In the Quest of Drugs for Bad Bugs: Are Newer Fluoroquinolones Any Better?

Sir, The consumption of antimicrobials and the development of bacterial resistance go hand in hand. This is evident from the fact that soon after the discovery of the first antimicrobial compound, penicillin, reports of bacteria developing resistance to it started appearing.[1] Fluoroquinolones are definitely the most widely used and misused antimicrobial agents in most of the developing and developed nations. Since the serendipitous discovery of the first member of the quinolone class of drugs (nalidixic acid, which truly is a naphthyridine derivative) as a by-product during synthesis of antimalarial compound, chloroquine, in 1962,[2] a whole spectrum of newer quinolone compounds have been discovered which are in clinical use nowa-days; some of those having been claimed to be effective against multi drug resistant (MDR) organisms. The definition of various classes of drug resistance also varies among scientific community. One group proposes the carrying out surveillance of organisms on the basis of degree of MDR, and define pan drug resistance (PDR) and extreme drug resistance (XDR) in gramnegative bacilli (GNB) in the following manner.[3]