Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

The Public 20400 > Streptococci > Flashcards

Streptococci Flashcards

1
Q

What is the etymology of streptococcus pyogenes

A

Etymology:Gr. n.puon(Latin transliterationpyum), discharge from a sore, pus; Gr. suff.-genes(from Gr. v.gennaô), producing; N.L. masc. adj.pyogenes, pus-producing.

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

Detail the microbiology of streptococcus pyogenes

gram, shape, aerobe, movement?

A
  • Gram positive cocci in chains
  • Facultative anaerobe - grows in the presence and absence of oxgyen
  • Group A streptococcus GAS in clincical settings (Lancefield grouping)
  • Non-motile (doesn’t have flagella)
  • may rarely be found in the upper respiratory tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Is it a commensal or Pathogen?

A

Rarely isolated from healthy skin. Can colonise upper respiratory tract of humans

Invasive infections are associated with >25% mortality

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

What are the organisms virulence factors

A

Bacterial capsule (in invasive infections) to evade the immune systems

Exotoxin production - damages host cell structures

Immune evasion and dissemination

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

Which infections do GAS cause

A 
Sore Throat (Bacterial pharyngitis) 
Impetigo (sometimes)
Scarlet fever 
Cellulitis 
Necrotising fasciitis (Rare) Revisit in year 4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is cellulitis

A

An acute infection of the skin involving the dermis and subcutaneous tissues

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

How does a patient become infected with cellulitis

A 
Causative agent enters via a break in skin
Cut, graze
Burn
Bite (e.g.) spider, dog, horse fly
Skin ulcer
Skin condition – e.g., eczema, psoriasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the signs and symptoms of cellulitis

A

Skin becomes red, hot, swollen, tender, painful
Commonly affects legs
Blisters (sometimes)

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

What are the risk factors for cellulitis

A

Obesity
Poorly managed diabetes - blood flow compilcations leading to a less efective immune response
IV drug use - if the needles are unhygenic
Previous cellulitis history
Swimming! Bodies of water may harbour bacteria
Smoking

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

Where are the areas of the body which are endogenous carriers of Gp A streptococci

A

Interdigital toe spaces
Vagina
Anus

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

What are the complictions of poorly managed cellulitis

A

Spread of infection to other body sites (blood, muscle, bone); Lymphoedema; Recurrent cellulitis

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

What are the differential diagnoses (things which may present similarly to cellulitis but arent)

A

Eczema (In particular varicose eczema) Eczema doesnt have a changing border
Lymphoedema - isnt hot to the touch
Allergic reaction - isn’t so localised

All of the above conditions will have a history

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

How do we manage mild cellulitis with no systemic toxicity (in the community)

A 
Pain management (paracetamol, ibuprofen)
Adequate fluid intake

High dose oral antibiotic (7-14d)
Phenoxymethylpenicillin (clarithromycin/clindamycin)

Refer if facial cellulitis, severe (rapidly spreading, fever, change in mental state), patient is very young (< 1 yo)
Hospital admission – IV Benzylpenicillin (Vancomycin)

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

What is the pharmacists role in mild cellulitis management

A
  • Pick up on any danger symptoms and advise patient accordingly
  • OTC pain relief if appropriate e.g. Paracetamol / Ibuprofen (this shouldn’t delay antibiotic prescribing)
  • If leg affected keep it raised

Public health

  • Treating skin wounds
  • Hand hygiene
  • Keep skin moisturised (emollients in eczema, psoriasis) and therefore manage risk factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is GAS

A

Group A Streptococcus (pyogenes)

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

Give some of the aetiology of strep throat

transmission, age, time of year, medical conditions, medication

A 
-Transmission
Droplets in the air /direct contamination of wound
-Age
Young (5-15 years)
-Time of year (Spring, Autumn)
-Medical conditions (immunosuppression)
HIV/AIDS
Leukaemia
Asplenia
Aplastic anaemia
-Medication (immunosuppressive)
Chemotherapy, Carbimazole, DMARDs etc
17
Q

What are the signs (what a practitioner can see) and symptoms (what the patient can feel) of strep throat

A
  • Swollen tonsils
  • Painful, tender
  • Discomfort when swallowing
18
Q

What other things can present like step throat

A 
Glandular fever
Viral infection (presents witha fever)

Cancer
Persistent sore throat (typically in over 45s and history of smoking)

Quinsy (peritonsillar abscess)
Painful collection of pus (usually one-sided)

Epiglottitis
Inflammation of epiglottis - typically seen in children 2-6 (rare now in britain due to vaccination) Is a medical emergency

19
Q

How do we manage strep throat

A

Often no treatment required

OTC- analgesics / anaesthetic & antibacterial lozenges /sprays/ mouthwashes

Antibiotics (Fever and pain)
Phenoxymethylpenicillin; qds, 5-10d OR Clarithromycin; bds, 5d)

Systemically very unwell - difficulty breathing, medical emergency -> Hospitalisation

20
Q

What is the pharmacists role around strep throat

A

Check Patient Medical Record for any ADRs (around 1 in 10 people have a penicillin allergy)
Eliminate any danger symptoms
Recommend appropriate OTC products to manage symptoms
Non-medicated lozenges and local anaesthetic mouthspray not supported by evidence

Public health
Maintain good hygiene
Wash hands regularly
Cover your mouth when coughing (with a tissue)

21
Q

What are the signs and symptoms of scarlet fever

A

Initial flu-like symptoms

- High temperature
- Sore throat 
- Swollen neck glands

Eventual rash (sandpaper-like) development

May develop strawberry tongue - often has a white coating

22
Q

What is the causative agent of scarlet fever

A

Streptococcus A - exotoxin mediated. It can evolve from strep throat or a wound

23
Q

Who does scarlet fever usually affect

A

Children 10 and under (not newborns though due to maternal antibodies)

24
Q

How do we manage scarlet fever

A 
-Suspected but person otherwise well
Phenoxymethyl penicillin (PenV), qds, 10 days
Dose dependant on age
Azithromycin if pen allergic 
once a day, 5 days
-Manage pain and itching
- this can go on to cause cellulitis

Hospital admission if:

  • Pre-existing valvular heart disease
  • Immunocompromised
  • Suspect severe complication (e.g.) toxic shock syndrome
25
Q

What is the pharmacists role

A

Public health
Highly infectious, easily spread
-Wash hands
Trap aerosols in tissues – bin it kill it

Symptom management
Pain, fever management (paracetamol, ibuprofen)
Itching (calamine lotion, antihistamines)

Scarlet fever is a notifiable disease - PHE needs to know

26
Q

What is the microbiology of Streptococcus pneumoniae

gram, motility, capsule type, where it lives

A
  • Gram positive coccus (its a diplococcus)
  • > 90 capsular types reported
  • Non-infectious forms typically non-capsulated
  • Non motile (no flagella)
  • Normal inhabitant of URT (both transiently and chronically)
  • Nasal cavity
  • Pharynx
  • Nasopharynx
  • 20-50% children
  • 5-20% adults
27
Q

How long can Streptococcus pneumoniae last in the environment

A

Up to 4 weeks and can be carried from person to person

28
Q

What is community acquired pneumonia

A
  • A pneumonia acquired outside of the hospital setting or onset within 48h of hospital admission
  • Frequently caused by S. pneumoniae (other causes leigonaires disease, micoplasma bacteria)
  • 5th leading cause of mortality (Europe)
29
Q

What ar the risk factors for CAP

A

Smoking - paralysed scilia
Contact with children
Poor oral hygiene
Age (>65y) - innate defences are less effective
Alcohol abuse - damages innate defence mechanisms

30
Q

How do people become carriers for strep. pneumo.

A

Pneumococci can be (transiently) carried in the nasopharynx
Typically acquire via asymptomatic nasal colonisation. The infection process follows this path:

Negatively charged capsule expression reduces entrapment in the innate defence mechanism mucous 
Intimate association to host cells following down regulation of capsule
Neutrophil influx (1-3 d post colonisation). This often initiates clearance of the bacterium
However, if clearance doesnt fully occur carrier state persists (d14)
31
Q

How do patients move from carrier state to becoming infected with strep pmeuno.

A

In some cases, there is a switch from carriage to invasive infection. More common in over 65s. The bacteria move from the nasopharynx to the lower respiratory tract

Initially mild irritation of upper airway

Short incubation period (1-3d)

Fever, malaise

Dyspnoea, shaking chills

Productive cough (purulent discharge)

May progress to acute respiratory failure or death (if untreated)

32
Q

Which cells are involved in the initial response to strep. pneum. infection

A

Macrophages - initial response
If this fails there is neutrophil recruitment to the area. This leads to inflammation in the LRT lungs. This can be removed by a healthy individuals immune system

33
Q

Which virulence factors does SP have to enable it to infect the host

A
  1. Polysaccharide Capsule
    - Sp virulence is associated with capsule thickness
    - it works through a charge interference, it has a very similar charge to the phagocytic cells hence pushes them away
    - High surface charge interferes with phagocyte interactions
    - Reduces complement deposition at bacterial surface
  2. Pneumolysin
    - Pore forming toxin produced by lysed bacterial cells
    - Innate defence inhibition (can damage scillia)
    - Induction of cytokine release adding to the inflammatory resopnse
34
Q

How do we manage SP and designate the severity of the disease

A

Severity assessment in adults with symptoms suggestive of CAP is determine through (i) clinical judgement and (ii) CRB-65 scoring

1 point given for each of following prognostic features

- Confusion 
- Respiratory rate (≥30 breaths/min)
- Blood pressure (diastolic ≤60 mmHg or systolic <90 mmHg).
- Age ≥65y

Scores (risk of death)
0 = Low (< 1% risk of mortality)
1 or 2 = Intermediate (1-10% risk of mortality)
3 or 4 = High (> 10% risk of mortality) need urgent hospital admision

35
Q

What management do we use for patients with a low CRB-65 score

A

LOW (score = 0) Consider community management
Amoxicillin (500mg, tds, 5d, oral)
Alternative options are doxycycline (atypicals?) or clarithromycin (pen allergy)

36
Q

What management do we use for patients with a moderate CRB-65 score

A

MODERATE (score = 1 or 2)
Consider hospital assessment
Amoxicillin WITH (if atypical suspected) clarithromycin or erythromycin (in pregnancy)
Doxycycline and clarithromycin if pen allergy
Local antibiotic policy may also apply

37
Q

What management do we use for patients with a severe CRB-65 score

A

SEVERE (score = 3 or 4) Urgent hospital admission
Hospital admission, IV antibiotics common
NICE (Sep 2019) = Co-amoxiclav WITH clarithromycin OR erythromycin (if pregnant)
Local antibiotic policy may also apply

38
Q

What can pharmacists do to limit the spread od CAP

A

Smoking cessation information
Patient education on pneumonia - leaflets, nhs website
Self management strategies – rest, analgesia, adequate fluid intake.
Vaccination information
OTC cough medication not recommended - they dont work in this setting

39
Q

What is the difference between a bacterial developed pneumonia and a covid aquired pneumonia

A

Prior exposure to covid case

A productive cough is associated with bacterial infections (covid is dry)

The Public 20400 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions