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: Based on a score of 8 on the Naranjo adverse drug reaction probability scale , telithromycin was the probable cause of acute hepatitis in this patient , and pathological findings suggested drug - induced toxic hepatitis .
### Output Text:
Based on a score of 8 on the Naranjo adverse drug reaction probability scale , <span class="chemical">telithromycin</span> was the probable cause of acute hepatitis in this patient , and pathological findings suggested drug - induced toxic hepatitis . 