Anaerobes Flashcards
Treatment of anaerobic infections
Penicillin, Penicillin+betalactamase inhibitor, 2nd generation cephalosporins, carbapenems
Which are second generation cephalosporins?
Cefuroxime, cefoxitin, cefotetan.
What organism causes pseudomembranous colitis?
C. Difficile
Characteristics of C. diff.
Gram positive anaerobic spore-forming bacillus.
What is C. diff resistant to?
Many many antibiotics including beta lactams, clindamycin, cephalosporins, perhaps fluoroquinolones.
Diagnosis of C. diff?
EIA toxin assay, PCR.
Toxin A
Enterotoxin, causes neutrophil chemotaxis.
Toxin B
Cytotoxin, causes tight cell junctions to fail. Increases permeability of the intestinal wall to cause diarrhea.
Worst possible complication of C. diff?
Toxic megacolon and septic shock.
How to treat C. diff?
Metronidazole and oral vancomycin, fecal transplant therapy.
Clostridium perfringens gram stain?
Positive rod, but doesn’t hold it well at all.
C. perfringens plate?
Double zones of hemolysis
Where is C. perfringens from?
GI tract flora.
C perfringens alpha toxin
Mediates hemolysis, vascular permiability and tissue destruction
Diseases caused by C. perfringens
Gas Gangrene, cellulitis, emphasematous cholesystitis, food poisoning (spores and heat labile toxin).
How to treat C. perfringens?
Penicillin
C. tetani causes…?
Spastic paralysis because of decreased GABA.
How can C. tetani survive in soil?
Terminal spores.
C. Botulinum causes…
Flaccid paralysis due to AB toxin
How can somebody be infected with C. botulinum?
Improperly canned foods, spore contamination of honey
Most common gram negative anaerobe to cause disease?
Bacteroides fragilis
Characteristics of bacteroides fragilis?
Capsule, tolerant of oxygen due to catalase and SOD.
Which organism causes sulfur granules?
Actinomyces.
How does Actinomyces appear under the microscope?
Gram positive and branching. Anaerobic only.
Nocardia nova appearance under a microscope?
Stains w/ a modified acid fast stain. Gram positive beaded branching bacilli. Anaerobic and aerobic
How to treat novocardia nova?
With TMP-SMZ
Mycobacterium fortuitum
Grows much faster than MTB, can retain a gram stain and often grows in contaminated water supply. Treat w/ macrolides+beta lactams.
Corynebacterium diptheriae appearance
Gram positive bacillus that produces an exotoxin
How does diptheria cause death?
Causes thickening and toughening of pharyngeal membranes.
