Gram (+) Rods Flashcards
Spore forming aerobe, zoonosis with no vector, associated with cattle that can lead to a cutaneous disease with edematous eschar
Bacillus anthracis
Edema factor and lethal factor released from anthrax toxin cause the eschar
Patient presents with pneumonia. Upon chest xray, there is mediastinal widening. Patient was recently at major sporting event. If not treated within 48 hrs, this disease is almost invariably fatal.
Bacillus anthracis - mediastinal widening due to hemorrhagic lymphadenitis
Inhalational spores have potential for biowarfare agent
Spore forming aerobe, associated with Chinese restaurants, rapid onset vomiting and diarrhea due to preformed emetic toxin
Bacillus cereus
Anaerobic, spore former, produces toxin that blocks release of glycine and GABA in spinal synapses, leaving excitatory neurons unopposed
Clostridium tetani
Associated with dirty puncture wounds and progresses from lockjaw to diffuse rigid paralysis
Clostridium tetani
What is the treatment of tetanus?
TIG (hyperimmune human globulin) to neutralize toxin + antibiotics (metronidazole or penicillin)
Floppy baby syndrome
Clostridium botulinum
buzzword: honey
Anaerobic, spore former, heat labile, produces toxin that blocks the release of ACh at the neuromuscular junction
Clostridium botulinum
Why shouldn’t you treat botulism with antibiotics?
In adults: there is no active infection! Just ingested preformed toxin
In infants: antibiotics will lyse the bacteria, releasing toxin and causing a potentially fatal toxemia
Thankfully, there is a trivalent antitoxin available
Anaerobic, spore former, non motile, produces an alpha toxin that is a lecithinase which causes massive hemolysis and tissue destruction
Clostridium perfringens
Toxin identified by Nagler reaction
Traumatic accident, contamination of wound with soil, tense tissue, fever
Clostridium perfringens - gas gangrene
What is the treatment of gangrene due to Clostridium perfringens?
- debridement
- delay closure of wound for as long as possible (since C. perfringens is anaerobic)
- clindamycin + penicillin
- hyperbaric chamber
Food poisoning, enterotoxin disrupts ion transport which causes a watery diarrhea that resolves within 24 hrs, associated with reheated meat dishes
Clostridium perfringens
Which is more common in the U.S., adult or infant botulism?
Infant
Anaerobic, spore former, normal flora of colon, toxins produced that are associated with antibiotic use and pseudomembranous colitis
Clostridium difficile
Which antibiotics put patients at most risk for developing Clostridium difficile infection?
broad spectrum - clindamycin, cephalosporins, amoxicillin, ampicillin
What is the treatment for Clostridium difficile?
metronidazole
Anaerobic, spore-former, stormy fermentation in milk media, shows double zone of hemolysis
Clostridium perfringens
Most common cause of meningitis is a renal transplant or cancer patient
Listeria monocytogenes
Aerobic, non spore former, beta hemolytic, facultative intracellular, tumbling motility, cold growth
Listeria monocytogenes
What is the manifestation of transplacental transmission of listeria monocytogenes? Neonatal acquisition?
Transplacental: granulomatous infantisepticum (disseminated granulomas with central necrosis) - tell mom to stay away from deli meat and soft cheese!
Neonatal: septicemia and meningitis
Aerobic, non spore former, club-shaped, toxin produced that inhibits protein synthesis by interfering with elongation, toxoid vaccine, most commonly infects throat (gray pseudomembrane), heart (myocarditis), and nerve (recurrent laryngeal nerve palsy)
Corynebacterium diphtheriae
Grows gray to black colonies in V or L or “Chinese letter formation” on tellurite medium. Can distinguish toxigenic from non toxigenic strains with Elek test.
Corynebacterium diphtheriae
Toxin producing strains of corynebacterium are present in an individual due to?
transduction of toxin via a beta-prophage, and toxin is then produced by lysogeny
