A-level Biology OCR [New Spec] - Disease: Bacterial Pathogens | A-level Biology | OCR, AQA, Edexcel

Disease: Bacterial Pathogens in a Snap! Unlock the full A-level Biology course at http://bit.ly/2VSxupH created by Adam Tildesley, Biology expert at SnapRevise and graduate of Cambridge University. SnapRevise is the UK’s leading A-level and GCSE revision & exam preparation resource offering comprehensive video courses created by A* Oxbridge tutors. Our courses are designed around the OCR, AQA, SNAB, Edexcel B, WJEC, CIE and IAL exam boards, concisely covering all the important concepts required by each specification. In addition to all the content videos, our courses include hundreds of exam question videos, where we show you how to tackle questions and walk you through step by step how to score full marks. Sign up today and together, let’s make A-level Biology a walk in the park! The key points covered of this video include: 1. Introduction to Bacterial Pathogens 2. Meningitis 3. Bacterial Diseases in Plants 4. Tuberculosis Transmission 5. Tuberculosis Pathogenesis 6. Tuberculosis Treatment and Prevention Introduction to Bacterial Pathogens Most diseases in humans are caused by bacteria. Bacteria belong to the Prokaryotae kingdom. Prokaryotes are smaller than eukaryotic cells but they can reproduce rapidly. Bacteria usually cause disease by damaging cells directly or releasing toxins. Bacterial Meningitis Bacterial meningitis is a bacterial infection of the protective membranes on the surface of the brain (meninges). Bacterial meningitis is usually caused by either Streptococcus pneumoniae or Neisseria meningitidis. The bacterial infection can spread to the blood causing septicaemia (blood poisoning) which leads to death unless treated immediately. Meningitis is very serious - around 10% of infected individual die while 25% can be left with permanent brain or nerve damage. Antibiotics can be used to treated meningitis if administered early and vaccines can also protect against meningitis. Bacterial Diseases in Plants Bacteria can also infect plants. Ring rot is an example of a bacterial disease in tomatoes and potatoes. Ring rot causes the vascular tissues to decay and decreases the yield of potatoes and tomatoes. Tuberculosis Transmission Tuberculosis (TB) is a disease caused by the bacterium Mycobacterium tuberculosis. TB normally infects the cells in the lungs, however it can also spread to other parts of the body. TB specifically infects macrophages in the lungs and inhibits their lysosomes so it can survive. TB is transmitted in droplets in the air which can be inhaled. TB infection therefore normally requires long periods of close contact with an infected person. Tuberculosis Pathogenesis A person infected with TB for the first time will get what is called primary TB. In primary TB, the person’s lungs will be infected and they will be infected and they will experience fatigue, fever and weight loss. In a healthy person, primary TB will eventually be controlled by the immune system and won’t develop further. In an immunocompromised person, TB may develop further - this is called secondary TB. In secondary TB phagocytic cells accumulate around the infected macrophage. This causes cell death and produces a lesion called a granuloma which causes the lung tissue to be damaged. This causes chest pain and can eventually lead to death. TB can also be latent which means it is present in the body but is not actively replicating so it causes no symptoms. Tuberculosis Treatment and Prevention TB is more likely to spread when living conditions are overcrowded or housing is damp. Improving living conditions can help prevent the spread of TB. Pulmonary TB (TB just in the lungs) can be treated by extensive use of a combination of antibiotics over 6 months. It is getting more difficult to treat TB nowadays because Mycobacterium has started to become resistant to some antibiotics. If TB is resistant to two antibiotics it is called multidrug resistant tuberculosis (MDR-TB). If TB is resistant to three or more antibiotics it is called extensively drug resistant tuberculosis (XDR-TB). Summary Bacteria cause disease by damagng cells - usually by causing lysis or releasing toxins Bacterial meningitis is an infection of the meninges by bacteria If bacterial meningitis is not treated quickly, it can lead to blood poisoning, brain damage or death Ring rot is a bacterial disease that causes vascular decay in tomatoes and potatoes Tuberculosis (TB) is a disease of the lungs caused by Mycobacterium Mycobacterium infects macrophages in the lungs and inhibits their lysosomes Disease is caused by the formation of granulomas which cause lesions in the lungs TB can be prevented by improving living conditions, hygiene and sanitation TB is treated using a combination of antibiotics but is becoming increasingly resistant to antibiotics