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Bacteriology > Lab 2. Bacillus anthracis, aerobic spore-forming bacteria. Clostridium > Flashcards

Lab 2. Bacillus anthracis, aerobic spore-forming bacteria. Clostridium Flashcards

1
Q

genus Bacillus:

  • key points
A
  • the genus comprise more than 330 species
  • large, Gram + rods, up to 10um in length
  • endospores are produced
  • obligate aerobic or facultative anaerobic
  • catalase +, oxidase -
  • motile
  • most species are saprophytes
  • Habitat: widely distributeed in the environment, soil (highly resistant endospores)
  • B. anthrasis is the most important pathogen
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2
Q

Bacillus species:

A
  • B. anthracis
  • B. cereus:

–> cattle: mastitis (rare)

–> humans: food poisoning (reheated fried rice), eye infections

  • B. licheniformis: cattle sheep: sporadic abortion
  • Paenibacillus larvae: Americal foulbroud of honey bees
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3
Q

Bacillus anthracis:

  • habitat, morphology, staining
A

Habitat:

  • animals (vegetative), environemtn (spore)

Morphology:

  • 4-5 um rod, central spore, capsule, no flagella
  • in microscope you can se: chains of square-ended, spore-forming rods, long chains

Staining:

  • Gram +, toludine-blue
  • metachromatic staining: capsule is pink, bacteria is blue
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4
Q

Bacillus anthracis:

  • culture, biockemistry, antigens
A

Culture:

  • simple (nutrient broth or agar, blood agar, air, 37*C)
  • R-S colonies (depends on CO2)
  • Capsule: Poly-D-glutamic acid (virulence factor - inhibits phagocytosis), plasmid encoded
  • Spore - for spore formation: at least 15*C, water, O2, cations are needed
  • DO NOT OPEN THE CARCASS
  • Time needed: 37*C: finished within 16 hours. 18*C: it will start after 50 hours

Biochemistry:

  • active metabolism, catalase +, oxidase -

Antigens:

  • Capsule: poly-D-glutamic acid
  • Polysaccharide hapten: cell wall heat stabile, ascoli test, B. cereus - cross reaction!
  • Toxin (plasmid encoded):

–> oedema factor

–> lethal factor

–> protective antigen

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5
Q

Bacillus anthracis:

  • resistance, pathogenicity
A

Resistance:

  • vegetative vbacterium: several days in a carcass, skin: 2 weeks, bone marrow: 4 weeks, 56*C: 15min
  • Spore: in the soil it can survive for more than 50 years, boiling: 5-10 min, formalin (8-10%): 12-24 hr

Pathogenicity: mammals, mainly herbivores

  • cattle, sheep: fatal peracute or acute septicaemic anthrax
  • pigs: subacute anthrax with oedematous swelling in pharyngeal region
  • horses: subacute anthrax with localised oedema, septicaemia with colic and enteritis
  • humans: skin-, pulmonary and intestinal forms
  • carnivores: are comparatively resistant
  • birds: totally resistant
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6
Q

Paenibacillus larvae

A
  • Larvae up to 3 days old become infected by ingesting spores that are present in their food. - Young larvae less than 24 hours old are most susceptible to infection.
  • Spores germinate in the gut of the larva and the vegetative form of the bacteria begins to grow, taking its nourishment from the larva.
  • Spores will not germinate in larvae over 3 days old.
  • Infected larvae normally die after their cell is sealed.
  • The vegetative form of the bacterium will die but not before it produces many millions of spores.
  • Each dead larva may contain as many as 100 million spores.
  • Infected larvae darken and die.
  • infcted beehives must be burned!
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7
Q

Saprophyte Bacilli:

A
  • B. subtilis
  • B. megaterium
  • B. cereus
  • B. licheniformis/subtilis: bacitracin
  • B. thuringiensis: insect pathogen, pest-control
  • Paenibacillus (B.) polymyxa: polymyxins
  • Geobacillus (B.) stearothermophilus: heat resistant test organism
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8
Q

Differentiation of the most important Bacillus sp

A
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9
Q

genus Clostridium

  • Key points
A
  • more than 230 species
  • large Gram +, rods
  • endospores produced
  • obligate anaerobic
  • catalase - and oxidase -
  • motile (except C. perfringens
  • enriched media are required
  • present in soil, in alimentary tract of animals and in faeces
  • pathogens can be grouped according to the mode and sites of action of their potent exotoxins:

–> neurotoxic clostridia

–> histotoxic clostridia

–> enteropathogenic and enterotoxaemia producing clostridia

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10
Q

Clostridium

  • habitat, morphology, staining, culture
A

Habitat:

  • soil, mud, water, gut

Morphology:

  • 7-80 um rod, flagella (except C. perfr!)
  • spore (terminal, subterminal, central),
  • no capsule (except C. perfr!)

Staining: Gram+

Culture:

  • anaerobic,
  • oxygen tolerance is different: C. tetani, C. novyi B is strick anaerobic!. While C. histolyticum, C.botulinum can tolerate O2.
  • nutrient agar, blood agar
  • optimal temperature: 37*C, 40-45*C for C.perfringens, 15-22*C for C.putrefaciens
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11
Q

Clostridium

  • biochemistry, antigens, resistance
A

Biochemistry:

  • catalase -, oxidase-, OF: fermentative
  • active metabolism, carbohydrates are fermented (exc: C.tetani, C.histolyticum)
  • exotoxins: toxin, toxoid or anatoxin, antitoxin

Antigens:

  • complex, close relationship

Resistance:

  • vegetative (like Gram+)
  • spore (in dry specimens; for years; C. botulinum: 3-4hr boiling)

–> C. perfr. spore: 5-10 min boiling, 8% formalin: 2hr

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12
Q

Pathogenic Clostridium species overwiev:

A
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13
Q

Clostridium

  • Gas gangrenic diseases
A

malignant oedema (cattle, pig, sheep)

•C. septicum

  • C. novyi
  • C. haemolyticum
  • C. histolyticum
  • C. sordellii

Blackleg (cattle, sheep)

•C. chauvoei

human gas gangrene

  • C. perfringens A
  • C. novyi A
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14
Q

Clostridium

  • enterotoxemic diseases
A
  • necrotic enteritis of chicken: C. perfringens A/C
  • lamb dysentery: C. perfringens B
  • necrotic enteritis of pigs, struck of sheep: C. perfringens C
  • pulpy kidney disease of sheep: C. perfringens D
  • ulcerative enteritis of chicken: C. colinum
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15
Q

Clostridium

  • intoxications
A
  • tetanus: C. tetani
  • botulism: C. botulinum
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16
Q

C. septicum

A
  • culture: nutrient agar
  • toxins: alpha (haemolytic, necrotic, lethal), DN-ase, hialuronidase, haemolysin)

• disease: malignant oedema in cattle pig and sheep bradsot (abomasitis in sheep and calves, braxy)

17
Q

C. novyi

A
  • toxins: alpha, lipase, lecitinase, DN-ase, collagenase
  • types: A, B, C (non pathogenic, no toxins)
  • diseases:
  • gas gangrene: Cl. novyi A/B
  • infectious necrotic hepatitis of sheep (and cattle): Cl. novyi B
18
Q

C. haemolyticum

A

•bacillary haemoglobinuria of cattle (and sheep)

19
Q

C. histolyticum

A
  • wide spread, can tolarate O2
  • toxins: alpha, collagenase, protease, elastase, haemolysin

•Disease: malignant oedema cattle, pig, sheep

20
Q

C. chauvoei

A
  • culture: blood agar, strong haemolysis, only guinea-pig suscept.! •toxins: as C. septicum
  • disease: blackleg in cattle and sheep
  • differentiation from C. septicum: culture, IF, animal trial, toxin neutralisation
21
Q

C. perfringens

A
  • optimal temperature: 40- 45 oC, no flagella, have a capsule
  • toxins:
  • main (alpha, beta, epsilon, iota – activated by trypsin)
  • auxiliary toxins (gamma, delta, theta, kappa, lambda, mü), neutralisation
22
Q

C. colinum

A

quail, chicken, turkey, pheasant: ulcerative enteritis: intestinal ulceration, hepatic necrosis

23
Q

C. difficile

A

enterotoxin, cytotoxin

human: pseudomembranaceus colitis
foal: haemorrhagic enterocolitis in newborn foals
dog: chronic diarrhoea

24
Q

C. tetani

A
  • strict anaerobic
  • ten serotypes (flagella Atg) – same toxin effect

• toxins:

  • neurotoxin (tetanospasmin: split synaptobrevin in inhibitory nerve, inhibit the release of neurotransmitters, rigid paralysis)
  • haemolysin
  • fibrinolysin

• disease: tetanus
(horse, man: highly susceptible,
ruminants and pigs: moderately susceptible, carnivores are comparatively resistant, poultry are not susceptible)

25
Q

C. botulinum

A

biochemically not uniform

A-B-C-D-E-F-G toxintypes

ABEF: soil, activated by trypsin – human disease

CD: soil, intestine – disease in animals

toxins: heat stabile, split synaptobrevin in neuromuscular junctions, inhibit the release of acetyl-cholin in neuromuscular synapsis, flaccid paralysis

1 mg toxin: 30 000 000 mice LD50

26
Q

C. piliforme

A
  • systematic position questionable
  • culture: mouse fibroblast, liver, embryonated egg

• disease: Tyzzer’s disease (dog, cat, foal, rabbit)

Bacteriology (10 decks)

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