Systemic Bacteriology 1 Flashcards
In what ways are microorganisms classified in terms of appearance?
Shape
Size
Arrangement
Cell wall (gram + or -)
In what ways are microorganisms classified in terms of growth requirements?
Aerobic/anaerobic
Requirement for blood products
Sensitivity to inhibitory proteins
In what ways are microorganisms classified in terms of enzyme or metabolic tests?
Coagulase test, catalase test
Haemolysis
Biochemical profiling
In what ways are microorganisms classified in terms of molecular tests?
Immunological tests
DNA sequencing
Protein profiling
How are microorganisms identified?
Microscopy
What are the most common shapes of bacteria?
Cocci - spheres
Bacilli - rods
Spiral shaped
In what way do cocci divide?
Divide in one plane to produce two cocci
What are the two structures that are produced when cocci divide and how many planes does each divide in?
Chains - one plane
Clumps - three planes
What are bacteria that look like curved rods called?
Vibrio
Are vibrio gram positive or negative?
Negative
What are the two types of spiral shaped bacteria and what are their names?
Rigid - spirillum
Flexible - spirochaete
What is a gram stain?
A simple method that distinguishes the two major classes of bacteria (gram + and -) according to cell wall structure
What are the limitations of gram stains?
Not all organisms stain well with gram stain
What are the examples of organisms that don’t stain well with gram stains?
Mycobacterium tuberculosis Treponema pallidum (causes syphilis)
What are obligate aerobes?
Bacteria that require oxygen
What are obligate anaerobes?
Bacteria that are killed by oxygen
What are facultative anaerobes?
Bacteria that tolerate oxygen
The presence of which specific substances permit the growth of one organism over another?
Mannitol Salt agar (MSS) allows preferential isolation of staphylococci
Salmonella-Shigella (SS) bile salts inhibit coliforms
What are examples of differential media?
MacConkay Agar
Eosin and Methylene Blue
What is a serological test?
A test carried out on a sample of blood seum
What is agglutination?
The clumping of particles that occurs when an antigen is mixed with its corresponding antibody
What may DNA sequencing allow?
Precise identification
What does MLST stand for?
Multilocus Sequence Typing
What is MLST?
A technique for the typing of multiple loci
Why is MALDI-TOF used?
Powerful - 99% correct
Rapid
Precise
Cost-effective
What is the process of MALDI-TOF?
Generates a series of ions from a sample dependent on its constituents
Separates the ions according to mass and charge
Detects the spectrum of proteins released from a sample
Results in a characteristic signature
What are four examples of specific microbiology tests?
Blood culture
Urine culture
Faeces culture
Swab of pus
What are examples of DNA sequencing?
qPCR
16sRNA
