(PM3A) Bacterial Infections Flashcards
1
Q
Describe the structure of gram positive bacteria.
A
(1) Simple structure
(2) 50% Peptidoglycan
(3) 40-45% acidic polymer
(4) 5-10% proteins & polysaccharides
2
Q
Describe the structure of gram negative bacteria.
A
(1) Complex structure
(2) Periplasmic space
(3) Thin peptidoglycan layer
(4) Outer membrane
(5) Complex polysaccharides
3
Q
Name 2 types of gram positive bacteria. Describe their shape. Can these also be gram negative?
A
(1) Cocci - spherical
(2) Bacilli - rods
Yes, bacilli and cocci can also be gram negative
4
Q
What are the 2 types of cocci.
A
(1) Staphylococci - clusters
(2) Streptococci - pairs/ chains
5
Q
How many types of cocci are there?
A
Two.
Staphylo and Strepto
6
Q
(1) What are the two types of streptococci?
(2) What are the differences?
A
(1) Hemolytic and non-haemolytic
(2) Hemolytic can break down blood cells
7
Q
What is S. pneumoniae? Is it vaccinated?
A
A hemolytic streptococci (bacteria)
Vaccinated
8
Q
What are the 4 types of bacilli?
A
(1) Spore-forming
(2) Non-spore-forming
(3) Branching
(4) Acid-fast
9
Q
What type of bacteria are aerobic and anaerobic bacteria?
A
Spore-forming bacilli
10
Q
Give an example of a spore-forming anaerobic bacteria.
A
C. tetani
Bacilli
11
Q
What type of bacteria is C. tetani? Is it vaccinated?
A
Anaerobic spore-forming bacilli
Vaccinated.
12
Q
What are the different types of non-spore-forming bacilli? Give an example genus for both.
A
(1) Motile - Listeria
(2) Non-motile - Lactobacilli/ Corynebacteria
13
Q
What is C. diphtheriae? Is it vaccinated?
A
A non-motile non-spore-forming bacilli
Vaccinated
14
Q
Name an example of an acid-fast bacteria. Give an example of one. Is it vaccinated?
A
Mycobacteria
M. tuberculosis
No longer vaccinated.
15
Q
What is M. tuberculosis? Is it vaccinated?
A
A mycobacteria.
No longer vaccinated
16
Q
Describe M. tuberculosis.
A
(1) Mycobacteria
(2) Acid-fast
(3) Bacilli
(4) Gram-positive
17
Q
Describe C. diphtheriae.
A
(1) Non-motile
(2) Non-spore-forming
(3) Bacilli
(4) Gram-positive
18
Q
Describe C. tetani.
A
(1) Anaerobic
(2) Spore-forming
(3) Bacilli
(4) Gram-positive
19
Q
Describe S. pneumoniae.
A
(1) Hemolytic
(2) Streptococci - pairs/ chains
(3) Cocci
(4) Gram-positive
20
Q
Name two types of gram negative bacteria. Can these also be gram positive?
A
(1) Cocci
(2) Bacilli
Yes, bacilli and cocci can also be gram positive.
21
Q
What is N. meningitidis? Is it vaccinated?
A
A bacterium of the Neisseria genus.
Vaccinated
22
Q
What are the 3 types of gram negative bacilli?
A
(1) Coccobacilli
(2) Long-rods
(3) Curved/ spiral rods
23
Q
(1) What are two coccobacilli that are vaccinated against?
(2) Are they gram positive or gram negative?
A
(1) B. pertussis and H. influenzae
(2) Gram negative
24
Q
What are the 3 types of long-rod bacilli?
A
(1) Enterobacteria: (non)lactose-fermenting
(2) Bacteroides
(3) Pseudomonas
25
What are 3 types of curved/ spiral rod bacilli?
(1) Campylobacter
(2) Helicobacter
(3) Vibrio
26
What is the mechanism of action of penicillins?
Inhibition of cell wall synthesis
It is a beta lactam
27
What is the mechanism of action of macrolides?
50S protein synthesis inhibition
28
What is the mechanism of action of tetracyclines?
30S protein synthesis inhibition
29
Name 5 ways that bacteria may have developed antibiotic resistance.
(1) Impermeability to antibiotic
(2) Efflux pumps - to remove antibiotic
(3) Degradation - conversion of antibiotic to inactive form
(4) Change in antibiotic's target structure
(5) Altered metabolism/ use of an alternative pathway
30
When does the UK routine immunisation schedule begin and end (age of patient)?
8 months --> 70 years
31
Name 7 ways to reduce antibiotic resistance.
(1) Surveillance/ guidance
(2) Antimicrobial stewardship
(3) Increasing awareness
(4) Training/ education
(5) Research into diagnosis + treatment
(6) Drug development
(7) International collaboration
32
What are the causes of a lower UTI?
Commonly bacteria
| - Usually E. coli in bladder/ urethra from GIT
33
What are the risk factors for a lower UTI?
(1) Females - urinary system + GIT in close proximity
(2) Sexual activity
(3) Pregnancy
(4) Genetic predisposition
(5) Post-menopausal
(6) Diabetes
34
What are the symptoms of a lower UTI?
(1) Increased urination frequency - polyuria
(2) Burning in urination - dysuria
(3) Cloudy urine
(4) Strong-smelling urine
(5) Lower abdominal discomfort
35
What is the first line treatment for a lower UTI?
For women:
- Nitrofurantoin
- 100 mg M/R
- BD
- 3 day course (increase duration if pregnant)
36
What is the second line treatment for a lower UTI?
Fosfomycin/ pivmecillinam
37
What is the most common cause of an infection in the GIT?
Faecal-oral transmission
38
What is the treatment for MOST GIT infections?
No treatment - normally self-limiting
| Stay hydrated
39
Name a bacteria that can infect the stomach.
H. pylori
40
What organs comprise the small intestine?
(1) Duodenum
(2) Jejunum
(3) Ileum
41
(1) Where does an H. pylori infection often take place?
| (2) What is the treatment for infection with this bacteria?
(1) Stomach
| (2) PPI + Clarithromycin/ metronidazole + amoxicillin for a duration of 7 days
42
(1) What is infective endocarditis?
| (2) What is its rarity?
Bacterial (usually) infection of the heart, often valves
Rare
43
What are the most common causes of infective endocarditis?
(1) Strep
| (2) S. aureus
44
What are the symptoms of infective endocarditis?
(1) Fever/ chills
(2) Heart murmurs
(3) Fatigue
(4) Cough
(5) SOB
(6) Headache
(7) Night sweats
45
What is the treatment for infective endocarditis?
If strep:
- A penicillin + gentamicin
If staph:
- A penicillin + flucloxacillin
46
When is penicillin required for infective endocarditis?
Always
In addition to gentamicin/ flucloxacillin
47
Under what conditions is flucloxacillin required for treatment of infective endocarditis?
(1) Staph infection
| (2) As well as a penicillin
48
Under what conditions is gentamicin required for treatment of infective endocarditis?
(1) Strep infection
| (2) As well as a penicillin
49
How does treatment for serious infective endocarditis differ from normal treatment?
(1) Ampicillin for 2-6 weeks
| (2) Surgery if necessary
50
What is bacterial vaginosis often mistaken for?
Thrush
51
What is the rarity of bacterial vaginosis?
Common
52
What is the cause of bacterial vaginosis?
(1) Overgrowth of bacteria in the vagina
| (2) Anaerobic bacteria
53
What are the symptoms of bacterial vaginosis?
Discharge:
- White/ pale grey discharge
- Milky discharge
- Fishy-smelling
54
What is the treatment for bacterial vaginosis?
- Metronidazole
- Oral
- 400mg
- BD
- 5-7 day treatment
- Can be a 2g single dose of metronidazole gel
55
Is itching/ burning/ irritation usually present in bacterial vaginosis?
No.
56
What are the similarities and differences in symptoms between bacterial vaginosis and thrush (candidiasis)?
(1) Similarities:
- Increased vaginal discharge
- White discharge
(2) Differences:
- BV discharge can be grey
- Discharge in BV is smooth, thrush is curded
- BV smells fishy, thrush no odour
- Thrush itches + burns, BV does not
57
Which skin layer(s) does acne affect?
Epidermis - hair follicle
58
Which skin layer(s) does impetigo affect?
Epidermis
59
Which skin layer(s) does cellulitis affect?
(1) Dermis
| (2) Subcutaneous fat
60
What infections affect the epidermis?
(1) Acne - hair follicle
| (2) Impetigo
61
What infections affect the dermis?
Cellulitis
62
What infections affect the subcutaneous fat?
Cellulitis
63
What causes an impetigo infection?
Infection with S. aureus/ S. pyogenes in breaks in the skin
64
What are the symptoms of impetigo?
(1) Sores - red spots/ blisters
| (2) Swollen glands
65
What is the treatment for impetigo? How does this vary for localised/ systemic?
(1) Good hygiene
(2) Localised area:
- Topical fusidic acid for 5 days
- Topical mupirocin 2% for 5 days if MRSA
(3) Systemic:
- Oral flucloxacillin 250-500mg QDS for 7 days
- Clarithromycin 250-500mg BD for 7 days (if allergic)
66
What is cellulitis?
Inflammation of the skin and subcutaneous tissues (fat)
67
What are the symptoms of cellulitis?
(1) Red
(2) Hot
(3) Swelling/ inflammation
(4) Painful
68
What causes cellulitis?
(1) S. pyogenes - most common
| (2) S. aureus - in damaged skin
69
What is the treatment for mild cellulitis?
- Flucloxacillin (clarithromycin if penicillin allergy)
- 500mg
- QDS
- 7 days
70
What is the treatment for gram negative cellulitis?
Broad-spectrum antibiotic - e.g. amoxicillin
71
What causes bacterial conjunctivitis?
(1) S. aureus
(2) H. influenzae
(3) S. pneumoniae
72
What are the symptoms of bacterial conjunctivitis?
(1) Thick + yellow discharge (mucopurulent)
(2) Gritty feeling in eye
(3) Pink/ red eye
73
What is the first line treatment for bacterial conjunctivitis?
(1) Self-care
| (2) Bathe + Clean
74
What is the second line treatment for bacterial conjunctivitis?
(1) OTC Topical Antibiotics
- Chloramphenicol 0.5% drops
- Chloramphenicol 1% ointment
(2) Self-care
75
What are the two potential treatments for bacterial conjunctivitis? When are they used.
Chloramphenicol 0.5% drops or 1% ointment
As second line treatment
76
What is the self-care advice for bacterial conjunctivitis?
(1) Bathe eyes
(2) Lubricate eyes
(3) Prevent spread
77
What is otitis externa? What is it known as more colloquially?
Infection of the outer ear
Swimmer's ear
78
What are the causes of otitis externa?
Mainly bacterial
- S. aureus
- P. aeruginosa
Can also be fungal
79
What are the symptoms of otitis externa?
(1) Pain
(2) Itchiness
(3) Discharge
(4) Temporary/ slight hearing loss
(5) Feeling of pressure
80
What is the treatment for otitis externa?
(1) Self-care
- Pain relief
- Localised heat
(2) Clotrimazole if fungal
(3) If bacterial:
- Topical acetic acid 2%
- Topical antibiotic - neomycin
- Corticosteroid - betamethasone
81
What is otitis media? What is its rarity?
Infection of the middle region of the ear
Most common cause of ear pain in children
82
What is the cause of otitis media infection?
(1) Usually viral
(2) Can be bacterial:
- S. pneumoniae
- H. influenzae
83
What are the symptoms of otitis media?
(1) Ear ache
(2) Fever
(3) Vomiting
(4) Fatigue
(5) Slight hearing loss
84
What are the similarities and differences between the symptoms of otitis externa and otitis media?
(1) Similiarities:
- Pain/ ear ache
- Slight hearing loss
(2) Differences:
- externa is itchy, with discharge + feeling of pressure
- media gives fatigue, fever + vomiting
85
What is the treatment for otitis media?
(1) Self-care
- Pain relief
(2) If severe
- Antibiotics (amoxicillin)
86
What is the cause of a sore throat?
(1) Usually viral
(2) Can be bacterial
ø Strep throat - caused by airborne droplets
87
What are the symptoms of a sore throat?
(1) Pharyngitis - throat inflammation
| (2) Tonsillitis - tonsil inflammation
88
What is the treatment for a sore throat?
(1) Self-care
ø Salt gargle
ø Increased fluids
ø Painkillers
(2) Phenoxymethylpenicillin - severe bacterial infections
- Covers group A streptococcus (GAS)
89
What is septic arthritis?
Infection of the joints
90
What is the treatment for septic arthritis?
Flucloxacillin for 4-6 weeks
91
What is osteomyelitis?
Infection of the bone marrow
92
What is the treatment for osteomyelitis?
(1) Flucloxacillin for 6 weeks
| (2) Sometimes + fusidic acid/ rifampicin for first 2 weeks
93
What is the role of the pancreas?
Blood glucose regulation
94
What is bacterial meningitis?
Infection of the central nervous system
95
What is the cause of bacterial meningitis? How does this differ for old/ young patients?
(1) Older children/ adults:
- S. pneumoniae
- N. meningitidis
(2) Young children:
ø H. influenzae
96
What are the symptoms of bacterial meningitis?
(1) Headache
(2) Stiff neck
(3) Fever
(4) Non-blanching rash - meningococcal (N. meningitidis)
(5) Photophobia
(6) Altered consciousness
97
What is the treatment for bacterial meningitis?
(1) If meningococcal (N. meningitidis):
- Parenteral benzylpenicillin
(2) In hospital:
ø IV ceftriaxone/ cefotaxime
(3) Can also use corticosteroid - dexamethasone
98
What are the preventative measures for bacterial meningitis?
Vaccination
99
What does the bacterial meningitis vaccination include?
(1) HiB
(2) MenB
(3) MenC
(4) MenACWY
100
What is sepsis? What does it do to the body?
(1) An inflammatory immune response to infection
| (2) Damages tissues and organs
101
What are the molecules that damage the body's tissues and organs in sepsis called?
(1) Endotoxins
| (2) Exotoxins
102
How do the 3 types of endo/ exotoxins damage the body's tissues and organs?
Type 1 - Disrupt host cell (without entry)
Type 2 - Destroy host cell membranes to invade and interrupt host defence
Type 3 - Disrupt host cell defence to allow dissemination of infection
103
What are the underlying infections that can cause sepsis?
(1) Usually bacterial
ø Gram+ (Staph)
ø Gram- (E. coli)
(2) Less commonly fungal/ viral
104
What are the most common infection sites leading to sepsis?
(1) Lungs (50%)
(2) Urinary tract (20-25%)
(3) Abdominal (15-20%)
(4) Skin/ soft tissue (10-15%)
105
What are the symptoms of sepsis?
(1) Fever/ low body temperature
(2) Elevated HR
(3) Elevated RR
(4) Low BP
(5) Confusion
(6) Pale blotchy skin & non-blanching rash
(7) Significantly reduced urination
106
What is the treatment for sepsis?
(1) Antibiotics PRN
(2) IV fluids PRN
(3) Oxygen PRN
107
What is a nosocomial infection?
Healthcare associated infection
| HCAIs
108
What is an HCAI and what is another name for it?
Healthcare associated infection
Nosocomial infection
109
What is Clostridium difficile?
Gram positive, anaerobic, spore-forming rod
110
What is another name for Clostridium difficile?
Clostridioides difficile
111
What is Clostridioides difficile?
Clostridium difficile
Gram positive, anaerobic, spore-forming rod
112
What is a CDI?
Clostridium (clostridioides) difficile infection
113
What is the effect of broad-spectrum antibiotics on CDIs?
Increases the infection
Proportional to the duration of exposure to the antibiotic
114
Which two conditions is a CDI significantly implicated in?
(1) AAD - Antibiotic-associated diarrhoea
| (2) AAC - Antibiotic-associated colitis
115
What is the difference in mortality rate when a CDI is present?
8%
116
What are the common symptoms of a CDI?
What are the rare symptoms of a CDI?
(1) Mild-moderate diarrhoea
(2) Mild-severe abdominal cramping/ pain
(3) Yellow-white plaques on the intestinal mucosa (only if SEVERE)
RARE:
(1) Fulminant life-threatening colitis (severe + sudden)
(2) Low-severe fever
(3) Dehydration
117
(1) What are the different categories for CDI severity?
| (2) How is the severity determined?
(1) MILD:
ø Normal WCC
ø <3 loose stools in a day
ø 5-7 on Bristol Stool Chart
(2) MODERATE:
ø Increased WCC - >15x10^9/ L
ø 3-5 loose stools in a day
(3) SEVERE:
ø Increased WCC - >15x10^9/ L
ø Acutely increased serum creatinine (+>50%)
ø Temperature >38.5ºC
ø Evidence of severe colitis
ø Stools are no longer relevant in determining severity
(4) LIFE-THREATENING:
ø Hypotension
ø Partial-complete ileus (obstruction of the ileum)
ø Toxic megacolon (rapid widening of the colon)
ø CT evidence of severe disease
118
What are common risk factors for CDIs?
(1) Increased age
(2) Proximity to infected patients - e.g. hospital staff
(3) Nasogastric tube
(4) Gastric surgery
(5) PPIs
(6) Increased hospital stay
(7) Underlying disease - e.g. IBS
(8) Chemotherapy
(9) Increased exposure to antibiotics
(10) Courses of multiple antibiotics
119
What antibiotic can cause a CDI?
Any antibiotic
Traditionally: clindamycin
120
Define 'pathogenicity'.
The process of causing a disease
121
Why can antibiotic therapy increase risk of CDI?
Can affect the healthy flora of the colon
122
What is the pathogenicity of C. diff?
(1) Antibiotic therapy affecting healthy colon flora
(2) Toxicogenic stains producing A + B toxins
ø Some strains also produce binary toxin (CDT)
123
What causes diarrhoea in CDIs?
Toxins
124
What causes fluid secretion and intestinal inflammation in CDIs?
Toxin A
125
What does toxin A do in C. diff infections?
(1) Causes fluid secretion
(2) Causes intestinal inflammation
(3) Activates cytokine release
126
What activates cytokine release in CDIs?
Toxin A & Toxin B
127
What is the trend of a CDI when binary toxins (CDT) is present?
Increased severity
128
What are the stages of progression of a CDI?
(1) Uncolonised
(2) Asymptomatic colonisation
(3) Toxin production
(4) CDI
129
How is a CDI diagnosed based on clinical symptoms and risk factors?
(1) Diarrhoea
(2) ABx exposure
(3) History - can lead to recurrent CDI
130
How is a CDI differentially diagnosed?
(1) Cytotoxic assay
(2) Toxigenic culture
(3) ELISA for toxins A + B
(4) PCR for toxin genes
- Presence of the gene does NOT mean presence of the toxin
131
How is a suspected CDI managed?
(1) Cessation of offending antibiotic
(2) Symptomatic treatment
ø Fluid + electrolyte replacement
ø NOT antidiarrhoeals
(3) Specific ABx therapy usually indicated
132
What is the first line therapy for treatment of a mild-moderate CDI?
```
(1)
ø Metronidazole
ø 400 mg
ø TDS
ø Oral
ø 10-14 day duration
```
(2) Switch to 500mg TDS IV if oral FAILS
(3) Switch to VANCOMYCIN if treatment FAILS
133
What is the first line therapy for treatment of a severe CDI?
```
(1)
ø Vancomycin
ø 125-500 mg
ø QDS
ø 10-14 days
```
(2) ORAL vancomycin is ineffective as it is poorly absorbed
134
Which antibiotic is potentially superior to vancomycin for preventing recurrent CDI?
Fidaxomicin
135
What is the rarity of recurrent CDI?
Up to 1/3 cases
136
How does treatment differ for recurrent CDI?
(1) Same treatment as before
| (2) Often switched to oral vancomycin or fidaxomicin
137
What treatment is gaining importance as a possible treatment for recurrent CDI?
Faecal transplantation
138
What treatment can be administered in recurrent CDI, in addition to antibiotic therapy? Give an example.
(1) Monoclonal antibodies
(2) Selective against toxin B
(3) Bezlotoxumab
139
How are CDI controlled in hospitals?
(1) Good infection control - thorough hand washing
(2) Cohorting/ isolation of infected patients
(3) PPE
(4) Increased monitoring
(5) Improved education on ABx use
140
What is antimicrobial stewardship?
(1) Reduction in inappropriate ABx use
(2) Improvement in susceptibility profiles of hospital pathogens
(3) Better selection, dosing, route of administration, and therapy duration of ABx
To REDUCE ABx resistance
141
Why is antimicrobial stewardship important?
Drug resistant pathogens have an impact on care
142
What are the 7 antimicrobial stewardship strategies?
(1) Formulary restriction
(2) Review/ audit + feedback
(3) Education + guidelines
(4) Streamlining/ de-escalation
(5) IV -> Oral
(6) Antibiotic cycling
(7) Supplementary strategies
143
What is the formulary restriction in antimicrobial stewardship? What are the pros and cons?
- Restricted dispensing for certain ABx
- AMS team must be contacted by prescriber
+
ø Direct control of ABx
ø Cost-effective
ø Ensures appropriate therapy
-
ø Loss of autonomy for prescribers
ø Time-consuming
144
What is review/ audit + feedback in antimicrobial stewardship? What are the pros and cons?
- Daily review of ABx appropriateness
- Steward (pharmacist) gives feedback to prescriber
+
ø Maintained prescriber autonomy
ø Individual education
-
ø Compliance is only voluntary
ø Increases workload of pharmacist
ø Reactive, rather than proactive
145
What are education/ guidelines in antimicrobial stewardship? What are the pros and cons?
- Can be issued by NHS or government
- Education of clinicians
+
ø Maintained prescriber autonomy
ø May alter behaviour patterns
-
ø Mostly ineffective by itself
146
What are streamlining/ de-escalation in antimicrobial stewardship? What are the pros and cons?
- Use of results-based therapy
- Use of patient-specific rather than broad-spectrum
+
ø Avoids long-term broad-spectrum ABx
ø Reduces resistance risk
-
ø Increased pharmacist workload
ø Sample-processing time
147
What is the IV to Oral switch in antimicrobial stewardship? What are the pros and cons?
- Use of oral ABx in hospital
- Many oral ABx have good absorption + bioavailability
+
ø Avoids entry site infections
ø Cost savings
-
ø Compliance
148
What is antibiotic cycling in antimicrobial stewardship? What are the pros and cons?
- Avoids resistance to any single antibiotic
- Aims to slow resistance
+
ø May reduce drug resistance by changing selective pressure
-
ø Adherence
ø Effectiveness lacks evidence
149
What are the supplemental strategies in antimicrobial stewardship?
(1) Decrease ABx usage
(2) Mathematical modelling
(3) Combination of the other 6 strategies
150
What are the goals of the UK 20-year vision for antimicrobial resistance?
(1) Half gram-negative healthcare-associated infections
(2) Reduce drug-resistant infections by 20% by 2025
(3) Reduce ABx use by 15% by 2024
