Rapid Detection of Fosfomycin Resistance in Escherichia coli

The rapid fosfomycin/Escherichia coli NP test was developed to detect fosfomycin resistance in E. coli isolates. The test is based on glucose metabolization and the detection of bacterial growth in the presence of fosfomycin at 40 mu g/ml. Bacterial growth is visually detectable by an orange-to-yellow color change of red phenol, a pH indicator. A total of 100 E. coli isolates, among which 22 were fosfomycin resistant, were used to evaluate the test performance. The sensitivity and specificity of the test were 100% and 98.7%, respectively. This new test is user friendly, sensitive and specific, and its results are obtained in 1 h 30 min.