Lecture

17Human-Microbe

InteractionsIntimate

strangers:

Microanisms

in

and

on

usSchool

of

Life

Science

and

TechnologyShanghai

Jiao

Tong

UniversityChapter

21

inBROCK

BIOLOGY

OF

MICROANISMSI.BENEFICIAL

MICROBIAL

INTERACTIONS

WITHHUMANS對

有益的微生物Overview

of

Human-Microbial

InteractionsNormal

flora正常微生物區系Micro anisms

that

are

usually

found

associated

with

healthybody

tissueIntimate,

beneficial

and

sometimes

essential

relationships與人關系:緊密,有益,有時是必需的Parasites寄生物

anisms

that

live

on

or

in

another

host anism,

impartingno

benefits

to

thehostPathogens病源物Parasites

that

causes

damages

to

the

host造成寄主寄生物的Virulence:The tative

measure

of

pathogenicity毒力:致病能力的數值化測定Infection:

any

situation

in

which

a

micro anism

isestablished

and

growing

in

a

host,

whether

or

not

the

hostis

harmed.Infection

is

not

synonymous

with

disease.病不等同于疾Shanghai

Jiao

Tong

UniversityHost-Parasite

InteractionsFigure:21-01

Bacterial

interactions

with

mucous

membranes微生物與粘膜的互作.(a)

Loose

association.(b)

Adhesion.(c)

Invasion

intosubmucousalepithelial

cells侵入上皮細胞.Normal

flora

of

human

host

正常菌群?Skin

皮膚?Oral

口腔?Gastrointestinal

tract胃腸道?Respiratory

tract呼吸道?Urogenital

tract泌Shanghai

Jiao

Tong

University17.2

Normal

flora

of

the

skin2

m2

skin

surface

with

periodic

drying.

The

skin

surface(epidermis)

is

not

a

favorable

place

for

microbial

growth.Sweat

glands:

most

skin

micro anisms

are

associateddirectly

or

indirectly

with

it.多數皮膚微生物與汗腺有關腺腺Eccrine

glands外Apocrine

glands頂Sebaceous

glands脂肪Underarm

odor腺Develops

as

a

result

of

bacterial

activity

in

the

apocrinesecretions;狐臭由頂 腺的微生物產生Figure:

21-02

The

human

skin.

Micro anisms

are

associatedprimarily

with

the

sweat

ducts

and

the

hair

follicles.腺管毛囊表皮真皮皮下組織皮脂腺Transient

flora臨時菌群The

skin

is

continually

being

inoculated

with

transientmicro anisms,

which

are

unable

to

multiply

and

usually

die.Resident

flora聚居菌群Able

to

multiply,

not

merely

survive.Gram-positive

bacteria

(primary

constituents)Staphylococcus葡萄球菌Corynebacterium棒桿菌Propionibacterium

acnes痤瘡丙酸桿菌–acneGram

negative

bacteria

(minor

constituents)Acinetobacter不動桿菌Normal

flora

of

the

skinFactors

that

affect

the

nature

and

extent

of

the

skin

normalfloraWeather:

affect

the

skin

temperature

and

moisture.Age:

children

have

a

more

varied

microfloraal

hygiene:Shanghai

Jiao

Tong

University17.3

Normal

flora

of

the

oralOral

contains

a

complex

and

heterogeneousmicrobial

habitat.口腔微生物復雜而多樣化Saliva:Contains

very

few

nutrients

and

a

number

ofantibacterial

substance唾液Lysozyme-cell

wall

weakening溶菌酶Lactoperoxidase-singlet

oxygen

formation乳過氧化物酶The

toothMineral

matrix

of

calcium

phosphate琺瑯質牙本質牙齦縫牙髓質齒齦牙槽骨牙周膜骨髓Fig

21.317.3.1

Dental

plaque

formation

牙斑The

bacterial

conolization

occurs

as

a

result

of

atta

entof

single

bacterial

cells,followed

by

growth

of

microcolonies.單個細菌定植,并形成微菌落Form

a

thin anic

film

by

the

atta ent

of

acidic

glycoproteinsfrom

the

saliva

細菌與酸性糖蛋白結合形成一薄層膜Colonization

of

Streptococcus

onto

the

film

to

form

a

thickbacterial

zone-theplaque鏈球菌在有機物膜上形成菌膜:牙斑Filamentous

Fusobacterium,

spirochetes

Borrelia,

G+

rods

and

G-cocci

follow

in

heavyplaque絲狀梭桿菌,

螺旋體,

G+桿菌,G-球菌形成厚的牙斑Dental

plaque

developmentbrushedunbrushedDistribution

of

dentalplaqueon

brushed

(top)and

unbrushed

(bottom)teeth.Thenumbers

give

the

totalarea

of

dental

plaque.

Thered

areas

indicate

plaque.17.3.2

Dental

caries

(tooth

decay)駐牙The

tooth

crevices

retain

food

particles

(dogs

are

highlyresistant

to

tooth

decay

because

the

sh

of

theirteethdoes

not

favor

retention

of

food)Acid

products

from

dental

plaque

decay

the

tooth:

Lacticacid

bacteria

ferment

sugar

into

lactic

acid

which

causesdecalcificationoftheenamel牙斑的酸性產物腐蝕牙齒:乳酸菌發酵糖而產生乳酸,乳酸導致琺瑯質脫鈣Incorporation

of

fluoride

into

the

mineral

matrix

makes

enamelmore

resistantto

decalcification氟化物:增加對脫鈣作用的抵抗力17.4

Normal

flora

of

the

gastrointestinal

tract胃腸道正常菌群食道十二指腸空腸回腸結腸Fig

21.8

human

gastrointestinal

tract

showing

the

distribution

of

nonpathogenicmicro anisms

usually

found

in

normal

individuals胃腸道中正常微生物分布StomachAbout

pH2.The

bacterial

count

is

generally

very

low.細菌數量很低Helicobacter

pylori

can

colonize

thestomach

wall,

resulting

in

ulcers幽門螺桿菌定殖于胃壁,造成潰瘍.Small

intestineSeparated

into

the

duodenum

and

the

ileum,withthejejunumconnectingthem.小腸由十二指腸、空腸和回腸組成.Duodenum:fairly

acidic

and

resembles

thestomach

in

its

lack

of

a

microbial

flora.十二指腸酸性大,與胃一樣缺少微生物菌群Lower

ileum:Cell

number

is

105-107cells/gram

回腸后段微生物數量增加Large

intestineCecum盲腸+colon結腸Colon:bacteria

are

present

in

large

numbers,400species

identified,cell

number:1010-1011

cells/gram結腸中有大量細菌,可有400多個種The

facultative

aerobes

consume

any

oxygenpresent,making

the

environment

strictly

anaerobicand

favorable

for

the

growth

of

obligate

anaerobes.兼性好氧菌消耗所有氧,環境變為嚴格厭氧,嚴格厭氧菌大量生長Functions

of

the

intestinal

floraSteroid

metabolism

Vitamin

synthesis

Gas

production

Odor

productionanic

acid

productionGlycosidase

reactionsTable

21.217.5

Normal

flora