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: Nafcillin was discontinued and daptomycin 9 mg / kg daily was initiated for suspected meningitis and was continued until the patient ' s death on day 16 .
### Output Text:
<span class="chemical">Nafcillin</span> was discontinued and <span class="chemical">daptomycin</span> 9 mg / kg daily was initiated for suspected meningitis and was continued until the patient ' s death on day 16 . 