TABLE 1

Results of PCR and RFLP for gyrA mutations in S. Typhi and corresponding ciprofloxacin MIC resultsa

Lab. ID no.CountryCIP MIC (μg/ml)Interpretation (S/I/R)PCR-RFLP result (WT or mutated codon[s])
2956Laos0.012SWT
2957Laos0.008SWT
2965Laos0.016SWT
3009Laos0.016SWT
27416Laos0.023SWT
3624Laos0.25I83
3770Laos0.016SWT
2986Laos0.016SWT
27545Laos0.016SWT
3823Laos0.023SWT
27986Laos0.012SWT
27987Laos0.012SWT
28247Laos0.012SWT
28257Laos0.012SWT
28317Laos0.016SWT
28373Laos0.008SWT
28403Laos0.032SWT
28412Laos0.008SWT
3862Laos0.023SWT
3286Cambodia0.5I83, 87
3472Cambodia0.5I83
3473Cambodia0.5I83
3489Cambodia0.5I83, 87
3543Cambodia0.5I83
4402Cambodia0.25I83
  • a Isolates were identified by using the API 20E test (Laos) or an in-house biochemical test set (Cambodia) and Salmonella Omni-O, O9, Vi, and Hd antisera (Pro-lab Diagnostics, United Kingdom) at both sites. Every PCR-RFLP investigation included the following controls to guide interpretation. S83F (gyrA codon 83): nalidixic acid (NA) MIC of 256 μg/ml, ofloxacin (OFX) MIC of 0.38 μg/ml, ciprofloxacin (CIP) MIC of 0.125 μg/ml. D87A (gyrA codon 87): NA MIC of 48 μg/ml, OFX MIC of 0.19 μg/ml, CIP MIC of 0.094 μg/ml. S80I (gyrA codons 83 and 87; parC codon 80): NA MIC of 256 μg/ml, OFX MIC of 16 μg/ml, CIP MIC of 8 μg/ml. S, sensitive; I, intermediate; R, resistant; WT, wild type.