Anaerobic Bacteria Flashcards
Where do anaerobic bacteria live
GI tract of mammals
Are gram positive or gram negative anaerobes spore forming?
Gram positive -> clostridium spp
What are the anaerobic, gram negative, non-spore forming bacteria?
Fusobacterium necrophorum
Dichelobacter nodosus
Porphyromonas spp
Prevotella spp
How should you submit your sample if you suspect anaerobic bacteria for culture?
In anaerobic conditions .. shame on your cow if you got this wrong
What signs are consistent with anaerobic infection?
Foul smelling discharge Gas in tissue/discharge Necrotic tissue and abscess Pyogranulomatous lesions with sulfur granules Infections near/on mucous membranes Do not respond to aminoglycosides
What type of bacteria are clostridium sp?
Gram positive spore forming anaerobic rods
Where are clostridium sp found
Environment (soil)
Large bowel
_____________ toxin from clostridium perfringens is the most lethal toxin and considered a bioterrorism agent
Epsilon
What is the virulence and pathogenesis of clostridium?
All clostridium produce one or more protein toxin/ extracellular enzymes
Growth requires anaerobic conditions-> necrosis is common predisposing factor
What clostridium sp are neurotoxic
C. Botulinum
C. Tetani
C. Perfrignens
What clostridium sp are histotoxic
C. Chauvoei
C. Septicum
C. Novyi
C. Perfringens
What clostridium sp is enterotoxic
C. Perfringens
C. Difficile
What is the only clostridium sp that is neurotoxic, histotoxic, and enterotoxic?
C. Perfringens
___________ causes tetanus in humans and animals
Clostridium tetani
Where is C. Tetani found in the environment and where will it grow in the body
Soil and feces
Contaminated wounds
Clostridium tetani produces _______________ that will cause spastic paralysis
Tetanospasmin (potent neurotoxin)
Who are the hosts of C. Tetani
All animals
Horse > human > all other animals
What is the pathophysiology of tetanus?
Wound infection -> toxin produced in the wounds -> enters nerves by receptor mediated endocytosis -> retrograde transport along axons of peripheral motor nerves -> spinal cord -> prevents release of NT glycine and GABA
What is ascending tetanus? And who gets it?
Toxin travels from regional motor nerve of limb
occurs in susceptible animals (dog and cat)
What is descending tetanus? And who gets this most often?
Toxin in the blood steam affecting motor nerve centers in the head and neck first and then spread to the limbs
Humans and horses (more susceptible species)
Diagnosis of C. Tetani
History of wounds and clinical signs
Culture is often unrewarding -> Demonstration of toxin in serum or tissue is difficult
Serology
How do you treat C. Tetani infection
Antitoxin
Surgical debridement of wounds, hyperbaric oxygen
Supportive care
How is tetanus controlled?
Toxoid immunization (human, horse, small ruminant)
Post exposure prophylaxis
Prompt wound management
Aseptic surgical techniques
What determines species affinity of clostridium botulinum ?
Toxin type (A-G)
What causes botulism?
Food intoxication (food poisoning) due to consumption of food contaminated with botulinum neurotoxin
What is the pathogenesis of C. Botulinum?
Toxin absorbed from the GI tract and distributed in bloodstream
Occasional toxico-infectous forms
-> inhibits neurotransmitter release (ACh) -> flaccid paralysis
Symmetrical flaccid paralysis of muscles - hind limb paralysis and recumbence
Botulism
Skeletal muscle paralysis can lead to respiratory failure
Type E botulism is where?
Great Lakes- Erie and Huron
-> dead and dying fish eating birds, and dead fish
How do you diagnose botulism?
Demonstration of toxin in serum of animal
Toxin in food/stomach contents
MALDI TOF
ELISA
How do you treat botulism
Antitoxin (affects unbound toxin only)
Therapeutic drugs to enhance cholinergic neurotransmitter (ACh) release
Supportive care
How do you control botulism?
Toxoid immunization in high risk animals
Avoid feeding suspect foodstuff
What are the histotoxic clostridia?
C. Chauvoei
C. Septicum
C. Novyi
C. Hemolyticum
C. Sordellii
C. Perfringens
Produced toxins -> invasive infections -> fatal gas gangrene
Pathogenesis of Clostridum chauvoei
Endospore ingested -> lymphatic and blood -> Muscle -> trauma and tissue necrosis create anaerobic conditions -> germination and toxin production
Fermentation of muscle glycogen results in gas accumulation (hydrogen/methane) -> necrotizing myosis
What disease is caused by clostridium chauvoei?
Black leg
What lesions are seen in black leg?
Necrotizing myositis
Emphysematous swelling
Edematous and crepitant swelling of hip, shoulder, chest, back, and neck
Myocardium and diaphragm also can be affected
Clostridium novyi Type A causes what disease?
Exogenous gas gangrene
Big head in rams
Clostridium novyi Type B cause what disease?
Endogenous
Infectious necrotic hepatitis
Predisposed by fluke damage
C. Hemolyticum causes what disease?
Endogenous infection causing liver damage and bacillary hemoglobinuria in sheep and cattle
Malignant edema is also called?
Gas gangrene
What causes gas gangrene?
Wound infection by histotoxic clostridium
Serous, deep (anaerobic), traumatic wound -> gas formation and toxemia
How do you prevent malignant edema?
Surgical treatment of serious wounds to remove necrotic muscle, tissue, and contaminating materials
What are risk factors for development of malignant edema?
IM injection
Shearing, docking, lambing
Traumatic parturition and castration in cattle
C. Septicum causes what in sheep?
Braxy
Abomasum edema from endogenous spores
How do you diagnose histotoxic clostridium ?
FA
Direct gram stain form muscle
Anaerobic culture usually not rewarding
How do you treat and control necrotic myosistis?
Antimicrobials (penicillin_ -> only effective if given early in infection
Routine vaccination of farm animals with bacterin/toxicoids
What are the enteropathogenic clostridia?
C perfringens
C. difficile
C spirforme
C colinum
How is C perfringens classified
Based on four major toxins (alpha, beta, lots, epsilon) -> biotypes based on this
T/F: all C. Perfringens have alpha toxin
T
C. Perfringens type C causes ________________ in piglets
Necrotizing enteritis
C. Perfringens type D causes __________________ in sheep and goat
Enterotoxemia
- > overeating disease
- > pulpy kidney disease
What disease seen in sheep and goats presents as a fluid-distended intestine with petechial hemorrhage on the serosal surface.
C perfringens type D
Overeating disease
Pulpy kidney disease is caused by ______________________ and is characterized by ________
C perfringens type D
Rapid post mortem autolysis of the kidney
Pig enterotoxemia is caused by ___________ and infects pigs of what age?
Clostridium perfringens type C
Piglets in the first few days of life
C perfringens causes _________ in multiple species of animals
Necrotizing hemorrhagic enteritis
How do you diagnose an enteropathogenic clostridium?
Gram stain
Anaerobic culture
Toxin detect in stomach contents - serological test
How do you treat and control C perfringen infection
Hyperimmune serum
Antimicrobial therapy not generally effective for GI disease
Immunization - toxoid/bacterins
Avoid sudden diet changes that alter flora or damage mucosa
What disease is caused by clostridium difficile
Enterocolitis
Where is clostridium difficile found and who does it infect?
Colon and cecum
Human Horse Pig Cat Dog Rodent Other
What is dysbiosis?
Aka dysbacteriosis
Microbial imbalance in the body
How does disease result from C.dfficile?
Disruption of normal flora (disease or antimicrobial treatment) -> C.difficle proliferates (survives in spores)-> toxin production
What are the toxins produced by C.difficile?
ToxA - enterotoxin
ToxB- cytotoxin, synergistic with toxA
Most produce both toxins- some only produce toxB
Diagnosis of C.difficle?
Culture- obligate anaerobes
Selective treatment for spore germination
Direct toxin detection - tissue assay with Ab neutralizaiotn
Toxin antigen detection (ELISA, latex agent- toxA or ToxA/B)
How do you treat C.difficile?
Supportive therapy -diarrhea
Stop antibiotic if possible
Clindamycin should not be used in horse
Probiotics
Avoid anti-diarrheal
Fecal transplant
Clostridium spirofome is a commensal bacteria in what species? Disease arises from what?
Rabbits
Treatment with licosamides, macrolides, penicillins -> dysbiosis
Entertoxemia
Rabbit with a history of fluid-distended intestine and explosive diarrhea. On necropsy you see hemorrhage of the serosal surface
C. Spiroforme
What causes tyzzers disease. Who is affected by this disease ?
Clostridum piliforme
Laboratory animals
What is tyzzers disease?
Acute, fatal, diarrheal disease associated with focal liver necrosis
What are the gram negative nonspore forming anaerobes
Commensal of mucous membrane
Fusobacterium necrophorum Dichelobacter nodosus Bacteroides Porphyromonas spp Prevotella spp
Non-spore forming bacteria are found in _____________ infections involving breaks of mucosal or epithelium
Mixed bacterial
Often chronic infection with extensive purulence or necrosis
Fusobacterium necrophorum causes what lesions?
Foot rot -extensive necrosis and keratinocytes
Liver abscess
Calf diphtheria- necrotic laryngitis
Fusobacterium necrophorum is synergistic with what bacteria ?
Trueperella pyogenes and dichelobacter noduosus
Fusobacterium if found in what hosts
Ruminants
How do you diagnose fusobacterium necrophorum
Anaerobic culture
PCR
How do you treat foot rot?
Remove necrotic tissue
Dip in antiseptic foot bath
Antimicrobials
(Aminoglycosides and sulfonamides are not effective )
How do you control foot rot?
Keep feet dry and avoid mechanical injury
Vaccine in sheep and cattle
Foot rot in cattle is caused by _____________ but in sheep is caused by _________________
Fusobacterium necrophorum
Dichelobacter nodosus
