13 anaerobic bacteria

Anaerobic BacteriaAnaerobic Bacteria

An anaerobic bacteria or anaerobe is any organism that does

not require oxygen for growth. It could possibly react negatively

and may even die if oxygen is present

Overview

What is anaerobic bacteria

■ According to the tolerance to oxygen

There are three categories of anaerobic bacteria: obligate,

aerotolerant, and facultative.

▲ Obligate anaerobes (StrictlyStrictly anaerobes)： need an oxygen-free

environment to live. They cannot grow in places with oxygen,

which can sometimes damage and destroy them.

▲ Aerotolerant bacteria (moderate anaerobes)： do not use oxygen

to live, but can exist in its presence for a period of time.

▲ Facultative anaerobes use fermentation to grow in places without

oxygen, but use aerobic [e'roʊbɪk] respiration in places with

oxygen.

Classification

Spore-forming:Spore-forming: rod, gram (+) — Clostridiumrod, gram (+) — Clostridium

Nonspore-forming:Nonspore-forming:

rod, gram (+)rod, gram (+) Propionibacterium (Propionibacterium ( 丙酸杆菌属 )Bifidobacterium (Bifidobacterium ( 双歧杆菌属 )

Lactobacillus (Lactobacillus ( 乳酸杆菌 )Eubacterium (Eubacterium ( 真细菌 ) Actinomyces (Actinomyces ( 放线菌 )

rod, gram (-)rod, gram (-) Bacteroides (Bacteroides ( 类杆菌属 )Fusobacterium (Fusobacterium ( 梭菌属 )

Campylobacter (Campylobacter ( 弯曲杆菌属 )

cocci, gram (+)cocci, gram (+) Peptococcus (Peptococcus ( 消化球菌 )Peptostreptococcus (Peptostreptococcus ( 消化链球菌属 )

cocci, gram (-)cocci, gram (-) Veillonella (Veillonella ( 韦荣球菌属 )

■ According to the morphology, structure and dyeability

※ ※ The clostridia are pathogens or opportunistic pathogens. The clostridia are pathogens or opportunistic pathogens.

Nonetheless, they are responsible for some of the deadliest Nonetheless, they are responsible for some of the deadliest

diseases includingdiseases including gas gangrene, tetanus and botulism gas gangrene, tetanus and botulism. Less . Less

life-threatening diseases includelife-threatening diseases include pseudomembranous colitis pseudomembranous colitis

[kə'laɪtɪs] [kə'laɪtɪs] (PC) and food poisoning. (PC) and food poisoning.

※ ※ cause disease primarily through the production of cause disease primarily through the production of numerous numerous

exotoxins.exotoxins.

※ ※ perfringens, tetani, botulinum, difficile [ˌdɪfə'sperfringens, tetani, botulinum, difficile [ˌdɪfə'saiail]l]

Clostridium SpeciesClostridium Species

General introductionGeneral introduction

※※ C. tetaniC. tetani is found worldwide. Ubiquitous in is found worldwide. Ubiquitous in soilsoil, it is , it is

occasionally found in occasionally found in intestinal flora of humans and intestinal flora of humans and

animalsanimals

※ ※ C. C. tetanitetani is the cause of is the cause of tetanustetanus, or , or lockjawlockjaw. spores. spores

are introduced into wounds by contaminated soil are introduced into wounds by contaminated soil

or foreign objects such as nails, or foreign objects such as nails, glass splinters, glass splinters,

and so on.and so on.

C. tetaniC. tetani

※ ※ soil, fecal contaminationsoil, fecal contamination

※ ※ wound contaminationwound contamination

※ ※ gas gangrenegas gangrene

— — swelling of tissues swelling of tissues

— — gas releasegas release

C. perfringensC. perfringens

C. Botulinum

※ ※ soil, sediments of lakes, ponds, decaying vegetation.soil, sediments of lakes, ponds, decaying vegetation.

※ ※ intestinal tracts of birds, mammals and fish.intestinal tracts of birds, mammals and fish.

※ ※ botulism ['bɑːtʃəlɪzəm]botulism ['bɑːtʃəlɪzəm]

C. Tetani C. Perfringens C. Botulinum

dyeability dyeability ＆＆ morphousmorphous

GG＋＋，， slendernesslendernes

ssGG ＋＋ , tubbiness, tubbiness GG ＋＋ , tubbiness, tubbiness

sporespore

roundround ，， widwider than er than cellscells ，， terminterminal sporeal spore

ovaloval ，， subtersubterminal sporeminal spore

ovaloval ，， wider wider than cells,than cells, subterminal subterminal sporespore

flagella ＋＋－－＋＋capsulecapsule －－＋＋－－

Appearance and structure

Biological characters

Clostridium tetani : This organism is a slender bacillus forming terminal spores giving a drumstick appearance.

tennis racket-like appearance


Strictly Strictly anaerobicanaerobic; ; does not does not ferment any ferment any carbohydrate carbohydrate

and proteins.and proteins.

Moderate Moderate anaerobicanaerobic;;Blood agar:Blood agar:

Double-hemolytic zone ；；Egg-yolk agar: Egg-yolk agar: an

opaque precipitate;;Milk mediumMilk medium ：：

stormy fermen-stormy fermen-tation.tation.

Strictly anaerobicStrictly anaerobic ；；Digest meat residueDigest meat residue

and and produce stenchproduce stench. .

Ferment sugarsFerment sugars with with

production of acid production of acid

and COand CO22..

Culture characteristics

θ

α

Double-hemolytic zone




Moderate Moderate anaerobicanaerobic;;Blood agar: double Blood agar: double

zone hemolysiszone hemolysis ；；Egg-yolk agar:Egg-yolk agar: an







and COand CO22..


Growth of Clostridum perfringens on egg-yolk agar. The α-toxin

(lecithinase) hydrolyzes phospholipids in serum and egg yolk,

producing an opaque precipitate (right). This precipitate is not

observed when the organism is grown in the presence of

antibodies against the toxin (left). This reaction (Nagler's

reaction) is characteristic of C. perfringens.

['lesəθəˌneɪs] 卵磷脂酵素 ['haɪdrəˌlaɪz]

C.Tetani C.Perfringens C.Botulinum




zone hemolysiszone hemolysis ；；Egg-yolk agar: Egg-yolk agar: an







and COand CO22..


stormy fermentationstormy fermentation

C. perfringens can ferment a

variety of sugars and digest proteins.

If this anaerobic grow in milk

medium, lactose is fermented, milk is

turn acid and proteins are attacked,

producing a “stormy fermentation”

with clotting and a large amount of

gas formation.

petrolatum[ˌpetrə'leɪtəm] layer

C.Tetani C.Perfringens C. Botulinum




zone hemolysiszone hemolysis ；；Egg-yolk: Egg-yolk: an







and gas.and gas.


The spore of spore-forming clostridia can The spore of spore-forming clostridia can

tolerate boiling for tens of minutestolerate boiling for tens of minutes and they can and they can

maintainsmaintains alive for several decades in soil. alive for several decades in soil.

ResistanceResistance

▲▲ C tetani C tetani is the only species. There are no serotypesis the only species. There are no serotypes

▲ According to the antigenic of toxin, C. Botulinum can

be devided into seven types

— A, B, C, D, E, F, and G.

Types A, B and E (and occasionally F) are the principal

causes of human illness.

Classification and Antigenic TypesClassification and Antigenic Types

toxintoxin Biological FeatureBiological Feature Types of ToxinsTypes of Toxins

AA BB CC DD EE

lecithinase; increase the lecithinase; increase the

vascular permeability; vascular permeability;

hemolytic; produces hemolytic; produces

necrotizing activitynecrotizing activity

++ ++ ++ ++ ++

Necrotizing activity, induces Necrotizing activity, induces

hypertension by causing hypertension by causing

release of catecholamines release of catecholamines

[kətɪ'kəʊləmiːnz][kətɪ'kəʊləmiːnz] ..

－－ ++ ++ －－－－

increase the permeability of increase the permeability of

gastrointestinal wallgastrointestinal wall －－ ++ －－ ++ －－

Necrotizing activity; increase Necrotizing activity; increase

the vascular permeability the vascular permeability －－－－－－－－ ++

Type of C. Perfringens

Pathogenesis of tetanus caused by C tetani

Clostridium TetaniClostridium TetaniPathogenesis

['kreɪniəl] 头盖的

EpidemiologyEpidemiology ※ ※ 1 million cases of tetanus occur annually in the world, with a 1 million cases of tetanus occur annually in the world, with a

mortality rate ranging from 20% to 50%. But rare in most mortality rate ranging from 20% to 50%. But rare in most developed countries. developed countries.

※ ※ In some In some developing countries,developing countries, tetanus is still one of the ten tetanus is still one of the ten leading causes of death, and neonatal tetanus accounts for leading causes of death, and neonatal tetanus accounts for approximately one-half of the cases worldwide.approximately one-half of the cases worldwide.

※ ※ In less developed countries, approximate mortality rates In less developed countries, approximate mortality rates remain 85% for neonatal tetanus and 50% for nonneonatal remain 85% for neonatal tetanus and 50% for nonneonatal tetanus. tetanus.

※ ※ In the United States, intravenous drug abusers have become In the United States, intravenous drug abusers have become another population with an increasing incidence of clinical another population with an increasing incidence of clinical tetanustetanus

※ ※ In untreated tetanus, the fatality rate is In untreated tetanus, the fatality rate is 90%90% for the newborn for the newborn and and 40% 40% for adults.for adults.

PathogenicityPathogenicity

※ ※ No invasiveness; toxemia No invasiveness; toxemia

(exogenous infection(exogenous infection）） ※ ※ produces two exotoxins: produces two exotoxins:

tetanolysin, and tetanolysin, and

tetanospasmintetanospasmin(a kind of (a kind of

neurotoxin, strong toxicity)neurotoxin, strong toxicity)

※※ The actions of tetanospasminThe actions of tetanospasmin

are complex and involve three are complex and involve three

components of the nervous components of the nervous

system:system: central motor control, central motor control,

autonomic function, and the autonomic function, and the

neuromuscular junction.neuromuscular junction.

※ ※ retrograde transport retrograde transport

to CNS.to CNS.

※ ※ delitescence delitescence [deɪlɪ'tesns][deɪlɪ'tesns]潜潜

伏：伏：

a fewa few days to several weeksdays to several weeks

※ ※ The two animal The two animal

species most species most

susceptible to this susceptible to this

toxemia are horses toxemia are horses

and and humanshumans..

Clostridium tetaniClostridium tetani --TetanospasminTetanospasmin

※ ※ disseminates systemically disseminates systemically

※ ※ binds to ganglioside receptors binds to ganglioside receptors

※ ※ inhibitory neurones in CNSinhibitory neurones in CNS

△ △ glycine glycine

■ ■ neurotransmitterneurotransmitter

※ ※ stops nerve impulse to muscles stops nerve impulse to muscles

※ ※ spastic paralysisspastic paralysis

※ ※ severe muscle contractions and spasms severe muscle contractions and spasms

※ ※ can be fatalcan be fatal

破伤风痉挛毒素

（tetanospasmi

n）

tetanospasmin

Motorial end Lymph,blood

Retrograde transport Spinal anterior cell

Brain stem

TetanospasminTetanospasmin

Henvy chain

Light chain Release of transmitters

['vesɪkl]

TetanospasminTetanospasmin

Extensor

Flexor

＋

＋②

①①＋

③

－

① ： motor neuron② ： inhibitory interneuron③ ： Renshaw cells＋： stimulate －： inhibit： Toxin site

Clinical ManifestationsClinical Manifestations

※ ※ The initial symptom is cramping and The initial symptom is cramping and

twitching of muscles around a wound. twitching of muscles around a wound.

The patient usually has The patient usually has no feverno fever but but

sweats profusely and begins to sweats profusely and begins to

experience pain, especially in the area of experience pain, especially in the area of

the wound and around the neck and jaw the wound and around the neck and jaw

muscles muscles (trismus ['trɪzməs](trismus ['trɪzməs]牙关紧闭症牙关紧闭症 ).).

※ ※ Portions of the body may Portions of the body may

become extremely rigid, become extremely rigid,

and and opisthotonos opisthotonos

[əʊ'pɪsθəʊtənəʊz][əʊ'pɪsθəʊtənəʊz] 角弓反张 (a (a

spasm spasm

in which the head and heels in which the head and heels

are bent backward and the are bent backward and the

body bowed[boʊd] forward) is body bowed[boʊd] forward) is

common.common. ※ ※ Complications include fractures, bowel impaction, Complications include fractures, bowel impaction,

intramuscular hematoma, muscle ruptures, and intramuscular hematoma, muscle ruptures, and

pulmonary, renal, and cardiac problemspulmonary, renal, and cardiac problems

ImmunityImmunity

※ ※ Humoral immunityHumoral immunity(antitoxin)(antitoxin)

※ ※ There is little, if any, inate immunity and the There is little, if any, inate immunity and the

disease does not produce immunity in the patient. disease does not produce immunity in the patient.

※ ※ Active immunity follows vaccination with tetanus Active immunity follows vaccination with tetanus

toxoidtoxoid

DiagnosisDiagnosis

※ ※ Diagnosis is primarily by Diagnosis is primarily by the clinical symptoms (above). the clinical symptoms (above). The The

wound may not be obvious. wound may not be obvious.

※ ※ C. tetani can be recovered from the wound in only about C. tetani can be recovered from the wound in only about

one-third of the cases.one-third of the cases.

※ ※ It is important for the clinician to be aware that toxigenic It is important for the clinician to be aware that toxigenic

strains of C. tetani can grow actively in the wound of an strains of C. tetani can grow actively in the wound of an

immunized person.immunized person.

※ ※ Numerous syndromes, includingNumerous syndromes, including rabies and meningitis, rabies and meningitis, have have

symptoms similar to those of tetanus and must be symptoms similar to those of tetanus and must be

considered in the differential diagnosis.considered in the differential diagnosis.

VaccinationVaccination

※ ※ infantinfant

※ ※ DPT (diptheria, pertussis, tetanus)DPT (diptheria, pertussis, tetanus)

※ ※ tetanus toxoid tetanus toxoid

— — antigenicantigenic

— — no exotoxic activityno exotoxic activity

※ ※ The offending organism must be removed by local The offending organism must be removed by local

debridementdebridement清创术清创术

※ ※ toxoid toxoid

※ ※ TATTAT; Metronidazole [ˌmetrə'naɪdəˌzoʊl]; Metronidazole [ˌmetrə'naɪdəˌzoʊl] 灭滴灵灭滴灵

(For more serious wounds)(For more serious wounds)

※ ※ AIDS AIDS patients may not respond to prophylactic patients may not respond to prophylactic

[ˌproʊfə'læktɪk][ˌproʊfə'læktɪk] injections of tetanus toxoidinjections of tetanus toxoid

ControlControl

EpidemiologyEpidemiology

※ ※ C. perfringensC. perfringens type A: type A: the intestinal tract of humans and the intestinal tract of humans and

animals, soil and water contaminated with feces. Forms animals, soil and water contaminated with feces. Forms

spores under adverse environmental conditions and can spores under adverse environmental conditions and can

survive for prolonged periods.survive for prolonged periods.

※ ※ Type B to E strainsType B to E strains colonize the intestinal tract of animals colonize the intestinal tract of animals

and occasionally humans.and occasionally humans.

Pathogensis of C. Perfringens


※ ※ Type AType A: gas gangrene, soft tissue infections and food poisoning: gas gangrene, soft tissue infections and food poisoning

※ ※ Type CType C: enteritis; necroticans: enteritis; necroticans


Who is at risk?Who is at risk?

※ ※ Surgical patients;Surgical patients; patient after trauma with soil patient after trauma with soil

contamination.contamination.

※ ※ People who ingest contaminated People who ingest contaminated meat productsmeat products (without (without

proper refrigeration or reheating to inactivate endotoxin)proper refrigeration or reheating to inactivate endotoxin)


ToxinsToxins

※ ※ Many toxins of Many toxins of C. Perfringens have lethal, necrotizing, have lethal, necrotizing,

and and

hemolytic properties;hemolytic properties;

※ ※ The alpha toxin produced by all types of The alpha toxin produced by all types of C. perfringens,C. perfringens, it is it is

a lecithinase that lyses erythrocytes, platelets, leukocytes, and a lecithinase that lyses erythrocytes, platelets, leukocytes, and

endothelial cells. And its lethal action is proportionate to the endothelial cells. And its lethal action is proportionate to the

rate at which it splits lecithin to phosphorylcholine rate at which it splits lecithin to phosphorylcholine

[fɒsfərɪl'koʊlɪn][fɒsfərɪl'koʊlɪn] and diglyceride [daɪ'glɪsəˌraɪd]and diglyceride [daɪ'glɪsəˌraɪd]甘油二酯甘油二酯 ..

※ ※ The theta toxin has similar hemolytic and necrotizing effects.The theta toxin has similar hemolytic and necrotizing effects.

※ ※ DNAase, hyaluronidase[ˌhaɪəlʊ'rɒnɪˌdeɪs], collagenase are DNAase, hyaluronidase[ˌhaɪəlʊ'rɒnɪˌdeɪs], collagenase are

also producedalso produced


EnterotoxinEnterotoxin

※ ※ Many strains of type A produce enterotoxin, which is a heat-Many strains of type A produce enterotoxin, which is a heat-

labile ['leɪbəl]labile ['leɪbəl]易变的易变的 protein and destroyed immediately at 100 protein and destroyed immediately at 100

.℃.℃

※ ※ Trypsin treatment enhances the toxin activity threefold.Trypsin treatment enhances the toxin activity threefold.

※ ※ The toxin is produced primarily by type A strains but also by The toxin is produced primarily by type A strains but also by

a few of type C and D strains.a few of type C and D strains.

※ ※ It disrupts ion transport in the ileum['ɪliəm]It disrupts ion transport in the ileum['ɪliəm] 回肠回肠 (primarily) and (primarily) and

jejunum [dʒɪ'dʒuːnəm]jejunum [dʒɪ'dʒuːnəm] 空肠空肠 by inserting into the cell membrane by inserting into the cell membrane

and altering membraneand altering membrane permeability. permeability.

※ ※ As superantigen.As superantigen.


※ ※ Tissue degrading enzymes Tissue degrading enzymes

— — lecithinaselecithinase

— — proteolytic enzymesproteolytic enzymes

— — saccharolytic [sækərə'lɪtɪk]saccharolytic [sækərə'lɪtɪk] 糖分解的糖分解的 enzymesenzymes

※ ※ Destruction of blood vessels Destruction of blood vessels

※ ※ Tissue necrosisTissue necrosis

※ ※ Anaerobic environment created Anaerobic environment created

※ ※ Organism spreadsOrganism spreads


Without treatment death Without treatment death occurs within 2 daysoccurs within 2 days effective antibiotic therapyeffective antibiotic therapy debridement debridement anti-toxinanti-toxin amputation & death is rareamputation & death is rare

Gas gangreneGas gangrene

※ ※ Gas gangreneGas gangrene is a life-threatening disease with a poor is a life-threatening disease with a poor

prognosis and often fatal outcome. prognosis and often fatal outcome.

※ ※ Initial trauma to host tissue damages muscle and impairs Initial trauma to host tissue damages muscle and impairs

blood supply —— lack of oxygenation blood supply —— lack of oxygenation

※ ※ Initial symptoms Initial symptoms : : fever fever and pain in the infected tissue; and pain in the infected tissue;

more local tissue necrosis and systemic toxemia. Infected more local tissue necrosis and systemic toxemia. Infected

muscle is discolored (purple mottling ['mɒtlɪŋ]muscle is discolored (purple mottling ['mɒtlɪŋ] 斑点斑点 ) and ) and

edematous andedematous and produces a produces a foulfoul-smelling exudate; gas -smelling exudate; gas

bubblesbubbles form from form from the products of anaerobic fermentation.the products of anaerobic fermentation.

Gas gangreneGas gangrene

※ ※ As capillary permeability increases, the accumulation of As capillary permeability increases, the accumulation of

fluid increases, and venous return eventually is curtailed. fluid increases, and venous return eventually is curtailed.

※ ※ As more tissue becomes involved, the clostridia multiply As more tissue becomes involved, the clostridia multiply

within the increasing area of dead tissue, releasing more within the increasing area of dead tissue, releasing more

toxins into the local tissue and the systemic circulation.toxins into the local tissue and the systemic circulation.

painpainful, black, ful, black, edematous andedematous and foulfoul

Food poisoningFood poisoning

※ ※ Enterotoxin producing strains.Enterotoxin producing strains.

※ ※ These bacteria are found in mammalian These bacteria are found in mammalian faeces and soil.faeces and soil.

※ ※ Small numbers of the bacteria may also be found in foods Small numbers of the bacteria may also be found in foods

and they may propagate rapidly to dangerous and they may propagate rapidly to dangerous

concentrations if the food is improperly stored and concentrations if the food is improperly stored and

handled.handled.

Food poisoningFood poisoning

※ ※ more than 10more than 1088 vegetative cells are ingested and sporulate in vegetative cells are ingested and sporulate in

the gut, the toxins can act rapidly in the body, causing the gut, the toxins can act rapidly in the body, causing

severe diarrhea in 6severe diarrhea in 6～～ 18 hours, dysentery, gangrene, 18 hours, dysentery, gangrene,

muscle muscle

infections infections

※ ※ The action of The action of C. perfringensC. perfringens enterotoxin involves marked enterotoxin involves marked

hypersecretion in the jejunum and ileum, with loss of fluids hypersecretion in the jejunum and ileum, with loss of fluids

and electrolytes in diarrhea.and electrolytes in diarrhea.

Cellulitis, FasciitisCellulitis, Fasciitis

※ ※ Fasciitis [ˌfæʃi'aɪtɪs]Fasciitis [ˌfæʃi'aɪtɪs] 筋膜炎筋膜炎 : a rapidly progressive, : a rapidly progressive,

destructive process in which the organisms spread destructive process in which the organisms spread

through fascial planes.through fascial planes.

※ ※ Fasciitis causes suppuration and the formation of gasFasciitis causes suppuration and the formation of gas

※ ※ Absense of muscle involvementAbsense of muscle involvement

※ ※ rapidityrapidity

Clostridial anaerobiccellulitis: following acompound fracture ofthe tibia ['tɪbiə] 胫节 . Crepitus [k'repɪtəs] 捻发音was noted on examand the presence ofgas confirmedradiologically.

Postoperative [ po st' p r t v]ˌ ʊ ɒ ə ə ɪ 手术后的 gangrenous cellulitis: a huge area of ulceration filled with gangrenous skin and slough[sla ]ʊ 腐肉 lies adjacent to the wound. There is surroundingcellulitis and a further area of necrotic skin in the flank [flæ k]ŋ 侧面 .

※ ※ Rare, acute necrotizing process in the jejunumRare, acute necrotizing process in the jejunum

※ ※ Abdominal pain, bloody diarrhea, shock, and peritonitisAbdominal pain, bloody diarrhea, shock, and peritonitis

※ ※ Mortality: 50%Mortality: 50%

※ ※ Beta-toxin-producing Beta-toxin-producing C. perfringensC. perfringens type C type C

※ ※ SepticemiaSepticemia

Necrotizing EnteritisNecrotizing Enteritis

Small intestinal serosal [sɪ'roʊsə] 浆膜 surfaces are diffusely red

Small intestinal contents are red and watery

UP

C. botulinumC. botulinum

— spores heat resistant. canning. anaerobic environment — Botulism eating uncooked foods spores— GI, duodenum[ˌduːə'diːnəm]十二指肠 , blood stream, neuromuscular synapses.

TransmissionTransmission

— bacterial protease

— light chain, A, 50 kDa;

heavy chain, 100kDa.

— disulfide bond.

— A potent toxin

Virulence factorsVirulence factors

▲ ▲ binds peripheral nerve receptorsbinds peripheral nerve receptors

△ △acetylcholine neurotransmitteracetylcholine neurotransmitter

▲ ▲ inhibits nerve impulses inhibits nerve impulses

▲ ▲ flaccid paralysisflaccid paralysis

▲ ▲ death death

△ △ respiratory respiratory

△ △ cardiac failurecardiac failure

['mʌskjələtʃər] 肌肉组织

Botulinum toxinBotulinum toxin

※ ※ BioterrorismBioterrorism

△ △ not an infectionnot an infection

△ △ resembles a chemical attack resembles a chemical attack

△ △ 10 ng can kill a normal adult10 ng can kill a normal adult

---foodborne, infant, wound, undetermined. ---Certain foods; wound not.---Foodborne botulism, consumption.---Infant botulism, 1976, under 12m. ---ingestion, colonize and produce toxin in the intestinal tract of infants. ---increased.---internationally recognized.


— 18-36 hours:

— weakness, dizziness,dryness of the mouth.

— Nausea,vomiting.

— Neurologic features

△ blurred vision

△ inability to swallow

△ difficulty in speech

△ descending weakness of skeletal ['skelətl]

骨骼的muscles

△ respiratory paralysis.

Clinical syndromesClinical syndromes

BotulismBotulism

▲ ▲ food poisoningfood poisoning

△ △ rarerare

△ △ fatalfatal

▲ ▲ germination of spore germination of spore

▲ ▲ inadequately sterilized canned food inadequately sterilized canned food

△ △ homehome

△ △ not an infectionnot an infection

Infection with Infection with C. botulinumC. botulinum

※ ※ Neonatal botulismNeonatal botulism

▲ ▲ uncommonuncommon

▲ ▲ the predominant form of botulismthe predominant form of botulism

▲ ▲ colonization occurscolonization occurs

△ △ no normal flora to competeno normal flora to compete

△ △ unlike adultunlike adult

WoundsWounds

※ ※ extremely rareextremely rare

※ ※ an infectionan infection

— — specifically neutralized, specifically neutralized, antitoxin.antitoxin.

— — toxoided, make good antigens.toxoided, make good antigens.

— — does not develop, amount toxic. does not develop, amount toxic.

— — Repeated occurrence. Repeated occurrence.

— — Once bound, unaffected by antitoxin.Once bound, unaffected by antitoxin.

— — circulating toxin ,circulating toxin , neutralized , injection of neutralized , injection of

antitoxin.antitoxin.

— — treated immediately with antiserum. treated immediately with antiserum.

— — multivalentmultivalent toxoid,unjustified,infrequency. toxoid,unjustified,infrequency.

experimental vaccine.experimental vaccine.

ImmunityImmunity

TREATMENT

• Individuals known to have ingested food with botulism should be treated immediately with antiserum. • antibiotic therapy (if infection)• Vaccination will not protect hosts from botulism, however passive

immunisation with antibody is the treatment of choice for cases of botulism.

PREVENTION

---proper food handling and preparation.

--- spores survive boiling (100 degrees at 1 atm) 1h.

---toxin heat-labile, boiling or intense heating, inactivate the toxin.

---bulge[bʌldʒ]膨胀 , gas, spoiled.

Exercises:

Anaerobic bacteria (anaerobe) Stormy fermen-tation

Nagler reaction TAT(tetanus antitoxin)

1. Briefly describe the pathogenic conditions and mechanism of C. Tetani.

2. Briefly describe the principle of the treatment and prevention of tetanus,

3. Please briefly describe the pathogenic mechanism of Botulinum toxin.

13 anaerobic bacteria

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Transcript of 13 anaerobic bacteria