752-
4001
-00
VM
ikro
biol
ogie
Lect
ure
Hum
an -
Mic
robe
Inte
ract
ion
Dec
embe
r 3M
arku
s S
chup
pler
Con
tent
base
d on
Bro
ck 1
3/E
, Cha
pter
27:
Mic
robi
al In
tera
ctio
ns w
ith H
uman
s
•Wha
t is
norm
al m
icro
flora
ass
ocia
ted
with
var
ious
bod
y si
tes?
–sk
in–
oral
cav
ity–
gast
roin
test
inal
trac
t–
resp
irato
ry tr
act
–ur
ogen
ital t
ract
•How
are
bac
teria
l inf
ectio
ns tr
ansm
itted
?
•Wha
t are
the
mec
hani
sms
of p
atho
gene
sis?
•How
to m
easu
re v
irule
nce?
•Wha
t are
bac
teria
l viru
lenc
e fa
ctor
s?
•Wha
t are
the
maj
or ty
pes
of b
acte
rial t
oxin
s an
d ho
w d
o th
ey w
ork?
Def
initi
ons
•N
orm
al fl
ora:
mix
ture
of m
icro
orga
nism
s us
ually
foun
d at
any
anat
omic
al s
ite in
a h
ealth
y or
gani
sm
•Pa
rasi
te:
an o
rgan
ism
that
gro
ws
in o
r on
a ho
st
caus
ing
dam
age
•Pa
thog
en:
a m
icro
bial
par
asite
that
har
ms
mic
robi
al h
ost
•Pa
thog
enic
ity:
abili
ty to
pro
duce
dis
ease
or d
amag
e to
hos
t
•Vi
rule
nce:
quan
titat
ive
mea
sure
of p
atho
geni
city
•In
fect
ion:
colo
niza
tion
and
grow
th o
f mic
robe
s in
hos
t
•D
isea
se:
inju
ry o
r dam
age
of th
e ho
st
¾In
fect
ion�
Dis
ease
Can
ani
mal
s be
free
of m
icro
orga
nism
s?¾
Gno
tobi
otic
-de
scrib
es th
e co
nditi
on o
f ger
m-fr
ee in
ani
mal
s
¾G
noto
biot
ic a
nim
als
-mam
mal
s>
unbo
rn o
ffspr
ing
is re
mov
ed a
sept
ical
ly fr
om th
e st
erile
wom
b-b
irds
> ca
refu
l ste
riliz
atio
n of
the
exte
rior o
f the
egg
The
germ
-free
ani
mal
s w
ere
then
rear
ed in
a g
erm
-free
env
ironm
ent
¾C
hara
cter
istic
s of
gno
tobi
otic
ani
mal
s
> ab
norm
al a
nato
mic
al a
nd p
hysi
olog
ical
feat
ures
-und
erde
velo
ped
lym
phat
ic ti
ssue
-t
hin
inte
stin
al w
all
-low
ant
ibod
y tit
er
> hi
gher
sus
cept
ibili
ty to
pat
hoge
ns>
requ
ire n
utrit
iona
l sup
plem
ents
that
are
nor
mal
ly p
rovi
ded
by n
orm
al fl
ora
> re
duce
d su
scep
tibili
ty to
cer
tain
dis
ease
pro
cess
es d
epen
dent
on
mic
robe
se.
g. n
o de
ntal
car
ies
or p
laqu
e fo
rmat
ion
Nor
mal
flor
a¾
Ani
mal
s pr
ovid
e fa
vora
ble
envi
ronm
ents
for g
row
th o
f mic
robe
s-o
rgan
ic n
utrie
nts
and
grow
th fa
ctor
s-r
elat
ivel
y co
nsta
nt c
ondi
tions
: e.g
. pH
, osm
otic
pre
ssur
e, te
mpe
ratu
re
and
regi
ons
or o
rgan
s sh
owin
g se
lect
ive
cond
ition
s-d
ry o
r wet
(s
kin
vs.
mou
th)
-aer
obic
or a
naer
obic
(lu
ngs
vs.
gas
troin
test
inal
trac
t)-p
H
(ora
l cav
ity v
s. s
tom
ach)
¾M
ost c
omm
on s
ites
for c
olon
izat
ion:
muc
ous
mem
bran
es-r
espi
rato
ry-,
gast
roin
test
inal
-, ur
inar
y tra
ct-l
ined
with
laye
r(s)
of e
pith
elia
l cel
ls-c
oate
d w
ith la
yer o
f muc
us-d
iffer
ent t
ypes
of i
nter
actio
ns
¾N
orm
al fl
ora
prot
ects
the
host
from
col
oniz
atio
n by
pat
hoge
nic
mic
robe
s(>
bact
eria
l int
erfe
renc
e)ho
wev
eral
so n
orm
al m
icro
bes
may
bec
ome
path
ogen
ic(c
ompr
omis
ed h
ost)
Tabl
e 27
.1
Nor
mal
flor
a: S
kin
abou
t 2 m
2 of
ski
n su
rfac
e
¾un
favo
rabl
e ha
bita
t for
m
icro
orga
nism
s-m
ost a
reas
sub
ject
to p
erio
dic
dryi
ng-s
light
ly a
cidi
c pH
-hig
h so
dium
chl
orid
e co
ncen
tratio
n-1
00 to
10.
000
bact
eria
per
cm
2dr
y sk
in
¾m
ost s
kin
mic
robe
s ar
e as
soci
ated
with
sw
eat g
land
s (s
ecre
tions
con
tain
wat
er, a
min
o ac
ids,
ure
a, s
alts
and
fatty
aci
ds)
-ecc
rine
glan
dsdi
sper
sed
swea
t gla
nds
-apo
crin
e gl
ands
activ
ated
dur
ing
pube
rty: u
nder
arm
, gen
ital a
rea
etc.
> un
dera
rm o
dor d
ue to
bac
teria
l act
ivity
-seb
aceo
us g
land
s>
asso
ciat
ed w
ith h
air f
ollic
le
¾no
rmal
flor
a:S
taph
yloc
occu
s, C
oryn
ebac
teriu
m, A
cine
toba
cter
,M
icro
cocc
us, P
ropi
onib
acte
rium
, P
ityro
spor
um (y
east
)
Figu
re 2
7.2
Nor
mal
flor
a: O
ral C
avity
¾co
mpl
ex a
nd h
eter
ogen
eous
m
icro
bial
hab
itat
¾in
gest
ed fo
od a
s so
urce
of
nut
rient
s
¾to
oth
min
eral
mat
rix o
f ca
lciu
m p
hosp
hate
(ena
mel
)
¾sa
liva
(sal
ts, e
nzym
es, m
ucop
rote
ins
etc.
)
lact
oper
oxid
ase:
nat
ural
ant
ibio
tic(g
ener
ates
sin
glet
oxy
gen)
lyso
zym
e: c
leav
es g
lyco
sidi
clin
kage
s of
pep
tidog
lyca
n
lact
ofer
rin: i
ron-
bind
ing
prot
ein
(dep
rives
bac
teria
an
elem
ent
nece
ssar
y fo
r gro
wth
)Fi
gure
27.
4
Den
tal P
laqu
e¾
atta
chm
ent o
f aci
dic
glyc
opro
tein
s fr
om s
aliv
a le
ads
to th
in o
rgan
ic fi
lm
¾co
loni
zatio
n of
sm
ooth
toot
h su
rfac
edu
e to
affi
nity
to g
lyco
prot
eins
¾on
ly fe
w S
trep
toco
ccus
spp.
S. s
angu
is, S
. sob
rinus
, S. m
utan
s, S
. miti
s
S. m
utan
s pr
oduc
es d
extra
n fro
m s
ucro
se>
prod
uctio
n of
bio
film
(pla
que)
> su
bseq
uent
est
ablis
hmen
t of
-fila
men
tous
Fus
obac
teriu
msp
p.-S
piro
chet
es-g
ram
-pos
itive
rods
-gra
m-n
egat
ive
cocc
i-A
ctin
omyc
essp
p.Fi
gure
27.
6
Taub
man
Nat
ure
Rev
iew
s Im
mun
olog
y6,
555
-563
(Jul
y 20
06) |
doi
:10.
1038
/nri1
857
Mut
ans
stre
ptoc
occi
par
ticip
ate
in th
e fo
rmat
ion
of p
laqu
e on
toot
h su
rfac
es
a In
itial
atta
chm
ent o
f mut
ans
stre
ptoc
occi
to
toot
h su
rface
s as
the
first
eve
nt in
the
form
atio
n of
den
tal p
laqu
e
b A
ccum
ulat
ion
of m
utan
sst
rept
ococ
ci o
n to
oth
surfa
ce in
the
pres
ence
of s
ucro
se
c A
cid
prod
uctio
n by
mut
ans
stre
ptoc
occi
¾Th
e m
etab
olis
m o
f var
ious
sac
char
ides
(in
clud
ing
gluc
ose
and
fruct
ose)
by
the
accu
mul
ated
bac
teria
l bio
film
resu
lts in
the
prod
uctio
n an
d se
cret
ion
of c
onsi
dera
ble
amou
nts
of th
e m
etab
olic
end
-pro
duct
lact
ic
acid
, whi
ch c
an c
ause
dem
iner
aliz
atio
n of
th
e to
oth
stru
ctur
e w
hen
pres
ent i
n su
ffici
ent
amou
nts
in c
lose
pro
xim
ity to
the
toot
h su
rface
.
Den
tal C
arie
s¾
infe
ctio
us d
isea
se c
ause
d by
mic
roor
gani
sms
in p
laqu
e!
¾fe
rmen
tatio
n of
sug
ars
to la
ctic
aci
d by
lact
ic a
cid
bact
eria
> de
calc
ifica
tion
of th
e en
amel
of t
he to
oth
¾di
rect
cor
rela
tion
betw
een
S. m
utan
san
d de
ntal
car
ies
> 80
-90
% o
f all
peop
le in
US
and
Wes
tern
Eur
ope
> ne
arly
abs
ent i
n Ta
nzan
ian
child
ren
> pr
esum
ably
bec
ause
suc
rose
is a
bsen
t
NIS
HIH
AR
A&
KO
SE
KI P
erio
dont
olog
y200
0, V
ol. 3
6, 2
004,
14–
26 2
004
Gin
givi
tis a
nd P
erio
dont
itis
¾in
fect
ion
of th
e gi
ngiv
al c
revi
ce
(per
iodo
ntal
poc
ket)
¾se
vera
l “m
arke
r bac
teria
“ -A
ctin
obac
illus
act
inom
ycet
emco
mita
ns-P
orph
yrom
onas
gin
giva
lis-P
revo
tella
inte
rmed
ia-B
acte
roid
es fo
rsyt
hus
-Tre
pone
ma
dent
icol
a
¾G
ingi
vitis
>
infla
mm
atio
n of
the
gum
s du
e to
pla
que
alon
g th
e gu
mlin
e
¾Pe
riodo
ntiti
s
> lo
ssof
col
lage
n at
tach
men
t of t
he to
oth
to th
e bo
ne>
form
atio
n of
dee
p pe
riodo
ntal
poc
kets
>
bone
des
truct
ion
Bac
teria
l int
erac
tions
with
muc
ous
mem
bran
es
loos
e A
ssoc
iatio
n
Adh
esio
nIn
vasi
on to
sub
muc
osal
epith
elia
l cel
ls
Figu
re 2
7.1
Nor
mal
flor
a: G
astro
inte
stin
al T
ract
Figu
re 2
7.9
Nor
mal
flor
a: G
astro
inte
stin
al T
ract
Figu
re 2
7.9
Stom
ach
-dig
estio
n of
mac
rom
olec
ules
-sec
retio
n of
aci
d >
pH 2
-c
hem
ical
bar
rier f
or b
acte
ria
> de
void
of n
orm
al fl
ora?
Hel
icob
acte
r pyl
ori
> co
loni
zatio
n of
the
gast
ric
non-
acid
-sec
retin
g m
ucos
a-h
ydro
lyze
s ur
ea
(diff
usin
g fro
m b
lood
) >
incr
ease
in p
H-b
uffe
red
zone
aro
und
the
cells
allo
ws
colo
niza
tion
-inf
lam
mat
ion,
tiss
ue
dest
ruct
ion
and
ulce
ratio
n
Nor
mal
flor
a: G
astro
inte
stin
al T
ract
Smal
l int
estin
e¾
pH 4
-5¾
cont
inue
d di
gest
ion:
abso
rptio
n of
mon
osac
char
ides
, am
ino
acid
s, fa
tty a
cids
, wat
er
¾D
uode
num
and
Jej
unum
ar
e al
mos
t ste
rile
¾Ile
um: 1
05–
107
cells
ml-1
Larg
e in
test
ine
¾fe
rmen
tatio
n ch
ambe
r¾
1010
-101
2ce
lls g
-1
-foo
d pa
ssag
e tim
e ab
out 2
4h-g
row
th ra
te o
f lum
inal
bac
teria
:1
-2 d
oubl
ings
per
day
¾ch
emos
tate
-like
beh
avio
r due
to
con
stan
t los
s of
mat
eria
lFi
gure
27.
9
Effe
cts
of G
astro
inte
stin
al F
lora
¾be
nefic
ial e
ffect
s of
inte
stin
al m
icro
bes
> pr
ofou
nd in
fluen
ce o
n ho
st fu
nctio
n an
d w
ell-b
eing
!
-vita
min
syn
thes
is:
B12
, K, p
yrid
oxin
e, ri
bofla
vin,
thia
min
-glu
cosi
dase
act
ivity
: m
any
suga
r fer
men
ting
bact
eria
-ste
roid
met
abol
ism
:m
odifi
catio
n of
bile
aci
ds-S
CFA
pro
duct
ion:
ac
etic
, pro
pion
ic, b
utyr
ic a
cids
are
(sho
rt-ch
ain
fatty
aci
ds)
abso
rbed
and
util
ized
by
the
host
stim
ulat
e co
loni
c ep
ithel
ial c
ell p
rolif
erat
ion
¾ga
s pr
oduc
tion
(flat
us):
CO
2, H
2, C
H4
(in a
bout
1/3
of p
eopl
e)se
vera
l hun
dred
ml/d
also
N2
from
sw
allo
wed
air
¾od
orpr
oduc
tion:
H2S
, NH
3, am
ines
, ind
ole,
ska
tole
, bu
tyric
aci
d
¾in
fluen
ce o
f ant
ibio
tics
> ki
ll pa
thog
ens
buta
lso
heal
thy
mic
robe
s>
lead
s to
gas
tric
dist
ress
unt
il no
rmal
flor
a be
com
es re
esta
blis
hed
Nor
mal
flor
a: R
espi
rato
ry T
ract
¾M
ajor
sec
tions
uppe
r res
pira
tory
trac
t-S
trept
ococ
ci, S
taph
yloc
occi
, G
ram
-neg
ativ
e co
cci
-als
o pa
thog
ens:
S
trept
ococ
cus
pyog
enes
, S
trept
ococ
cus
pneu
mon
iae
Sta
phyl
ococ
cus
aure
us,
Cor
yneb
acte
rium
dip
hthe
riae
low
er re
spira
tory
trac
t-e
ssen
tially
ste
rile
¾M
odes
of p
rote
ctio
n-c
ontin
uous
upw
ard
stre
am o
f flo
win
g m
ucus
pro
duce
d by
cili
ated
cel
ls-p
rodu
ctio
n of
lyso
zym
e in
muc
us
-pha
gocy
tic a
ctio
n of
mac
roph
ages
-res
iden
t flo
ra li
mits
gro
wth
of p
atho
gens
Figu
re 2
7.11
Nor
mal
flor
a: U
roge
nita
l Tra
ct¾
Bla
dder
itse
lf us
ually
ste
rile
¾U
reth
ra>
epith
eliu
m c
olon
ized
by
facu
ltativ
e ae
robi
c gr
am-n
egat
ive
rods
and
coc
ci
-con
tain
s al
so o
ppor
tuni
stic
pat
hoge
ns: E
sche
richi
a co
li, P
rote
us m
irabi
liset
c.
-may
bec
ome
path
ogen
e.g
. due
to lo
cal c
hang
es in
pH
-b
acte
ria m
ultip
ly a
nd fr
eque
ntly
cau
se u
rinar
y in
fect
ions
¾Va
gina
adul
tsco
ntai
ns s
igni
fican
t am
ount
s of
gly
coge
n fe
rmen
ted
by L
acto
baci
llus
acid
ophi
lus
prod
uctio
n of
lact
ic a
cid Ļ
pH
befo
re p
uber
tyno
gly
coge
n sy
nthe
size
d,
no b
acte
rial n
utrit
ion
sour
ce, Ĺ
pH
afte
r men
opau
sere
turn
to g
lyco
gen-
free,
alk
alin
e en
viro
nmen
t lac
king
lact
ic a
cid
bact
eria
Doe
derle
in‘s
baci
llus
Figu
re 2
7.12
b
Viru
lenc
e¾
Abi
lity
to c
ause
dis
ease
thro
ugh
toxi
city
or i
nvas
iven
ess
¾To
xici
ty>
dise
ase
caus
ed b
y a
pref
orm
ed to
xin
that
inhi
bits
hos
t cel
l fun
ctio
n or
kill
s ho
st c
ells
-E
xoto
xins
(in
clud
ing
ente
roto
xins
)-E
ndot
oxin
� E
nter
otox
in!
¾In
vasi
vene
ss>
abili
ty to
mul
tiply
in ti
ssue
in s
uch
larg
e nu
mbe
rs th
at h
ost f
unct
ion
is in
hibi
ted
(e.g
. Stre
ptoc
occu
s pn
eum
onia
e)
Add
ition
al fe
atur
es-v
irule
nce
gene
s ar
e of
ten
clus
tere
d in
“pat
hoge
nici
ty is
land
s”-p
atho
geni
city
isla
nds
are
abse
nt in
clo
sely
rela
ted
aviru
lent
stra
ins
-man
y ba
cter
ial p
atho
gens
als
o ca
rry
viru
lenc
e ge
nes
on la
rge
plas
mid
s
How
to m
easu
re V
irule
nce?
¾Vi
rule
nce
can
be e
stim
ated
from
stu
dies
of t
he L
D50
(leth
al d
ose 5
0)
Atte
nuat
ion
> de
crea
se o
r los
sof
viru
lenc
e af
ter
labo
rato
ry c
ultu
re>
atte
nuat
ed s
train
sw
ere
ofte
n us
ed fo
r pr
oduc
tion
of v
acci
nes Fi
gure
27.
14
Wha
t are
bac
teria
l Viru
lenc
e Fa
ctor
s?¾
fact
ors
that
pro
mot
e pa
thog
enes
is:
e.g
. Sal
mon
ella
P. 8
38 F
igur
e 2
Wha
t are
the
Mec
hani
sms
of P
atho
gene
sis?
Whi
ch fa
ctor
s ar
e re
spon
sibl
e fo
r the
en
try o
f a p
atho
gen
into
hos
t?
¾Pa
thog
en m
ust h
ave
acce
ss
to h
ost t
issu
e an
d m
ultip
ly
> pe
netr
atio
n of
ski
n,
muc
ous
mem
bran
es,
inte
stin
al e
pith
eliu
mw
hich
act
as
barr
iers
Figu
re 2
7.13
Non
spec
ific
inna
te re
sist
ance
to in
fect
ion
¾A
ge, s
tres
s an
d di
etaf
fect
ove
rall
heal
th a
nd th
eref
ore
host
resi
stan
ce to
infe
ctio
ns>
YO
PI‘s
: you
ng, o
ld, p
regn
ant,
imm
uno-
com
prom
ised
peo
ple
¾Ph
ysic
al, c
hem
ical
and
ana
tom
ical
bar
riers
epid
erm
is, m
ucus
, ant
i-mic
robi
al c
ompo
unds
, low
pH
, nor
mal
flor
a
¾Ti
ssue
spe
cific
itypa
thog
ens
only
mul
tiply
in c
erta
in ti
ssue
¾C
ompr
omis
ed h
ost
> no
pro
per f
unct
ion
of o
ne o
r mor
e of
resi
stan
ce m
echa
nism
s du
e to
-illn
ess
-dru
g th
erap
y-i
njur
y-A
IDS
> co
mpr
omis
ed h
ost i
s of
ten
enco
unte
red
in a
hos
pita
l situ
atio
n:-p
roxi
mity
to d
isea
se c
arrie
rs-i
nvas
ive
proc
edur
es-n
osoc
omia
l inf
ectio
ns (i
nfec
tions
that
occ
ur in
a h
ospi
tal s
ettin
g)
Mai
n Ty
pes
of b
acte
rial E
xoto
xins
I
1.C
ytol
ytic
exo
toxi
ns:
> ac
t on
cyto
plas
mic
mem
bran
e ca
usin
g ce
ll ly
sis
Hem
olys
ins
wor
k on
var
ious
cel
ls
test
ed o
n R
BC
Leci
thin
ases
&at
tack
CM
pho
spho
lipid
s P
hosp
holip
ases
(pho
spha
tidyl
chol
ine)
Leuc
ocid
ins
wor
k on
leuk
ocyt
es
2.A
-B to
xins
: >
con
sist
of t
wo
subu
nits
A&
Bon
e bi
nds
to h
ost r
ecep
tor
seco
nd e
nter
s an
d da
mag
es th
e ce
ll
Bot
ulin
um to
xin
Clo
strid
ium
bot
ulin
umC
hole
ra to
xin
Vib
rio c
hole
rae
Dip
hthe
ria to
xin
Cor
yneb
acte
rium
dip
hthe
riae
Teta
nus
toxi
nC
lost
ridiu
m te
tani
3.Su
pera
ntig
ens:
> st
imul
ate
host
T c
ells
and
lead
to e
xten
sive
infla
mm
ator
y re
spon
se
e.g.
Sta
phyl
ococ
cus
aure
us fo
od p
oiso
ning
Stap
hylo
cocc
al E
nter
otox
ins
A -
E(in
75%
of c
ases
SE
A)
> pr
oduc
ed d
urin
g gr
owth
of S
.aur
eus
in fo
od
> he
at re
sist
ant (
10 m
in 1
00°C
)>
cook
ing
inac
tivat
es b
acte
ria b
ut n
otth
e en
tero
toxi
ns
Mod
e of
act
ion
> en
tero
toxi
ns b
ind
to T
cel
l rec
epto
r ȕ c
hain
s >
stim
ulat
e T
help
er c
ells
to c
ytok
ine
prod
uctio
n >
over
abun
danc
e of
IL-2
resp
onsi
ble
for m
ost s
ympt
oms
of g
astro
ente
ritis
Gas
troe
nter
itis
> sy
mpt
oms
deve
lop
with
in 1
to 6
hou
rs a
nd la
st 2
4 to
48
hour
s>
naus
ea, v
omiti
ng, s
ever
e ab
dom
inal
cra
mps
, dia
rrhe
a, h
eada
che
> se
lf-lim
ittin
g, m
orta
lity
rate
ver
y lo
w to
nil
Mai
n Ty
pes
of b
acte
rial E
xoto
xins
II
Ove
rvie
w o
f Im
mun
e R
espo
nse
to P
atho
gens
1
nons
peci
fic im
mun
ity
2
antib
ody-
med
iate
d im
mun
ity
3
cell-
med
iate
d im
mun
ity
Figu
re 2
9.5
from
Bro
ck 1
2/E
IL-1
IL-2
IFN-DŽ
TNF-Į
0.01
–0.
1 %
of T
-cel
l pop
ulat
ion
5 -3
0 %
of T
-cel
l pop
ulat
ion
How
do
Sup
eran
tigen
s w
ork?
A-B
Tox
ins:
Cho
lera
Tox
in
-A-B
type
toxi
n ex
erts
its
effe
ct in
sm
all i
ntes
tine
-B fr
agm
ent c
onta
ins
bind
ing
site
-A
frag
men
t act
ivat
es a
deny
l cyc
lase
(ĹcA
MP
)-c
AM
P s
timul
ates
exc
retio
n of
Cl-
and
HC
O3-
¾m
assi
ve lo
ss o
f wat
er fr
om d
iarr
hea
may
be
fata
l due
to d
ehyd
ratio
n! Figu
re 2
7.24
A-B
Tox
ins:
Bot
ulin
us T
oxin
•B
otox
= B
otul
inum
Neu
roto
xin
(BoN
T)
•se
ries
of s
even
rela
ted
A-B
toxi
ns
(two
enco
ded
on a
lyso
geni
c ph
age)
•pr
oduc
edby
Gra
m-p
ositi
ve a
naer
obic
Clo
strid
ium
botu
linum
•fo
und
in u
npro
perly
cann
ed fo
od
(end
ospo
res
germ
inat
e >
anae
robi
c gr
owth
)
•in
toxi
catio
nÆ
Bot
ulis
m
•S
ympt
oms:
cum
ulat
ive,
flac
cid
para
lysi
s (e
yes,
tong
ue, l
imbs
, res
pira
tory
arr
est)
•Le
thal
ora
l dos
e: 5
0-70ȝg
per
per
son
Æm
ostt
oxic
subs
tanc
ekn
own
1 m
g w
ould
be
suffi
cien
t to
kill
1 M
illio
n gu
inea
pig
s!
A-B
Tox
ins:
Bot
ulin
us T
oxin
BoN
T pr
even
ts re
leas
e of
ace
tylc
holin
e at
pre
-syn
aptic
mot
or n
euro
n en
d pl
ate
¾fla
ccid
par
alys
is
Figu
re 2
7.22
A-B
Tox
ins:
Te
tanu
s To
xin
-C
lost
ridiu
m te
tani
infe
ctio
n of
dee
p w
ound
s-
bind
s to
inhi
bito
ry in
tern
euro
ns a
nd b
lock
s re
leas
e of
gly
cine
-pr
even
ts re
laxa
tion
of m
uscl
e
¾sp
astic
par
alys
is
Figu
re 2
7.23