23838
In this study we investigated the relationship between several selected commercially available essential oils and beta - lactam antibiotics on their antibacterial effect against multidrug resistant bacteria .
 Chemical: beta - lactam
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: beta - lactam