Microbiology Exam 5 Answers

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Who are the most susceptible to genital tract infecitons?
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Women and children
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What two STIs are increasing in incidence and prevalence
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Chlamydia and HPV
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Where do infections usually localize in Males?
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Most infections expect syphiis are limited to the urethra; occasionally they can infect the prostate
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Where do infections occur in females?
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Most parts can be infected; perineum, vagina, cervix, uterus, fallopian tubes, pelvic cavity
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How does the cellular structure of the vaginal and cervical epithelium change?
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Under hormonal control
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What pH is the adult vagina? What pH is the post menstrual vagina
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Acidic, neutral
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Where is the natural bacterial flora located in men and what is it?
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In the anterior urethra, staphylococcus
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At puberty, what is the normal flora of the female genital tract?
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Lactobacillus, a few enterococci and yeasts
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What does the vagina secrete, how is it produced?
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Glycogen, fermented to acid by Lactobacillus
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What keeps the uterus and fallopian tubes sterile?
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The cervical plug
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What non-STI do men occasionally get?
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Prostatitis
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What is usually associated with vaginal infections between puberty and menopause?
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Disruption of the normal flora by antibiotics; super infections
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How are these infections diagnosed?
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Clinically; each has a typical presentation according to volume, appearance and pH of the discharge
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What causes vaginosis?
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Disruption of the lactobacillus normal flora due to antibiotic therapy, douching
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What does vaginosis change in the vagina? What are signs and symptoms?
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Turns pH neutral, get vaginal discharge, smell, itching, burining
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What replace lactobacillus in vaginosis
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Anaerobes and Gardnerella vaginalis
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What drugs are typically used to treat vaginosis?
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Metronidazole or clindamycin
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What microorganism causes yeast vaginosis?
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Candida albicans
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What are the symptoms of yeast vaginosis?
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Itching, burning, white discharge
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How is yeast vaginosis diagnosed?
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Absence of lactobacilli, presence of yeast
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Explain the treatment of yeast vaginosis
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Antifungal creams (Nystatin) or tablets (fluconazole)
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What microorganism can cause Toxic Shock Syndrome
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S. aureus makes a toxin TSST-1 that is absorbed and causes systemic toxicity
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What are the symptoms of TSS?
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Fever, headache, vomiting, diarrhea, rash, hypotension
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What is TSS associated with?
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Highly absorbent tampons
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How are STIs spread
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Requires direct contact between mucous membranes and exchange of body fluids. Not limited to genital contact, not limited to male-female contact
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When did STIs begin rising in numbers
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1960s
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What are some reasons for the increase in STIs
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Birth control drugs replaced condom use, asymptomatic carriers, lack of immunity, persistent viruses
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How many STis are reportable to the CDC or health department
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4; all others cannot be traced
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What is the epidemiology of Gonorrhea?
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Neisseria gonorrhoeae (gonococcus); Gram negative diplococci, often intracellular
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What are the signs and symptoms of Gonorrhea?
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2-5 day incubation period, Male urethritis with copious purulent discharge, Female cervical infection, dysuria, vaginal discharge, pelvic pain
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Describe the pathogenesis of Gonorrhea
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Bind to non-ciliated mucosal epithelium (urethra, cervix, pharynx, conjunctiva, anus via pili); changes surface antigens to avoid the immune response
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What is the diagnosis and treatment of Gonorrhea
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Urethral or vaginal amplified DNA test; treatment is single-dose IM ceftriaxone; not penicillin
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What is epidemiology of Chlamydia?
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Chlamydia trachomatis; an intracellular pathogen
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Describe the two-stage life cycle of Chlamydia
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Elementary bodies spread from person to person
Attaches to host receptors, enters cells, forms a reticulate body
Replicates to spread again
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What is the fastest increasing reportable STI, especially in high school and college age
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Chlamydia
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Explain the pathogenesis of Chlamydia
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7-14 day incubation (longer than gonorrhea)
Male urethritis has less discharge than gonorrhea, can be subclinical or asymptomatic
Female dysuria, vaginal bleeding, discharge, pelvic pain; can spread to salpingitis, infertility
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Describe the diagnosis and treatment of Chlamydia
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Urethral or cervical specimen, PCR DNA test
Treated using intracellular antibiotics; macrolides (azithromycin) are best
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What is the microorganism that causes Syphilis
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A spirochete; Treponema pallidum
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What are the three stages of Syphilis
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Primary; hard chancre at the site of infection, goes away
Secondary; spreads systemically, causes a rash
Tertiary; immune response causes neurologic disorders
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How is syphilis treated?
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Penicillin
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Where was Syphilis discovered?
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Tuskegee program
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Describe epidemiology of Herpes Simplex Virus
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Type 2- a persistant virus; can be treated but never cured
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Explain the pathogenesis of Herpes Simplex Virus
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Forms vesicular lesions on the penis or vuvla; lesions last 2 to 3 weeks, itching, pain, fever; direct contact during the infectious period spreads the virus to the partner; can be congenital
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How is Herpes Simplex Virus diagnosis
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Culture or PCR of genital lesions or CSF
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How is Herpes Simplex Virus treated?
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Treatment by acyclovir, valacyclovir, famciclovir. Reduce the symptoms, do not eliminate the latent virus from the sensory ganglia. Treatment episodes and chronic suppression
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What is the most common STI
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HPV
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What does HPV cause?
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Genital warts: raised on the penis, vulva, anus; flat on cervix.
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True or False: All warts caused by HPV will go away
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False, some cause cervical cancer
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How is HPV detected?
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Visually, by Pap smear, or DNA test
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How are HPV warts treated?
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Excision, laser, freezing
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What microorganism causes Trichomonas?
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Trichomonas vaginalis, a flagellate
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True or False: Men who have Trichomonas are generally asymptomatic
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True
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Which STIs pathogenesis is described below: Irritates vagina, itching, burning, yellow foamy discharge
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Trichomonas
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How is Trichomonas diagnosed
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Microscopic exam of discharge, see on a pap smear
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How is Trichomonas treated
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Metronidazole
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What are Crab lice caused by?
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Phthirus pubis
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How do crab lice survive?
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Sucking blood
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How are crab lice transmitted
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By direct contact; 2mm long female lays eggs in pubic hair

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