Microbiology

Question 1

how is bacterial grown and assessed?

Answer 1

agar based medium
microscopy

Question 2

types of agar media?

Answer 2

enriched/unenriched
selective/unselective
differential/undifferential

Question 3

what is enriched agar used for?

Answer 3

bacteria that only grows in specially fortified media

Question 4

what is selective agar used for?

Answer 4

contains compounds that inhibit growth of some non pathogenic bacteria

e.g faeces/genital samples to distinguish from normal flora

Question 5

what is differential agar used for?

Answer 5

colour indicators so different types of bacteria in sample are seen via different colours

Question 6

what are staphylococci?

Answer 6

gram +ve cocci

Question 7

how is staph aureus seen in the lab?

Answer 7

produces a coagulase enzyme that causes serum to clot

Question 8

what bacteria produces an exotoxin?

Answer 8

s aureus

Question 9

how do penicillins work?

Answer 9

beta lactam

act on peptidoglycan molecule in cell wall

Question 10

action of mRSA?

Answer 10

penicillin binding protein in cell wall
resistant to all beta lactam Abx

Question 11

features of strep/enterococci?

Answer 11

gram +ve
chains

Question 12

types of streptoccoi?

Answer 12

alpha - complete haemolysis of red cells in agar

beta - partial haemolysis of red cells in agar (green/brown)

gamma - no haemolysis of red cells in agar

Question 13

names of gram +ve rods?

Answer 13

nocardia
actinomyces

Question 14

who gets nocardia infections? features?

Answer 14

immunocompromised

brain abcess
suppurative lung infection

Question 15

e.g of gram positive bacilli?

Answer 15

corynebacteria (causes diptheria)

Question 16

listeria monocytogenes -type of bacteria?

Answer 16

corynebacteria
aerobic gram +ve bacilli

Question 17

who gets listeria monocytogenes infections?

Answer 17

meningitis if immunocompromised

Question 18

what effect can listeria monocytogenes have in pregnancy?

Answer 18

cross placenta and cause miscarriage/PTL/meningitis

avoid pate and soft cheese

Question 19

aerobic gram negative rod e.g?

Answer 19

Enterobacteriaeceae
Pseudomonas

penicillin resistant

Question 20

aerobic gram negative cocci e.g?

Answer 20

Neisseriae

Question 21

where do anaerobic organisms commonly live? structure?

Answer 21

gut and oral cavity

gram -ve rods

Question 22

diagnosis of syphylis?

Answer 22

serosal tests
cannot be cultured

Question 23

how to test for active or old syphilis infection?

Answer 23

active/recent - IgM

disease activity - VDRL

Question 24

what causes q fever?

Answer 24

coxiella burnetti

Question 25

features of chlamydia?

Answer 25

gram negative anaerobic coccobacillus

Question 26

Ix for chlamydia?

Answer 26

NAAT

Question 27

Ways to detect viral infection?

Answer 27

electron microscopy tissue culture enzyme immunoassay fluorescence microscopy PCR

Question 28

are herpes viruses enveloped? e.g

Answer 28

yes HSV CMV VZV

Question 29

features if fetus infected with VZV in utero?

Answer 29

scarring limb hypoplasia

Question 30

features if fetus infected with CMV in utero?

Answer 30

IUGR fever SN hearing loss seizures jaundice pneumonitis thrombocytopenia

Question 31

hep A spread? Ix?

Answer 31

faeco oral IgM in serum

Question 32

what type of virus is hepatitis?

Answer 32

RNA virus Hep B is an enveloped DNA virus

Question 33

tests for hep B?

Answer 33

HBsAg - active infection antibodies to HBsAG - previous exposure, non infective HBcAg - previously infection, not present in vaccinated e antigen - high levels = infective HBeAg - low infectivity

Question 34

features of parvovirus b19?

Answer 34

single stranded DNA virus

Question 35

what happens to fetus if infected with parvovirus?

Answer 35

anaemia hydrops fetalis

Question 36

features of congenital rubella?

Answer 36

deafness cataracts microcephaly cardiac abnormalities

Question 37

features of HIV?

Answer 37

retrovirus has reverse transcriptase - can transcribe itself into host cell DNA

Question 38

what is a facultative bacteria?

Answer 38

facultative anaerobes can live with or without oxygen, but grow better with it

Question 39

what is an obligate bacteria?

Answer 39

Obligate anaerobes must live in an oxygen-free environment

Question 40

how is fetal CMV diagnosed?

Answer 40

amniocentesis (after 21wks)

Question 41

features of fetal toxoplasmosis infection?

Answer 41

hydrocephalus microcephaly anaemia thrombocytopenia opthalmic defects

Question 42

features of fetal rubella infection?

Answer 42

opthalmic VSD CNS delay thrombocytopenia

Question 43

what infections can lead to congenital abnormalities?

Answer 43

TORCH toxoplasmnosis other organisms Rubella CMV Herpes simplex

Question 44

most common cause of genital herpes?

Answer 44

HSV 2

Question 45

types of neonatal herpes infection?

Answer 45

restricted to skin/superficial CNS disseminated

Question 46

Tx of genital herpes in pregnancy?

Answer 46

400mg aciclovir tds for 5/7 400mg TDS daily until delivery

Question 47

what viral load in HIV is a vaginal delivery allowed?

Answer 47

<50

Question 48

what cell does HIV infect?

Answer 48

CD4

Question 49

when do infants get 2 weeks of ART if HIV +ve mother?

Answer 49

cART for longer than 10 weeks + two viral loads <50 4 weeks apart + viral load <50 at 36 weeks

Question 50

What HPV causes cancers?

Answer 50

HPV 16 + 18

Question 51

what HPV causes anogenital warts?

Answer 51

HPV 6 + 11

Question 52

how does listeria affect pregnancy women?

Answer 52

chorioaminitis placental necrosis miscarriage stillbirth

Question 53

how long is VZV infective for?

Answer 53

48hrs before rash to vesicles crusting

Question 54

what to do if pregnant woman exposed to VZV?

Answer 54

maternal blood for varicella IG PEP if not immune (aciclovir) or VZIG

Question 55

what to do if pregnant woman presents with rash in VZV?

Answer 55

aciclovir if 24hrs from onset of rash

Question 56

advice if people have travelled to a Zika country and are planning to conceive?

Answer 56

male - avoid UPSI for 3/12 female - avoid UPSI for 2/12

Question 57

rubella incubation period?

Answer 57

14 days

Question 58

what type of virus is a zika virus?

Answer 58

single stranded RNA

Question 59

risks to baby of VZV?

Answer 59

2% if before 20 weeks 50% last 4 weeks of pregnancy

Question 60

scarlet fever incubation period?

Answer 60

1-7 days

Question 61

chickenpox incubation period?

Answer 61

14 days

Question 62

flu incubation period?

Answer 62

1-3 days

Question 63

parvovirus incubation period?

Answer 63

4-20 days

Question 64

treatment for toxoplasmosis?

Answer 64

spiramycin if +ve amniotic fluid PCR - pyrimethamine

Question 65

what treatment for warts is not safe in pregnancy?

Answer 65

podophylline paint 5-fluorouracil

Question 66

% of patients that produce antibodies following HPV infection?

Answer 66

50%

Question 67

rate of HIV in uk obstetric population?

Answer 67

2 per 1000

Question 68

rate of clearing HPV infection?

Answer 68

70% in 1 year 90% in 2 years

Question 69

what gestation puts you at risk of fetal varicella syndrome? %risk?

Answer 69

within first 28 weeks 0.4% in 1-12 weeks 2.0% in 12-20weeks

Question 70

mortality rate for listeria infection in newborns?

Answer 70

25%

Question 71

only double stranded RNA virus?

Answer 71

rotavirus

Question 72

incubation period for CMV?

Answer 72

3-12weeks

Question 73

what onco proteins are associated with high risk HPV?

Answer 73

E6 and E7

Question 74

who should get GBS treatment in labour?

Answer 74

+ve swab previous GBS neonatal disease (even if repeat swabs -ve)

Question 75

what are the live vaccines?

Answer 75

polio mumps measles rubella yellow fever VZV