I would like to add respective module name , with each organism, for those students which follow module system.

Gram Positve Rods

This include four genera, which are i. Bacillus ii. Clostridium, iii. Cornyebacterium etc
Bacillus:

Bacillus anthracis ( Respitratory module)

1. cause Pulmonary anthrax when its spores are inhaled ( woolsorter's disease)
2. cause cutaneous anthrax when spore enter through wound from soil
3. its capsule is composed of D-glutamate , making it antiphagocytic.

Labs:

1. In case of pulmonary anthrax, mediastinal widening seen on chest xray
2. hemorrhagic mediastinitis could be present
3. Gram +ve rods in chains seen on gram staining
4. direct antibody fluorescent antibody test or ELISA test

Bacillus cereus (GIT module)

1. food poisoning after eating reheated fried rice.
2. watery, nonbloody diarrhea

Mechanism of enterotoxin
it add adenosin diphosphate ribose to G protein which sitmulates adenylate cyclase and leads to increase conc. of cAMP inside enterocyte. This mechanism is same as that of Cholera toxin.
Labs:
Not specific
Clostridium
bacterias in this group are anaerobic, spore forming, gram +ve rods

Clostridium tetani ( neuro module)

1. cause tetanus i.e lockjaw
2. mode of transmission is by spore present in soil through skin wounds.
3. exotoxin is produce by bacteria at wound site, which than carried to CNS, by mean retrograde transport.
4. In CNS it act on ganglioside receptors and blocks realease of inhibitory transmitters at spinal synapses.

Labs:

1. No specific diagnostic but there may be clinical findings which are
2. lockjaw
3. exaggerated reflexes
4. Arching of back muscles ( opisthotonos),
5. Can be differentiate from botulinum toxin because in tetanis there is spastic paralysis of muscles while in case of botulism it is flaccid paralysis.

Clostridium botulinum ( neuro module)

1. Causes botulism by means of exotoxinin food.
2. Mostly by canned food.
3. botulinum toxin blocks release of acetylcholine.
4. preparation from exotoxin A used as Botox.

Clostridium perfringens ( GIT module)

1. causes food posioning by producing exotoxin. exotoxin causes diarrhea acting as a superantigen, just like S. aureus.
2. also cause gas gangrene.
3. Watery diarrhea with cramps

Clostrudium difficile (GIT module)

1. form pseudomembranes on colonic mucosa.
2. mostly commonly effect patients on prolong antibiotics therapy.
3. Causes non bloody diarrhea.

Labs:

1. Stool samples for presence of exotoxin and sigmoidoscopy reveal pseudomembranes on mucosa.

C. diphtheriae ( Respiratory module )

1. causes Diphtheria.
2. its toxin inhibits protein synthesis by ADP-ribosylation of elongation factor 2.

Labs:

1. Thick, gray pseudomembrane over the tonsils and throat.
2. L or V shaped gram +ve rods on Loffler's medium.
3. Staining by gram stain and methylene blue.