Lecture 10 - chemoprophylaxis Flashcards
Define chemoprophylaxis
The use of an antimicrobial drug to prevent infection
When should chemoprophylaxis be considered?
- significant risk of infection with serious consequences
- cause of infection and Abx sensitivity predictable
- cheap and safe Abx available
Name some disadvantages of chemoprophylaxis
- Disturb normal human flora
- Side effects and drug interactions
- Can cause colonisation with more Abx resistant bacteria
- Cost
When is prophylaxis for malaria particuarly neccessary
pregnancy and patients with a splenectomy
When is group B strep infection common
during labour as part of vaginal flora. particular risk for pre-term babies or low birth weight infants
When is prophylaxis necessary for Group B strep
pre term labour, ruptured membranes, history of infection in previous pregnancies, or mother known to be carrying
When is prophylaxis for Group A invasive strep necessary
if either mother or baby develops infection in neonatal period must use prophylaxis on the other AND for all household if 2 or more cases in 30 days
What is rheumatic fever?
Immunological response to infection with strep pyogenes (Gr A Strep) - 2-3 weeks after initial saw throat you get carditis and heart valve damage, joint inflammation, rashes and chorea
Why is long periods of penicillin prophylaxis routine in rheumatic fever?
penicillin resistance has never been reports in a Group A strep
What happens if individuals are prone to repeated rheumatic fever attacks?
progressive valvular heart damage
Which meningitis strains are immunised against
Meningococcal group C is nationally immunised. Quadrivalent vaccines against ACWY are also available
Men B is also recently available but not national programme
Who receives prophylaxis after a case of meningococcal meningitis?
kissing contacts, mouth to mouth resus, same house (e.g. in halls if few cases whole halls vaccinated)
What is Hib and what can it cause?
haemophilus influenzae can cause meningitis, mainly in the under 4’s
Who is vaccinated in cases of Hib
ALL household contacts if the house contains a child under 4 who is unvaccinated
What does prophylaxis against TB achieve
eradication of the dormant disease before the active form becomes apaprent
Which cases would receive a TB vaccination
children under 16 who are found to be TB positive:
- on new immigrant screens
- school BCG programe
- contact tracing of an index case
and neonates under 2 who are in close contact with a smear positive case
adults with recent Tb seroconversion
threats of MDR TB
What is diphtheria? where is it usually found?
1) infection with corynebacterium duptheriae - causes severe saw throat, bacteria releases toxins causing complications to heart and CNS
2) eastern europe, asia, africa - risk to travellers
When is diphtheria vaccines given?
after one case - to prevent a second. given to non-immune close contacts. immunised just get booster
What is pertussis?
persistant paroxysmal cough (whooping cough) serious in young children