SummaryThe difficulties encountered in measuring the susceptibility ofthe association amoxicillin/clavulanate can be a cause for disagreements between laboratories. With an inoculum standardized at H)4CFU/spot, the resistance level ofE. coliapproaches 10 %. If the variety of current methods is taken intoaccount.theevaluation of a resistance increase can only be an internal one, specific for each laboratory, provided that methods do not change in the course of time.