Sexually Transmitted Bacterial Infections Flashcards

1
Q

How many cases of STIs are seen a year?

A

333 million new cases p.a.

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2
Q

What age are the majority of individuals who have STIs?

A

<25 years old

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3
Q

How are STIs transmitted primarily?

A

Genital, oral/genital, anal/genital contact

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4
Q

What do STIs usually lead to?

A

Preventable infertility

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5
Q

Why are STIs increasing and becoming more difficult to control?

A

Increasing density and mobility of populations
Difficulty in changing human sexual behaviour
General level of promiscuity and tendency for increased number of sexual partners
Absence of vaccines for almost all STIs
Belief that most STIs are treatable

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6
Q

What are the top bacteria STIs?

A

Neisseria gonorrhoeae- gonorrhoea
Chlamydia trachomatis- non-specific urethritis
Treponema pallidum- syphilis
Haemophilus dureyi- chancroid

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7
Q

What are the top virus STIs?

A

Papillomaviruses- genital warts etc.
Herpes simplex- genital herpes
HIV- AIDS
Hepatitis B- hepatitis

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8
Q

What are the top fungi STIs?

A

Candida albicans- vaginal thrush

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9
Q

What are the top protozoa STIs?

A

Trichomonas vaginalis- vaginitis, urethritis

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10
Q

What bacterium cause gonorrhoea?

A

Neisseria gonorrhoeae

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11
Q

What is the structure of neisseria gonorrhoeae?

A

Non-motile, gram-negative diplococcus

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12
Q

Where is neisseria gonorrhoeae carried?

A

Genital tract
Nasopharynx
Anus

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13
Q

How many new cases are there of gonorrhoea a year?

A

62 million

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14
Q

What are the chances of getting gonorrhoea after a single encounter with an infected partner?

A

Female 50%

Male 20%

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15
Q

What are the symptoms of gonorrhoea?

A

Males- urethritis, purulent discharge and dysuria (painful urination)
Females- initial urethritis or cervicitis, often mild, spread to uterus (endometritis), oviducts (salpingitis) and pelvic inflammatory disease

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16
Q

What percentage of males and females have asymptomatic for gonorrhoea?

A

80% females

10% males

17
Q

What are the stages of pathogenesis for gonorrhoea?

A
Entry and Adhesion
o	Following entry, bacteria attach to the columnar epithelium via pili
Non-piliatd strains are non-infective
Rapidly multiply
o	Some localised, others become systemic
Invades epithelial cells and multiplies within vacuoles, protected from antibodies and phagocytes
IgA protease
Resist Serum killing by complement
18
Q

What is the antigenic variation?

A

Capacity to genetically change surface structures

19
Q

What is Pili and outer-membrane proteins (POMPS)?

A

For adhesion to mucosal epithelium have hypervariable regions and undergo frequent alteration

20
Q

What are the vaccines for gonorrhoea?

A

None available

21
Q

What is the treatment for gonorrhoea?

A

Single injection of high dose antibiotic (extended spectrum penicillin)
Rapidly becoming untreatable

22
Q

What is chlamydia?

A
Very small bacteria
o	Obligate intracellular parasites
o	Unique life cycle
o	STI associated Chlamydia trachomatis
Small genome 1 x 106 kb (1/4 that of E. coli)
23
Q

What bacterium causes chlamydia?

A

Chlamydia trachomatis

24
Q

What are the symptoms of chlamydia?

A

Many infections are asymptomatic

25
Q

What is the pathogenesis in women for chlamydia?

A

Cervical infection
Increased susceptibility to HIV
Infection of infant
Fallopian tube- PID, Ectopic pregnancy, infertility

26
Q

What is the pathogenesis in men for chlamydia?

A

Urethral infection leads to painful urination; discharge and reactive arthritis

27
Q

What is damage in chlaymdia due to?

A

Direct destruction of cells
Host inflammatory response to persistent infection
Repeated exposure gives more severe disease

28
Q

How is chlamydia treated?

A

Chlamydial infections can be treated with antibiotics (no resistance yet)
Tetracyclines, erythromycin

29
Q

What vacccines are available for chlamydia?

A

None available

30
Q

Why is it difficult to create a vaccine for chlamydia?

A

Disease is causes mainly by pathogenesis