In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

Let me give you an example: Sox - 4 is important for very early B - cell differentiation , while TCF - 1 / LEF - 1 play a crucial role in early thymocyte development 
The answer to this example can be: TCF - 1
Here is why: The gene, TCF - 1 has been tagged as protein since it plays a crucial role in early thymocyte development.

OK. solve this:
 Twenty - four hour time - kill curves for penicillin in combination with various aminoglycosides were performed by Dr . Robert Moellering on the S . faecium isolated from the patient ' s blood immediately prior to mitral valve excision and replacement ( Fig . 1 ) .
Answer:
S . faecium