Broad-range PCR as a supplement to culture for detection of bacterial pathogens in patients with a clinically diagnosed spinal infection

Abstract

We aimed to evaluate broad-range PCR and subsequent sequencing compared to conventional culture in the diagnosis of spinal infection. The method was a prospective study of all patients admitted to Aarhus University Hospital for surgery during a 12-months period with a clinically diagnosed infection of the spine. Samples from patients undergoing surgery for non-infectious causes (malignancy etc.) were included as control group. Specimens were submitted to conventional culture and molecular investigation with 16S rRNA gene amplification and sequence analysis. 38 patients were included in the study (clinically diagnosed spinal infections=18; non-infectious diseases=20). The specificity was excellent for both culture and PCR (95% and 100%, respectively). A true culture positive result was obtained in 50% of patients (9/18) and 61% was positive (11/18) by broad-range PCR. When combined, culture and PCR allowed for a microbiological diagnosis in 72% of patients (13/18). A positive culture was found only in patients treated ≤7 d compared to ≤16 d for PCR. However, PCR and culture result were equally negatively affected by duration of treatment. The combination of culture and broad-range PCR substantially adds to the number of microbiological diagnoses obtained, and improves the clinician's opportunity to tailor therapy to individual patients.