Microbiology And Antimicrobials Flashcards
1
Q
What type of bacteria is Streptococcus Angiosus?
A
Gram Positive Cocci
2
Q
Give an example of a gram positive cocci bacteria:
A
Streptococcus Anginosus
3
Q
What type of bacteria is Veillonella Species?
A
Gram Negative Cocci
4
Q
What is an example of a gram negative cocci bacteria?
A
Veillonella Species
5
Q
What type of bacteria is Actinomyces Israeli?
A
Gram Positive Bacilli
6
Q
What is an example of a Gram Positive Bacilli bacteria?
A
Actinomyces Israelii
7
Q
What is an example of a Gram Negative Bacilli bacteria?
A
Prevotella Intermedia
8
Q
What type of bacteria is Prevotella Intermediate?
A
Gram Negative Bacilli
9
Q
What type of bacteria is Prevotella Intermediate?
A
Gram Negative Bacilli
10
Q
What is the meaning of an Aerobic Growth condition?
A
Growth in the presence of Oxygen
11
Q
What is the meaning of a Capnophilic growth condition?
A
Growth in the presence of Carbon Dioxide
12
Q
What is the meaning of a facultative growth condition?
A
With and Without oxygen
13
Q
What is the meaning of Strictly Anaerobic growth conditions?
A
Without oxygen
14
Q
Which growth condition for bacteria does metronidazole have effect?
A
Strictly Anaerobic
15
Q
Which growth condition for bacteria does metronidazole have effect?
A
Strictly Anaerobic
16
Q
What is the definition of Antimicrobial Resistance?
A
Occurs when microorganisms such as bacteria, viruses, fungi and parasites change in ways that render the medications used to cure the infections they cause ineffective
17
Q
What is the definition of Antimicrobial Resistance?
A
Occurs when microorganisms such as bacteria, viruses, fungi and parasites change in ways that render the medications used to cure the infections they cause ineffective
18
Q
What are the two types of resistance?
A
Intrinsic and Acquired
19
Q
What are two examples of acquired resistance?
A
Mutation and Acquisition of new DNA
20
Q
What is an example of resistance by altered target site?
A
S.mitis
Penicillin resistance due to modified penicillin binding proteins
21
Q
What is an example of antibiotic resistance?
A
Enzymatic Inactivation
22
Q
What two species of bacteria demonstrate resistance by enzyme inactivation?
A
Prevotella and Fusobacterium
23
Q
Define: Endogenous Infection
A
The infectious agent is derived from the host flora
24
Q
What is the ideal specimen for a dental abscess?
A
Pus Aspirate
25
Why is a pus aspirate the ideal sample for a dental abscess?
Prevents contamination with saliva
26
What are the treatment principles for a localised infection?
Establish a diagnosis and document it
Remove the source of infection
27
Which two bacterias are commonly associated with dental abscesses?
Streptococcus Anginosus
Prevotella Intermedia
28
Which two bacterias are commonly associated with Periodontal Abscesses?
Anaerobic Streptococci
Prevotella Intermedia
29
Which bacterias are associated with Pericoronitis?
Mixed oral Anaerobes (P Intermedia)
S Anginosus group
30
Which bacterias are associated with Pericoronitis?
Mixed oral Anaerobes (P Intermedia)
S Anginosus group
31
What is the recommended antibiotic for systemic pericoronitis?
Metronidazole
32
What type of bacteria is associated with localised alveolar osteitis?
Mixed oral flora
33
What is Osteomyelitis of the Jaws predisposed by? (5)
Bisphosphonate therapy
Impaired vascularity of the bone (radiotherapy, Paget’s disease)
Foreign bodies (implants)
Compound fractures
Impaired host defences (diabetes)
34
What types of bacteria are associated with Osteomyelitis of the Jaw (4)?
Anaerobic gram negative rods
Anaerobic streptococci
Streptococcus Anginosus
Staphylococcus Aureus
35
What bacterias are associated with M/BRONJ? (3)
S. Anginosus
Mixed anaerobes
Actinomyces Israelii
36
What two bacterias are associated with Salivary Gland infection?
S. Aureus
Mixed Anaerobes
37
What is the treatment for Salivary Gland infection?
Drainage
Flucloxacillin and Metronidazole
38
What are the four stages of Documentation when administering antibiotics?
1. Document diagnosis
2. Document Ab choice, dose, route and duration
3. Document a review date
4. Document deviation from guidance
39
What does SOI stand for?
Severe Odontogenic Infection
40
What is the definition of Ludwig’s Angina?
Bilateral infection of the submandibular space
41
Which three bacterias are commonly associated with Ludwigs Angina?
Anaerobic gram negative bacilli
Streptococcus Anginosus
Anaerobic Streptococci
42
What is the definition of sepsis?
Life threatening organ dysfunction caused by a dysregulated host response to infection
43
What are the two components of a sepsis diagnosis?
SIRS and suspected/confirmed infection
44
What does SIRS stand for?
Systemic Inflammatory Response Syndrome
45
What are the four features of SIRS?
Temperature <36 or >38
Pulse >90/min
Respiratory rate >20/min
White Cell Count <4 or >12
46
How many people die from sepsis per year in Scotland?
3,500
47
What are the treatment principles of Severe Odontogenic Infections?
Diagnose
Seek advice/help
48
What are the 4 factors to consider in Severe Odontogenic Infection diagnosis?
Patient looks unwell
Family or carer is very concerned
There is ongoing deterioration
Physiology is abnormal for this patient (check HR, Oxygen Saturation and Blood Pressure)
49
What are the eight red flags in Severe Odontogenic Infection diagnosis?
New deterioration in Glasgow Coma Scale/ AVPU
Systolic SP <= 90mmHg (or >=40 below normal)
Heart rate >= 130 per minute
Respiratory rate >= 25 per minute
Needs oxygen to keep SpO2 92% (88% in COPD)
Non-blanching rash or mottled/ashen/cyanotic
Not passed urine in last 18 hours
Recent chemotherapy (within 6 weeks)
50
What are the sepsis six?
Give high flow oxygen
Take blood cultures
Give IV antibiotics
Give a fluid challenge
Measure lactate
Measure urine output
51
What does S stand for in microbiology results?
Susceptible at a standard dose
52
What does I stand for in microbiology results?
Susceptible at increased exposure/dose
53
What does R stand for in microbiology results?
Resistant, even with increased exposure/dose
54
What is the definition of a breakpoint?
A chosen concentration (mg/L) of an antibiotic which defines whether a species of bacteria is susceptible or resistant to the antibiotic
55
What is the definition of clinical resistance?
When infection is highly unlikely to respond even to maximum doses of antibiotics
56
What are the laboratory confounding variables of resistance testing?
Inoculum size
Planktonic phase
PH
Atmosphere
Biofilm
57
What are the clinical confounding variables of resistance testing?
Co-morbidities
Pus collections
Foreign bodies
Site of infection
Biofilm
58
What is exposure a function of?
Mode of administration
Dose, dosing interval, infusion time
Distribution/excretion of the antibiotic
Interactions with bacteria at site of infection
59
What is the aim of antimicrobial stewardship?
To preserve antimicrobial medicines by taking measures to promote their control
60
What are the five strategic objectives of Antimicrobial Stewardship?
Improve awareness and understanding
Strengthen the knowledge through surveillance and research
Reduce the incidence of infection
Optimise the use of antimicrobial medicines
Ensure sustainable investment
61
What is the definition of antimicrobial stewardship?
A coherent set of actions which promote using antimicrobials responsibly
62
What is the role of the Scottish Antimicrobial Prescribing Group (SAPG)?
Coordinates the national antimicrobial stewardship programme in humans
63
What is Penicilin V most active against?
Oral streptococci
Anaerobes
Selected gram negative cocci
64
What is amoxicilllin most active against?
Oral streptococci
Anaerobes
Gram negative cocci
Members of the enterobacteriaceae family
65
What antimicrobials is anginosus streptococci invariably sensitive to?
Penicillin V
Amoxicillin
66
What is the first line antimicrobial for dental infection?
Phenoxymethylpenicillin (penicillin V)
67
What is the recommended dose of penicillin V?
500mg every 6 hours for 5 days
68
What are four factors that cause candidosis?
Poor denture hygiene
Hospitalisation
Immunocompromised
Poor oral hygiene
HIV
69
What are the 3 features of Candida albicans?
Hyphae
Hydrolytic enzymes
Adhesions
70
What are the 3 features of Candida albicans?
Hyphae
Hydrolytic enzymes
Adhesions
71
What type of fungus is candida?
A dimorphic fungus present both as yeast (blastosporic) and filamentous (hyphae)
72
What is the size of a yeast cell in comparison to a bacteria?
Yeast cells are 25-50x bacteria cells
73
What are the risk factors of candidiasis?
Immunocompromised patients
Advanced HIV infection
Central venous catheter
Broad spectrum antibiotics
Colonisation at a sterile site
Trauma patient
Immunosuppressive drugs
Intra-abdominal surgery
Parenteral nutrition
Dialysis
Burn unit victim
Long term corticosteroid use
74
What is the classification of oral candidiosis?
Pseudomembranous- thrush
Erythematous- atrophied (HIV-related), denture related
Hyperplastic- candida leukoplakia
Angular cheilitis
75
What are the three Newton’s type for denture induced stomatitis?
Newtons Type 1: localised inflammation
Newtons Type 2: diffuse inflammation
Newtons Type 3: granular inflammation
76
What are the two main species of candida?
Candida albicans
Candida glabrata
77
What are the 4 features of Candida albicans?
Adhesion and colonisation
Hyphal penetration and invasion
Vascular dissemination
Endothelial colonisation and penetration
78
What do hydrolytic enzymes do?
Catalyse the hydrolysis of a substrate through the addition of water
79
What do phospholipases do?
Lipids that allow host cell penetration
80
What do haemolysins do?
RBCs
Facilitates hyphal invasion
81
What do proteinases do?
Protein
Adhesion to epithelial cells
82
What are five methods of collection for laboratory diagnosis?
Smear
Oral rinse
Swab
Foam pad
Biopsy
83
What are the three types of antifungal?
Echinocandins: active against biofilms
Azoles: ineffective against biofilm
Polyenes: active against biofilms
84
What are three examples of echinocandins?
Caspofungin
Micafungin
Aniduafungin
85
What are three examples of azoles?
Fluconazole
Voriconazole
Pocaconazole
86
What are three examples of polyenes?
Nystatin
Amphoteicin B
Liposomal AmB
87
What antifungals are Candida albicans sensitive against?
Fluconazole and Metaconazole
88
What antifungal is candida glabrata sensitive to?
Nystatin
89
Which microbes are associated with periodontitis?
P. Gingivalis
T. Denticola
T. Forsythia
90
Which microorganisms are associated with gingivitis?
Actinomyces
Prevotella intermedia
Bacteriodes
Fusobacterium nucleatum
91
What are the influences on microflora?
Host factors
Diet
Saliva
Gingival crevicular fluid
Microbial interactions
Gaseous environment
92
What is the preferred clinical specimen for oral biofilm infections?
Swab for wound/lesion taken chair side
Cultured on agar plate for incubation
93
What is the preferred clinical sample for an abscess?
Pus
94
What are the six features of the chain of infection?
Infectious agent
Reservoir
Portal of exit
Portal of entry
Mode of transmission
Susceptible host
95
What microorganisms are associated with endodontic infections?
Bacteriodes
Streptococcus
Fusobacterium nucleatum
Prevotella
Clostridium
Lactobacillus
Porpphyomonas endodontalis
96
What microbe is associated with 4-40% of endodontic infections?
Enterococcus faecal is
97
What are examples of virulence factors?
Endotoxins
Adhesions
Collagenases
Hyalurnates
Immune evasion
98
What are bacterial detection methods associated with microbial culture?
Agar medium
Isolate bacteria
Identify by characterisation of enzyme activities
Sugar fermentation tests
99
What are bacterial detection methods associated with molecular biology?
DNA probes
PCR
100
How can we identify anaerobes?
They have a sensitivity to metronidazole
101
What are the advantages of culture methods?
Yields bacterial isolates for future testing and study
102
What are the disadvantages of culture methods?
Required viable cells
Insensitive
Only a small number analysed at once
Inconclusive results
Labour intensive
103
What are the 3 stages of PCR?
Denature (94-95C)
Annealing (50-56C)
Extension (72)
104
What are the advantages of PCR?
Less time consuming than culturing
Very sensitive
Can directly detect bacterial DNA within clinical samples
Does not require viable cells
Can detect uncultivable species
105
What are the disadvantages of PCR?
May detect dead cells
Detects only pre-selected species
106
What are the disadvantages of PCR?
May detect dead cells
Detects only pre-selected species
107
How does a restriction enzyme analysis work?
Digests whole enzyme with restriction enzymes
108
What are the molecular (genetic) typing methods?
Restriction enzyme analysis
Gene probe typing
Ribotyping
109
How does ribotyping work?
Use E-coli rRNA as a DNA probe following restriction enzyme analysis (REA)
rRNA operon present in multiple copies in bacterial genomes
110
What is the mode of action of azole antifungals?
Indirectly target the ergosterol in the fungi cell wall by interrupting the activity of the enzyme that produces it: 14-alpha demethylase
Fungistatic effect
111
What is an example of a polyene anti fungal?
Nystatin
112
What is the mode of action of polyenes?
Directly targets the ergosterol and causes perforation and leakage of intracellular contents
Fungicidal effect
113
What is an example of an echinocandin?
Micafungin
114
What effect do echinocandins have?
Fungicidal
115
What are the factors of chlorhexidine substantivity?
Adsorption to oral surfaces
Maintainacne of antimicrobial activity
Slow neutralisation of antimicrobial activity
116
What is the treatment for erythematous candidiasis
Thorough cleaning of denture: milton soak
117
What is the treatment for pseudomembranous candidiasis?
Nystatin
Topical MW 4x daily
Chlorhexidine adjunct
118
What is the treatment for hyperplasticity candidiasis?
Systemic antifungals
Fluconazole 50mg or Itraconazole 10-20mg
119
What is the treatment for angular chelitis?
Chlorhexidine and miconazole crea, (50mg 7 days)
120
What type of substance is chlorhexidine?
Bisbiguanide
121
What is the mode of action of chlorhexidine?
Dicationic: 1 cation is dental pellicle, 1 cation is bacterial membrane
122
How does chlorhexidine perform at a low concentration?
Increases cell permeability
123
How does chlorhexidine perform at a high concentration?
Causes cytoplasmic and cell death
124
What is the substantivity of chlorhexidine?
12 hours
125
What does substantivity mean?
Persistence of action
126
What is substantivity dependent on?
Absorption to oral surfaces
Maintenance of antimicrobial activity
Slow neutralisation
127
What are the dosing options for chlorhexidine?
0.2% 10ml 2x day
0.12% 15ml 2x day
128
129
What are the virulence factors of candida?
Adhesions
Hyphae
Hydrolytic enzymes
130
What are the mechanisms of antimicrobial resistance?
Biofilm too thick for penetration
Antimicrobial inactive against non-growing organisms
Antimicrobial broken down and destroyed by enzymes
131
What are the stages of biofilm development?
Adhesion
Colonisation
Accumulation
Complex Community
Dispersal
132
What are the key organisms associated with caries?
Streptococcus mutans
Lactobacillus acidophilus
Actinomyces
133
What are the virulence factors for microorganisms associated with caries?
Binding proteins
Acid tolerance
Adaption
Sugar modifying enzymes
Adhesions
Effluent pumps
134
What are the features of acid tolerance?
Maintains pH
Alters cell membrane
Protection and repair mechanisms
135
What are the side effects of chlorhexidine?
Anaphylaxis
Hypersensitivity
Brown staining
Tongue discolouration
Burning gums
Impairs perio healing
136
What does a biofilm compose of?
Aggregate of micro-organisms whose cells adhere to one another and embed in a surface
The adherent cells become embedded within a self produced matrix of extracellular polymeric substances which allow adherence to a surface
137
What is a niche?
The role a species plays in its environment and how it meets its need for food and shelter
138
What is the role of fimbrillar adhesions?
Virulence factors
Help invade membrane vesicles of host cells by binding to cellular integrins
139
What are lipopolysaccharides?
A distinct cell wall component of gram negative bacteria with the potential structural diversity to mediate specific adherence
140
What is lipotechoic acid?
A cell wall component of gram-positive bacteria involved in specific or non-specific adherence
141
What are protein fimbrae?
Filamentous proteins on the surface of bacterial cells that may act as adhesions for specific adherence
142
What are lectins?
Any proteins that bind to a carbohydrate
143
What are examples of host receptors?
Glycolipid
Integrins
Glycoproteins
Collagen
144
What are factors that contribute to successful colonisation?
Adherence, substrate (energy) and a liable environment
Mucosa surface, pellicle, acid rich police proteins, minerals and lectins
Mechanical washing, bacteriocidal enzymes, buffering and secretor IgA
Adhesions, LTA, protease, virulence factors
145
What bacteria is associated with NUG/NUP?
Anaerobic fusospirochetal bacteria
146
When are antibiotics not indicated?
When there is no infection associated with systemic signs
147
What systemic signs provide clear evidence of spreading infection?
Trismus
Lymphadenopathy
Difficulty swallowing
Pyrexia
Tachycardia
148
What is a risk associated with spreading infections in the canine space?
Potential to cause intracranial bacterial infections
149
What signs associated with referral indicate referral to A&E?
Signs of septicaemia such as grossly elevated temperature (39.5C, lethargy, tachycardia)
Spreading cellulitis
Swelling that may compromise the airway or cause difficulty in swallowing or closure of the eye
Dehydration
Significant trismus associated with a dental infection
Failure to respond to previous treatment
An uncooperative patient
150
What is the virulence factor of pseudomonas aeruginosa?
Capsule production
151
What are endogenous sources of pseudomonas aeruginosa?
Oral flora
Hands
152
What are the exogenous sources of pseudomonas aeruginosa?
Water (Dental unit water lines)
Suction system
Aerosol turbines/ultrasonics
Hands
Inadequate decontamination
153
What patients are susceptible to pseudomonas aeruginosa?
Cystic fibrosis
Post op eye infections
Septicaemia in neutropenic
Ecthyma gangrenosa
Burn/graft infections
Hospital acquired pneumonia
Catheter assosciated urine infections
154
How can you break the reservoir chain of infection in regard to pseudomonas aeruginosa?
Avoid damp/wet conditions
Use fresh detergent/disinfectant solutions
Frequently change ultrasonic bath/denture disinfectant
Steriliser reservoir- puridied water and change frequently
155
How can you break the portal of exit chain of infection in regard to pseudomonas aeruginosa?
Use sterile single use solutions where possible
156
How can you break the mode of transmission chain of infection in regard to pseudomonas aeruginosa?
Hand hygiene
Use type b steriliser
157
How can you break the portal of entry chain of infection in regard to pseudomonas aeruginosa?
Aeseptic technique
158
What cells does HIV attack?
CD4+ T cells- allows virus to enter and infect cells
159
What is low CD4+ associated with?
AIDs
160
What does Koch's postulate signify?
Causal relationship between a microorganism and disease
161
What are the four factors of Koch's postulate?
1. Micro-organism present in all cases of the disease
2. Micro-organism must be cultured from a diseased individual
3. Inoculation of a healthy individual with the micro-organism must cause disease
4. The same causative agent can be isolated from the diseased inoculated individual
162
What are the two types of Pattern Recognition Receptors?
Pattern Associated Molecular Patterns (PAMPs)
Damage Associated Molecular Patterns (DAMPs)
163
What are PAMPs?
Conserved exogenous (non-self) factors expressed by pathogens
164
What are examples of PAMPs?
Nucleic Acids
Lipopolysaccharides (LPS)
Peptidoglycan
165
What are DAMPs?
Endogenous (host) factors released following cell damage
166
What are examples of DAMPs?
Heat shock proteins
Nucleic acids
167
What is the overall result of PAMPs and DAMPs?
Activation of inflammatory signalling pathways
168
What is the role of TNF-alpha in sepsis?
TNF-alpha drives sepsis
169
Why does TNF-alpha drive sepsis?
Causes systemic vasodilation
Increases vascular permeability
Decreases blood pressure
Causes systemic blood clotting of microvasculature
170
How is the complement system activated?
PRR recognition of PAMPs and DAMPs
C3a and C5a (peptides)
Immunopathogenesis
171
What are the stages of pathogenicity?
Enter
Attach
Colonise
Evade host immunity
Produce harmful proteins
Disseminate
Release from host
172
What is the microbiome?
All of the micro-organisms in a particular ecosystem
173
What is the human microbiome?
All of the micro-organisms living in the body
174
Where is resident flora from?
Delivery; (vaginal>c section)
Feeding (breast>bottle)
175
What are the effects of host microbiome symbiosis?
Resistance to pathogen colonisation
Cardiovascular resistance
176
What are the benefits of a normal flora?
Vitamin synthesis and excretion
Prevention of pathogen colonisation
Anatagonise other bacteria
Stimulate tissue development
Stimulate production of cross-reactive proteins
177
When does microbial biomass increase?
As alkalinity increases
178
What are the barriers for microbes in the gastointestinal tract?
Low pH
Saliva and bile
Immune system
179
What are the effects of antibiotics on the gut microbiome?
Increased infection susceptibility
Compromised immune homeostasis
Dysregulated metabolism
Accumulation of antibiotic resistances
180
Why do antibiotics cause increased infection susceptibility in the gut microbiome?
Loss of potential competition
Lower antibacterial and IgG exposure
Reduced neutrophil activity
181
Why do antibiotics cause compromised immune homeostasis in the gut microbiome?
Disruption of Treg/Th balance
Elevated inflammatory tone
182
Why do antibiotics cause dysregulated metabolism in the gut microbiome?
Elevated inflammatory tone
Altered insulin sensitivity
Altered metabolism of SCFA and bile acids
183
Why do antibiotics cause accumulation of antibiotic resistances in the gut microbiome?
Establishment of resident bacteria
Transfer of resistant genes to pathogens
184
What is oral dysbiosis driven by?
Major ecological pressure
Increase in GCF
Increase in inflammation
Increased temp/pH
Diet/decreased pH
185
What are the 9 factors associated with oral dysbiosis?
Disease
Diet
Smoking
Alcohol
Oral Hygiene
Antibiotics/Antimicrobials
Act of Salivary Proteins
Salivary Flow
Innate/Adaptive Immune Factors
186
What is 16s RNA?
Biomarker for determining bugs in the mouth
