Pseudomonas pseudomallei: II. Laboratory and experimental studies in animals

Area of Science:

• Microbiology
• Infectious Diseases

Background:

• Melioidosis is a serious infection caused by Pseudomonas pseudomallei.
• Understanding the organism's characteristics is crucial for diagnosis and treatment.

Purpose of the Study:

• To describe the cultural, biochemical, and antibiotic sensitivity profiles of Pseudomonas pseudomallei strains.
• To investigate the pathogenicity of a specific strain in a guinea pig model.

Main Methods:

• Isolation and characterization of Pseudomonas pseudomallei from melioidosis patients.
• Antibiotic sensitivity testing (chloramphenicol, tetracycline, colimycin, gentamicin).
• Pathogenicity studies in guinea pigs via intraperitoneal inoculation and cutaneous abrasion.

Main Results:

• Pseudomonas pseudomallei identified as gram-negative bacilli with distinctive colony morphology and odor.
• All isolates sensitive to chloramphenicol; most sensitive to tetracycline.
• All isolates resistant to colimycin and gentamicin.
• Guinea pig model demonstrated acute septicemia with large inocula and chronic infection with small inocula, leading to multi-organ abscesses.

Conclusions:

• Pseudomonas pseudomallei exhibits unique characteristics aiding identification.
• Chloramphenicol and tetracycline show potential as treatment options, while colimycin and gentamicin are ineffective.
• The guinea pig model effectively replicates acute and chronic melioidosis, highlighting the bacterium's diverse pathogenicity.