Gram Positive Bacilli

Question 1

Spore-forming Anaerobic Gram+ bacilli indicates what species?

Answer 1

Clostridium spp.

Question 2

Clostridium perfringens:

• Gram Stain
• Blood Agar
• Prelim ID requires what?

Answer 2

Gram+ Rods (short chains)

• Large, “Boxcar-shaped”
• Double-zone B-Hemolysis
• Lecithinase activity

Question 3

Clostridium septicum:

• Gram Stain
• Blood agar
• Bacteremia association

Answer 3

Gram+ Rod (Large; forms chains)

• Swarming (not discrete colonies)
• Colonic adenocarcinoma/GI pathology

Question 4

Clostridium botulinum:

• Diagnosis
• Common source?

Answer 4

• Toxin detection (serum, stool, vomit)

- Raw honey (infant botulism)

Question 5

Clostridium tetani:

-Diagnosis

Answer 5

Clinical Diagnosis

-NO lab tests for toxin available

Question 6

Clostridium dififcile:

• Culture medium/condition
• Colony morphology
• Gram stain
• Culture “odor”

Answer 6

• 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

Question 7

Clostridium difficile:

-Molecular detection

Answer 7

Toxin A and Toxin B genes

Question 8

Clostridium difficile:

-ELISA

Answer 8

Glutamate Dehydrogenase (GAD)*
-More sensitive than stool Toxin

*Ag produced by C. diff

Question 9

What C. difficile strain is associated with Severe C. diff colitis?

Answer 9

BI/NAP1/027 strain

Question 10

PCR is able to detect C. difficile 027 strains; what mutations is found?

Answer 10

tcdC gene mutation

Question 11

What are the NONspore-forming Anaerobic Gram+ bacilli species? (2)

Answer 11

• Actinomyces spp.

- Propionibacterium

Question 12

Actinomyces spp.:

• Gram stain (*Identical to what other organism?)
• Colony morphology

Answer 12

Gram+ Rods - Branching/Filamentous
-White Cerebriform (Molar Tooth) colonies (A. israelii)

*Nocardia spp.

Question 13

How do you differentiate Actinomyces spp. vs Nocardia spp.?

Answer 13

Actinomyces are:

• Anaerobic
• NOT Acid-Fast

Question 14

Propionibacterium:

• Gram stain
• Produce what?
• Infection

Answer 14

Diphtheroid morphology
-Propionic Acid production
Skin commensal
-Infections of Prosthetic joint and other foreign bodies

Question 15

Aerobic Gram+ Bacillus - Spore Forming organisms.

Answer 15

Bacillus spp.

• B. anthracis
• B. cereus

Question 16

Bacillus spp.:

• Gram stain morphology
• Motile/Nonmotile
• Catalase (+/-)

Answer 16

Gram+ Rods - Large, Rectangular

• Motile
• Catalase POSITIVE

Question 17

B. anthracis:

• Gram stain
• Colony morphology
• Catalase (+/-)
• Motile/Nonmotile

Answer 17

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)

Question 18

B. anthracis - Cutaneous Anthrax.

Answer 18

Most Common

• Least Fatal
• Inoculation of spores in skin wound; handling animals or hides

Question 19

B. anthracis - Gastrointestinal Anthrax.

Answer 19

Ulcerative lesions

Question 20

B. anthracis - Inhalation Anthrax.

-Transmission (2)

Answer 20

“Woolsorter Disease”

-Terrorist attacks

Question 21

B. anthracis - Inhalation Anthrax.

-Characteristic findings

Answer 21

Widened mediastinum (AP CXR)
-hemorrhagic mediastinitis

Question 22

B. cereus:

• Gram stain
• Colony morphology
• Motile/Nonmotile
• Transmission

Answer 22

• Chains w/ Subterminal spores
• BETA-Hemolytic, NONTenacious
• MOTILE
• Asian rice dishes

Question 23

Aerobic Gram+ Bacillus - NONspore Forming organisms. (6)

Answer 23

• Listeria monocytogenes
• Erysipelothrix rhusiopathiae
• Nocardia
• Rhodoccucus equi
• Corynebacterium diptheriae
• Tropheryma whipplei

Question 24

Listeria monocytogenes:

• Gram stain
• Colony morphology
• Catalase (+/-)
• Motile/Nonmotile (Temp)
• Semisolid Agar motility test
• Temperature feature
• CAMP test

Answer 24

• 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

Question 25

Listeria monocytogenes: - Pregnant women - Neonates - Immunocompromised

Answer 25

- Chorioamnionitis - Granulomatosis Infantiseptica - Bacteremia, Meningitis, Encephalitis

Question 26

Erysipelothrix rhusiopathiae: - Gram stain - Motile/Nonmotile - Catalase (+/-) - TSI slant feature

Answer 26

- Gram+ Rod, Nonbranching, Coccobacillary or Filamentous - Nonmotile - Catalase NEGATIVE - produces H2S on TSI slants - Blackened Butt (distinguishes from Listeria and Lactobacillus)

Question 27

Erysipelothrix rhusiopathiae: - Treatment feature - Causes?

Answer 27

``` Vancomycin Resistent (intrinsic) -Erysipeloid - Cellulitis from animal carrier (Anglers, Butchers, Farmers) ```

Question 28

Nocardia: - Gram Stain - Other Stain - Best culture medium - Colony morphology - Colony Odor

Answer 28

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

Question 29

Nocardia Infections. (3)

Answer 29

- Mycetoma (Indolent soft tissue infection) - Invasive Pulmonary infection - Disseminated (CNS involvement)

Question 30

Rhodococcus equi: - Gram stain - Location/Cell - Other Stain - Colony morphology - Affects/Cause

Answer 30

- Gram+ Cocci, Coccobacilli, or Coryneform rods - Histiocytes - Modified Acid-Fast+ (like Nocardia) - Slimy/Salmon colored - Immunocompromised/Pulmonary infection

Question 31

Corynebacterium diptheriae: - Gram stain - Culture medium - Presumptive ID - Colony morphology

Answer 31

- 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

Question 32

Corynebacterium diptheriae: | -Infection

Answer 32

Fever, Sore throat | -Psuedomembrane covering tonsils and other structures

Question 33

Tropheryma whipplei: - Where is it found? - Who gets infections? - Tissue diagnosis

Answer 33

- Ubiquitous in environment - Selective immune deficiency; Older Males (M>>F) - Foamy histiocytes; Bacillary organisms PAS Positive (AFB negative)