Original Research Article
Year: 2019 | Month: May | Volume: 9 | Issue: 5 | Pages: 312-321
Antimicrobial Potential of Soil Isolates from Uttarakhand Region against Pathogens and Drug Resistant Strains
Kavita Sharma
Professor & Head, Dept. of Botany, Govt. A&C Girls College, Raipur, Chhattisgarh, India
ABSTRACT
Soil is the major repository of microbes that produce antibiotics. The soil is dominantly an ecosphere of different microbes comprising pathogenic bacterial and fungal strains along with beneficial and antibiotic producing microbes. The antibiotic producers are of great concern to the biotech and pharmaceutical industry. The antibiotics are of major utility as these are the molecules secreted by one microbe to invade the function of another microbe. The antibiotics are also broadly categorized under the category known as “defensins”. The antibiotics secreted by the positive antibiotic producers are able to inhibit the growth of pathogenic microbes. The present study is about the investigation of twelve isolates from different soil samples i.e only one isolate was obtained from Garden soil (Sample A), seven isolates were obtained from Near the Banks of Ganga River (Sample B) and four isolates were obtained from soil sample from local gardens (Sample C) of Uttarakhand. The isolates were named as R/D on the basis of site of location (say Rishikesh and Dehradun) to avoid ambiguity on the culture plates and slants. The isolates were maintained on Nutrient agar plates and slants. The isolates were further screened for gram staining and different biochemical tests. The results showed that amongst twelve isolates obtained, 6 were gram positive bacilli, 3 were gram negative bacilli and 3 were gram positive cocci. The antimicrobial activity of the supernatant/ethyl acetate fraction and pellet fractions of bacteria isolates was determined by well diffusion method against the selected bacterial and fungal pathogens. The pellets of the isolates was rinsed in N-saline and later evaluated for antimicrobial effect while the supernatant/was taken as such for evaluation of antimicrobial activity. The results showed that, supernatant/ethyl acetate fraction and pellet fraction of the isolates possessed antimicrobial activity. It was found that E. coli NCIM 2065, Lactobacillus plantarum NCIM 2083, Micrococcus luteus ATCC 9341, Salmonella abony NCIM 2257 and MRSA 8 (isolated from pus) were the most resistant pathogens which showed no activity against supernatant/ethyl acetate fraction of any of the isolates of soil samples collected from Rishikesh and Dehradun regions of Uttarakhand. Only B2 supernatant/ethyl acetate fraction showed significant antibacterial activity against MRSA 35 (isolated from blood). Fractions, B1-B7 and C1-C4 showed antifungal activity against Candida albicans NCIM 3471 and Aspergillus niger NCIM 1196. The results indicate that E. coli NCIM 2065, Salmonella abony NCIM 2257, MRSA 8 (isolated from pus) and MRSA 35 (isolated from blood) were the most resistant pathogens which showed no activity against pellet fraction of any of the isolates. The pellet fractions B2, C2 and B6 showed antibacterial activity against Micrococcus luteus ATCC 9341. The pellet fractions, A1, B5, B6, C1 and C6 showed antibacterial activity against Lactobacillus plantarum NCIM 2083. The pellet fractions, A1, B2 and B3 showed antifungal activity against Aspergillus niger NCIM 1196 while Candida albicans NCIM 3471 was found to be sensitive against B1, B2, B5 and B6 pellet fractions. The supernatant/ethyl acetate fractions of the potent isolates, B2, B5 and C2 were analyzed by thin TLC plate using chloroform and methanol (60:40) as solvent system and erythromycin as control/standard antibiotic. Each extract produced spots when the chromatogram was visualized under iodine vapor. The spot was near the solvent front with Rf value of 0.54 for B2, 0.56 for B5 and 0.57 for C2. Standard antibiotic, Erythromycin however formed a tailed spot with Rf of about 0.5.
Key words: Soil isolates, antibiotic producers, antibiotic, pathogens and drug resistant strains, Uttarakhand region (Rishikesh and Dehradun).