Sexually Transmitted Bacterial Infections Flashcards by shajida begum

What is the cause of gonorrhoea?

Neisseria gonorrhoea.

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What are the two main categories of genitourinary infections?

Primary infections due to a sexually transmitted pathogenic organism.
Infections due to members of the resident flora.

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What is the morphology of NG?

Aerobic. Gram negative diplococci.
Non-motile, non-spore forming and has a pili.
Fastidious growth requirements.

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What is the pathology?

Attachment to non-ciliated columnar epithelial cells.
Cells damaged by toxins.
Alters protein antigens frequently.

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What are the symptomatic infections that arise?

Urethritis, proctitis, pharyngitis, conjunctivitis.

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What are the methods for diagnosis?

Gram stain.
Culturing (Thayer-Martin media)
Non-amplified DNA probe tests.
Ligase Chain Reaction (LCR) assays.

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Name drugs used for treatment.

Azithromycin or Doxycycline

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Name the drugs that it is resistant to.

Erythromycin, amoxicillin.

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Control.

Screening, partner notification, presumptive treatment of sex contacts.

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What needs to be considered for a gonorrhoeal infection?

Check for syphilis and possible chlamydia co-infection.

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What is the cause of syphilis?

Treponema pallidum.

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What is the pathophysiology of syphilis?

Spirochete, rotary motion, requires a break in squamous or columnar epithelium. Replication is slow.

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How many stages are there for syphilis?

Primary, secondary, latency and tertiary.

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Describe the clinical manifestations of primary syphilis.

Incubation period: 3 weeks

Formation of chancre which resolves in 1-5 weeks. Highly infectious.

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How would you identify syphilis using fluorescent techniques?

Antibody in the patients serum binds to bacteria and is visualised by a fluorescent dye.

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What are the clinical manifestations of secondary syphilis?

Dissemination of spirochetes. 
Signs and symptoms include rash (whole body)
Mucous patches
Malaise
Headache
Lymphadenopathy
Condylomata lata
Alopecia (baldness)
Resolves in 2-10 weeks.

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Describe the latency stage.

Conversion from an acute to chronic infection, no longer infectious.

Late latent
After first year
Relative immunity to relapse
Resistant to reinfection

Describe the tertiary stage.

Complications arise including the cardiovascular system, neurosyphilis and gummas (small soft swelling in the liver, brain, testes and heart)

Treatment.

Penicillin.

What are the characteristics of chlamydia spp?

Small gram negative bacteria
Obligate intracellular bacteria 
Infect columnar epithelial cells
Survive by replication that results in the death of the cell
Takes on two forms in its life cycle:
Elementary body 
Reticulate body

What is the epidemiology for chlamydia?

Common in UK.

What are the risk factors?

Adolescence, new or multiple sex partners, history of STD infection, presence of another STD, oral contraceptive user, lack of barrier contraception.

How is it transmitted?

Transmission is sexual of vertical.
Highly transmissible 
Incubation period 7-21 days 
Reinfection is common
Prenatal transmission results in neonatal conjunctivitis in 30%-50% of exposed babies.

What are the types of infection that arise from C. trachomatis?

Ocular
Inclusion conjunctivitis
Trachoma

Genital
Urethritis
Pelvic inflammatory disease

Pneumonia

What are the clinical features for inclusion conjunctivitis?

Acute follicular conjunctivitis | Caused by C. trachomatis types D-K

Treatment.

Infants: Erythromycin Adults: tetracycline

What is the epidemiology?

Neonatal (acquired in birth canal) | In older children and adults

What are the clinical features of trachoma?

``` Severe follicular conjunctivitis With pannus (invasion of cornea with blood vessels...leads to corneal scarring and blindness) ```

What is the epidemiology?

Major cause of blindness in the world Tropical developing countries Spread by contact or contaminated flies

Treatment.

Tetracycline, erythromycin.

Describe the cervicitis and urethritis infections that arise from C. trachomatis.

Cervicitis Majority is asymptomatic Local signs of infection include: mucopurulent endocervical discharge Urethritis Usually asymptomatic Symptoms include: dysuria (painful urination), frequency pyuria (need to pee frequently).

What complications arise in women?

Pelvic inflammatory disease Reiter's syndrome Fitz-Hugh-Curtis syndrome

What methods are used for diagnosis?

Culture (gold standard, variable sensitivity, high specificity, not suitable for widespread screening) PCR detection tests Serology.

What drugs are used for treatment in uncomplicated genital chlamydial infections?

Azithromycin, doxycycline.

Drugs for pregnant women?

Erythromycin, amoxicillin.

Why is screening performed?

Reduces the incidence of PID by more than 50%. Most infections are asymptomatic. And it also decreases the prevalence of infection in the population and reduces the transmission of the disease.

What can't spirochetes of T. pallidum be seen by light microscopy?

Because their too thin.

How does syphilis escape the immune system?

The outer membrane proteins for T. pallidum can adhere to the surface of host cells, virulent spirochetes produce hyaluronidase which may facilitate perivascular infiltration. Spirochetes are also coated with host cell fibronectin which can protect against phagocytosis.

What was the incidence of syphiliis?

Use of birth control pills in the 1960s, gay bath houses in 1970s and increased prostitution related to crack cocaine use in the 1990s.

What are the two main types of serology tests for syphilis?

Venereal disease research laboratory test and rapid plasma reagin test.