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Principles SOH > Microbiology > Flashcards

Microbiology Flashcards

(97 cards)

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1
Q

Prion Proteins

A

Smallest infective agents
No DNA/RNA
Mad cow disease
Can’t be sterilised - surgical instruments must be destroyed

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2
Q

Viruses

A

Contain DNA/RNA

Protein coat +/- lipid envelope

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3
Q

Bacteria

A

DNA+RNA
Cell membrane, cell wall
Coccus, bacillus, spirochates

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4
Q

Eukaryote

A

No cell wall

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5
Q

Gram +ve (cell wall)

A

Purple

Many layers of peptidoglycan which holds on to the purple gram stain colour

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6
Q

Gram -ve (cell wall)

A

Pink

Thin layer of peptidoglycan which doesn’t hold on to the gram stain as much so shows up as a pink stain

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7
Q

Lipopolysaccharide

A

Gram -ve

Potent endotoxin

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8
Q

How do bacteria replicate?

A

Binary fission

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9
Q

Bacterial growth curve

A

Lag
Log
Stationary
Decline

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10
Q

“facultative”

A

Can grow with or without oxygen

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11
Q

“obligate”

A

Aerobe - requires O2

Anaerobe - Killed by O2

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12
Q

Exotoxin

A

Mainly gram +ve

Produced inside the cell then EXported from the cell

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13
Q

Endotoxin

A

Mainly gram -ve

Part of the gram -ve cell wall

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14
Q

Spores

A

Inactive forms of bacteria that can survive adverse conditions for many years but can’t replicate
(eg - C. diff)

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15
Q

How do yeasts replicate?

A

Budding

eg: candida

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16
Q

Diagnostic investigations for bacteria

A 
Microscopy
Culture
PCR
Antigen detection
Antibody detection IgM (serology)
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17
Q

Cocci

A

Mainly gram +ve (purple)
Round
Can be in clusters or chains

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18
Q

Cocci chains

A

eg: streptococcus, enterococcus
gram +ve cocci in chains
Differentiate by: Haemolysis test

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19
Q

Cocci clusters

A

eg: staphylococcus
gram +ve cocci in clusters
Bunch of grapes
Differentiate by: Coagulase test

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20
Q

Bacilli

A

Rod shaped

Can be large or small

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21
Q

Spirochates

A

Spiral shaped

Does not stain with gram stain

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22
Q

a-haemolysis

A

Partial haemolysis
Denatured haemoglobin causes green discolouration
eg: strep pneumonia, strep viridans

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23
Q

b-haemolysis

A

Complete haemolysis
Produce exotoxins that lyse red cells in the agar plate
Around the colony there will be a clear zone
eg: group A strep, group B strep

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24
Q

y-haemolysis

A

No haemolysis
Colony has not changed the agar plate at all
eg: enterococci

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25
Group A strep "strep pyogenes"
Most pathogenic strep | Commonly causes tonsilitis
26
Coagulase +ve
Staph aureus
27
Coagulase -ve
``` All staph (apart from staph aureus) Common cause of prosthetic joint and prosthetic heart valve infections Don't produce toxins ```
28
Staph aureus
Can produce exotoxins - damage cells Can produce endotoxins - food poisoning Treatment of choice: flucloxacillin
29
Fever (mechanism)
Antigenic material interacts with macrophages Macrophages release cytokines into bloodstream Cytokines travel to hypothalamus PGE is released which increases body thermal set point Body perceives it's cold and shivers to conserve heat Results in fever
30
Sepsis
Small blood cells become 'leaky' and loose fluid Lower blood vol requires heart to work harder to maintain tissue oxygenation (tachycardia) Poor tissue oxygen perfusion shuts of blood supply to organs to make sure there is enough blood supply for brain Blood clotting system activated Increased risk of haemorrhage
31
Sepsis
Small blood cells become 'leaky' and loose fluid Lower blood vol requires heart to work harder to maintain tissue oxygenation (tachycardia) Poor tissue oxygen perfusion shuts of blood supply to organs to make sure there is enough blood supply for brain Blood clotting system activated Increased risk of haemorrhage
32
Antibiotics
Active against bacteria | Not active against viruses
33
Antivirals
Active against viruses | end in -ivir
34
Virus detection investigation
PCR (detects viral nucleic acid)
35
Spread of infection (5 I's)
``` Inhalation - droplet, airborne Ingestion - contact Intercourse - contact Inoculation - contact Mother to Infant - vertical ```
36
Most commonly missed area of hand hygiene
Thumb | Fingertips
37
When to wash hands (5)
1. Before patient contact 2. Before aseptic task 3. After body fluid exposure risk 4. After patient contact 5. After contact with patient surroundings
38
PPE order
Apron Gloves Gloves Apron
39
Black bag
Domestic waste
40
Orange bag
Clinical waste
41
Orange bag
Clinical waste
42
Bacteriostatic
Inhibits the growth of bacteria
43
Bacteriocidal
Kills bacteria
44
Oral administration
Peak serum levels 1 hour after administration
45
IV administration
Peak serum levels 15 mins after administration
46
Cell wall synthesis
Targeted by b-lactam ring (penecillins, cephlasporins) and glycopeptide antibiotics
47
Beta-lactam antibiotics | and examples
Broad spectrum Consists of all antibiotic agents that contain a beta-lactam ring in their structures Inhibit cell wall synthesis eg: penecillins, carbapenems, cephlasporins Advantages: safe, variety Disadvantages: resistance, allergies, rapidly excreted
48
Penecillins - overview
``` Act on bacterial cell wall Beta-lactam antibiotic Safe in pregnancy Excreted rapidly via kidney Bacteriocidal ```
49
Penecillins - Flucloxacillin
Narrow spectrum | Treatment of choice for staph aureus
50
Penecillins - amoxicillin
Broad spectrum | Challenged by b-lactamases which destroy the beta lactic ring and eventually destroy amoxicillin
51
Penecillins - co-amoxiclav
Broad spectrum b-lactamase inhibitor, thus it is better than amoxicillin Combination of amoxicillin + clavulanic acid
52
Penecillins - temocillin
Narrow spectrum | Treatment of choice for coliforms
53
IV form of penicillin
Benzylpenicillin (aka penicillin G)
54
Antibiotics that act on the bacterial cell wall
Targeted by b-lactam ring Penecillins Cephlasporins Glycopeptides
55
IM form of penicillin
Benzathine penicillin
56
Penecillins - overview
``` All end in "-cillin" Inhibit cell wall synthesis by blocking peptidoglycan formation Beta-lactam antibiotic Safe in pregnancy Excreted rapidly via kidney Bacteriocidal ```
57
Glycopeptides - overview
``` Inhibit cell wall synthesis by inhibiting peptidoglycan synthesis NOT a beta-lactam antibiotic Bactericidal Only works on gram +ve bacteria Excreted via kidneys and urine ```
58
Glycopeptides - vancomycin
Administered IV | Used if MRSA is suspected
59
Antibiotics which inhibit protein synthesis - e.g.
Attach to bacterial ribosomes Mainly bacteriostatic - Usually protein synthesis resumes when antibiotic is removed eg: macrolides tetracyclines Some can be bactericidal eg: aminoglycosides
60
Macrolides
``` Eg: clarithromycin, azithromycin, erythromycin Inhibit protein synthesis Bacteriostatic Erythromycin - safe in pregnancy Excreted via liver ```
61
Tetracyclines
``` Eg: Clindamycin, doxycycline Inhibit protein synthesis Bacteriostatic Broad spectrum Resistance is increasing ```
62
Aminoglycosides
``` Eg: Gentamicin Inhibit protein synthesis Bactericidal Mainly active against gram -ve aerobic organisms (coliforms) Excreted in urine ```
63
Antibiotics which inhibit nucleic acid synthesis - e.g.
Metronidazole Quinolones Fluoroquinolones Trimethoprium
64
Cephlasporins
``` All start in "ceph" or "cef" Act on bacterial cell wall to block peptidoglycan formation Beta-lactam antibiotic Bacteriocidal Broad spectrum Safe in pregnancy Excreted via urine and kidneys ```
65
Quinolones
Eg: ciprafloxicin Inhibit nucleic acid synthesis Bacteriocidal
66
Fluoroquinolones
Inhibit nucleic acid synthesis Bacteriocidal Broad spectrum Excreted via urine
67
Trimethoprium
Inhibit nucleic aid synthesis Broad spectrum Excreted via urine
68
4 C's
Ciprofloxacin - quinolone Cephlasporins - Co-amoxiclav - penecillin Clindamycin - tetracycline
69
Tetracyclines
``` Eg: Clindamycin, doxycycline Inhibit protein synthesis Bacteriostatic Broad spectrum Resistance is increasing ```
70
Aminoglycosides
``` Eg: Gentamicin (IV) Inhibit protein synthesis Bactericidal Mainly active against gram -ve aerobic organisms (coliforms) Excreted in urine ```
71
Combination of antibiotics in TB
To prevent development of resistance
72
Metronidazole
Inhibit nucleic acid synthesis due to strand breaking of DNA Administered oral/IV Used for anaerobes (clostridium, bacteroides) Avoid alcohol
73
Is it safe to combine bacteriocidal and bacteriostatic antibiotics?
NO
74
Fluoroquinolones
Inhibit nucleic acid synthesis Bacteriocidal Broad spectrum Excreted via urine
75
B-lactamases
Act on and destroy antibiotics with a beta lactam ring
76
4 C's
Ciprofloxacin - quinolone Cephlasporins - Co-amoxiclav - penecillin Clindamycin - tetracycline
77
Resistance to antibiotics
Giving unnecessary antibiotics Giving sub-therapeutic doses Genetic mutation - due to fast replication which can cause misreading of DNA
78
Name the most common antibiotic which is given for anaerobe infection?
Metronidazole
79
Name 4 antibiotics which work on anaerobes
Metronidazole Clindamycin Co-amoxiclav Carbapenems
80
Pseudomonas is a strict aerobe/anaerobe?
Strict aerobe
81
Name an example of a spirochete?
Syphilis
82
Gram +ve diplococci
Strep pneumonia
83
Treatment of choice for strep infection?
Penicillin
84
Enterococcus is treated with penicillin. True or false?
False
85
Where is most gram -ve bacilli found
In the gut and urinary tract
86
E coli
Gram -ve Rod shaped bacilli Lactose fermenter
87
Gram -ve intracellular diplococci
Neisseria species
88
Which drug is used for gram -ve organisms if gentamicin is contra-indicated?
Astreolam
89
What does vancomycin treat?
MRSA | Clostridium (c diff)
90
What happens to the agar plate if a bug is resistant to an antibiotic?
There will be growth right up to the disc, the antibiotic doesn't stop the organism from growing
91
What happens to the agar plate if a bug is sensitive to an antibiotic?
There will be a clear area (the drug will stop the bug from getting into that zone)
92
What causes C. diff infection?
Use of broad spectrum antibiotics
93
What is more beneficial: high dose antibiotic therapy for shorter duration? OR low dose antibiotic therapy for longer duration?
High dose for shorter duration
94
Where are gram positive organisms usually found in the body?
Skin and mucous membranes - pneumonia - cellulitis - osteomyelitis - wound infection - line infection
95
Where are gram negative organisms usually found in the body?
GI tract - UTI - peritonitis - biliary infection - pancreatitis
96
Where are anaerobes usually found in the body?
Mouth, teeth, throat, sinuses, lower bowel - abscesses - dental infections - peritonitis - appendicitis
97
Carbepenems
Active against ESBL producers Eg meropenem Reserve antibiotics

Principles SOH (5 decks)

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