Diagnostic Molecular Microbiology and its applications: Current and Future Perspectives

Abstract

Infectious diseases are a major cause of morbidity and mortality throughout the world. Although the field of diagnostic microbiology has substantially evolved over the past few decades, it is still heavily reliant on cultures and serology, which while being cost effective is largely time consuming and sometimes less sensitive and specific. Molecular biology on the other hand has developed with rapid and confirmatory diagnosis. However, the merger of molecular diagnostics in routine diagnostic microbiology labs has been slow paced mostly due to higher costs and lack of infrastructure. Molecular methods have progressed beyond identification to detect antibiotic marker genes, fastidious bacteria, and uncultivable microbes. It has found a scope in mycology and parasitology, in which the basic conventional techniques may sometimes be unable to make a definitive diagnosis of the concerned pathogens. In the field of virology where culturing may be impractical in some clinical settings, it has developed various multiplexing procedures which can detect and quantitate the viral copies present in the crude specimen. Besides the field offers different types of permutations and combinations like direct sequencing for finding the variants, whole genome sequencing, epidemiological testing like plasmid profiling, RFLP etc. which can point out the infection and different types of PCR customisation such as nested, multiplex and Real Time (RT) PCR. In the present review, we have described the various molecular typing techniques and their application in microbial testing with a briefing of the tests that have been already standardised with relevant sample acceptance and rejection criteria for commonly encountered pathogens and pointed towards future directions converging automated closed DNA, RNA extraction/amplification platforms, Next Generation Sequencing (NSG), Microarrays and Digital PCR (dPCR) into its arsenal.