extras Flashcards
How does C. diphtheriae cause damage, which organs are most badly affected?
It releases an AB exotoxin that prevents protein synthesis within cells. Intoxication of the heart and kidneys is fatal.
Describe the structure of the influenza virus
It is a RNA virus consisting of 8 weakly linked RNA segments, surrounded by a capsule with spike proteins (haemagglutinin and neuraminidase)
How does bordetella pertussis cause disease
Releases tracheal cytotoxin which incapacitates ciliated cells, resulting in buildup of mucus and bacteria in the lower RT
Why does the convalescence period in pertussis take months following treatment?
Erythromycin eliminates the bacteria, but ciliated cells must also be replenished
What are the differences between pneumococcal pneumonia and H. pneumoniae pneumonia? (3)
S. pneumoniae is gram positive whereas H. pneumoniae is gram negative.
Strep occurs due to lowered immunity in a healthy carrier, while H occurs in those who are immunocompromised (alcoholic, diabetic, cancer, poor nutrition)
Strep can be treated with penicillin/optichin while H is resistant to penicillin so penicillinase resistant 2nd gen cephalosporins are used
What are two similarities of Q fever and chlamydial pneumonia/ ornithosis
Both are obligate intracellular and cause atypical pneumonia
What is a major complication of Q fever
Endocarditis
Where does blastomycosis begin and where does it spread?
Begins with infection of the lungs and spreads to skin to cause cutaneous ulcers
How is leptospirosis transmitted
Dogs and cats shed the bacteria in their urine, which contaminates water. It can then enter the body through damaged skin or the digestive tract.
What are two complications of leptospirosis
Severe liver and kidney disease
How much more likely are females to develop gonorrhoea after a single exposure than males
Thrice (60-90% compared to 20-35%)
Gonorrhoea symptoms
Pus and painful urination
What part of the female body is infected and why- gonorrhoea
Cervix (columnar epithelium) and not vagina (stratified squamous)
How is the causative agent of syphilis cultured
Treponema pallidum can be grown in cell cultures only
Are antibodies effective against treponema pallidum? Why/ why not?
No, CMI only due to lipid outer layer of the bacteria ‘teflon coated’
Which 3 factors may contribute to increased risk of vaginitis and why
Pregnancy, oral contraceptives and use of broad spectrum antibiotics. Suppress the growth of lactobacilli (normal flora) which obtain energy from sexual hormones, leading to opportunistic infection
What treatments can be used to restore acidity of the vagina
Acetic acid gels and replacement lactobacilli
What symptoms are the same vs different for males v females with genital herpes
Vesicles appear on external genitals (female) vs base of penis (male)
Both have dysuria (painful urination) and trouble walking
How is genital herpes cured
It is not curable, antivirals like acyclovir could possibly be used
Why is topical podofilax/ podophyllum used to treat genital warts
Caused by human papillomavirus
Podofilax contains zinc which inhibits viral replication
What major condition is genital warts associated with
Cervical cancer
How is lymphogranuloma venereum diagnosed
Iodine staining of pus from lymph nodes
Common feature between 3 common causes of bacterial meningitis. How does this relate to type of vaccine used?
All capsulated. All vaccines are based on the capsular antigens
Haemophilus influenza vaccine is based on
Hib capsular antigen
