Microbiology

Question 1

what forms can the cell wall be in?

Answer 1

gram positive or negative

Question 2

what is LPS?

Answer 2

gram negative outer membrane

Question 3

what are flagella?

Answer 3

found in gram positive and negative - enables bac to swim

Question 4

where are fimbriae found?

Answer 4

gram negative

Question 5

what is a pathogen?

Answer 5

microbe capable of causing host damage

Question 6

what can staph aureus cause?

Answer 6

MRSA
abscesses
carbuncle
folliculitis
impetigo

Question 7

what does strep pyogenes?

Answer 7

strep sore throat

Question 8

what are types of gm +ve bacteria?

Answer 8

strep - facultative/obligate anaerobes
staph - facultative
actinomyces
lactobacillus

Question 9

describe strep mutans?

Answer 9

binds to tooth surface and causes tooth decay
intitiates caries at enamel surface
bind and colonise tooth surface and produce sticky extracellular polysaccharides
produce acid from sugar
tolerate acidic conditions

Question 10

what is infective endocarditis caused by?

Answer 10

strep sanguinis

Question 11

describe lactobacilli?

Answer 11

pleomorphic rods
acidogenic/aciduric pH 5.5
produces lactic acid from glucose 
levels in saliva correlate with carbohydrate intake 
cause dentinal caries

Question 12

describe actinomyces?

Answer 12

pleomorphic rods
anaerobic and facultative
fimbrae aid in adherence 
supra and sub plaque 
root surface caries
abscess and dentoalveolar infections

Question 13

what are GNABS?

Answer 13

gram negative anaerobic bacilli

Question 14

what are non motile GNABS?

Answer 14

bacteriodes
porphyromonas
prevotella
tannerella
fusobacterium

Question 15

in a healthy perio pocket what bacteria are present?

Answer 15

gm positive

Question 16

describe porphyromonas?

Answer 16

dark purple pigmented bacteria GNAB- use ecxternal haeme as iron source. iron scavenging molceules at surface = dark appearance
assachorylitic - produce proteases to breakdown amino acids and peptides
present in sulcus and perio pocket
associated with perio

Question 17

describe prevotella?

Answer 17

dark purple
non saccharolytic
sulcus and perio pocket

Question 18

describe tannerella?

Answer 18

saccharolytic non pigmented bacteria
fibrinogen binding BspA
proteases produced

Question 19

what is BspA?

Answer 19

induced bone resorbing pro inflammatory cytokines

Question 20

describe fusobacterium?

Answer 20

endotoxins - perio disease
in gingival sulcus
binds with treponema to form fusospirochaetal infection

Question 21

what is aggregatibacter?

Answer 21

present in gingival sulcus and perio pocket

leukotoxin, collagenases, proteases

Question 22

what is plaque?

Answer 22

a biofilm - bacterial cells enclosed in extracellular matrix

Question 23

what is in the organic matrix of plauqe?

Answer 23

host and bacterial products

gingival proteins

Question 24

what is present in the pellicle?

Answer 24

acidic prp
amylase
albumin
statheirn
lysozyme
immunoglobulin

Question 25

how does the pellicle develop?

Answer 25

contact
attachment
adhesion
growth
co aggregation
microcolony formation
biofilm forms
climax community

Question 26

what is the bacterial developnment of the plaque?

Answer 26

1. strep
2. joined and replaced by actinomyces
3. gram negative species replace e.g fusobacterium

Question 27

what types of bacterial adhesion take place?

Answer 27

cell substratum
homotypic
heterotypic - corn cob/test tube

Question 28

what is a virus?

Answer 28

nucleic acid genome
protein capsid - protection
poss lipid envelope + virus proteins

Question 29

what does hep b cause?

Answer 29

malaise

jaundice and liver disease

Question 30

what is HIV?

Answer 30

a retorovirus
reverse transcriptase
replicates in cells with CD4 marker

Question 31

Smutans is responsible for?
comes in what forms?
what metabolic pathway do they account for?

Answer 31

dental caries
rods, cocco bacilli
make extracellular polysaccharides from sucrose, convert these to acids

Question 32

form of actinomyces?
involved in what dentally?
what metabolic pathway are they involved in?

Answer 32

gram positive rods and filaments
plaque, gingivitis, root surface caries
produce lactic acid from glucose

Question 33

lactobacillus is the cause of?

produce what from glucose?

Answer 33

caries of dentine

lactic acid

Question 34

Aggregatibacter actinomyctecomitans is the cause of?
form?
what does it stimulate?
produces what?

Answer 34

aggressive forms of periodontal disease in adolescents
stimulates bone resorption
leukotoxins, collegenase, proteases

Question 35

porphyromonas gingivalis commonly seen in what?
why is it black pigmented?
fibrous capsule because?
how does it attach?
what does it produce?

Answer 35

advanced periodontal lesions
requires external haem source as energy
evades host response
fimbrae
collagen degrading enzymes, proteases

Question 36

prevotella seen when?

Answer 36

perio disease

Question 37

what is fusobacterium?
commonly seen in?
asaccharolytic or saccharolytic?

Answer 37

gram negative anaerobe
periodontal disease
asaccharolytic

Question 38

prevotella is pigmented?

found where?

Answer 38

yes

perio pocket and sulcus

Question 39

tannerella is pigmented? saccharolytic or asaccharolytic?

produces what?

Answer 39

saccharolytic
non pigmented
fibrinogen binding BspA and proteases

Question 40

fusobacterium often found where?
releases what that contributes to perio disease?
causes a fusospirochaetal infection by binding with?

Answer 40

sulcus
releases endotoxins
binds with treponema