Mycobacterium pls ayoko na

• Characteristics of Mycobacterium

  • slender and slightly curved
  • non motile
  • slow growers - takes weeks to culture or create mature colonies except: M. fortuitum and M. chelonei
  • Cell wall: high lipid content and mycolic acid
  • Carbol fuschin of Kinyoun have a high phenolic compund
  • Resist decolorization - AFB
  • Much granules - M. tuberculosis
• Mycobacterium 3 groups:

  1. M. tuberculosis complex - causing TB
  2. M.O.T.T - mycobacterium other than tuberculosis
  3. M. leprae - Hansens disease
• M. tuberculosis

  Characteristics:

  • Robert koch in 1882
  • obligate aerobe or strict aerobes
  • Requires CO2 for growth (5-10%)
• M. tuberculosis

  Virulence factor:

  • Cord factor and sulfatides: sticky response
• M. tuberculosis - GRAM STAIN

  • Qualify specimen (Barlett's classification)

  - Sputum for 3 consecutive days

  - we can differentiate saliva from sputum

  • More than 10 epithelial cells with less than 25 polymorphonuclear cells = SALIVA - REJECT
  • Less than 1o epithelial cells with more than 25 polymorphonuclear cells = SPUTUM - ACCEPT
• SPECIMEN of Mycobacterium tuberculosis

  • Sputum
  • Secretions obtained by bronchoscopy
  • Blood - once the t0 became systemic
  • CSF - observe pellicle of web like clot
• Fite Fracos - hematoxylin instead of methyelen blue as counterstain
• Auramine rhodaminr fluorochrome stain (Truants)

  • more sensitive than carbon fuschin stains
  • bright, yellow orange bacilli against dark bg
• Spenglers

  • for colorblind individuals
• Pappenheims

  • MTb: Red
  • M. segmantis: blue
• Baumgartens

  • MTb : blue
  • M. leprae : Red

  AFB smear size - coiling by 2cm by 3cm
• Culture of mycobacterium requires increased protein
• AGAR BASED

  • Dubois Oleic Acid Albumin Medium
  • Mitchison medium
  • Middlebrook 7H10 - 7H11 - anti susceptibility test
• EGG BASED

  • Inhibitor: malachite green
  • Petragnani medium: used for heavily contaminated specimen
  • Lowenstein Jensen medium
  • American thoracic society
  • Dorset egg medium
• Lowenstein Jensen Medium

  Colonies

  • tan to buff
  • dry, rough, warty, and granular
  • resembles: cauliflower
  • culture maintained for: 8 weeks to 2 months
• Anti TB Agents [PRIMARY]

  • Rifampicin
  • Isoniazid
  • Pyrazinamide
  • Ethambutol
  • Streptomycin
• Anti TB Agents [SECONDARY]

  • Capreomycin
  • Cyclosrine
  • Ciprofloxacin
  • Ofloxacin
  • Kanamycin
  • Ethionamide
  • Rifambutin
• Niacin Test

  • one of the most important test
  • niacin + niacin ribonucleotide + aniline dye + cyanogrn bromide
  • (+) : yellow Mtb
  • (-) : no color change: M. bovis
• Catalase test

  • Best at 68 C
  • Medium: Tween 80
  • Reagent: 30% H2O2
  • (+): 45mm height gas bubbles
  • (-): no bubbles: M. kansasii
• Nitrate reduction test

  • Nitroreductase enzyme reduces nitrate to nitrite
  • HCL + sulfamamide + n napthtylethylene diamine
  • (+): pink to red
  • (-): no color change
• Tween 80 HOH

  • (+): Red M. kansasii
  • (-): no red M. avium
• Tellurite Reduction Test

  • Tellurite: black metallic tellurium after 3-4 days
  • (+): smooth black precipitates
  • (-): gray clumps
• Aryl Sulfatase Test

  • for detection of rapid growers
  • (+): pink to red color