Lab Matters Spring 2022 | Page 27


Mystery Melioidosis : Minnesota ’ s Response to a Rare Outbreak

By Rana Rahmat , specialist , Laboratory Response Network
Melioidosis , also known as Whitmore ’ s Disease , is a highly infectious disease caused by the bacterium Burkholderia pseudomallei . The bacterium is generally found in tropical and subtropical climates and transmission usually involves contact with contaminated soil and water . Those infected can present a wide variety of symptoms such as pneumonia , lesions , sepsis , abscesses or neurological indications .
The United States sees about 12 cases of melioidosis per year , usually associated with travel outside the US to endemic countries . This was not the case in 2021 as there were four cases of melioidosis reported in the US . The cases were spread out over a five-month period between March and July across four different states with the patients having no connection , commonality or travel history outside the US .
Inoculated Sheep Blood Agar plate with Gram-positive Burkholderia pseudomallei incubated for 48 hours . Photo : Oregon State PHL / Larry Stauffer
One of these states was Minnesota , where the third case occurred . The state typically sees one occurrence of Burkholderia infection per year , due to international travel . In this case the clinical laboratory sent samples from the patient , who was admitted to the hospital for the second time on June 6 , to the Minnesota Public Health Laboratory on June 16 . Minnesota tested for Brucella , Francisella , and Burkholderia immediately , by polymerase chain reaction . As soon as the sample was identified as B . pseudomallei on June 16 , 2021 and the results shared with the US Centers for Disease Control and Prevention ( CDC ), the isolate was requested by CDC for immediate sequencing .
Identification was not the end of the laboratory ’ s involvement in the case : buckets of cleaning products and various items also had to be collected , photographed and cataloged prior to being sampled and sent to CDC . The samples were then tested for B . pseudomallei to determine if any of the products had been contaminated .
A key component in the laboratory ’ s response was the existence of the Laboratory Response Network ( LRN ) infrastructure , which provides standardized protocols and guidance for responding to biological threats . Minnesota created the Minnesota Laboratory System ( MLS ) which is a network of the sentinel laboratories within Minnesota ’ s LRN structure . They used its alert system to message all the laboratories in the MLS in the wake of the B . pseudomallei identification . These other laboratories were asked to assess their recent samples and monitor all incoming samples for the biological agent to track any other potential cases .
Success in an outbreak response and investigation is really about persistence and the ability to work with each other , according to former Emergency Preparedness and Response Unit Supervisor Maureen Sullivan . Communication was a key aspect of this success in Minnesota ’ s response to this incident and the subsequent investigation .
“ CDC did a really good job communicating and letting us know where they were in the investigation ,” said Sullivan . This involved frequent conference calls that included the other states providing updates on where they were in the investigation .
It was the hard work and determination of the parties involved that the contaminated product was determined to be the Better Homes and Gardens Essential Oil Infused Aromatherapy Room Spray with Gemstones . The product has since been recalled and the investigation continues to determine which component was contaminated .
Each outbreak , particularly over the last two years , presents its own challenges and learning opportunities for the nation ’ s public health laboratories . According to Sullivan , the impact of this outbreak across the four states was more philosophical , as it is always good to solve problems such as this and to be a part of the outbreak investigation .
“ We can learn good things when we have the opportunity to work together .” •
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