STEP 1 Gram Positive Bacteria 2 Flashcards
Causative agent of anthrax?
Algorithm findings?
Which toxin is produced?
**Only bacterium with a ____ capsule…contains ____?
Bacillus anthracis
Gram + aerboic, spore-forming rod
Produces the anthrax toxin
only bacterium with a POLYPEPTIDE CAPSULE (contains D-glutamate)
What are the two types of anthrax? Which is deadlier? Which one is commonly called Woolsorter’s disease?
Cutaneous (less deadly) and pulmonary anthrax (definitely deadly).
Woolsorter’s disease is caused by inhalation of spores from contaminated wool
Features of cutaneous anthrax
Uncommonly progresses to what?
Ulcers with BLACK ESCHAR which is painless and necrotic. Uncommonly progresses to bacteremia and death
Pathogenesis of pulmonary anthrax
INHALATION of spores –> ILI that rapidly progresses to fever, pulmonary hemorrhage, mediastinitis, and shock
Bacillus cereus pathogenesis
Causes FOOD POISONING. Spores survive cooking rice or pasta. Keeping the food warm results in SPORE GERMINATION and ENTEROTOXIN FORMATION
Emetic type of B. cereus
N/V causes by preformed toxin. Commonly associated with “reheated rice”
N/V within 1-5 hours
Diarrheal type of B. cereus
Causes watery, NON-BLOODY diarrhea and GI pain within 8-18hrs
Listeria monocytogenes algorithm findings
Gram + rod
Facultative intracellular microbe
How is listeria acquired?
- Ingestion of UNPASTEURIZED DAIRY PRODUCTS and DELI MEATS
- Transplancental transmission
- Vaginal transmission during birth
How does listeria avoid antibody?
Moves through cell cytoplasm via actin polymerization and imbeds in cell membrane
**Characteristic TUMBLING MOTILITY
Listeria and LPS
**ONLY GRAM + ORGANISM TO PRODUCE LPS
Listeria causes what in pregnant women (3), infants and neonates, immunocompromised patients, and healthy individuals
Preggers: amnionitis, septicemia, spontaneous abortion
Infants and neonates: granulomatosis infantiseptica and neonatal meningitis
Immunocompromised: meningitis
Healthy: mild gastroenteritis
How to treat listeria..if gastroenteritis? meningitis?
Gastroenteritis is usually self-limited
Ampicillin in infants, immunocompromised, and elderly
Actinomyces and Nocardia appearance
Both form long, branching filaments RESEMBLING fungi
Actinomyces algorithm: gram stain aerobic or not acid fast stain flora location pathogenesis treatment
Gram + anaerobe NOT acid fast Normal oral flora Causes oral/facial abscesses that drain through the sinus tracts. Forms YELLOW "SULFUR GRANULES" Treat the sombitch with PCN
Nocardia algorithm: gram stain aerobic or not acid fast stain flora location pathogenesis treatment
Gram + AEROBE WEAK acid fast Found in SOIL Causes PULMONARY infections in IMMUNOCOMPROMISED and CUTANEOUS infections after TRAUMA in IMMUNOCOMPETENT Treat that sombitch with SULFONAMIDES
3 mycobacteria microbes
Stain?
Mycobacterium tuberculosis
M. kansasii
M. avium-intracellulare
*All mnycobacteria are acid-fast organisms
M. Tb causes what?
Symptoms?
Causes TB…often resistant to multiple drugs…hence the multi-drug regimen
Symptoms: fever, night sweats, weight loss, and hemoptysis
M. kansasii causes what?
TB-like symptoms
MAC is present in which patient population?
Prophylactic treatment?
MAC typically present in AIDS patients once T-cell count drops below 50.
Treat prophylactically with azithromycin
TB:
_____ factor in virulent strains inhibits _____ maturation and induces release of ____
Cord factor in virulent strains inhibits macrophage maturation and induces release of TNF-alpha
TB:
______ (surface glycoplipids) inhibit _____ fusion
Sulfatides (surface glycoplipids) inhibit phagolysosomal fusion
Mycobacterium algorithm:
Acid fast bacilli…does NOT gram stain well
Two types of leprosy…which is lethal?
Lepromatous and Tuberculoid forms.
Lepromatous form is lethal
TB animal reservoir in US?
Armadillos
Lepromatous form presentation:
Diffusely over skin
Leonine facies
Communicable
Low cell-mediated immunity with a humoral Th2 response
Tuberculoid form presentation:
Limited to a few, hypoesthetic hairless skin plaques
High cell-mediated immunity with a largely Th1-type immune response
