Nucleic acid detection method for Chlamydia psittaci based on RPA-CRISPR/Cas12a.

Area of Science:

• Microbiology
• Molecular Diagnostics
• Public Health

Background:

• Chlamydia psittaci (C. psittaci) infections are increasingly linked to severe respiratory illnesses and public health outbreaks.
• Delayed or misdiagnosis of C. psittaci contributes to disease severity and mortality.
• Rapid and accurate detection methods are crucial for timely intervention and effective management of C. psittaci.

Purpose of the Study:

• To develop a rapid, sensitive, and specific nucleic acid detection method for Chlamydia psittaci.
• To establish a Chlamydia psittaci detection assay utilizing the RPA-CRISPR/Cas12a system.
• To evaluate the performance of the developed method compared to qPCR.

Main Methods:

• Designed specific RPA primers and CRISPR RNA (crRNA) targeting the conserved CPSIT_0429 gene of C. psittaci.
• Established a two-step RPA-CRISPR/Cas12a assay and a one-tube variation incorporating glycerol.
• Assessed detection limits, specificity against common respiratory pathogens, and compared results with qPCR.

Main Results:

• The two-step RPA-CRISPR/Cas12a assay achieved a detection limit of 2 × 10° copies/μL.
• The one-tube assay demonstrated a limit of detection of 2 × 10² copies/μL with 20% glycerol.
• The method exhibited high specificity, with no cross-reactivity with influenza virus, SARS-CoV-2, or Streptococcus pneumoniae, and showed high consistency with qPCR results.

Conclusions:

• The RPA-CRISPR/Cas12a system provides a rapid, accurate, sensitive, and specific method for C. psittaci detection.
• This nucleic acid detection platform is suitable for early diagnosis and clinical management of C. psittaci infections.
• The developed assay offers a reliable tool to address the challenges posed by C. psittaci outbreaks.