A method of processing nasopharyngeal swabs to enable multiple testing

Objective To develop a method to perform multiple tests on single nasopharyngeal (NP) swab. Study design We collected a NP swab on children aged 2–12 years with acute sinusitis and processed it for bacterial culture, viruses, cytokine expression, and 16S ribosomal RNA gene sequencing analysis. During the course of the study, we expand the scope of evaluation to include RNA sequencing, which we accomplished by cutting the tip of the swab. Results Of the 174 children enrolled, 126 (72.4%) had a positive bacterial culture and 121(69.5%) tested positive for a virus. Cytokine measurement, as judged by the adequate levels of a housekeeping enzyme (GAPDH), appeared successful. From the samples used for 16S ribosomal sequencing we recovered, on average, 16,000 sequences per sample, accounting for a total of 2,646 operational taxonomic units across all samples sequenced. Samples used for RNA sequencing had a mean RNA Integrity number of 6.0. Cutting the tip of the swab did not affect the recovery yield for viruses or bacteria, nor did it affect species richness in microbiome analysis. Conclusion We describe a minimally invasive sample collection protocol that allows for multiple diagnostic and research investigations in young children.