General Bacteriology Flashcards
List properties of prokaryotic cells
No Nucleus, Membrane bound organelles, plasma membrane, cytoskeleton or meiosis. Small diameter
Chemically complex cell wall
Single circular chromosomes
Binary fission
What class of cells are bacteria under?
Prokaryotes
What are 3 exceptions to bacterial properties?
- Mollicutes (Mycoplasma) does not have a cell wall
- Leptospira has two circular chromosomes
- Borrelia burgdorferi has linear chromosomes
What is a unique component about the bacteria cell?
Contains Peptidoglycan
What is a unique cell wall component of Gram + bacteria?
Lipteichoic acid (for antigenicity)
What is a unique cell wall component of Gram - Bacteria?
Outer membrane containing lipopolysaccharide (LPS) (Virulence factor)
What is a unique cell wall component of mycobacteria?
Mycolic acid (Virulence Factor) - Considered gram + bacteria
What is unique about LPS?
Contains a lipid A component that can activate immune system and exert harmful effects on host polysaccharide component and contributes to antigenicity
What is a gram + stain?
Crystal violet because of thick peptidoglycan layer
What is a gram - stain?
Picks up safranin because of think peptidoglycan layer
Acid fast staining is due to the presence of what?
Mycolic acid
What is an acid fast + organism?
Pink (retains carbol fuschin) because of mycolic acid
What is acid fast - organism?
Blue (decolorized) because of lack of mycelia acid
What kind of cell wall do acid fast + bacteria have?
Gram + cell wall
What 3 things can measure bacterial growth?
- Colony
- Turbidimetry
- Flow Cytometry
What kind of bacteria require oxygen for growth?
- Aerobic
- Microaerophillic
- Capnophillic
What kind of bacteria not require oxygen for growth?
- Obligate anaerobe
- Aerotolerant
- Anaerobe
What kind of bacteria don’t require oxygen but can still utilize it for growth?
Facultative Anaerobe
Can bacterial structures enhance the virulence of bacteria?
Yes
Do the presence or absence of bacterial structures facilitate the ID of bacteria?
Yes
What is the function of flagella?
Locomotion or motility
What is the function of Fimbriae or pili?
Adherence
What is the importance of a capsule?
Outer covering that helps bacteria evade phagocytosis
What contain endoflagella/axial filaments?
Spirochetes
What advantage do spores give bacteria?
Help bacteria (Gram +) survive
What are two bacterial virulence factors?
- Exotoxins
2. Superantigens
What are Exotoxins?
Proteins produced by bacteria & released outside to exert action on specific target cell
Majority heat labile
What are endotoxins?
Released when bacteria are dead or killed
Can induce inflammation by stimulating immune system
Heat stable
What are superantigens?
Produced by pathogenic microbes
Binding to MHC class II on APCs and T helper cell receptor
Result in polyclonal T cell activation and massive cytokine release
How does biofilm form?
Microbes cling to surface and produce EC substances and take in nutrients
Slowly grow and cause imbalance
How do bacteria use quorum sensing?
When population reaches certain level, changes occur and culminate in infection and overwhelm immune system defenses
How do bacteria and fungi cause disease?
Pathogenesis
What is pathogenesis?
Mechanism by which pathogen cause disease
What is virulence?
Degree of pathogenicity, includes severity
Are most bacteria pathogens?
No
What two things mediate virulence transfer of Bacteria?
Via Plasmids and Bacteriophages that carry genes for antibiotic resistance, toxins, capsules, and fimbriae
How are bacteria virulence factors transferred?
Via conjugation, transformation, and transduction
What 5 things increase virulence?
- Fimbriae
- Flagella
- Capsule
- Quorum sensing
- Biofilm formatin
What are the sequence of events in bacterial or fungal pathogenesis?
- Host entry
- Evade host defense
- Colonize host system
- Multiply
- Exert damage in host
- Transmit to other hosts = INFECTIOUS
How do bacteria and fungi cause disease?
- Deplete host nutrients
- Toxins
- As a result of immune response to microbe
What are fungi?
- Eukaryotes
- Heterotrophs
- Absorptive nutrition
- Asexual repro/some sexual repro
- Plant-like cell wall
- Unicellular or multicellular
- Free-living
- Infections less common than bacterial infections
