| Clostridium | Gram +ve rods
Produce endospores
Diarrhea, colitis and botulism
Ladle shaped |
| c. difficile | Diarrhea and colitis
Part of normal GI flora
Disease develops after 5-10 of antibiotics treatment (kills competitors of c.difficile)
Enterotoxin A and B
Smells like horse in lab culture
ELISA and 16s rRNA (Some strains are known to produce actin – specific
ADP-ribosyltransferase (binary toxin) such as
ribotypes 027) |
| Which enterotoxin of c.difficile is more toxic? | B
Causes actin to depolymerise resulting in disruption of cellular
cytoskeleton |
| Clostridium tentani | Gram +ve, motile, spore forming rods
Strict anaerobe!!
Looks like drumsticks
Disease: tetanus
Produces toxins that lead to spastic paralysis
Neither toxins nor antibodies to the toxin are detectable (toxin rapidly bound to motor neurons and internalized). |
| Clostridium botulinum | Large, fastidious, spore forming Gram +ve anaerobic rods
Divided into 4 groups depending on phenotypic and genotypic properties
7 antigenically distinct botulinum toxins (A-G) |
| C.botulinum | A-B toxin: A light chain, B heavy chain (Complex toxin with nontoxic protein that protects the neurotoxin in the digestive tract)
Leads to flaccid paralysis
Home canned foods
Easier to culture if specimens, food or stools are heated @80°C for 10 min
to kill non-sporing bacteria |
| What is an exception to the non-spore forming anaerobes? | Bacteroides fragilis |
| Non-spore forming Gram -ve rods | 5 important genera
– Bacteroides
– Fusobacterium
– Parabacteroides
– Porphyromonas
– Prevotella
Predominant bacteria on mucosal surfaces outnumbering Aerobes by 10-1000 fold |
| bacteroides | B.fragilis
Surrounded with a polysaccharide capsule w/o endotoxin activity
Growth stimulated by bile
Pleomorphic Gram –ve rods
Grow rapidly in anaerobic environment |
