ID Exam 1 Matching

MORPHOLOGY
Gram-positive bacillus (rod)
- "Square-cut" ends
- Occurs singly, in pairs, or in long chains ("string of pearls")
Spore-forming
- Oval spores
- Centrally located
Encapsulated
Nonmotile

B. anthracis (Anthrax)Growth Media
Grows best on blood agar at 37 degrees Celcius
- Nonhemolytic
- Produces rough colonies, with irregular edges ("Medusa head")
Liquefies gelatin
- "Stabs" resemble "inverted fir trees"

Antigenic Structure
Has 3 exotoxins: protective antigen, edema toxin, lethal toxin

For disease to occur, the following must be present: edema toxin, lethal toxin, and capsule

Diagnostic Tests for this organism include:
-DFA test (direct fluorescent antibody)
-Nucleic acid amplification tests (PCR)
-Europium nanoparticle-based immunoassay (ENIA)

TREATMENT
Drugs of first choice
- Ciprofloxacin
- Doxycycline

MORPHOLOGY
Gram-positive bacillus that commonly appears to be Gram-Negative

Terminal Spores
-"tennis racket" or "drumstick" appearance

Growth Media
-Blood agar at 37C under anaerobic conditions
-Liquid medium with reducing agents under aerobic conditions
-Growth on solid media
-- colonies with compact center and irregular edges, with a loose meshwork of filaments spread on the surface ("sprig of maidenhair fern")
-Difficult to grow and identify

Antigenic Structure
produces 2 exotoxins: tetanolysin and tetanospasmin

Diagnostic Tests for this organism include:
Mouse virulence assay
-recover organism from culture
-tetanus antitoxin neutralization test
-confirms production of tetanospasmin

TREATMENT
Drug of first choice - Metronidazole
*Penicillin is contraindicated

ANTIGENIC STRUCTURE
-Produces an exotoxin with 7 antigenic variants
-Only one toxin is produced by most individual isolates
-The toxins are neurotoxins
*type A exotoxin is the MOST POTENT POISON known to man

Diagnosis (very difficult)
Confirmation via demonstration of the presence of the toxin in feces or serum

Food or biospecimen may be analyzed for neurotoxin in the mouse virulence assay

TREATMENT
-Elimination of the source of toxin
-Elimination of any unabsorbed toxin
-Neutralization of any unbound toxin with specific antitoxin
-Provide supportive care (Mechanical Ventilation)
**Trivalent botulinum antitoxin is available

MORPHOLOGY
Slender, Gram-Positive rods
- Anaerobic
- Large, oval, subterminal spores
Nonhemolytic
Multiple and varied fermentation products
-particularly short chain fatty acids
Numerous degradative enzymes - Hyaluronidases, Collagenases, Proteases

Growth
-CDC Agar
-Cycloserine-cefoxitin-fructose agar (CCF agar)

Antigenic Structure
Two toxins: Enterotoxin (toxin A) and Cytotoxin B (toxin B)
Other virulence factors - bacterial surface layer proteins (SLP) ----> produces disease

Diagnosis
-History and symptomatology
-Colonoscopy
-ELISA
-Isolation and identification of the organism from a stool specimen, as well as toxin detection, requires initial cultivation of a selective agar medium

Treatment (Oral Antiobiotic Therapy)
-Metronidazole
-Vancomycin

Antigenic Structure
A variety of toxins and enzymes are produced (at least 12)
-Alpha toxin (lecithinase)
-Beta toxin
-Iota toxin
-Kappa toxin
-Mu toxin
-Nu toxin

Diagnostic Tests
-Nagler Reaction- detects the presence of Alpha toxin

Treatment
Drug of first choice - high dose penicillin + Clindamycin
Mechanical Ventilation (hyperbaric oxygen chambers)

Morphology
-Gram-positive bacillus
-metachromatic granules

Growth Media
-Organisms grow well on Loeffler's coagulated serum slant
-Frequently characterized via growth on a cysteine-tellurite agar plate

Antigenic Structure
-K antigen
-Diphtheria Exotoxin

Diagnostic Tools
Elek immunodiffusion test +
PCR

Treatment
-Early Administration of antitoxin
-Drug of first choice - Erythromycin

Morphology
-very small gram-negative coccobacillus
-encapsulated
-possess fimbriae

Growth Media
--traditional media -> Bordet-Gengou Medium

Antigenic Structure
-Fimbriae
-pertactin
-histamine-sensitizing
protein exotoxin

Diagnostic Tests
Nasopharyngeal swabs using
-Direct fluorescence antibody stains (DFA)

Treatment
Oxygen inhalation;
sedation; steroid therapy
Drug of 1st Choice
-Erythromycin/Clarithromycin/Zithromycin

Morphology
Small, Gram-negative coccobacillus
Wayson bipolar stain

Growth Media
Growth is optimal on blood agar at 28C

Antigenic Structure
V-W antigens (YOPs)
Lipopolysaccharide (LPS)

Diagnostic Tool
Bipolar Wayson stain + Bubo
aspirate DFA stain

Treatment
Drug of 1st choice - Streptomycin +/- Tetracycline

Morphology
Spiral-shaped or curved Gram-negative bacillus
Motile
Nonencapsulated
Nonsporeforming
Microaerobic

Growth Media
Fresh chocolate (hemolyzed blood) agar
Modified Thayer-Martin agar

Antigenic Structure
produce a urease enzyme

Diagnostic Tests
Urea breath-test
Tissue biopsy
Immunoserology
Antigen detection

Treatment
Combination antibiotic therapy is standard
-Amoxicillin
-Clarithromycin
-Tetracycline
-Metronidazole
-Bismuth Subsalicylate