Bacteria is a prokaryotic organism having a large number of species. They are present in most of the habitats of earth. Some bacterias are useful while others are pathogenic and even threatful to life. Knowledge of the true bacterial species is fundamental for the effective utilization of that particular species . Most of the bacterias have not been characterized and only some of the species can be grown in labortary. Traditional methods of bacterial identification rely on phenotypic identification using gram staining, culture and biochemical methods. However, these methods of bacterial identification suffer from some drawbacks. The identification and characterization of bacterial species associated with particular traits can be done by using molecular traits.The most common way of molecular characterization of bacteria is by using Polymerase Chain Reaction. This technology allows us to identify any bacterial species to any level of precision by using a single cell. The technology uses molecular probes that bind only to the DNA/RNA of targeted organisms. Bacterial isolates (DNA/RNA) are amplified by Polymerase Chain Reaction and their banding pattern can be visualized by loading the amplified product on visualizing gel and view them under Ultra Violet light. The comparison involves specific regions of DNA between species that can be compared using molecular marker. PCR is the most effective way of identification and characterization as it is independent of external environmental condtions and is least effected by them. It enables investigators to examine bacterial species more deeply and sensitively than culture testing.

PCR is a thermocycler machine which works on the principle of Peltier effect, consisting of cycles of repeated heating and cooling of the reaction for DNA melting and enzymatic replication of the DNA. DNA of specific Bacterial species are isolated and amplified with particular primers. The size at which DNA amplifies helps in the identification of that species. The amplified PCR product can be used for future use in gene cloning, medicine production, DNA footprinting, disease diagnosis etc. With the changing lifestyle habits, it is the need of time to identify useful bacterias (probiotic and prebiotic) and utilize them in our day to day routine. Instead of chemicals and synthetic medicines, bacterias can be used to cure and avoid diseases.With the help of PCR, one single copy of desired bacteria is enough to produce multiple copies. The bacterial species having contrasting characteristics can be recombined using genetic engineering to produce hybrids of interest. Since the identification method is based on PCR, the obtained sensitivity is sufficient to detect low numbers of bacteria. The total time needed for characterization using PCR is less and seems a promising method for the rapid identification of bacteria in usually sterile clinical sites.

Deeksha Jamwal