microbio

Question 1

commonest causative organism of exacerbation of COPD

Answer 1

Haemophilus influenzae (most common cause)
Streptococcus pneumoniae
Moraxella catarrhalis

30% viral

Question 2

normal flora of the mouth

Answer 2

strep viridans
neisseria sp
anaerobes

candida sp (few)
staphylococci

Question 3

strep pyogenes

Answer 3

Group A Streptococcus (GAS)
gram positive
catalase negative
beta haemolysis *

lancefield classification = surface antigen

Question 4

beta haemolytic strep

Answer 4

(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

Question 5

alpha haemolytic strep

Answer 5

(partial haemolysis)
- strep pneumonia
- strep viridans

Question 6

what conditions is strep pyogenes responsible for?

Answer 6

erysipleas
impetigo
necrotising fasciitis
pharygitis/tonsilitis

immunological reactions can cause rheumativ fever or post-strep glomerulonephritis

Question 7

when to refer a sore throat

Answer 7

stridor
breathing difficulty
clinical dehydration
systemically unwell

Question 8

infections of middle ear, most common bacteria + diagnosis

Answer 8

often viral with bacterial secondary infection
- haemophilus influenza
- strep pneumoniae
- strep pyogenes

swab of pus if eardrum perforates

Question 9

management of otitis media

Answer 9

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

Question 10

management of acute sinusitis

Answer 10

av. illness length = 2.5wks
- antibiotics for severe/deteriorating cases of >10days

1st = phenoxymethylpenicillin
2nd = doxycycline NOT IN KIDS

Question 11

treatment of bacterial conjunctivitis

Answer 11

chloramphenical
- avoid in hx of aplastic anaemia or allergy
- be aware of allergy in worsening symptoms

topic fusidic acid in pregnancy

Question 12

viral causes of conjuntivitis

Answer 12

adenovirus
herpes simplex
herpes zoster - along dermatome

viral - serous discharge, recent URTI, preauricular lymph nodes

Question 13

herpes zoster ophthalmicus

Answer 13

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

Question 14

what “breed” is trichomonas vaginalis?

Answer 14

parasite

Question 15

candida infection

Answer 15

intensely itchy
clinical diagnosis, mostly cause by C.albicans

Mx = tropical clotrimazole pessay or cream (available OTC), oral fluconazole

Question 16

acute bacterial prostatitis

Answer 16

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

Question 17

normal vaginal flora

Answer 17

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)

Question 18

hydrogen peroxide producing lactobacilli

Answer 18

lactobacillus crispatus

Question 19

pubic lice

Answer 19

(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

Question 20

management of pubic lice

Answer 20

malathion lotion

Question 21

blood picture most likely assoc with positive EBV

Answer 21

WCC raised
lymphocytes raised
ALT low
CRP massively raised

Question 22

which common drug interacts with macrolides

Answer 22

STATINs

macrolides - clarithromycin, erythromycin, azithromycin

Question 23

antibiotics and contraception

Answer 23

antibiotics can cause GI upset - which can affect absorption of contraception