Diagnostic Use of PCR in Carbapenamase-producing Enterobacteriaceae (CPE): An Improved Method to Overcome the presence of inhibitors for DNA Extraction from Blood Cultures

BackgroundCarpanenamase-producingEnterobacteriaceae(CPE) has emerged as a threat to hospitalized patients. Phenotypic test such as Modified hodge test was less sensitive and specific especially to detectblaNDM-1 which is the most predominant genotype in this region. Nucleic acid amplification technology offers improved specificity and sensitivity. However, there is limitation in this method which is failed amplification due to the presence of inhibitors. In this study, we try to use previous method described by Villumseen et al with some modification using another DNA extraction kit.Methodology/Principle findingsThree confirmed isolates ofblaNDM-1 carbapenamase-producingKlebsiella pneumoniaewas spiked with 10 mls sterile whole blood in an aerobic Bactec Plus until the growth was detected. The blood specimen was taken and was subjected to DNA extraction method using two commercialized kits followed with multiplex PCR. All the three isolates revealedblaNDM-1 genotypes. Internal control was amplified in all three isolates.Conclusion/significanceThis study proved that we can get a specific and early diagnosis of CPE by using nucleic acid amplification technique directly from blood culture bottle and eliminate the effect of inhibitors.