Gram Positive Bacilli Flashcards
Spore-forming Anaerobic Gram+ bacilli indicates what species?
Clostridium spp.
Clostridium perfringens:
- Gram Stain
- Blood Agar
- Prelim ID requires what?
Gram+ Rods (short chains)
- Large, “Boxcar-shaped”
- Double-zone B-Hemolysis
- Lecithinase activity
Clostridium septicum:
- Gram Stain
- Blood agar
- Bacteremia association
Gram+ Rod (Large; forms chains)
- Swarming (not discrete colonies)
- Colonic adenocarcinoma/GI pathology
Clostridium botulinum:
- Diagnosis
- Common source?
- Toxin detection (serum, stool, vomit)
- Raw honey (infant botulism)
Clostridium tetani:
-Diagnosis
Clinical Diagnosis
-NO lab tests for toxin available
Clostridium dififcile:
- Culture medium/condition
- Colony morphology
- Gram stain
- Culture “odor”
- Cycloserine Cefoxitin Egg Yolk Fructose (CCFA)
- Strict Anaerobic conditions
- Yellow colonies w/ ground grass appearance; Fluoresce w/ UV light
- Gram+/variable, thin rods (subterminal/free spores)
- “horse manure” odor
Clostridium difficile:
-Molecular detection
Toxin A and Toxin B genes
Clostridium difficile:
-ELISA
Glutamate Dehydrogenase (GAD)* -More sensitive than stool Toxin
*Ag produced by C. diff
What C. difficile strain is associated with Severe C. diff colitis?
BI/NAP1/027 strain
PCR is able to detect C. difficile 027 strains; what mutations is found?
tcdC gene mutation
What are the NONspore-forming Anaerobic Gram+ bacilli species? (2)
- Actinomyces spp.
- Propionibacterium
Actinomyces spp.:
- Gram stain (*Identical to what other organism?)
- Colony morphology
Gram+ Rods - Branching/Filamentous
-White Cerebriform (Molar Tooth) colonies (A. israelii)
*Nocardia spp.
How do you differentiate Actinomyces spp. vs Nocardia spp.?
Actinomyces are:
- Anaerobic
- NOT Acid-Fast
Propionibacterium:
- Gram stain
- Produce what?
- Infection
Diphtheroid morphology
-Propionic Acid production
Skin commensal
-Infections of Prosthetic joint and other foreign bodies
Aerobic Gram+ Bacillus - Spore Forming organisms.
Bacillus spp.
- B. anthracis
- B. cereus
Bacillus spp.:
- Gram stain morphology
- Motile/Nonmotile
- Catalase (+/-)
Gram+ Rods - Large, Rectangular
- Motile
- Catalase POSITIVE
B. anthracis:
- Gram stain
- Colony morphology
- Catalase (+/-)
- Motile/Nonmotile
Forms chains and Subterminal spores
- NonHemolytic w/ irregular borders (Medusa Head colonies)
- Tenacious (stand up when teased with loop)
- Catalase Positive
- NONmotile (semisolid agar; for safety)
B. anthracis - Cutaneous Anthrax.
Most Common
- Least Fatal
- Inoculation of spores in skin wound; handling animals or hides
B. anthracis - Gastrointestinal Anthrax.
Ulcerative lesions
B. anthracis - Inhalation Anthrax.
-Transmission (2)
“Woolsorter Disease”
-Terrorist attacks
B. anthracis - Inhalation Anthrax.
-Characteristic findings
Widened mediastinum (AP CXR) -hemorrhagic mediastinitis
B. cereus:
- Gram stain
- Colony morphology
- Motile/Nonmotile
- Transmission
- Chains w/ Subterminal spores
- BETA-Hemolytic, NONTenacious
- MOTILE
- Asian rice dishes
Aerobic Gram+ Bacillus - NONspore Forming organisms. (6)
- Listeria monocytogenes
- Erysipelothrix rhusiopathiae
- Nocardia
- Rhodoccucus equi
- Corynebacterium diptheriae
- Tropheryma whipplei
Listeria monocytogenes:
- Gram stain
- Colony morphology
- Catalase (+/-)
- Motile/Nonmotile (Temp)
- Semisolid Agar motility test
- Temperature feature
- CAMP test
- Gram+ Rods (singly/short chains)-Short, Nonbranching
- Beta-Hemolysis (narrow zone); Small colonies (1-2 days)
- Catalase POSITIVE
- Motile (best at Room Temp)
- Umbrella-shaped motility
- Can grow at 4C
- CAMP test demonstrates a rectangular zone of enchanced hemolysis
Listeria monocytogenes:
- Pregnant women
- Neonates
- Immunocompromised
- Chorioamnionitis
- Granulomatosis Infantiseptica
- Bacteremia, Meningitis, Encephalitis
Erysipelothrix rhusiopathiae:
- Gram stain
- Motile/Nonmotile
- Catalase (+/-)
- TSI slant feature
- Gram+ Rod, Nonbranching, Coccobacillary or Filamentous
- Nonmotile
- Catalase NEGATIVE
- produces H2S on TSI slants - Blackened Butt (distinguishes from Listeria and Lactobacillus)
Erysipelothrix rhusiopathiae:
- Treatment feature
- Causes?
Vancomycin Resistent (intrinsic) -Erysipeloid - Cellulitis from animal carrier (Anglers, Butchers, Farmers)
Nocardia:
- Gram Stain
- Other Stain
- Best culture medium
- Colony morphology
- Colony Odor
Gram+ Rods (beaded)
- Long, Filamentous, Branching
- Modified Acid-Fast Positive
- BCYE ideal for primary culture
- Chalky white initially then Salmon Orange/Pink when mature
- “Musty Basement” odor
Nocardia Infections. (3)
- Mycetoma (Indolent soft tissue infection)
- Invasive Pulmonary infection
- Disseminated (CNS involvement)
Rhodococcus equi:
- Gram stain
- Location/Cell
- Other Stain
- Colony morphology
- Affects/Cause
- Gram+ Cocci, Coccobacilli, or Coryneform rods
- Histiocytes
- Modified Acid-Fast+ (like Nocardia)
- Slimy/Salmon colored
- Immunocompromised/Pulmonary infection
Corynebacterium diptheriae:
- Gram stain
- Culture medium
- Presumptive ID
- Colony morphology
- Pleomorphic, club shaped (tend to palisade and cluster together)
- Grows well on Blood Agar; Tinsdale agar (improved isolation)
- Reduce Potassium tellurite to Metallic tellurite
- Brown-Black colonies surrounded by Brown Balck halos on Tinsdale agar
Corynebacterium diptheriae:
-Infection
Fever, Sore throat
-Psuedomembrane covering tonsils and other structures
Tropheryma whipplei:
- Where is it found?
- Who gets infections?
- Tissue diagnosis
- Ubiquitous in environment
- Selective immune deficiency; Older Males (M»F)
- Foamy histiocytes; Bacillary organisms PAS Positive (AFB negative)
