Reintro to Microbiology Flashcards
Name the major types of microorganisms
- Eukaryotic - protazoa and fungi
- Fungi
- Bacteria - prokaryotes
- Viruses
- Prions - infectious proteins
Protozoa features?
Unicellular eukaryotes 2-100μm Many are free living e.g. Malaria Often affect the immunocompromised Mainly a threat in developing countries
Fungi features?
Eukaryotic organisms with a variety of forms
Commercially important- baking, brewing
External, rigid cell wall- containing chitin
Filamentous or yeast forms
Many are dimorphic = ability to have 2 lifestyles
e.g. Candida
Bacteria features?
Most numerous organisms
Adapted to inhabit almost all habitats
- Even those not based on sunlight- deep sea vents
Responsible for PLAGUE
Produce a range of toxins- virulence factors
Specialised cell walls
Prokaryotes - no internal membranous compartments
How to classify bac?
- Cellular form
- Cocci (1)
- Diplococci (2)
- Tetrads (4)
- Sarcina (4 behind 4)
- Streptococci (wiggly)
- Staphylococci (kite shape)
Baclli:
Branching
Extended irregular rods
Kidney bean
Corkscrew
Helical - Cell wall structure
- Gram positive - 1 membrane = fuzzy part is peptidoglycan layer = retains stain = purple
- Gram neg - 2 membranes and thin cell wall between the 2 = perioplasmic space = do not retain stain = pink/red stain
What is a peptidoglycan?
A polymer of N-acetyl muramic acid (NAM) and N-acetyl glucosamine (NAG)
Crosslinked via AA pentapeptides and anchored to cell wall
What surface structures do bac have?
Flagellum = allows movement
Pili and fimbriae;
- Proteinaceous filamentous structures
- Used for attachment to host cells or surfaces
- Adhesins at the tip for host interaction
- Used for twitching motility
- Pseudomonas spp.
What are pathogens? Example?
Disease causing bac e.g. Vibrio cholera - cholera
What are opportunistic pathogens?
Commensals that sometimes cause disease e.g. MRSA, N.meningitis
Where are commensals located? How much is there?
Main mass in digestive tract
1kg mass in bac
What are commensals?
Unseen hordes - mainly harmless, colonise surfaces and mucosa
What makes mycobacteria different?
Have a normal membrane, peptidoglycan and mycolic acids = more resistant = unusual cell well
Features of mycobacterium spp? Example of a mycrobacterium?
Gram pos rods, unusual cell wall - mycolic acid
Impervious to gram staining
Zeen Ziehl-Neelson acid fast staining procedure; mycobacteria in red
E.g M. tuberculosis
M.leprae significance? E.g of mycobacterium
First bac clinically associated with a disease - leprosy
Treated with antibiotics
What causes chlamydia? Histological Features, Life Cycle Features? What does chlamydia cause?
Organism : C.trachomatis Histology: Unusual gram neg cell wall Life Cycle: Unusual life cycle - elementary body facilitates spread, reticulate body (intracellular replication) Clinically: Urethral and vaginal infec Conjunctivitis Infertility and ectopic pregnancies
