456
The bactericidal activity of six new rifamycin derivatives - - rifabutin ( RBU ) , FCE 22250 ( F22 ) , rifapentine ( RPE ) , CGP 29861 ( C29 ) , CGP 7040 ( C70 ) and CGP 27557 ( C27 ) and rifampicin ( RMP ) - - have been measured against log phase and , as a better test of sterilising activity , against stationary phase cultures of Mycobacterium tuberculosis , H37Rv .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
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