Much of our experience with bacteria involves disease. Although some bacteria do cause disease, many kinds of bacteria live on or in the human body an prevent disease. Bacteria associated with the human body outnumber body cells by ten to one. In addition, bacteria play important roles in the environment and industry.
Bacteria and human health:
We have all had bacterial diseases. Bacteria cause many cases of gastroenteritis, sometimes called stomach flu. Perhaps the most common bacterial disease is tooth decay. Dental plaque, the sticky film on our teeth, consists primarily of masses of bacteria. These bacteria ferment the sugar we eat to produce acids, which over time can dissolve the enamel of teeth and create cavities in the teeth.
Tooth decay provides a good example of how multiple factors contribute to bacterial disease. The human body hosts the bacteria, the diet supplies the sugars, and the bacteria produce the acid that damages the teeth.
This in conclusion means these are bad bacteria.
How the body fights bacterial disease:
Our immune system is designed to protect us against harmful bacteria. It works to keep our normal micro flora in check and also to eliminate invaders from outside the body. Some immune system defences are built in: the skin acts as a barrier to bacterial invaders, and antimicrobial substances in body secretions such as saliva and mucus can kill or stop the growth of some disease-causing bacteria. We acquire another immune-system defence through exposure to disease-causing bacteria.
ANTIBIOTICS:
An Antibiotic is a substance that suppresses the growth of micro-organisms such as bacteria and fungi, and they are produced by some bacteria to prevent other bacteria from growing near them and using up their food. Over 8000 antibiotics are known to science, but we are always looking for more and currently about 200-300 more are discovered each year. Antibiotics are used to treat disease caused by bacteria or to prevent these diseases from occurring in the first place. The following list gives important antibiotics produced by bacteria. Penicillin is not on the list because it is produced by a fungus called Penicillum chrysogenum.
Antibiotics produced by Bacteria:
- Tetracycline
- Sreptomycin
- Cyclohexamide
- Neomycin
- Cycloserine
- Erythromycin
- Kanamycin
- Lincomycin
- Nystatin
- Polymyxin B
- Bacitracin
In many cases the immune system can wipe out a bacterial infection on its own. But sometimes people become so sick from a bacterial disease that hey require medical treatment. Antibiotics and other antibacterial drugs are the major weapons against disease-causing bacteria. Antibiotics work in a number of ways to kill bacteria or suppress their activity. Over time, however, bacteria can become more and more difficult to cure.
In an effort to control antibiotic resistance, physicians have tried to limit the use of antibiotics.
BACTERIA AND THE ENVIROMENT:
Bacteria play a major role in recycling many chemical elements and chemical compounds in nature. Without such bacterial activities as the recycling of carbon dioxide life on earth would be impossible. Plants use carbon dioxide to grow and in the process they produce the oxygen humans and other animals breathe. We would drown in garbage and wastes if bacteria did not speed the decomposition of dead plant and animal matter.
NITROGEN FIXATION:
Bacteria play a key role in making soil fertile. They convert nitrogen in Earth’s atmosphere into the nitrogen compound ammonia, which plants need to grow. Bacteria are the only organisms able to carry out this biochemical process known as Nitrogen Fixation. The bacteria able to fix atmospheric nitrogen usually live in association with plants, often integrated into the plant tissue.
These are friendly bacteria
BACTERIA IN FOOD:
Most people would think bacteria in or on food can only be harmful. True, food poisoning caused by bacteria and their products is a serious problem, however, certain bacteria are safe in food, and are required for the desired taste and texture.
Bacteria are commonly used in dairy products. The good bacteria in dairy products are introduced at a very simple level here. Sour cream and crème fresh are both the products of cream after bacteria were allowed to grow in it. The difference in flavour, texture and behaviour all result from the differences in bacteria required to produce the two products. Buttermilk is low in fat, cheese comes in many variations. Yogurt is probably one of the oldest forms of fermented milk.
It is not dangerous to eat food containing bacteria. Certainly not, as long as they are the right kind of bugs. It may even be beneficial to eat dairy products with living cultures, although the evidence is still controversial. (Source: New York Times Science Q & A) ---.0
BIOLOGICAL WARFARE:
Biological weapons are a unique class of weapons, living micro organisms. These biological agents represent a dangerous military threat because they are alive, and are therefore unpredictable and uncontrollable once released. This is one important reason that biological weapons have rarely been used.
Biological warfare agents include bacteria, viruses, fungi and other micro organisms that can kill or incapacitate. Since they can reproduce, biological agents have the unique potential to make an environment more dangerous over time. If used for hostile purposes any disease-causing micro organism could be considered a weapon. For the purpose of warfare, specific characteristics of certain agents make them more likely to be used than others.
Not only is this not a friendly aspect to bacteria but a very dangerous one at that!
Multi resistance:
When penicillin became widely available during the second world war, it was a medical miracle, rapidly vanquishing the biggest wartime killer (infected wounds). Discovered initially by a French medical student, Ernest Duchesse, in 1896, and then rediscovered by Scottish physician Alexander Flemming in 1928, the product of the soil mould Penicillium crippled many types of disease-causing bacteria. But just four years after drug companies began mass producing penicillin in1943, microbes began appearing that could resist it.
The first bug to battle penicillin was staphylococcus aureus. This bacterium is often a harmless passenger in the human body, but it can cause illness, such as pneumonia or toxic shock syndrome, when it overgrows or produces a toxin.
In1967, another type of penicillin-resistant pneumonia, caused by streptococcus pneumonia and called pneumococcus, surfaced in a remote village in Papa New Guinea. At about the same time, American military personnel in southeast Asia were acquiring penicillin-resistant gonorrhoea from prostitutes. By 1976, when the soldiers had come home, they brought the new strain of gonorrhoea with them, and physicians had to find new drugs to treat it. In 1983, a hospital-acquired intestinal infection caused by bacterium Enterococcus faecium joined the list of bugs that outwit penicillin.
Antibiotic resistance spreads fast. Between 1979 and 1987, for example, only 0.02 percent of pneumococcus strains infecting a large number of patients surveyed for the national Centres for Disease Control and Prevention were penicillin-resistant. CDC’s survey included 13 hospitals in12 states. Today 6.6 percent of pneumococcus strains are resistant, according to a report in the
June15, 1994, journal of the American Medical Association by Robert F.Breiman, M.D.,and colleagues at CDC. The agency also reports that in 1992, 13300 hospital patients died of bacterial infections that were resistant to antibiotic treatment.
The increased prevalence of antibiotic resistance is an outcome of evolution. Any population of the organisms, bacteria included, naturally includes variants with unusual traits, in this case, the ability to withstand an antibiotic’s attack on a microbe. When a person takes an antibiotic, the drug kills the defenceless bacteria, leaving behind, or “selecting,” in biological terms, those that can resist it.
CROSS INFECTION:
Bacteria can be spread easily in a number of ways:
- A person with a cold can spread the infection by coughing and/or sneezing
- Bacteria or viruses can be passed on by touching or shaking hands with another person.
- Touching food with dirty hand will also allow viruses or bacteria from the intestine to spread.
- Body fluids such as blood, saliva and semen can contain the infecting organisms and transmissions of such fluids, for example by injecting or sexual contact, is important, particularly for viral infections like hepatitis or aids.
BIOREMEDIATION:
Bioremediation refers to the use of micro organisms, especially bacteria, to return the elements in toxic chemicals to their natural cycles in nature. It may provide an inexpensive and effective method of environmental clean up, which is one of the major challenges facing human society today.
Bioremediation has helped in cleaning up oil spills, pesticides, another toxic materials. For example, accidents involving large spills that pollute coastlines and harm wildlife. Bacteria and other micro organisms can convert the toxic materials in crude oil to harmless products such as carbon dioxide. Adding fertilizers that contain nitrogen, phosphorus, and oxygen to the polluted areas
promotes the multiplication of bacteria already present in the environment and speeds the cleanup process.
Chemosynthesis:
Bacteria are major players in cycles of other elements in the environment. Chemosynthetic bacteria use chemical energy, instead of the light energy used by plants, to change carbon dioxide into something that other organisms can eat. Chemosynthesis occurs in vents at the bottom of the ocean, where light is unavailable for photosynthesis but hydrogen sulphide gas bubbles up from below Earth’s crust. Life can develop around these vents because bacteria use the hydrogen sulphide gas in changing carbon dioxide into organic nutrients. The hydrogen sulphide gas coming up from Earth’s mantle is extremely hot, but bacteria in these vent communities are adapted to the high temperatures.
MY CONCLUSION:
When all facts are considered, bacteria are more helpful than harmful. Humans have wide variety of users, such as ; making cheese and butter, decomposing waste in sewage plants, antibiotics. Bacteria is also a best friend to our ocean, plants, animals, and air, it loves all the elements of our environment and is good to them!
Bacteria have been able to survive without us, but we could never live without them!
Therefore I would consider bacteria to be a friend!
Reference: http:/Encarta.msn.com/encyclopedia/bateria.html
Reference: http:/www.ncbi.nlm.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uid
Reference: New York Times Science Q & A
Reference: Cow & gate Premium baby formula (Probiotic)
Reference: Biochemistry, Martin Carr and Bob Cordell, 1992, London
Reference: Understanding Biology for advanced level, fourth edition, Glenn and Susan Toole, 1987, 1991, 1995, 1999, Stanley Thornes (publishers) London
Reference: A-level Biology, W D Phillips and T J Chilton, 1989-2001, Oxford University Print, Oxford.
