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Flashcards in Microbiology Deck (65):
1

What bacterial species predominates in healthy vaginal flora?

Lactobacillus spp.

2

What does Lactobacillus spp. produce and what is the effect of these products?

Lactic acid +/- hydrogen peroxide
Suppresses growth of other bacteria

3

List some bacteria other than Lactobacillus spp. that can be part of the normal vaginal flora

Strep viridans
Group B Strep
Candida spp. (small numbers)

4

What are the 3 main non-sexually-transmitted genital tract infections?

Vaginal thrush
Bacterial vaginosis
Prostatitis

5

Which bacteria causes vaginal thrush?

Candida (usually albicans)

6

The presence of Candida on vaginal swab indicates vaginal thrush. True/False?

False
30% of females are colonised by small numbers of Candida as part of normal flora

7

List some predisposing factors to developing Candida infection

Recent antibiotic therapy
High oestrogen levels (pregnant, contraceptives)
Poorly controlled diabetes
Severely immunocompromised

8

Describe clinical presentation of vaginal thrush

Intensely itchy
White vaginal discharge "like cottage cheese"

9

How is the diagnosis of vaginal thrush made?

Clinical diagnosis/appearance
Vaginal swab to culture for C. albicans

10

How is vaginal thrush treated?

Topical clotrimazole
Oral fluconazole if no response

11

What is characteristic of Candida albicans on gram film?

Appearance of budding

12

Who typically gets other forms of Candida infection (other than albicans)?

Poorly controlled diabetics (C. balanitis)
Immunosuppressed

13

Which organisms are the main causes of bacterial vaginosis?

Gardnerella vaginalis
Mobiluncus sp.
Other anaerobes

14

Describe clinical presentation of bacterial vaginosis

Thin, watery, fish-smelling discharge that reeeeaally stinks

15

How is a diagnosis of bacterial vaginosis made?

Clinical diagnosis/examination
Raised vaginal pH greater than 4.5

16

The presence of what cells on microscopy suggest bacterial vaginosis?

Clue cells

17

How is bacterial vaginosis treated?

Oral metronidazole

18

Describe the clinical presentation of acute bacterial prostatitis

UTI-like
Abdominal/back/perineal/penile pain
Tender prostate

19

A mid-stream sample of urine is required to test for urethral infection in acute bacterial prostatitis. True/False?

False
Mid-stream for upper UTI, first-pass for lower UTI

20

How is acute bacterial prostatitis treated?

Ciprofloxacin for 28 days
Trimethoprim if high C. diff risk

21

List the 3 main sexually-transmitted bacterial infections

Chlamydia
Gonorrhoea
Syphilis

22

What is the commonest bacterial STI in the UK? What organism causes it?

Chlamydia, caused by Chlamydia trachomatis

23

What areas of the body can chlamydia infect?

Eyes
Throat
Rectum
Urethra
Cervix

24

Chlamydia reproduces both in and out -side the host cell. True/False?

False
Obligate bacteria that only reproduces inside the host

25

Does chlamydia stain with Gram stain?

No because no peptidoglycan in cell wall

26

What are the 3 serological groupings of chlamydia and their respective infections?

Serovars A-C = trachoma/eye infection
Serovars D-K = genital infection
Serovars L1-L3 = lymphogranuloma venereum

27

What condition does lymphogranuloma venereum mimic on presentation?

Inflammatory bowel disease - features of proptosis, PR bleed, irritation, fullness

28

How is chlamydia infection treated?

Azithromycin if uncomplicated
Doxycycline for 7 days
3 weeks if LGV

29

Which bacteria causes gonorrhoea?

Neisseria gonorrhoeae

30

Gonorrhoea is more common than chlamydia. True/False?

False

31

Describe the appearance of Neisseria gonorrhoeae on gram stain

Gram -ve
Diplococcus

32

Neisseria gonorrhoea is a fastidious organism. What does this mean?

Doesn't grow well in less than ideal conditions i.e. outside the body

33

What is the typical clinical appearance of gonorrhoea?

Purulent discharge

34

How are both chlamyida and gonorrhoea diagnosed?

Nucleic acid amplification test
PCR
Microscopy of swabs
Specific agar culture (gonorrhoea only)

35

What are the advantages of NAAT/PCR over culture?

Quick
Less invasive
More sensitive

36

What are the disadvantages of NAAT/PCR over culture?

Will detect dead organisms so have to wait 5 weeks before retest
Cannot detect antibiotic sensitivity

37

Many strains of gonorrhoea are now antibiotic resistant. True/False?

True

38

What is the recommended treatment for gonorrhoea?

Ceftriaxone + azithromycin

39

Which bacteria causes syphilis?

Treponema pallidum

40

Treponema pallidum does not stain with gram stain. True/False?

True

41

Treponema pallidum cannot be grown in culture. True/False?

True

42

How does stage 1 syphilis present?

Chancre (painless ulcer)

43

How does stage 2 syphilis present?

Flu-like symptoms
Ulcers
Generalised rash, palms and soles affected

44

How does latent stage (stage 3) syphilis present?

No symptoms

45

How does late-stage (stage 4) syphilis present?

Cardiovascular (aortic aneurysm)
Neurovascular (high-stump gait)

46

Syphilis is not infectious in the latent period. True/False?

True

47

What method is used to diagnose syphilis?

PCR

48

How is serology testing for syphilis done?

Test for non-specific and specific antibodies to T. pallidum in blood

49

What is the main non-serological test done for syphilis? When is it useful?

Rapid plasma regain
Useful for monitoring response to therapy

50

List the main specific serological tests done for syphilis

TPPA
TPHA
IgM + IgG ELISA (screening test)

51

What is the gold-standard treatment for syphilis?

Penicillin injection

52

What are the 3 main sexually-transmitted viral infections?

Genital warts
Genital herpes
Hepatitis and HIV

53

What is the commonest viral STI and its cause?

Genital warts, caused by human papilloma virus

54

What subtypes of HPV are the most common causes of genital warts?

6 + 11

55

What subtypes of HPV are associated with increased risk of cervical cancer?

16 + 18

56

How is genital warts diagnosed?

Clinical diagnosis as no lab test

57

How are genital warts treated?

DESTRUCTION via
cryotherapy/toxic cream
Vaccination given to 11-13 year old girls

58

What virus causes genital herpes?

Herpes simplex virus types 1 &2

59

How is genital herpes diagnosed?

Swab for PCR

60

How is genital herpes treated?

Aciclovir
Pain relief

61

What is the most common sexually-transmitted parasitic disease?

Trichomonas vaginalis

62

How is Trichomonas vaginalis diagnosed?

Vaginal swab for microscopy

63

How is Trichomonas vaginalis treated?

Oral metronidazole

64

Which parasite causes pubic lice?

Phthirus pubis

65

How are pubic lice treated?

Malathion lotion