Bacteriology Introduction Flashcards
What are the 4 phases of bacterial growth?
- Lag
- Logarithmic growth
- Stationary
- Death
What are the 3 bacterial shape classifications?
- Coccus
- Rod
- Spirillum
What are obligate aerobes?
Bacteria that require oxygen for growth
What are obligate anaerobes?
Where oxygen is toxic for bacterial growth
What are facultative anaerobes?
Bacteria that can use oxygen if present, but can also grow without it
What are aerotolerant anaerobes?
Bacteria that do not use oxygen but it is not toxic
What are microaerophiles?
Bacteria that grow best with low levels of oxygen
What are the two general types of bacteria?
- Gram-positive (purple)
- Gram-negative (pink)
What are mycobacterias?
A type of acid-fast bacteria
What are mycoplasmas?
A type of bacteria that does not have a cell wall
What are peptidoglycans?
Bacterial cell walls that is rigid and prevent osmotic lysis.
What does the glycan backbone alternate?
G and M (M can form cross-linkages)
What is lipid A?
A molecule that is comprised of disaccharides and fatty acid groups. They are recognized by the innate immune system which leads to septic shock.
What is the nucleoid?
- not the ‘nucleus’
- does not have a surrounding membrane
- have a single, circular chromosome (most but not all bacteria)
- haploid genomes
What are plasmids?
- Extrachromosomal genetic elements
- Usually not required for bacterial growth
- Often encode for ‘fitness’ factors (antibiotic resistance)
- can be transferred from bacteria to bacteria
What are that 3 types of host-microbe relationships
- Commensalism
- Mutualism
- Parasitism
What is commensalism?
Where one benefits without helping or hurting the other
What is mutualism?
Where both benefits (the host and the microbe)
What is parasitism?
Where one benefits (microbe) at the expense of the other (host)
What makes bacterial pathogens successful?
- Colonization
- Invasion/toxicity
- Immune evasion
- Transmission
- Pathogens produce virulence factors (molecules produced by the pathogen that contribute to disease)
What are the different types of virulence factors?
- LPS (endotoxin)
- Flagella
- Pili and adhesins
- Capsules
- Secretion system
- Exotoxins
What are flagella?
Structures that allow some bacteria to be motile (chemotaxis)
What are Pili?
Structures that are primarily involved in attachment to surfaces, host tissue, and other bacteria
What are capsules?
- Usually made up of (exo) polysaccharides
- Attachment to host tissues
- Protection form host immune system
- Can sometimes be used in vaccines
- Formation of biofilms
What are the 4 stages of biofilms?
- Attachment
- Microcolony development
- Biofilm development
- Maturation
What are endospores?
- Highly differentiated cells formed within the parent cell
- Highly resistant to heat, harsh chemicals and radiation
- A “dormant” stage of the bacterial life cycle
What are exotoxins
- Secreted from bacteria
- Includes hemolysins, toxins that function inside host cells, extracellular enzymes and superantigens
What bacterial secretion may be used as a vaccine when they are inactivated?
Exotoxins
How can some bacteria become intracellular pathogens?
- They were taken up by a macrophage and survived within it
- some ‘force’ their own uptake into epithelial cells
- allows bacteria to hide from different components of the immune system
