Lecture 16: Bacillus and Clostridium 1 Flashcards by Jen McGann

Are Bacillus spp gram positive or negative and what shape

Gram positive rods

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Are Bacillus spp spore forming and are they bulging or non-bulging

Spore forming, non-bulging

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Where are Bacillus spp found

Soils, decaying organic material, water, human microbiota

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Bacitracin is produced by what bacillus spp

B. Licheniformis

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Polymixin B is formed by what bacillus spp

B. Poylmyxa

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Bt toxin is formed by what Bacillus spp

B. Thurinfinesis

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What the results of Bacillus spp for catalase and oxidase tests

Catalase positive, oxidase negative

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what does B. Licheniformis cause in sheep and cattle

Sporadic abortions

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What does B. Cereus cause in cattle

Abortions and mastitis- acutely fatal or loss of udder quadrant

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What does B. Subtilis cause in cattle

Mastitis and abortions

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What does the core structure of endospores contain

DNA, ribosomes, lower h20 content

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What is the endospore germ cell wall made of

Peptidohylcan

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What does the cortex of endospore contain

Less rigid peptidoglycan, 1/2 spore volume

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What does the coat of endospore contain

Heavily crosslinked proteins

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Identify which is Clostridal spp and which is Bacillus spp. how do you know

left: clostridial- bulging endospores
Right: Bacillus- non-bulging endospores

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What is the infectious agent in B. Anthracis

QSpores

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B. Anthracis is a CDC category ___ pathogen

Category A priority pathogen

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What is the unique part of B. Anthracis cell wall

Secondary cell wall polysaccharide that is covalently bound to peptidoglycan

Anchors S layer to peptidoglycan

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What is the S- layer

Surface proteins on B. Anthracis cell wall

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What is the Sap protein of S layer

Primary protein during exponential growth

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What is the EA1 protein in B. Anthracis S layer

Replaces Sap as cell enters stationary growth phase

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What component of the S layer is a strong target for vaccines

EA1 protein

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Not all B. Anthracis strains are virulent, what do they carry to become virulent

Two extra chromosomal plasmids

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What are the two extra chromosomal plasmids of B. Anthracis

PXO1
PXO2

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What does PXO1 encode for

1. Lethal factor (LF) 2. Edema Factor (EF) 3. Protective antigen (PA)- binds EF and LF

what does LF +PA toxin in B. Anthracis do

Cleaves host cell MAP kinase proteins leads to host cell death and releases of TNFalpha

What does EF +PA toxin in B. Anthracis do

Increases cAMP levels in host cell, leads to swelling and edema

What does the PXO2 toxin in B. Anthracis encode for

Capsule production. - caPBCDAE Oberon encodes genes necessary for poly-y-D-glutamic acid capsule - inhibits phagocytosis

What are the routes of infection for B. Anthracis

1. Inoculation via exposed skin 2. Ingestion 3. Inhalation- likely bioterrorism route, 50% fatal once symptoms arise

What does B. Anthracis do in sheep, goats, and cattle

Staggering, dyspnea, collapse Often so rapidly fatal that illness is not observed- found dead

What is likely cause of death based on this presentation

B. Anthracis

What does B. Anthracis cause in horses

Fever, chills, severe colic, anorexia, depression, weakness, bloody diarrhea, swelling of neck, sternum, lower abdomen and external genital Death in 2-3 days post symptoms

What species is somewhat resistant to anthrax

Pigs

If pigs do show signs of B. Anthracis what are they

Sudden death, oropharyngitis, mild or chronic form

What is oropharyngeal anthrax characterized by in pigs

Rapidly progressive swelling of throat- cause of death may be suffocation

Why don’t you open carcass with suspected anthrax

Oxygen promotes endospore formation

What are some on site presentations of anthrax in dead animal

Widespread hemorrhage, absence of rigor mortis, bloated, bleeding at mouth, nose, anus and vulva

When sampling sources to dx B. Anthracis you must wear

PPE

How can you dx B. Anthracis

1. Y phage lysis- y phage is specific to B. Anthracis and some B. Cereus isolates 2. Capsule staining- M’Fadyean stain aka Polychrome Methylene blue 3. Susceptibility to penicillin

What stain do you use to stain capsule to dx B. Anthracis

M’Fadyean stain aka polychrome methylene blue

A phage was used to dx suspected B. Anthracis, what phage was that and what does this image show

y-phage, image shows y-phage lysis

What stain is this and what is it identifying

M’Fadyean stain aka polychrome methylene blue to identify capsules of B. Anthracis

What test strips can you use to dx B. Anthracis

1. BaDX 2. Tetracore Redline Alert

B. Cereus has shown to be ___so can share DNA with B. Anthracis

Naturally competent

What are the plasmids in the African strain of B. Cereus

1. PBCXO1 2. PBXCO2

What does PBXCO1 do in African strains of B. Cereus

Toxin genes and functional hasABC genes that encode hyaluronic acid capsule

What does PBXCO2 African strains of B. Cereus do

Plasmid has capBCDAE genes- encode poly-y-D-glutamic acid capsule

What are the two plasmids in American strains of B. Cereus

1. PBCXO1 2. PBC210

What does PBCXO1 do in the American strain of B. Cereus

Functional hasABC genes- encode hyaluronic acid capsule

What does the PBC210 toxin in American strain of B. Cereus do

Carry bpsX-H operant that encodes for a capsule

How do you control anthrax in animals

Vaccine- live culture strain with no PXO2 (no capsule, a virulent)

How do you destroy carcasses infected with anthrax

Incinerate carcass and burn soil

If you bury a carcass with anthrax, it must be buried >__ft with ___away from water sources

6.5ft with quick lime (caustic calcium oxide)

What treatment is available for animals with anthrax

Penicillin G or oxytetracycline

If inhalation anthrax is possible what is the treatment and why

Doxycycline and ciprofloxacin for 60 days because spores are latent and require long course of antibiotics

How is cutaneous anthrax treated

With penicillin

What is used to tx humans infected with anthrax

Obiltoxaximab and Raxibacumab are monoclonal antibodies to PA

Are Clostridial spp gram positive and negative and what shape

Gram positive rods

Most Clostridial species are strict ___organism

Anaerobic

Are Clostridial species spore forming or no

Spore forming, bulging in mother cell

What is the causative agent of tetanus

Clostridium Tetani

What hemolysis is shown with C. Tetani

B-hemolysis and swarming growth on blood agar

What species are highly susceptible to C. Tetani

Horses and humans

What species are moderately susceptible to C. Tetani

Ruminants and pigs

What species are somewhat resistant to C. Tetani

Carnivores

Infection with C. Tetani is caused by ___

Contamination of tissue wounds

What is the pathogenesis of C. Tetani

1. Spores enter wound and anaerobic conditions lead to germination 2. Anaerobiosis caused by deep penetrating wound, necrotic tissue 3. Facultative anaerobes take up O2 creating environment for obligate anaerobe 4. Tetanolysin- hemolytic pore forming toxin that lyses RBC’s Tetanospasmin- tetanus neurotoxin that binds presynaptic terminals of LMN, travels retrograde up axons, enters inhibitory interneurons in brain and spinal cord, blocks release of GABA and glycine inhibitory NT—> spastic paralysis

What is ascending rigid paralysis from C. Tetani

Animal not highly susceptible, localized tetanus/ spastic paralysis at toxigenic site

What is descending rigid paralysis with C. Tetani

Highly susceptible species with vascular dissemination, generalized tetanus

What are some key signs of rigid paralysis from C. Tetani

1. Lockjaw- trismus 2. Raised eyebrows and grinning- rises sardonicus 3. Sawhorse stance 4. Death- respiratory arrest in 1-2weeks

Based on these photos, what are you concerned about

C. Tetani

How can you dx C. Tetani

1. Clinical signs 2. Gram stain 3. Culture 4. PCR for tetanus toxin genes from wounds

In dogs what disease do you need to differentiate tetanus from

Strychnine poisoning

What is the tx for tetanus

1. Antibiotics- penicillin (DOC), tetracycline, metronidazole, clindamycin 2. Anti-TeTN antibodies 3. Surgical debridement of wounds

How often do horses get tetanus antitoxin

Every 12hrs along with muscle relaxants and barbiturates/ sedatives

Dogs and cats can be given horse raised tetanus antitoxin but it can cause ___

Anaphylaxis

How long does recovery from C. Tetani take and why

Months, because toxin binds irreversibly so requires regeneration of synapses

How do you control C. Tetani

Vaccinate

How often should farm animals be vaccinated for C. Tetani

Yearly and after dangerous wound

Mares should be vaccinated for C. Tetani during last ___weeks of pregnancy

When do foals get vaccinated for C. Tetani

5-8 weeks old

Should animals who survive tetanus be vaccinated

Yes, regularly because endospores can persist and germinate later