PhD project of Linda Fenske: Streptococcus agalactiae: A potential zoonotic pathogen for humans and cattle

Streptococcus agalactiae, from the streptococcus family, is one of the main triggers of mastitis in cattle as well as occasionally in other mammals. However, S. agalactiae also plays an important role as a human infectious agent, as the main cause of neonatal infections, triggered by transmission from mother to newborn, which can result in pneumonia, meningitis or septicemia.
Recent findings also warn of food borne infections. For example, in Singapore in 2015, there was a cluster of severe infections triggered by the consumption of raw fish. So far, it has not been fully clarified whether this is an original transmission from fish to humans or vice versa. It also remains to be clarified whether transmission of the pathogen from cows to humans or vice versa, for example, during the milking process, is possible and, if so, capable of causing a severe infection.
The occurrence of the same sequence types in different host species definitely supports this, but could as well indicate a common source of infection in the environment.

To elucidate how similar strains of bovine and human origin really are a broad comparative genomic analysis of isolates of different origin is performed. Previous studies have mostly focused on non-holistic methods, usually sequencing only those regions of the genome that are of particular interest. In contrast, a bioinformatic analysis on genome level will be conducted. For this purpose, isolates from cattle affected with mastitis as well as clinical human are compared. The main focus is to address the question of zoonotic potential and to determine how host-specific different strains in fact are.