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 describe a case of a patient with Staphylococcal IE who developed acute renal failure secondary to a segmental necrotising glomerulonephritis while being treated with rifampicin , and review the literature regarding this complication of rifampicin therapy .
### Output Text:
We describe a case of a patient with Staphylococcal IE who developed acute renal failure secondary to a segmental necrotising glomerulonephritis while being treated with <span class="chemical">rifampicin</span> , and review the literature regarding this complication of <span class="chemical">rifampicin</span> therapy . 