Integration of Group A Streptococcus Rapid Tests with the Open Fluidic CandyCollect Device

Area of Science:

• Biotechnology and Medical Diagnostics
• Microbiology and Infectious Diseases

Background:

• Traditional pharyngeal swabs for Group A Streptococcus (GAS) detection can be uncomfortable for users, particularly children.
• Rapid antigen detection tests (RADTs) offer quick results but rely on effective sample collection methods.

Purpose of the Study:

• To evaluate the CandyCollect, a lollipop-inspired oral fluid device, as a user-friendly alternative for sample collection in GAS RADTs.
• To optimize a protocol for integrating the CandyCollect device with existing RADT kits for GAS detection.

Main Methods:

• Developed and optimized an elution protocol for oral fluid samples collected with the CandyCollect device for use with RADT kits.
• Conducted *in vitro* experiments using spiked saliva to determine optimal reagents and elution volumes for RADT readout.
• Validated the optimized protocol using clinical samples from pediatric patients diagnosed with GAS pharyngitis.

Main Results:

• The CandyCollect device coupled with RADT successfully detected *Streptococcus pyogenes* at concentrations as low as 1.5 × 10⁵ CFU/mL.
• Image analysis of lateral flow assay (LFA) strips provided objective quantification of test results.
• Four out of six pediatric patients with confirmed GAS pharyngitis showed positive results using the CandyCollect-integrated RADT.

Conclusions:

• The CandyCollect device is a viable and comfortable alternative for oral fluid sample collection in GAS RADTs.
• The optimized protocol demonstrates the potential of CandyCollect for accurate and user-friendly detection of GAS infections in clinical settings.