diagnostic and typing methods

Question 1

name 3 bacteria associated with periodontal disease

Answer 1

p.gingivalis
prevotella intermedia
tanerella forsythia

Question 2

what is the main bacteria implicated in dental caries

Answer 2

streptococcus mutans

Question 3

name a bacteria that may be implicated in root canal infections

Answer 3

porphyromonas endontalis

Question 4

microbiological culture methods of bacterial detection

Answer 4

traditional method
bacteria are grown on a suitable agar medium then isolated and identified

Question 5

what 3 tests can be done once bacteria have been isolated from agar to identify them

Answer 5

• anaerobes can be detected using metronidazole disc ( this kills anaerobes)
• gram stain (gram positive stain dark purple)
• Rapid API 32A - kit allowing identification from enzyme activity and sugar fermentation profile of bacteria

Question 6

disadvantages of using microbiological culture methods for bacteria detection

Answer 6

labour intensive, requires viable cells, relatively insensitive, only small numbers of samples can be analysed at once, often inconclusive results

Question 7

name two types of molecular biological methods of bacteria detection

Answer 7

DNA probes
PCR
PCR - RFLP

Question 8

DNA probes

Answer 8

single stranded sequence of DNA that searches for its complementary sequence within a sample
probes are labelles which an agent e.g fluorescent

Question 9

what is the probe type of choice if doing DNA probing

Answer 9

oligonucleoride probes. - small size making them very specific

Question 10

what gene do all bacteria process

Answer 10

16S ribosomal gene
contains 9 variable regions that contain unique DNA sequences for each individual bacteria

Question 11

polymerase chain reaction

Answer 11

exponential amplification procedure whereby a single molecule of DNA can be amplified billions of times to produce a large amount

Question 12

name 3 advantaged to using molecular biological methods of bacterial detection compared with microbiological culture methods

Answer 12

less time consuming
very sensitive
dont require viable cells
dont need to be analysed immediately
can directly detect bacteria from within clinical samples

Question 13

molecular typing

Answer 13

identifying different strains of micro organisms by looking at their genetic material

Question 14

what is the ultimate typing method

Answer 14

DNA sequencing

Question 15

name 4 methods of collecting a specimen from a patient

Answer 15

smear (scrape)
oral rinse
swab
biopsy