| Mycobacterium tuberculosis was observed by Robert | | | | from most other mycobacteria by the production of |
| Koch in 1882, who discovered the staining technique | | | | niacin. |
| to see the bacterium. | | | | Mycobacterium tuberculosis is a Gram positive aerobic |
| In 1943, Selman A Waksman found the antibiotic | | | | mycobacterium that divides every 16-20 hours. This is |
| effective against Mycobacterium tuberculosis. | | | | extremely slow as compared to other bacteria which |
| Streptomycin purified from streptomyces grieseus | | | | tend to have division times measured in minutes(for |
| was administered to human in 1944. | | | | example Ecoli can divide roughly every 20 minute.) |
| Drug resistance in TB occurred as a result of tubercle | | | | Mycobacterium tuberculosis are grown on lowenstein |
| bacillus mutations. Soon the resistant mutants | | | | jensen media. Middlebrook media are used for faster |
| appeared, prooving the antibiotic therapy | | | | culture. |
| unsuccessful. Therefore combination of drugs were | | | | Bacteria can takes weeks to grow on culture media. |
| used to solve the problem of antibiotic resisitance. | | | | The Polymerase chain reaction is the rapid method |
| Multidrug reisistant tuberculosis-- MDR TB is TB that is | | | | which provides results within hours from specimen of |
| resisitant to atleast two of the best anti TB drugs, | | | | the patients. |
| isoniazed and rifamycin which are called first line | | | | TB refers only to disease caused by Mycobacterium |
| drugs. | | | | tuberculosis. |
| Extensively drug resistant TB is defined as TB which | | | | Similar disease ocassionally result from M.bovis,M |
| is resistant to isoniazed and rifamycin plus resisitant | | | | africanum, M.microti. |
| to any fluoroquinolone and atleast one of three | | | | TB of tonsils, lymph node, abdominal organs, bones |
| injectable second line drugs(amikacin, kanamycin or | | | | and joints was once commonly caused by ingestion |
| capreomycin. | | | | of milk infected with M. bovis but such infection is |
| MDR-TB varies from patients to patients. | | | | largely eradicated in developed countries by |
| Antibiotics such as para-aminosalicyclic acid and | | | | slaughtering cows that test positive. |
| streptomycin have been in use for more than 50 | | | | Cell wall of Mycobacterium tuberculosis contains |
| years. | | | | peptidoglycan and complex lipids. 60% of the cell wall |
| Patients are required to take upto 15 pills a day, plus | | | | is lipid. The lipid fraction consisit of mycolic acid, cord |
| daily injections, for atleast six months. | | | | factor and wax D. |
| Medical treatment is lengthy and protection through | | | | Mycolic acid are hydrophobic molecules that affect |
| vaccination is today, as before is insufficient. | | | | permeability properties at cell surface. |
| Every year nearly two million people die from the | | | | Mycolic acid prevent attack of the Mycobacteria by |
| disease. The bacterium that cause TB are spread in | | | | cationic proteins, lysozyme and oxygen radicals in |
| airborne droplets when people with disease cough or | | | | phagocytic granule. |
| sneeze. | | | | Cord factor is toxic to mammalian cells. |
| TB is considered lung disease however it can attack | | | | Lipids cause resistance to many antibiotics and killing |
| other parts of body such as kidneys or the brain. | | | | by acidic and alkaline compounds and resistance to |
| TB is highly contagious and is spread through air. | | | | lethal oxidation and survival inside the macrophages. |
| Mycobacterium tuberculosis is resisitant to | | | | Mycolic acid give rigid cell shape to the bacteria. |
| disinfectants, desiccation and are difficult to stain with | | | | The type of mycolic acid can be used to distinguish |
| water based stain such as Gram. | | | | different Mycobacteria. |
| Infection with tubercle bacillus is characterised by the | | | | Mycolic acid isolated from Mycobacteria are called |
| formation of tubercles, hard nodules in the lungs | | | | eumycolic acids which have elevated 60-90 carbon |
| when Mycobacterium tubercle enters the lungs the | | | | atoms. |
| macrophages engulf the pathogen but are unable to | | | | Mycolic acids are complex hydroxylated branched |
| digest the bacteria due to it’s waxy mycolic acid | | | | chain fatty acids with elevated carbon numbers. |
| cell wall. | | | | They may also contain diverse functional groups such |
| Mycobacteria begin to multiply within the | | | | as methoxy, keto, epoxy ester group and |
| macrophages, eventually killing the macrophages that | | | | cyclopropane ring. |
| protect the host. | | | | Mycolic acids containing a methoxy group with double |
| The cycle continues as the bacteria released from | | | | bond or cyclopropane ring are known as |
| dead macrophages are then engulfed by other | | | | methoxymycolic acids. |
| macrophages. | | | | Mycolic acids containing an a methyl-branched ketone |
| The infected macrophages result in inflammatory | | | | are known as ketomycolic acids and those containing |
| response(heat, swelling, dilated capillaries) | | | | an a-methyl-branch epoxide as epoxymycolic acids. |
| The cells at the centre of the tubercle may | | | | Mycolic acid known as wax esters contain a double |
| eventually die, producing either an area of necrosis or | | | | bond or a cyclopropane ring and an internal ester |
| an actual cavity. | | | | group. |
| Mycobacterium tuberculosis can be differentiated | | | | |