A NEW TRIAL FOR BIOFORMATION OF ANTIMICROBIAL AGENT CONTROLLING MULTI DRUG RESISTANT MICROORGANISM

In the present investigation, a trial was done to find a new antimicrobial agent producing microbe from soil microbiota of local habitats to control the problem of multiple drug resistance. The term of Antimicrobial resistance (AMR) is used to describe microorganisms that can resist the effects of drugs and chemicals designed to kill them. Seventy six actinomycetes isolates were isolated from fifteen soil samples different localities in Egypt were primary screening for antimicrobial activity by agar plug diffusion method against test microorganisms. Sixteen isolates were selected for secondary screening in small scale submerged fermentation system and assayed against pathogenic tested microorganisms using agar well diffusion method. Among of these isolates tested, the isolate (S1SHA1) showed the highest antimicrobial activity against pathogenic test organisms. This isolate was identified as Streptomyces griseoplanus by morphological, physiological, biochemical characters and 16s rRNA gene sequence. Physical and nutritional factors affecting activity of antimicrobial agent were studied. The results showed that, optimum activity of antimicrobial agent achieved with pH 7, incubation temperature 28 C, for 7 days, at 150 rpm agitation, carbon and nitrogen source starch 1.5% and potassium nitrate 0.4%, as well as phosphorus 2 g/l and NaCl at concentration of 1 %. Antimicrobial agent from batch culture was subjected to extraction and purification processes using ethyle acetate and preparative TLC, respectively. Determination of minimum inhibitory concentrations (MIC) and Mode of action of antimicrobial agent produced by S. griseoplanus (S1SHA1) on the test microbial strains using Transmission Electron Microscopy (TEM). Cytotoxic studies showed that no cytotoxic effects were observed for the compound when tested even at high concentrations