Nature of the Bacteria
Mycobacterium tuberculosis (M. tuberculosis) is the bacterium that causes the disease tuberculosis (TB). A distinctive characteristic of the genus Mycobacteria is the presence of a thick lipid-rich cell wall and resistance to the decolourization step of the gram stain (being acid-fast). The acid-fast characteristic of the M. tuberculosis is the result of a waxy, lipid-rich cell wall. The cell envelope of the tubercle bacilli contains a layer beyond the peptidoglycan which is exceptionally rich in lipids, glycolipids and polysaccharides. The bacterium is gram positive bacillus which is an obligate aerobe, is non-motile, a non-endospore forming and is non-capsulated. The microscopic appearance of M. tuberculosis is seen as straight, slightly curved rods approximately 3 x 0.3µm in size. In liquid culture media, the bacteria usually grow as twisted rope-like pellets known as ‘serpentine cords’. M. tuberculosis is capable of growing on a wide range of enriched culture media such as Lowenstein-Jensen medium or Middlebrook medium. The optimum growth temperature of the pathogenic organsim is 35-37°C and unlike most other mycobacteria, it cannot grow at a temperature of 25°C or 41°C. M. tuberculosis is an airborne pathogen that is transmitted from person to person, usually infecting the respiratory tract through inhalation (Greenwood, et al., 2012).
Other key features of M. tuberculosis are its slow growth rate, dormancy, intracellular pathogenesis and genetic homogeneity. In infected animals or synthetic medium, M. tuberculosis has a generation time of about 24 hours. The short generation time contributes to the chronic nature of the tuberculosis disease and long treatment courses for infected patien...
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...ST. A person could show positive for LTBI, when in fact it is the vaccine causing the positive result. There are conflicting policies on the BCG vaccination both nationally and internationally due to the lack of effectiveness and potential loss of the TST (HSE/HSPC, 2010).
Healthcare workers working in close proximity with infected patients are required to take various standard precautions. These standard precautions include hand hygiene, wearing personal protective equipment, appropriate management of sharps and waste and appropriate decontamination of the working environment. For their own protection, a healthcare worker must assume that all blood, body fluids and secretions from patients are potentially hazardous and my cause infection. If the appropriate precautions are taken, healthcare workers can prevent becoming infected with TB themselves (HSE/HSPC, 2010).
Tuberculosis can be caused by one of the four different organisms belonging to the genus mycobacterium: Mycobacterium bovis, Mycobacterium africanum, Mycobacterium microti and Mycobacterium tuberculosis. However, the leading cause of tuberculosis in humans is due to Mycobacterium tuberculosis, 9 which was discovered in 1882 by the German physician Robert Koch.10
...macrophage to kill bacteria that might have escaped from granuloma. Latent TB is characterized by absence of disease activity. It can be detected by TBT and Interferon-γ release assay (IGRA) and chest x-rays. The chest x-ray usually result normal due to the inactivity of the disease. TNF-α helps contain latent TB infection and keeps it from becoming active TB. Patient that have been treated withTNF antagonist are at greater risk of reactivation of LTBI to active TB
Throughout many years tuberculosis has atrociously affected the lives of many people. Many have suffered a horrible death due to this horrid disease. Tuberculosis is a highly contagious disease due to mycobacterium tuberculosis, which initiated about one hundred fifty million years ago. Skeletal abnormalities typical for tuberculosis were found in Egyptian mummies back in 2400 BC. In ancient Greece the Greeks seemed very familiar with tuberculosis only they called it Phtisis. Many years later a disease that was called “ scrofula” was described to be a certain form of tuberculosis. It was referred to as “king’s evil” in England and France, and they believed it could be cured by a royal touch. This practice was put to an end in the year 1714.
In health care facilities many sick patients are treated in isolated or confined spaces. This means that many microorganisms are present in these areas. Patients come in contact with many health care workers (HCW) who can potentially help the spread of these microorganisms and infections between their patients.
In a recent study, the diagnostic role of XpertMTB/RIF demonstrated sensitivities of 98.2% and 72.5% with smear-positive and negative TB, respectively. The tests specificity was 99.2% in patients without Tuberculosis. 26
Standard Precautions reduce the risk of spread of microorganisms from both recognized and unrecognized sources of infection in hospitals. " The use of standard precautions assumes that every person is potentially infected or colonized with an organism that could be transmitted in a health-care setting. As its name implies, standard precautions require the health-care worker to routinely follow basic principles of infection control, such as hand hygiene " (British Journal of Nursing ). The most important things to take into consideration is hand washing donning gloves, donning masks, and donning gowns. During patient care, there is no such thing as reusable equipment, each patient needs new equipment when being assisted. The environment in which the patient is being...
(2014) shed light on two key components for infection control, which includes protecting patients from acquiring infections and protecting health care workers from becoming infected (Curchoe et al., 2014). The techniques that are used to protect patients also provide protection for nurses and other health care workers alike. In order to prevent the spread of infections, it is important for health care workers to be meticulous and attentive when providing care to already vulnerable patients (Curchoe et al., 2014). If a health care worker is aware they may contaminate the surroundings of a patient, they must properly clean, disinfect, and sterilize any contaminated objects in order to reduce or eliminate microorganisms (Curchoe et al., 2014). It is also ideal to change gloves after contact with contaminated secretions and before leaving a patient’s room (Curchoe, 2014). Research suggests that due to standard precaution, gloves must be worn as a single-use item for each invasive procedure, contact with sterile sites, and non-intact skin or mucous membranes (Curchoe et al., 2014). Hence, it is critical that health care workers change gloves during any activity that has been assessed as carrying a risk of exposure to body substances, secretions, excretions, and blood (Curchoe et al.,
Therefore it is possible to introduce different strains of mycobacteria into HeLa cells and study their behavior11. Cellular uptake analysis of M. tuberculosis has also been studied by using HeLa cells. These cells were used to identify a product of M. tuberculosis which stimulates a functional reaction in non-phagocytic mammalian cells12. The virus leads to a cytoskeletal rearrangement in HeLa cells due to recombinant mce1 protein product12. Therefore, usage of HeLa cells permits for the identification of M. tuberculosis product which triggers changes in the target cell.
Mycobacterium tuberculosis (MT) is a slender, rod-shaped, aerobic bacillus which causes tuberculosis. Tuberculosis (TB) is an airborn infection which is transmitted via inhaling droplet nuclei circulating in the air. These droplets are expelled from the respiratory secretion of people who have active TB through coughing, sneezing, and talking (Porth, 2011). Some bacilli stay in the upper airway and are swept out by mucus-secreting goblet cells and cilia on the surface of the airway. Others will escape from this protective mechanism to travel and settle down at alveoli (Porth, 2011). Local inflammatory reaction occurs and macrophages are cells that act as next line defense mechanism to fight with mycobacteria. First they engulf micobacteria, try to reduce their strength and ability, and kill them. In the same way they send antigen to helper T lymphocytes to initiate a cell-mediated immune response (Knechel, 2009). The infected macrophages will send produced cytokines and enzymes to breakdown mycobacteria’s protein. It is the released cytokines that attract T ly...
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
Due to people in a hospital having a lowered immune system and/or a portal of entry that the infectious agent can enter through, because of this it is important for healthcare staff to continuously sterilize their hands and keep up with good hand hygiene practices so that they reduce the risk of spreading infectious material to people who have an already weakened immune system. This is important because in a hospital there is a great reservoir of infection and any microbes present in a hospital environment are more likely to have a greater resistance to anti-microbials as they are constantly used. (Centres for Disease control and Prevention 2012)
People that immune systems that are weaker, tend to be at a greater risk for developing TB. When they breathe in TB bacteria, the bacteria settles in their lungs and start growing because their immune systems cannot fight the bacteria. Tuberculosis can develop within days or weeks after being exposed. However, it is possible for it to develop months or maybe even years after being infected, at a time when the immune system becomes weak for other reasons and is no longer able to fight the bacteria. (Bennett, Raphael 2010)
Mycobacterium tuberculosis is a nonmotile, acid-fast, obligate aerobe. The bacilli are 2-4 um in length and have a very slow generation time of between 15 and 20 hours. The cell wall of the mycobacterium is unique in that it is composed mainly of acidic waxes, specifically mycolic acids. M. tuberculosis is unusually resistant to drying and chemicals, contributing to the ease with which it is transmitted.
Infection rates of TB are high, especially when in frequent or close contact with individuals with active TB. One study estimates an infection rate of about 22% and a diagnosis with positive sputum smear is the strongest indicator of infectiousness. 19 However, contrary to common belief, sputum smear-negative patients are also infectious, with a study in San Francisco attributing 17% of transmissions to such cases. 20
There are several ways to prevent tuberculosis. One is to control existing infections from those infected including people, pets, and cows. Unfortunately, more than 1/3 of the population has tuberculosis, making it hard to contain every case of tuberculosis. The BCG vaccine exists, but it is not very useful in countries like the US. The body’s defenses against tuberculosis are effective but fail once the immune system becomes suppressed. Antibiotics can be used to help prevent tuberculosis, but tuberculosis quickly grows resistant to antibiotics. Much needed research is being done to find a way to fight off and prevent tuberculosis.