Microbiology of the GU tract

Question 1

What are the common bacterial STIs?

Answer 1

Chlamydia Trachomatis
Neisseria Gonorrhoeae
Mycoplasma Genitalium
Treponema Pallidum (syphilis)

Question 2

What are the common viruses that cause STIs?

Answer 2

HPV = genital warts
HSV = genital herpes
Hepatitis
HIV

Question 3

What parasites can cause STIs?

Answer 3

Trichomonas vaginalis
Phthirus pubis
Scabies

Question 4

What are the symptoms of goonocci in men?

Answer 4

Intense neutrophilic response that leads to a purulent discharge and pain with urination

Question 5

Why do you test lots of STIs at the same time?

Answer 5

Gonorrhoea and chlamydia together cause urethritis

Genital ulcers greatly increases the probability of HIV

Question 6

What organisms are part of the normal vaginal flora?

Answer 6

Lactobacillus predominate (this includes l. crispatus and l. jenseniii)
Group B beta-haemolytic streptococcus
Candida
Strep viridans

Question 7

What is the function of lactobacillus in the vagina?

Answer 7

Produce lactic acid +/- hydrogen peroxide

Question 8

What is the normal pH of the vagina?

Answer 8

4-4.5

Question 9

What is the gram stain of lactobacilli?

Answer 9

Gram positive bacilli

Question 10

What can be seen when looking at candida albicans down a microscope?

Answer 10

Branching
Hyphae
Yeast

Question 11

How many women are asymptomatically colonised with candida?

Answer 11

30%

Question 12

What is the commonest strain of candida?

Answer 12

Candida albicans

Question 13

What are predisposing factors for C.albicans infection?

Answer 13

Recent antibiotic therapy
High oestrogen levels (pregnancy, contraceptives)
Poorly controlled diabetes
Immunocompromised patients

Question 14

What is a buzz word for candida infection?

Answer 14

Cottage cheese

Question 15

How will candida present?

Answer 15

Intensely itchy white vaginal discharge

Question 16

How is candida diagnosed?

Answer 16

High vaginal swabs for culture

Question 17

What is the treatment for candida infection?

Answer 17

Topical clotrimazole pessary

Oral fluconazole

Question 18

How will candida affect men?

Answer 18

Spotty rash of candida balanitis

Question 19

What is the pathogenesis of gonorrhea infection?

Answer 19

Attaches to host epithelial cells and is endocytosed into cell to replicate within the host cell
Released into the subepithelial space
Typical urethral infections can result in prominent inflammation release of toxic fragments as well as release of chemotactic factors that attract neutrophilic leukocytes
Can cause asymptomatic genital infections

Question 20

GRAM STAIN OF GONORRHOEA (mooka said she examined)

Answer 20

Gram negative intracellular diplococcus

Question 21

Where will neisseria gonorrhoeae infect?

Answer 21

Urethra
Rectum
Throat
Endocervix
Eyes

Question 22

Is gonorrhoeae easy to grow?

Answer 22

No; fastidious organisms and will not survive well in less that ideal growth conditions

Question 23

How is N. gonorrhoeae diagnosed?

Answer 23

Microscopy of urethral/ endocervical swabs (done in SRH clinic)
Culture on selective agar plates

Question 24

Do you culture all swabs for gonorrhoea?

Answer 24

No; don’t culture high vaginal swabs

Question 25

Is a NAAT or a culture more effective?

Answer 25

NAAT has an increased sensitivity over culture | Gives you the ability to test urine specimens and self-obtained vaginal swabs

Question 26

What is the down side to NAAT?

Answer 26

Inability to perform antimicrobial susceptibility testing | Will detect dead organisms - so wait 5 weeks

Question 27

What is used to treat gonococcus?

Answer 27

Ceftriaxone | Azithromycin

Question 28

What is the commonest bacterial STI in the uk?

Answer 28

Chlamydia Trachomatis

Question 29

Can you gram stain chlamydia?

Answer 29

NO; no peptidoglycan in the cell wall, does not reproduce outside a host cell because it is a obligate intracellular bacteria with a biphasic life cycle

Question 30

What is the treatment for chlamydia?

Answer 30

Doxycycline 100mg bd x 7 days | or you can use azithromycin (1 g oral dose)

Question 31

What will serovars A-C chlamydia cause?

Answer 31

Eye infection

Question 32

What will serovars D-K chlamydia cause?`

Answer 32

Genital infection

Question 33

What will serovars L1-L3 chlamydia cause?

Answer 33

Lymphogranuloma venereum

Question 34

Who should you screen for Lymphogranuloma venereum?

Answer 34

Tropical areas | Men who have sex with men

Question 35

What will Lymphogranuloma venereum cause?

Answer 35

Histologically identical to crohn's; fissures, tenesmus, PR blood the LAST thing you give to these people is steroids and immunosuppressants - so if the criteria fits SCREEN FOR THIS

Question 36

How is NAAT used to diagnose chlamydia and gonorrhoea?

Answer 36

Male; first pass urine sample Female; HVS or vulvovaginal swab Rectal and throat swabs Eye swabs; if applicable

Question 37

What will trichomonas vaginalis cause?

Answer 37

Frothy, purulent discharge Irritation Urethritis in males

Question 38

Describe trichomonas vaginalis?

Answer 38

Single celled protozoal parasite Divides by binary fission (no cyst formation) - human host only Transmitted by sexual contact

Question 39

How is trichomonas vaginalis diagnosed?

Answer 39

High vaginal swab for microscopy (PCR test also available)

Question 40

What is the treatment for trichomonas vaginalis?

Answer 40

Oral metrondiazole

Question 41

Describe the symptoms of bacterial vaginosis?

Answer 41

Fishy smelling, thin homogeneous discharge of the vagina | May contain bubbles

Question 42

What is the positive "whiff" test?

Answer 42

Adding 10% potassium hydroxide to the discharge on the slide elicits an amine-like, fish odor

Question 43

What will a wet mount in bacterial vaginosis cause?

Answer 43

Absence of bacilli and their replacement with clumps of coccobacilli CLUE CELL

Question 44

What are the side effects to untreated bacterial vaginosis?

Answer 44

Increased rate of endometritis or salpingitis Premature rupture of membranes and preterm delivery Increased risk of acquisition of HIV

Question 45

What is the treatment for bacterial vaginosis?

Answer 45

Metronidazole for 7 days | Relapse rate is 30%

Question 46

Describe the appearance of treponema pallidum (syphilis)

Answer 46

Spirochaete organism Will not gram stain Will not grow in artificial culture media, so diagnosis relies on PCR test or on serological blood tests to detect antibodies

Question 47

What are the 4 stages to syphilis?

Answer 47

Chancre Secondary stage Latent stage Late stage

Question 48

Describe the chancre seen in syphilis

Answer 48

Organism multiplies at inoculation site and enters blood stream Will heal without treatment

Question 49

Describe the secondary stage of syphilis

Answer 49

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

Question 50

Describe the latent stage of syphilis

Answer 50

No symptoms Low level multiplication of spirochaete in intima of small blood vessels Can be divided into early latent and late latent

Question 51

What is late stage syphilis?

Answer 51

CV or neurovascular complications many years from initial infection

Question 52

How can syphilis be monitored?

Answer 52

VDRL RPR Monitors response to therapy

Question 53

How can syphilis be diagnosed?

Answer 53

History and examination Caveats; treatment history, reinfection risk, history, epidemiology Primary; dark ground microscopy, PCR, IgM Secondary; serology Tertiary; serology

Question 54

What is the treatment for syphilis?

Answer 54

Penicillin

Question 55

What is the basic screening for syphilis?

Answer 55

IgM and IgG screening test IF positive IgM ELISA (? acute), VDRL/ RPR (activity , TPPA (specific)

Question 56

What causes genital herpes?

Answer 56

HSV 1 and 2 Transmitted by close contact with someone shedding the virus Spread by genital/genital or oropharyngeal/genital contact

Question 57

Describe HSV

Answer 57

Enveloped virus containing double-stranded DNA

Question 58

What is the pathogenesis of HSV?

Answer 58

Primary infection can be asymptomatic OR florid Virus replicates in dermis and epidermis and enters nerve endings of sensory and autonomic nerves Inflammation at nerve endings results in exquisitely painful multiple small vesicles, which are early deroofed Virus migrates to sacral root ganglion and hides from the immune system Virus can reactivate from there causing recurrent genital herpes Intermittent virus shedding can occur in the absence of symptoms

Question 59

How can genital herpes be diagnosed?

Answer 59

Swab in virus transport medium of deroofed blister for PCR test; highly sensitive and specific Serology but not routinely used

Question 60

What is the treatment for genital herpes?

Answer 60

Aciclovir | Pain relief

Question 61

How are pubic lice acquired?

Answer 61

Close genital skin contact

Question 62

What is the pathogenesis of pubic lice?

Answer 62

Lice bite skin and feed on blood which causes itching in pubic area Female louse lay eggs on hair Males will live for 22 days and females for 17 days

Question 63

What is the treatment for pubic lice?

Answer 63

Malathion lotion