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Table 1 Quinolone-specific resistance mechanisms in 2005 and 2009 nalidixic acid-resistant isolates

From: Rapid evolution of fluoroquinolone-resistant Escherichia coli in Nigeria is temporally associated with fluoroquinolone use

Number of isolates Nalidixic acid MIC Ciprofloxcin GyrA SNPs ParC SNPs Horizontally-acquired
2005      
3 8-32 Sensitive S83L - -
1 1024 Resistant S83L, D87N S80I -
2009      
2 256 Sensitive D101G* - -
1 16 Sensitive S83L - -
1 1024 Resistant S83L, D87N - -
4 > 1024 Resistant S83L, D87N S80I -
1 64 Sensitive - S94F* -
1 256 Sensitive - V54I* -
1 32 Resistant - Y74C* qnrS1
5 16-256 Resistant - - qnrS1
  1. *Previously unreported SNP for which there is no evidence of functional contribution to resistance