Is Mycobacterium leprae aerobic or auxotrophic?
M.leprae is aerobic and auxotrophic meaning it requires a nutrient that the normal strain of Mycobacterium does not. These nutrients come from the host and is why it is parasitic. M. leprae's primary source for ATP is from the Krebs cycle. Ideal metabolism occurs at 33°C and a pH between 5.1 and 5.6.
What type of bacteria is M leprae?
M. leprae. Mycobacterium leprae, also known as Hansen’s bacillus spirilly, mostly found in warm tropical countries, is a bacterium that causes leprosy. It is an intracellular, pleomorphic, acid-fast, pathogenic bacterium. M. leprae is an aerobic bacillus (rod-shaped bacterium) surrounded by the characteristic waxy coating unique to mycobacteria.
What is Mycobacterium leprae (Hansen's bacillus spirilly)?
Mycobacterium leprae, also known as Hansen’s bacillus spirilly, mostly found in warm tropical countries, is a bacterium that causes leprosy. It is an intracellular, pleomorphic, acid-fast, pathogenic bacterium. M. leprae is an aerobic bacillus (rod-shaped bacterium) surrounded by the characteristic waxy coating unique to mycobacteria.
Why is Mycobacterium leprae difficult to culture?
Mycobacterium leprae. This can be used as a diagnostic test for the presence of bacilli in body lesions of suspected leprosy patients. The difficulty in culturing the organism appears to be because it is an obligate intracellular parasite that lacks many necessary genes for independent survival.
Is Mycobacterium a leprae Anaerobe?
Mycobacterium leprae is an aerobic, rod-shaped, Gram-positive bacterium in the Mycobacteriaceae family. Infections with this bacterium lead to leprosy.
Is Mycobacterium aerobic or anaerobic?
Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes.
Are mycobacteria aerobic?
Metabolism and morphology Mycobacteria are aerobic. They are bacillary in form, at least in most phases that have attracted human microbiological attention to date; they are straight or slightly curved rods between 0.2 and 0.6 µm wide and between 1.0 and 10 µm long.
Is M. leprae an obligate aerobe?
leprae, suggests that it has lost many of its metabolic capabilities, and is now an obligate parasite, dependent on its host for most of its nutritional needs.
Is Mycobacterium leprae Gram-positive or negative?
Gram-positive bacillusMycobacterium leprae is an acid-fast intracellular Gram-positive bacillus, which shows tropism for macrophages and Schwann cells.
Does Mycobacterium need oxygen?
Introduction. Mycobacterium tuberculosis is an obligate aerobe bacteria requiring oxygen in its metabolism processes.
Is Mycobacterium tuberculosis a facultative anaerobe?
M. tuberculosis is a tiny thin obligate aerobic (3 µm in length and 0.5 µm in width), acid-fast and a Gram-positive pathogen. As mentioned above, it can also be a facultative anaerobe.
What is aerobic bacteria with example?
Differentiate Between Aerobic and Anaerobic BacteriaAerobic BacteriaAnaerobic BacteriaIn a liquid culture, they come to the surface of the liquid medium.In a medium, these microorganisms, settle at the bottom of the medium.Examples: Lactobacillus, Nocardia, etc.Examples: Bacteroides, Clostridium, etc.8 more rows
Is Mycobacterium leprae acid-fast?
Mycobacterium leprae, first identified by Hansen in 1873, is a weakly acid-fast, rod-shaped bacterium.
Is Mycobacterium an obligate aerobe?
Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes.
How does Mycobacterium leprae reproduce?
Mycobacterium leprae will, like most bacteria, go through asexual (binary fission) reproduction as long as the conditions are favorable. If necessary, sexual reproduction will be used in unfavorable conditions. One of the main problems with Mycobacterium leprae is the slow growth rate.
What is the difference between Mycobacterium tuberculosis and Mycobacterium leprae?
Mycobacterium tuberculosis is cultivable; Myco- bacterium leprae is not. M leprae infects peripheral nerves; M tuberculosis does not. Untreated tuber- culosis has a high mortality; untreated leprosy has a high disability rate due to peripheral neuropathy.
Why is Mycobacterium tuberculosis aerobic?
The physiology of M. tuberculosis is highly aerobic and requires high levels of oxygen. Primarily a pathogen of the mammalian respiratory system, it infects the lungs....Mycobacterium tuberculosisFamily:MycobacteriaceaeGenus:MycobacteriumSpecies:M. tuberculosisBinomial name10 more rows
Is Mycobacterium tuberculosis a facultative anaerobe?
M. tuberculosis is a tiny thin obligate aerobic (3 µm in length and 0.5 µm in width), acid-fast and a Gram-positive pathogen. As mentioned above, it can also be a facultative anaerobe.
Is Mycobacterium avium aerobic?
avium had been rapidly shifted to anaerobic conditions, not slowly adapted. Thus, those increases occurred rapidly and under conditions of rapid onset of anaerobiosis. A comparison of the activities of glycine dehydrogenase and isocitrate lyase indicates that the level of their activities in aerobically grown M.
Does Mycobacterium tuberculosis need oxygen to survive?
Mycobacterium tuberculosis is a strict aerobe capable of prolonged survival in the absence of oxygen.
What is the binomial name for Mycobacterium leprae?
Hansen, 1874. The manifestation of Mycobacterium leprae ( leprosy) in human flesh as Tubercular leprosy. Mycobacterium leprae is a bacterium that causes leprosy, also known as " Hansen’s disease", which is a chronic infectious disease that damages the peripheral nerves and targets the skin, eyes, nose, ...
Where is M. leprae found?
The geographic occurrences of M. leprae include: Angola, Brazil, Central African Republic, the Democratic Republic of Congo, Federated States of Micronesia, India, Kiribati, Madagascar, Nepal, Republic of Marshall Islands, and the United Republic of Tanzania.
How big is M. leprae?
Optical microscopy shows M. leprae in clumps, rounded masses, or in groups of bacilli side by side, and ranging from 1–8 μm in length and 0.2–0.5 μm in diameter. The organism has been successfully grown on an artificial cell culture medium on a very limited basis by researcher Arvind Dhople. This can be used as a diagnostic test for the presence of bacilli in body lesions of suspected leprosy patients. The difficulty in culturing the organism appears to be because it is an obligate intracellular parasite that lacks many necessary genes for independent survival. The complex and unique cell wall that makes members of the genus Mycobacterium difficult to destroy is apparently also the reason for the extremely slow replication rate. Virulence factors include a waxy exterior coating, formed by the production of mycolic acids unique to Mycobacterium .
Why is mycobacterium replication so slow?
The complex and unique cell wall that makes members of the genus Mycobacterium difficult to destroy is apparently also the reason for the extremely slow replication rate. Virulence factors include a waxy exterior coating, formed by the production of mycolic acids unique to Mycobacterium .
How long have M. leprae and M. tuberculosis been separated?
The ancestors of M. leprae and M. tuberculosis have been estimated to have separated 36 million years ago.
How many genes are lost in M. leprae?
M. leprae has undergone a dramatic reduction in genome size with the loss of many genes. This genome reduction is not complete and numerous genes are still present as nonfunctional pseudogenes. Downsizing from a genome of 4.42 Mbp, such as that of M. tuberculosis, to one of 3.27 Mbp would account for the loss of some 1200 protein -coding sequences. Some evidence shows that many of the genes that were present in the genome of the common ancestor of M. leprae and M. tuberculosis have been lost in the M. leprae genome. 1500 genes are still common to both M. leprae and M. tuberculosis .
What is the preventive measure for M. leprae?
A preventive measure of M. leprae is to avoid close contact with infectious people who are untreated. Blindness, crippling of the hands and feet, and paralysis are all effects of nerve damage done by untreated M. leprae. Treatment does not reverse the nerve damage done, which is why it is recommended to get treated as soon as possible. The Bacillus Calmette–Guérin vaccine offers a variable amount of protection against leprosy in addition to its main target of tuberculosis.
Where does Mycobacterium leprae enter the body?
Now, Mycobacterium leprae can enter the body through the lungs or broken skin. Once inside the body, it goes for regions in which the temperature is lower than the rest of the body such as skin, peripheral nerves and mucosa of the upper respiratory tract. So, the bacteria goes for the Schwann cells of peripheral nerves.
How does the host respond to leprosy?
Now, the host responds to leprosy through cell mediated immunity via T- helper cells. These cells help the activity of other immune cells by releasing T cell cytokines, and there are two types of T- helper cells - Th1 and Th2.
What is the name of the rod-shaped bacteria that Hansen discovered?
Alexandru Duhaniuc. Mycobacterium leprae is a rod-shaped bacteria which was first discovered in 1873 by Hansen. Mycobacterium leprae is a non tuberculous mycobacteria and it causes a disease called leprosy, or Hansen disease. In US, the animal reservoir for Mycobacterium leprae are armadillos.
Can Mycobacterium leprae infect skin?
Additionally, Mycobacterium leprae can also infect skin macrophages. So, the bacteria is ingested by macrophages and wrapped up in a vesicle called a phagosome, which would normally merge with another intracellular organelle called a lysosome. Inside the phagolysosome, the bacteria would normally be destroyed.
Is Mycobacterium leprae acid fast?
Now, Mycobacterium leprae it’s an acid-fast bacillus which means it’s resistant to decolorization by acids and it has a high content of mycolic acid in its cell wall, which makes it waxy, hydrophobic and impermeable to routine stain such as Gram stain.
Does Mycobacterium leprae have phagolysosomal fusion?
Inside the phagolysosome, the bacteria would normally be destroyed. But, Mycobacterium leprae has the ability to inhibit the phagolysosomal fusion, which allows the bacteria to survive inside macrophages and replicate there. Now, the host responds to leprosy through cell mediated immunity via T- helper cells.
Where is the DNA of M. leprae found?
leprae was found in soil close to where people were infected with leprosy. Its ideal temperature is about 30-33oC. Clinical significance. Leprosy.
Where does leprosy live?
Natural habitats. This bacteria is believed to live in the soil.
How long does it take for leprosy to show?
It usually takes about 3 to 5 years for symptoms to appear after coming into contact with the leprosy-causing bacteria. Some people do not develop symptoms until 20 years later. There are three forms of the disease, with lepromatous being the most severe, tuberculoid, and borderline leprosy.
When was leprosy discovered?
General information. Leprosy is also known as Hansen’s disease, after the scientist who discovered M. leprae in 1873 . Leprosy has been around since ancient times, often surrounded by terrifying, negative stigmas and tales of leprosy patients being shunned as outcasts. Outbreaks of leprosy have affected, and panicked, people on every continent.
Is leprosy contagious?
Leprosy. Is an infectious disease that causes severe, disfiguring skin sores and nerve damage in the arms and legs. Leprosy is actually not that contagious. You can catch it only if you come into close and repeated contact with nose and mouth droplets from someone with untreated leprosy.
Can M. leprae be grown in artificial culture?
Obligate aerobic. M. leprae has never been grown in artificial culture, but will grow in the footpads of mice and in armadillos. The culture can take several weeks to mature. As one of the slowest growing bacteria known and its inability to grow independently, successful in vitro cultivation has never been achieved.
Is leprosy acid fast?
Acid-fast. It is a strongly acid-fast rod shaped organism with parallel sides and rounded ends. It occurs in large numbers in the lesions of lepromatous leprosy, chiefly in masses with the lepra cells, often grouped together like bundles of cigars or arranged in a palisade. Chains are never seen.
Classification
- Higher order taxa
Bacteria; Actinobacteria; Actinobacteria; Actinobacteridae; Actinomycetale; Corynebacterineae; Mycobacteriaceae
Description and Significance
- Mycobacterium leprae, also known as "Hansen's Bacillus", was discovered by Doctor Gerhard Armauer Hansen in 1873. Dr. Hansen discovered the bacteria in the nodules of leprosy patients and determined that it was the cause of the leprosy. The disease that M. leprae causes is referred to as leprosy or Hansen's Disease. Since M. leprae is the cause of leprosy it is pathogenic. Lepro…
Genome Structure
- The M. leprae genome project was sequenced in 2001 by the Sanger Institute. The sequence was found by employing automated DNA sequence analysis of selected cosmids and whole-genome clones. After the completion of this, the genome sequence was found to contain 3,268,203 base pairs (bp), and to have an average of G&C (Guanine and Cytosine) content of 57.8%. However, co…
Ecology
- M. leprae can be typically found in water, soil, or in the air. In fact the DNA from M. leprae has been discovered in several soil samples that are prone to the disease leprosy. But even though it can be found in soil, M. leprae is very selective when picking its hosts. Its ideal conditions are around 27-30°C. Most mammals do not have a body temperature of 33°C, so only a few species …
Interesting Feature
- History of Leprosy
Leprosy has been around humans since 1550 B.C. The ancient Egyptians were the first to record its presence on ancient papyrus scrolls. In 600 B.C. the ancient Indians also wrote about a disease similar to what we know as leprosy today. Historians believe that the disease was spread to Eur…
References
- 1) "Leprosy Today." World Health Organization. World Health Organization. 10 Oct 2007 2) National Center for Biotechnology Information. Mycobacterium leprae TNGenome Project Result. 6 November 2007 3) Herbs 2000. "Chaulmoogra" 5 December 2007 Brennan, J. T. Mycobacteria . In Encyclopedia of Microbiology (pp.312-327). a. Drugs.com Drug Information Online. (2007, Au…
Overview
Mycobacterium leprae is a bacterium that causes Hansen’s disease (leprosy), which is a chronic infectious disease that damages the peripheral nerves and targets the skin, eyes, nose, and muscles. It has also been known as the leprosy bacillus or Hansen's bacillus. Leprosy can occur at all ages from infancy to elderly, but is curable in which treatments can avert disabilities. It was discove…
Microbiology
M. leprae is an intracellular, pleomorphic, acid-fast, pathogenic bacterium. It is an aerobic bacillus (rod-shaped bacterium) with parallel sides and round ends, surrounded by the characteristic waxy coating unique to mycobacteria. In size and shape, it closely resembles Mycobacterium tuberculosis. This bacterium often occurs in large numbers within the lesions of lepromatous leprosy that are usually grouped together like bundles of cigars or arranged in a palisade. Due t…
Microscopy
Optical microscopy shows M. leprae in clumps, rounded masses, or in groups of bacilli side by side, and ranging from 1–8 μm in length and 0.2–0.5 μm in diameter. The organism has been successfully grown on an artificial cell culture medium on a very limited basis by researcher Arvind Dhople. This can be used as a diagnostic test for the presence of bacilli in body lesions of suspected lep…
Pathogenesis
The incubation period of M. leprae can range between 9 months and 20 years. It replicates intracellularly inside histiocytes and nerve cells and has two forms. One form is "tuberculoid," which induces a cell-mediated response that limits its growth. Through this form, M. leprae multiplies at the site of entry, usually the skin, invading and colonizing Schwann cells. The microbe then induces T-helpe…
Genome
Mycobacterium leprae has the longest doubling time (at 13 days of doubling time in the mouse footpad. ) of all known bacteria and has thwarted every effort at culture in the laboratory. Comparing the genome sequence of M. leprae with that of M. tuberculosis provides clear explanations for these properties, and reveals an extreme case of reductive evolution. Less than half of the genome contains functional genes. Gene deletion and decay appear to have eliminate…
Ancient Mycobacterium leprae
Almost complete sequences of M. leprae from medieval skeletons with osteological lesions suggestive of leprosy from different Europe geographic origins were obtained using DNA capture techniques and high-throughput sequencing. Ancient sequences were compared with those of modern strains from biopsies of leprosy patients representing diverse genotypes and geographic origins, giving new insights in the understanding of its evolution and course through history, phyl…
Evolution
The closest relative to M. leprae is M. lepromatosis. These species diverged 13.9 million years ago (95% highest posterior density 8.2 million years ago – 21.4 million years ago ) The most recent common ancestor of the extant M. leprae strains was calculated to have lived 3,607 years ago [95% highest posterior density 2204–5525 years ago]. The estimated substitution rate was 7.67 x 10 …
Symptoms of Mycobacterium leprae
The symptoms of M. leprae, also known as leprosy, are unattractive skin sores that are pale in color, lumps or bumps that do not go away after several weeks or months, nerve damage which can lead to complications with the ability to sense feeling in the arms and legs as well as muscle weakness. Symptoms usually take 3–5 years from being exposed to manifest within the body. Howe…