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What does Columbia CNA stand for? What is it's use? Important ingredients?
- Columbia colistin-nalidixic acid
- Selective AND differential media
- For isolation/differentiation of gram +
- Sheep blood: for hemolysis
- Colistin and nalidixic acid: selects for gram pos
General bacillus - microscopic appearance? ___robic? Grows on ____? Disease?
- Large gram + bacilli in chains ("boxcars"
- aerobic and facultative anaerobic
- Grows on BAP, Choc, PEA, blood culture media, nutrient broths
- Frequent contaminants - diagnose carefully
- *NOTE - most are sensitive to penicillin
General bacillus - normal environment? Normally cause disease?
- Found in soil
- endospores: highly resistant, remain dormant until deposited in suitable environment for growth
- Normally disease wild/domestic animals
Bacillus infections acquired by which methods?
- Traumatic introduction
Bacillus cereus colonial morphology
- HIGHLY B-hemolytic
Bacillus cereus diseases with explanation
- Food poisoning: mainly rice
- toxins - hemolysin BL, nonhemolytic enterotoxin, cytotoxin K, cereulide
- symtpoms within 1-18 hours after ingestion
- *NHE = darrhea
- *cereulide = vomiting
- Wound/eye infections: contamination with soil or foreign body
- Total blindness after 48 hours (ocular injury)
- systemic infections for immunocompromised
What bacillus cereus toxins are associated with diarrhea and vomiting?
- diarrhea: nonhemolytic enterotixin
- vomiting: cereulide
Bacillus anthracis diseases with information
- Cutaneous: lesions form on skin
- most common
- eschar (necrotic central area) forms in ring of vesicles, heals 1-2 weeks leaving scar
- 1% fatality rate
- GI: lesions form in GI tract
- spores ingested with food
- lesions in ororpharynx or intestinal tract
- edema of throat/chest
- severe nausea/vomiting blood/diarrhea
- 25-60% mortality (usually toxemia/sepsis)
- Pulmonary: lesions form in lungs
- AKA Woolsorter's Disease
- flulike symptoms - abrupt and severe
- abnormal chest x-ray, edema, shock, death
- shock/death within 24-36hrs after symptoms
- 80%+ mortality
What are the three proteins in anthrax toxin w/ function?
- Protective antigen (PA): provides entry to your cells
- Edema Factor (EF): causes influx of liquid to cell
- Lethal Factor (LF): kills cells
How do you ID bacillus anthracis? What are the two most important factors?
- Gram: gram pos rods ("strings of pearls)
- endospore formation: clear, oval, within rod
- Culture: nonhemolytic (most other spp are beta)
- wispy, feathered edges, "medusa head"
- Direct detection: molecular or antigen-based methods
- Commercial Biochemical ID systems available
- MOST IMPORTANT: NO HEMOLYSIS, NON-MOTILE
Appearance/reason for use of bacillus anthracis on various culture media
- SBA: no hemolysis
- CNA: inhibits gram - (removes contamination)
- Phenylethyl alochol: inhibits gram - (removes contamination)
- Bicarbonate agar: induces capsule formation
- MYP, PEMBA, BCM: isolate B. cereus w/ combo of egg yolk, mannitol, and polymyxin B
- Chrome agars: colormetric
Therapies for anthrax infection?
- prophylaxis with ciprofloxacin or doxycylcine recommended after aerial exposure
- Vaccine available to at-risk individuals (5 doses, annual boosters needed, not pleasant)
What are Brevibacillus and Paenibacillus?
- Ubiquitous bacteria, usually contaminants
- Rare opportunistic infections (surgical wounds, meningitis after trauma, pneumonia)
- RARELY require ID (unless isolated from sterile site)