Molecular Diagnostics of Infectious Diseases (PDF)

itself, first recognized in 1981, has caused a pandemic that is still in progress. The fragility of public health infrastructures is also characterized by the increasing incidence of nosocomial infections, exemplified by the emergence of Methicillin-resistant Staphylococcus aureus (MRSA) and diarrhea ascribed to Clostridium difficile. Taken together, these events emphasize the variability of infectious disease death rates, the uncertainty of disease emergence and the consequent continued threat to public health.

It is not surprising, then, that tremendous efforts are being made to improve the diagnostics of infectious diseases. The most important feature of an effective diagnostic assay is its capacity for the reliable identification of a targeted pathogen. At the same time, assays should be rapid, uncomplicated and capable of being carried out in the field (‘point-of-care’; POC). Unfortunately, the continued application of legacy assays entails that many ‘gold standard’ diagnostic technologies are slow, expensive, require highly skilled personnel, and are not practical for POC applications. Hence, there is enormous pressure to implement ongoing molecular scientific and technological advances in the development of improved disease surveillance and control systems.

The combination of molecular diagnostics with therapeutics constitutes a key component of integrated healthcare and molecular testing methods have become the strategy of choice for the detection of many infectious diseases. They can provide sensitive and reliable results, detect infectious pathogens both qualitatively and quantitatively and produce rapid test results enabling better and cheaper patient care. Although a qualitative measure of the infectious agent is often sufficient for the detection of many infectious diseases, there are several clinical conditions where the quantification of certain viruses is useful. This is true for measuring viral load in immunosuppressed patients or for monitoring of treatment response. Molecular testing can provide clinicians with faster test results, often measured in minutes, compared with traditional microbiological methods. Combined with a move towards fieldbased, automated, simpler and higher throughput technologies, this development promises to generate a wealth of data establishing organism numbers and types as well as information about virulence and resistance determinants that influence disease severity. This will result in better patient care, translating into improved patient outcome, shortened hospital stays, and reduced cost of antimicrobial treatment.