MYCOPLASMA and Ureaplasma

1. MYCOPLASMA and Ureaplasma

2. MYCOPLASMA • Smallest free-living micro organisms • lack cell wall. • Size: Varies from spherical shape (125-250nm to longer branching filaments 500-1000 nm in size. • Pass through a bacterial filter. • Isolated by Nocard & Roux (1898) –bovine pleuropneumonia (PPO)

3. Pleuropneumonia like organisms”(PPLO) • Later, many similar isolates were obtained from animals, human beings, plants & environmental sources – called as “Pleuropneumonia like organisms”(PPLO).

4. MYCOPLASMA • Eaton (1944) first isolated the causative agent of the disease in hamsters and cotton rats. • Also known as Eaton agent. • 1956- PPLO replaced by Mycoplasma. • Myco : fungus like branching filaments • Plasma : plasticity • highly pleomorphic – no fixed shape or size - Lack cell wall.

5. Morphology and Physiology • Require complex media for growth • Facultative anaerobes: Except M. pneumoniae - strict aerobe • No cell wall means these are slow growing & resistant to penicillins, cephalosporins and vancomycin, etc.

6. Mycoplasmas of Humans

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

8. Pathogenicity cont’

9. MycoplasmalpneumoniaE • Primary Atypical Pneumonia/ Walking pneumonia. • Incubation period: 1-3 wks • Transmission: airborne droplets of nasopharyngeal secretions, close contacts (families, military recruits).

10. PRIMARY ATYPICAL 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

11. Clinical Syndrome - M. pneumoniae • Incubation - 2-3 weeks • Fever, headache, malaise, persistent, dry, non-productive cough • Respiratory symptoms • Patchy bronchopneumonia • acute pharyngitis may be present • Organisms persist, Slow resolution, Rarely fatal

12. Epidemiology - M. pneumoniae • Occurs worldwide, No seasonal variation • Proportionally higher in summer and fall • Epidemics occur every 4-8 year • Spread by aerosol route (Confined populations). • Disease of the young (5-20 years), although all ages are at risk

13. Laboratory Diagnosis • Specimens – throat swabs, respiratory secretions. • Microscopy – • Highly pleomorphic, varying from small spherical shapes to longer branching filaments. 2. Gram negative, but better stained with Giemsa stain

14. Laboratory Diagnosis - M. pneumoniae • Culture (definitive diagnosis) • Sputum (usually scant) or throat washings • Isolation of Mycoplasma (Culture) – • Semi solid enriched medium containing 20% horse or human serum, yeast extract & DNA. Penicillium & Thallium acetate are selective agents. PPLO MEDIUM • Incubate aerobically for 7 -12 days with 5–10% CO2 at 35-37°C. • Colonies seen using hand lens or Dienes staining: alcoholic solution of methylene blue & azure

15. 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.

16. Fried egg colonies Dr Ekta,Microbiology, GMCA

17. Identification of Isolates • Growth Inhibition Test– inhibition of growth around discs impregnated with specific antisera. • Immuno-fluorescence on colonies transferred to glass slides. • Molecular diagnosis: PCR-based tests

18. Identification of Isolates • Serological diagnosis • Specific tests – IF, HAI 2. 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.

19. Treatment and PreventionM. pneumoniae • Macrolides are DOC (Azithromycin) • Other antibiotics: Tetracycline in adults (doxycycline) or erythromycin (children) • Newer fluoroquinolones (in adults) • Prevention • Avoid close contact

20. Ureaplasma urealyticum • M.hominis, M.genitaliulium, Ureaplasma: cause urogenital infections • Colonize female lower urogenital tract • Transmission: sexual contact/ to fetus during birth

21. Genital Infections • 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

22. Treatment: Macrolides: (azithromycin) for Ureaplasma & M.genitalium infections Doxycycline : M.hominis

23. 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.

24. POINTS TO BE REMEMBER • Mycoplasma • No cell wall • Pleomorphism • Fried egg colonies • Diene’s stain • Cold agglutination test • Cell culture contamination • Ureaplasma hydrolysis of urea • Primary atypical/ walking pneumonia • Genital infections

25. MCQ Q.1. Which of the following bacteria was named as Eaton agent • Acholeplasma • Mycoplasmahominis • Mycoplasmapneumoniae • Ureaplasmaurealyticum Q.2. Dienes method is used to examine colonies of • Bordetella • Burkholderia • Mycoplasma • Helicobacter

26. Q.3.Which of the following bacteria is/are associated with nongonococcalurethritis ? • Mycoplasmahominis • Ureaplasmaurealyticum • Chlamydia trachomatis • All of the above Q.4.Which is the causative agent of primary atypical pneumoniae • Influenza virus • Streptococcus Pneumoniae • Haemophilusinfluenzae • Mycoplasmapneumoniae

27. Q.5. Which of the following can hydrolyse urea • Mycoplasma • Acholeplasma • Ureaplasma • Escherichia Q.6. Which of the following bacteria is/are also named T strain ? • Mycoplasmapneumoniae • Mycoplasmahominis • Ureaplasmaurealyticum • Acholeplasma

28. Q.7.Postpartum fever due to Mycoplasmahominis is treated with • Penicillin G • A second generation Cephalosporins • Vancomycin • Tetracyclines/ doxycycline Q.8. Distinguishing feature of human mycoplasma species is: • Stain well with Giemsa, but not by Gram stain • Contain no bacterial peptidoglycan • Are not immunogenic because they mimic host cell membrane components • Cannot be cultivated in vitro

29. Q.9. which of the following tests can be used to identify Mycoplasmapneumoniae ? • Haem-adsorption test • Tetrazolium reduction test • Inhibition of growth by specific antisera • All of the above Q.10. Which of the following bacteria shows fried egg colonies on culture media ? • Helicobacter • Mycobacterium tuberculosis • Bordetella • Mycoplasma

30. ANSWERS OF MCQ Q.1- C Q.2- C Q.3- d Q.4- d Q.5- C Q.6- C Q.7- d Q.8- b Q.9- d Q.10- d