TXN and infection: However, a recent study from USA [97] has reported the essential role of the multigene locus encoding a single, fused methionine sulfoxide reductase (MsrAB) and thioredoxin (Trx)- and cytochrome c (CcdA)-like proteins in attachment and colonization of F. nucleatum to the placental tissues, thereby expediting the initiation of infection and its spread to the amniotic fluid.