Melioidosis cases in Georgia, Minnesota, Texas, Kansas “most closely related to strains found in Asia, particularly South Asia”: What is the epi-link?

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By Daniel R. Lucey MD, MPH, FIDSA

On Aug. 9, the U.S. Centers for Disease Control and Prevention reported both in their Health Alert Network and in a separate media statement a fourth case of melioidosis in the United States. This patient lived in Georgia and died in July 2021. The common exposure epidemiological (epi-) link that connects these four persons is still an enigma.

That an epi-link does exist is suggested by the fact that CDC reported in the media statement that genomic analysis demonstrated that all four strains of the Burkholderia pseudomallei “appear most closely related to strains found in Asia, particularly South Asia, even though none of the patients traveled internationally.”

Melioidosis is not usually considered contagious. Clinical laboratory workers should be advised if this bacteria is suspected, however, due to a risk of infection if it is aerosolized in the clinical laboratory.

CDC “believes the most likely cause is an imported product” given that this bacteria has not been found in more than 100 samples tested from products, soil and water from inside and near the U.S. patients’ homes. The four states with one proven case between March and July are Kansas, Minnesota, Texas and Georgia.

Two of the four patients have died. No autopsy results have been published so far, nor have antibiotic susceptibility profiles been reported to see if all four isolates are identical and to guide clinicians treating future patients in 2021.

A review article on melioidosis in South Asia was published in June 2018 in Tropical Medicine Infectious Diseases by Mukhopadhyay and colleagues.

Three potential avenues to consider to solve the epi-link enigma ASAP include:

  1. Looking for unrecognized cases starting in all states with proven cases, such as by asking clinicians, clinical and reference laboratories and health departments to alert CDC to any unidentified gram-negative isolates or isolates any time in 2021 of the multiple bacteria that CDC lists in their HAN June 30 and Aug. 9 that can be misidentified as B. pseudomallei (e.g., B. thailandensis, B. cepacian, Chromabacterium violaceum, Ochronobactrum anthropi and possibly others).
  2. Reporting the antibiotic susceptibility profile of this typically multidrug-resistant bacteria and comparing with U.S. and global databanks of cases from South Asia AND cases imported from South Asia into, for example, the Middle East and elsewhere in 2020-2021.
  3. Performing serosurveys to measure antibody levels against B. pseudomallei in the persons and geographic areas close to these four patients in four states (so far). It is not plausible to me that these are the only four patients with melioidosis in the U.S. in 2021. More exist and will be found in 2021 if the search is comprehensive.

Dr. Daniel Lucey

Daniel Lucey, MD, MPH, FIDSA, FACP, is a Clinical Professor of Medicine at Dartmouth Geisel School of Medicine, Infectious Disease adjunct Professor at Georgetown Medical Center, senior scholar at Georgetown Law, Anthropology Research Associate at the Smithsonian Museum of Natural History and a member of the Infectious Diseases Society of America Global Health Committee. He served as a volunteer to outbreaks overseas including hands-on Ebola patient care in Sierra Leone and Liberia (Doctors without Borders) 2014, MERS 2013, SARS 2003, as well as HIV, H5N1, Zika, yellow Fever, and pneumonic plague 2017 (with WHO/USAID/CDC). Since Jan. 6, 2020 he has contributed more than 100 posts to Science Speaks on COVID-19 and traveled to China in February 2020. He initially proposed, then fundraised and helped design the content for 2018-2022 Smithsonian Exhibition on Epidemics due to zoonotic viruses. From 1982-1988 he trained at University of California San Francisco and Harvard and was an attending physician at the NIH (NIAID) in the 1990s while in the U.S. Public Health Service.

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