Toxinotyping of C. difficile strains
PL2
B2
PL3
A2
PL4
2.1 kb
2 kb
1.5 kb
2 kb
1.6 kb
PL1
B1
B3
A1
A3
2.5 kb
3 kb
2 kb
3 kb
3 kb
tcdR
N
H
tcdB
tcdE
Hc Hc H H
Ec
H
R
R
tcdA
tcdC
X
P
h
PCR method for screening changes in PaLoc
2 kb
h
S
EE
B1 PCR fragment
markers for toxinotyping
M. Rupnik
1
Institute of Public Health Maribor
2
3
4
5
A3 PCR fragment
6
7
Medical Faculty, University of Maribor
1 2 3 4 9
5 5 6 7 7 8
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Types of A-B+ C. difficile strains
toxinotype
characteristics
VIII
1.8 deletion in tcdA
stop codon at aa
position 47
>100
X
6 kb deletion in tcdA
rearrangement in
PaLoc
1
XVI
similar to
toxinotype V (A+B+)
not known
1
XVII
similar to
toxinotype X
not known
1
0-like
identical to
VPI 10463
not known
1
V-like
identical to
toxinotype V
not known
1
molecular basis for
TcdA non-production
number of strains
C. difficile typing – mostly used methods
Ribotyping
(Europe)
PCR of 16S-23S rDNA intergenic
spacer region
160 ribotypes
REA
(USA)
PFGE
(North America)
HindIII restriction of whole DNA
SmaI restriction of whole DNA
Stubbs, JCM 1999
>100 REA groups
(Rea Types)
no large international collection
Bidet, JCM 2000
Gerding D., Chicago, USA
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Large clostridial toxins (LCT)
C. difficile (TcdA, TcdB)
C. sordellii (TcsH, TcsL)
C. novyi (Tcna)
Thr
GTPaza
+
glc
Rho/Ras
UDP
toksin
Thr
Rho/Ras
• cytotoxicity
• glycosyltransferases
glc
GTPaza
• size (250-300 kDa)
+
UDP
• autocatalytic proteolysis
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C. difficile pathogenicity locus
(PaLoc)
PaLoc
19 kb
cdd1
cdu2'
cdu2 cdu1 tcdD
Hc
H
tcdB
Hc Hc
tcdE
H
Hc
tcdC
tcdA
P
P
P
Hc
cdd3
cdd2 cdd4
H
C. difficile VPI 10463
C. difficile toxcdu1
115 bp
cdd1
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