Methods and compositions for detection of drug resistant pathogens and treatment against infections thereof are provided. Methods for detection of oseltamivir-resistant influenza viruses by competitive binding assays utilizing non-oseltamivir influenza virus neuraminidase inhibitors and oseltamivir carboxylate are provided. Influenza virus neuraminidase inhibitors coupled to sensors and useful for employment in the methods of the invention are disclosed. Novel phosphonate compounds active as neuraminidase inhibitors against wild-type and oseltamivir-resistant influenza strains of H1N1, H5N1 and H3N2 viruses are disclosed. An enantioselective synthetic route to preparation of these phosphonate compounds via sialic acid is provided.
