Outsourced workers of the Universitätskliniken Schleswig-Holstein (university hospitals Schleswig-Holstein UKSH) went on a 48h warning strike from April 21 to 22.
The strikers were demanding the same wage as the workers employed by the parent company. They want to earn wages based on the Public Service Wage Agreement since their empoyer, the outsourced Stern Nord GmbH is a hundred-percent subsidiary of the UKSH, a hospital group in public domain.

Similarily to subsidiaries of other hospital companies in public domain such as Vivantes and Charité in Berlin, the Nord Stern GmbH was established to enable public wage dumping.
With the effect that colleagues in lower pay grades, "depend on having a second job", according to union secretary Stephan Hofmann.

The employees are organised in the Union of Service Workers (Gewerkschaft der Servicekräfte GDS) that was founded out of a grassroots initiative, "since Verdi did nothing" (from the video). (Verdis behaviour during a strike of colleagues of the Vivantes subsidiary VSG is documented here [in German]).

The GDS has its own Vimeo channel, with a beautiful mobilisation clip in which the workers call their fellows to strike [in German].

Here's way to the UKSH blog at netzwerkIT [in German].