Generalized Info Gram Positive Bacilli Flashcards
What is a bacterial spore?
A small oval structure that forms in bacteria, carrying all the genetic material.
What is an endospore?
A dormant form of a bacterial cell that can survive in poor conditions.
What triggers sporulation in bacteria?
Nutrient depletion, chemicals, heat, and desiccation.
What is the vegetative state in bacteria?
A dividing and germinating state when conditions are favorable.
What is the dormant stage in spore-forming bacteria?
A non-dividing and non-germinating state when conditions are unfavorable.
What is the primary habitat for Bacillus species?
Soil.
What are the two medically important species of Bacillus?
Bacillus anthracis and Bacillus cereus.
What disease is caused by Bacillus anthracis?
Anthrax.
How is anthrax used in biological warfare?
Endospores can be placed in food, water, powder, and spray.
What is the virulence factor of Bacillus anthracis?
Involves toxins (Lethal factor, Edema factor, Protective Antigen) and a capsule.
What are the four forms of anthrax disease?
Cutaneous, pulmonary (inhalation), gastrointestinal, and injectional anthrax.
What is an eschar in cutaneous anthrax?
A painless black necrotic scar that forms after spore exposure.
What are the symptoms of pulmonary anthrax?
Flu-like symptoms progressing to respiratory distress, edema, cyanosis, and shock.
How is gastrointestinal anthrax acquired?
By ingestion of spores, leading to abdominal pain, nausea, vomiting, and bloody diarrhea.
What laboratory test is selective for Bacillus spp.?
PLET (Polymyxin-lysozyme-EDTA-thallous acetate) agar.
What colony appearance does Bacillus anthracis have on blood agar?
Non-hemolytic colonies with a comet tail or Medusa head appearance.
What is the string of pearls reaction?
A characteristic feature of Bacillus anthracis when grown in penicillin-containing medium.
What causes food poisoning associated with Bacillus cereus?
Heat-stable and heat-labile enterotoxins.
What food is commonly associated with Bacillus cereus?
Improperly stored cooked rice (emetic form) and contaminated meat, poultry, or vegetables (diarrheal form).
What is the catalase test result for Bacillus spp.?
Catalase positive.
What disease is caused by Clostridium tetani?
Tetanus.
What are the characteristic symptoms of tetanus?
Lockjaw (trismus), risus sardonicus (grinning), and opisthotonos (back arching).
What is the virulence factor of Clostridium tetani?
Tetanospasmin, a neurotoxin causing muscle spasms.
What is the shape and location of Clostridium tetani spores?
Round and terminal spores giving a drumstick or lollipop appearance.
What is the most potent natural toxin known?
Botulinum neurotoxin produced by Clostridium botulinum.
What are the types of botulism?
Foodborne, infant, wound, and intestinal botulism.
What are the symptoms of botulism?
Double vision, impaired speech, difficulty swallowing, and muscle paralysis.
What is the agent of pseudomembranous colitis?
Clostridium difficile.
What media is used for isolating Clostridium difficile?
Cycloserine-cefoxitin fructose agar (CCFA).
What are the virulence factors of Listeria monocytogenes?
Internalin, phospholipase C, and listeriolysin O.
How is Listeria monocytogenes transmitted?
By ingestion of contaminated food such as unpasteurized dairy products and cold meats.
What is the motility pattern of Listeria monocytogenes in semi-solid medium?
Tumbling motility at room temperature, forming an umbrella-like pattern.
What is the causative agent of erysipeloid?
Erysipelothrix rhusiopathiae.
What is the common occupational group affected by Erysipelothrix rhusiopathiae?
Fish vendors and butchers (seal finger).
What bacteria causes bacterial vaginosis?
Gardnerella vaginalis.
What is the Whiff or Sniff test?
A test for bacterial vaginosis using 10% KOH on vaginal discharge producing a fishy odor.
What is the appearance of clue cells?
Squamous epithelial cells studded with bacteria.
What organism is known as Doderlein bacillus?
Lactobacillus acidophilus.
What is the significance of Lactobacillus in the human body?
Helps maintain an acidic environment in the GIT and vaginal canal, preventing pathogen overgrowth.
What bacteria are associated with Fried Rice Syndrome?
Bacillus cereus.
What is the appearance of Bacillus cereus colonies on PEEMBA medium?
Turquoise or peacock blue colonies due to the bromthymol blue reaction.
What bacteria causes gas gangrene?
Clostridium perfringens.
What are the virulence factors of Clostridium perfringens?
Alpha toxin, enterotoxin, and beta toxin.
What type of hemolysis is characteristic of Clostridium perfringens?
Double zone hemolysis.
What is the reverse CAMP test used for?
Differentiating Clostridium perfringens from other Clostridium species.
What are sulfur granules?
Small, yellowish granules composed of bacteria found in Actinomyces infections.
What organism is known as Klebs-Löffler bacillus?
Corynebacterium diphtheriae.
What is the virulence factor of Corynebacterium diphtheriae?
Diphtheria toxin, which inhibits protein synthesis.
What bacteria has a Chinese letter arrangement in Gram stain?
Corynebacterium diphtheriae.
What test is used for diphtheria susceptibility?
Schick test.
What is the appearance of Corynebacterium diphtheriae on tellurite agar?
Black or brown colonies with a brown halo due to cystinase activity.
