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PubMed1982

Murein and lipopolysaccharide biosynthesis in synchronized cells of Escherichia coli K 12 and the effect of penicillin G, mecillinam and nalidixic acid.

The incorporation of radioactive N-acetyl-glucosamine into murein and lipopolysaccharide of synchronized cells of Escherichia coli K 12 was followed over 100 min in the presence of antibiotics. At 20 min intervals cell walls were prepared. Lipopolysaccharide and murein sacculi were isolated and the radioactivity was quantified in both polymers. Labelled, newly synthesized murein was characterized according to murein subunits linked to lipoprotein, and the degree of crosslinkage. Furthermore, murein subunits containing anhydromuramic acid were determined, permitting the calculation of the average glycan chain length. The results indicated that penicillin G at 30 micrograms/ml stimulated the incorporation of new murein subunits into sacculi followed by a sudden increase in lipopolysaccharide incorporation into the outer membrane. The degree of crosslinkage in murein synthesized in the presence of 30 micrograms/ml penicillin G was higher than in the control, and almost twice as high as in murein synthesized in the presence of 20 micrograms/ml nalidixic acid. Both antibiotics inhibited cell division at the concentrations indicated. Murein synthesized in the presence of 2 micrograms/ml mecillinam also showed higher crosslinkage. However, about twice as much anhydromuramic acid-containing subunits were observed as in the control. At the same time lipopolysaccharide incorporation into the outer membrane was stimulated two- to three-fold.

Amdinocillin↗
PubMed2004

[Activity of nalidixic acid and fluoroquinolones on Escherichia coli strains isolated from non-complicated urinary infections (reseau TSN - France, 1999 - 2001)].

OBJECTIVE: The authors studied the susceptibility of 1,647 non-repeat isolates of Escherichia coli to quinolones and fluoroquinolones. METHOD: The strains were isolated from non-complicated urinary infections in women 18-64 years of age. Data was provided by the TSN Database France, a real time electronic database which collects antibiotic susceptibility results and patient demographic data. The data was collected from 1999 to 2001 in 63 French hospital laboratories, each using their own routine test methods. Quantitative data was interpreted (S, I, R) according to CA-SFM breakpoint guidelines. RESULTS: Ninety-eight and 94,6 % of the strains were susceptible to ciprofloxacin and nalidixic acid respectively. Cross resistance was assessed as well as intrinsic difference in activity within the fluoroquinolone class. Current fluoroquinolones are still highly efficient, and ciprofloxacin is the most active. CONCLUSION: Since 1996, little change in resistance to fluoroquinolones has been observed. These results confirm the choice of fluoroquinolones as first intention therapy as recommended by consensus conferences.

Adolescent↗
PubMed1985

[Comparative bacteriologic activity of norfloxacin, ofloxacin and pefloxacin against 320 Gram-negative bacilli resistant and non-resistant to nalidixic acid and cephalosporins].

Bacteriostatic and bactericidal effects of three fluoroquinolones, norfloxacin, ofloxacin and pefloxacin, against 320 strains of Gram-negative bacilli were studied in vitro. For nalidixic acid-susceptible Enterobacteriaceae, susceptibility or resistance to second or third generation cephalosporins has no significant bearing on the MIC 90 of each of the three antibiotics. This is not so of nalidixic acid-resistant strains. All E. coli and K. pneumoniae strains are susceptible to the three quinolones (MIC 90 less than 3 mg/1); MICs 90 are higher for E. cloacae and S. marcescens; Serratia strains in particular have an MIC 90 greater than 6 mg/1. Nalidixic acid-susceptible Acinetobacter strains can be eliminated by ofloxacin or pefloxacin, whereas norfloxacin has the greatest activity against P. aeruginosa. We conclude that when multiresistant bacteria emerge, testing of susceptibility to the three quinolones studied may be useful.

Acinetobacter↗
PubMed1976

Inhibition by nalidixic acid of post-uv survival of Escherichia coli.

Nalidixate inhibited the post-uv survival of E. coli B. TAU-bar and Ts-7, but not Bs-1 or B/r when included in the plating medium. Removal of the drug sensitivity by photoreactivation was consistent with pyrimidine dimers as the target for the effect. Nalidixate did not inhibit liquid-holding recovery from uv when included in the holding medium, but survival was inhibited if the drug was in the subsequent plating medium. In fact, there was an actual increase in the number of nonsurvivors due to the drug following a period of holding.

DNA Repair↗
PubMed1977

Mechanism of action of nalidixic acid: purification of Escherichia coli nalA gene product and its relationship to DNA gyrase and a novel nicking-closing enzyme.

A target protein for nalidixic and oxolinic acids in Escherichia coli, the nalA gene product (Pnal), was purified to homogeneity as judged by gel electrophoresis, using an in vitro complementation assay. It is a dimer of identical 110,000-dalton subunits. A polypeptide of this molecular weight is uniquely induced by a lambda nalA transducing phage, thereby showing that the purified Pnal is a product of the nalA gene. Nalidixic and oxolinic acids inhibit DNA gyrase activity and induce formation of a relaxation complex analogue. Treatment of the complex with sodium dodecyl sulfate causes a doublestrand break in the DNA substrate and the resulting linear molecule seems covalently bound to protein. Complex formation, unlike the introduction of supertwists, does not require ATP or relaxed circular DNA and is insensitive to novobiocin. DNA gyrase from a strain with a nalA mutation conferring drug resistance (nalA(r)) is 1/100 as sensitive to oxolinic and nalidixic acids with respect to inhibition of supertwisting and induction of the pre-linearization complex. Addition of Pnal restores drug sensitivity and stimulates DNA gyrase activity. DNA gyrase preparations and Pnal catalyze a third reaction sensitive to nalidixic and oxolinic acids, the ATP-independent relaxation of supertwister DNA. Relaxation by gyrase from nalA(r) cells is drug resistant. The nicking-closing activity is distinct from E. coli omega protein in several properties, including the ability to relax positively supertwisted DNA. We postulate that the nalA gene product occurs in two molecular forms, as Pnal and as a gyrase component. Both forms catalyze nicking-closing, and inhibition of this activity by nalidixic and oxolinic acids may account for the inhibition of DNA synthesis by these drugs.

Bacterial Proteins↗
PubMed1970

Nalidixic acid.

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Costs and Cost Analysis↗