Infectious Disease Flashcards

Vocabulary flashcards related to infectious diseases.

Mycoplasma pneumoniae

Smallest free-living bacterium; lacks cell wall; incorporates sterols into its plasma membrane; pleomorphic with 'fried egg' colony appearance; passes through 0.45 µm filter.

Mycoplasma pneumoniae pathogenesis

Attachment to respiratory epithelium via P1 adhesion protein causes ciliostasis, epithelial cell destruction, and impaired mucociliary clearance; acts as a superantigen.

Mycoplasma pneumoniae clinical features

Mild fever, malaise, headache, progressing to nonproductive cough and bronchopneumonia; complications include otitis media, erythema multiforme, myocarditis, pericarditis, and CNS involvement.

Mycoplasma pneumoniae diagnosis and treatment

Diagnosis: PCR, serology (complement fixation or enzyme agglutination). Treatment: erythromycin, tetracycline, fluoroquinolones (adults only).

Rocky Mountain Spotted Fever (RMSF) pathogenesis

Transmitted via wood tick bite; infects endothelial cells causing cell lysis, vascular leakage, thrombosis, vasculitis, and rash.

Rocky Mountain Spotted Fever (RMSF) clinical signs

High fever, headache, followed by petechial rash starting at extremities and involving palms/soles; complications: encephalitis, renal/respiratory failure.

Rocky Mountain Spotted Fever (RMSF) diagnosis and treatment

Diagnosis: Microimmunofluorescence (MIF) for outer membrane proteins, PCR. Treatment: doxycycline; fluoroquinolones as alternative.

Rickettsia prowazekii

Transmitted by human body louse causing epidemic typhus; thrives in crowded and unsanitary conditions.

Epidemic typhus symptoms and mortality

Fever, severe headache, chills, myalgias, and arthralgias; 40% develop petechial rash; complications include myocarditis and CNS disorders; mortality can reach 66% without treatment.

Chlamydia trachomatis developmental cycle

Elementary body (EB) - infectious, metabolically inactive; Reticulate body (RB) - noninfectious, metabolically active. EB enters cells, transforms to RB, replicates, and reverts to EB to exit.

Chlamydia trachomatis biovars and serovars

Trachoma: A, B, Ba, C; Urogenital: D-K; LGV: L1, L2, L2a, L3.

Trachoma

Chronic keratoconjunctivitis from serovars A-C; repeated infections cause conjunctival scarring, leading to inward eyelash growth (trichiasis) and corneal abrasion to blindness.

Chlamydia trachomatis urogenital symptoms

Males: urethritis with purulent discharge, epididymitis. Females: cervicitis, PID, salpingitis, often asymptomatic (up to 80%).

Lymphogranuloma Venereum (LGV)

Sexually transmitted infection by serovars L1-L3. Stage 1: painless ulcer; Stage 2: painful lymphadenitis with buboes; may rupture. Proctitis common in women and MSM.

Chlamydia trachomatis diagnosis and treatment

Diagnosis: DFA, PCR, culture on cell lines. Treatment: azithromycin, doxycycline; LGV requires 21-day tetracycline course; neonates treated with erythromycin.

Pathogens lacking peptidoglycan cell wall

Mycoplasma pneumoniae (no wall) and Chlamydia trachomatis (no peptidoglycan).

Rickettsial rash

Involves palms and soles and begins at extremities whereas measles starts at face/trunk.

Shared Rickettsia and Chlamydia diagnostic technique

Microimmunofluorescence (MIF) is used to detect outer membrane proteins and confirm species in both genera.