FIG 1.
Association between transmissible beta-lactamase gene DNA copy number and amoxicillin-clavulanate MIC in isolates with no alternative resistance features. Evidence for the association between MIC and log2(DNA copy number) (P < 0.0001, estimated using quantile regression), is presented. The gray line indicates the 2.5 threshold used to define resistance in the extended algorithm based on ROC analysis (see Fig. S3A in the supplemental material). Of these 328 isolates, 294 had blaTEM genes (290 with blaTEM-1, 4 with other non-inhibitor resistant blaTEM genes), 19 had non-inhibitor-resistant blaSHV genes, and 15 had blaCTX-M genes.