16S Ribosomal RNA PCR Versus Conventional Diagnostic Culture in the Investigation of Suspected Bacterial Keratitis

PURPOSE: The purpose of this study was to compare conventional diagnostic culture (CDC) to 16S ribosomal RNA polymerase chain reaction (PCR) analysis for diagnosing bacterial keratitis. METHODS: Samples collected from 100 consecutive patients presenting to the Royal Liverpool University Hospital with bacterial keratitis were processed using CDC and 16S PCR analysis. RESULTS: The overall detection rate using both methods was 36%. Of these, 72.2% (26/36) were detected by PCR and 63.9% (23/36) isolated by CDC (P = 0.62). Using a combination of both PCR and CDC increased the detection rate for pathogenic bacteria by 13% compared to using CDC alone (P = 0.04). In CDC negative samples, 16S PCR identified more pathogens than CDC in 16S PCR negative samples. Neither order of sample collection nor prior antimicrobial use affected the detection rate. CONCLUSIONS: 16S rRNA gene PCR performed in addition to CDC on corneal samples from patients with clinically suspected bacterial keratitis led to additional pathogen detection. TRANSLATIONAL RELEVANCE: 16S rRNA gene PCR should be developed to become an additional part of clinical service for patients with bacterial keratitis rather than used in isolation.