TITLE: ANTIBIOTICS : ARE THEY REALLY MAGIC BULLETS?

The human body is exposed to substances that have the potential to cause harm on a daily basis. The body protects itself against these substances in several ways. Our natural defences give the body an opportunity to fight off invading microbes that may cause disease. The first line of defence is non-specific and aims to stop microbes from entering the body. The skin and mucous membranes act as a physical barrier preventing penetration by more harmful microbes which could lead to infection (1). The normal body flora on the surfaces of the body, reduce the area available for pathogens to attach to, as well as acting as a competitor for suitable nutrients. The body also produces several antimicrobial substances that kill or break down bacteria. A specific example of a physical barrier is when the blood produces a clot to seal the wound to prevent microbes from entering when the skin has been cut.

The second line of defence is also non-specific and involves the process of phagocytosis. A type of white blood cell, called phagocytes, send out pseudopodia to attack the pathogens. Digestive enzymes are then released which break down the harmful microbes (1). Conversely, specific immunity is when resistance is given to a particular foreign agent such as a virus or bacteria, known as antigens. These antigens work to attack the pathogen by causing specific cells to replicate and produce proteins to provide protection from the pathogen (2). Repeated exposure increases the effectiveness of specific immune responses and some diseases, like chickenpox, need only to be contracted once to give immunity for life. Vaccinations are also readily available for many common diseases which enable the individual to produce antibodies against the antigens thereby preventing contraction of the disease.