Microbiology of GU tract & STIs

Question 1

List microorganisms that cause STIs

Answer 1

Bacteria: Chlamydia trachomatis, neisseria gonorrhoea, mycoplasma genitalium, treponema pallidum
Viral: HSV, HPV, HIV
Parasites: trichonomas vaginalis, phthirus pubis, scabies

Question 2

Can you become immune after having an STI

Answer 2

NO, reinfection becomes more common

Question 3

STIs travel in groups, true or false

Answer 3

TRUE, test for one test for all

Question 4

What is the predominant microorganism in normal vaginal flora

Answer 4

Lactobacillus - Gm +ve bacilli

Question 5

What other microorganisms may or may not be present in normal vaginal flora

Answer 5

Group B strep
Candida
Strep viridans group

Question 6

What is vaginal thrush/candidiasis caused by

Answer 6

Candida albicans fungus

Question 7

Is vaginal thrush an STI

Answer 7

NO

Question 8

What are predisposing factors to developing vaginal thrush

Answer 8

Recent antibiotic therapy
Poorly controlled diabetes mellitus
High oestrogen levels - some contraceptives
Immunocompromised patients

Question 9

What are features of vaginal thrush

Answer 9

Intensely white itchy discharge

Diagnosed clinically or with a high vaginal swab

Question 10

Treatment of vaginal thrush

Answer 10

Topical clotrimazole cream

PO fluconazole

Question 11

Can you get candida albicans infection in males

Answer 11

Yes, as candida balanitis

It is far less common

Question 12

What causes gonorrhoea

Answer 12

Neisseria Gonorrhoea = Gm -ve intracellular diplococcus

Question 13

Which is less common, chlamydia or gonorrhoea

Answer 13

Gonorrhoea

Question 14

Where can gonorrhoea infect

Answer 14

Urethra, endocervix, rectum, throat, eyes

Question 15

What discharge occurs in gonorrhoea

Answer 15

PURULENT (pus) discharge

Question 16

Neisseria gonorrhoea is a fastidious organism, what does this mean

Answer 16

Fastidious = dies easily if not in ideal conditions

Question 17

what tests can look for gonorrhoea

Answer 17

Microscopy –> Gm- intracellular diplococci
Culture –> allows determination of antibiotic sensitivities
Nucleic Acid Amplification Test (NAAT) –> picks up genetic material

Question 18

What is the treatment of gonorrhoea

Answer 18

IM ceftriaxone 1g

Question 19

What samples are used for NAAT

Answer 19

Males - 1st void urine sample

Females - self taken vaginal swab

Question 20

What causes Chlamydia

Answer 20

Chlamydia trachomatis = behaves like a gram negative
HAS NO GRAM STAIN
because of no peptidoglycan wall

Question 21

Chlamydia is the most common STI in the UK, true or false

Answer 21

TRUE

Question 22

Chlamydia is an obligate intracellular bacteria, what does this mean

Answer 22

It only grows inside the cell, cannot grow outside of the cell

Question 23

Where can chlamydia infect

Answer 23

urethra, rectum, endocervix, throat, eyes

Question 24

what are the serological groupings of chlamydia

Answer 24

Serovars A-C: trachoma eye infection
Seovars D-K: genital infection
Serovars L1-3: lymphogranuolma venereum (LGV)

Question 25

What is LGV and what condition can it mimic

Answer 25

Lymphogranuloma venereum is a tropical disease common in MSM It is clinically similar to Crohns disease

Question 26

What is the treatment of Chlamydia

Answer 26

1st - PO doxycycline 2nd - PO azithromycin 3rd - PO erythromycin

Question 27

How do you test for Chlamydia

Answer 27

NAAT - can test for at the same time as gonorrhoea

Question 28

What are the disadvantages of NAAT

Answer 28

Cannot perform antimicrobial susceptibility testing | high risk of false positives in gonorrhoea

Question 29

What is trichonomas vaginalis / trichomoniasis and what is its management

Answer 29

A trophozoite parasite Presents with vaginal discharge and irritation / urethritis Tx: PO metronidazole

Question 30

What is bacterial vaginosis (BV)

Answer 30

Disturbance in the normal vaginal flora | Not caused by just 1 bug

Question 31

Is BV an STI

Answer 31

No, but it can co-exist with STIs

Question 32

What does BV present with

Answer 32

Fishy smelling thin homogenous vaginal discharge, may contain bubbles

Question 33

Describe features of BV

Answer 33

+ve Whiff test from volatile amines Absence of lactobacilli and presence of coccobacilli clumps as their replacement Clue cells = vaginal epithelial cells coated with coccobacilli clumps

Question 34

What are the 3 main features of BV

Answer 34

disturbed microbiome loss of vaginal acidity normal cellular protection has changed

Question 35

Treatment of BV

Answer 35

PO metronidazole 7 days NB - high relapse rate No benefit in treating male sexual partner

Question 36

What causes syphilis

Answer 36

Treponema pallidum | NO GRAM STAIN

Question 37

Treponema pallidum can be cultured, true or false

Answer 37

FALSE, treponema pallidum cannot be cultured

Question 38

How do you test for syphilis

Answer 38

``` Dark ground microscopy PCR serological testing IgM VDLR / RPR ```

Question 39

What are the 4 stages of syphilis

Answer 39

Primary - chancre Secondary - can manifest in anyway Latent - no symptoms, but continues to grow Tertiary - CVS or neurosyphilis

Question 40

What are VDRL and RPR useful for

Answer 40

Useful for monitoring the disease response to therapy and can be used to see whether disease has been cured

Question 41

Which antibiotic is syphilis very sensitive to

Answer 41

Penicillin Tx: IM long lasting penicillin preparations Anything else is inferior Would even consider desensitising if patient is penicillin allergic

Question 42

What causes genital herpes

Answer 42

Herpes simplex 1 + 2 | virus containing double stranded DNA

Question 43

Symptoms of genital herpes

Answer 43

painful multiple small vesicles that are easily deroofed

Question 44

what is the test for genital herpes

Answer 44

viral swab of deroofed blister for PCR

Question 45

Management of genital herpes

Answer 45

Aciclovir and pain killers

Question 46

what is the incubation period of chlamydia

Answer 46

14 days

Question 47

what is Fitz-Hugh-Curtis syndrome

Answer 47

perihepatitis associated with PID

Question 48

what is the incubation period of gonorrhoea

Answer 48

2-5 days

Question 49

how long do you wait to do the test of cure in gonorrhoea

Answer 49

2 weeks from site where they had a positive swab

Question 50

in genital herpes, what is meant by primary infection

Answer 50

never been exposed to herpes before

Question 51

in genital herpes, what is meant by non-primary first episode

Answer 51

been exposed before, but this is the first symptomatic presentation

Question 52

what is the incubation period for primary infection of HSV

Answer 52

3-6 days

Question 53

which has a better prognosis, HSV 1 or 2

Answer 53

HSV 1

Question 54

what is the most common viral STI in the UK

Answer 54

HPV

Question 55

what do HPV 1+2 cause

Answer 55

warts on hands and feet

Question 56

What do HPV 6+11 cause

Answer 56

genital warts

Question 57

what do HPV 16+18 cause

Answer 57

cervical cancer

Question 58

what is the incubation of HPV

Answer 58

3 weeks to 9 months

Question 59

what is the management of genital warts

Answer 59

podopyhyllotoxin imiquimod cryotherapy

Question 60

what is the appearance of treponema pallidum

Answer 60

spirochete

Question 61

what is the incubation period of primary syphilis

Answer 61

9-90 days

Question 62

what is a chancre

Answer 62

painless ulceration at site of inoculation

Question 63

what is the incubation period of secondary syphilis

Answer 63

6 weeks - 6 months