Availability of 6-hydroxynicotinic acid for rapid identification of pseudomonas aeruginosa and serratia marcescens

Abstract Gas chromatography—mass spectrometry has been used to identify specific metabolites produced by Gram-negative bacteria such as Pseudomonas aeruginosa , Serratia marcescens , Klebsiella pneumoniae and Escherichia coli in a defined medium. 6-Hydroxynicotinic acid was detected in spent culture media of Pseudomonas aeruginosa and Serratia marcescens , but could not be detected in those of Klebsiella pneumoniae and Escherichia coli . The production of 6-hydroxynicotinic acid was recognized by the addition of nicotinic acid in urine with Pseudomonas aeruginosa or Serratia marcescens , but not without the addition of nicotinic acid. Among 10 5 Pseudomonas aeruginosa per 1 ml of urine (criteria for the diagnosis of urinary tract infection), 0.15 μg of 6-hydroxynicotinic acid was detected in urine at 4 h incubation with nicotinic acid at the optimum pH of 6.9, 38°C. The production of 6-hydroxynicotinic acid was proportional to the number of the bacteria and displayed a time dependency. These results suggest that the availability of 6-hydroxynicotinic acid might make for more rapid identification of bacteria than current methods.