Non Gram Stain Flashcards
Mycoplasma pneumoniae
ATYPICAL WALKING PNEUMONIA: insidious onset, headache, nonproductive cough, patchy or diffuse interstitial infiltrate
Pleomorphic, no cell wall.
Dx: x Ray, culture on Eaton agar.
Tx: macrolides, doxycycline or Fluoroquinolona
SPirochetes
- Treponema: syphilis
- Borrelia : Lyme disease
- Leptospira: leptospirosis
Lyme disease
Borrelia burgdorferi
Transmision: Ixodes deer tick
Natural reservoir: mouse
Common in northeastern United state
Spring/summer seasons
Patient with influenza like symptoms and erythema migrans
STAGES:
1- early localized: bull’s eye target rash
2- early disseminated (hematogenously): fatigue, chills and fever, headache, muscle and joint pain, swollen lymph nodes, BELL PALSY.
3- Late persistent: encephalopathies, chronic arthritis.
Dx: ELISA, Western blot for confirmation.
Tx: doxycycline
Leptospira interrogans
LEPTOSPIROSIS
- spirochete with terminal hook
- found in water contaminated with animal urine ( hawaii)
- Symptoms : flu like symptoms, myalgias, jaundice, photophobia with conjunctival suffusion
- complication: Weil diasease: icterohemorraghic leptospirosis: sever form with jaundice and azotemia from the liver and kidney dysfunction, fever, hemorrhage and anemia.
- Dx: serodiagnosis or agglutination test , dark field microscopy insensitive.
- tx: penicillin g or doxycycline
Treponema
TREPONEMA PALLIDUM
Spirochete: spiral with axial filament (endoflagellum), gram negative bacteria not seen it on gram stein, only visualized by dark- field or fluorescent antibody.
-reservoir: human genital tract
- transmission: sexually or across placenta
- Pathogenesis :
- Disease: SYPHILIS ( 3 stages)
- Diagnosis:
1) Visualize organisms by inmunofluorescense or dark field microscopy
2) Serology: 2.1) Nontreponemal antibody (VDRL): very sensitive in primary and secondary syphilis but not specific, confirm with FTA-ABS. 2.2) Specifics test for treponemal antibody (FTA-ABS) : usually remain positive all live
- Treatment: Benzathine penicillin for primary and secondary syphilis.
Penicillin G for congenital and late syphilis .
Consequences of treatment: JARISCH-HERXHEIMER REACTION: flu like syndrome ( fever, chills, headache, myalgias) after 24hrs antibiotic are started due to killed bacteria releasing toxins
VDRL FALSE POSITIVE
Viral infection
Drugs
Rheumatic fever
Lupus, leprosy, Lyme disease
Stages of syphilis
1) PRIMARY SYPHILIS: painless chancre, non tender, clean, indurated edge. CONTAGIOUS. Heals Spontaneously. Dx: dark field microscopy to visualized treponemes. VDRL + in 80%.
2) SECONDARY SYPHILIS (1-3 months later) : disseminated disease with constitutional symptoms: Maculopapular rash diffuse (including palms and soles) , condylomata Mata (smooth, moist, painless, wart-like white lesions on genitals) , lymphadenopathy, patchy hair loss.
Dx: VDRL/FAT-ABS.
3) Latent syphilis: none clinical manifestations, serology positive
5) TERTIARY SYPHILIS (30% of untreated years later) : GUMMAS (chronic granulomas), aortitis (vasa vasorum destruction), neurosyphilis (general paresis), Argyll Robertson pupils ( constricts with accommodation but is not reactive to light.
For neurosyphilis: test spinal fluid with VDRL, FTA-ABS and PCR.
CONGENITAL SYPHILIS
Facial abnormalities:
- Rhagades ( linear scars at angle of the mouth)
- Snuffles : nasal discharge
- Saddle nose
- Notched teeth, mulberry molars and short maxillar
- saber shins
- deafness (VIII nerve damage)
Gardenerella vaginalis
Pleomorphic, gram variable rod.
Vaginal normal flora, overgrowth with increased of pH .
Associated with sexual activity but it is not transmitted sexually
Disease: Bacterial Vaginosis: GRAY vaginal discharge with a fishy smell, no painful.
Dx: clinical, pH> 4.5, CLUE CELLS (epithelial cells covered with gardnerella) , amine whiff test positive (mixing discharge with 10% KOH enhances fishy odor)
Tx: metronidazole or clindamycin
Chlamydia trachomatis
- FEATURES:
- obligate intracellular bacteria
- elementary body( infested body) / reticulate body ( is the form of the bacteria replication)
- not seem on gram stain
- cannot make ATP
- cell wall lacks muramic acid
- Reservoir: human genital tract and eyes
- Transmission: sexual contact and vaginal delivery at birth
- Pathogenesis: infection of nonciliated columnar or cuboidal epithelial cells of mucosal surfaces leads to granulomas outs response and damage.
- Diseases: 1) TYPES D-K: Nongonococcal urethritis, cervicitis, PID. Inclusion conjunctivitis and/or pneumonia in neonats/infants.
3) Lymphogranuloma venereum : serotypes L1, L2 and L3; small, painless ulcers on genitals, swollen painful inguinal lymph nodes. Tx: doxycycline
4) Trachoma ( serotypes A, B and C) : leading cause of preventable infectious blindness. Follicular conjuctivitis in Africa. - Dx: PCR, culture in tissue or embryonated eggs, ELISA
- TX: Doxycycline or Azythromycin
- Prevention: erythromycine
Rocky Mountain spotted fever
Rickettsia rickettsii
- vector: tick
- occurs primarily in the South Atlantic states, especially North Carolina.
- Classic Triad: Headache, fever, rash (flu like symptoms) , tick bite
- petechial Rash, typically starts at wrists and ankles and then spreads to trunk, palms and soles. (Centripetal rash)
- Dx: Weil- Felix (+), serological IFA test, clinical symptoms and tick bite.
- Tx: Doxycycline
DD of Rocky Mountain spotted fever
Coxsackievirus A infection: hand, foot and mouth disease
Second syphilis
Ehrlichiosis
Ehrlichia
Vector is tick
Disease: similar to Rocky Mountain spotted fever but without rash, leukopenia, thrombocytopenia, morulae ( mulberry-like inclusions inside infected cells )
Dx: giemsa stain (morulae), serology, DNA probe
Tx: doxycycline
