Mycoplasma and Ureaplasma Dr. R. K. Kalyan Associate Professor Microbiology Dept. Kgmu mycoplasma

Mycoplasmas of Humans

• Parasitic
• Established pathogens: M. pneumoniae
• Presumed pathogens: M. hominis, U. urealyticum
• Non pathogenic: M. orale, M. buccale, M. genitalium, M. fermentans
• Saprophytic – present mainly on skin & in mouth.

Pathogenicity

• Produce surface infections – adhere to the mucosa of respiratory, gastrointestinal & genitourinary tracts with the help of adhesin.
• Two types of diseases:
• Atypical Pneumonia
• Genital infections

Pathogenicity cont’

• Adherence
• P1 pili (M. pneumoniae)
• Movement of cilia ceases (ciliostasis)
• Clearance mechanism stops resulting in cough
• Toxic metabolic products
• Peroxide and superoxide
• Inhibition of catalase
• Immunopathogenesis
• Activate macrophages
• Stimulate cytokine production
• Superantigen (M. pneumoniae)
• Inflammatory cells migrate to infection and release TNF-a then IL-1 and IL-6

Pathogenicity cont’

Mycoplasmal pneumonia

• Also called Primary Atypical Pneumonia/ Walking pneumonia.
• Seen in all ages
• Incubation period: 1-3 wks
• Transmission: airborne droplets of nasopharyngeal secretions, close contacts (families, military recruits).

Mycoplasmal pneumonia

• Gradual onset with fever, malaise, chills, headache & sore throat.
• Severe cough with blood tinged sputum (worsens at night)
• Complications: bullous myringitis & otitis, meningitis, encephalitis, hemolytic anemia

Diseases Caused by Mycoplasma

• Organism Disease
• M. pneumoniae Upper respiratory tract disease, tracheobronchitis,
• atypical pneumonia, (chronic asthma?)
• M. hominis Pyelonephritis, pelvic inflammatory disease,
• postpartum fever
• M. genitalium Nongonococcal urethritis
• U. urealyticum Nongonococcal urethritis,
• (pneumonia and chronic lung disease in
• premature infants?)