Relapsed Melioidosis Model in C57BL/6 Mice.

Area of Science:

• Infectious Diseases
• Immunology
• Microbiology

Background:

• Melioidosis, caused by Burkholderia pseudomallei, frequently relapses in endemic regions.
• The precise mechanisms driving melioidosis relapse remain poorly understood.

Purpose of the Study:

• To establish a model of relapsed melioidosis in C57BL/6 mice.
• To investigate the role of immune suppression in B. pseudomallei infection relapse.

Main Methods:

• C57BL/6 mice were infected with B. pseudomallei strains (wild-type and biofilm mutant).
• Immune suppression was induced using hydrocortisone at day 60 post-infection.
• Histopathology and bacterial counts assessed inflammatory responses and bacterial dissemination.

Main Results:

• Infected mice exhibited significant mononuclear cell infiltration by day 60.
• Immune suppression led to high blood bacterial counts for both strains.
• Both wild-type and biofilm mutant strains induced relapse, with wild-type causing more severe inflammation.

Conclusions:

• Reduced immune status can precipitate relapsed melioidosis in individuals with chronic inflammation.
• B. pseudomallei persistence and host immune response are critical factors in disease relapse.