Systematic Bacteriology I Flashcards
What 4 categories can microscopy help identify?
Pure culture or polymorph
Shape, size, grouping
Structure
Staining
What are the 3 most common shapes of bacteria?
Cocci (spheres)
Bacilli (rods)
Spiral-shapes
How does coccus create cocci?
Division in one plane of coccus to produce two cocci, division in one plane produces chains of 4-20 cocci or division in 3 planes produces clumps
What type of bacilli can be produced from bacillus?
Bacillus (rod-shaped bacteria) divides into chains of bacilli
Is bacilli chaining more prominent in gram +ve or -ve?
+ve
What type of gram is more common in vibrio (curved rod)?
Gram -ve
How many recognised species of vibrio are there?
34
What 2 types of spiral-shaped bacterium are there?
Rigid - spirillum
Flexible - Spirochaete
How is it easier for spiral shaped bacteria to be motile?
Corkscrew movement through viscous liquid
What are three common structures of bacteria?
Flagella, pili and capsules
How are spores created?
Germination, binary fission, sporulation = prespore, endospore, cell lysis = spore
What is a gram stain?
A simple method that distinguishes two major classes of bacteria according to cell wall structure (gram -ve and gram +ve)
Why would an organism not strain well with Gram stain?
Lipid rich/waxy cell wall that doesn’t take up the stain, or no cell wall at all
BMJ best practice
Dynamed
CDC atlanta
European centre for disease prevention and control
Microbiology resources
What does respiration of obligate anaerobes use instead of oxygen?
Another electron receptor with a smaller reduction potential than oxygen - less proton motive force across membrane (in ATP synthase ) and less energy released per molecule oxidised
What is selective media?
A media that selects for the growth of specific prokaryotes eg Mannitol Salt agar, or salmonella shigella
What does selective media allow?
Presence of a specific substrate permits the growth of one organism over another
What does differential medial allow?
Incorporation of chemicals produces visible changes in colonies that facilitate identification
Eg of differential media?
MacConkay agar and eosi and methylene blue (EMB)
How is Streptococcus identified?
Haemolysis - alpha (greening of the colonies), beta (Lancefield Grouping due to colony size) and gamma (no haemolysis)
What characteristics are looked at in metabolic profiling?
Utilisation of carbon sources, utilisation of amino acids and eco-enzyme production
What characteristics are looked at in metabolic profiling?
Utilisation of carbon sources, utilisation of amino acids and exo-enzyme production
What is a serological test?
Host immune response to antigen by the raising of antibodies. Antibodies specific to microbe/virus (polyclonal) or single component (monoclonal) detect presence of specific IgM Ab
In DNA technology why is a specific primer necessary?
To amplify a specific piece of DNA
