Isolation and PCR detection of rickettsiae from clinical and rodent samples in Malaysia

Area of Science:

• Microbiology
• Infectious Diseases
• Veterinary Medicine

Background:

• Rickettsial infections pose a significant public health concern, particularly in areas with high seroprevalence.
• Understanding the transmission dynamics and sources of rickettsiae is crucial for effective disease control.

Purpose of the Study:

• To investigate the presence of viable rickettsiae in patients' blood and wild rodent organ samples from an area with high rickettsial infection rates.
• To determine if rickettsiae could be successfully isolated and identified using cell culture and animal inoculation methods.

Main Methods:

• Cell culture assays using L929 mouse fibroblast cells inoculated with patient buffy coat.
• Animal passages with mice and guinea pigs infected with wild rodent organ samples.
• Molecular detection using various PCR systems for Orientia tsutsugamushi, typhus, and spotted fever group rickettsiae.

Main Results:

• No rickettsiae were isolated from 48 patient blood samples.
• No symptomatic infections were observed in animals inoculated with 50 wild rodent organ samples.
• Rickettsial DNA was not amplified from any of the tested samples via PCR.

Conclusions:

• The study did not find evidence of active rickettsial infections in the studied patient or wild rodent populations.
• Current diagnostic methods, including cell culture and PCR, failed to detect rickettsiae in the samples collected from this high-seroprevalence area.