Chapter 1.6 Bacillus And Clostridium Flashcards
What are the general characteristics of bacillus and clostridium?
Gram positive, spore forming rods
How do bacillus and clostridium cause disease?
By releasing potent exotoxins
What is the difference in oxygen use between Bacillus and Clostridium?
Bacillus is aerobic and Clostridium is anaerobic
*In an air tight Closet
What are the 2 pathogenic species of bacillus?
Bacillus anthracis and bacillus cereus
What disease is caused by bacillus anthracis?
Anthrax
What disease is caused by bacillus cereus?
Gastroenteritis (food poisoning)
What is unique about the structure of bacillus anthracis?
It is the only bacterium with a capsule composed of a protein that prevents phagocytosis
What group does bacillus anthracis mainly affect?
Herbivores (owns and sheep)
How can bacillus anthracis reach humans?
During direct contact with infected animals or soil or when handing infected animal products
When is the spore of bacillus anthracis activated?
When it is introduced to the host
Why is bacillus anthracis an ideal candidate for biological terrorism and welfare?
Because of it’s small size, stability and 100% lethality of pulmonary anthrax
What clinical appearance occurs with a cutaneous anthrax infection of bacillus anthracis?
A painless round black lesion with a rim of edema caused by releases of a potent exotoxin that causes localized tissue necrosis
What is a malignant pustule?
Painless round black lesion with a rim of edema caused by bacillus anthracis that an cause death if untreated
What is pulmonary anthrax?
When spores are taken up by macrophages in the lungs and transported to mediastinal lymph nodes causing mediastinal hemorrhage
What results from mediastinal hemorrhage?
Mediastinal widening and pleural effusion
How is gastrointestinal anthrax caused by bacillus anthracis?
Following ingestion of spores where bacillus anthracis matures and replicated in intestine where it releases exotoxins resulting in neurotic lesion in intestine
What is most often ingested that is contaminated with spores of bacillus anthracis?
Contaminated meat
What is the patient presentation with gastrointestinal anthrax?
Vomiting, abdominal pain, and bloody diarrhea
Why does anthrax have such a high mortality rate?
From the release of exotoxin
How is bacillus cereus different from bacillus anthracis?
Bacillus cereus is motile, non-encapsulated, and resistant to penicillin
How does food poisoning occur from bacillus cereus?
Bacillus cereus deposits and germinates in the food and release enterotoxin
What are the 2 enterotoxins that cause food poisoning?
Heat-labile toxin and heat-stable toxin
What is the clinical presentation of food poisoning from heat-labile toxin from bacillus cereus?
Nausea, abdominal pain and diarrhea lasting 12-24 hours
What is the clinical presentation of food poisoning from heat-stable toxin from bacillus cereus?
Short incubation period followed by severe nausea and vomiting with limited diarrhea
What is the affect of antibiotic therapy for bacillus cereus food poisoning?
*Be serious, Dr Goofball– since the food poisoning is cause by the preformed enterotoxin, the antibiotic therapy will not alter the patient’s symptoms
What are the general characteristics of Clostridium?
Gram-positive, spore forming rods, and anaerobic
What diseases are associated with Clostridium?
Botulism, tetanus, gas gangrene, and psuedomembranous colitis
How does clostridium harm humans?
Secreting powerful exotoxins and enzymes
What are the mechanism of Clostridium botulinum?
Produces lethal neurotoxin that blocks release of Ah from presynaptic nerve terminals in ANS
What is the clinical presentation of clostridium botulinum?
Rapidly fatal food poisoning and flaccid muscle paralysis
How is adult botulism transmitted?
Eating smoked fish or home-canned vegetables
What is the clinical presentation after ingesting adult botulism?
Initially develop bilateral cranial nerve palsies causing double vision (Diplopia) and difficulty swallowing (dysphagia)
Leads to general muscle weakness and respiratory paralysis and death
How is infant botulism transmitted?
When infants ingest food contaminated with clostridium botulinum
Ex. Fresh honey
What is the clinical presentation of infant botulism?
Constipated for 2-3 days
Difficulty swallowing and muscle weakness
“Floppy” babies
What disease does clostridium tetanus cause?
Tetanus
What is tetanus?
Disease that follows a puncture wound by a rusty nail or skin trauma by any object contaminated with spores
Where are clostridium tetani spores found?
Soil and animal feces
How does clostridium tetani survive in humans?
Deposit in a wound any germinates as long as there is localized anaerobic environment (necrotic tissue)
What exotoxin is released from clostridium tetani?
Tetanospasmin
What is the clinical presentation of clostridium tetany?
Tetany- sustained contraction of skeletal muscle
Especially in muscles of the jaw
Risks sardonicus- grotesque grinning from facial muscle spasm
What is trismus?
Muscle spasms of the jaw muscle
Also called lockjaw
What disease is caused by clostridium perfringens
Gas gangrene
Where is clostridium perfringens found?
Soil where they mature in anaerobic environment and produce gas
What are the 2 classes of infection with clostridium perfringens?
Celllulitis/wound infection
Clostridial myonecrosis
What is the clinical presentation of a person with cellulitis/wound infection?
Necrotic skin that is moist, spongy, crackling of the skin from the pockets of gas (crepitus)
What is the clinical presentation of someone with clostridial myonecrosis?
Pockets of gas in muscles and subcutaneous tissue
Thin, blackish fluid from skin
What bacteria causes psuedomembranous enterocolitis?
Clostridium difficile
What are the affects of exotoxins released by clostridium difficile?
Toxin A causes diarrhea
Toxin B is cytotoxic to the colon
What is the clinical presentation of someone with clostridium difficile?
Severe diarrhea, abdominal cramping, and fever
What shows on the colonoscopy of a person with clostridium difficile?
Red inflamed mucosa
Areas of white exudate (psuedomembranes)
Necrosis of mucosal surface
