7951
Among them , compounds 26 - 28 showed the most potent activity ( 0 . 25 , 0 . 03 and 2 mu g / ml ) against S . pneumoniae expressing the erm gene , the mef gene and the erm and mef genes , respectively .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None