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: Aza patients had significantly more staphylococcal infections than all other transplant groups ( P less than 0 . 005 ) , and systemic fungal infections occurred only in the liver transplant group .
### Output Text:
<span class="chemical">Aza</span> patients had significantly more staphylococcal infections than all other transplant groups ( P less than 0 . 005 ) , and systemic fungal infections occurred only in the liver transplant group . 