Gram Positive anaerobic Bacilli (spore formers) Flashcards
Describe a bit about Clostridium
○ normal flora in animals and humans
○ Can be strict anaerobes or aerotolerant
○ Found in soil, water and dust
○ Large gram-positive bacilli with swollen spores
○ Produce true exotoxins
What are some common species of Clostridium?
○ C. tetani
○ C. botulinum
○ C. perfringens
○ C. difficile
What does C. tetani cause? How?
○ Tetanus
○ The organism or its spores enter the body through a puncture wound, burn, gunshot or animal bite
○ uses necrotic cells to provide an anaerobic environment for germination of spores to active bacilli
What kind of toxin does C. tetani make? What does it do?
○ Tetanospasmin- causes convulsive contractions of voluntary muscles
○ Can cause “lockjaw” first and Respiratory paralysis can occur later on
How do you treat C. tetani?
○ combination of neutralizing antibodies to bing the free toxins and antibiotics to stop bacterial growth
○ Antibiotics include: penicillin, metronidazole or erythromycin
How do you prevent C. tetani?
○ DPT vaccine administered during childhood with boosters every 10 years
What does C. botulinum cause? How?
○ Botulism
○ a powerful neurotoxin
Botulism toxin
○ causes acute and flaccid paralysis in the muscles of the face, head, throat and then later the thorax, diaphragm, arms and legs
○ Respiratory paralysis = Death
How many Botulism toxins are there? What are the most common?
○ 7 (A-G)
○ B (50%), A(30%), E (12%)
Food-borne botulism caused by what?
○ Ingestion of preformed botulism toxin in improperly preserved food / food products
○ Can be found in canned food
How can food-borne botulism be treated?
○ Trivalent antitoxin against toxins A, B and E
○ However it must be done quickly before the antitoxin becomes useless
Wound botulism occurs due to?
○ organism germinated in a wound or abscess, though this is rare
○ improperly sterilized surgical dressing or contaminated castings
Infant botulism
○ Most common type of botulism
○ From spores that are consumed from soil, dust or honey
○ This is due to infants not having an established normal flora
What does C. perfringens cause? How? And what is so special about it?
○ Causes myonecrosis (gas gangrene)
○ Multiple toxins that cause cell lysis
○ Most common species of Clostridium isolated from clinical specimens
What do the toxins of C. perfringens do? What are they?
○ α-toxin, hemolysins, cardiotoxin, collagenase, fibrinolysin, enterotoxins and proteolytic enzymes
○ Can cause severe muscle destruction and production of gas pockets in tissues
○ Tissue becomes necrotic which promotes anaerobic conditions allowing the organism to proliferate
