هاي مختلف PH اثرات ضديتي برخي از باكتريهاي فلورطبيعي روده با يكديگر در

The Study of Antagonistic Effects of Some Intestinal Normal Flora on Each Other at Different pHs

Excessive usage of broad-spectrum antibiotics may provide a favorable background for growth of antibiotic resistant bacteria by devasting normal microflora. Application of indigenous microorganisms (normal flora) for prevention or treatment of some infections is an acceptable practice. In the present study, we investigated the antagonistic effects of E-coli on a number of other intestinal normal flora. In this study, 100 strains of E-coli were isolated from 1000 fecal samples and their antagonistic effects on the growth of Enterobacter, Proteus and Morganella were determined by flip streak assay and synchronous cross streaking in different pHs, ranging from 5 to 9. We observed the inhibitory effects of E-coli isolates on Proteus and Morgaenellaʹs growth in synchronous cross streaking at nearly neutral pH. Therefore it can be concluded that the above inhibitory effect may be influenced by different pHs and that E-coli has no effect on Enterobacterʹs growth.