Microbial metabolites in the blood of patients with sepsis
© BioMed Central Ltd 2007
Published: 26 September 2007
Molecular mechanisms of the pathophysiology of sepsis remain unknown. Preliminary results allow one to suppose that investigation of biological effects of microbial metabolites, particularly aromatic acids, is one of the most promising methods in elucidation of the problem. These compounds can be produced during microbial fermentation of aromatic amino acids. But little is known of which microorganisms participate in such processes. The aim was to assess the comparative level of aromatic acids in serum of cardiosurgical patients with documentary sepsis and to clarify the in vitro metabolic profile of aromatic acids in spent growth medium of main clinical blood isolates.
Materials and methods
Serum samples were collected from 83 adult subjects (mean age 52 (42–58) years). The main group of investigation consisted of 12 cardiosurgical patients with documentary sepsis, with mortality of 42% (5/12). The comparison groups were: 16 clinically healthy volunteers, 36 patients with acquired heart diseases before surgery, nine patients with smooth recovery on the third day after surgery, 10 patients with pneumonia after surgery. The cultures (n = 32) of S. aureus, S. epidermidis, E. faecalis, K. pneumonia, S. marcesceus, E. coli, E. cloacae, A. baumanii, P. aeruginosa, C. albicans and C. parapsilosis were isolated from the blood of cardiosurgical patients and identified. Concentrations of aromatic acids were determined by gas chromatography–mass spectrometry. Data were compared by Mann–Whitney U-test, P < 0.05 considered significant.
Concentration of aromatic acids in serum sepsis patients and subjects of comparison groups
Aromatic acid (ng/ml)
Patients with sepsis (n = 12)
Volunteers (n = 16)
Patients before surgery (n = 36)
Patients with smooth recovery (n = 9)
Patients with pneumonia (n = 10)
Increased levels of PLA, HPAA and HPLA in serum patients with sepsis, especially with fatal outcome, are associated with development of infectious complications. These compounds are produced by clinically important bacteria, such as K. pneumonia > E. coli > S. aureus > S. marcesceus, E. cloacae, S. epidermidis, but not by fungi. The results can denote biological activity of these microbial metabolites and their influence on pathogenesis of sepsis.