Flashcards in Gram Pos Bacilli Exam 2 Deck (38)
What organisms are of interest in this section?
Bacillus, Corynebacterium, and Listeria
Which Bacillus species are not considered normal flora?
B. cereus, B. circulans, B. licheniformis, B. subtilis
Bacillus spp. characteristics?
Large, Gram + Rods
Most are motile, ferment glucose, catalase +
Bacillus anthracis general characteristics?
Encapsulated (inhibits phagocytosis)
Disease of livestock
**Causative agent of anthrax in humans**
ID for Bacillus anthracis?
Colonies- large, opaque, green-gray to white, tenacious
**Ground glass appearance MEDUSSA HEAD**
What is the BS level done on Bacillus anthracis for preliminary testing?
Confirmative ID at reference labs are Level 3
What are the 3 human forms of anthrax?
Cutaneous-malignant pustule, typically not fatal.
Pulmonary or Woolsorter's disease- inhale spores (rare-usually fatal).
Gastrointestinal- ingestion of contaminated meat (rarest form, fatal 25-60% of the time).
Anthrax is contagious or not contagious?
Not contagious from person to person
What is the treatment of anthrax?
Resistant to penicillin
What is associated with Bacillus cereus? What is the preferred specimen?
*The food itself*
ID for Bacillus cereus?
Lavender colonies with slight green tinge on SBAP
Beta hemolytic, catalase +, motile
Bacillus stearothermophilus is used for?
Control organism in autoclave effectiveness
List and describe the agents of bioterrorism.
Category A- highest risk to public health (Clostridium botulinum, Bacillus anthracis, Yersinia pestis).
Category B- have moderate to low mortality rates (Brucella spp.).
Category C- emerging pathogens.
What is Listeria and Corynebacterium characteristics?
Gram pos rods
Both are facultative anaerobes
What is the transportation of Listeria monocytogenes?
Ingestion of raw vegetables, contaminated dairy and food products.
*Has been documented to cross the placenta from mother to the developing fetus.*
What are the virulence factors of Listeria monocytogenes?
Listeriolysin O- pore forming capabilities. Has hemolytic and cytotoxic capabilities.
Internalin- induces phagocytosis (gets in cells).
Act A- induces cellular extensions on phagocytic cells that are infected with microbe. Helps spread microbe.
What are Listeria monocytogenes characteristics?
Beta hemolysis. White, smooth translucent. Bile esculin+
Gram pos rods to coccobacilli in pairs or chains. Don't confuse with Group A or B beta-hemolytic Streptococci.
What is the incubation of Listeria monocytogenes?
30-35 degrees C
What is the treatment for Listeria monocytogenes?
What is the presumptive ID for Listeria monocytogenes?
End over end tumbling motility.
Umbrella shaped motility pattern via stab in semi-solid agar.
*If isolate small gram positive rod, catalase pos, with narrow zone of beta hemolysis, suspect L. monocytogenes.*
How can L. monocytogenes can be differentiated from other Listeria spp.?
A positive CAMP test or Hippurate test
How to prevent Listeria monocytogenes spread?
Wash raw produce, don't cut raw meats on wood cutting board with veggies, wash your hands, and keep fridge at 40 degrees F or lower.
General characteristics of Corynebacterium spp.?
Non-motile, non-acid fast, and pleomorphic
**Resemble Chinese letters**
Which Corynebacterium spp. is not considered normal flora?
True/false? Diphtheriods are often considered normal flora and include C. diphtheriae.
False. Normal flora, but does NOT include C. diphtheriae
What does the "Chinese letters" appearance come from?
Irregular snapping during cell division
What is selective media that can be used for Corynebacterium spp.?
Cystine tellurite media- brown halo
Tinsdale agar- gray-brown halo
Which biotype is the most severe and virulent in Corynebacterium spp.?
Which organism has metachromatic granules?
Methylene Blue stain allows for visualization.