Past papers 2

Question 1

Components of cell walls

• NAG
• Lipid A
• Ergosterols
• Mycolic acid

1. LPS
2. Mycobacteria
3. Fungi
4. Peptidoglycan

Answer 1

1. LPS
   Lipid A - endotoxin
2. Mycobacteria
   Mycolic acid
3. Fungi
   Ergosterol
4. Peptidoglycan
   The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)

Question 2

Identification of organisms

• Modified Zn stain
• Thin blood film – Giemsa stain
• Concentrated iodine
• Calcofluor white stain

1. Filamentous fungi on BAL
2. Cryptosporidium
3. Ova in stool
4. Malaria

Answer 2

1. Filamentous fungi on BAL
   Calcofluor white stain - used to stain yeasts
2. Cryptosporidium
   Modified Zn stain
3. Ova in stool
   Concentrated iodine
4. Malaria
   Thin blood film – Giemsa stain

Question 3

patient with HIV cryptococcal meningitis was treated with caspofungin. Why is this is bad choice?

poor CSF penetration
too expensive
crypto resistant
contradicted in AIDS

Answer 3

Echinocandins are ineffective against cryptococcal

Another similar question exists with answer:
- cryptococcus is resistant to echinocandins as it does not contain 1,3 beta-d-glucan synthase

Cryptococcus does contain 1,3 beta-d-glucan synthase, but resistance is intrinsic by other means

Correct answer in that example is poor CSF penetration

Question 4

Match the following organisms with the clinical pictures

Neisseria gonorrhea
chlamydia trachomatis
candida albicans
treponema pallidum
haemophilus ducreyi
calymmobacterium granulomatis
ureaplasma urealyticum
trichomonaas vaginalis

1. A 20 year old man presents with dysuria and uretheral discharge.A gram stained smear of a uretheral swab shows numerous pus calls but no organisms were detected
2. A 34 year old man returning from Thailand where he had unprotected sex presents with a painless ulcer on his penis
3. A 24 year old woman presents with arthritis and skin rash
4. A 30 year old pregnant woman presents with itch and soreness and a thick white discharge
5. A recent immigrant from Africa presents with a painful ulcer on his penis which bleeds on touch associated with tender enlarged inguinal lymph nodes, bacteriologic smear and culture were done but they were not helpful.

Answer 4

1. A 20 year old man presents with dysuria and uretheral discharge.A gram stained smear of a uretheral swab shows numerous pus calls but no organisms were detected
   Chlamydia trachomatis
2. A 34 year old man returning from Thailand where he had unprotected sex presents with a painless ulcer on his penis
   treponema pallidum
3. A 24 year old woman presents with arthritis and skin rash
   Neisseria gonorrhoea
4. A 30 year old pregnant woman presents with itch and soreness and a thick white discharge
   trichomonas vaginalis - thick white discharge
   candida albicans - usually cottage cheese
   Bacterial Vaginosis - Gardnerella. Usually fishy smell
5. A recent immigrant from Africa presents with a painful ulcer on his penis which bleeds on touch associated with tender enlarged inguinal lymph nodes, bacteriologic smear and culture were done but they were not helpful.
   haemophilus ducreyi

Question 5

32wks pregnant lady with confirmed rubella.

Advice:
termination of pregnancy
child likely to be born with severe deformities
no risk of infection to fetus
risk of infection present, but deformities rare

Answer 5

risk of infection present, but deformities rare

No risk of documented abnormalities if infection occurs after 20 weeks

Question 6

Woman develops rubella infection 8 days into pregnancy – what are the consequences for the foetus?

Answer 6

Miscarriage/ stillbirth

microcephaly

cardiac disease

visual problems e.g cataracts

Deafness

Question 7

Pregnant woman is both HBV and HCV positive. Her newborn baby should receive the following treatment?

• Zidovudine
• Human Hep B immune globulin and full Hep B vaccination
• Human immune globulin only
• Interferon

Answer 7

Human Hep B immune globulin and full Hep B vaccination

Question 8

Congenital infections.

• Toxoplasma gondii
• Chlamydia trachomatis
• Rubella
• Listeria monocytogenes
• CMV
• Treponema pallidum
• Parvovirus B19

1. Pregnant woman had flu-like illness which is followed by a septic abortion. Autopsy of infant shows granulomas in liver
2. A baby born with IUGR and hepatosplenomegaly
3. A pregnant woman develops fetal hydrops on ultrasound
4. A 2 month old infant presents with conjunctivitis and pneumonia

Answer 8

1. Pregnant woman had flu-like illness which is followed by a septic abortion. Autopsy of infant shows granulomas in liver
   Toxoplasma
2. A baby born with IUGR and hepatosplenomegaly
   CMV
3. A pregnant woman develops fetal hydrops on ultrasound
   Parvovirus B19
4. A 2 month old infant presents with conjunctivitis and pneumonia
   Chlamydia trachomatis

Question 9

18. A pregnant woman, 12 weeks gestation, is picked up at antenatal screening as HIV+ve. CD4 count is 500, viral load is 9000, the patient is asymptomatic and clinically well. Which of the following is the most correct?

a) Perform amniocentesis to detect whether the baby is infected
b) Do nothing and treat the baby after birth
c) Commence short-term antiretroviral therapy from the second trimester
d) A Ceasarian section is virtually unavoidable

Answer 9

Commence short-term antiretroviral therapy from the second trimester

Mother should then continue long term ARV - new evidence that should be on ARV regardless of CD4 count

Baby should get ARV e.g zidovudine

Question 10

HBIG
HBIG and hep B vaccination
High dose hep B vaccination
VZIG
VZIG plus vaccination
VZV vaccination
HNIG
Do nothing

1. Baby of hep B eAg positive mother
2. Neonate whose mother developes chickenpox 2 days post delivery
3. Non-immune pregnant woman in contact with measles
4. CRF patient, not currently on dialysis but who will be commencing dialysis in the near future
5. Non-pregnant paediatric nurse, is not varicella immune, who has been looking after her mother with ophthalmic zoster

Answer 10

1. Baby of hep B eAg positive mother
   HBIG and hep B vaccination
2. Neonate whose mother develops chickenpox 2 days post delivery
   VZIG - no cross-placenta antibody transfer. Give up to 7 days old
3. Non-immune pregnant woman in contact with measles
   HNIG
4. CRF patient, not currently on dialysis but who will be commencing dialysis in the near future
   High dose hep B vaccination
5. Non-pregnant paediatric nurse, is not varicella immune, who has been looking after her mother with ophthalmic zoster
   VZV vaccination - occupational exposure

Question 11

Pregnant woman 14 weeks, concerned re risk of toxoplasma and present to GP for testing. Results show weak positive IgM, positive IgG, predominantly
high avidity. What should she be advised?

Pregnancy likely to be severely affected and advise termination

Baby should receive sulphadiazine and pyrimethamine after delivery

Mother should receive sulphadiazine and pyrimethamine for duration of pregnancy

Mother should receive spiramycin for duration of pregnancy, baby is unlikely to be affected

Answer 11

spiramycin is recommended for women whose infections were acquired and diagnosed before 18 weeks gestation and infection of the fetus is not documented or suspected. Spiramycin acts to reduce transmission to the fetus and is most effective if initiated within 8 weeks of seroconversion. 40% of primary infection in pregnancy will infect foetus

Congenitally infected newborns are generally treated with pyrimethamine, a sulfonamide, and leucovorin for 12 months.

spiramycin is a macrolide

Question 12

Pregnant woman tests positive for toxoplasma in pregnancy.

May present with flu-like illness, lymhadenopathy

What are risks to foetus?

Answer 12

Miscarriage
hydrocephalus
retinchoroiditis

Question 13

Pregnant woman tests positive for toxoplasma in pregnancy.

What is treatment?

Answer 13

If diagnosed before 18 weeks gestation - Spiramycin to reduce risk of transmission.

USS/ choriamniocentesis - assess if baby affected. If affected, start pyremethamine/ sulphadiazine/ folinic acid for treatment (stop spiramycin)

Question 14

Does toxoplasma infection always need treated?

Answer 14

Treat if immunocompromised, or pregnant

If otherwise well, after flu-like illness, toxoplasma will form cysts, and symptoms will resolve. Will only reactivate if become immunocompromised

Question 15

Pregnant women 18 weeks, brings child who has
chickenpox to GP. Mother is
sure she has not had VZV. What should the GP do?

a. Issue prophylactic acyclovir
b. Issue VZIG
c. Test for VZV IgM
d. Test for VZV IgG

Answer 15

Test for VZV IgG ??

If non-immune, offer VZIG within 10 days

Question 16

A pregnant woman returns from India and dies shortly after her return of an acute illness. Which of the following is most likely the cause?

	Brucella
	Typhus
	Hep A
	Hep D
	Hep E

Answer 16

HEV

Question 17

1. A baby born to mother with primary CMV infection in pregnancy is detected to have 20000 copies/ml CMV in urine 2 days after birth. The most appropriate management strategy is:

a. Reassure and do nothing
b. Treat with IV Aciclovir for 2 weeks
c. Treat with IV Ganciclovir for 2 weeks
d. Refer for audiology assessment
e. Check CMV IgM in baby

Answer 17

Refer for audiology

If baby is well, and audiology/ brain imaging normal, then likely do not need to treat.

Aciclovir incorrect
Ganciclovir - should be for 6 months
IgM incorrect

Question 18

A 24 week pregnant staff nurse sustains a needlestick from a HBSag positive patient who is HbEag positive. She has received 3 HBV immunisations in the past, and anti HBS level is < 10. The correct management is:

a. Give HBV vaccine dose and HBIG
b. Give infant HBIG at birth
c. Do nothing
d. Treat with Lamivudine

Answer 18

Give HBV vaccine dose and HBIG

Question 19

Pregnant woman (36 weeks) suffers a rash illness, then presents to GP. 
Blood taken shows: Rubella IgG positive, IgM negative, Parvovirus IgG positive, IgM positive. What is the most likely outcome?

a. Normal healthy child
b. intra-uterine death
c. congenital rubella syndrome,
d. Hydropsfetalis

Answer 19

normal healthy baby

No risk of documented abnormalities if infection occurs after 20 weeks

Question 20

A pregnant woman (32 weeks gestation) present with painful ulcer on her vagina. HSV2 PCR comes back positive. What would be you action?

Treat with acyclovir and treat baby
tell her all will be fine
treat with acyclovir and consider elective caesarian
measure HSV2 antibody to see if it is primary infection deliver by emergency section

Answer 20

treat with aciclovir, and consider elective caesarian section

Question 21

45yrs old male,travels to Mexico, presenting with a rash followed by pneumonia

CXR: cavitating lesion.

Cause?

Answer 21

Coccidioides

Question 22

Child with rash on face and shoulders. Then develops desquamation of palms /soles

what is cause?

Answer 22

GAS - Scarlet fever

Question 23

Child with conjunctivitis, then develops pneumonia.

What are potential causes?

Answer 23

Chlamydia trachoamtis - neonatal

Measles

Question 24

Scaly rash with skin depigmentation, microscopy shows yeasts and small hyphae:

Trichophyton
Microsporum
candida
M. furfur

Answer 24

M furfur - pityriasis versicolor

Question 25

What is pediculus humanus?

Answer 25

Human louse

Question 26

``` A. Herpes zoster B. Herpetic whitlow C. Hot tub folliculitis D Cat scratch E. Kawasaki F. Lyme Disease G. Erysipelothroid H. Sporothricosis I. Herpangina ``` Which is the most accurate presentation: 1. Large salmon coloured lesion of erythema migrans with central clearing due to tick bite 2. Disease of childhood, lesions in mouth which become vesicular with a grey base and punched out edge 3. Desquamation and prominent papillations on the tongue 4. Vesicular rash with pustular lesions, erythema and painful swelling of the digits 5. Migrating lymphacutaneous lesions in thigh of young man following dirt bike accident

Answer 26

1. Large salmon coloured lesion of erythema migrans with central clearing due to tick bite Lyme disease 2. Disease of childhood, lesions in mouth which become vesicular with a grey base and punched out edge Herpangina - also called mouth blisters. Coxsackie virus 3. Desquamation and prominent papillations on the tongue Kawasaki 4. Vesicular rash with pustular lesions, erythema and painful swelling of the digits Herpetic whitlow 5. Migrating lymphacutaneous lesions in thigh of young man following dirt bike accident Sporotrichosis

Question 27

``` A. Herpes zoster B. Herpetic whitlow C. Hot tub folliculitis D Cat scratch E. Kawasaki F. Lyme Disease G. Erysipelothroid H. Sporothricosis I. Herpangina ``` 6. Vesicular rash with dermatomal distribution 7. Acute self limiting infection due to Pseudomonas aeruginosa 8. Maculopapular lesions on fingers after cleaning fish 9. Prominent cervical lymphadenopathy and primary inoculation lesion

Answer 27

6. Vesicular rash with dermatomal distribution Herpes Zoster 7. Acute self limiting infection due to Pseudomonas aeruginosa Hot tub folliculitis 8. Maculopapular lesions on fingers after cleaning fish Erysipelothroid 9. Prominent cervical lymphadenopathy and primary inoculation lesion Cat scratch disease

Question 28

Fisherman's wife presents with cellulitis of one finger. What is possible cause?

Answer 28

Eryispelothrix Gram pos bacilli Infection in humans is often occupationally related, occurring most frequently in people whose jobs are closely related to contaminated animals, their products, wastes, or soil. Butchers, abattoir workers, veterinarians, farmers, fishermen, and fish-handlers are at highest risk of infection.

Question 29

``` Rashes a- Roseola infantum b- Erythema infectiosum c- Scarlet fever d- Molluscum contagiosum e- Measles f- Herpangina g- German measles ``` - A 10 year old girl presents with pinkish umblicated warty lesions on her buttocks - A 7 year old boy presents with high fever,sore throat ,enlarged painful cervical lymph nodes ,strawberry tongue and a diffuse erythematous rash - A 3 year old boy presents with fever and painful vesicles in his mouth - A seven year old boy presents with fever and intense erythema of the cheeks followed by spread of the rash to the trunk for only one day A 9 month infant presents with fever and wide spread macular rash. Tests were +ve for human herpes virus 6

Answer 29

- A 10 year old girl presents with pinkish umblicated warty lesions on her buttocks molluscum contagiosum - A 7 year old boy presents with high fever,sore throat ,enlarged painful cervical lymph nodes ,strawberry tongue and a diffuse erythematous rash Scarlet fever - GAS - A 3 year old boy presents with fever and painful vesicles in his mouth Herpangina - Coxsackie -A seven year old boy presents with fever and intense erythema of the cheeks followed by spread of the rash to the trunk for only one day erythema infectiosum A 9 month infant presents with fever and wide spread macular rash.tests were +ve for human herpes virus 6 Roseola infantum German measles also know as rubella Erythema infectiosum - also known as Parvovirus B19

Question 30

What are other names for these infections? German measles Erythema infectiosum Exanthem subitum

Answer 30

German measles - Rubella Erythema infectiosum - Parvo B19/ 5th disease Exanthem subitum - Roseola/ 6th disease

Question 31

Which of the following viruses are not associated with a vesicular rash - ``` Rubella Virus Measles Virus Parvovirus HSV-1 VZV ```

Answer 31

Rubella Virus Measles Virus Parvovirus

Question 32

A 19 year old man presents with flu-like illness, lymphadenopathy, fleeting macular rash and sore throat. History of unprotected sex over last 6 months. HIV testing positive. What is the most likely diagnosis?

Answer 32

Acute retroviral illness

Question 33

Farmer's wife presents with dark lesion/ purple nodule on finger. What are possible causes?

Answer 33

Orf - pox virus

Question 34

``` A. Dark lesion on farmer’s wife’s finger B. Umbilical lesions on boy’s face C. Lesion on fishmonger’s hand D. Hot-tub folliculitis E. Depigmentation of trunk and arms ``` 1. Malassezia furfur 2. Molloscum contagiosum 3. Orf 4. Pseudomonas aeruginosa 5. Erysipelothrix 6. Staph aureus

Answer 34

A. Dark lesion on farmer’s wife’s finger Orf B. Umbilical lesions on boy’s face Molluscum contagiosum C. Lesion on fishmonger’s hand Erysipelothrix D. Hot-tub folliculitis Pseudomonas E. Depigmentation of trunk and arms Malassezi furfur

Question 35

- Clostridium tetani - Corynebacterium diphtheriae - Clostridium botulinum - Staph aureus - Clostridium perfringens - Vibrio cholera 1. Produces elastase 2. Produces Lecithinase 3. Toxin production induces flaccid paralysis

Answer 35

1. Produces elastase Staph aureus 2. Produces Lecithinase Clostridium perfringens 3. Toxin production induces flaccid paralysis Clostridium botulinium

Question 36

Toxins ``` A. Shiga toxin B. SPE-C C. Diptheria toxin D. Cholera toxin E. Alpha toxin of Clostridium perfringes F. Tetanus toxin G. Endotoxin H. Botulinum toxin ``` 1. Its lipid component induces fever and shock by inducing TNF 2. Blocks release of acetylcholine 3. It inhibits protein synthesis by ADP-ribosylation of elongation factor 2 4. It increases cyclic AMP by ADP-ribosylation of G protein

Answer 36

1. Its lipid component induces fever and shock by inducing TNF Endotoxin - Lipid A 2. Blocks release of acetylcholine Botulinum toxin 3. It inhibits protein synthesis by ADP-ribosylation of elongation factor 2 Diptheria toxin 4. It increases cyclic AMP by ADP-ribosylation of G protein Cholera toxin?

Question 37

``` A. Shiga toxin B. SPE-C C. Diptheria toxin D. Cholera toxin E. Alpha toxin of Clostridium perfringens F. Tetanus toxin G. Endotoxin H. Botulinum toxin ``` 5. Action is via phospholipase C hydrolysis of phosphorylcholine in cell membrane 6. Inactivates protein synthesis by degrading 28s rRNA 7. Superantigen which binds directly to MHC II, and interacts with -chain of TCR to release cytokine cascade 8. A-B subunit toxin binds ganglioside receptors to interfere with synaptic transmission

Answer 37

5. Action is via phospholipase C hydrolysis of phosphorylcholine in cell membrane Alpha toxin of Clostridium perfringens 6. Inactivates protein synthesis by degrading 28s rRNA Shiga toxin 7. Superantigen which binds directly to MHC II, and interacts with -chain of TCR to release cytokine cascade SPE-C - Streptococcal Pyrogenic Exotoxin C is a super-antigen with wide cross-reactivity 8. A-B subunit toxin binds ganglioside receptors to interfere with synaptic transmission Tetanus toxin

Question 38

What are examples of polyoma viruses?

Answer 38

BK JC SV40

Question 39

Match the bacteria and their toxins ``` a-adenylate cyclase b-shiga like toxin c-cholera toxin d-oedema factor e-heat stable and heat labile toxin f-pyrogenic exotoxin ``` ``` E coli O157 pertussis ETEC Streptococcus pyogenes Bacillus anthracis ```

Answer 39

E coli O157 shiga like toxin pertussis adenylate cyclase ETEC heat stable and heat labile toxin Streptococcus pyogenes pyrogenic exotoxin - SPE Bacillus anthracis oedema factor

Question 40

i. Presence of P fimbriae ii. Presence of type 4 pili iii. Stimulation of T lymphocytes iv. Inhibits formation of phagolysosome v. Inhibition of acetylcholine receptors vi. Presynaptic inhibition of GABA receptors ``` A. Cystitis B. Toxic shock syndrome C. Tetanus D. Botulism E. Meningococcal carriage F. M TB ```

Answer 40

A. Cystitis P fimbriae - E. coli B. Toxic shock syndrome Stimulation of T lymphocytes C. Tetanus Presynaptic inhibition of GABA receptors D. Botulism Inhibition of acetylcholine receptors E. Meningococcal carriage Type 4 pili - assumed to play a key role in the initial adherence to human epithelial cells by virtue of the associated adhesin protein PilC F. M TB Inhibition of phagolysosome

Question 41

Toxins A. Increase in cAMP leading to fluid loss B. Includes lethal factor, oedema factor and protective antigen C. Elongation factor 2 D. Produces neurotoxin that leads to spastic paralysis E. Produces neurotoxin that leads to flaccid paralysis 1. C. diphtheria 2. C. botulinum 3. V. cholera 4. C. tetani 5. B. anthracis 6. B. pertussis 7. S.aureus

Answer 41

A. Increase in cAMP leading to fluid loss V cholera B. Includes lethal factor, oedema factor and protective antigen B anthracis C. Elongation factor 2 C diptheria D. Produces neurotoxin that leads to spastic paralysis C tetani E. Produces neurotoxin that leads to flaccid paralysis C botulinum

Question 42

What is the most important component of endotoxin leading to septic shock?

Answer 42

Lipid A

Question 43

Classifying streptococci What are examples of alpha haemolytic streptococci? How to differentiate them?

Answer 43

Strep pneumo - optochin S Strep viridans - optochin R

Question 44

Strep viridans group is wide group of bacteria, which live in oral cavity. Can cause IE/ neonatal sepsis/ gingivitis What are examples?

Answer 44

Strep milleri/ anginosus – abscesses brain/ liver/ GI S sanguinis S mutans S mitis

Question 45

Classifying streptococci beta haemolytic streptococci classified by Lancefield groups A/B/C/E, depending on carbohydrate expressed GAS and GBS are two of most important streptococci. GPC in chains seen on agar. How to rule out these two pathogens?

Answer 45

Latex agglutination of Lancefield groupings Strep pyogenes - bacitracin S, PYR pos Strep agalactiae - bacitracin R, PYR neg, CAMP pos, Hippurate hydrolysis pos

Question 46

What are GAS virulence factors?

Answer 46

``` GAS virulence factors M protein Lipoteichoic acid Hyaluronic acid Streptolysins Streptodrnase. DNA ```

Question 47

What are examples of gamma haemolytic streptococci? They cause UTI/ GI/ biliary/ IE infection

Answer 47

enterococci - AKA group D strep Strep bovis (gallolyticus)

Question 48

GPC in chains seen on blood agar. Gamma haemolytic. How to distinguish between these organisms? ``` enterococci - AKA group D strep Strep bovis (gallolyticus) ```

Answer 48

Bile esculin positive. Bile esculin agar contains oxgall (bile salts) to inhibit the growth of gram positive organisms other than enterococci and group D streptococci- confirms gamma haemolysis Enterococci - PYR pos Strep bovis - PYR neg

Question 49

What are uses for Hippurate hydrolysis test?

Answer 49

Tests for - GBS Campylobacter jejuni (coli is neg)

Question 50

Baby with early onset sepsis. Suspect GBS What is treatment?

Answer 50

Benzylpenicillin 7 days Lumbar puncture - if meningitis Benzylpenicillin 14 days, gentamicin 5 days

Question 51

48 AML 15 day chemo via Hickman line. Treated Taz + gent. Blood cultures grow GPC in long chains – alpha strep, optochin R What is possible causative organism? Does treatment need changed?

Answer 51

S viridans group – Strep oralis/ mitis Add vancomycin Source - either oral (mucositis) or line related Blood cultures from line/ consider remove line TTE

Question 52

48 trauma patient – base of skull fracture/ SAH/ IVH. Blood culture GPC in pairs and chains What are possible causative organisms

Answer 52

Alpha strep - Strep pneumoniae causing meningitis Gamma strep - Enterococcus Blood culture seems more likely to be streptococci than staphylocci. Possible other causes - Staph aureus Staph epidermidis