Microbiology Flashcards

1
Q

Any cell that possesses a clearly defined nucleus is known as

A

A Eukaryote

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2
Q

Cells that lack a nucleus and other organelles are known as

A

Prokaryotes

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3
Q

A type of protein that causes disease by triggering abnormal folding of usually normal healthy proteins

A

Prions

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4
Q

Define an opportunistic pathogen

A

An organism that causes infection when opportunity/change in natural immunity arises e.g. in an immunocompromised individual

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5
Q

An organism that grows in a culture by accident is known as

A

A contaminant

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6
Q

The capacity of a microbe to cause damage to the host

A

Virulence

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7
Q

Define an exogenous infection

A

Infective material deriving from outside the body

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8
Q

Define an endogenous infection

A

Deriving from inside the body e.g. commensal bacteria, transfer from non-sterile to sterile site

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9
Q

What communities of bacteria are most prevalent on gingiva

A

Streptococci
Actinomyces

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10
Q

What communities of bacteria are most prevalent on the palate

A

Streptococci
Actinomyces

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11
Q

What communities of bacteria are most prevalent on the tooth surface

A

VERY COMPLEX
Streptococci
Neisseria
Actinomyces
Veillonella
Fusobacterium

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12
Q

What communities of bacteria are most prevalent on the tongue

A

Streptococci
Haemophilius
Veilonella

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13
Q

What communities of bacteria are most prevalent on the cheek

A

Streptococci
Actinomyces
Haemophilius

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14
Q

What communities of oral bacteria are most prevalent in the gingival crevice

A

VERY COMPLEX
Streptococci
Actinomyces
Gram negative anaerobic cocci and rods
Gram positive anaerobic cocci and rods

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15
Q

What community of bacteria dominates the oral cavity?

A

Streptococci

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16
Q

Where is streptococcus mutans most commonly found in the oral cavity?

A

Saliva and approximal plaque

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17
Q

Define approximal

A

Where contact points meet

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18
Q

Where is streptococcus sanguinis most commonly found in the oral cavity?

A

Tongue, saliva, approximal and subgingival plaque

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19
Q

Where is Actinomyces spp, most commonly found in the oral cavity?

A

Saliva, approximal and subgingival plaque

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20
Q

Define virulence factor

A

A component of a pathogen that contributes to it’s ability to cause disease

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21
Q

Name five main virulence factors

A
  1. Adhesin
  2. Invasin
  3. Impedin
  4. Aggressin
  5. Modulin
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22
Q

What is the function of adhesin

A

Enables binding of an pathogen to host tissue

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23
Q

What is the function of invasin

A

Enables invasion of host tissues

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24
Q

What is the function of impedin

A

Enables pathogen to avoid host defence mechanisms

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25
Q

What is the function of aggressin

A

Causes damage to host directly

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26
Q

What is the function of modulin

A

Causes indirect damage to host (via immune system)

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27
Q

Explain the route of infection of oral streptococci spread that could cause endocarditis

A
  1. Strep gain access to bloodstream
  2. Pathogens rapidly adhere via platelet fibrin deposition
  3. Some species can obtain intra cellular access
  4. Heart function impaired
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28
Q

Give some examples of bacterial mechanisms to evade host defence

A
  • immunity at mucosal surfaces
  • destroy immune cells
  • interfere with inflammatory response
  • evade innate immunity
  • overcome acquired immune responses (change antigens)
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29
Q

What is the defining characteristics of gram-ve bacteria?

A

Outer membrane and lipopolysaccharide layer

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30
Q

Main role of gram-ve bacteria’s outer membrane

A

Binds to receptors on macrophages, B cells and other cells that stimulates release of acute phase cytokines

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31
Q

Define Koch’s Postulates

A

Four criteria designed to establish a casual relationship between a microbe and a disease

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32
Q

Anaerobes that cannot tolerate oxygen are known as

A

Strict anaerobes

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33
Q

Anaerobes that can survive with the presence or abscence of oxygen are known as

A

Facultative anaerobes

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34
Q

Define pericoronitis

A

Inflammation of soft tissues surrounding the crown of a partially erupted tooth

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35
Q

Define dental alveolar abscess

A

Localised collection of pus in the alveolar bone at the apex of tooth root

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36
Q

What type of anaerobe is streptococci angionosus?

A

Facultative

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37
Q

What type of anaerobes is prevotella spp. ?

A

Strict

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38
Q

What type of anaerobe is fusobacterium nucleatum?

A

Strict

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39
Q

What type of cell wall does strep anginosus have?

A

Gram positive

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40
Q

What type of cell wall does prevotella spp. have?

A

Gram negative

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41
Q

What type of cell wall does fusobacterium nucleatum have?

A

Gram negative

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42
Q

What bacterial community is mainly associated with dental abscess’

A

Streptococci anginosus

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43
Q

What bacterial community is mostly associated with gingivitis/periodontitis?

A

Prevotella spp.

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44
Q

What does GNAB stand for?

A

Gram negative anaerobic bacteria

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45
Q

What is often the cause of endodontic infections?

A

Pulpitis and recurrent infection following root canal treatment

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46
Q

What bacteria is associated with primary endodontic infections?

A

Streptococcus

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47
Q

What bacteria is common in recurrent endodontic infections?

A

Enterococcus faecalis (gram +ve)

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48
Q

What type of anaerobe is enterococcus faecalis?

A

Facultative

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49
Q

What bacteria can survive in very alkaline conditions, such as in calcium hydroxide and sodium hypochlorite treatment?

A

Enterococcus faecalis

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50
Q

Define ‘dry socket’

A

Localised infection following extraction where socket fails to heal

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51
Q

What bacteria are commonly associated with implantitis?

A

Streptococcus aureus
Streptococcus epidermis

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52
Q

What bacterium are associated with pulpitis/ root canal treatment failure?

A

Fusobacterium
Enterococcus

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53
Q

What bacteria is associated with dry socket?

A

Fusobacterium

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54
Q

What bacteria is involved in the diversification of plaque, and is also found in supra and sub gingival plaque?

A

Actinomyces

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55
Q

What bacteria is associated with root surface caries?

A

Actinomyces

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56
Q

What type of Actinomyces is described as very aggressive

A

Actinomyces Israelii

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57
Q

Where can the treponema bacterial group most commonly be found in the oral cavity?

A

At the base of teeth

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58
Q

What bacterium is commonly associated with chronic perio lesions?

A

Treponema denticola
P. Gingivalis

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59
Q

What bacteria is commonly isolated from moist sites (e.g. the scalp, ears, Genito-urinary tract)

A

Staphylococcus

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60
Q

What type of cell wall does staphylococci aureus have?

A

Gram positive

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61
Q

What type of cell wall does staphylococci epidermis have?

A

Gram positive

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62
Q

Where is staphylococci aureus usually found?

A

In the nose

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63
Q

Where would staphylococcus epidermis usually be found?

A

In the skin and mucous membranes

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64
Q

Is staphylococcus aureus coagulase positive or negative?

A

Coagulase positive

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65
Q

What would coagulase positive indicate in a test?

A

Presence of staphylococci aureus

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66
Q

Coagulase is a virulence factor of staphylococcus aureus? True or false?

A

True

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67
Q

Is staphylococci epidermis coagulase positive or negative?

A

Coagulase negative

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68
Q

Is there a working vaccine available for staph aureus? Yes or no

A

No

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69
Q

What bacteria is a leading causative agent in pneumonia and other respiratory tract infections?

A

Staphylococcus aureus

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70
Q

What bacteria is associated with toxic shock syndrome?

A

Staphylococcus aureus

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71
Q

What skin infections are associated wit staph aureus?

A
  • rash
  • folliculitis
    -abscess
  • impetigo
  • scalded skin syndrome
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72
Q

What is a superantigen?

A

Class of antigens that result in excessive activation of the immune system

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73
Q

What is the superantigen associated with toxic shock syndrome?

A

TSST-1

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74
Q

How does TSST-1 influence toxic shock syndrome?

A

It is a virulence factor that has the ability to overstimulate the immune system

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75
Q

Name two very important virulence factors of staphylococcus aureus

A
  1. Fibrinogen binding protein
  2. Coagulase
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76
Q

What are the two main roles of coagulase?

A
  1. Promote conversion of fibrinogen to fibrin and clotting
  2. Assists deposition of fibrin on surface and prevents phagocytes recognising them
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77
Q

What does PVL stand for?

A

Panton- Valentine Leukocidin

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78
Q

What is PVL?

A

A cytotoxin

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79
Q

What cell does PVL have a specific toxicity for?

A

Leukocytes

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80
Q

What infections is PVLA mainly associated with?

A

Sever skin infections and necrotising pneumonia

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81
Q

What antibiotic is used to treat severe staph infections such as MRSA

A

Vancomycin

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82
Q

What does MRSA stand for?

A

Methicillin resistant staphylococcus aureus

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83
Q

What salivary gland infections is S. aureus usually assorted with?

A

Acute bacterial parotitis

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84
Q

What antibiotics are used to treat acute bacterial parotitis?

A

Co-amoxyclav
Flucloxacillin

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85
Q

What is another term for group A streptococci?

A

Streptococcus pyogenes

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86
Q

What’s type of cell wall does strep pyogenes have?

A

Gram positive

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87
Q

Destruction of red blood cells is known as

A

Haemolysis

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88
Q

What is the type of haemolysis with largest risk?

A

Beta haemolysis

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89
Q

What type of haemolysis does strep pyogenes undergo?

A

Beta haemolysis

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90
Q

What does GAS stand for?

A

Group A Streptococcus

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91
Q

Where is strep pyogenes most commonly found?

A

Throat and skin

92
Q

Examples of disease associated with GAS

A

-impetigo
-cellulitis
-necrotising fasciitis
-acute streptococcal gingivitis

93
Q

What is rheumatic fever?

A

Inflammatory condition affecting various parts of the body, usually a following complication of strep throat

94
Q

What are the symptoms of bacterial sore throat

A

-nausea
-vomiting
-stomach ache

95
Q

What are the symptoms of viral sore throat

A

-cough
-swelling in throat
-runny nose

96
Q

What type of sore throat is more severe? Bacterial or viral?

A

Bacterial

97
Q

Define scarlet fever

A

Severe form of strep throat with associated rash ( caused by strep pyogenes)

98
Q

What antibiotics can be used to treat strep pyogenes infection

A

Pen V
Amoxicillin
Erythromycin

99
Q

What are the major virulence factors associated with strep pyogenes

A
  • M protein
  • Hyaluronic acid
100
Q

Which virulence factor of Strep pyogenes plays a role in evasion of the immune system?

A

M protein

101
Q

Name the important bacteria associated with upper respiratory tract infections

A
  • streptococcus pyogenes
  • bordetella pertusis
  • corynebacterium diphtheria
  • haemophilus influenza
102
Q

What bacteria is most commonly found in upper respiratory tract infections?

A

Streptococcus pyogenes

103
Q

What bacteria causes whooping cough?

A

Bordatella pertusis

104
Q

What type of bacteria is bordatella pertusis?

A

Small gram -ve cocci

105
Q

In what group of individuals does whooping cough most often present?

A

Children

106
Q

What are the characteristics of whooping cough?

A

Highly contagious
Life threatening
Severe cough lasting 2-3 weeks

107
Q

What antibiotic ( and for how long) is often used to treat whooping cough?

A

Erythromycin for 14 days

108
Q

How does bordatella pertusis present in the respiratory tract?

A

Attaches to ciliates epithelial cells

109
Q

What promotes the attachment of bordatella pertusis to epithelial cells in the respiratory tract?

A

Virulent proteins

110
Q

What is the key toxin associated with bordatella pertusis?

A

Tracheal cytotoxin (TCT)

111
Q

What type of bacteria is corynebacterium diphtheria?

A

Gram +ve bacilli

112
Q

What structures of the upper respiratory tract are effected by diphtheria?

A

Throat and pharynx

113
Q

What is the characteristic clinical appearance of diphtheria?

A

Swollen neck (medical emergency)

114
Q

What is the immediate treatment required to treat diphtheria?

A

Inoculation with diphtheria antitoxin

115
Q

What antibiotics are used to treat diphtheria?

A

Penicillin or erythromycin

116
Q

What type of bacteria is haemophilius influenza?

A

Gram -ve bacilli

117
Q

What bacteria can cause both upper and lower respiratory tract infections?

A

Haemophilius influenza

118
Q

What form of Haemophilius influenza is the most significant cause of mortality?

A

Capsule type B ( Hib)

119
Q

What is the benefit of a capsule surrounding bacteria?

A

It protects bacteria from phagocytosis

120
Q

what are the important bacteria associated with lower respiratory tract infections?

A
  • Haemophilius influenza
  • streptococcus pneumoniae
  • mycobacterium tuberculosis
121
Q

Acute inflammation of the lungs often caused by streptococcus pneumoniae is known as?

A

Pneumonia

122
Q

Define lobar pneumonia

A

Bacteria has travelled deep into lungs and alveoli

123
Q

What type of cell wall does streptococcus pneumoniae have?

A

Gram +ve

124
Q

What bacteria does optochin identify?

A

Streptococcus pneumoniae

125
Q

What is the importance virulence factor associated with strep pneumoniae called?

A

Pneumolysin

126
Q

what complex capsular type of strep pneumoniae has made vaccine development difficult?

A

Alpha- haemolytic streptococcus

127
Q

What are the three important symptoms of strep pneumoniae infection?

A

-abrupt onset
-high fever
-severe pain

128
Q

What type of cell wall does myobacterium tuberculosis have?

A

Gram +ve

129
Q

How does oral tuberculosis present?

A

As secondary lesions found at the back of the mouth

130
Q

What is the importance of myobacterium tuberculosis’ ‘waxy cell wall’?

A

It allows survival in the atmosphere and prevents desiccation

131
Q

What is the primary antibiotic used to treat tuberculosis?

A

Isoniazid

132
Q

Isoniazid is used to treat tuberculosis, what other antibiotic can be used?

A

Rifampicin

133
Q

What is the importance of legionella pneumphilia in dental practices?

A

This bacteria lives in water supplies. Highlights the importance of dental waterline management.

134
Q

What is the main oral streptococci that causes dental caries?

A

Streptococci mutans

135
Q

What strep bacteria is responsible for dental abscesses?

A

Strep anginosus

136
Q

What type of cell wall do majority of cariogenic bacteria have?

A

Gram +ve

137
Q

What are the main features of strep mutans, as a cariogenic bacteria?

A
  • binds to and colonises plaque on tooth surface
  • acidogenic ( producing acid at a fast rate from sugar)
  • acidification ( surviving at a low pH as they can tolerate high concentrations of acid)
138
Q

What bacteria has the largest number of genes associated wit sugar transport and utilisation?

A

Strep mutans

139
Q

What surface proteins of S.mutans are important for colonisation and attachment?

A

Antigen I/II, Glucosyl transferase and Lucan binding protein

140
Q

What surface protein of S.mutans is key for it’s attachment to biofilm?

A

Antigen I/II

141
Q

What are the four main lactic acid producing oral microbes?

A
  • oral streptococci
  • lactobacilli spp.
  • Actinomyces spp.
  • Rothia denticariosa
142
Q

Which pathogenic oral microbe is associated with progression of carious lesions?

A

Lactobacilli spp.

143
Q

What bacteria has historically been reported as associated with root surface caries?

A

Actinomyces spp.

144
Q

What cariogenic role does rothia dentocariosa have?

A

Colonises supra- gingival plaque

145
Q

What is the ecological plaque hypothesis (put simply)?

A

Communities may be more or less susceptible to becoming dysbiotic (not everyone gets caries under the same circumstances)

146
Q

What potential does veillonella have as a beneficial member of the oral microbiome?

A

High numbers of veillonella in dental plaque are thought to raise the plaque pH and reduce cariogenic its of plaque

147
Q

What are the two different types of interaction that can present in dental biofilm?

A

Co-operative ( synergistic/ beneficial) and competitive ( antagonist/ inhibitory)

148
Q

The substance released by one bacteria that kills another usually by inducing metabolic block is known as?

A

Bacteriocin

149
Q

What is quorum sensing?

A

The process of cell-cell communication that allows bacteria to share information about cell density and adjust gene expression accordingly

150
Q

What are the main factors that influence the biofilm environment colonised by S. mutans?

A
  • extracellular polymeric substances
  • DNA
  • bacteriocins
  • quorum sensing molecules
151
Q

What are the main virulence factors of cariogenicity?

A
  • adhesion
  • acidogenicity
  • acid tolerance
152
Q

What bacteria is commonly associated with pulpitis?

A

Enterococcus

153
Q

What bacteria are often associated with caries?

A

Streptococcus, lactobacilli, fusobacterium etc.

154
Q

What bacteria are usually associated with periodontal conditions?

A

GNAB’s, anginosus group prevotella, and porphyramonas

155
Q

What bacteria has resistance issues and is commonly seen in head and neck infections again and again?

A

Prevotella

156
Q

What bacteria is commonly found to be associated with dry socket?

A

Treponema denticola

157
Q

How would you treat dry socket with antibiotics?

A

Use of metronidazole

158
Q

What bacteria is associated with implantitis?

A

Staphylococcus

159
Q

Which plaque hypothesis is applicable to gingivitis?

A

Non-specific plaque hypothesis

160
Q

Why type of bacteria (cell wall) dominate in supra and subgingival disease?

A

Gram +ve

161
Q

What type of bacteria (cell wall) are more abundant subgingivally compared to supragingivally?

A

Gram -ve

162
Q

What is the name of the group of gram -ve anaerobes that dominate subgingivally?

A

GNAB’s

163
Q

Name the three most abundant bacteria sub-gingivally

A
  1. Streptococci
  2. Actinomyces
  3. Eubacterium
164
Q

What did the pioneering studies of Loe investigate?

A

The relationship between plaque and gingivitis

165
Q

What were the two key findings of the studies of loe?

A
  • gingivitis develops with the appearance of supra-gingival dental plaque
  • gingivitis resolves with loss of supra-gingival plaque
166
Q

What were the four key conclusions found in the studies of loe?

A
  1. Ceasing OH leads to plaque build up and gingivitis
  2. OH allows for gingivitis to reverse and healthy gingivae to be restored
  3. Chlorohexidine could remove plaque and return gingiva to health
  4. With plaque accumulation, more gram -ve anaerobic bacteria was present
167
Q

How many plaque hypotheses are there?

A

Three

168
Q

The hypothesis that states: “dental caries was an infection with specific bacteria in the dental plaque, of which most were mutans streptococci.”

A

Specific plaque hypothesis

169
Q

The plaque hypothesis that states: the idea that the accumulation of dental plaque was responsible for oral disease, with no single organism being responsible.

A

Non-specific plaque hypothesis

170
Q

The plaque hypothesis which states: disease is a result of an imbalance in micro flora due to ecological stress.

A

Ecological plaque hypothesis

171
Q

Which gram-ve anaerobe is largely involved in the pathogenesis of periodontitis?

A

Porphyramonas gingivalis

172
Q

Which gram -ve facultative anaerobe is associated with localised aggressive periodontitis?

A

Aggregatibacter actinomycetemcomitans

173
Q

What are the key characteristics of periodontal disease?

A
  • true pockets develop
  • LOA
  • bone resorption
  • condition becomes irreversible
174
Q

What pathogens are associated with chronic periodontitis?

A

Porphyramonas gingivalis, fusobacterium nucleatum and spirocheates

175
Q

What pathogens are associated with rapidly progressive periodontitis?

A

Porphyramonas gingivalis, prevotella intermedia and fusobacterium nucleatum

176
Q

What did socransky do in 1998?

A

Assayed for presence of 40 species of bacteria through DNA-DNA hybridisation

177
Q

What was the result of socransky’s study?

A

Produced a red and orange complex of bacteria found in deep perio pockets

178
Q

What three bacteria are the most abundant in the red section of socransky’s study?

A
  • P. Gingivalis
    -T. Forsythia
    -T. Denticola
179
Q

Certain low-abundance microbial pathogens that can bring about inflammatory disease by turning a normally benign microbiota into a dysbiotic one, are known as?

A

Keystone pathogens

180
Q

What are endotoxins and their main function?

A

Components of Gram-ve bacterial wall with their main function being structural and protective

181
Q

How does nitrogen metabolism counter development of a low pH environment?

A

Produces ammonia (alkaline) from protein breakdown in plaque

182
Q

Bacteria shown to significantly contribute to periodontitis are known as?

A

Periopathogens

183
Q

Name the 6 key periopathogens

A

P. Gingivalis
T. Forsythia
Prevotella
Fusobacterium nucleatum
T. Denticola
Aggregatibacter actinomycetemcomitans

184
Q

Which periopathogen is metronidazole ineffective against?

A

Aggregatibacter actinomycetemcomitans

185
Q

Which antibiotic reduces periopathogens and red/orange complex bacteria?

A

Metronidazole

186
Q

What antibiotic in combination with metronidazole would be more effective in the treating sub-gingival disease and why?

A

Amoxicillin, would allow for effective treatment against A. Actinomycetemcomitans

187
Q

What are the tow therapies used to treat sub-gingival disease?

A

Antibitoics
Mechanical plaque removal

188
Q

What pathogen depends on host cells for reproduction?

A

Virus

189
Q

What are the two structures of viruses?

A

Enveloped an non-enveloped

190
Q

What are virus particles composed of?

A
  • nuclei acid genome
    -protein capsid
  • lipid envelope ( depending on structure)
191
Q

Which virus has significance in oral and cervical cancer?

A

Papillomavirus (HPV)

192
Q

Why do RNA viruses tend to form quicker than DNA viruses and what are the implications of this?

A

Because RNA is more unstable. This increases chance of mutations.

193
Q

What are the three main problems associated with viruses?

A
  • latency
  • chronic/persistent infection
  • cancer
194
Q

What does treatment for viruses include?

A

Anti-viral drugs
Vaccines

195
Q

What is vertical transmission?

A

Transmission from mother to child

196
Q

What herpatic virus is associated with disease of pre-school children?

A

Primary gingivostomatitis

197
Q

How would you treat primary gingivostomatitis?

A

With acyclovir

198
Q

Describe latency of Herpes

A

Latency after primary infection is where the inactive from of the virus lives in sensory nerve cells (trigeminal ganglia) and can reactivate to re-infect mucosal surfaces

199
Q

How many different antibiotics can GDP’s prescribe?

A

14

200
Q

Why is pen V a more appropriate choice of antibiotic compared to amoxicillin?

A

Pen V has a narrower spectrum

201
Q

What are antibiotics?

A

Drugs used to treat or prevent infections caused by micro-organisms

202
Q

Why are antibiotics used?

A

To control/limit the impact of bacterial disease

203
Q

What is antibiotic resistance?

A

The ability of bacteria to escape the action of antibiotics

204
Q

Define bacteriostatic

A

Inhibit growth of bacteria

205
Q

Define bactericidal

A

Kill bacteria

206
Q

What beta lactam narrow spectrum antibiotic is active against gram +ve bacteria

A

Penecillin

207
Q

what are features of an ideal antibiotic?

A
  • selective toxicity/ minimal toxicity to host
  • bactericidal
  • long half-life
  • appropriate tissue distribution
  • no adverse drug interactions/ side effects
208
Q

what part of bacterial cells does antibiotics mainly target?

A

Cell wall and ribosomes

209
Q

What are limitations of penicillins?

A
  • patients can be allergic
  • rapid excretion results in frequent dosage daily
  • resistance
210
Q

Can co-amoxiclav be used on its own?

A

No, it does not have antibiotic properties by itself, should always be paired with another antibiotic

211
Q

What antibiotics target protein synthesis?

A
  • doxycycline
  • erythromycin
  • clindamycin
212
Q

What group of antibiotics is useful for treating infections where bacteria ‘hide’ from the host’s immune system?

A

Macrolides ( e.g. erythromycin)

213
Q

How is metronidazole activated?

A

Activated in cytoplasm by reduction under anaerobic conditions ( e.g. damages DNA)

214
Q

what antibiotic is active against anaerobes and some parasites?

A

Metronidazole

215
Q

What are the 4 main antibiotics prescribed by dentists? in order of most popularly used.

A
  • amoxycillin (67%)
  • metronidazole (27%)
  • Erythromycin (3%)
  • Pen V (1%)
216
Q

What are the two types of antibiotic resistance?

A

Natural and acquired

217
Q

What is the subpopulation of cells that resist treatment and become antimicrobial TOLERANT by changing to a state of dormancy?

A

Persistor cells

218
Q

What is horizontal gene transfer (HGT)?

A

A resistance gene can be passed within species by HGT thus spreading resistance

219
Q

What should you always aim to use before antibiotics as a gdp?

A

Local measures

220
Q

What is empiric prescribing?

A

Broadly targeting a condition when unsure exactly what is causing the issue

221
Q

What does metronidazole interact badly with?

A

Alcohol

222
Q

What infection do broad spectrum antibiotics increase the risk of?

A

C. Difficile

223
Q

What can over-prescribing result in?

A
  • drug resistance
  • overgrowth/infection by other microbes
  • contribute to evolution of pathogens
  • reduce colonisation resistance
224
Q

What are two local measures that should be considered before antibiotics are prescribed?

A
  • extraction
  • incision and drainage of pus
225
Q

What bacteria can have a healthy effect on the oral cavity, by breaking down food, absorbing nutrients and fighting off other harmful bacteria?

A

Lactobacilli