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: We report the first case of a serious short - term adverse reaction with the use of omeprazole : hemolytic anemia .
### Output Text:
We report the first case of a serious short - term adverse reaction with the use of <span class="chemical">omeprazole</span> : hemolytic anemia . 