Aerotolerant Gram Positive Bacillius Flashcards
Gram positive bacillus group
2 Bacillus species 2 Corynebacterium species Listeria monocytogenes Erisipelothrix rhusiopathiae Lactobacillus Garderella vaginalis
Bacillus species
B. anthracis
B. cereus
The two main pathogens of Cornyebacterium species
C. diptheriae
C. jeikium
Bacillus gram stain
Spore forming large GPB
Are Bacillus species motile?
Yes, almost all species
What environmental conditions suit Bacillus species?
Aerobic or Facultative anaerobes
What the Catalase reaction of Bacillus?
Catalase positive
Hemolysis reaction of Bacillus?
Many are beta hemolytic
Where do Bacillus organisms reside?
Most are saphrophytic (feeds on dead tissue) to the skin and can b found in the environment
What ability makes Bacillus resistant to extreme temperatures?
They are spore formers.
Bacillus anthracis pathology and virulence?
Anthrax
- Cutaneous anthrax is acquired from handling livestock
- Pulmonary anthrax is called woolsorter’s disease
- Agent of bioterrorism
- Requires level 3 safety hood
Bacillus anthracis colony morphology?
Medusa head colonies
What is the motility of Bacillus anthrax?
Non-motile
What type of hemolysis does Bacillus anthracis have?
Non-hemolytic
Bacillus cereus pathology
Food poisoning
Two types of food poisoning causes by Bacillus cereus?
- Preformed emetic toxin (mostly from rice)
- Later onset-caused by spores that are not inactivated by cooking or pasteurization and germinates in the body releases enterotoxin
Listeria infections occur when humans?
Eat contaminated food, especially processed meat and dairy.
Listeria is unique b/c?
It can grow at 4 C, thus it grows in the fridge.
Listeria growth on BAP resembles…..
Group B Strep–milky colonies with slight beta hemolysis
What is catalase reaction for listeria?
Positive
What is listeria’s relationship to oxygen?
Facultative anaerobic
How does listeria escape the immune system?
By living in our cells
GPB that creates a pseudomembrane in the throat
Corynebacterium diphtheriae
How is C. diptheriae transmitted?
respiratory droplets
Corynebacterium diphtheriae growth on BAP?
usually slightly beta hemolytic, but not always
Loeffler media can used to vizualize?
metachromatic granules
Potassium tellurite media shows Corynebacterium diphtheriae as?
gray to black colonies
How is Corynebacterium diphtheriae treated?
anti-toxin
Most people are vaccinated against which Corynebacterium?
Corynebacterium diphtheriae
Disease process of Corynebacterium diphtheriae?
Produces diptheria exotoxin that leads to formation of the pseudomembrabe in oropharynx before the toxin goes on to damage the heart and other organs
Does Corynebacterium diphtheriae have a carrier state?
Can be carried by healthy individuals.
What type of hemolysis does Bacillus cereus have?
beta hemolytic
What is the colony morphology of Bacillus cereus?
usually gray to lavender in color and can vary greatly in size and shape
Nickname for Corynebacterium jeikeium?
JK
Corynebacterium jeikeium infects what patient most commonly?
Generally after broad spectrum antibiotic use
Where do people most commonly become infected with Corynebacterium jeikeium?
Generally a nosocomial infection and not common.
What type of infections does Corynebacterium jeikeium cause?
Causes wound infections as well as septicemia.
How does Corynebacterium jeikeium respond to antibiotics?
Very resistant
How does Corynebacterium jeikeium grow on BAP?
pinpoint white colonies
What air conditions does Corynebacterium jeikeium prefer?
Likes increased CO2
Corynebacterium catalase reaction and relations to O2?
Catalase positive and Aerobes or facultative anaerobe
Where in the environment are Corynebacterium found?
They are normal inhabitants of skin and mucous membranes of humans.
Do Corynebacterium produce spores?
No.
Corynebacterium on gram stain?
GNB that are pleomorphic and form “Chinese letters” and or “picket fences”
Where are Lactobacillus found?
Found in the environment and soil.
Normal flora of the human oropharynx and vaginal canal.
Lactobacillus is what type of ingredient in food?
Probiotic
What is the clinical significance of Lactobacillus?
Usually non-pathogenic.It should be the primary organism on vaginal specimens, alteration in pH can affect the environment leading to overgrowth of other organisms. It tolerates pH 3-4 and produces lot of lactic acid.
What is the catalase reaction of Lactobacillus?
negative
What is the Gram stain appearance of Lactobacillus?
Long, thin GPB
How is Erysipelothrix rhusiopathiae acquired?
Generally by a veterinarian or meat handler infection of the skin
Erysipelothrix rhusiopathiae catalase reaction?
negative
Erysipelothrix rhusiopathiae gram stain?
Thin GPB that sometimes chains
decolorizes easily
Erysipelothrix rhusiopathiae BAP growth?
yes.
ususally non-hemolytic
Erysipelothrix rhusiopathiae H2S reaction?
Positive
Gardnerella vaginalis gram stain?
Pleomorphic and gram variable
Unusual cell wall composition
Clue cells can be see from a patient swab
Gardnerella vaginalis disease?
bacterial vaginosis–very smelly grey discharge
Vaginal pH is altered >4.5
Gardnerella vaginalis enivironment?
can be normal vaginal flora in small amounts
Gardnerella vaginalis growth on BAP?
very small, pinpoint non-hemolytic colonies
Gardnerella vaginalis air preference?
Grows better with increased CO2
Listeria can look like what type of strep on a plate?
Group B strep agalactiae