Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 17: 930 - 940. Published May 8, 2009.
Molecular characterization and antibiogram analysis of bacterial community from River Narmada, India
Anjana Sharma*, Varsha Shukla, Roopa Verma and Jyotsn
ABSTRACT
Objectives: To investigate the microbial diversity of unculturable microbes in River Narmada, India, using molecular methods and undertake antibiogram analysis.
Methodology and results: Metagenomic DNA was extracted and cloned into high copy number plasmid vector and transferred to E. coli DH5α, the resulting gene bank was screened for positive clones by growth selection method. The library was then screened for the presence of aminoglycoside resistance genes among the recombinants. Genomic DNA of 10 Kb was obtained and upon preliminary screening, 24 clones expressing resistance to aminoglycoside antibiotics were detected. 1-6 Kb of plasmid DNA was obtained on plasmid profiling. Upon restriction digestion, molecular diversity of 16S rDNA genes showed similarity at 1.5 coefficient levels among the recombinants.
Conclusions and application of findings: Direct cloning method illustrates another way to access and exploit the immense pool of genes from microorganisms. No published reports exist on exploitation of the metagenomic approach to study the microbial diversity of River Narmada. The generation and analysis of (meta) genomic libraries provides a powerful approach to harvest and archive environmental genetic resources. The findings of the present work suggest that the occurrence of antimicrobial resistant bacteria in the aquatic ecosystem of river Narmada may contribute to the environmental dissemination of antibiotic resistance. This fact re-inforces the hypothesis that cultivation independent approach may estimate more accurately the prevalence of antibiotic resistance genes in the environmental samples though it may introduce bias in the recovery of their molecular variants.
Key words: Molecular characterization, antibiogram analysis, bacterial community.
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