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- obligated intracellular
- cell wall lacks peptidoglycan layer
- transmission via direct contact- humans are only hosts
- major cause of STIs; higher in women among age 15-19 and 20-24
RB (reticulate body)-
- EB (elementary body)- infectious non reproductive particle attaches to and enters (via endocytosis) columnar epithelial cells that line mucous membranes.
- EB inhibits phagosome-lysosome fusion and isn't destroyed.
EB transforms into RB. Once enough RB have formed, some transform back into EB. RB is noninfectious, intracytoplasmic, reproductive form.
: collect epithelial cells, nucleic acid amplification tests (NAAT), direct immunofluorescence assay, enzyme immunoassay, cell culture
Treatment: Azithromycin (1 single dose) or doxycyclin (for 7 days)
: serotypes A, B, C: chronic conjunctivitis- a leading cause of preventable blindness
in the world. Inflammation scars pulls and folds the eyelid inward
so that the eyelashes rub against the conjunctiva and cornea which causes corneal scarring, secondary bacterial infections and ultimately blindness. in the US all newborns are given erythromycin
eye drops prophylactically.
: occurs bet 4-11 weeks of life.
- Urethritis/cervicits: D to K (non-invasive) remain in luminal surface of the epithelium --> ascending spread in genitourinary tract. symptomatic patients develop painful urination (dysuria) along w/ a thin to thick, mucoid discharge from the urethra.
- Urethra, rectum and conjunctiva of both sexes
- LPS- severe inflammatory response --> aggregation of lymphocytes and macrophages in submucosa--> necrosis, fibrosis and scarring
- Female: symptoms in 30% of cases
- o Mucopurulent discharge and/or dysuria
- o Complications if spread into uterus or fallopian tubes --> pelvic inflammatory disease (lower abdominal pain, low back pain, fever, bleeding bet menstrual period); permanent damage to fallopian tubes, uterus, and surrounding tissues --> chronic pelvic pain, infertility and ectopic pregnancy
- Male: symptoms in 75% of cases
- o Non-gonococcal urethritis: dysuria + thin urethral discharge
Cervicitis and Pelvic Inflammatory Disease (PID): cervix appears red, swollen and has yellow mucopurulent endocervical discharge. PID-infection spread upwards to involve the uterus, fallopian tubes and ovaries. on bimanual vaginal examination the patient may exhibit the "Chandelier sign."
- Lymphogranuloma Venereum: L1-L3 (invasive) --> organism travels via the lymphatics. Multiply w/in mononuclear phagocytes in regional lymph nodes --> characteristic granuloma formation
- Small painless ulcer at site of infection-->
- Spontaneously heals -->1-2 months later inflammation and swelling of local lymph nodes (inguinal adenopathy) --> painful buboes that enlarge and can rupture (draining fistulas) --> systemic manifestations: fever, chill, headache, myalgia
Aerobic gram (-) diplococcic in the cytoplasm of neutrophils, bean shaped, oxidase (+), fastidious growth requirement, no capsule, facultative intracellular, strict human pathogen, major reservoir: asymptomatic patients
Attachment and invasion of nonciliated epithelial cells (pili & opa proteins à parasite- directed endocytosis à trancytosis through BM to enter submucosa); survival in submucosa (Lipooligosaccharides (LOS), pili and opa proteins, Por proteins, IgA protease); spread and dissemination (localized to genital structure, in rare cases: disseminated gonococcal infection)
- incident in male and female are equal. anorectal, pharyngitis, conjunctvitis and disseminated infection are seen in both
- Females: cervix, 50% of infected women are symptomatic. can lead to PID
- Males: urethra (gonococcal urethritis), 75% of infections are symptomatic, purulent urethral discharge and dysuria
- Disseminated Gonococcal infections: generally in women because of asymptomatic infections.
- fever, migratory arthralgias, and skin rash over extremities but not head or trunk
- suppurative arthritis in wrist, knees and ankles
- skin and join infections in ~1% of cases
- possible endocarditis or meningitis
- leading cause of purulent arthritis
- culture (Thayer-Martin agar: chocolate agar), nucleic acid amplification tests
Treatment: 3rd generation cephalosporins (ceftriaxone)
Syphilis- Treponema pallidum
- highest among 20-24 and 25-29 yo males
- Thin, tightly coiled spirochetes
- no growth on artificial media
- humans are the only hosts
- susceptible to heat, drying and disinfectants
- requires close contact for successful transmission (sexual or transplacental)
- disease manifestations are caused by the host's own immune responses, such as inflammatory cell infiltrates, proliferative vascular changes, and granuloma formation
- Primary Syphilis
- one or more painless ulcer (chancres) at site of infection
- heals spontaneously w/ 2 months
- patient highly infectious
- Secondary Syphilis
- 6 weeks after the primary chancre has healed Clinical signs of disseminated disease: flu-like syndrome, lymphadenopathy, generalized maculopapular rash (entire body), condylomata lata (painless mucosal warty erosions),
- highly infectious
- almost any organ can become infected
- lesions resolve spontaneously and patient enters the latent stage
: asymptomatic (3-30yrs)...vertical transmission can happen.
- Tertiary Syphilis:
- Diffuse, chronic inflammation (delayed hypersensitivity reaction) --> organ and tissue destruction
- Gummatous syphilis: granulomatous lesions which eventually necrose and become fibrotic. Skin gummas are painless solitary lesions w/ sharp borders, while bone lesions are associated w/ deep gnawing pain
- Cardiovascular syphilis: aneurysm forms in the ascending aorta or aortic arch due to inflammatory destruction of vasa vasorum. antimicrobial therapy can NOT reverse these manifestations
- Neurosyphilis: subacute meningitis. Meningovascular syphilis (attach circle of willis). Tabes dorsalis (affects the spinal cord, specifically the posterior column and dorsal roots. Psychiatric symptoms. Argyll-Robertson pupil: midbrain lesion; pupil constricts during accommodation (near vision) but doesn't react to light.
Early congenital syphilis
- Congenital syphilis:
- in utero infections can lead to intrauterine death, congenital abnormalities (mulitorgan malformation may be obvious at birth), silent infections until 2 years of age
occurs w/in 2 years and is like secondary syphilis w/ widespread rash and condyloma latum. involvement of the nasal mucous membrances leads to a runny nose called the "snuffles"
Late congenital syphilis:
tertiary syphilis CV involvement rare. neurosyphilis is same as adults and eighth nerve deafness
is common. Bone and teeth are freq involved. perosteal (outer layer of bone) inflammation destroys the cartilage of the palate and nasal septum, giving the nose a sunken appearance called saddle nose
. a similar inflammation of the tibia leads to bowing called saber shins
. The upper central incisors are widely spaced w/ a central notch in each tooth (Hutchinson's teeth
) and molars have too many cusps (mulberry molars
syphilis doesn't damage the fetus until the 4th mths of gestation, so Rx the mother w/ antibiotic prior to this can prevent congenital syphilis
Nonspecific treponemal tests
- Darkfield Microscopy- live motile bacteria
- Direct fluorescence antibody test- done on oral or rectal specimens
- Silver staining- demonstrate the organism in biopsy material/tissue specimens
: infection w/ syphilis results in cellular damage and the release into the serum of a number of lipids, including cardiolipin and lecithin. Venereal Disease Research Laboratory (VDRL) and Rapid Plasma Reagin (RPR) test. False + results linked to other disease
- Specific treponemal tests:
- Indirect Immunofluorescent Treponemal Antibody-Absorption (FTA-ABS): mix patient's serum w/ standardized nonpathogenic strain of Treponema which removes antibodies shared by both Syphillus and normal human flora strains. the remaining serum is added to a slide covered w/ syphillus
- MHA-TP: microhemagglutination test. antigens attached to surface of erythrocytes; agglutination in presence of antibody.
- Penicillin; Doxycycline for penicillin-allergic patients
Chancroid or Soft Chancre
- Small, pleomorphic gram (-) rod
- very susceptible to dehydration, spread by sexual contact
- Chancroid= tender papule w/ an erythematous base; can progress to painful ulceration w/ associated inguinal lymphadenopathy
Culture on chocolate agar
Rx: Erthromycin, azithromycin or ceftriaxone
Granuloma inguinale or Donovanosis
- Intracellular encapsulated gram (-) rod
- granulomatous ulcers that bleed on contact; inguinal lesion in some
Examination on Wright-or Giemsa- stain --> clusters of encapsulated coccobacilli in cytoplasm of mononuclear cells called Donovan Bodies
Gardnerella vaginalis (Haemophilus vaginalis)
- gram-variable coccobacilli, facultative anaerobes
- Shift in vaginal flora: Lactobacillus spp. replaced by Gardnerella vaginalis and anaerobes. Vaginal pH > 4.5
- White or gray vaginal discharge (unpleasant odor); dysuria- burning, Clue cells: vaginal epithelial cells that contain tiny pleomorphic bacilli w/in the cytoplasm, untreated-PID, preterm delivery.
- Rx: Metronidazole
- flagellate protozoa, only trophozoite form- replicates by binary fission, no cyst form- doesn't survive in external environment
- one of the most common STI in young, sexually active women
- infected form: trophozoite; sexual contact; transmission to newborn from infected mother during delivery
- contact dependent damage to epithelium
- women (often symptomatic): vaginitis w/ purulent discharge (foamy, foul-smelling, yellow-green vaginal discharge), vulvar and cervical lesions (strawberry vagina), dysuria, premature rupture of membranes, preterm delivery, low birthweight; Men (rarely symptomatic): mild urethritis
- Diagnosis: motile trophozoites in methylene blue wet mount
- Rx: Metronidazole or Tinidazole
- round or oval budding yeast; polymorphic; opportunistic pathogen- member of normal oropharyngeal, GI and genital flora
- Mannoproteins (adherence to mucosal surface); Hyphae formation (secrete proteinases and phospholipases) --> killing of epithelial cells; resistance to phagocytosis
- Pruritis & erythema of vulvar area; cheesy vaginal discharge
- Diagnosis: KOH preparation: budding yeast and pseudohyphae; Germ tubes formation after 2h incubation in serum;
- Rx: Fluconazole