Diagnostic and Typing Methods

Question 1

What bacteria are associated with periodontal disease?

Answer 1

• P. gingivalis
• A.a
• P. intermedia

Question 2

What are the different bacterial detection methods?

Answer 2

• microbiological culture
  
  • Agar
  • isolate bacteria
• Molecular biology
  
  • DNA probes
  • Polymerase chain reaction (PCR)

Question 3

What are the advantages of culture methods?

Answer 3

Yields bacteria isolates for future testing and study e/g/ antibiotic sensitivity

Question 4

What are some disadvanatages of culture methods?

Answer 4

• requires visible cells
• insensitive
• only small numbers of samples can be analysed at once
• inconclusive results
• labour intensive

Question 5

What are DNA probes?

Answer 5

Segments of DNA that have been labelled with chemoluninescent, fluorescent or radioactive agents

Question 6

What are the different types of DNA probes?

Answer 6

• wholw genomic
• cloned gene
• oligonucelotide

Question 7

What are the advantages of PCR?

Answer 7

• highly specific
• sensitive
• can be used to directly detect bacteria in clinical specimens

Question 8

What are the advantages of DNA probes and PCR?

Answer 8

• less time consuming than culture methods
• very sensitive
• can directly detect bacterial DNA within clinical samples
• do not require viable cells, samples dont need to be analysed immediately
• can detect uncultivable sepcies

Question 9

What are the disadvantages of DNA probes and PCR?

Answer 9

• May detect dead cells (might not have actively been involved in an infection)
• detects only pre-selected species