NO2- and NO3- Measurements for Detection of Escherichia coli in Blood Samples

Escherichia (E..) coli, a common causative misroorganism in bacteremia, is a member of facultatively anaerobic bancilli that are able to reduce NO3- to NO2-. To determine whether NO2- production or NO3- reduction occurs during the growth of E.. Coli in blood cultures, NO2- and NO3- were directly and simultaneously neasured by capillary zone electrophoresis. The BACTEC 9240 (Becton Dickinson Diagostic Instrument Systems, USA) was used to culture E. coli cells in blood samples. The NO2- concentration in the medium (6.0±2.6 μM at 0 h) significantly increased at 8 h (ｐ < 0.0001) and lowered to 65.0±37.6 μM at 10h. The peak of NO2- production (9.2±o.7h) appeared earlier than the CO2 production (11.1±0.9h). Theree is no correlation between the peak time of NO2- production and the CO2 detection time (p > 0.05). These data give us an essential potentiality to use the NO2- and NO3- monitoring system for detecting the presence of E. coli cells.

Escherichia coli

capillary zone electrophoresis

bacteremia

CO2 production