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