Bacterial STI II Flashcards
Treponema pallidum (Syphilis) (Characteristics)
- Thin, gram-negative SPIROCHETE
- Motile
- Microaerophilic (OXYGEN TOXICITY)
- Sensitive to heat, drying, or disinfectants
- Does not grow in cell-free culture; very difficult to grow in cell culture
Treponema pallidum (Syphilis) (Spirochete Structure)
- Gram negative cytology
- Flexible, peptidoglycan cell wall around which several AXIAL FIBRILS/ENDOFLAGELLA are wound
- The cell wall and axial fibrils are covered by an OUTER BILAYERED MEMBRANE (like outer memrane)
Treponema pallidum (Syphilis) (Detection)
- DARK-FIELD MICROSCOPY*
- Better illuminates unstained sample
Direct fluorescent antibody test, also works
Treponema pallidum (Syphilis) (Highest Incidence)
MSM (70%)
Treponema pallidum (Syphilis) (Transmission)
Sexual contact or Congenital
Treponema pallidum (Syphilis) (Primary Syphilis)
- One or more skin lesions (CHANCRES) at site of spirochete penetration (e.g. genitals, cervix, anus, oral area)
- Lesion is result of HOST RESPONSE to infection (inflammation)
- Abundant spirochetes are present at lesion
KEY: SINGLE Lesion is PAINLESS, INDURATED (Hardened)
Treponema pallidum (Syphilis) (Secondary Syphilis)
-Usually 2-8 weeks post chancre
FLU-LIKE SYNDROME (myalgias, anorexia, lymphadenopathy, etc.)
PROMINENT SKIN LESIONS dispersed over whole body including PALMS and SOLES of feets (HIGHLY INFECTIOUS)
May get raised lesions called CONDYLOMATA LATA in skin folds (e.g. in genitals) –> Soft, flat, moist, pink-tan papules and nodules
Treponema pallidum (Syphilis) (Latent Syphilis)
- ASYMPTOMATIC period* (lasts a few years to decades)
- Continued infection evidenced by SEROLOGIC tests
Transmission is possible through relapsing SECONDARY LESIONS, BLOOD TRANSFUSION, or transmission to fetus (CONGENITAL)
Treponema pallidum (Syphilis) (Tertiary (Late) Syphilis)
- VERY RARE, as Syphilis is treatable*
- 1/3 of untreated patients proceed to this
- Diffuse, chronic inflammation
- Can cause devastating destruction of virtually ANY ORGAN
- Granulomatous lesions GUMMAS may be found in bone, skin, and other tissues
Most devastating = Neurosyphilis or Cardiosyphilis
Treponema pallidum (Syphilis): Neurosyphilis Case Presentation
Progressive cognitive decline and behavioral changes over last 18 months
Mild to moderate dementia with impaired memory and attention and executive dysfunction
Pyramidal and extrapyramidal signs
MRI –> cortical atrophy and bilateral hippocampal atrophy
Treated with high-dose IV Penicillin
Tuskegee Syphilis Experiment
1932-1972: African American males with syphilis were not treated and monitored to see disease progression
Treponema pallidum (Syphilis) (Congenital Syphilis)
Similar to SECONDARY Syphilis
Signs:
- Rhinitis and Maculopapular Rash
- Teeth and bone malformation, blindness, deafness, and cardiovascular syphilis
- Conyloma lata (wart-like lesions around mouth and skin)
Saddle nose Hutchinson’s Teeth
Treponema pallidum (Syphilis) (Congenital Syphilis Triad)
Hutchinson’s Teeth, Blindness, and Deafness
What are the microbes that may pass from mother to fetus?
Toxoplasma gondii Rubella CMV HIV Herpes simplex virus type 2 Syphilis
“ToRCHHeS”
Treponema pallidum (Syphilis) (Diagnosis)
DARK-FIELD MICROSCOPY
Direct Fluorescent antibody microscopy
ANTIBODY DETECTION/SEROLOGY (Most common)
Culture is NOT available
Treponema pallidum (Syphilis) (Serology)
Nontreponemal Tests:
- Measures antibody directed against CARDIOLIPIN (lipid complex)
- Rapid plasma Reagina RPR and Venereal Disease Research Laboratory ***VDRL)
- Not directed at the organism*
Treponemal Tests:
- Detect antibody SPECIFIC to T. pallidum
- Fluorescent treponemal antibody (FTA-ABS)
- Microhemagglutination (MHA-TP)
- Gel-like beads*
- Directed at the organism*
Treponema pallidum (Syphilis) (Treatment and Prevention)
Treatment:
-Penicillin (Doxycycline or Azithromycin for patients allergic to Penicillin)
Prevention:
-Safe sex
Non-Gonococcal Urethritis (NGU) (Symptoms in Men vs Women)
Men:
- Blood in urine or semen
- Dysuria
- Discharge from penis
- Fever (rare)
- Frequent or urgent urination
- Itching, tenderness, or swelling in the penis or groin area
- Pain with intercourse
Women:
- Abdominal pain
- Dysuria
- Fevers and chills
- Frequent/urgent urination
- Pelvic pain
- Vaginal discharge
What are the causes of NGU?
Chlamydia (Most common)
Mycoplasma genitalium
Ureaplasma urealyticum
Mycoplasma and Ureaplasma (Characteristics)
Smallest free-living bacteria
DO NOT HAVE A CELL WALL (Resistant to PENICILLINS, CEPHALOSPORINS, VANCOMYCIN, and other abx that interfere with cell wall synthesis)
NOT STAINABLE
PLEOMORPHIC
Plasma membrane contains stolen STEROLS (unlike other bacteria)
Extracellular pathogens
Mycoplasma: Genitalium, pneumoniae, hominis
Ureaplasma: Urealyticum, parvum
Mycoplasma (Appearance)
Fried-egg like appearing colonies
M. genitalium and M. hominis
Normal inhabitants of GU tract
M. genitalium: NGU in males and cervicitis/PID in females
RESISTANT to Doxycycline; Azithromycin is effective
M. hominis: Associated with postpartum or postabortal fever and PID.
RESISTANT to Erythromycin; Doxycycline is effective
Ureaplasma (Characteristics)
Found in both normal and urethritic males
Common cause of NGU in males
Rarely found before puberty
Ureaplasma (Diagnosis and Treatment)
Men with NGU (suspect Ureaplasma) should be treated with DOXYCYCLINE (also active against Chlamydia)
Recurrent –> Azithromycin or Quinolones
