Identification of capsular serotype and antibiotic resistance (AR) profiles are both important strain features for pneumococcal disease surveillance. Our aim was to expand and validate a multiplex TAC (SPN_TAC) microfluidic platform to identify >90 serotypes, key AR and pilus genes on a single card.
Card included 75 assays designed to accurately identify 57 serotypes, 18 small serogroups, penicillin susceptibility, 2 pili genes and lytA and piaB positive controls for species confirmation. Probes were labelled with two fluorophores, FAM or ABY to detect 2 targets in a single reaction. LOD and specificity was validated with varying DNA concentrations of well characterized S. pneumoniae isolates from CDC’s ABCs collection.
SPN_TAC could accurately identify 57 individual serotypes and 18 small serogroups, penicillin susceptibility, resistance to erythromycin, clindamycin, tetracycline and chloramphenicol and 2 pilus genes. Each assay had high sensitivity of detection (<10 copies/reaction) equivalent to CDC’s multiplex real-time PCR assays.
We developed and validated a highly sensitive multiplex method to identify pneumococcal serotypes/serogroups, key AR determinants and pili genes on a single TAC. The application of TAC for strain characterization of pneumococci allows for simple, fast, high-throughput testing that is suitable for surveillance and outbreak studies for both isolates and sterile-site clinical specimens.