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: The clinical and autopsy findings in a premature baby who died of acute renal failure after therapy with gentamicin ( 5 mg / kg / day ) and penicillin are presented .
### Output Text:
The clinical and autopsy findings in a premature baby who died of acute renal failure after therapy with <span class="chemical">gentamicin</span> ( 5 mg / kg / day ) and <span class="chemical">penicillin</span> are presented . 