Biochemical Characteristics of Mycobacterium tuberculosis

Biochemical Characteristics of Mycobacterium tuberculosis

Some of the biochemical test results are as follows: S.N. Biochemical Test Results 1 5% NaCl Tolerance Negative (-ve) 2 68°C Catalase Test Negative (-ve) 3 Acid Phosphatase Negative (-ve) 4 Amidase Test Positive (+ve) 5 Arylsulphatase Test Negative (-ve) 6 Growth on P-Nitrobenzoic Acid Negative (-ve) 7 Growth on TCH (10mg/ml) Positive (+ve) 8 Iron Uptake Negative (-ve) 9 …

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Cultural Characteristics of Mycobacterium tuberculosis

Cultural Characteristics of Mycobacterium tuberculosis

Culture is the gold standard for laboratory confirmation of Tuberculosis. Growing bacteria are required to perform drug-susceptibility testing and genotyping. In the Lowenstein-Jensen (LJ) medium It is an egg-based medium and growth is quite slow. It takes 6-8 weeks to get visual colonies on this type of media. Colonies are non-pigmented, dry, rough, raised, irregular with a wrinkled surface They …

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Middlebrook Agar

Middlebrook Agar

Middlebrook Agar There are many culture media that have been devised for the cultivation of mycobacteria over the years. The early ones were egg-based formulations which included Lowenstein-Jensen Medium and Petragnani Medium. Later, Dubos and Middlebrook developed various formulations containing oleic acid and albumin as key ingredients, which protect Mycobacterium from toxic agents, helping for the growth of tubercle bacilli. …

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Lowenstein Jensen (LJ) Media

Result Interpretation of Lowenstein Jensen (LJ) Media

Lowenstein Jensen (LJ) Media Lowenstein Jensen Medium (LJ Medium) is a selective medium that is commonly used for the cultivation and isolation of Mycobacterium, specifically Mycobacterium tuberculosis from clinical specimens. LJ medium was originally formulated by Lowenstein who incorporated congo red and malachite green to inhibit unwanted bacteria. The present formulation comprises of a glycerated egg-based medium and is based upon Jensen’s modification. …

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Biochemical Test of Mycobacterium tuberculosis

Biochemical Test of Mycobacterium tuberculosis Basic Characteristics Properties (Mycobacterium tuberculosis) 5 % NaCl Tolerance Negative (-ve) 68°C Catalase Test Negative (-ve) Acid Fast Stain Positive (-ve) Acid Phosphatase Negative (-ve) Amidase Test Positive (-ve) Arylsulphatase Test Negative (-ve) Growth at 22°C Negative (-ve) Growth at 25°C Negative (-ve) Growth at 42°C Negative (-ve) Growth at 25°C Negative (-ve) Growth on …

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Pathogenesis and Clinical Manifestations of Mycobacterium leprae

Pathogenesis and Clinical Manifestations of Mycobacterium leprae

Pathogenesis of Mycobacterium leprae M. leprae is an acid-fast, gram-positive obligate intracellular bacillus that shows tropism for cells of the reticuloendothelial system and peripheral nervous system (notably Schwann cells). Organisms may be acquired by the susceptible host usually through respiratory system or by way of skin to skin contact (between exudates of a leprosy patient’s skin lesions and the abraded skin …

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Laboratory diagnosis of Leprosy caused by Mycobacterium leprae

Laboratory diagnosis of Leprosy caused by Mycobacterium leprae

Laboratory diagnosis of Leprosy caused by Mycobacterium leprae Specimen Skin biopsies, nasal discharges, scrapings from the nasal mucosa and slit-skin smears which are prepared by making superficial incisions in the skin, scraping out some tissue fluid and cells. Skin smears The skin smears are collected from the leprous lesions, such as nodules, thick papules, and areas of infiltration. In cases …

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Laboratory diagnosis, treatment and prevention of Tuberculosis

Laboratory diagnosis, treatment and prevention of Tuberculosis

Laboratory diagnosis of Tuberculosis caused by Mycobacterium tuberculosis Specimen and processing sputum, bronchial washings, brushings or biopsies or early morning gastric aspirates, Cerebospinal Fluid (CSF), urine Specimens from sputum and other nonsterile sites should be liquefied with N-acetyl-L-cysteine decontaminated with NaOH (kills many other bacteria and fungi), neutralized with buffer, and concentrated by centrifugation. Specimens from sterile sites, such as …

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Pathogenesis and Clinical manifestation of Mycobacterium tuberculosis

Pathogenesis and Clinical manifestation of Mycobacterium tuberculosis

Virulence factors of Mycobacterium tuberculosis A. Mycolic acid and Lipoarabinomannan (LAM) Waxy layer that protects the bacteria from many host factors and also to many antibiotics including beta lactamases. Muramyl dipeptide (from peptidoglycan) complexed with mycolic acids can cause granuloma formation, phospholipids induce caseous necrosis. LAM is structurally and functionally related to the O antigenic lipopolysaccharides of other bacteria. Biological …

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Habitat and Morphology of Mycobacterium tuberculosis

Habitat and Morphology of Mycobacterium tuberculosis

Habitat and Morphology of Mycobacterium tuberculosis Habitat Human is only the know reservoir. Usually found in the lungs but can also live in any part of the body. They may be obligate pathogen, facultative or opportunistic pathogens or free living. Usually infect the mono-nuclear phagocytes. Can also be infected by the consumption of unpasteurized milk. Can survive for weeks in …

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