Closer to home: Melioidosis in the United States

Chest Infections & Disaster Response Network

Disaster Response & Global Health Section

Global travel and climactic changes are changing the boundaries for diseases once considered to be geographically limited. Melioidosis, caused by the gram-negative bacillus Burkholderia pseudomallei, does not usually appear on the differential diagnosis of patients in the United States. Historically endemic to South and Southeast Asia, Australia, Puerto Rico, and Central America, B. pseudomallei infects humans via direct inoculation of the skin, through inhalation, or by the ingestion of contaminated soil or water. Importation of melioidosis to the United States from civilian travelers, global commerce, or military personnel is becoming more common (Gee JE, et al. N Engl J Med. 2022;386[9]:861).

A case series of four patients across four states occurred in 2021. Contaminated aromatherapy sprays sold from a retailer whose supplier originated from India were identified as the source (Gee JE, et al). Two additional cases were reported in Mississippi spanning 2 years (CDC Health Alert Network. July 27, 2022). A case in Texas describes the zoonotic detection of the organism in a raccoon carcass (Petras JK, et al. MMWR. 2022;71:1597). Now, cases of U.S. domestic melioidosis have been described, with the CDC identifying areas of the Mississippi Gulf Coast as an endemic region.

The gold standard of diagnosis is the isolation of B. pseudomallei in culture. Serologic tests may also be useful. Automated bacterial identification systems may provide initially inaccurate results, delaying diagnosis and increasing mortality. Presenting symptoms are nonspecific and may resemble typical sepsis syndromes, as well as cavitary lung disease, mimicking TB. The diagnosis requires a high index of suspicion with targeted interviewing.

Clinicians should reevaluate patients with isolates identified as Burkholderia species, especially those who are unresponsive to standard empiric therapies. Treatment for melioidosis involves initial antibiotic therapy with ceftazidime, meropenem, or imipenem, followed by eradication therapy with trimethoprim-sulfamethoxazole or amoxicillin-clavulanate for up to 6 months (Wiersinga WJ, et al. N Engl J Med. 2012;367[11]:1035).

Zein Kattih, MD
Section Fellow-in-Training

Andrew Weber, MD
Section Member-at-Large