In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Creatine kinase levels were normal prior to daptomycin therapy and were not reassessed .
### Output Text:
<span class="chemical">Creatine</span> kinase levels were normal prior to <span class="chemical">daptomycin</span> therapy and were not reassessed . 