Nalidixic acid
Encyclopedia
Nalidixic acid is the first of the synthetic quinolone
antibiotic
s. In the technical sense, it is a naphthyridone, not a quinolone: its ring structure is a 1,8-naphthyridines nucleus that contains two nitrogen atoms, unlike quinoline
, which has a single nitrogen atom.
Synthetic quinolone antibiotics were discovered by George Lesher and coworkers as a byproduct of chloroquine
manufacture in the 1960s.
Nalidixic acid is effective against both gram-positive
and gram-negative
bacteria. In lower concentrations, it acts in a bacteriostatic manner; that is, it inhibits growth and reproduction. In higher concentrations, it is bactericidal, meaning that it kills bacteria instead of merely inhibiting their growth.
It is especially used in treating urinary tract infections, caused, for example, by Escherichia coli
, Proteus
, Shigella
, Enterobacter
, and Klebsiella
..
It is also a tool in studies as a regulation of bacterial division. It selectively and reversibly blocks DNA replication in susceptible bacteria. Nalidixic acid and related antibiotics inhibit a subunit of DNA gyrase
and induce formation of relaxation complex analogue. It also inhibits the nicking dosing activity on the subunit of DNA gyrase that releases the positive binding stress on the supercoiled DNA.
It is the only FDA approved quinolone for treating UTI infections in children (3).
Quinolone
The quinolones are a family of synthetic broad-spectrum antibiotics. The term quinolone refers to potent synthetic chemotherapeutic antibacterials....
antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s. In the technical sense, it is a naphthyridone, not a quinolone: its ring structure is a 1,8-naphthyridines nucleus that contains two nitrogen atoms, unlike quinoline
Quinoline
Quinoline is a heterocyclic aromatic organic compound. It has the formula C9H7N and is a colourless hygroscopic liquid with a strong odour. Aged samples, if exposed to light, become yellow and later brown...
, which has a single nitrogen atom.
Synthetic quinolone antibiotics were discovered by George Lesher and coworkers as a byproduct of chloroquine
Chloroquine
Chloroquine is a 4-aminoquinoline drug used in the treatment or prevention of malaria.-History:Chloroquine , N'--N,N-diethyl-pentane-1,4-diamine, was discovered in 1934 by Hans Andersag and co-workers at the Bayer laboratories who named it "Resochin". It was ignored for a decade because it was...
manufacture in the 1960s.
Nalidixic acid is effective against both gram-positive
Gram-positive
Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...
and gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
bacteria. In lower concentrations, it acts in a bacteriostatic manner; that is, it inhibits growth and reproduction. In higher concentrations, it is bactericidal, meaning that it kills bacteria instead of merely inhibiting their growth.
It is especially used in treating urinary tract infections, caused, for example, by Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
, Proteus
Proteus (bacterium)
Proteus is a genus of Gram-negative Proteobacteria.-Clinical significance:Three species—P. vulgaris, P. mirabilis, and P. penneri—are opportunistic human pathogens. Proteus includes pathogens responsible for many human urinary tract infections. P. mirabilis causes wound and urinary...
, Shigella
Shigella
Shigella is a genus of Gram-negative, nonspore forming, non-motile, rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella causes disease in primates, but not in other mammals. It is only naturally found in humans and apes. During...
, Enterobacter
Enterobacter
Enterobacter is a genus of common Gram-negative, facultatively-anaerobic, rod-shaped bacteria of the family Enterobacteriaceae. Several strains of the these bacteria are pathogenic and cause opportunistic infections in immunocompromised hosts and in those who are on mechanical ventilation...
, and Klebsiella
Klebsiella
Klebsiella is a genus of non-motile, Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. It is named after the German microbiologist Edwin Klebs...
..
It is also a tool in studies as a regulation of bacterial division. It selectively and reversibly blocks DNA replication in susceptible bacteria. Nalidixic acid and related antibiotics inhibit a subunit of DNA gyrase
DNA gyrase
DNA gyrase, often referred to simply as gyrase, is an enzyme that relieves strain while double-stranded DNA is being unwound by helicase. This causes negative supercoiling of the DNA...
and induce formation of relaxation complex analogue. It also inhibits the nicking dosing activity on the subunit of DNA gyrase that releases the positive binding stress on the supercoiled DNA.
It is the only FDA approved quinolone for treating UTI infections in children (3).