microbio Flashcards
commonest causative organism of exacerbation of COPD
Haemophilus influenzae (most common cause)
Streptococcus pneumoniae
Moraxella catarrhalis
30% viral
normal flora of the mouth
strep viridans
neisseria sp
anaerobes
candida sp (few)
staphylococci
strep pyogenes
Group A Streptococcus (GAS)
gram positive
catalase negative
beta haemolysis *
lancefield classification = surface antigen
beta haemolytic strep
(complete haemolysis) subdivided into groups A-H, only A, B + D important in humans
group A - strep pyogenes
group B - strep agalactiae, neonatal meningitis
group D - enterococcus
alpha haemolytic strep
(partial haemolysis)
- strep pneumonia
- strep viridans
what conditions is strep pyogenes responsible for?
erysipleas
impetigo
necrotising fasciitis
pharygitis/tonsilitis
immunological reactions can cause rheumativ fever or post-strep glomerulonephritis
when to refer a sore throat
stridor
breathing difficulty
clinical dehydration
systemically unwell
infections of middle ear, most common bacteria + diagnosis
often viral with bacterial secondary infection
- haemophilus influenza
- strep pneumoniae
- strep pyogenes
swab of pus if eardrum perforates
management of otitis media
80% resolve in 4 days without antibiotics
1st - amoxicillin(5days), erythromycin is pen allergic
give Ab immediately if
- more than 4 days or not improving
- <2 with bilateral otitis media
- otitis media with perforation
- immunocompromised
management of acute sinusitis
av. illness length = 2.5wks
- antibiotics for severe/deteriorating cases of >10days
1st = phenoxymethylpenicillin
2nd = doxycycline NOT IN KIDS
treatment of bacterial conjunctivitis
chloramphenical
- avoid in hx of aplastic anaemia or allergy
- be aware of allergy in worsening symptoms
topic fusidic acid in pregnancy
viral causes of conjuntivitis
adenovirus
herpes simplex
herpes zoster - along dermatome
viral - serous discharge, recent URTI, preauricular lymph nodes
herpes zoster ophthalmicus
reactivation of varicella zoster virus in area supplied by ophthalamic division of trigeminal nerve
- vesicular rash around eye
- hutchinsons sign - rash at tip of nose,
Mx = oral antiviral for 7-10days
what “breed” is trichomonas vaginalis?
parasite
candida infection
intensely itchy
clinical diagnosis, mostly cause by C.albicans
Mx = tropical clotrimazole pessay or cream (available OTC), oral fluconazole
acute bacterial prostatitis
symptoms of UTI but may have lower abdo pain
tender prostate on exam
rare complication of UTI
diagnosis - clincal signs + MSSU for C&S (+/- first pass urine for chlamydia/gonorrhoea)
Mx = ofloxacin/ciprofloxacin for 28days, trimethoprim if high C diff risk
normal vaginal flora
lacobacillus sp predominate in the healthy vagina + produces - lactic acid +/- hydrogen peroxide (suppress growth or other bacteria)
other organisms
- strep viridans
- group B beta haemolytic strep
- candida sp (in small numbers)
hydrogen peroxide producing lactobacilli
lactobacillus crispatus
pubic lice
(phthirus pubis)
- acquired by close genital skin contact
- lice bt skin + feed on blood, causes itching in pubic area
- female louse lays eggs on hair next to skin
males on avergae live for 22ddays, female for 17
management of pubic lice
malathion lotion
blood picture most likely assoc with positive EBV
WCC raised
lymphocytes raised
ALT low
CRP massively raised
which common drug interacts with macrolides
STATINs
macrolides - clarithromycin, erythromycin, azithromycin
antibiotics and contraception
antibiotics can cause GI upset - which can affect absorption of contraception
