10787
The mode of resistance to quinupristin / dalfopristin was not evident ( sat A - negative by PCR ) ; and these cases illustrate the existence of streptogramin - resistant isolates before the introduction of this antimicrobial class into human clinical practice .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
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