Summary

These notes cover Gram-positive acid-fast bacilli, including the genus Mycobacterium. They outline various tests for identification, different media for growth, and details on rapid versus slow growers. Information on specific Mycobacterium species, such as M. tuberculosis and M. leprae, is included.

Full Transcript

MIDTERM - BACTE LECTURE NOTES # 3 - prepared by: MAM LIGHT GRAM-POSITIVE ACID-FAST BACILLI – GENUS MYCOBACTERIUM  Aerobic, non-motile;  Slow growers and requires whole egg for growth  Difficult to stain but once stained difficult to decolorize due hydroxy m...

MIDTERM - BACTE LECTURE NOTES # 3 - prepared by: MAM LIGHT GRAM-POSITIVE ACID-FAST BACILLI – GENUS MYCOBACTERIUM  Aerobic, non-motile;  Slow growers and requires whole egg for growth  Difficult to stain but once stained difficult to decolorize due hydroxy methoxy acid / mycolic acid M. tuberculosis complex MOTT/ Mycobacterium other M. leprae than tuberculosis/ Runyon’s Classification M. tuberculosis _______________________ PHOTOCHROMOGENS  a.k.a Hansen’s disease M. bovis _____________________________ SCOTOCHROMOGENS  Causes LEPROSY M. africanum _________________________ NON-PHOTOCHROMOGENS  Non-culturable In vitro but viability can be M. microti & M. canetti – can infect RAPID GROWERS maintains using MICE FOOT PADS or FOOT those who are immunocompromised PADS of ARMADILLO  Under the microscope it forms the so-called Cigar Packet arrangement  Diagnosis is often made based on clinical symptoms SCREENING TEST: ACID FAST STAINING 1) Ziehl Neelsen _____________________________ 2) Kinyoun’s Method _________________________ DO CULTURE NON-SELECTIVE AGAR BASED SELECTIVE LIQUID MEDIA egg based media with malachite green, inhibits contaminating organism; clear media, easy with these are growth in 6-10 weeks examination of antibiotics non- colonies growth in conventional 10-12 days media Common Disadvantage: Lowenstein Jensen Media: ____________________________________________ Middlebrook 7H10 Gruft Bactec 12B, Petragnani- more inhibitory: ___________________________________________ with dextrose Modified Bactec 13A American Thoracic Society /ATS ______________________________________ Middlebrook 7H11 Lowenstein Septi-chek Dorset Egg Media with casein Jensen Middlebrook Wallenstein medium: _________________________________________________ hydrolysate Selective 7H9 Mitchison 7H11 Middlebrook 7H11 Mitchison Selective 7H11 IF THERE IS (+) GROWTH IN ANY OF THESE MEDIA, NEXT STEP IS TO DO SERIES OF BIOCHEMICAL TESTS TO IDENTIFY SPECIES BIOCHEMICAL TEST REQUIRED REAGENT (+) RESULT (-) RESULT POSITIVE NEGATIVE MEDIA CONTROL CONTROL pg. 1 1ST SEMESTER 2023-2024 MIDTERM - BACTE LECTURE NOTES # 3 - prepared by: MAM LIGHT NIACIN TEST Lowenstein Strip impregnated with YELLOW No color M. M. Jensen Media CYANOGEN BROMIDE change tuberculosis intracellulare NITRATE Sodium Nitrate After incubation we Initial (+) RED M. M. REDUCTION Broth add: (-) no color change tuberculosis intracellulare n-n -dimethyl-l- naphthylamine After adding zinc powder: sulfanilic acid (+) no color change (-) RED to confirm a (-) result we add: Use of Strip (+) Blue zinc dust/zinc powder IRON UPTAKE TEST Lowenstein No color x Jensen Media change ARYLSULFATASE Phenolphthalein 2N Sodium carbonate. M. fortuitum M. TEST media intracellulare Detection of rapid growers PYRAZINAMIDASE Pyrazinamidas 1% ferrous ammonium (+) red TEST e agar sulfate HEAT STABLE Tween 80 Heating of colonies at QUALITATIVE M. fortuitum M. CATALASE TEST Media 68 degC prior to the (+) ____________________ M. gordonae tuberculosis To detect heat labile addition of reagent is (-) ______________________ catalase required Mycobacterium like M. QUANTITATIVE tuberculosis (+) height of bubbling more than 45 mm (-) less than 45 mm TWEEN 80 Useful in the identification of M. kansasii ____________________ M. kansasii M. HYDROLYSIS TEST M. tuberculosis (+) in 10-20 days intracellulare (+) result: _____________________________ (-) result: no color change Indicator: _____________________________ TELLURITE For the identification of M. avium M. avium M. REDUCTION TEST (+) result: smooth, fine black precipitate (smoke like action) tuiberculosis (-) result:gray clumps (no smoke like action) SALT TOLERANCE For identification of rapid growers & M. triviale M. fortuitum M. gordonae TEST 5% NaCl (+) growth while (-) no growth T2H/ TCH May be done to differentiate M. tuberculosis and M. bovis M. bovis M. susceptibility (+) growth inhibition (no growth) tuberculosis Thiopene-2- (-) growth carboxylic hydrazide Growth in  To identify M. fortuitum -chelonae complex Mac Conkey agar without crystal violet NIACIN TEST NITRATE REDUCTION PYRAZINAMIDASE TWEEN 80 HYDROLYSIS HEAT STABLE CATALASE Mycobacterium tuberculosis  a.k.a Koch’s Bacillus or Tubercle Bacillus; obligate aerobe, gram (+) or gram neutral pg. 2 1ST SEMESTER 2023-2024 MIDTERM - BACTE LECTURE NOTES # 3 - prepared by: MAM LIGHT  Virulence Factors: (1) CORD FACTOR and (2) SULFATIDES _____________________________________________  With MUCH GRANULES, length is 1-4 u while diameter is 0.2 – 0.6  Produces “cauli flower like growth at 35 – 37 degC;  Causes Pulmonary TB; BCG vaccine / Bacillus Calmette Guerin __________________________________ Types of TB: (Primary, Secondary, MDR-TB – shows resistance to PRIMARY TB DRUGS), XDR-TB- shows resistance not only to primary but also to some 2nd line TB drugs POTT’s disease – TB of spine while MILIARY – disseminated TB, extrapulmonary PRIMARY TB DRUGS – RIPES – Rifampin-Isoniazid- Pyrazinamide-Ethambutol- Streptomycin 2ND LINE TB DRUGS – ofloxacin, kanamycin, ciprofloxacin DIAGNOSIS 1. Skin Testing – MANTOUX TEST – involves intradermal injection of PPD on the skin PPD (purified Protein Derivative) – protein extracted and purified from M. tuberculosis cell wall OT (old tuberculin) Von Pirquet _____________ (old tuberculin mixed with lanolin to produce ointment w/c is scratch onto the skin) 2. Chest X-Ray 3. Sputum exam – collect _______________in a day (1st ______________________, 2nd ______________________) 4. Culture – maintained for 8 wks / 2 months  CAULI FLOWER LIKE GROWTH – tan to buff, dry, rough, warty, granular 5. QUANTIFERON TB (ELISA) rapid and requires heparinized whole blood 6. GeneXpert – PCR Based NAAT, rapid and sensitive Mycobacterium bovis  _____________________________________________________________________________________________  ______________________________________________________________________________________________  Nitrate and Niacin Test __________________ Mycobacterium leprae a.k.a __________________________  Forms the so-called ____________________________________________________________  Non culturable on artificial media, but can be maintained in the lab using ________________________________________________________  Causes Leprosy MOT – prolong skin to skin contact with infected person, droplets from nose & mouth (inhalation)  Clin manifestation LEONINE FACE  Tuberculoid type /paucibacillary_____________________________________________________________________  Lepromatous type /multibacillary ____________________________________________________________________  Basis of diagnosis: _____________________________________________________Lepromin Test____________________________________  Specimen: TISSUE JUICE (earlobes, nasal scrapings) NON-TUBERCULOUS MYCOBACTERIA PHOTOCHROMOGENS  Mycobacterium kansasii – regarded as the # 2 NTM to cause TB in those with AIDS; a.k.a Cross Barred Bacillus  Mycobacterium marinum- can cause Fish Tank granuloma or _________________________________  Mycobacterium asiaticum, M. simiae , M. intermedium & M. novocastrense SCOTOCHROMOGENS  Mycobacterium szulgai - pulmonary disease, predominantly in middle-aged men; cervical adenitis; bursitis  Mycobacterium scrofulaceum - Cervical adenitis in children, bacteremia, pulmonary disease, skin infections  Mycobacterium gordonae / M. aquae __________________________________  M. xenopi - Primarily pulmonary infections in adults. ______________________colonies on CORN MEAL AGAR  M. flavescens , M. thermoresistible  M. interjectum - Unknown Potentially pathogenic Chronic lymphadenitis, pulmonary disease  Others: M. heckeshornense, M. tusciae, M. kubicae, M. cookie, M. hiberniae NON-PHOTOCHROMOGENS  M. avium complex - pulmonary infections in patients with preexisting pulmonary disease; cervical lymphadenitis; and disseminated disease (M. avium pathogenic – LADY WINDERMERE SYNDROME while M. intracellulare = Battey Bacillus)  M. terrae _____________________________ M. triviale - ___________________________  M. gastri , M. ulcerans - mycobacteriosis, also referred to as Buruli ulcer, biochemically inert  M. malmoense M. genovense -Disseminated disease in patients with AIDS  , M. haemophilum , Others: M. heidelbergense; M. simiae; M. shimoidei RAPID GROWERS  M. abscessus subsp. Abscessus - Disseminated disease, primarily in immunocompromised individuals; skin and soft tissue infections; pulmonary infections; postoperative infections  M. fortuitum - Postoperative infections in breast augmentation and median sternotomy; skin and soft tissue infections; pulmonary infections, usually single. localized lesions. Central nervous system (CNS) disease is rare but has high morbidity and mortality  M. chelonei - Skin and soft tissue infections, postoperative wound infections, keratitis  M. phlei – breadcrumbs growth on LJ medium  Other: M. smegmatis – Urine AFB + Biochemical tests to speciate Mycobacterium pg. 3 1ST SEMESTER 2023-2024 MIDTERM - BACTE LECTURE NOTES # 3 - prepared by: MAM LIGHT Tests Mycobacterium tuberculosis Mycobacterium bovis Niacin test + - Nitrate Reduction Test + - Heat Stable Catalase test - - Tween 80 Hydrolysis Test V - Arylsulfatase Test (3days) - - Iron Uptake Test - - Pyrazinamidase Test + - Tests M. kansasii M. marinum M. simiae M. asiaticum Niacin test - V + - Nitrate Reduction Test + - - - Heat Stable Catalase test + - + + Tween 80 Hydrolysis Test + + Slow + + Arylsulfatase Test (3days) - V - - Iron Uptake Test - - - - Pyrazinamidase Test - + + - Tests M. scrofulaceum M. szulgai M. gordonae M. thermoresistible M. flavescens Niacin test - - - - - Nitrate Reduction Test - + - - + Heat Stable Catalase test + + + + + Tween 80 Hydrolysis Test - Slow + + + + Arylsulfatase Test (3days) - - - - - Iron Uptake Test - - - - - Pyrazinamidase Test V - - NA + Tests M. Avium – Intracellulare M. terrae – triviale M. malmoense M. haemophilum M. gastri Complex complex Niacin test - - - - - Nitrate Reduction Test - + - - - Heat Stable Catalase test + + + - - Tween 80 Hydrolysis Test - + + - + Arylsulfatase Test (3days) - - - - - Iron Uptake Test - - - - - Pyrazinamidase Test + V + + - Tests M. fortuitum M. chelonei M. phlei M. smegmatis Niacin test - - - - Nitrate Reduction Test + - + + Heat Stable Catalase test + + + + Tween 80 Hydrolysis Test V - + + Arylsulfatase Test (3days) + + - - Iron Uptake Test + - + + Pyrazinamidase Test + + - NA DO NOT ANYMORE READ THE MYCOBACTERIUM CHAPTER in the BOOK BY MAHON pg. 4 1ST SEMESTER 2023-2024

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