolysin (Hla) assembly and function

44M. Montoya and E. Gouaux (2003) BBA 1609:19-27

Alpha-hemolysin is an essential virulence factor for S. aureus pneumonia





Active immunization with the Hla protects against staphylococcal pneumonia


Passive immunization with Hla antibodies protects against staphylococcal pneumonia


University of ChicagoTed BaeAlice ChengAndrea DeDentMatt FrankelHwan KimGwen Liu

Support• National Institute of Allergy

& Infectious Diseases research awards RO1-AI038897 and RO1-AI52474

• (Region V) Great Lakes Regional Center of Excellence for Biodefense and Emerging Infectious Diseases (U54-AI057153)

Acknowledgements

48

Sarkis MazmanianMolly McAdowWilliam NavarreEric Skaar Vilasack ThammavongsaHung Ton-ThatYukiko Stranger-JonesLuciano MarraffiniJuliane Bubeck Wardenburg

( )• Novartis Vaccines & Diagnostics

Collaborations• Dominique Missiakas (University of Chicago)• Andrzej Joachimiak

(Argonne National Laboratory)• Shantam Narayana

(University of Alabama, Birmingham)• Fabio Bagnoli, Guido Grandi and Rino

Rappuoli (Novartis Vaccines & Diagnostics)




49

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Molecular pathogenesis and Prevention of Staphylococcus ... · Staphylococcus aureus, that is both required for disease pathogenesis and, when offered to the immune system 26 of experimental