NITRATE-REDUCING BACTERIA IN DIVERSION COLITIS - A CLUE TO INFLAMMATION

A pathogenic role of nitric oxide has been suggested in acute and chro nic intestinal inflammation. We took the opportunity offered by studie s in patients with excluded colon, which represents a model of chronic intestinal inflammation with no exogenous nitrite or nitrate supply, to evaluate the quantity and the quality of nitrate reducers in divers ion colitis, Thirty patients (17 men, 13 women, mean age 45 years) hav ing an excluded colon for various reasons were sampled by rectal swabs and compared to 30 healthy controls (11 men, 19 women, mean age 28 ye ars). The percentage of nitrate-reducers among the total count of subc ultured bacteria was 46 +/- 41% (mean +/- SD) in patients with diversi on colitis as compared to 19 +/- 24% in healthy controls. This differe nce was significant (P < 0.05) despite great heterogeneity in individu al values, In patients with diversion colitis, 75/254 (29.5%) differen t isolated bacterial strains were nitrate-reducers as compared to 61/2 94 (21%) (P < 0.05) in controls, Among the 75 nitrate-reducing strains isolated from patients with diversion colitis, 55 were aerobes, Pseud omonas species were only encountered in this population. The predomina nt group was enterobacteria with a high isolation rate of species belo nging to the genera Proteus, Providencia, and Morganella. In healthy c ontrols nitrate-reducing anaerobes were nearly as frequent as aerobes. The most frequent species was Eubacterium lentum, followed by Clostri dium perfringens. It could be suggested that nitric oxide synthase mig ht produce a bacterial substrate increasing the growth of bacteria wit h a high pathogenic potential, creating conditions for chronic inflamm ation and infection in patients with excluded colon.