Infections Flashcards
What is impetigo caused by?
A break in the skin leading to staph or strep pyogenes infection
Treatment of impetigo?
Hygeine
Small area: topical fusidic acid 5-7 days
Widespread oral flucloxacillin 7 days 500mg QDS
(alternative clarithromycin 250mg BD 5 days)
MRSA = mupirocin
Conjunctivitis causes and treatments
Viral, allergic, bacterial, chlamydial - self limiting. Often via unclean contact lenses etc.
- Self care
- Topical TOC antibiotics e.g. chloramphenicol 0.5% drops / 1% ointment - 5 days. 1-2 drops every 2 hours then QDS for the final 3 days.
Chloramphenicol MoA?
Interferes with bacterial ribosome and inhibition of protein synthesis - bacteriocidal
What are common organisms causing pneumonia?
Strep pneumoniae (pneumococcal) at risk patients
Or H.influezae
M. pneumoniae
S.aureus
What would be used to treat pneumonia caused by S.pneumoniae?
Amoxicillin, clarithromyin or doxycycline
What would be used to treat pneumonia caused by H.influenzae?
Amoxicillin, clarithromycin or co-amoxiclav
What organism causes a UTI?
E.coli
What are the 1st line treatments for an uncomplicated UTI?
Short course nitrofurantoin 100mg BD (MR)for 3 days (or 50mg QDS immediate release). DNA damage/free radicals
Or trimethoprim 200mg BD for 3 days. (inhibits folate synthesis)
How would treatment differ for a pregnant woman who has an uncomplicated UTI?
Nitrofurantoin is 1st line but not at term, used for 7 days
2nd choice - amoxicillin 500mg TDS 7 days
or can use cephalexin 500mg BD 7 days
What is the treatment for upper UTI - pyelonephritis?
Cephalexin 500mg BD 7-10 days
Ciprofloxacin 500mg BD 7 days
Co-amoxiclav 500/125mg BD 7-10 days
What are symptoms of upper UTI
Flank pain
High fever
What are symptoms of a lower uncomplicated UTI?
Dysuria
Urinary urgency & urinary frequency
cloudy / dark strange smelling urine
In older people - confusion, changes in behaviour
Who is more likely to get a UTI?
Younger sexually active women
Advice for someone who has conjunctivitis?
Wash hands regularly
bathe eyelids occasionally with warm water to remove discharge
When cleaning - wipe from bridge of nose to outer corner of eye with fresh piece of cotton wool
Protect eyes, sunglasses etc if allergic
Do not share towels/face clothes etc
Do not rub eyes
Do not wear contact lenses until better
Define antimicrobial stewardship
Overarching program to change and direct antimicrobial use at a healthcare institution- it is the optimal selection, dosage, duration that results in the best clinical outcome for that patient, with minimal toxicity and impact on AMR/ Focus on preserving antibiotic effectiveness through monitoring and judicious use, via formulary restrictions, audits, feedback, education, guidelines, strategies e.g. start smart then focus, target
Outline benefits of AMS in the healthcare system
Reduce the total use and inappropriate use to improve health outcomes and costs
- improve susceptibility profiles of hospital pathogens
- improve clinical markers e.g. length of stay, mortality
- reduce toxicity and adverse effects and no need to use less effective ABs, thus reducing morbidity
- patient safety
- more collaborative working between HCP in MDT
- transparency in prescribing practice, continuous education and learning from mistakes
- reduced risk of secondary infections e.g. injection sites, de-escalation
What are the main factors that make penicillins susceptible to acid hydrolysis? How to overcome these?
2x chemical things
1x biological
- ring strain - acids and nucleophiles open up the ring to relieve the strain, carbonyl group prone to Nu attack which breaks the ring - overcome this by storing as a powder until ready to dispense and keep in fridge
- amide side chain participates in the mechanism that opens the ring so nitrogen can donate it’s electrons that act as a nucleophile too to reduce - add an electron withdrawing group to reduce the nucleophilicity and electron density
- Beta lactamase enzymes opens the ring and hydrolyses. Can add bulky groups to side chain to reduce interaction with the enzyme. OR administer clavulanic acid to inhibit beta lactamase (irreversibly)
What is the mechanism of action of penicillins?
Inhibition of transpeptidase enzyme which stops the cross linking of the bacterial peptidoglycan cell wall.
What is 1st line for mild to moderate clostridium difficile?
Metronidazole 400mg TDS oral for 10-14 days
What is 1st line in severe c. diff?
Vancomycin 125mg QDS enterally 10-14 days
What drug can be used if recurrent C.diff
Fidaxomicin 200mg BD for 10 days
What is the treatment for bacterial vaginosis?
Oral metronidazole 400mg BD for 7 days
or 2g single dose
or topical gel 5g/night for 5 days
or clindamycin cream
Mechanism of action of metronidazole?
Nucleic acid/DNA synthesis interference due to nitroimidazole ring - reduced to nitro radicals by ferrodoxin- only works on anaerobic bacteria
