3.29 Mycoplasma and Ureaplasma

Microbiology review for the USMLE Step 1 Exam

• Mycoplasma and Ureaplasma are bacteria without cell walls, making them invisible to gram stain.
• They cause respiratory and genital infections and have a cell membrane containing cholesterol.
• Main species causing infections in humans include Mycoplasma pneumoniae, Mycoplasma genitalium, Mycoplasma hominis, and Ureaplasma urealyticum.
• Mycoplasma pneumoniae causes atypical pneumonia and is spread through respiratory droplets. Symptoms include non-specific fever, headache, and sore throat, and diagnosis is done through PCR. Treatment is with macrolides, tetracyclines, and fluoroquinolones.
• Mycoplasma genitalium, Mycoplasma hominis, and Ureaplasma urealyticum cause genital infections and are acquired through sexual contact. They cause dysuria, urgency, urethral discharge, and pelvic pain. Diagnosis and treatment are similar to Mycoplasma pneumoniae with PCR and tetracyclines being the preferred treatment.