Nalidixic acid is credited to be the first quinolone synthesized in laboratory in 1962. Its chemical structure is shown in Fig. 45.16. It is a broad spectrum chemotherapeutic agent and is useful against gram-negative bacteria (causing urinary tract infection) and some gram-positive ones. Nalidixic acid is bactericidal and is effective when administered orally. This antibiotic sometimes causes side effects, particularly [...]
In this article we will discuss about:- 1. Structure of Tetracylines 2. Antibiotic Spectrum of Tetracylines 3. Mechanism of Action. Structure of Tetracylines: All members of the group of tetracyclines consist of a common four-ring structure to which a variety of side chains (R1, R2, R3) are attached (Fig. 45.14). Antibiotic Spectrum of Tetracylines: Tetracyclines are broad-spectrum bacteriostatic antibiotics active [...]
The term antibiotic was derived from antibiosis, a phenomenon of antagonism of one organism by another. Antibiosis has been observed by many scientific workers dealing with microorganisms growing on plates (petridishes), but the credit of discovering and exploiting the product (antibiotic) for useful purpose goes to Alexander Fleming (1928). While working in a hospital laboratory in London, he found that [...]