Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

LF131 > Antibiotics + superbugs > Flashcards

Antibiotics + superbugs Flashcards

(63 cards)

Start Studying
1
Q

EPS

A

Extracellular matrix made of polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Biofilm structure

A

Microbial cells + EPS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Medical device biofilm structure

A

Single coccoid organism + EPS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Biofilm formation

A
  1. Planktonic cells bind surface
  2. Differentiation
  3. Matrix production
  4. Growth + aggregation
  5. Spore formation + dispersion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Bacteriostatic antibiotics

A

Reversely inhibit bacteria growth
Reply on humeral immunity for eradication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Bactericidal antibiotics

A

Actively kill susceptible bacteria
Serious infections - immune system response weak

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Bactericidal infection examples

A

Endocarditis
Meningitis
Osteomyelitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

PG structure + enzyme

A

GlcNAc + MurNAc alternating residues
Catalysed by transpeptidase + penicillin binding proteins (PBPs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cell wall inhibitors - B lactams

A

B lactic group binds active site of PBP inhibiting cross linking
E.g - penicillins, carbapenems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cell wall inhibitors - glycopeptides

A

E.g - vancomycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Topoisomerase II structure

A

2α2β
α - for negative supercoiling
β - for nicking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

N.A synthesis inhibitors - quinolones

A

Bind α subunit of DNA gyrase enzyme complex
No religation -> dsDNA breaks
Bactericidal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Protein synthesis inhibitors (30s) - aminoglycosides

A

Cause mRNA misreading -> protein misfolding
Bactericidal (more in gram - due to OM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Protein synthesis inhibitors (30s) - tetracyclines

A

Block A site entry on ribosome -> stops protein synthesis
Bacteriostatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Protein synthesis inhibitors (50s) - macrolides

A

Block exit channel -> inhibition of protein elongation
Bacteriostatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Protein synthesis inhibitors (50s) - amphenicols

A

Inhibit peptide bond formation
Bacteriostatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Folate synthesis

A

Produces folic acid
Used in nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Folate synthesis inhibitors - sulfonamides

A

Inhibit dihydropteroate synthase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Folate synthesis inhibitors - trimethoprims

A

Inhibit dihydrofolic acid reductase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Community acquired resistance

A

Outside hospital/healthcare setting
Due to overuse/misuse of antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Intrinsic resistance

A

Existing resistance in natural features of bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Acquired resistance

A

Resistance gained via genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Non-specific resistance

A

Broad range
Due to changes in bacterial physiology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Non-specific resistance examples

A

Porins
Efflux pumps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Specific resistance
Targeted against specific antibiotic Due to mutations/acquisition of genes that encode enzymes
26
B lactam resistance mechanisms
1. PBP mutation decreasing affinity for penicillins 2. Down regulation of porins 3. Up regulation of efflux pumps 4. Extended-Spectrum B-lactamase breaking down antibiotic
27
Quinolone resistance mechanisms
1. Gyrase mutations 2. Plasmid encoded Qtr proteins decrease topoisomerase-DNA binding 3. Plasmid encoded acetylation of ciprofloxacin 4. Plasmid encoded efflux pumps
28
Aminoglycoside resistance
1. Modification by acetyltransferase 2. 16 rRNA methylation preventing antibiotic binding
29
Gram staining
PG detection Quick but poor species resolution
30
Biotyping
Based on growth + metabolism on diff substances East but affected by variations in gene expression + mutations
31
Antibiotyping
Based on antibiotic resistance + susceptibility of diff isolates Easy + early detection of outbreak due to resistance Variations in gene expression + mutations alter resistance rapidity
32
Phage typing
Based on resistance + susceptibility to bacteriophages Reproducible + east Relies on presence of receptors + maintenance of biologically active phages
33
Serotyping
Based on antibody binding to antigens Somatic (O) + flagellar (H) antigens for salmonella differentiation Technical + anti-body cross reactivity
34
RAPD
Random amplification of polymorphic DNA
35
PFGE
Pulsed field gel electrophoresis
36
AFLP
Amplified fragment length polymorphism
37
MLST
Multilocus sequence typing
38
Ribotyping
DNA restriction fragment finger typing of ribosomal subunit genes
39
Gram - superbug features
Pseudomonas aeruginosa Gram negative Not all strains superbugs Opportunistic - targets immunocompromised Pulmonary, urinary, burn and blood infection
40
P.aeruginosa reservoirs
Water Paws + hair of domesticated animals Contaminated oil spills - farms
41
P.aeruginosa biotyping
Cannot ferment sugars (lactose) - lactose- Produces cytochrome c oxidase + does aerobic respiration oxidase+
42
RLFP
Detect + identify variation in homologous DNA sequences Use of RE
43
PFGE technique
Alternating voltage in 3 directions Pulse times are equal so net forward movement
44
PFGE advantages
Good for analysing recent evolutions - outbreaks Discrimination between straits
45
PFGE disadvantages
Technical Subjective results
46
P.aeruginosa DNA cleavage
By Spel R.E Minimal nutrition requirements Wide growth temp (2-42) Inhibited by chlorine levels (2-3ppm)
47
P.aeruginosa + carbapenems
1. Down regulate porins 2. Up regulate efflux pumps 3. Acquisition of carbapenamases - break down antibiotic
48
Modified hodge test
Detect carbapenamases If present then other sensitive bacteria can grow in zone of inhibition - clover shape
49
P.aeruginosa + quinolones (ciprofloxacin)
1. Mutations in GyrA decreasing quinolone-enzyme interactions 2. Plasmid encoded efflux pumps
50
Gram + superbug features
Staphylococcus aureus Most pathogenic
51
S.aureus biotyping - differentiation to streptococcus
Catalase production -> H2O2 breakdown -> H20 bubbles (catalase +)
52
S.aureus biotyping
Coagulase production which converts fibrinogen -> fibrin -> agglutination (coagulase +)
53
MLST technique
1. Amplify 400-500pb fragments in 7 housekeeping genes 2. Sequence fragments using primers 3. Assign allele numbers 4. Combine to make allelic profile 5. Compare to central database using dendrogram to identify strain
54
Nosocomial (HA) acquired infection
In hospital/healthcare setting
55
S.aureus reservoirs
Colonisation of nares (upper respiratory tract) increases risk Infecting strains match the ones of the nares before symptoms begin
56
MRSA epidemiology
Shift from HA-MRSA to CA-MRSA
57
CA-MRSA risk factors
Skin to skin contact Fomites HIV, tattooed
58
S.aureus + penicillin resistance
1. Acquisition of B lactamases
59
Methicillin structure
Modified penicillin Acyl group resists B lactamases
60
S.aureus + methicillin low level resistance
B lactamase hyper production
61
S.aureus + methicillin high level resistance
PBP2a encoded by mecA gene (low affinity for methicillin) Intergrated into chromosome in mobile element (SCCmec) S.sciuri likely donor Can take over PG synthesis
62
Vancomycin mechanism
Glycopeptide antibiotic Binds D-ala motif blocking PBP
63
VRSA
Mutated a.a in side chains of PG preventing vancomycin binding

LF131 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions