Microbiology of the Genital tract Flashcards Preview

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Flashcards in Microbiology of the Genital tract Deck (77):
1

What is the predominate bacteria in the normal vaginal flora and what does it do?

lactobacillus spp. - produces lactic acid and hydrogen peroxide to suppress the growth of other bacteria

2

What other organisms are present in the normal vaginal flora?

Strep viridans
Group B-haemolytic Strep
Candida spp.

3

Name 3 non-sexually transmitted genital tract infections

Candida (thrush)
Bacterial vaginosis (fishy smell)
prostatitis

4

What % of woman are colonised by Candida but show no symptoms of a thrush infection?

30%

5

What are predisposing factors for a candida infection?

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

6

What is the presentation of thrush?

Intensely itchy white vaginal discharge

7

How do you clinically diagnose thrush?

High vaginal swab for culture

8

What organism causes most cases of thrush?

Candida albicans

9

What is the treatment of Candida infections?

Topical clotrimazole pessary or cream
Oral fluconazole

10

What organisms can cause Bacterial vaginosis?

Gardnerella vaginalis
Mobiluncus sp.
Others include anaerobes

11

What are the predisposing factors of Bacterial vaginosis?

Uncertain

12

What are the symptoms of bacterial vaginosis?

Thin, watery, fishy smelling vaginal discharge

13

How do you diagnose bacterial vaginosis?

Raised vaginal pH >4.5

14

What is looked for in a laboratory sample of suspected bacterial vaginosis?

CLUE CELLS

15

What scoring system estimates the proportion of clue cells to epithelial cells and lactobacilli?

Hay-lyson scoring system

16

What is the treatment for bacterial vaginosis?

Metronidazole orally

17

What are the 3 classifications of Prostatitis?

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

18

What are the organisms involved with acute bacterial prostatitis?

Same as a UTI, E.coli and other coliforms, enterococcus sp.
Always check for STI's

19

What is acute bacterial prostatitis?

A rare complication of a UTI in men

20

What are the symptoms of acute bacterial prostatitis?

Symptoms of a UTI, may have lower abdo/back/perineal/penile pain
Tender prostate on examination

21

How is acute bacterial prostatitis diagnosed?

Clinical signs
MSSU for C&S
tests for STI's

22

What is the treatment for acute bacterial prostatitis?

Ciprofloxacin for 28 days
Trimethoprim for 28 days if high C.diff risk

23

Name 3 bacterial STI's

Chlamydia tachomatis
Neisseria gonorrhoeae
Treponema pallidum (Syphilis)

24

Name 3 viral STI's

Human papilloma virus (genital warts)
Herpes simplex virus (Genital herpes)
Hepatitis and HIV

25

Name 3 parasitic STI's

Trichomonas vaginalis
Phthirus pubis (Pubic lice/crabs)
Scabies

26

What parts of the body does Chlamydia effect?

urethra
rectum
throat
eyes
endocervix

27

Describe Chlamydia trachomatis

Obligate intracellular bacteria with biphasic life cycle - "energy parasite"

28

What colour does Chlamydia trachomatis stain with gram stain?

It doesn't, no peptidoglycan in the cell wall

29

What are the 3 serological groupingsof Chlamydia trachomatis?

Serovars A-C = Trachoma (eye infection) (no an STI)
Serovars D-K = Genital infection
Serovars L1-L3 = Lymphogranuloma venereum

30

What is the treatment for Chlamydia trachomatis?

Azithromycin (1g oral dose) for uncomplicated chlamydia

31

What is the infectious cysle of Chlamydia?

0hrs - attachment and entry
2-12hrs - Migration to perinuclear area and EB--> RB transition
12-24hrs - inclusion biogenesis and bacterial replication
24-48hrs - RB--> EB transition and cell lysis

32

Where does Neisseria gonorrhoeae effect?

Urethra
Rectum
Throat
Eyes
Endocervix

33

Describe Neisseria gonorrhoeae

Gram -ve diplococcus
Like two kidney beans facing each other
Easily ohagocytosed by polymorphs, so often appear intracellularly on a gram film

34

What does the term 'Fastidious organism' mean?

does not survive well in less than ideal growth conditions
i.e. outside the body

35

How can you diagnose both chlamydia and gonorrhoea?

Combined nucleic acid amplification tests (NAATs) or polymerase chain reaction test (PCR)
tests for both organisms in 1 test

36

What other tests are available for Neisseria gonorrhoeae?

Microscopy of urethral / endocervical swabs
Culture on selected agar plate

37

What are some advantages for PCR/NAATs over culture?

Less invasive specimens required
More sensitive than cultures
+ve even if organism has died in transit to the lab
Takes hours, not days

38

What are disadvantages of PCR/NAATs over culture?

Cannot test antibiotic sensitivities without culture, so difficult to track resistance
Will detect dead organism (have to wait 5 weeks to do "test of cure" tests

39

What is the recommended treatment for Neisseria gonorrhoeae?

Intramuscular ceftriaxone + oral azithromycin

40

What organism causes Syphilis?

the spirochaete organism that is Treponema pallidum

41

What colour does Treponema pallidum gram stain?

It doesn't

42

How do you test for Treponema pallidum?

PCR or serology tests for antibodies. No culture as it can't be grown in artificial culture media

43

Describe the 1st stage of syphilis

1 y lesion (chancre) - organism multiplies at inoculation site and gets into bloodstream. Chancre will heal without treatment

44

Describe the second stage of syphilis

2y stage - large nos. bacteria circulating in blood with multiple manifestations at different sites (snail-track mouth ulcers, generalised rash, flu-like symptoms)

45

Describe the 3rd stage of syphilis

Latent stage - no symptoms, but low-level multiplication of spirochaete in intima of small blood vessels. Can be divided into early latent and late latent periods

46

Describe the 4th stage of syphilis?

Late stage - cardiovascular or neurovascular complications many years later

47

How do you diagnose syphilis?

Dark ground microscopy to look for lesions for spirochaetes in exudate from 1y to 2y lesions
Swab of 1y and 2y lesions for PCR
Serology for specific and non-specific antibodies to Treponema pallidum

48

What are the non-specific tests for Treponema pallidum for?

Tests indicate how active the disease is and are useful to monitor the response to treatment

49

What are the specific tests for Treponema pallidum for?

Confirm the diagnosis, but antibody levels decrease very slowly even after successful treatment, ad often remain for life

50

When may non-specific tests for Treponema pallidum give a false positive?

SLE
Malaria
Pregnancy

51

What are specific serological tests for Treponema pallidum?

TPPA - Treponema pallidum particle agglutination assay
TPHA - Treponema pallidum haemagglutination assay

52

What two antibodies are looked for in the ELISA screening test for syphilis?

IgG and IgM

53

What is Treponema pallidum very sensitive to?

Penicillin

54

What are genital warts?

Non-enveloped icosohedral virus containing double stranded DNA

55

What strands of HPV cause genital warts?

6 and 11

56

What strands of HPV cause cervical cancer?

16 and 18

57

What is the diagnosis of genital warts?

Mainly clinical

58

What is the treatment for genital warts?

Cryotherapy
Podophyllotoxin
Cream/lotion

59

What age group is the quadrivalent vaccine given to?

11-13 year olds girls

60

What does the quadrivalent vaccine protect against?

HPV type 6,11,16 and 18

61

Describe genital herpes?

Enveloped virus containing double stranded DNA

62

What causes genital herpes?

HSV-1
HSV-2

63

How may the primary infection present?

Asymptomatic or very florid

64

Where does the virus in genital herpes replicate?

In the dermis and epidermis

65

Where do genital herpes viruses get into?

Into the nerve endings of sensory and autonomic nerves
Causes inflammation, exquisitely painful, multiple small vesicles which are easily deroofed

66

Where does the virus in genital herpes migrate to?

The sacral root ganglion and "hides" from the immune system

67

How is genital herpes diagnosed?

Swab for virus transport medium of deroofed blister for PCR testing

68

What is the treatment for genital herpes?

Aciclovir helpful if taken early
Pain relief

69

Are the vaccines for genital herpes?

Yes, but they have been dissapointing

70

What is Trichomonas vaginalis?

Single celled protozoal parasite.
divides by binary fission (no cyst form is known) and it's only host is human

71

What does Trichomonas vaginalis?

Vaginal discharge and irritation in females (and urethritis in males

72

How do you diagnose Trichomonas vaginalis?

High vaginal swab for microscopy PCR

73

What is the treatment for Trichomonas vaginalis?

Oral metronidazole

74

What is Phthirus pubis?

Pubic lice
Lice bite skin and feed on blod, which causes itching in pubic area

75

How do pubic lice replicate?

Female louse lays eggs on hair next to skin

76

How long do pubic lice live for?

Males for 22 days, females for 17 days

77

What is the treatment for pubic lice?

malathion lotion