Bacteria are unicellular microorganisms which exist more than 3.5 billions of years. The most of bacteria are not harmful for the human organism, some of them are even beneficial for people. For example, lactic acid bacteria are used in the production of cheese, yogurt. Nearly 300-1000 strains of bacteria are located in the small and large intestine. These bacteria are essential in the carbohydrates metabolism, synthesis of vitamins, elimination of pathogenic microorganisms.
Beside beneficial bacteria there is a great number of pathogenic ones. Pathogenic bacteria may enter the human organism and cause different pathological processes. Usually our organism can protect itself from pathogenic microorganisms. These protection mechanism include lysozyme in the saliva, hydrochloric acid in the stomach, body's immune system (lymphocytes), intestinal microflora. In the case when human organism is weak and protection mechanism does not act properly, bacteria may enter the organism and begin multiplying. Pathogenic bacteria release toxic substances which damages different organs and system.
The diagnostic of bacterial infections is based on symptom complex and laboratory investigations which help to determine the exact strain of pathogenic bacteria.
The treatment of bacterial infections include the application of substances called antibiotics. Antibiotics are compounds of natural and half-synthetic origin. All of the antibiotics are dividing into two main groups: bactericidal and bacteriostatic. Bactericidal antibiotics like penicillins and cephalosporin kills bacteria by disturbing the structure of bacterial cells wall. Bacteriostatic antibiotics work by interfering with bacterial growth and replications. Bacteriostatic antibiotics include macrolides and tetracyclines.
Antibiotic are not used to treat viral infections.