A Review of Melioidosis Cases in the Americas.

Melioidosis is a bacterial infection caused by Burkholderia pseudomallei, a gram-negative saprophytic bacillus. Cases occur sporadically in the Americas with an increasing number of cases observed among people with no travel history to endemic countries. To better understand the incidence of the disease in the Americas, we reviewed the literature, including unpublished cases reported to the Centers for Disease Control and Prevention. Of 120 identified human cases, occurring between 1947 and June 2015, 95 cases (79%) were likely acquired in the Americas; the mortality rate was 39%. Burkholderia pseudomallei appears to be widespread in South, Central, and North America.

Melioidosis Cases and Selected Reports of Occupational Exposures to Burkholderia pseudomallei--United States, 2008-2013.

PROBLEM/CONDITION: Melioidosis is an infection caused by the Gram-negative bacillus Burkholderia pseudomallei, which is naturally found in water and soil in areas endemic for melioidosis. Infection can be severe and sometimes fatal. The federal select agent program designates B. pseudomallei as a Tier 1 overlap select agent, which can affect both humans and animals. Identification of B. pseudomallei and all occupational exposures must be reported to the Federal Select Agent Program immediately (i.e., within 24 hours), whereas states are not required to notify CDC's Bacterial Special Pathogens Branch (BSPB) of human infections. PERIOD COVERED: 2008-2013. DESCRIPTION OF SYSTEM: The passive surveillance system includes reports of suspected (human and animal) melioidosis cases and reports of incidents of possible occupational exposures. Reporting of suspected cases to BSPB is voluntary. BSPB receives reports of occupational exposure in the context of a request for technical consultation (so that the system does not include the full complement of the mandatory and confidential reporting to the Federal Select Agent Program). Reporting sources include state health departments, medical facilities, microbiologic laboratories, or research facilities. Melioidosis cases are classified using the standard case definition adopted by the Council of State and Territorial Epidemiologists in 2011. In follow up to reports of occupational exposures, CDC often provides technical assistance to state health departments to identify all persons with possible exposures, define level of risk, and provide recommendations for postexposure prophylaxis and health monitoring of exposed persons. RESULTS: During 2008-2013, BSPB provided technical assistance to 20 U.S. states and Puerto Rico involving 37 confirmed cases of melioidosis (34 human cases and three animal cases). Among those with documented travel history, the majority of reported cases (64%) occurred among persons with a documented travel history to areas endemic for melioidosis. Two persons did not report any travel outside of the United States. Separately, six incidents of possible occupational exposure involving research activities also were reported to BSPB, for which two incidents involved occupational exposures and no human infections occurred. Technical assistance was not required for these incidents because of risk-level (low or none) and appropriate onsite occupational safety response. Of the 261 persons at risk for occupational exposure to B. pseudomallei while performing laboratory diagnostics, 43 (16%) persons had high-risk exposures, 130 (50%) persons had low-risk exposures, and 88 (34%) persons were classified as having undetermined or unknown risk. INTERPRETATION: A small number of U.S. cases of melioidosis have been reported among persons with no travel history outside of the United States, whereas the majority of cases have occurred in persons with a travel history to areas endemic for melioidosis. If the number of travelers continues to increase in countries where the disease is endemic, the likelihood of identifying imported melioidosis cases in the United States might also increase. PUBLIC HEALTH ACTIONS: Reporting of melioidosis cases can improve the ability to monitor the incidence and prevalence of the disease in the United States. To improve prevention and control of melioidosis, CDC recommends that (1) physicians consider melioidosis in the differential diagnosis of patients with acute febrile illnesses, risk factors for melioidosis, and compatible travel or exposure history; (2) personnel at risk for occupational exposure (e.g., laboratory workers or researchers) follow proper safety practices, which includes using appropriate personal protective equipment when working with unknown pathogens; and (3) all possible occupational exposures to B. pseudomallei be reported voluntarily to BSPB.

Contact investigation of melioidosis cases reveals regional endemicity in Puerto Rico.

BACKGROUND: Melioidosis results from infection with Burkholderia pseudomallei and is associated with case-fatality rates up to 40%. Early diagnosis and treatment with appropriate antimicrobials can improve survival rates. Fatal and nonfatal melioidosis cases were identified in Puerto Rico in 2010 and 2012, respectively, which prompted contact investigations to identify risk factors for infection and evaluate endemicity. METHODS: Questionnaires were administered and serum specimens were collected from coworkers, neighborhood contacts within 250 m of both patients' residences, and injection drug user (IDU) contacts of the 2012 patient. Serum specimens were tested for evidence of prior exposure to B. pseudomallei by indirect hemagglutination assay. Neighborhood seropositivity results guided soil sampling to isolate B. pseudomallei. RESULTS: Serum specimens were collected from contacts of the 2010 (n = 51) and 2012 (n = 60) patients, respectively. No coworkers had detectable anti-B. pseudomallei antibody, whereas seropositive results among neighborhood contacts was 5% (n = 2) for the 2010 patient and 23% (n = 12) for the 2012 patient, as well as 2 of 3 IDU contacts for the 2012 case. Factors significantly associated with seropositivity were having skin wounds, sores, or ulcers (odds ratio [OR], 4.6; 95% confidence interval [CI], 1.2-17.8) and IDU (OR, 18.0; 95% CI, 1.6-194.0). Burkholderia pseudomallei was isolated from soil collected in the neighborhood of the 2012 patient. CONCLUSIONS: Taken together, isolation of B. pseudomallei from a soil sample and high seropositivity among patient contacts suggest at least regional endemicity of melioidosis in Puerto Rico. Increased awareness of melioidosis is needed to enable early case identification and early initiation of appropriate antimicrobial therapy.

Fatal Burkholderia pseudomallei infection initially reported as a Bacillus species, Ohio, 2013.

A fatal case of melioidosis was diagnosed in Ohio one month after culture results were initially reported as a Bacillus species. To identify a source of infection and assess risk in patient contacts, we abstracted patient charts; interviewed physicians and contacts; genetically characterized the isolate; performed a Burkholderia pseudomallei antibody indirect hemagglutination assay on household contacts and pets to assess seropositivity; and collected household plant, soil, liquid, and insect samples for culturing and real-time polymerase chain reaction testing. Family members and pets tested were seronegative for B. pseudomallei. Environmental samples were negative by real-time polymerase chain reaction and culture. Although the patient never traveled internationally, the isolate genotype was consistent with an isolate that originated in Southeast Asia. This investigation identified the fifth reported locally acquired non-laboratory melioidosis case in the contiguous United States. Physicians and laboratories should be aware of this potentially emerging disease and refer positive cultures to a Laboratory Response Network laboratory.