Microbiology

Question 1

what organisms make up normal vaginal flora

Answer 1

Lactobacillus spp. [predominate]

Strep Viridans
Group B beta-haemolytic Strep
Candida spp

Question 2

why is Lactobacillus spp. important for the vagina flora

Answer 2

produced lactic acid +/- hydrogen peroxide

which suppress growth of other bacteria

Question 3

what does it mean by beta-haemolytic

Answer 3

complete clear zone around it

Question 4

what are the non-sexually transmitted genital tract infections

Answer 4

Candida infection (“vaginal thrush”)
Bacterial vaginosis

Prostatitis

Question 5

what are predisposing factors for a candida infection

Answer 5

Recent antibiotic therapy

High oestrogen levels (pregnancy, certain types of contraceptives)

Poorly controlled diabetes

Immunocompromised patients (severely immunocompromised)

Question 6

what is the Sx of candida infection

Answer 6

intensely itch white vaginal discharge
- “cottage cheese”

spotty rash - just in C. balanitis

Question 7

diagnosis of candida infection

Answer 7

Clinical diagnosis

High Vaginal Swab [HVS] for culture

Question 8

Tx for candida infection

Answer 8

1st line - Topical Clotrimazole 500mg 2-3 times daily

2nd line - Oral Fluconazole 150mg as a single dose + Topical Clotrimazole

Question 9

what is the appearance of c. albicans

Answer 9

yeasts structure with budding

Question 10

what is the Sx of bacterial vaginosis

Answer 10

thin, watery, fishy-smelling vaginal discharge

Question 11

Ix of bacterial vaginosis

Answer 11

clinical diagnosis
raised vaginal pH (pH > 4.5)
HVS = looking for presence of clue cells

Question 12

Tx of bacterial vaginosis

Answer 12

Metronidazole 500mg twice daily

Question 13

what is the classification of prostatitis

Answer 13

1. Acute bacterial prostatitis
2. Chronic bacterial prostatitis
3. Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS)

Question 14

Sx of acute bacterial prostatitis

Answer 14

Sx of UTI [dysuria, frequency, nocturia, haematuria]

lower abdomen pain, back/perineal/penile pain,

tender prostate O/E

Question 15

what organism is responsible for acute bacterial prostatitis

Answer 15

E.Coli

- same as UTI

Question 16

if a patient has acute bacterial prostatitis, what else should they be tested for

Answer 16

STI in patients < 35y/o: Gonorrhoea, chlamydia

Question 17

Ix for acute bacterial prostatitis

Answer 17

Clinical signs + MSSU for C&S

First pass urine for STI tests

Question 18

Tx for acute bacterial prostatitis

Answer 18

1st line = Ciprofloxacin for 28 days

2nd line = Trimethoprim for 28 days if high C. Diff risk

Question 19

what is the commonest bacterial STI in the UK

Answer 19

Chlamydia trachomatis

Question 20

what can chlamydia affect

Answer 20

urethra, rectum, throat and eyes

Question 21

how does chlamydia strain with gram stain

Answer 21

NO stain

- no peptidoglycan in the cell wall

Question 22

what are the 3 serological groupings of chlamydia

Answer 22

Serovars A-C = Trachoma (eye infection) (NOT an STI)
Serovars D-K = Genital infection
Serovars L1-L3 = Lymphogranuloma venereum

Question 23

Tx of chlamydia

Answer 23

Azithomycin (1g oral dose) for uncomplicated chlamidia

Doxycycline 100mg bd x 7 days

Question 24

what is Lymphogranuloma venereum

Answer 24

inflammation of the rectum

- can mimic crohns disease as people think they need to go to the toilet

Question 25

what does neisseria gonorrhoea affect

Answer 25

urethra, rectum, throat, eyes, endocervix

Question 26

how does neisseria gonorrhoea appear on gram staining

Answer 26

Gram negative diplococcus | - Look like “2 kidney beans facing each other”

Question 27

Ix of chylamydia and gonorrhoea

Answer 27

NAAT or PCR - tests for both For males, need first pass urine sample For females, HVS or vulvo-vaginal swab (VVS)

Question 28

what is the advantages of PCR/NAAT over culture

Answer 28

less invasive more sensitive takes hours for result [not days]

Question 29

what is the disadvantages of PCR/NAAT over culture

Answer 29

Cannot test antibiotic sensitivities without culture, so difficult to track antibiotic resistance Will detect dead organisms

Question 30

how long do you have to wait to do a test of cure

Answer 30

5 weeks

Question 31

Tx of gonorrhoea

Answer 31

IM ceftriaxone + oral azithromycin

Question 32

what causes syphilis

Answer 32

Treponema pallidum

Question 33

how does Treponema pallidum stain

Answer 33

does not stain with gram stain

Question 34

what are the 4 stages of syphilis

Answer 34

1y lesion (chancre) 2y stage Latent stage Late stage

Question 35

what is 1y lesion stage

Answer 35

organism multiplies at inoculation site and gets into bloodstream. Chancre will heal without treatment

Question 36

what is 2y lesion stage

Answer 36

large nos. bacteria circulating in blood with multiple manifestations at different sites (“snail-track” mouth ulcers, generalised rash, flu-like symptoms etc.)

Question 37

what is the latent stage

Answer 37

no symptoms, but low-level multiplication of spirochaete in intima of small blood vessels. Can be divided into early latent and late latent periods. Not infectious in the latent stage.

Question 38

what is late stage syphilis

Answer 38

cardiovascular or neurovascular complications many years later

Question 39

Ix of syphilis

Answer 39

1 - Swab of 1y or 2y lesions for PCR 2 - Serology – tests for non-specific and specific antibodies to T. pallidum in blood

Question 40

what are the two type of tests done in serology of syphilis

Answer 40

non specific - indicates how active the disease is - useful to monitor the response to treatment specific - confirm diagnosis

Question 41

1st line test for syphilis

Answer 41

IgM & IgG ELISA

Question 42

2nd line test for syphilis if 1st line positive

Answer 42

IgM ELISA VDRL test TPPA test

Question 43

Tx for syphilis

Answer 43

2.4 IM Benzathine penicillin x1 if penicillin allergic - Doxycyline 100mg oral + Prednisolone 40-60mg

Question 44

what is the commonest viral STI

Answer 44

genital warts

Question 45

what causes genital warts

Answer 45

HPV

Question 46

what types of HPV are associated with pathology

Answer 46

6 & 11 = genital warts 16 & 18 = risk of cervical cancer

Question 47

how is genital warts spread

Answer 47

by close genital skin contact

Question 48

diagnosis of genital warts

Answer 48

clinical

Question 49

Tx for genital warts

Answer 49

cryotherapy; podophyllotoxin cream/lotion

Question 50

what vaccine is given for HPV

Answer 50

quadrivalent vaccine give to 11-13 year old girls immunises against types 6,11,16 & 18

Question 51

how do genital warts appear

Answer 51

whiter than the surrounding skin with a rough surface

Question 52

what causes genital herpes

Answer 52

HSV type 1 and type 2 | HSV-1 and HSV-2

Question 53

what is HSV-1 also associated with

Answer 53

cold sores

Question 54

how are genital herpes spread

Answer 54

genital/genital or oropharyngeal/genital contact

Question 55

what is the pathogenesis of genital herpes

Answer 55

Primary infection may be asymptomatic (or very florid) Virus replicates in dermis and epidermis Gets into nerve endings of sensory and autonomic nerves Inflammation at nerve endings Virus migrates to sacral root ganglion and “hides” from the immune system there Virus can reactivate from there causing recurrent genital herpes attacks

Question 56

presentation of genital herpes

Answer 56

exquisitely painful multiple small vesicles, which are easily deroofed

Question 57

Ix for genital herpes

Answer 57

Swab deroofed blister for PCR test

Question 58

Tx for genital herpes

Answer 58

pain relief | aciclovir may help if taken early enough

Question 59

what is Trichomonas vaginalis

Answer 59

single celled protozoal parasite

Question 60

Sx of Trichomonas vaginalis

Answer 60

vaginal discharge irritation urethritis in males

Question 61

Ix and Tx of Trichomonas vaginalis

Answer 61

HVS for microscopy Oral metronidazole

Question 62

what is Tx for lice

Answer 62

malathion lotion