Is M tuberculosis gram positive?

Is M tuberculosis gram positive?

Basic Microbiology Mycobacteria are Gram-positive, catalase positive, non-motile, non-spore forming rod-shaped bacteria (0.2–0.6 μm wide and 1.0–10 μm long).

Why is Mycobacterium tuberculosis beaded?

Bead formation is dependent upon the composition and the concentration of the fuchsin dye used in the Ziehl-Neelsen staining procedure. Tubercle bacilli stained with the acetate dye show many beaded forms; with the hydrochloride they are absent or few in number.

What is M TB?

Mycobacterium tuberculosis (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid.

What medium is used to culture Mycobacterium tuberculosis?

Löwenstein–Jensen medium, more commonly known as LJ medium, is a growth medium specially used for culture of Mycobacterium species, notably Mycobacterium tuberculosis.

What is special about mycobacteria?

Mycobacteria are immobile, slow-growing rod-shaped, gram-positive bacteria with high genomic G+C content (61-71%). Due to their special staining characteristics under the microscope, which is mediated by mycolic acid in the cell wall, they are called acid-fast. This is also the reason for the hardiness of mycobacteria.

What is tuberculosis morphology?

Mycobacterium tuberculosis is a fairly large nonmotile rod-shaped bacterium distantly related to the Actinomycetes. Many non pathogenic mycobacteria are components of the normal flora of humans, found most often in dry and oily locales. The rods are 2-4 micrometers in length and 0.2-0.5 um in width.

Where is M. tuberculosis found?

Tuberculosis (TB) is an acute or chronic bacterial infection found most commonly in the lungs. The infection is spread like a cold, mainly through airborne droplets breathed into the air by a person infected with TB. The bacteria causes formation of small tissue masses called tubercles.

What is the most important virulence factor for M TB?

PDIM and PLG are major virulence factors of mycobacteria. PDIM and PGL are molecules required for bacterial duplication during the acute phase [33].