[Infection with Pseudomonas pseudomallei]

Melioidosis, a severe, often fatal disease caused by infection with Pseudomonas pseudomallei, has been thought to be a rare endemic disease relatively limited to the areas 20 degrees on either side of the equator. However, an increasing number of people travelling to these areas are reportedly suffering from this disease. It is timely to review this disease for doctors who are unfamiliar with this disease. P. pseudomallei, first discovered by Whitmore and Krishnaswami in 1912, is a gram-negative aerobic rod, motile due to polar flagella, isolated from soil and natural waters in endemic areas, and presumably transmitted to human beings through skin abrasion, ingestion and inhalation. Associated underlying conditions must be searched for, such as diabetes mellitus and chronic renal failure. Clinical classification ranges from disseminated septicemic melioidosis, the most serious form, to subclinical melioidosis, the least serious form. Disseminated septicemic type is associated with high fever, multiple organ lesions with septic shock and high fatality rate within a few days after symptoms develop. This type of infection requires prompt institution of antimicrobial therapy as well as surgical intervention such as drainage. Antimicrobial agents should be carefully selected according to the susceptibility results of the isolates. During the suspected stage, ceftazidime is a drug of choice. Subclinical melioidosis associated with positive serologic test alone should be closely followed up against the potential reactivation of dormant infection with P. pseudomallei. We must certainly be aware of melioidosis and diagnose melioidosis as early as possible by completing the initial routine diagnostic procedures to febrile patients.