Bacteriology Part II Flashcards
Classification of bacteria:
- genotype and phenotype
- staining properties (gram/acid)
- metabolism (aerobic, anaerobic, microaerophilic)
- biochemical, fatty acid profile
- 16s gene sequencing, whole genome sequencing
How to write bacterial name?
Bacillus anthracis (italicized)
Phylogeny is based on what factors of bacteria? (evolutionary relationship between bacteria)
- sequences of bacteria (DNA, RNA, Protein)
- 16s ribosomal gene used the most
Are most bacteria harmful?
no, most are beneficial or harmless
There are more microbial cells (10^14) than human cells (10^13)
True
Microbial cells are collectively called:
Microbiome
What is pathogenesis?
How bacteria cause disease
How do bacteria cause disease?
disease occurs due to complex interactions between the host, pathogen, and the environment
What is a pathogen?
a microorganism that has the potential to cause disease
What is an infection?
the invasion, and multiplication of a pathogen in an individual or population
What is disease?
when the infection causes damage to the individual’s vital functions or systems
Does an infection always result in disease?
NO
Does the microbe have to enter the body to cause infection?
YES
What is the site that they enter called?
Portal of entry
What 4 sites can the microbe enter through?
1) Skin
2) Mucous membranes of Respiratory tract
3) GI tract
4) Urogenital tract
What are exotoxins? (virulence factor)
proteins that are produced by the bacteria and excreted to perform action on target cells
- are HEAT LABILE (can be destroyed by heat)
What are endotoxins? (virulence factor)
- Lipid A component of LPS
- can be harmful
Characteristics of endotoxins:
1) Heat stable
2) Part of bacterial cell wall
3) released when bacteria is dead or killed
4) Can stimulate the immune system and inflammation
What are superantigens?
produced by pathogenic microbes
What do superantigens bind?
They connect/ bind MHC II molecules on antigen presenting cells to T helper cells
What is the response of superantigen binding?
1) T cell activation
2) cytokine release
What physical response may you see with superantigen binding?
nausea, vomiting, fever, shock
What are the virulence factors? (3)
1) Exotoxins
2) Endotoxins
3) Superantigens
How bacteria transfer virulence factors?
1) Plasmids
2) Bacteriophages
- these guys carry info for capsules and resistance etc
