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: DISCUSSION : Telithromycin is the first of the ketolide antibacterials to receive US Food and Drug Administration approval for clinical use .
### Output Text:
DISCUSSION : <span class="chemical">Telithromycin</span> is the first of the ketolide antibacterials to receive US Food and Drug Administration approval for clinical use . 