Antibiotics is one of most prescribed group of medications. Antibiotics are antibacterial (antimicrobial agents) that kills bacteria(bactericidal) or stop the growth of the bacteria(bacteriostatic action).

Antibiotics are used to treat bacterial infections and are not indicated for the viral infections. Currently there is a big variety of antibiotics available. All the antibiotics are divided into two main groups according to the action mechanism:

• Antibiotics with bactericidal action(penicillins, cephalosporins, aminoglycoside)
• Antibacterial with bacteriostatic action(macrolides, tetracyclines)

Penicillins and cephalospororins are the most prescribed group of antibiotics. They belong to half-synthetic beta lactam antibiotics. These antibiotics work by inhibiting the enzymes responsible for the production of peptidoglycan. Peptidoglycan is a biopolimer that is a main structural component of the bacterial cell wall. The blockage of peptidoglycan synthesis leads to the lysis of the microorganisms.

Another group of preparations are aminoglycosides. However, these antibiotics are prescribed in rare cases. The most of aminoglycosides possesses nephrotoxicity, ototoxicity and cab cause neuromuscular blockage. Bactericidal action of aminoglycosides is related to the interfering with the synthesis of proteins on the ribisomes in the microbial cells. When aminoglycosides are used with penicillins and cephalosporins the sinergism against gram-positive and gram-negative microorganisms is observed.

Among all bacteriostatic antibiotics macrolides and tetracyclines are the most indicated groups. Therapeutic effect of macrolides is associated with inhibiting the synthesis of proteins on the ribosomes in the microbial cell. As usual macrolides exert bacteriostatic action, however in high amounts are able to exert bactericidal action on some microorganisms. Besides antibacterial action, some macrolides possesses immunomodulatory and anti-inflammatory action.

Another group of bacteriostatic antibiotics are used less frequently as many microorganisms became resistant to the this type of antibiotics. Bacteriostatic effect of the tetracyclines is associated with inhibiting the synthesis of proteins. Tetracycline are indicated in clamydia infections, rickettsial disease, some zoonosis, severe acne.

Antibiotics are indicated and used only in the cases of the bacteria is sensitive to the antibiotics. There some specific tests like antibiogram that will help to determine the right antibiotic and corresponding dose.