Microbiology of genital tract infections Flashcards

1
Q

what bacteria predominates in the healthy vagina? what does this produce?

A

Lactobacillus spp. predominate in the healthy vagina and produce:
-lactic acid +/- hydrogen peroxide (suppressing growth of other bacteria

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2
Q

What predisposes to vaginal thrush?

A
  • recent abiotic therapy
  • high estrogen levels
  • poorly controlled DM
  • immunocompromised pt
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3
Q

What is the presentation of vaginal thrush?

A
  • intensely itchy

- white cottage cheese like discharge

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4
Q

What is the diagnosis of vaginal thrush?

A
  • clinical

- high vaginal swab for culture - majority caused by c. albacans

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5
Q

What is the treatment of vaginal thrush?

A
  • oral fluconazole

- topical clotrimazole pessary/cream

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6
Q

How can thrush affect the penis?

A

-candida balanitis

=spotty appearance

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7
Q

What is the presentation of bacterial vaginosis?

A

-thin, watery, fishy-smelling vaginal discharge

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8
Q

What is the diagnosis of bacterial vaginosis?

A
  • clinically
  • raised pH >4.5
  • HVS sent to lab and examined microscopically for CLUE CELLS (but is highly innaccurate, hay-ison scoring system estimates the proportion of clue cells to epithelial/lactobacilli cells)
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9
Q

What is the treatment of bacterial vaginosis?

A

metronidazole orally

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10
Q

What is the classification of prostatis?

A

1: Acute bacterial prostatitis
2: Chronic bacterial prostatitis
3: Chronic prostatitis/chronic prostatitis pelvic pain syndrome

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11
Q

Acute bacterial prostatitis:

  • what are the symptoms
  • what can precede this
  • what organisms are causative
  • what has to be checked in men<35
  • what is the diagnosis?
  • what is the treatment?
A
  • Sx UTI +/- lower abdo/back/perineal/penile pain and tender prostate on examination
  • rare complication of UTI in men
  • same organisms as UTI (e.coli/coliforms/enterobacter sp)
  • check STI in men

diagnosis:
-clinical signs and MSSU for C+S +/- 1st pass urine for STI check

Treatment:
-ciprofloxacin for 28days or trimethoprim for 28d if risk c diff

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12
Q

What bacterial STIs exist?

A
  • chlamydia
  • gonorrhea
  • syphillis
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13
Q

Chlamydia trachomitis:

  • common
  • age incidence
  • what type of bacteria is this
A

Commonest STI in UK

  • 20-24yo
  • gram -ve obligate intracellular cocci with biphasic life cycle (no reprod. outside cells)
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14
Q

What can chlamydia infect? how is it transmitted?

A
  • urethra
  • rectum
  • throat
  • eyes
  • endocervix

Transmitted vaginally, orally, anally

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15
Q

How does chlamydia present in males and females?

A

70% females and 50% males are asymptomatic

Females:

  • PCB/IMB
  • lower abdo pain
  • dysparaunia
  • mucupurulent cervicitis

Males:

  • urethral discharge
  • dysuria
  • urethritis
  • epidymo orchitis
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16
Q

What different serology exists for chalmydia? what do they infect?

A

Serovars A-C: trachoma (eye infection)
Serovars D-K: genitals
Serovars L1-L3: lymphogranuloma venereum

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17
Q

What is the diagnosis for chlamydia?

A

test 14days post-exposure

NAAT (nucleic acid amplification test): females vulvovaginal swab, males first void urine

MSM: add rectal swab if receptive anal intercourse

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18
Q

What is the treatment of chlamydia?

A

Azithromycin 1g oral dose for uncomplicated

+ if MSM doxycycline 100mg BD for 1wk (gonorrhea)

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19
Q

What are the complications of chlamydia infection?

A
  • 9% PID risk (episode of PID increases risk ectopic pre. by 10X and carries risk tubal factor infertility of 15-20%)
  • tubal damage
  • chronic pelvic pain
  • transmission to neonate (17% conjunctivity/20% pneumonia)
  • conjunctivitis
  • SARA/reiters syndrome (commoner in men)
  • fitz-hugh-curtis syndrome
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20
Q

What type of bacteria is neisseria gonorrhea? what can it infect?

A
  • Gram -ve intracellular diplococcus (2 kidney beans facing eachother)
  • fastidious organism: only survives inside body in ideal conditions

infects urethra, rectum, throat, eyes, endocervix

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21
Q

What is the incubation period of neisseria gonorrhea? is it more easily passed from male to female or female to male?

A

incubation period of urethral infection in men 2-5days

Male to female 50-90% risk, female to male 20% risk

22
Q

What is the presentation of gonorrhea in males and females?

A

Females: up to 50% asymptomatic

  • 40% increased/altered/purulent vaginal discharge/dysuria
  • pelvic pain <5%
  • pharyngeal/rectal usually asymp

Males: asymptomatic 10% or less, urethral discharge >80%

  • dysuria
  • pharyngeal/rectal infection asymptomatic
23
Q

What is the diagnosis of gonorrhea?

A

Microscopy: urethral 90-95% sensitivity, endocervical 37-50% sensitivity

Culture: male urethra >95% sensitivity, female endocervix 80-92% sensitivity

NAATs: >96% sensitivity

24
Q

what is the management of gonorrhea?

A

1st line ceftriaxone 50mg IM

2nd line cefixime 400mg oral - if IM contraindicated/refused

cotreatment azithromycin 1g oral

-test of cure in all patients

25
Q

What are the complications of gonorrhea?

A

Lower genital tract:

  • bartholinitis
  • tysonitis
  • peri-urethral abscess
  • rectal abscess
  • epidydimitis
  • urethral stricture

Upper genital tract:

  • endometriosis
  • PID
  • hydrosalpinx
  • infertility
  • ectopic pregnancy
  • prostatis
26
Q
What are the pros and cons of:
-microscopy
-culture 
-NAAT
for gonorrhea?
A

Microscopy:

  • pros = near pt. diagnosis and timely rx
  • cons = invasive test, low sensitivity, requires confirmation

Culture:

  • pros = abiotic sensitivity and monitoring
  • cons = invasive test, requires specific media and incubation

NAAT:

  • pros = non-invasive, less problems with transport or media or storage, takes hrs (quick)
  • cons = risk of false +ves, + needs confirmation
27
Q

What kind of organism is syphillis?

A

spirochete organism: treponema pallidum (gram -ve)

28
Q

What is transmission of syphillis?

A
  • sexual
  • transplacental
  • birth
  • blood transfusion
  • healthcare workers

-it can be congenital or acquired

29
Q

Describe the stages of syphilis infection?

A

Primary lesion = organism multiplies at inoculation site and enters blood stream

  • chancre/painless ulcer that heals with no treatment (90% genital sites)
  • painless local lymphadenopathy
  • incubation period 9-90 days

Secondary stage = large no. of bacteria in blood with multi-manifestations at diff. sites

  • snail track mouth ulcers, generalised rash, flu-like symptoms
  • macular/follicular/pustular rash on palms and soles
  • mucous membrane lesions
  • generalised lymphadenopathy
  • patchy alopecia
  • condylomata lata (highly infectious lesion exuding serum teeming with organism)
  • incubation period is 6wks to 6mths

Latent stage = low-level multiplication of organism in intima of small blood vessels
-no symptoms

Late stage = cardiovascular/neurovascular complications

30
Q

What is the diagnosis of syphilis?

A
  • Dark ground microscopy to look for spirochetes in exudate (not done in tayside)
  • Swab primary/secondary lesions or infected lymph nodes for PCR
  • Serology: non-specific and specific abodies for t-pallidium in blood
31
Q

What different serological tests exist for syphillis - which is done in tayside?

A

Non-specific: VDRL/RPR (not Tayside)

  • indicate tissue inflammation = how active disease is
  • monitoring response to therapy = usually becomes -ve after treatment
  • may be falsely +ve in e.g. SLE, malaria, pregnancy

Specific: TPPA/TPHA (not Tayside)
-specific for syphillis but +ve for life

Screening test for syphillis: IgM/IgG Elisa on clotted blood sample (Tayside)

  • if this is -ve = result goes out -ve
  • if this is +ve further tests then performed on blood = IgM ELISA, VDRL test, TPPA test
32
Q

What is the treatment for syphillis?

A

Early syphillis:
-2.4MU benzathine penicillin X 1

Late syphillis:
-2.4MU benzathine penicillin X 3

Follow up: until RPR is -ve or serofast

  • titres should decrease 4 fold by 3-6mths in early
  • serological relapse/reinfection if titres increase 4 fold
33
Q

What causes genital warts?

A

HPV

  • commonest viral STI
  • lifetime risk is 80%
34
Q

Describe the HPV virus, which types infect anogenital epithelium? which are assoc. with cervical cancer?

A

> 170 types

  • 6 and 11 for anogenital warts
  • 16 and 18 for cervical cancer
35
Q

what is the transmission of HPV? what is the incubation period?

A
  • close skin to skin, likely from asymp. partner
  • incubation = 3wks - 9mths
  • subclinical disease in common on all anogenital sites
  • transmission of more than 1 HPV type is common
36
Q

What is the diagnosis and treatment of HPV?

A

Diagnosis: clinical (no test)

Treatment:

  • podophyllotoxin (warticon) - unlicensed use
  • imiquimod (aldera) - immune modifier for all anogenital warts

if dont work:

  • cryotherapy
  • electrocautery
37
Q

What is the prognosis of genital warts?

A

Warts often recur after treatment - immune system fights the infection

  • spontaneous clearance warts 20-34%
  • clearance with treatment 60%
  • persistance despite treatment 20% (smokers/immunosupressants)
38
Q

What strains does the vaccine for HPV contain? who gets it?

A

11-13yo girls, MSM up to age 45, HIV pts.

-6,11,16,18

39
Q

What causes genital herpes? what is this?

A

Herpes simplex virus type 1(HSV-1, cold sores) and type 2 (HSV-2, genital sores)
-enveloped virus containing double stranded DNA

40
Q

How is genital herpes transmitted?

A

Close contact with someone shedding virus - genital-genital or genital -oral

41
Q

Describe the pathogenesis of herpes simplex virus

A

Primary infection: asymptomatic or v. florid
-virus replicates in dermis/epidermis
-gets into nerve endings sensory/autonomic nerves
=inflamm. at nerve endings
=exquisitely painful multiple small vesicles, easily de-roofed

Then virus migrates to sacral root ganglion and ‘hides’ from immune system
-virus can reactivate from there = recurrent genital herpes attacks

Intermittant viral shedding can occur in absence of symptoms

42
Q

Primary herpes infection:

  • incubation time
  • duration
  • symptoms
A

Incubation time: 3-6 days

Duration: 4-21 days

Symptoms:

  • blistering and ulceration of genitalia
  • pain
  • dysuria externally
  • local lymphadenopathy
  • vaginal/urethral discharge
  • fever/myalgia prodrome
43
Q

Recurrent herpes infection:

  • what is this often misdiagnosed as?
  • what are the symptoms?
  • duration?
  • is this more common with HSV-1 or HSV-2?
A

Often misdiagnosed as thrush:

  • mild/localised anogenital tingling/burning/soreness
  • unilateral small blisters and ulcers
  • minimal systemic symptoms

Duration: 5-7days

More common with HSV-2

44
Q

What is the diagnosis of herpes infection?

A

Swab in virus transport medium of de-roofed blister for PCR, at base of blister (highly sensitive/highly specific)

45
Q

What is the treatment of herpes infection?

A

Acyclovir if early stage
Saline bathing
pain relief - topical lidocaine ointment

46
Q

if a lady is pregnant in the third trimester or 6wks from her EDD and she has a primary herpes simplex infection what is offered?

A

-planned C-section (if recurrence this isnt routinely offered)

47
Q

What is trichomonas vaginalis? how does this divide?

A

single cell protozoal parasite

-divides by binary fission and human hosts only

48
Q

How is trichomonas vaginalis transmitted? what is the presentation?

A

Transmission - sexual

Presentation:

  • vaginal discharge and irritation in females
  • urethritis in males
49
Q

What is the diagnosis and treatment for trichomonas vaginalis?

A

Diagnosis: high vaginal swab for microscopy

Treatment: oral metronidazol

50
Q

Pubic lice:

  • what causes this?
  • what is the presentation?
  • what is the treatment?
A

Caused by phthirus pubis from close genital skin contact

Presentation:

  • lice bite skin and feed on blood = itchy pubic area
  • female louse lays eggs on hair next to skin
  • males live for 22days, females for 17days

Treatment:
-malathion lotion

51
Q

What test is done for chlamydia and gonorrhea in the sexual health clinic/GP in practice? What other tests are available?

A

Combined NAAT or PCR test which tests both organisms in 1 test

  • highly specific and sensitive
  • 1st pass urine in males
  • HVS or vulvo-vaginal swab or endocervical swab during smear for females
  • rectal and throat swabs
  • eye swabs on babies

Microscopy of urethral/endocervical swabs in sexual health clinics:
-90+% specificity in males, less for females

Culture on selective agar plates: endocervical , rectal, throat swabs in sexual health clinics to check abiotic sensitivity and epidemiology

  • selective agar suppresses normal flora growth
  • if from GP organisms die on way to lab NAAT/PCR can be done even if they’re dead (that’s why have to wait 5 weeks for test of cure)