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: In vivo evidences suggesting the role of oxidative stress in pathogenesis of vancomycin - induced nephrotoxicity : protection by erdosteine .
### Output Text:
In vivo evidences suggesting the role of oxidative stress in pathogenesis of <span class="chemical">vancomycin</span> - induced nephrotoxicity : protection by <span class="chemical">erdosteine</span> . 