Tuberculosis as an Airborne Infectious Bacterial Disease - Coursework Example

Tuberculosis Tuberculosis is an airborne infectious bacterial disease. This paper evaluates the symptoms of the disease and further evaluates the use of Gram staining and acid-fast staining as the common laboratory tests for the causative bacterium known as Mycobecterium tuberculosis. Acknowledging the severity of the disease, the paper offers some of the common preventive approaches that could be used to keep TB away. Introduction Tuberculosis or TB refers to an infectious disease that is caused by a bacterium known as Mycobecterium tuberculosis that mostly affects the lungs although it also damages other parts of the body (Pagana 770). It is mostly spread from a person to another through the air when the infected person talks, sneezes, sings, laughs or coughs. However, the American Lung Association, ALA observes that contracting TB is not easy and one has to be close to someone with TB for a long time so as to be infected. It is highly prevalent among those infected with HIV, the young, the elderly, those injecting illegal drugs and those who have suffered the disease before or not treated properly before. It could be fatal if not treated. Symptoms Normally, people infected with TB show no symptoms. However, in severe cases of TB disease, the Centers for Disease Control and Prevention, CDC observes that such a patient could experience a persistent cough, lasting for three weeks or more, loss of appetite, weight loss, constant fatigue, fever, night sweats and coughing up blood or sputum. ALA cautions that these symptoms could also be observed with other diseases hence the importance of seeking advice of a healthcare provider and allowing for diagnosis of TB. Diagnosis There are various tests that could be conducted to diagnose TB. TB skin test and chest x-ray are cited by Wyka, Mathews and Tutkowski as good preliminary indicators of the disease (216). Should the findings from these procedures indicate a high likelihood of TB infection, then, organism recovery procedures and sputum smear cultures would needed for further evaluation. Of these tests, the common ones undertaken in a laboratory setting are the sputum Gram staining and acid-fast staining. I. The sputum Gram staining Generally, Gram staining is a standard procedure that has been used in clinical microbiology to assess the quality of specimen so as to give preliminary diagnostic information. There are various assessment systems used in sputum Gram staining method. Various quantitative criteria inform the development of screening criteria to determine the quality of specimen based on the fact that abundant squamous epithelial cells indicate superficial oropharyngeal contamination. As noted by Pagan, this procedure is simple but does not divulge details of the bacterial other than arrangement and morphology (773). Gram stain is a commonly used differential stain in microbiology laboratories to differentiate bacteria based on the structure of their cell wall characteristics. As such, Gram-positive cell walls would exhibit thick peptidoglycan layer extending beyond the plasma membrane. It would have characteristic polymers known as teichoic and lipoteichoic acids sticking above the peptidoglycan because of their negative charge that makes the cell wall negatively charged. These acids play a crucial role in the body for recognizing foreign bacteria (Pagana 773). In this Gram staining test, Gram-positive cell walls would stain purple or blue with the Gram stain. On the other hand, Gram-negative cell walls have been found to be more complex. Their thin peptidoglycan layers together with the outer membrane extend beyond the membrane of the plasma. Periplasmic space is the space between the outer and plasma membrane. The outer membrane occurring on the outer leaflet would overly have a molecule referred to as lipopolysaccharide, LPS. It is an important endotoxin that triggers the immune response of the body and gives the cell its overall negative charge. On the outer membrane are porin proteins which allow small molecules to pass through. The thin peptidoglycan layer and the outer membrane would be joined by lipoproteins (Pagana 774). With Gram stain, Gram-negative cells stain pink. The Gram staining procedure starts with placing a drop of sterile water on a slide. The sputum would then be introduced, followed by air drying and heat fixing. Thereafter, the smear would be covered with the primary stain, say Crystal Violet, for a minute. The slide would then be washed off with water. The Gram’s mordant, in this case Iodine, would be added for a minute before washing with water. It would then be decolorized with 95% ethanol, taking caution as argued by Wyka, Mathews and Tutkowski to stop immediately the purple color stops leaching off (216). This would then be immediately washed with water and covering the smear with Safranin for about half a minute. The slide’s top and bottom would then be washed and blotted with bibulous paper (Pagana 775). The objective lens of a microscope would then be used to view, first the focus line, then the smear. The observation of a rod-like tiny pink (Gram) substance would be an indication of the likely presence of Mycobecterium tuberculosis thus TB. II. Acid-fast stain Mycobecterium tuberculosis and other Nocardia species are referred to as acid-fast. According to Pagana, this is because they retain carbol fuchsin primary dye during the acid-fast staining procedure in spite of decolorizing using a powerful solvent acid-alcohol that is 95% ethanol and 3% HCl (775). Almost all the other bacteria variants are not acid-fast. Acid-fast bacteria genera would have waxy hydroxyl-lipid in their call walls, known as mycolic acid. This mycolic acid hinders protoplasm from being decolorized by acid-alcohol. This acid-fast stain would be referred to as differential stain. The Ziehl Neelsen acid-fast stain laboratory procedure for testing TB as given by Pagana entails the addition of sterile water on a microscope slide (776). A heavy smear of the sputum would then be made and thoroughly mixed with the loop. This would then be air dried and well heat-fixed. The smear would then be covered with cardolfuchsin dye, placing a towel paper on the dye. Wyka, Mathews and Tutkowski advise that the paper towel should be saturated with dye and because of the carcinogenic effect of carbolfuchsin, it would be advisable to put on gloves (217). The slide would then be placed over dry heat for about 2 minutes before cooling and rinsing with water. It would then be decolorized using a drop of acid alcohol. After 15 seconds, the top and bottom of the slide would be washed with water. The bottom of the slide would then be cleaned well and counterstained with Methylene Blue for between 30 and 60 seconds. The slide would then be washed and blotted with bibulous paper. Focusing on the microscope would indicate a hot pink stain if Mycobecterium tuberculosis is present. Prevention of TB People with TB which has not developed into active TB disease could get preventive therapy. The aim of this is to kill the bacteria that could not be causing any harm at that moment but which risk future damages as noted by ALA. Isoniazid (INH) has been documented by CDC as a common preventive therapy taken on a daily basis for between 6 and 9 months. Adherence to the prescribed dosage would be crucial in averting the development of active TB disease. Additionally, the bacille Calmette-Guerin, BCG vaccine has been used in many countries where TB is prevalent. This, however, is not used in the US due to what ALA documents as the low chances of infection in the country. Those diagnosed with TB should keep off other people within the first week of treatment. At individual level, people should cover their mouths when coughing, sneezing or laughing and adequately ventilating their rooms. Conclusion Therefore, TB is an airborne disease attributed to the bacterium, Mycobecterium tuberculosis. Sputum Gram staining and acid-fast stain tests are the common laboratory tests for the bacteria. TB could go unnoticed because it does not have any symptoms until it becomes a disease. For this reason, it is important to seek medical attention in case of any suspicion. INH prevents TB from developing into the TB disease while BCG vaccine protects those in TB prevalent countries from contracting the disease. Personal measures should also be taken to avoid contaminating the air for those diagnosed with TB and for the safe ones to ensure adequate ventilation of their rooms. This way, people would be free of TB infections. Works Cited American Lung Association. “Tuberculosis.” Lung.org. 2014. Web. 16 Apr. 2014. Centers for Disease Control and Prevention. “Tuberculosis (TB).” Cdc.gov. 13 Mar. 2013. Web. 16 Apr. 2014. Pagana, K. D. Mosby’s manual of diagnostic and laboratory tests. 5th ed. St. Louis, Missouri: Mosby, 2014. Print. Wyka, K., P. Mathews and J. Tutkowski. Foundations of Respiratory Care. 2nd ed. Clifton Park, NY: Delmar, 2012. Print. Read More