Table 1

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

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

*Previously unreported SNP for which there is no evidence of functional contribution to resistance

Lamikanra et al. BMC Infectious Diseases 2011 11:312   doi:10.1186/1471-2334-11-312