COMMON BACTERIAL PATHOGENS Flashcards
(35 cards)
What is cultivation in microbiology?
The process of growing organisms in vitro (in an artificial environment) and not in their actual in vivo site.
What are fastidious microorganisms?
Bacteria that require specific and complex nutritional and environmental conditions to grow.
What do nutritional media provide for microbial growth?
Essential nutrients required for the cultivation of microorganisms, including a balanced mixture of carbon, nitrogen, vitamins, minerals, and other growth factors.
What is basic (simple) media used for?
Supports the growth of non-fastidious organisms.
Give an example of enriched media.
Blood agar, Chocolate agar.
What is selective media?
Contains specific inhibitors to suppress unwanted microbes while promoting the growth of target bacteria.
What does differential media do?
Helps distinguish between different microorganisms based on biochemical reactions.
What is transport media used for?
Maintains microbial viability without allowing significant growth during transport.
What characteristics are examined for the morphological identification of bacterial colonies?
Size, shape, color, texture, and other visible characteristics on a solid growth medium.
What is the purpose of the Gram stain?
A differential staining technique used to classify bacteria into two major groups: Gram-positive and Gram-negative.
What is a key feature of Gram-positive bacteria?
They have a thick peptidoglycan layer that retains the primary stain (crystal violet).
What distinguishes Gram-negative bacteria?
They have a thin peptidoglycan layer and an outer membrane, which does not retain crystal violet after decolorization.
What are the characteristics of Enterobacteriaceae?
- Aerobes or facultative anaerobes
- Ferment glucose
- Oxidase negative
- Reduce nitrates to nitrites
Which bacteria are considered lactose fermenters?
Escherichia, Klebsiella, Enterobacter, Citrobacter.
Which bacteria are considered non-lactose fermenters?
Salmonella, Shigella, Proteus, Pseudomonas.
What is the morphology of Escherichia coli?
Gram negative short rods, motile, some strains are capsulated.
What diseases can E. coli cause?
- Urinary tract infections
- Diarrheal diseases
- Sepsis in newborns
What is the significance of Klebsiella pneumoniae?
It can cause destructive changes in the lungs if aspirated, despite being a normal inhabitant of the mouth, intestine, and respiratory tract.
What diseases are caused by Klebsiella pneumoniae?
- Lobar pneumonia
- Urinary tract infections
- Bacteremia
What is the morphology of Salmonella?
Gram negative, motile rods, non-capsulated.
What disease is caused by Salmonella?
Enteric fever.
What is the morphology of Mycobacterium tuberculosis?
Straight or slightly curved rods.
What is the cultural characteristic of Mycobacterium tuberculosis?
They grow on enriched media as Lowenstein-Jensen medium forming off-white colonies.
What diseases does Mycobacterium tuberculosis cause?
Human tuberculosis.
