Bacteriology

Question 1

causative organism of cat scratch disease

Answer 1

bartonella spp
gram negative bacilli

Question 2

causative organism of cellulitis/osteomyelitis caused by animal bite

Answer 2

pasteurella multocida

Question 3

disease transmitted by aerosols of cattle/sheep or amniotic fluid

Answer 3

Q fever –> coxiella burnetii

Question 4

causative organism of Q fever

Answer 4

coxiella burnetii

Question 5

causative organism of rocky mountain spotted fever

Answer 5

ricketssia rickettsi

Question 6

source of transmission for rocky mountain spotted fever

Answer 6

ricketssia ricketssi –> dog tick (dermacentor)

Question 7

vector responsible for transmission of chagas disease

Answer 7

reduviid bug

Question 8

tabes dorsalis from tertiary syphyllis occurs due to damage to what spinal tract

Answer 8

dorsal column

Question 9

what type of pupil may be found in tertiary syphyllis

Answer 9

argyl robinson pupil

Question 10

treatment in nocardia vs actinomyces

Answer 10

‘treatment is a SNAP’
sulphonamides (co trim) - nocardia
actinomyces - penicillin

Question 11

difference in nocardia vs actinomyces presentations

Answer 11

nocardia causes pulmonary infections in immunocompromised patients, cutaneous infections after trauma which can spread to CNS = abscesses

actinomyces causes oral/facial abscesses that drain through sinus/tract, often associated with dental trauma. can also cause PID with IUD’s

Question 12

what do langhans giant cells in TB represent

Answer 12

secondary infection

Question 13

salmon coloured truncal rash (rose spots), initial constipation then diarrhoea, abdominal pain, bradycardia, fever, progression to GI haemorrhage and ulceration

Answer 13

typhoid fever (salmonella typhi)

Question 14

what can cause false positive results on non-treponemal specific testing for syphillis

Answer 14

pregnancy
viral infections (e.g. EBV, hepatitis)
drugs (chlorpromazine, procanamide)
rheumatic fever
lupus (anti-cardiolipin Ab) nd leprosy

Question 15

testing available for syphillis

Answer 15

serological tests;
non-treponema specific - VDRL, RPR
treponema specific - FTA-ABS, TP-PA

direct testing;
- darkfield microscopy
- PCR

Question 16

after treating syphillis will antiodies still be present on serological testing

Answer 16

Non-treponema tests will become negative, treponema tests will remain positive

Ab wont be present on non-treponema tests i.e. VDRL and RPR
Ab will still be present on treponema specific tests i.e. FTA-ABS, TP-PA

Question 17

presentation of rickettsia typhus

Answer 17

rash starts centrally then spreads outwards sparing the hands and feet (unlike rickettsia rickettsi - spotty mountain fever)

Question 18

rickettsial organisms and vector for typhus

Answer 18

endemic - fleas, rickettsia typhi
epidemic- human body louse, rickettsia prowazekii

Question 19

common cause of culture negative endocarditis

Answer 19

coxiella burnettis - Q fever

Question 20

vector for Q fever

Answer 20

no vector

Question 21

flu like symptoms, headache, cough, pneumonia, hepatitis

Answer 21

Q fever

Question 22

comma or S shaped organism, grows at 42 degrees, causes diarrhoea

Answer 22

campylobacter

Question 23

bloody diarrhoea, liver abscess

Answer 23

E. histolytica

Question 24

day care outbreaks, pseduoappendicitis

Answer 24

Y enterocolitica

Question 25

causative organism - painful genital ulcer may bleed and inguinal lymphadenopathy

Answer 25

chancroid - haemophillus ducreyi

Question 26

causative organism - painless beefy red ulcer that bleeds readily on contact

Answer 26

granuloma inguinale = klebsiella

Question 27

what UTI causing organism shows 'swarming' on agar due to motility

Answer 27

proteus

Question 28

plasmodium falciparum on blood smear

Answer 28

trophozoite ring within RBC and crescent shaped gametocytes

Question 29

what condition may bring about a false negative PPD result

Answer 29

PPD positive in past or current TB infection PPD = no TB infection or false negative in immunocompromised patients (esp low CD4 counts)

Question 30

virulence factor h. influenzae

Answer 30

virulent capsule

Question 31

virulence factor e. coli

Answer 31

type 3 secretion system, haemolysins and fimbrae

Question 32

during what stage of chlamydia cell cycle does it become infectious

Answer 32

extracellular elementary body

Question 33

gram positive spore forming anaerobe

Answer 33

c.diff

Question 34

shigella invades immune system via what cells

Answer 34

microfold cells

Question 35

virulence factor for TB

Answer 35

activates macrophages and induces release of TNF alpha major glycolipid in bacterial cell wall called cord factor

Question 36

virulence factor of h. influenza and strep pneumoniae

Answer 36

cleavage of IgA

Question 37

contracted from southwestern USA. Fever, night sweats, arthralgia, cough, erythema nodosum or multiforme

Answer 37

coccidiodomycosis immitis

Question 38

disease which causes migratory arthritis after GAB infection and mechanism of infection

Answer 38

rheumatic fever antibody cross reactivity against foreign and host immune systems

Question 39

genomic structure of h. duceuyi

Answer 39

gram negative diplococcus

Question 40

fever, sore throat, cervical lymphadenopathy, grey/whitish plaque on pharynx which isnt scrappable

Answer 40

diptheria cultured on loffler or tellurite medium

Question 41

how to exotoxin produced by diptheria cause symptoms

Answer 41

adenosine diphosphate ribosylation of elongation factor 2

Question 42

causative organism of infection from indwelling medical devices

Answer 42

staph epidermidis, enterococcus

Question 43

grows on bile esculin agar

Answer 43

enterococcus (gram positive, catalase negative, group A strep, optochin negative)

Question 44

vaccine causes antibody production against polyribosylribitol and phosphate type b capsule

Answer 44

h. influenza

Question 45

most common causative organism of infective endocarditis in patients on dialysis and IVDU

Answer 45

staph aureus

Question 46

haemolysin virulence factor

Answer 46

staph aureus

Question 47

h. influenza virulence factor

Answer 47

virulent capsule + cleavage of IgA

Question 48

single stranded, negative sense, linear, non- segmented RNA

Answer 48

paramyxoviruses (enveloped and helical)

Question 49

what part of the epithelium does HPV affect

Answer 49

stratum basale

Question 50

what virus is a risk factor for non-hodgkins lymphoma

Answer 50

hepatitic C

Question 51

latency in mononuclear cells

Answer 51

CMV pneumonitis - histology shows large cells with internuclear inclusions 'owl eyes' - double stranded linear DNA virus

Question 52

activation of guanylate cyclase leading to increased intracellular cGMP

Answer 52

e.coli (travellers diarrhoea)

Question 53

production of leithinase causing cell membrane destruction

Answer 53

alpha toxin by clostridium perfringes

Question 54

genomic structure of the causative organism of cat scratch disease

Answer 54

bartonella spp. gram negative bacilli

Question 55

gram negative baccilus responsible for infection after rat bite

Answer 55

streptobacillus moniliformis

Question 56

genomic structure of clostridium botulism

Answer 56

gram positive, spore forming anaerobic bacilli

Question 57

tennis racket appearance on microscopy

Answer 57

clostridium botulism (gram positive, rods spore forming anaerobe)

Question 58

virulence factor of cryptococcus neoformans

Answer 58

polysacharide capsule formation

Question 59

causative organism of meningitis after exposure to pigeon droppings

Answer 59

cryptococcus neoformans

Question 60

corkscrew shaped spirochete

Answer 60

borrelia burgdorferi

Question 61

cyclical fevers and recent travel

Answer 61

plasmodium falciparum

Question 62

UTI negative for nitrite and grows on bile esculin agar

Answer 62

enterococcus

Question 63

toxin produced by what bacteria works by inactivating ribosomes

Answer 63

shigella and e.coli

Question 64

toxin produced by what bacteria acts by over stimulating adenylate cyclase

Answer 64

bordetella pertusis

Question 65

what is the infective form of toxoplasmosis gondii

Answer 65

tachyzoites (bradyzoites are non transmittable and represent chronic infection)