Diebel STDs Flashcards
What organisms most commonly produce urethritis?
N gonorrhoeae, C thrachomatis, M hominis
What organisms most commonly cause cervicitis?
C trachomatis, M. Genitalium
What organisms most commonly cause vaginitis?
T gavinalis, C albicans
What organisms most commonly cause vaginosis?
Gardnerella spp. Mobiluncus spp.
What organism is responsible for lymphogranuloma venereum?
C trachomatis
What organisms most commonly cause PID?
N gonorrhoeae, C trachomatis
What cells are seen on pap smear in an individual infected with HPV?
Koilocytes - abnormal giant cells
What strains of HPV are most common?
6, 11
What strains of HPV are most dangerous?
16, 18, 31, 33, 35
What type of screening test is done in order to identify the serotype of HPV?
PCR based screening test
What is the genetic classification of HPV?
DsDNA, group I, circular genome, icosahedral, nonevelopoed, papovaviridae, papillomavirus
What cells does HPV infect first? Why?
The basal cells - more likely to be undergoing replication and therefore would have host DNA polymerase
What does the host cell provide to the HPV virus?
DNA polymerase
In HPV, the E6 viral protein is responsible for what?
Ubiquinating p53 for degradation
What is the normal function of p53?
Senses DNA damage and triggers cell cycle arrest
In HPV infection, the viral protein E7 is responsible for what?
Interacts with and binds Rb, thereby releasing E2F; E2F can then go act as a transcription factor
What is the normal function of Rb protein?
Holds onto E2F and keeps it in cytosol so proliferation cannot occur
How is E2F normally released from Rb protein?
Cycline D and E phosphorylate Rb, resulting in the release of E2F
What organism typically causes a purulent discharge in males?
N gonorrhea
What microorganisms will typically cause clear discharge?
C trachomatis, M hominis, Ureaplasma urealyticum
What is the gram stain and morphology of N gonorrhea? Other characteristics?
Gram negative, diplococci; oxidase +, oxidizes glucose only
What type of media does N gonorrhea grow on?
Thayer Martin Media
What is in Thayer Martin Media?
Chocolate sheep’s blood, beef infusion, casein, starch, Vanco, Colistin, Nystatin, SXT
What is the effect of adding colistin to thayer martin media?
Kills most G - bacteria
What is the importance of adding SXT to thayer martin media?
G - organisms, particularly swarming proteus
What virulence factors does N gonorrhea have?
Specialized pili, endotoxin, capsule, IgA protease
What is the treatment for N gonorrhea urethritis?
Ceftriaxone (+ azithromycin for probable concurrent Chlamydia infections)
Prophylactic erythromycin drops can be given to a neonate to prevent what STI?
N gonorrhea
STI that is gram - diploccoi, oxidase +, oxidizes only glucose
N gonorrhea
What is the importance of the specialized pili found on N gonorrhea?
Allows attachment to mucosal surface, antigenic variation to evade host, prevents killing by phagocytosis
If PID is not treated, what could it progress to?
Fitz-hugh-curtis syndrome - involvement of liver capsule; also increases risk for ectopic pregnancy and infertility
What population of women have a higher incidence of N gonorrhea infection?
During menstruation or IUD
What serovars of Chlamydia trachomatis are responsible for conjunctiva?
A-C
What serovars of chlamydia are responsible for GU infections?
D-K
In a chlamydia trachomatis infection with serovars D-K, what cell type is the infection initiated at?
Columnar epithelium
Serovars L1-L3 of chlamydia trachomatis is responsible for what?
Lymphogranuloma venereum
How does lymphogranuloma venereum present?
Painless genital ulcer at site of infection; followed by painful inguinal LAD (formation of buboes)
What is the leading cause of blindness globally?
Trachoma serotypes A-C
What are seen on LM in infections of chlamydia trachomatis?
Intracellular inclusion bodies
What is the treatment for chlamydia trachomatis?
Azithromycin; consider ceftriaxone for gonorrhea
What are the two forms of C trachomatis? Which is infectious? Replicative?
Elementary body (infectious) and reticulate body (replication)
The MOMP on elementary bodies recognizes what on columnar epithelium?
Sialic acid
How does the elementary body avoid lysosomal degradation?
Has type III secretion system that inhibits the lysosome
In order to undergo replication, the reticulate body needs what? What type of replication does it undergo?
Needs ATP from the host cell; undergoes binary fission
What STI can cause painful ulcers?
Haemophilus ducreyi and HSV-2
Donovanosis forms what type of ulcers? What is the causative organism?
Painless; K granulomatosis
What is a Tzanck smear used for?
Herpes infected cells; will see giant multinucleated cells and Cowdry type A inclusion bodies
What is the genetic classification of HSV-2?
DsDNA, group I, linear, icosahedral, enveloped, herpesviridae, alpha
What is used for the treatment of HSV?
Acyclovir
HSV DNA encodes for what?
Many proteins required to promote viral DNA replication; including viral DNA-dependent DNA polymerase
What type of immunity is essential in controlling infection with HSV infection?
Cell mediated
Direct microscopic examination of cells from the base of a HSV lesion will show what?
Tanck smear shows multinucleated giant cells and Cowdry type A inclusion bodies
What is the MOA of acyclovir?
Inhibits DNA replication of viral genome as it is missing a 3’OH group
25 yo F presents iwth profuse yellow, foamy vaginal discharge with a foul odor. Additionally she has vulvar irritation and itching and dyspareunia. Physical exam reveals vaginal discharge, vulvar erythema, diffuse erythematous lesion of cervix (“strawberry” cervix). What organism is likely responsible?
Trichomonas vaginalis
What type of discharge is seen with Gardnerella?
Typically white to gray, moderate, malodorous
What type of discharge is commonly seen with C albicans?
Itchiness present, typically white, small amount and clumped
What is the typical discharge seen in an infection with Trichomonas vaginalis?
Frothy, yellow to green; foul smelling
What vaginal infections result in a pH >4.5?
Trichomoniasis (Trichomonas vaginitis) and vaginosis
The presence of volatile amines with a KOH amine test is a presumptive diagnosis for what?
Bacterial vaginosis
What is seen on a wet prep for bacterial vaginosis?
Clue cell
What is seen on a wet prep in trichomonas vaginitis infection?
Large, motile (flagellated organisms)
Describe the appearance of Trichomonads.
Small, pear shaped protozoa with 4 anterior flagella
What is the treatment for trichomonas vaginitis?
Metronidazole
What is the appearance of C albicans on LM?
Dimorphic fungi - bud (yeast) and hyphae (mold) form; also has pseudo hyphae and can see germ tubes
What is the most common cause of vaginitis?
C albicans
The presence of what in a smear of C albicans in indication that the yeast is growing rapidly and causing yeast infection?
Pseudo hyphae
Who are predisposed to vaginal infection with C albicans?
Diabetics, pregnant women, menstruation, HIV, disruption of normal biota (antibiotics)
What is treatment for C albicans?
Oral fluconazole; topical azole for for vaginal
Patient with CD4 count of 55, what other infections is he/she susceptible to?
A fumigatus; C albicans; CMV; cryptococcus neoformans (meningitis), cryptosporidium (chronic watery diarrhea), EBV (lymphoma), MAC; toxoplasma gondii
What STDs present with painless genital ulcers?
Syphillis (Treponema pallidum), lymphogranuloma venereum (chlamydia trachomatis), Donovanosis (K granulomatosis)
What are nonspecific serologic tests used for syphilis screening? If positive then what?
VDRL/RPR; confirm with FTA-ABS
Having ulcer disease increases the chances of infection with what?
HIV
During what stages is syphillis transmissible? And what stages is it not transmissible?
Primary and secondary = transmissible; latent and tertiary not transmissible
What is the appearance of a chancre?
Small, red hard bump that enlarges and breaks down, leaving a shallow crater with firm margins
If a sample was taken at the base of the chancroid, what could be done to visualize the organism? What would be seen?
Dark field microscopy; (gram -) spirochete
What is the treatment for syphillis?
Penicillin G - parenterally in large dose with benzathine or procaine
What are alternative drug therapies for syphillis if allergic to penicillin?
Tetracycline and erythromycin
