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: Other antibacterial agents that showed associations included erythromycins ( 2 defects ) , penicillins ( 1 defect ) , cephalosporins ( 1 defect ) , and quinolones ( 1 defect ) .
### Output Text:
Other antibacterial agents that showed associations included <span class="chemical">erythromycins</span> ( 2 defects ) , <span class="chemical">penicillins</span> ( 1 defect ) , <span class="chemical">cephalosporins</span> ( 1 defect ) , and <span class="chemical">quinolones</span> ( 1 defect ) . 