How can you differentiate between Nocardia and Mycobacterium?
The laboratory diagnosis is based on microscopy and culture isolation, but Nocardia can be mistaken for Mycobacterium, as they not only grow in specific media for mycobacteria, but also form partially acid-fast beaded branching filaments, similar to those formed by rapidly growing mycobacteria18.
What is present in the cell wall structure of Mycobacterium and Nocardia?
It is now generally accepted that the organisms belonging to the Corynebacteria–Mycobacteria–Nocardia group are covered by a complex cell envelope containing the inner plasma membrane (IM), the peptidoglycan–arabinogalactan complex, and the outer membrane (OM) that is covalently linked to the arabinogalactan (1, 2).
How do Mycobacterium and Nocardia react to acid-fast stain?
Mycobacterium and many Nocardia species are called acid-fast because during an acid-fast staining procedure they retain the primary dye carbol fuchsin despite decolorization with the powerful solvent acid-alcohol. Nearly all other genera of bacteria are nonacid-fast.
Does Nocardia have mycolic acid?
Diseases Caused by Nocardia Species Nocardia are gram-positive (of variable intensity) and have a branching, filamentous appearance. The mycolic acids make them variably acid fast, a fact that can be exploited for identification purposes by using weak acids for decolorization.
How does Mycobacterium look like?
The purple rod-shaped organism is a TB bacterium. This name, meaning ‘fungus-bacteria’ refers to shape of the bacillus when it grows in a laboratory: when seen through a microscope it forms heaps of small rods with protective layers around them, and thus looks like a fungus.
How can you distinguish Mycobacterium tuberculosis and Mycobacterium bovis?
Unlike Mycobacterium tuberculosis, which only causes human tuberculosis (TB), M. bovis is a zoonotic pathogen that infects humans and domestic animals. This infection causes bovine TB, thus posing a major economic and public health problem for the animal husbandry industry.
What are the characteristics of Mycobacterium tuberculosis?
Mycobacteria, such as M tuberculosis, are aerobic, non–spore-forming, nonmotile, facultative, curved intracellular rods measuring 0.2-0.5 μm by 2-4 μm.
What is unique about the cell wall of Mycobacterium?
The hallmark of mycobacteria is their unique abundance in lipid, constituting up to 40% of the dry weight of the tubercle bacillus3,4. The mycobacterial cell wall contains up to 60% of lipids, as compared with some 20% for the lipid-rich cell walls of Gram-negative microorganisms4.
What causes Nocardiosis?
Nocardiosis is a disease caused by bacteria found in soil and water. It can affect the lungs, brain, and skin. It is most common in people with weakened immune systems who have difficulty fighting off infections (for example, people with cancer or those taking certain medications such as steroids).
Does Nocardia produce spores?
Recently however, electron micrographs of aerial hyphae from Nocardia asteroides revealed chains of spores (Gordon and Mihm, 1958). This report confirms that N. asteroides is sporogenous and presents evidence that other species of Nocardia produce spores.
What type of bacteria is Nocardia?
Nocardiosis is a rare infection caused by the Nocardia asteroides bacterium. This type of bacteria can be found in the soil and water of regions around the world. People may become infected with this bacteria when they inhale it or when the bacteria enter an open wound.
Is Nocardia aerobic or anaerobic?
Nocardia are obligate aerobic, partially acid-fast, beaded, branching, gram-positive bacilli. The genus Nocardia has many species and an increasing number are recognized as causes of human disease.
What is the morphology of the Nocardia microbe?
Colonial morphology of the Nocardia is variable, from the smooth, almost bacterium-like appearance of N. farcinica, which turns orange with age, to a more chalky white appearance of most other species, depending on the presence of aerial hyphae.
Can a mycobacteria grow on a Nocardia media?
Nocardia spp. can grow on media for mycobacteria isolation (LJ and BBL MGIT™) and microscopy and colony morphology are very similar to some mycobacteria species. Seventeen patients (54.8%) were reported and treated for tuberculosis, but presented signs and symptoms of nocardiosis.
How to tell the color of a Nocardia colony?
Colony color may best be seen on the reverse when colonies are grown on translucent media (such as Sabouraud agar), as color may become obscured on the surface by the powdery aerial hyphae typically produced by members of this genu. Of the genera that are partially acid fast, only Nocardia species regularly produce aerial hyphae.
Is the Nocardia a non acid fast bacilli?
The Nocardia are often seen as partially acid-fast filamentous bacilli (showing both acid-fast and non-acid-fast Nocardia ). This acid fastness may be variable when staining colonies of Nocardia from cultured material.