1963
Penicillinase - resistant penicillins remain essential antibiotics in the treatment of severe infections caused by Staphylococcus aureus due to their bactericidal activity , safety , and cost .
 Chemical: penicillins
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: penicillins