Molecular diagnostics is an increasing popular approach for the direct detection and identification of pathogenic bacteria in clinical samples. Conventional culture techniques are time-consuming and therefore causing a delay in the diagnosis of the patient. Alternative techniques based on nucleic acid amplification offer a shorter turn-around-time and the ability to identify fastidious and non-cultivable organisms. However, molecular detection of bacteria in blood, by for example PCR, RT-PCR, or sequencing of the 16S rDNA genes is often complicated by the presence of PCR-inhibitory compounds. Here we describe several different methods for the extraction of bacterial DNA from whole blood samples. The methods differ regarding costs, hands-on time as well as regarding sensitivity. In combination with a model PCR the detection limits that can be reached using the different methods range from 1,000 to 50 cfu/ml.
|Series||Methods in Molecular Biology|