Authors: Romano-Bertrand S, Baranovsky S, Licznar-Fajardo P, Jumas-Bilak E (Université de Montpellier, France)
The monomicrobial pathogen paradigm evolves towards the pathobiome concept
In the 19th century, Robert Koch defined pathogens and thereby laid the foundations of infectiology. At the end of 20th century, Koch’s postulate was reinterpreted on molecular basis [1,2].
Strict and specific pathogens generally fulfil Koch’s criteria but the behavior of opportunistic pathogens is only partially explained by either classical or molecular postulates. The reason is primarily due to the absence of true virulence factors with a single genetic determinant in opportunistic bacterial pathogens (OBPs), which instead express pathoadaptive behaviors . In addition, while the infection generally corresponds to the uncontrolled proliferation of a single pathogen, its dynamics involves complex and multiple microbial interactions between pathogen and host microbiota or environmental communities, promoted by favoring conditions. Classical medical microbiology is based on the isolation of the pathogenic bacteria responsible for the infection in monomicrobial culture, however, next-generation approaches have to be much more integrative by considering biotic interactions along with the abiotic conditions of the infection.