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MYCOPLASMA

MYCOPLASMA. II MBBS Dr Ekta Chourasia Microbiology, GMCA. Mycoplasma No cell wall Pleomorphism Fried egg colonies Diene’s stain Primary atypical/ walking pneumonia Genital infections. Cold agglutination test Cell culture contamination Ureaplasma Hydrolysis of urea. Key Words.

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MYCOPLASMA

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  1. MYCOPLASMA II MBBS Dr Ekta Chourasia Microbiology, GMCA

  2. Mycoplasma No cell wall Pleomorphism Fried egg colonies Diene’s stain Primary atypical/ walking pneumonia Genital infections Cold agglutination test Cell culture contamination Ureaplasma Hydrolysis of urea Key Words Dr Ekta,Microbiology, GMCA

  3. MYCOPLASMA • Smallest (<1µ) free-living micro organisms, lack cell wall. • 1st member of this group – isolated by Nocard & Roux (1898) – caused bovine pleuropneumonia. • Later, many similar isolates were obtained from animals, human beings, plants & environmental sources – called as “pleuropneumonia like organisms”(PPLO). Dr Ekta,Microbiology, GMCA

  4. MYCOPLASMA • 1956- PPLO replaced by Mycoplasma. • Myco : fungus like branching filaments • Plasma : plasticity • highly pleomorphic – no fixed shape or size - Lack cell wall. • Can pass through bacterial filters. Dr Ekta,Microbiology, GMCA

  5. 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. Dr Ekta,Microbiology, GMCA

  6. 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 Dr Ekta,Microbiology, GMCA

  7. Mycoplasmal pneumonia • Also called Primary Atypical Pneumonia/ Walking pneumonia • Seen in all ages • Incubation period: 1-3 wks • Transmission: airbornedroplets of nasopharyngeal secretions, close contacts (families, military recruits). Dr Ekta,Microbiology, GMCA

  8. 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 Dr Ekta,Microbiology, GMCA

  9. Laboratory Diagnosis • Specimens – throat swabs, respiratory secretions. • Microscopy – • Highly pleomorphic, varying from small spherical shapes to longer branching filaments. • Gram negative, but better stained with Giemsa. Dr Ekta,Microbiology, GMCA

  10. Laboratory Diagnosis • Isolation of Mycoplasma (Culture) – • Semi solid enriched medium containing 20% horse or human serum, yeast extract & DNA. Penicillium & Thallium acetate are selective agents. (serum – source of cholesterol & other lipids) • Incubate aerobically for 7 -12 days with 5–10% CO2at 35-37°C. (temp range 22- 41°C, parasites 35- 37°C, saprophytes – lower temp) Dr Ekta,Microbiology, GMCA

  11. Laboratory Diagnosis • Typical “fried egg” appearance of colonies - Central opaque granular area of growth extending into the depth of the medium, surrounded by a flat, translucent peripheral zone. • Colonies best seen with a hand lens after staining with Diene’s method. • Produce beta hemolytic colonies, can agglutinate guinea pig erythrocytes. Dr Ekta,Microbiology, GMCA

  12. Fried egg colonies Dr Ekta,Microbiology, GMCA

  13. Identification of Isolates • Growth Inhibition Test– inhibition of growth around discs impregnated with specific antisera. • Immunofluorescence on colonies transferred to glass slides. • Serological diagnosis • PCR Dr Ekta,Microbiology, GMCA

  14. Identification of Isolates • Serological diagnosis • Specific tests – IF, HAI • Non specific serological tests – cold agglutination tests (Abs agglutinate human group O red cells at low temperature, 4C). 1:32 titer or above is significant. Dr Ekta,Microbiology, GMCA

  15. Ureaplasma urealyticum • Strains of mycoplasma isolated from the urogenital tract of human beings & animals. • Form very tiny colonies - hence called T strain or T form of mycoplasmas. • Hydrolyzes urea Dr Ekta,Microbiology, GMCA

  16. Genital Infections • Caused by M. hominis & U. urealyticum • Transmitted by sexual contact • Men - Nonspecific urethritis, proctitis, balanoposthitis & Reiter’s syndrome • Women – acute salpingitis, PID, cervicitis, vaginitis • Also associated with infertility, abortion, postpartum fever, chorioamnionitis & low birth weight infants Dr Ekta,Microbiology, GMCA

  17. Mycoplasma & HIV infection • Severe & prolonged infections in HIV infected & other immunodeficient individuals Dr Ekta,Microbiology, GMCA

  18. Mycoplasma as cell culture contaminants • Contaminates continuous cell cultures maintained in laboratories • Interferes with the growth of viruses in these cultures. • Mistaken for viruses. • Eradication from infected cells is difficult. Dr Ekta,Microbiology, GMCA

  19. Treatment • Tetracycline, Erythromycin & Clarithromycin – drug of choice • Resistant to antibiotics which interfere with bacterial cell wall synthesis. • Newer macrolides & quinolones being used now. Dr Ekta,Microbiology, GMCA

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