07/01/2021: Lab Alert: Clinical Laboratory Burkholderia pseudomallei Notification

CDC's Laboratory Outreach Communication System (LOCS)

Audience: Clinical Laboratory Professionals

Level: Laboratory Alert

This information is being provided at the request of the CDC subject-matter experts for Burkholderia pseudomallei.

This message is to inform you of an ongoing public health investigation regarding three cases of melioidosis caused by Burkholderia pseudomallei, which occurred in a Kansas resident in March of 2021, a Texas resident in May of 2021, and a Minnesota resident in May of 2021. The isolates from all patients were submitted to CDC for whole genome sequencing which indicated genomic sequences were clonal to one another and were potentially of South Asian origin. None of the patients reported traveling outside of the continental United States. This genomic analysis indicates that these patients were likely exposed to a common source, potentially an imported product or animal, but that source has not been identified to date.

CDC has issued a health alert notification (HAN) to inform physicians about this situation and provide recommendations.

This message to clinical laboratories serves three purposes:

  1. Make laboratories aware of these recent cases of melioidosis and to report other cases that may have been exposed to the same source.
  2. Reduce the potential for laboratory exposures by alerting laboratories about the possibility of B. pseudomallei in their laboratories.
  3. Inform laboratories of the appropriate specimens for receipt, testing to perform, and contacts to notify about suspect specimens.

Notes Regarding Identification of B. pseudomallei:

  • Culture of B. pseudomallei from any clinical specimen is considered diagnostic for melioidosis. Ideal specimens for culture include blood, urine, throat swab, and, when relevant, respiratory specimens, abscesses, or wound swabs. Serological testing is available at CDC for diagnostic testing but is less sensitive and requires paired sera.
  • For additional information on Burkholderia pseudomallei refer to the ASM Sentinel Level Clinical Laboratory Guidelines.
  • Laboratory testing involving automated identification algorithms (i.e., MALDI-TOF, 16s, VITEK-2) may misidentify B. pseudomallei as another bacterium, such as occurred with the case in TX, where the isolate was initially misidentified as Burkholderia thailandensis by MALDI-TOF. Misidentifications may include Burkholderia spp. (specifically B. cepacia and B. thailandensis), Chromobacterium violaceum, Ochrobactrum anthropi, and often Pseudomonas spp., Acinetobacter spp., and Aeromonas spp.
  • Clinical laboratories that have identified any of the agents listed above from hospitalized patients from January 1, 2021, to present should consult with their state or local public health department to determine if referral to a Laboratory Response Network (LRN) laboratory for rule out of B. pseudomallei is indicated.


  • Specimens suspected of containing Burkholderia pseudomallei should be clearly labeled as “suspected Burkholderia pseudomallei
  • When handling specimens suspected to contain B. pseudomallei, increased biosafety practices should be implemented to minimize laboratory exposure. These include:
  1. BSL-2 practices, containment, and facilities should be used when working with clinical specimens suspected of containing B. pseudomallei.
  2. Perform all specimen manipulations within a certified Class II (or higher) Biosafety Cabinet (BSC).Any questions or comments regarding this message should be directed to your state or local public health department.

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Thank you,

The Laboratory Outreach Communication System

Laboratory Outreach Communication System (LOCS) | Division of Laboratory Systems (DLS)

Center for Surveillance, Epidemiology, and Laboratory Services (CSELS)

Centers for Disease Control and Prevention (CDC)