Microbiology and Pharmacology Flashcards by Sophie Baird

What are the main virulence factors and their functions?

adhesin: enables the binding of organism to the host tissue
impedin: enables the organism to avoid host defence
aggressin: damage to host directly

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What are the main features of Staph?

colonises skin and mucous membranes
can cause superficial lesions and systemic issues such as toxic shock which is caused by TSST-1
PVL is in extreme skin infections and leads to sepsis and necrotising fasciitis

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What are the main features of TSST-1?

this is a super antigen which stabilises immune reaction and causes both release of cytokines and toxic menstrual shock

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What are the main features of Strep?

normally in the pharynx
Lancefield classification of surface antigens
is bacterial sore throat, impetigo, cellulitis and necrotising fasciitis (strep A destroys connective tissue)

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How do drugs move into the skin?

if the drug is hydrophobic then it can move in by massive diffusion and remain in the lipid layer around the corneocytes

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How is the rate of drug absorption described mathematically?

by Fick’s Law according to the vehicle

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What is an excipient?

this is a substance that can be put in the vehicle that can enhance solubility

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What is a good way to administer a drug for a long time at a steady plasma concentration?

trans-dermal patch

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What is the best way to improve partitioning?

hydration of the skin by occlusion with type of vehicle or cling film
inclusion of excipients to increase solubility of the drug

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What effects do glucocorticoids have on the skin?

anti-inflammatory
immunosuppressive
vasoconstricting

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What conditions are glucocorticoids used to treat?

atopic eczema, psoriasis and pruritus

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What are the side-effects of long-term steroid use?

steroid rebound
skin atrophy
systemic effects
infection
steroid rosacea
stretch marks

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How do glucocorticoids act?

signal via GRalpha receptors
enter cells by diffusion and then they combine with GRa
the receptor moves to nucleus and assembles into a homodimer
binds to glucocorticoid response elements in the promoter region
switch on or off of genes

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What is TTD?

transdermal drug delivery is good for steady state drug delivery and avoids first-pass metabolism
however, only some drugs are suitable

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What are the + and - for subcutaneous drug administration?

+ slow absorption
+ slow constant release
- injection volume limited

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What are the advantages of topical treatments?

there is direct application and reduced systemic effects

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What are the disadvantages of topical treatments?

they are time consuming, correct dosage can be difficult and they are messy

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What are the features of creams?

non-greasy
semisolid emulsion of oil in water
high water content

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What are the features of ointments?

semi-solid grease or oil
no preservative
occlusive and restrict water loss from the skin
very greasy

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What are the features of lotions?

liquid
might sting
good for scalp or hair-bearing areas

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What are the features of gels?

thickened solutions
semi-solid
treat scalp, face and other hair-bearing areas

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What are the features of pastes?

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semi-solid
contain finely powdered material
stiff and greasy to hard to apply
protective, occlusive and hydrating

What are the features of foams?

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colloid with 2 or 3 phases
increased penetration of active agents
can spread easily

What are emollients?

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they enhance the rehydration of the epidermis for dry conditions esp eczema

What are the risks of emollients?

- skin is slippy | - risk of fire from paraffin content

What are the actions of topical steroids?

- vasoconstrictive - anti-inflammatory - antiproliferative

What are topical steroids used for?

- eczema - psoriasis - keloid scars - other non-infective dermatoses

How many grams of steroid for a whole adult?

20-30g

What are the most common side-effects of topical steroids?

- skin thinning - pupura - stretch marks - rosacea - acne - telangiectasia

What do calcineurin inhibitors do?

they suppress lymphocyte activation so are used in eczema treatment

What do antiseptics do?

they are used for recurrent infections, antibiotic resistance and wound irrigation

What are antiviral agents used for?

herpes simplex, herpes zoster and eczema herpeticum

What are topical antifungals used for?

candida, dermatophytes (ringworm) and pityriasis versicolor

What are keratolyticxs used for?

to soften keratin eg in corns or viral warts

What is the treatment for warts?

keratolytics and mechanical paring

What is the treatment for psoriasis?

emollients plus tar, vit D, keratolytic, topical steroid and dithranol

What can scalp psoriasis be treated with?

greasy ointments, tar shampoo, steroids in alcohol base or vet D analogues

What colours are the different types of Staph on agar plates?

- S.aureus is golden on agar | - Coagulase negative staph is white on agar

What is the only coagulase positive Staph?

S. aureus

What is the best drug for a Staph aureus infection?

flucloxacillin

What are two extra things that S. aureus can have that can make the infection worse?

- SSSST which is staphylococcal scalded skin syndrome toxin | - PVL producing staph is a worse infection due to toxins

What are some examples of skin diseases caused by staph aureus?

cellulitis, infected eczema or impetigo

What is the treatment for MRSA?

vancomycin | and co-trimoxazole or doxycycline

When should S.epidermidis be considered?

if it is in association with an implanted artificial material that is causing recurrence of infection

What is the most relevant strep to skin?

beta haemolytic (split into A and B based on antigenic structure)

What diseases are group A strep associated with?

infected eczema impetigo cellulitis

What is the classical disease caused by group A beta haemolytic strep?

erysipelas

When do you take swabs of an ulcer?

ONLY if there are signs of infection or cellulitis

What are the main features of a tinea infection?

- this is ringworm - found when the skin is soggy and it is in keratinised tissues - it heals from the inside out so gives a ring appearance - males

What is the most common microbiological cause of tinea?

trichophyton rubrum

What is the treatment for tinea?

clotrimazole cream or a topical nail paint

Where is candida usually seen and how is it treated?

- skin folds, under the breasts, nappy area of babies | - treatment is clotrimazole cream

What is the treatment for scabies?

malathion lotion

What is the most common cause of a UTI in a woman of child bearing age?

Staph saprophyticus

Microbiology and Pharmacology Flashcards

(54 cards)