Although some infections are unique enough to be identified clinically, usually microbiologic laboratory methods are needed to identify the etiologic agent and diagnose microbial infection (Washington, J.A., 1996). Although we have made significant progress in our ability to diagnose and treat infectious diseases, they still remain a strong challenge to human survival, for example the disease Tuberculosis caused by a microbial infection with Mycobacterium tuberculosis accounted for one third of the worlds bacterial infections in 2010 infecting a total of 8.8 million people worldwide (Dheda et al., 2010).
Diagnosis is important not only for prescribing effective drugs but for preventing the evolution of resistant microorganisms (Mori and Notomi, 2009). Traditionally, the microbiology laboratory identified etiologic agents of infectious disease by the direct examination and culture of clinical specimens. Methods of identifying and differentiating microorganisms responsible for microbial infection mainly relied on microbial morphology, staining properties of the organism and its growth variables. However, a major restriction is that >99% of the microorganisms observed through a microscope are not cultivable by these direct techniques (Rastogi and Sani, 2011).
Other disadvantages of these traditional methods include their lack of reproducibility and the difficulties they produce in typing as they are usually not sensitive enough for strain differentiation. These techniques are also restricted by the number of organisms present and the skill of the microbiologist in recognising different pathogens (Tang et al., 1997). Over the past few decades, the development and introduction of molecular-based techniques into the laboratory has resolved many of these issues and has revolutionised the diagnosis of microbial infection.
Nucleic Acid-Based Technologies (NAT)
Since the discovery that microbes were causative agents of numerous infectious diseases in the late 1800s there has been constant work into methodologies to try and detect these infectious agents. Infectious disease is transmissible between individuals and can be detrimental to human existence; because of this technologies used to monitor, prevent and treat these diseases are very important. Successful therapy towards these diseases is usually dependent on rapid detection of the causative agent. Rapid detection leads to faster, more accurate treatment and thus prevents disease progression. This is where molecular-based techniques have revolutionised the diagnosis and treatment of infectious disease. These molecular-based techniques have also revolutionised molecular epidemiology where the source of outbreak infection either in the community or in the hospital can be found and controlled (França et al., 2013). Molecular-based techniques used for microbial infection diagnosis are mainly nucleic acid-based technologies, these involve methods to isolate nucleic acids from...