Gram + Anaerobic Spore Former

BSC 361

03/06/13

Clostridium

Gram + anaerobic spore former

C. perfringens-causes myonecrosis or gas gangrene as well as cellulitis

Introduced from enviroment or surgery

Toxins galore-many used for attachment of intestinal epithelium and changes in vasopermeablility.

Alpha=phospholipase C-causes tissue damage

Beta-necrotizing toxin involved in enteritis

C. tetani

Two toxins-tetanolysin and tetanospasmin (plasmid encoded)

Tetanospasmin is AB toxin binds to neuron and A portion is internalized

Blocks the release of neurotransmitters that inhibit activity

Lock-jaw, Bell tetanus risus sardonicus

C. botulinum-botulism

Toxin is similar to tetanus but binds to peripheral activational neurons. Can cause respiratory problems.

Most toxic toxin known.

Generally contracted from home canning (green beans)

Infant botulism-lack of competition

C. difficile-psuedomembranous colitis and antibiotic associated diarrhea

Bacteroides fragilis

Gram - anaerobe

Major component of intestinal flora

Has "non-toxic" lipid A

Irritable Bowel Syndrome caused by sensitivity to B. fragilis
lipid A.

Francisella tularensis-tularemia

Gram - intracellular pathogen-prevents phagosome-lysosome fusion. Can spread to liver and spleen.

Typically transmitted by insect bite (associated with animals)-many manifestations:

Skin, GI tract, eye, glands involvement with many organs

Brucella

Melitensis (goat) and suis (pig) and abortus (cow)

Brucellosis-slow developing serious infection

Able to survive phagocytosis-prevent PMN degranulation lives intracellular in spleen, liver and bones.

Get from unpasteurized milk, improperly cooked meat etc.

Rickettsia

Causes Rocky Mountain Spotted Fever-and typhus

Reproduce in endothelial cells-spots are a result of areas of cell death

RMSF result of tick bite-symptoms start 10-14 days post inoculation

Caused by R. rickettsii

Typhus

Epidemic-louse borne -R. prowazekii

Endemic-flea borne- R. typhi

Erlichia

Infects leukocytes

Sennetsu fever- caused by E.sennetsu-transmitted by tick

Coxiella burnettii

Causes Q fever

Picked up by inhalation of bacteria from environment

Acute or chronic disease-acute normal symptoms

Chronic-endocarditis or hepatitis

Coxiella lives in phagolysosome, Erlichia prevents fusion and reproduces in morula

Chlamydia

Elementary body-like spore

Reticulate body-vegetative cell

C. trachomatis

Trachoma- keratoconjunctivitis-leading cause of blindness

Passed casually

Oculogenital disease-conjuctivitis associated with genital infections in sexually active adults

Lymphogranuloma venereum-small painless lesion quickly goes away, then spread of organism through lymphatic system

Urogenital infections-largely assymptomatic in females leading to PID, etc.

Males have urethritis

C. pneumoniae

Passed by respiratory secretions

Plays a role in atherosclerosis

C. psittaci

Parrot fever

Infection through inhalation of dried bird feces

Mild symptoms-largely unreported

Eventually get pulmonary and nervous involvement