Day2 Flashcards
What spp. is described?
- frequent lab contaminants
- widely distributed, particularlysoil
- large, GPR , square ended spore forming
- Colonies are spreading, dry, granular, gray-green and usually beta
Non pathogenic Bacillus spp.
Bacillus spp that can cause food poisoning but usually non pathogenic
Bacillus cereus
Bacillus spp that is usually a contaminant (non pathogenic)
Bacillus subtilis
What organism is the primary human pathogen in the Bacillus genus ?
Bacillus anthracis
Why is the military concerned about B.anthracis?
It has a potential to be used as a biological weapon
Describe the appearance of B.anthracis spores
Ellipsoidal to cylindrical centrally located spore
What organism is described: frequently long chains, bamboo or “box car” appearance.
Bacillus anthracis
Why is motility and hemolysis particularly important when differentiating between Bacillus spp.
- Bacillus anthracis is non-motile; other species are motile
- Bacillus anthracis is gamma hemolytic; other species are usually beta
What gives bacillus anthracis its virulence?
Encapsulated and toxin-producing
Describe Pulmonary Anthrax.
Woolsorter’s disease, spores INHALED during shearing, sorting or handling of animal hair or skin
Describe Gastrointestinal Anthrax
Most rare; bacilli or spores gain entrance into the body when swallowed or ingested
Describe Cutaneous Anthrax
Infection initiated by entrance of bacilli through abrasions in the skin
What extreme caution must be taken when handling Bacillus anthracis?
Using Bacteriological safety hood
Another name for Corynebacterium spp?
Diptheroids
What organism is described:
- gram positive slender pleomorphic rods
- colonies are ORANGE to CREAM in color
- GARLIC odor
- Non pathogenic; NF of skin and mucous membranes
Corynebacterium spp.( Diptheroids)
Describe Corynebacterium diphtheriae.
- small Gram positive
- very pleomorphic, slender bacilli
- found in CHINESE LETTER or PALISADES configuration
What are the 3 subspecies of Corynebacterium diphtheriae?
Gravis
Intermedius
Mitis
What do the three subspecies of Corynebacterium diphtheriae all have in common?
They all cause “Diphtheria”
What are the three types of media used for Corynebacterium diphtheriae?
BAP
Loeffler’s Serum
Cystine-Tellurite
Purpose of Loeffler’s Serum Media?
promotes the pleomorphic appearance; enhances identification of meta chromatic granules
Purpose of Cystine-Tellurite?
Allows for colony morphological differentiation of subspecies
Describe colony of C.diphtheriae mitis.
small black shiny convex round beta hemolytic
Describe colony for C.diphtheriae intermedius.
Small
Flat
Non hemolytic
Describe colony of C.diphtheriae gravis.
Large
Dark grey center
Brittle
Non hemolytic
What are the symptoms of diphtheria? What causes them?
Soreness in throat, pharynx and larynx; followed by myocarditis and neuritis caused by and EXOTOXIN
True or false:
Corynebacterium spp. are motile
False, they are non motile
What is Elek?
Toxin testing used to differentiate pathogenic Corynebacterium diphtheriae from non pathogenic
What is used to ID Corynebacterium diphtheriae?
Toxin testing(Elek) and Carbohydrate testing
What organism is a major pathogen of the Listeria spp. and is most often encountered in clinical lab?
Listeria monocytogenes
What diseases does Listeria monocytogenes cause?
- Nonspecific febrile illness in pregnant women, which may lead to stillbirths
- Meningitis in adults
- Sepsis and/or meningitis in neonates
Describe motility of Listeria spp.
25 degrees Celsius= umbrella motility
37 degrees Celsius= non-motile
What are the characteristics of Lactobacillus spp?
Catalase neg
Non-motile
Non-spore forming
Facultative anaerobes or microaerophilic
True or false:
Lactobacillus is Normal flora of the oral, intestinal and vaginal tract.
True
What disease does Lactobacillus cause?
- Usually non pathogenic
- isolated in cases of endocarditis, septicemia and meningitis
- Frequent contaminant in urine cultures
Describe hemolysis characteristics of Listeria spp.
Narrow zone of beta hemolysis
What is characteristic about the morphology/ gram stain of Gardnerella vaginalis?
resembles a gram negative bacilli but has the cell wall of a gram positive organism; appears GRAM VARIABLE
Why is Gardnerella vaginalis considered to be marker of bacterial vaginosis rather than a causative agent?
Gardnerella vaginalis can be part of many women’s normal flora.
What is a clue cell?
Epithelial cells covered by gram variable bacilli
What organism considered to be a veterinary pathogen ?
Erysipelothrix rhusiopathiae
What organism causes a cellulitis-like lesion on the hands?
Erysipelothrix rhusiopathiae
What organism cannot be clinically distinguished from BSGA?
Arcanobacterium haemolyticus
What organism produces toxins: Phospholipase D and Hemolysin, and the enzyme Neuramindase?
Arcanobacterium haemolyticus
What organism was formerly classified in the genus Corynebacterium?
Arcanobacterium haemolyticus