Gene exchanges Gene regulation Gene products Gene product ...€¦ · Virulence Gene Regulation by...
Transcript of Gene exchanges Gene regulation Gene products Gene product ...€¦ · Virulence Gene Regulation by...
Staphylococcus aureus Pathogenesis
- Gene exchanges
- Gene regulation
- Gene products
- Gene product cooperation
Brussels 07
Host
Species
Coagulase
Clumping factor
Virulence
Human and other primates
S. aureus S. epidermidis S. capitis S. caprae S. saccharolyticus S. warneri S. pasteuri S. haemolyticus S. hominis S. lugdunensis S. auricularis S. saprophyticus S. cohnii S. xilosus S. simulans S. schleiferi
++ - - - + - - - - - - - - - - +
++ - - - - - - - - + - - - - - +
+++ +
(+) (+) - - - +
(+) +
(+) + - - - +
Carnivores S. intermedius S. felis
+ -
- -
++ ++
Some Staphylococcal Species from Mammals
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Baba T et al. Lancet 2002;359:1819
Whole genomes of S. aureus MW2, N315 and Mu50
MW2
N315
Mu50
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- GC content- Gene comparison- Codon usage- Genometrics
From Linguistics to Genometrics
theicaacisagreatconférenceparcequellegathermanygreatscientists
theicaacisagreatconférenceparcequellegathermanygreatscientists
http://www2.unil.ch/comparativegenometrics/
CA Roten and L. Guy
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Guy Lionel, Thesis 2007
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S. aureus Genometric Analysis
Baba T et al. Lancet 2002;359:1819
Methicillin resistance
Whole genomes of S. aureus MW2, N315 and Mu50
MW2
N315
Mu50
Provirus encoding
PVL toxin
tst1
set
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- DNA region (up to 200 kb) of foreign origin
- Contain pathogenic genes
- May have a different GC content
- Flanked by direct repats of IS
- Associated with tRNA genes
- Contain relics of integrase/excisase genesor of phage genes
Define Pathogenicity Islands
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Hacker J et al. Mol Microbiol 1997; 23:1089-97
- Transformation
- Conjugation
- Transduction (generalized)
How do they move ?
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attatt
int
The example of SaPI1
Moving Genes Around
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attatt
int
xis
Moving Genes Around
The example of SaPI1
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attatt
int
xis
Moving Genes Around
The example of SaPI1
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Moving Genes Around
The example of SaPI1
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attatt
int
Moving Genes Around
The example of SaPI1
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Novick, Schlievert, Ruzin. Microbes and Infect 2001; 3:585
Moving SaPI1 with Phage 80α
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Staphylococcus aureus Pathogenesis
- Gene exchanges
- Gene regulation
- Gene products
- Gene product cooperation
Brussels 07
Time
Growth
Transcriptionof exoproteins
Transcriptionof adhesins
agr-Regulation of Virulence DeterminantsDuring in vitro Growth of S. aureus (1)
Adapted from R.P. Novick ASM press, 2000
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AIP = auto-inducing peptide
A C D B
P2 P3
AgrB
AIP
AgrC
AgrA
δ
RNAIII
P
Novick et al. Curr. Op. Microbiol. 1999;2:40-45
Virulence Gene Regulation by Peptides in S. aureus (1)
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A C D B
P2 P3
AgrB
AIP
AIP = auto-inducing peptide
AgrC
AgrA
δ
RNAIII
AgrAP
Activation of Tx
Virulence Gene Regulation by Peptides in S. aureus (2)
Novick et al. Curr. Op. Microbiol. 1999;2:40-45
Translationof exoproteins
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Regulation of S. aureus super-antigens
Action of regulatory genes
Gene Product Activity/function agr Sae-RS
rot sarA sarS sarT tst
Superantigens
sea Enterotoxin A Food poisoning, TSS 0 0
seb Enterotoxin B Food poisoning, TSS + b -sec Enterotoxin C Food poisoning, TSS +sed Enterotoxin D Food poisoning, TSS +eta Exfoliatin A Scalded skin syndrome +etb Exfoliatin B Scalded skin syndrome +tst Toxic shock toxin-1 Toxic shock syndrome + - b -
0, no effect of gene on expression; +, upregulated; -, downregulated. b. Controversial.
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Host:- Lack of anti-TSST antibodies
Environment:- High protein concentration
- Neutral pH
- High pCO2
- High pO2
Conditions for Developing Toxic Shock Syndrome
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AlteredEcology !
Staphylococcus aureus Pathogenesis
- Gene exchanges
- Gene regulation
- Gene products
- Gene product cooperation
Brussels 07
Gene Protein Function Implication in disease
spa Protein A Binds Fc fragment Sepsis, osteoarthritis
clfA Clumping factor A Binding to fibrinogen Endocarditis
clfB Clumping factor B Binding to fibrinogen -
cna Collagen binding protein Binding to collagen Osteomyelitis
fnA Fn-binding protein A Binding to fibronectin Endocarditis, persistence
fnB Fn-binding protein B Binding to fibronectin -
sdrC Serine-aspartate repeat prot Binding to fibrinogen -
sdrD Serine-aspartate repeat prot Binding to fibrinogen ? -
sdrE Serine-aspartate repeat prot Binding to fibrinogen ? -
pls Plasmin-sensitive protein Binding to nasal mucosa Nasal colonization?
fmtB Methicillin resistance Putative cell-wall building Expression of methi-R
sasA S. aureus surface protein A Undetermined -
sasB S. aureus surface protein B Undetermined -
sasC S. aureus surface protein C Undetermined -
sasE S. aureus surface protein E Undetermined -
sasF S. aureus surface protein F Undetermined -
sasG S. aureus surface protein G Binding to nasal mucosa Invasive disease
sasH S. aureus surface protein H Undetermined Invasive disease
sasI S. aureus surface protein I Undetermined -
sasJ S. aureus surface protein J Undetermined -
sasK S. aureus surface protein K Undetermined -
Understanding Pathogenic FactorsWild Type Coa- Coa-/ClfA- Coa-/ClfA-/Fnb-
Coagulation
Vegetations
PlateletFactors
Tissuefactor
??
???
??
? ???
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Transfer or Staphylococcal Pathogenicgenes into less Virulent Bacteria
S. aureus donor(Coa+/ClfA+/Fnb+)
Lactococcusrecipient (ClfA-)
1: Transfer of S.aureus clfA geneinto viridans group streptococcus
2: Select clumping-positiverecombinants
Lactococcusrecombinant (ClfA+)
Que et al. I&I 2000; 68:3516-22Brussels 07
Adherence of L. lactis to PMMA coverslips coated with fibronectin
8325-4
pIL253
FnbpA (+) 8325-4
Adh
eren
t CFU
(x10
3 /cov
ersl
ip)
20
40
60
80
100
0
Soluble concentration of Fn (µg/ml)
0.0 0.25 0.50 0.75
Que et al, I&I 2001; 69:6296-302 Brussels 07
ExperimentalEndocarditis
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% In
fect
ed V
eget
atio
ns
100
20
40
60
80
0
L. lactis parent ClfA+ FnBPA+
Inoculum = 104 105 106 107 104 105 106 107 104 105 106 107
Infectivity of L. lactis Recombinants Binding to Fibrinogen or Fibronectin
Que et al. Infect. Immun. 2001Brussels 07
Log
CFU
/g V
eget
atio
ns
10
2
4
6
8
0
L. lactis parent ClfA+ FnBPA+
Time after infection (h) = 2 12 48 72 2 12 48 72 2 12 48 72
Dynamic of L. lactis Endocarditis
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Que et al. J. Exp. Med . 2005
ExperimentalEndocarditis
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Neighboring Aorta of Valves Infected with ClfA-positive Lactococci /Gram Stain
Que YA, J. Exp. Med 2005;201:1627Brussels 07
Que YA, J. Exp. Med 2005;201:1627 Brussels 07
Membrane Peptidoglycan
Binding Domains of FnBPA
Binding toFibrinogen Fibonectin
ClfA +++ -
FnBPA ++ +++
and Piroth et al. 2007, submittedQue YA, J. Exp. Med 2005;201:1627
M-LPXTG W D1-4 Du C B A L
Fibronect. Fibronect. Fibronect. Fibrinogen Leader
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Membrane Peptidoglycan
Binding Domains of FnBPA
M-LPXTG W L
M-LPXTG W D1-4 Du C L
M-LPXTG W A L
M-LPXTG W D1-4 Du C B A L
Fibronect. Fibronect. Fibronect. Fibrinogen Leader
Brussels 07and Piroth et al. 2007, submittedQue YA, J. Exp. Med 2005;201:1627
Binding Domains of FnBPA
Surrogaterecombinant Binding Infection Internalization Persistence
Fg +++ --- ---
Fn --- +++ ---
cis Fn/Fg +++ +++ +++
trans Fn/Fg +++ +++ +++
Brussels 07and Piroth et al. 2007, submittedQue YA, J. Exp. Med 2005;201:1627
- S. aureus needs both fibrinogen- and fibronectin-binding domains to be fully infective
- Fibronectin-binding protein represents an exampleof intra-molecular domain cooperation
- Fibronectin- and fibrinogen-binding represent anexample of inter-molecular domain cooperation
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E. Widmer et al. I&I , submitted Brussels 07
Que YA, J. Exp. Med 2005;201:1627 Brussels 07
Que YA, J. Exp. Med 2005;201:1627 Brussels 07
Que YA, J. Exp. Med 2005;201:1627
LPXTG-proteins Toxins
S. aureus 21 > 30
S. epidermidis > 10 No
S. haemolyticus 6 No
S. saprophyticus 1 No
But all have prophages and genomic islands,including the SCC staphylococcal K7 chromosome
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Staphylooccus aureus
a paradigm of host-parasite evolution
N. WidmerM. Giddey J. EntenzaS. PiuJ. Vouillamoz
YA QueL PirothCA. RotenL. GuyF. Collyn
Subcutaneous Infection of Mice with 108 CFU of AIP IS. aureus supplemented or not with AIP II
Lesi
on s
ize
in m
m2
1000
200
400
600
800
0
Day 1 Day 5n = 4 4 3 4 4 4 3 4
Strain 6390B, agr+Strain 6911 , agr-
6390B + 10 μg AIP II6390B + 5 μg AIP II
Mayville et al. PNAS 1999; 96:1218-1223
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- No, not sensu stricto
- All Staphylococcus spp. carry an agr
- agr is also required for regulationof house-keeping genes
Is agr a Virulence Factor ?
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