Knowledge about Antibiotics

To knowledge people how to use antibiotics correctly and understand functioning of each antibiotic is not to support using antibiotic in shrimp farming, but to knowledge shrimp farmer not using it incorrectly or not using prohibited antibiotics which may collapse shrimp farming in Thailand and may cause permanent antibiotic resistance in the treatment of human disease.

Compared to the knowledge of drugs such as opium, amphetamine, cocaine, heroin, the educator aims for people to know these drugs so that they will not get close to and try to avoid and protect these drugs to their lifes.

Antibiotics classified by the effect to microorganisms

1. Bactericidal is antimicrobial agent that destroys pathogen.  Generally, it functions to cell wall and cell membrane of bacteria.

2. Bacteriostatic is an antimicrobial agent that inhibits growth of microorganisms.  It functions to inhibit protein formation and needs white blood cell immune system to destroy pathogen.

Antibiotics classified by the mechanism of action:

1. Functions to inhibit the formation of cell wall such as Penicillin, Cephalosporin, Vancomycin. 

Bacteria cell wall is the outmost layer of cell which is solid and full of holes.  The cell wall works to protect the outside irritation and prevent cell membrane from swollen effect.  The components of gram-positive and gram-negative bacteria cell wall are different.  The cell wall of gram-negative bacteria is stronger and more difficult to be destroyed by antimicrobial agents.

This group of antibiotics works to inhibit the formation of bacteria cell wall by destroying bacteria cell wall.  The cell wall is broken and bacteria will immediately died.  This antibiotic is an antimicrobial agent that kill bacteria directly (Bactericidals).  This antibiotic group is highly safe due to most animals do not have cell wall.

2. Effects to cell membrane such as Polymyxin - B, Ketoconazole, Amphotericin-B, Colistin.  Bacteria cell membrane is the inner layer next to cell wall composed of protein and fat.  The major function of cell membrane is to control all components of cell and to prevent the flow out of fine molecules such as amino acid and all minerals.  This group of antibiotics directly effects to bacteria cell to be broken and causes cytoplasm in bacteria cell leaking out of that cell and bacteria finally die.  Actually, animal cell also has cell membrane but has different types of membrane from bacteria.  This group of antibiotics is most toxic and it effects to bacteria cell much better than to animal cell.

3. Inhibits protein formation such as Chloramphenical, Tetracyclin, Erythromycin, Aminoglycoside.  The protein formation of bacteria derives from "Ribosome" in bacteria cell.  Ribosome functions to synthesize protein to be applied into bacteria cell.  When the process of protein formation is inhibited the activities in bacteria cell is also ceased.  This group of antibiotics does not kill bacteria cell directly but weakens cell by lacking of nutrients.  The bacteria cell will be terminated by animal immunes eventually.    

4. Malfunctions process of protein formation such as Spectinomycin, Streptromycin, Aminoglycoside.

To inhibit growth of bacteria that causes bacteria generate the abnormal protein is an alternative of bacteria inhibitor.  The antibiotics cause ribosome in bacteria create abnormal protein and toxic to bacteria cell.  Bacteria are finally died.  These antibiotics are Spectinomycin, Streptromycin, Aminoglycoside (Ganamycin, Gentamycin, Neomycin, Tobramycin)

5. Inhibits Nucleic Acid Formation such as Rifampicin, Quinolone, Metronidazole.  Normally, bacteria is divided by DNA formation.  The antibiotics inhibits DNA gyrase enzyme that is a main factor to form new set of DNA for bacteria divide process.  Therefore, bacteria cannot create DNA to divide itself for its growth and bacteria are finally died.  These antibiotics are Rifampicin, Metronidazole, Quinolone (Norfloxacin, Ciprofloxacin, Enrofloxacin, Pefloxacin) 

6. Interferes metabolize synthesis that is essential to pathogen such as Sulfonamide, Isoniacid.

All bacteria cells need to be divided and need folic acid for their survives.  Bacteria cannot afford folic acid from external environment but need to generate folic acid internally from themselves for dividing process and their growths.  When the process of folic acid formation is inhibited, bacteria will finally die.  These antibiotics are Sulfonamide (Sulfaguadinine, Sulfamethoxazole, Trimethoprim)