IDIOT

Tetracyclines have the broadest spectrum of antimicrobial activity, effective against a remarkably wide variety of organisms.

Tetracyclines inhibit bacterial protein synthesis by blocking the attachment of the transfer RNA-amino acid to the ribosome. More precisely they are inhibitors of the codon-anticodon interaction. Tetracyclines can also inhibit protein synthesis in the host, but are less likely to reach the concentration required because eukaryotic cells do not have a tetracycline uptake mechanism.

Tetracycline can have toxic effects on development of bone. Therefore, tetracyclines are generally not recommended during pregnancy or nursing. Tetracyclines may cause discoloration of teeth if used in children less than 8 years of age.

The quinolones are a family of broad-spectrum antibiotics and a bactericidal drugs, actively killing bacteria.

Fluoroquinolones interfere with bacterial DNA metabolism by the inhibition of two enzymes, Topoisomerase II and Topoisomerase IV. In Gram-negative organisms DNA gyrase is the primary target, whereas in Gram-positive bacteria Topoisomerase IV was recently found to be most affected.

Resistance to quinolones can evolve rapidly, even during a course of treatment. An important precaution is that unnecessary use or abuse of antibiotics can encourage drug-resistant strains of bacteria to develop and proliferate. These drug-resistant strains then become difficult, or even impossible, to treat. Bacteria found in hospitals appear to have become especially resilient, and are causing increasing difficulty for patients and the doctors treating them.

Aminoglycosides that are derived from bacteria of the Streptomyces genus are named with the suffix -mycin, while those which are derived from Micromonospora are named with the suffix -micin.

Aminoglycosides are used for serious gram-negative infections, especially Pseudomonas aeruginosa. They are active against most gram-negative aerobic bacilli but lack activity against anaerobes and most gram-positive bacteria, except for most staphylococci. It Inhibit protein synthesis by binding to a portion of the bacterial ribosome. Most of them are bacteriocidal.

They are not absorbed from the intestine, they are usually given by injection. Aminoglycosides are quite toxic, with side effects including damage to the ears and kidneys. For this reason they are only used for infections that do not respond to other antibiotics.

Macrolides are used to treat infections such as respiratory tract and soft tissue infections. The antimicrobial spectrum of macrolides is slightly wider than that of penicillin, and therefore macrolides are a common substitute for patients with a penicillin allergy.

The mechanism of action of the macrolides is inhibition of bacterial protein biosynthesis by binding reversibly to the subunit 50S of the bacterial ribosome, thereby inhibiting translocation of peptidyl tRNA. This action is mainly bacteriostatic, but can also be bactericidal in high concentrations. Macrolides tend to accumulate within leukocytes, and are therefore actually transported into the site of infection.

Cephalosporin , any of a group of more than 20 antibiotics derived from species of fungi of the genus Cephalosporium and closely related chemically to penicillin. It act against both gram-positive and gram-negative by inhibiting bacterial cell wall synthesis and it is also a bactericidal.

First-generation cephalosporins are predominantly active against gram-positive bacteria.

Second-generation cephalosporins have a greater Gram-negative spectrum while retaining some activity against gram-positive cocci.

Third-generation cephalosporins have a broad spectrum of activity and further increased activity against Gram-negative organisms. Some members of this group have decreased activity against Gram-positive organisms.

Fourth-generation cephalosporins are extended-spectrum agents with similar activity against Gram-positive organisms as first-generation cephalosporins. They also have a greater resistance to beta-lactamases than the third-generation cephalosporins. Many can cross blood brain barrier and are effective in meningitis. They are also used against Pseudomonas aeruginosa.