Diagnostic and Typing Methods Flashcards
what are the bacteria associated with periodontal disease?
P. gingivalis
A. actinomycetemcomitans
P. intermedia
B. forsythus
What is the main bacteria associated with dental caries?
S. mutans
what are the main bacteria associated with root canal infections?
P. endodontalis
F. nucleatum
what are the 2 main methods of detecting bacteria?
Microbiological culture
Molecular biological
How does microbiological culture detection identify bacteria?
culture the bacteria on an agar medium, the bacteria is then isolated and identified by doing tests to check the enzyme activities
how does molecular biological detection identify bacteria?
Using DNA probes, and PCR
what are the advantages and disadvantages of the standard culture method of bacteria on petri dishes?
+VE:
yields bacterial isolates for future testing & study (e.g. antibiotic sensitivities)
-VE:
needs viable cells
small numbers of samples can be analysed at once
labour intensive
what is the advantages of PCR?
- highly specific
- sensitive
- can be used to directly detect bacteria in clinical specimens
what are the pros and cons of DNA Probes & PCR?
+VE:
1. less time consuming than culture
2. very sensitive
3. can be used in clinical samples directly
4. does not require viable cells
5. canb detect uncultivable species
-VE:
1. may detect dead cells
2. detect only pre-selected species
what is restriction enzyme analysis (REA) and what problem does it have?
allows you to digest whole genomic DNA using restriction enzymes
problem:
- too many DNA fragments obtained, makes interpretation difficult
what is gene probe typing?
used to identify specific genes by using nucleic acid probes that are complementary sequences to the target gene
What is ribotyping?
molecular biology technique used to classify bacteria based on the unique pattern of ribosomal RNA in their genome
What is DNA sequencing?
allows for determining the exact single base (A, T, C, G) differences between strains of bacteria
