¹H NMR spectroscopy in the diagnosis of Klebsiella pneumoniae-induced urinary tract infection

The ¹H NMR spectroscopic method is suggested and its utility is demonstrated for the diagnosis of Klebsiella pneumoniae (K. pneumoniae) in urinary tract infection (UTI). K. pneumoniae have the specific property of metabolizing glycerol to 1,3-propanediol (1,3-PD), acetate, ethanol and succinate. The quantity of 1,3-PD produced correlates well with the viable bacterial count. Other common bacteria causing UTI (except for Citrobacter frundii), such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Enterobacter aerogenes, Acinetobacter baumanii, Proteus mirabilis, Enterococcus faecalis, Streptococcus gp B and Staphylococcus aureus do not metabolize glycerol under similar conditions. Citrobacter frundii (C. frundii) also gives the same NMR results but is easily differentiated as being motile on direct microscopic examination of urine and it is not common nosocomial infectious agent in urinary tract infection. The method provides a single-step documentation of K. pneumoniae (and C. frundii) qualitatively as well as quantitatively. Out of the total 614 subjects considered, clinical diagnosis of UTI was obtained in 516 cases (84%). The NMR-based screening had a sensitivity of 90%, a specificity of 100% and a false negativity of 10% relative to the conventional quantitative culture method. In the present authors' experience, the results of NMR spectroscopy based screening show a very good correlation with the diagnosis of urinary tract infected patients.