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Table 2 IC50 data for benzimidazoles in Ancylostoma caninum isolates

From: Multiple drug resistance in the canine hookworm Ancylostoma caninum: an emerging threat?

IsolateEHA (µM) IC50 (95% CI)EHA IC50 RRLDA (µM) IC50LDA IC50 RREHA (µM) IC95 (95% CI)EHA IC95 RR
ETCR0.23  0.49 
ETCR 1.00.25 0.07 1.13 
Barrow0.24  3.46 
Worthy3.3514.5 10.0720.6
Worthy 1.1F> 36> 100 > 36> 70
Worthy 2.1F2.6511.5 > 36> 70
Barrow 1.00.17 (0.16–0.19) 0.36 (0.28–0.46) 
Worthy 4.1F3P1.02 (0.92–1.12)6.0 14.85 (9.96–23.22)41.3
  1. Notes: ETCR was the susceptible isolate used for calculating resistance ratios in the initial assays and Barrow 1.0 was used for the EHA and ETCR 1.0 for the LDA in subsequent assays. Initial assays were performed singly using ETCR, ETCR 1.0, Barrow, Tara, Lacy, Worthy, Worthy 1.1F and Worthy 2.1F and subsequent assays were performed in triplicate using Barrow 1.0 and Worthy 4.1F3P, in order to improve the precision of the estimate and reduce the width of the 95% confidence intervals (CI). The values for Barrow 1.0 and Worthy 4.1F3P represent the mean IC50 of three biological replicate assays, with each thiabendazole concentration measured in triplicate. IC95 values were also calculated for the EHA. Resistance ratios (RR) were calculated as IC50/95 resistant isolate/IC50/95 susceptible isolate; RR are not provided for the susceptible isolates or where assays were not performed, as this value has no relevance in those instances
  2. Abbreviations: EHA, egg hatch assay; LDA, larval development assay; –, assays not performed