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: CASE : We describe a second case of fluconazole associated agranulocytosis with thrombocytopenia and recovery upon discontinuation of therapy .
### Output Text:
CASE : We describe a second case of <span class="chemical">fluconazole</span> associated agranulocytosis with thrombocytopenia and recovery upon discontinuation of therapy . 