Molecular Epidemiology in Microbiology

REINOSO, ELINA

Advances in Medicine and Biology

Nova Science Publishers Inc.

Año: 2020; p. 122 - 125

A rational and effective strategy to control infections should be directed against clones that cause disease. Besides, it is important to identify sources of contamination and transmission mechanisms. Clonally related organisms are members of the same species that share virulence factors, biochemical and genetic characteristics, and descend from a common precursor cell. However, the existing diversity at the species level means that microorganisms isolated from different sources at different times and in different geographical regions can be differentiated into subtypes. So, to know if two strains are clonally related, is necessary to type them. From the epidemiological point of view, the typing process is important to recognize sources of food outbreaks, detect cross-transmission of nosocomial pathogens, determine the source of infection and recognize virulent strains in order to make epidemiological surveillance and monitor vaccination programs. A variety of phenotypic methods such as phage typing, antibiotic sensitivity, bio-typing, among others, have been widely used to study diversity in epidemiological investigations. However, the high phenotypic variability of the strains has made difficult to adopt these conventional systems. None of these systems used has provided clear and definitive information. Furthermore, results of these techniques are subject to change over the time. These drawbacks have led to the development of new, faster and more reliable techniques, based on DNA technology. Most of the molecular techniques currently used for typing are based on electrophoretic separation of DNA fragments of different molecular weight using agarose gels. This result is represented by a band profile in a gel, where each band is a molecular marker. Thus, related epidemiological isolates will have an indistinguishable genomic profile of unrelated isolates. Molecular epidemiology in the field of infectious diseases points to the detection of genetic polymorphisms, based on measures of genetic heterogeneity, among strains of microorganisms of clinical importance. The knowledge of these relationships is very useful in the area of epidemiology.