From 1982 to 1985 she received a doctoral scholarship from the Konrad Adenauer Foundation, and from 1986 to 1989 she worked as a research assistant at the University of Osnabrück on publication of Upper German inscriptions for the supplement to the Corpus Inscriptionum Latinarum XIII.
Wealth and Social Status in the Literature of the Principate Period) with the Bruno Heck Science Prize.
Her habilitation thesis on The Letters of Paulinus of Nola: Communication and Social Contacts Between Christian Intellectuals, was funded by the German Research Foundation (DFG).
In 2001/02 she worked with Georg Schöllgen at the Institute for Church History at the University of Bonn in an interdisciplinary DFG project on bishops' legations to the imperial court.
In 2007, Mratschek was elected to the board of the International Patristic Society (Association Internationale d'Études Patristiques).