Gene regulation in Streptococcus pneumoniae - RePub - Erasmus ...

Resultss
and Discuussion
Gene regulation by RR09 in S. pneumoniae
In vivo characteristics
of TIGGR4∆rr09
PPrevious
sttudies
indiccated
that RR09 has a strain-sppecific
rolee
in pneum
virulencce,
as D39 wwith
deletioon
of the ressponse
regu ulator rr09 wwas
found to
be avirule
murine models testted,
while 00100993∆rrr09
was fou und to be aattenuated
oonly
upon in
infection
(3). Heree,
we extendded
these obbservations
s by analyziing
a TIGRR4∆rr09
mu
murine pneumonia
model oof
infectionn.
Mice in nfected inttranasally
wwith
10
TIGR4∆∆rr09
were found to hhave
significcantly
longer
survival times than
the pareental
strain (Fig. 1a). None of thhe
mice inf fected with the wild-ty
longer tthan
30 h affter
inoculation.
The leevel
of surv vival of micce
infected w
to 20% after 48 hh,
and nonee
of these mice surviv ved longer than 100 h
Furthermmore,
the TTIGR4∆rr09
9 bacterial ccounts
in BALF, B lungss,
and blood
were siignificant
rreductions
ccompared
tto
the wild d-type strainn
(P < 0.0
indicateed
that like 0100993∆∆rr09,
the TTIGR4∆rr09
9 mutant wwas
attenuat
infection
but was nnot
avirulentt
like D39∆rr09.
6 mococcal
ent in all
ntranasal
tant in a
CFU C of
mice infec cted with
ype strain survived s
with ∆rr09 dropped
h after inoc culation.
d showed th hat there
01) (Fig. 1b).
This
ted upon in ntranasal
Figure 1.
(A) Survivall
of mice after
intranasal innfection
with 10
value is <