Basis for a cheap method for detecting bacteria and assessing their antibiotic susceptibility in urine samples

Although molecular methods can now provide fast identification and the antibiotic susceptibility profile of infecting pathogens, these techniques are not affordable by a large majority of clinical laboratories in developing countries and can be considered excessive for simple, community-acquired infections. Most antibiotics are therefore prescribed empirically, which tends to avoid those drugs that face high resistance prevalence but that could still be used in a significant number of patients. This is a description of the basis for a fast, cheap method for assessing the presence of bacterial infection and its susceptibility to antibiotics in body fluids that are normally sterile, such as urine. The method is based on detecting a decreased concentration of glucose in liquid media as an indicator of bacterial growth, and the effect of antibiotics upon this change as an indicator of growth arrest by such antibiotics. The method can assess the presence of ca. 10⁵CFU/mL in 4-6h as well as the presence of antibiotic resistance phenotypes of clinical relevance. The method was tested on 20 clinical urine samples, comparing its results with conventional culture and susceptibility assays; results of both the proposed method and the culture/antibiogram were in agreement in all cases. Materials needed for this method would cost no more than US$5 per assay, it would take 10min to set it up, and only requires a small, fixed-temperature incubator. With minor modifications, it could be much more sensitive and easy to run and/or can provide information on presence of specific bacteria.