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: CONCLUSIONS : Children treated with indinavir have a high cumulative incidence of persistent sterile leukocyturia .
### Output Text:
CONCLUSIONS : Children treated with <span class="chemical">indinavir</span> have a high cumulative incidence of persistent sterile leukocyturia . 