Legionella+Mycoplasma+Atypical Pneumonia

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Legionella+Mycoplasma+Atypical Pneumonia

  1. 1. LEGIONELLA MYCOPLASMA ATYPICAL PNEUMONIA Dr Kamran Afzal Classified Microbiologist
  2. 2. LEGIONELLA
  3. 3. TAXONOMY <ul><li>Domain : Eubacteria </li></ul><ul><li>Division : Proteobacteria </li></ul><ul><li>Family : Legionellaceae </li></ul><ul><li>Genus : Legionella </li></ul><ul><li>Species : L. pneumophila L. pasculeii </li></ul><ul><li>L. fraseri </li></ul><ul><ul><li>41 species, 3 sub-species and 60 serogroups </li></ul></ul>
  4. 4. Legionella pneumophila <ul><li>Gram – rods (weak) </li></ul><ul><li>0.3 - 0.9 μm X 1- 50 μm with pointed ends, wrinkled surface </li></ul><ul><li>Motile with polar / sub-polar flagella, pili, fimbriae </li></ul><ul><li>Strict aerobe </li></ul><ul><li>Nutritionally fastidious </li></ul><ul><ul><li>L-cysteine and ferric salts required </li></ul></ul><ul><li>Non-sporing, motile </li></ul>
  5. 5. EPIDEMIOLOGY <ul><li>1-4 % of all Pneumonias </li></ul><ul><li>Male preponderance </li></ul><ul><li>High summer incidence </li></ul><ul><li>Can cause community outbreak at large scale </li></ul><ul><li>Predisposing factors </li></ul><ul><ul><li>Smoking / Alcohol </li></ul></ul><ul><ul><li>Increased age </li></ul></ul><ul><ul><li>Underlying disease </li></ul></ul><ul><ul><ul><li>Lymphoma, leukemia, CCF, pulmonary disease </li></ul></ul></ul><ul><ul><li>Immuno-compromised status </li></ul></ul><ul><ul><ul><li>AIDS, T Cell dysfunctions </li></ul></ul></ul>
  6. 6. HISTORICAL PERSPECTIVE <ul><li>July 1976, American Legion Convention in Philadelphia, Pennsylvania </li></ul><ul><li>184 Legionnaires’ developed pneumonia </li></ul><ul><li>29 Legionnaires’ and 5 others staying in the same hotel died of illness </li></ul>
  7. 7. HABITAT <ul><li>Do not occur as commensal flora in man </li></ul><ul><li>No man to man transmission </li></ul><ul><li>Thermally heated bodies of water </li></ul><ul><ul><li>Hotels and hospitals </li></ul></ul><ul><li>Gain entry into cooling towers of large buildings and evaporative condensers of </li></ul><ul><ul><li>A/Cs, humidifiers, nebulizers </li></ul></ul>
  8. 11. LEGIONNAIRES’ DISEASE <ul><li>Incubation period : 2-10 days </li></ul><ul><li>Case fatality ratio : 0-20 % </li></ul><ul><li>Clinical syndrome : Pneumonia </li></ul><ul><li>Local Symptoms : High fever, cough, headache, chest pain, nausea, malaise, dyspnea and haemoptysis </li></ul><ul><li>Systemic Symptoms: Disorientation, confusion, nausea, vomiting, diarrhea and renal insufficiency </li></ul><ul><li>PONTIAC FEVER : A brief and slow febrile flu-like illness, does not cause death </li></ul>
  9. 14. LABORATORY DIAGNOSIS <ul><li>Samples </li></ul><ul><ul><li>Sputum </li></ul></ul><ul><ul><li>Lung biopsy material </li></ul></ul><ul><ul><li>Pleural fluid </li></ul></ul><ul><ul><li>Bronchial washings </li></ul></ul><ul><ul><li>Blood </li></ul></ul><ul><ul><li>Environmental samples (water) </li></ul></ul><ul><ul><li>Samples can be incubated at 60 0 C x 30 min </li></ul></ul><ul><li>Inoculated on BCYE Agar </li></ul>
  10. 15. CULTURAL CHARACTERISTICS <ul><li>Strict aerobe </li></ul><ul><li>37 0 C (30 – 60 0 C) X 10-14 days </li></ul><ul><li>L-cysteine and Iron required </li></ul><ul><li>Does not grow on ordinary culture media </li></ul><ul><li>Grows on </li></ul><ul><ul><li>Buffered Charcoal Yeast Extract Agar (BCYE) </li></ul></ul><ul><ul><li>Tyrosine BYE Agar </li></ul></ul><ul><ul><li>Feeley Gorman Agar </li></ul></ul>
  11. 16. COLONY APPEARANCE <ul><li>BCYE Agar </li></ul><ul><ul><li>Circular, low convex, smooth glistening surface, crenated edge, soft consistency, gray or gray/blue colour </li></ul></ul><ul><li>Fluorescence under UV light </li></ul><ul><ul><li>L. pneumophila colony does not produce fluorescence </li></ul></ul><ul><li>FG Agar </li></ul><ul><ul><li>Produce diffusible brown pigment </li></ul></ul><ul><li>Produce opacity around colonies on Egg Yolk medium with clearing beyond the zone of opacity </li></ul>
  12. 17. BIOCHEMICAL REACTIONS <ul><li>Does not ferment routine sugars </li></ul><ul><li>Hydrolyze </li></ul><ul><ul><li>starch </li></ul></ul><ul><ul><li>hippurate </li></ul></ul><ul><ul><li>gelatin </li></ul></ul><ul><li>Catalase + </li></ul><ul><li>Oxidase + </li></ul>
  13. 18. <ul><li>Immunoassays </li></ul><ul><ul><li>ELISA </li></ul></ul><ul><ul><li>RIA </li></ul></ul><ul><ul><li>Latex agglutination </li></ul></ul><ul><li>Direct detection </li></ul><ul><ul><li>DFAT </li></ul></ul><ul><ul><li>Silver impregnation </li></ul></ul><ul><li>Serology </li></ul><ul><ul><li>IFAT </li></ul></ul><ul><li>PCR </li></ul>
  14. 19. TREATMENT <ul><li>Erythromycin High dose I/V Macrolides </li></ul><ul><li>Azithromycin </li></ul><ul><li>Rifampicin </li></ul><ul><li>Fluoroquinolones </li></ul><ul><li>Supportive therapy </li></ul><ul><ul><li>Ventilation, renal dialysis, re-hydration, correction of electrolyte imbalance </li></ul></ul><ul><li>Control measures </li></ul><ul><ul><li>Chlorination of water with intermittent temperature increase to 60 0 C </li></ul></ul>
  15. 20. MYCOPLASMA
  16. 22. DISEASES
  17. 23. Differentiation of Species <ul><li>M. pneumoniae - glucose </li></ul><ul><li>M. hominis - arginine </li></ul><ul><li>U. urealyticum - urea </li></ul><ul><li>M. genitalium - difficult to culture </li></ul>
  18. 24. MORPHOLOGY <ul><li>Smallest free-living bacteria (0.2 - 0.8 µ m) </li></ul><ul><li>Small genome size </li></ul><ul><li>Strict aerobe </li></ul><ul><li>Lack a cell wall </li></ul><ul><li>Grow slowly by binary fission </li></ul><ul><li>“ Fried egg” colonies </li></ul>
  19. 25. “ Fried Egg” Colonies of Mycoplasma M. pneumoniae colonies have a granular appearance
  20. 27. Can be part of normal flora <ul><li>They reside extracellularly in the respiratory and urogenital tracts and rarely penetrate the sub-mucosa, except in the case of immunosuppression or instrumentation, when they may invade the bloodstream and disseminate to numerous organs and tissues </li></ul>
  21. 28. Mycoplasma are cell wall deficient <ul><li>Cross-section of Mycoplasma bacteria </li></ul>
  22. 29. PATHOGENESIS <ul><li>Adherence </li></ul><ul><ul><li>P1 pili </li></ul></ul><ul><ul><li>Movement of cilia ceases </li></ul></ul><ul><ul><li>Clearance mechanism stops </li></ul></ul><ul><li>Toxic metabolic products </li></ul><ul><ul><li>Peroxide and superoxide </li></ul></ul><ul><li>Immuno-pathogenesis </li></ul><ul><ul><li>Activate macrophages </li></ul></ul><ul><ul><li>Stimulate cytokine production </li></ul></ul>
  23. 31. CLINICAL MANIFESTATIONS <ul><li>Tracheo-bronchitis </li></ul><ul><ul><li>70-80% of infections </li></ul></ul><ul><li>Pneumonia </li></ul><ul><ul><li>Approximately 10% of all atypical pneumonias </li></ul></ul><ul><ul><ul><li>“ Primary atypical pneumonia” </li></ul></ul></ul><ul><ul><ul><li>Mild disease but long duration </li></ul></ul></ul>
  24. 32. <ul><li>Incubation 2-3 weeks </li></ul><ul><li>Persistent non-productive cough </li></ul><ul><li>Radiological signs precede symptoms </li></ul><ul><li>Slow resolution </li></ul><ul><ul><li>Rarely fatal </li></ul></ul>
  25. 33. LABORATORY DIAGNOSIS <ul><li>Microscopy </li></ul><ul><ul><li>Difficult to stain </li></ul></ul><ul><li>Immunochromatography </li></ul><ul><li>Immunofluorescence </li></ul><ul><li>Culture (definitive diagnosis) </li></ul><ul><ul><li>Sputum (usually scant) or throat washings </li></ul></ul><ul><ul><ul><li>May take 2-3 weeks </li></ul></ul></ul><ul><li>Molecular diagnosis </li></ul><ul><ul><li>PCR-based tests </li></ul></ul><ul><ul><ul><li>Rapid, sensitive and specific </li></ul></ul></ul>
  26. 34. <ul><li>Serology </li></ul><ul><ul><li>ELISA </li></ul></ul><ul><ul><li>Complement fixation </li></ul></ul><ul><ul><ul><li>May take 4-6 weeks </li></ul></ul></ul><ul><ul><ul><li>Fourfold rise in titer </li></ul></ul></ul><ul><ul><li>Cold agglutinins (4 0 C) </li></ul></ul><ul><ul><ul><li>1/3 - 2/3 of patients </li></ul></ul></ul><ul><ul><ul><li>Appear earlier </li></ul></ul></ul><ul><ul><ul><li>Non-specific </li></ul></ul></ul><ul><ul><ul><li>Presumptive diagnosis </li></ul></ul></ul>
  27. 35. Culturing Mycoplasma <ul><li>Mycoplasma can be cultured on liquid or solid media </li></ul><ul><ul><li>PPLO Broth enriched with 20% horse or human serum </li></ul></ul><ul><li>Grows optimally at 35 - 37 0 C up to 3 weeks </li></ul><ul><li>The colonies appear as fried egg </li></ul>
  28. 37. TREATMENT AND PREVENTION <ul><li>Treatment </li></ul><ul><ul><li>Tetracycline or erythromycin </li></ul></ul><ul><ul><li>Newer fluoroquinolones </li></ul></ul><ul><ul><li>They are relatively resistant to pencillins and Cephalosporins </li></ul></ul><ul><li>Prevention </li></ul><ul><ul><li>Avoid close contact </li></ul></ul><ul><ul><li>No vaccine </li></ul></ul>
  29. 38. ATYPICAL PNEUMONIA
  30. 39. DEFINITION <ul><li>Pneumonia is defined as inflammation of lung parenchyma </li></ul><ul><ul><li>During the process of inflammation of alveoli there occurs inflammatory exudate that fill up air spaces and result in consolidation of lung </li></ul></ul>
  31. 40. GROSS MANIFESTATIONS LOBAR PNEUMONIA BRONCHOPNEUMONIA INTERSTITIAL
  32. 41. ATYPICAL PNEUMONIA <ul><li>Atypical pneumonia is caused by atypical bacteria that do not stain with Gram stain or do not fit in any category like in virus or bacteria </li></ul><ul><li>The inflammation is confined to interstitial spaces between alveoli </li></ul><ul><li>Radiologically gives appearance of reticulonodular pattern </li></ul><ul><li>Linear thread like opacities in lungs </li></ul>
  33. 43. Not prominent Prominent (myalgia, fatigue, N/V, diarrhea) Extra-pulmonary symptoms Purulent Scanty Sputum Productive cough Dry cough Cough Abrupt Gradual Onset S. pneumoniae , H. influenzae , K. pneumoniae , mixed aerobic and anaerobic oral flora M. pneumoniae , L. pneumophilia, C. pneumophilla, viruses, protozoa and fungi Etiology TYPICAL PNEUMONIA ATYPICAL PNEUMONIA
  34. 44. ROUTES OF INFECTION <ul><li>Microaspiration </li></ul><ul><li>Gross Aspiration </li></ul><ul><li>Aerosolization / inhalation </li></ul><ul><li>Hematogenous route </li></ul><ul><li>Contiguous spread </li></ul>
  35. 45. INVESTIGATIONS <ul><li>Total and differential blood count </li></ul><ul><li>Blood, urine, sputum -> Culture/sensitivity </li></ul><ul><li>Gram staining/ZN stain for AFB </li></ul><ul><li>CRP </li></ul><ul><li>Serological investigations </li></ul><ul><li>Antigen detection in sputum or urine by </li></ul><ul><ul><li>Fluorescent methods, Immunoelectrophoresis, Latex agglutination, ELISA </li></ul></ul><ul><li>Radiology -> CXR, MRI and CT scan </li></ul><ul><li>Fiberoptic bronchoscopy with bronchial washing/ brushing /biopsy -> Histopathology </li></ul><ul><li>Molecular techniques </li></ul>
  36. 46. Serology <ul><li>By serological methods using acute and convalescent sera </li></ul><ul><li>Significantly raised titer or rising titer of antibodies give clues to diagnosis </li></ul>
  37. 47. Specific Serological Tests <ul><li>Legionella pneumophila </li></ul><ul><ul><li>Rapid microagglutination test </li></ul></ul><ul><ul><li>Test for Legionella antigen in the urine </li></ul></ul><ul><li>Mycoplasma pneumoniae </li></ul><ul><ul><li>Complement fixation test </li></ul></ul><ul><ul><li>IgM by latex agglutination or ELISA </li></ul></ul><ul><ul><li>Cold agglutinin test </li></ul></ul>
  38. 48. <ul><li>Chlamydia </li></ul><ul><ul><li>Microimmunofluorescence </li></ul></ul><ul><ul><li>ELISA </li></ul></ul><ul><li>Coxiella burnetii </li></ul><ul><ul><li>Complement fixation test </li></ul></ul><ul><li>Serologic tests </li></ul><ul><ul><li>A four fold or greater rise in titer is confirmatory of an acute infection </li></ul></ul>
  39. 49. Histopathology <ul><li>White spaces are alveolar spaces and are empty and clear </li></ul><ul><li>But surrounded by swollen interstitial tissue infiltrated with inflammatory cells, typical of interstitial pneumonia </li></ul>
  40. 50. <ul><li>Thread like linear striations extending in the lungs forming sort of a network </li></ul><ul><li>Very small patchy spots or nodules over or along these lines giving reticulo-nodular appearance -> Atypical or viral pneumonias </li></ul>Radiology
  41. 51. COMPLICATIONS <ul><li>Parapneumonic effusions </li></ul><ul><li>Septic arthritis </li></ul><ul><li>Endocarditis </li></ul><ul><li>Pericarditis </li></ul><ul><li>Respiratory failure </li></ul><ul><li>Mental symptoms </li></ul>

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