L30,31: normal microflora of the mouth

Question 1

which part of the oral cavity acts as a reservoir for obligate anaerobes ?

Answer 1

the tongue

Question 2

what gram positive cocci are present in the oral cavity ?

Answer 2

genus streptococcus
genus stomatococcus
genera staphylococcus and micrococci

Question 3

sub groups of genus streptococci and how they affect the oral cavity :

Answer 3

S. mutans : causes carries , could be responsible for infective endocarditis

S.mitis : forms dental plaque , biofilm , dental carries , and could also be responsible for infective endocarditis

S.amginosus :affects gingival crevice , causes dentoalveolar and endodontic infections

Question 4

all genus streptococcus grow in which aerobic conditions ?

Answer 4

facultative anaerobes

Question 5

what selective media do genus streptococci grow in ?

Answer 5

mitis salivarius agar

Question 6

which group of gram positive cocci are emerging pathogens in neutropenic patients ?

Answer 6

genus stomatitis

Question 7

what gram positive bacilli are part of the normal flora in the oral cavity ?

Answer 7

-genus actinomyces :\
-eubacterium
-lactobaccilli
-propionibacterium

Question 8

what are the different species of actinomyces and what are their effects on the oral cavity ?

Answer 8

A. odontolyticus : demineralization of enamel and progression of small caries lesions

A.naeslundii: root surface carries and gingivitis , most common representative in plaque

A.israelli: causes cervicofacial and ileocaecaol actinomycosis

Question 9

what bacilli is the most common representative in plaque formation ?

Answer 9

actinomyces naeslundii

Question 10

eubacterium aerobic conditions :

Answer 10

anaerobic

Question 11

which organism is responsible for corncob formation in dental plaque ?

Answer 11

eubacterium yurri

Question 12

which organism is the pioneer in advancing front of carious process especially in dentine ?

Answer 12

lactobacilli

Question 13

aerobic conditions needed for lactobacilli to grow ?

Answer 13

microaerophillic

Question 14

aerobic conditions needed for propionibacterium to grow? how does it affect the oral cavity ?

Answer 14

anaerobic

implicated in root surface carries and formation of plaque biofilms

involved in dentoalveolar infections

Question 15

what gram negative cocci are present in the normal flora of the oral cavity ?

Answer 15

genus Neisseria : diplococci , facilitative anaerobe

genus veillonella : strict anaerobe
both are not associated with disease

Question 16

facilitative anaerobes/ capnophillic gram negative bacilli in oral cavity :

Answer 16

genus haemophilius : grows on blood agar , -facultative anaerobe

genus aggregatibacter : often isolated from cervicofacial actinomycosis as co-pathogen , microaerophillic / capnophillic

genus eikenella : chronic periodontitis . infective endocarditis , plaque , dentoalveolar abscesses ,-microaerophillic

genus Capnocytophaga : gliding motility
plaque , mucosal surface and saliva infections in immunocompromised patients,-capnophilic

Question 17

main species of genus eikenella ?

Answer 17

eikenella corrodens

Question 18

obligate anaerobe gram negative bacilli in oral cavity :

Answer 18

genus pophyromonas

genus fusobacterium

Question 19

what kind of pigments does genus pophyromonas have on blood agar?

Answer 19

dark pigments

Question 20

where is P.gingivalis often isolated from ?

Answer 20

subgingival sites especially in advanced periodontitis

Question 21

which gram negative bacilli is an aggressive periodontal pathogen ?

Answer 21

genus porphyromonas

Question 22

shape of genus fusobacterium :

Answer 22

cigar shaped

Question 23

main species of genus fusobacterium :

Answer 23

f. nucleatum

Question 24

fusobacterium , in combination with oral spirochets cause :

Answer 24

fusospirochoetal infections : vincents angina , acute ulcerative gingivitis , cancrum oris

Question 25

what oral protozoa are present in the oral cavity ?

Answer 25

trichomonas tenax

entamoeba gingivalis