Introduction

PCRs have revolutionised the detection of bacteria in clinical samples since their widespread introduction in the 1990s.1 Quantitative PCR (qPCR), also known as specific PCR, involves the targeting of particular bacterial species. The technique uses specific primers (short strands of nucleic acid needed to initiate DNA replication) and fluorescent probes to allow real-time quantification of target bacterial DNA during amplification. The qPCR assay is a mainstay of microbiological diagnostics within the National Health Service (NHS). At our hospital approximately 200 qPCRs are performed per week for the investigation of bacterial infections. Although qPCR is by far the most frequently used molecular technique in bacterial diagnostics, in certain scenarios a broad-range (non-specific) 16S rDNA (ribosomal DNA) PCR is increasingly being used. Broad-range 16S rDNA PCR is also more commonly used in research settings, originally for use in detecting and identifying unusual bacterial species but now more widely used in the rapidly expanding field of microbiome research. This technique provides the initial step in the process of analysing complex microbial communities in human, zoological and even geological settings. In the future, analysis of individualised microbial communities using broad-range 16S rDNA PCR may be a key component of personalised medicine.