gram pos rods Flashcards
What 2 gram pos rods form spores?
bacillus and clostridium
Bacillus: gram- or +? spore forming? shape? prefers aerobic or anaerobic? motility?
Gram pos rods
spore-forming
preferes aerobic
motile (except for B anthracis)
Bacillus anthracis: threat?
where do you find it?
How can you get it?
Category A biothreat
found in contaminated soil or animal products (cattle farm, sheep or goat hair)
cutaneous, ingestion, inhalation
Cutaneous B anthracis?
dark coal-like lesions, painless papule
ulcer surrounded by vesicles (necrotic eschar)
20% mortality
GI (ingested) B anthracis?
Upper GI- ulcers in mouth and throat
Lower GI- affects terminal ileum and causes bloody diarrhea
100% mortality
Inhalation B anthracis?
2+mo latent period
Starts nondescript-fever, cough, headache, chills, vomiting
2nd stage- worsening fever, mediastinal lymph nodes swell (observed growth in mediastinum in chest x-ray), edema, meningeal effects in 50%
shock and death within 3 days if untreated
Anthrax diagnosis: what is the shape?
what are the 3 tests needed and results?
Treatment?
box-car shaped gram+ rods
Test for motility (non-motile), hemolysis (non-hemolytic), and penicillin susceptibility (penicillin susceptible)
treat with penicillin or ciprofloxacin if pen-resistant
What are the 2 gram pos rods that cause food poisoning?
***Bacillus cereus and
Listeria monoctyogenes: Type of bacteria?
where is it found?
gram+ non-spore forming rod
Found in animals (fecal flora), environment (soil, sewage, stream water), and refrigerated foods (mainly food-borne illness because can grow at fridge temps)
Listeria monoctyogenes pathogenesis?
Bacteria invade epithelial cells, M cells, macrophages by internalin protein. Can then release phospholipases.
Via ActA gene it uses host actin to move bacteria into adjacent cells (avoiding the immune system because they don’t leave the cells)
Who is particularly at risk for L monocytogenes?
What patient populations are at risk?
Patients w/defects in cellular immunity
Neonates (can cause meningitis in neonates)
Elderly (Flu-like)
Pregnant women (bacteremia)
Listeria diagnosis: Hemolytic?
catalase pos or neg?
What temp does it prefer and why?
What else does it look like?
B-Hemolytic (need to scrape it aside to see hemolysis)
catalase pos
prefers room temp because it’s motile (umbrella motility-grows/moves more at top where oxygen is greater), at 37C it is non-motile
Looks like strep but it’s catalase pos
L monocytogenes treatment?
penicillin/ampicillin (preferred)
Erysipelothrix rhusiopathiae: Type of bacteria? Growth environment? hemolysis? catalse pos or neg? motile? fermentor? What does it uniquely make?
pleomorphic gram pos rods (form long hairlike filaments)
facultative anaerobes (growth is somewhat poor in aerobic)
a-hemolytic
catalase neg
non-motile
weak fermentor
makes H2S (black) (only gram pos rod to do so)
E rhusiopathiae epidemiology?
found in soil and groundwater
mostly only disease in animals, but also is occupational hazard for butchers, farmers, etc
E rhusiopathiae disease?
treatment?
Erysipeloid: localized skin infection on fingers and hands
Septicemic form: rare, frequently associated w?endocarditis if it forms
Treat with penicillin
Corynebacterium diphtheriae characteristics? Type of bacteria? shape? color? Growth environment? hemolysis?
Pleomorphic gram pos rods that form small non-hemolytic white colonies
look like the letters V, X, and Y, or chinese lettering
facultative anaerobe (grows aerobic)
Corynebacterium diphtheriae: how is it spread?
what does it cause?
How do you treat it?
spread via resp droplets or direct contact with cutaneous infection
causes diphtheria: pharyngitis with patchy exudate on tonsils, uvula, and soft palate.
Toxin can injure that heart or cause paralysis if it reaches the heart or CNS
Treat with antitoxin and penicillin/erythromycin
Arcanobacterium hemolyticum characteristics: bacteria type and shape? catalase pos or neg? hemolysis? spore forming?
non-spore forming gram pos rod that forms club shaped/V formation.
catalase neg
B-hemolysis (like group A strep)
Arcanobacterium hemolyticum: who gets it?
What does it cause?
young adults (15-25yo)
pharyngitis, fever, rash (sometimes)
Actinomycetes: Nocardia characteristics: bacteria type? aerobic or anaerobic? catalase pos or neg? How long does it need to incubate? What is best stain type?
strict aerobic gram pos rods, look like beaded rods
catalase pos
prolonged incubation (7+ days required)
best to do acid fast
Nocardia and rhodococcus disease? Treatment?
pulmonary diseases, normally treated with sulfonamides
Nocardia epidemiology? who mainly gets it?
worldwide in soil
inhaled or cutaneous acquisition
(mainly in immunocompromised patients)
Tropheryma disease?
Whipple’s disease
