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: Here , we report two cases of severely immunocompromised HIV - infected patients who developed severe intrahepatic cholestasis , and in one patient lesions mimicking liver abscess formation on radiologic exams , during co - trimoxazole treatment for PCP .
### Output Text:
Here , we report two cases of severely immunocompromised HIV - infected patients who developed severe intrahepatic cholestasis , and in one patient lesions mimicking liver abscess formation on radiologic exams , during <span class="chemical">co - trimoxazole</span> treatment for PCP . 