Gram positive bacteria especially certain species of staphylococcus are also known to exhibit ability to produce such antimicrobial agents like colicin by E. coli against other strains such as ColN and ColE1 against E. coli F4 (K88) [26, 27]. For E. coli 7, the isolates which showed activity were SD C and PI 2 by forming a clear zone of 11 mm and 10 mm respectively