Quick PCR based diagnosis of typhoid using specific genetic markers

Area of Science:

• Molecular Biology
• Microbiology
• Infectious Diseases Diagnostics

Background:

• Typhoid fever, caused by Salmonella typhi, remains a significant global health concern.
• Current diagnostic methods often involve lengthy culture-based procedures.
• There is a critical need for rapid and accurate diagnostic tools for early intervention.

Purpose of the Study:

• To develop a swift multiplex polymerase chain reaction (PCR) assay for the early detection of typhoid fever.
• To identify and utilize specific genetic markers of Salmonella typhi for enhanced diagnostic accuracy.
• To reduce the time required for typhoid diagnosis compared to existing methods.

Main Methods:

• Development of a multiplex PCR assay targeting specific genes (tyv, flag, viaB, ratA) of Salmonella typhi.
• Direct use of serum samples from suspected typhoid patients without prior culturing or genomic DNA isolation.
• Validation of primer specificity and PCR sensitivity using known concentrations of genomic DNA.

Main Results:

• The developed multiplex PCR method achieved a diagnosis time of only 2 hours, a significant reduction.
• The assay demonstrated high sensitivity, detecting as little as 5 fg of genomic DNA.
• The chosen genetic markers and primers specifically amplified and differentiated Salmonella typhi from closely related species like Salmonella typhimurium.

Conclusions:

• A rapid, sensitive, and specific multiplex PCR method for early typhoid diagnosis has been successfully established.
• This technique bypasses traditional culture methods, offering a substantial time advantage.
• The assay's ability to differentiate S. typhi from S. typhimurium enhances its clinical utility for accurate typhoid diagnosis.