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: The case of a 40 - year - old patient who underwent an unsuccessful cadaver kidney transplantation and was treated with ethambutol and isoniazid is reported .
### Output Text:
The case of a 40 - year - old patient who underwent an unsuccessful cadaver kidney transplantation and was treated with <span class="chemical">ethambutol</span> and <span class="chemical">isoniazid</span> is reported . 