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Multistate Outbreak of Salmonella Infections Linked to Kratom (Final Update)

Posted May 24, 2018 4:00 PM ET


This outbreak investigation is over. People should be aware that kratom could be contaminated with Salmonella and could make people sick. Contaminated products may still be available for purchase because the investigation was not able to identify a single, common source of contaminated kratom. Illnesses could continue to occur if people consume contaminated kratom. Read more on the Recalls and Advice to Consumers webpage.

Highlights

  • Read the Recalls and Advice to Consumers>>
  • As of May 24, 2018, this outbreak investigation is over.
  • People should be aware that kratom could be contaminated with Salmonella and could make people sick. Contaminated products may still be available for purchase because the investigation was not able to identify a single, common source of contaminated kratom.
    • Several companies recalled kratom products because they might be contaminated with Salmonella. The list of recalled kratom products is available on the U.S. Food and Drug Administration website.
    • Kratom is also known as Thang, Kakuam, Thom, Ketom, and Biak.
    • Kratom is a plant consumed for its stimulant effects and as an opioid substitute.
  • CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration investigated this multistate outbreak of Salmonella infections.
    • A total of 199 people infected with the outbreak strains of Salmonella were reported from 41 states.
    • Thirty-eight percent of ill people were hospitalized, and no deaths were reported.
    • This outbreak included infections from several types of Salmonella: Salmonella I 4,[5],12:b:-, Salmonella Heidelberg, Salmonella Javiana, Salmonella Okatie, Salmonella Weltevreden, and Salmonella Thompson.
  • Epidemiologic and laboratory evidence indicated that kratom was the likely source of this multistate outbreak.

Outbreak Summary

Introduction

CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) investigated this multistate outbreak of Salmonella infections.

Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting was performed on Salmonella bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. WGS gives a more detailed DNA fingerprint than PFGE.

As of May 24, 2018, 199 people infected with the outbreak strains of Salmonella were reported from 41 states. A list of the states and the number of cases in each can be found on the Case Count Map page.

Illnesses started on dates ranging from January 11, 2017 to May 8, 2018. Ill people ranged in age from less than 1 to 75 years, with a median age of 38. Among ill people, 52% were male. Of 132 people with available information, 50 (38%) were hospitalized. No deaths were reported.

Whole genome sequencing analysis did not identify any predicted antibiotic resistance in isolates from 111 ill people and 61 kratom samples. Testing of 17 clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also did not show any antibiotic resistance.

Investigation of the Outbreak

Epidemiologic and laboratory evidence indicated that kratom was the likely source of this multistate outbreak. Kratom is a plant consumed for its stimulant effects and as an opioid substitute.

State and local health officials interviewed ill people to ask about the foods they ate and other exposures before they became ill. Seventy-six (74%) of 103 people interviewed reported consuming kratom in pills, powder, or tea. Most people reported consuming the powder form of kratom. People who reported consuming kratom purchased it from retail locations in several states and from various online retailers.

This outbreak was detected when a cluster of people infected with Salmonella I 4,[5],12:b:- was identified by CDC PulseNet. During the investigation, health and regulatory officials in several states and the FDA collected various leftover and unopened kratom products to test for Salmonella contamination. As additional strains of Salmonella were identified in kratom products, a search of the CDC PulseNet database identified ill people infected with some of these strains, including Salmonella Heidelberg, Salmonella Javiana, Salmonella Okatie, Salmonella Weltevreden, and Salmonella Thompson. These ill people were added to the outbreak investigation. Eighty-five different DNA fingerprints of Salmonella bacteria were identified in samples of kratom products. The FDA website has a list of contaminated kratom products, which were from several retail locations and online retailers. Several companies issued recalls of kratom products. A list of the recalled kratom products is also available on the FDA website.

This outbreak investigation is over. However, some kratom products that were contaminated with Salmonella have not yet been recalled and may still be available for purchase or in people’s homes. People who are at risk of severe Salmonella infection should avoid consuming kratom to prevent infection.

Previous Outbreak Announcements

April 5, 2016

Case Count Update

Since the last update on March 15, 2018, 45 more ill people from 19 states were added to this investigation.

As of April 5, 2018, a total of 132 people infected with outbreak strains of Salmonella I 4,[5],12:b:- (61), Salmonella Javiana (15), Salmonella Okatie (21), or Salmonella Thompson (35) have been reported from 38 states. A list of the states and the number of cases in each can be found on the Case Count Map page.

Illnesses started on dates ranging from January 11, 2017, to March 20, 2018. Ill people range in age from 1 to 73 years, with a median age of 38. Fifty-four percent of ill people are male. Of 96 people with available information, 38 (40%) have been hospitalized. No deaths have been reported.

Illnesses that occurred after March 14, 2018, might not yet be reported due to the time it takes between when a person becomes ill with Salmonella and when the illness is reported. This takes an average of 2 to 4 weeks.

Whole genome sequencing analysis did not identify any predicted antibiotic resistance in isolates from 60 ill people and three Kratom samples. Testing of eight clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also did not show any resistance.

Investigation Update

State and local health officials continue to interview ill people to ask about the foods they ate and other exposures before they became ill. Fifty-seven (73%) of 78 people interviewed reported consuming kratom in pills, powder, or tea. Most people report consuming the powder form of kratom. People who reported consuming kratom purchased it from retail locations in several states and from various online retailers.

Despite the information collected to date about where ill people purchased kratom, a single common brand or supplier of kratom has not been linked to the outbreak. CDC continues to recommend that people not consume kratom in any form because it could be contaminated with Salmonella and could make people sick. This investigation is ongoing and we will provide updates as needed.

March 15, 2018

Case Count Update

Since the last update on March 2, 2018, 47 more ill people from 25 states were added to this investigation.

As of March 14, 2018, a total of 87 people infected with outbreak strains of Salmonella I 4,[5],12:b:- (50), Salmonella Javiana (5), Salmonella Okatie (16), or Salmonella Thompson (16) have been reported from 35 states. A list of the states and the number of cases in each can be found on the Case Count Map page.

Illnesses started on dates ranging from January 21, 2017 to February 24, 2018. Ill people range in age from 6 to 67 years, with a median age of 39. Fifty-five percent of ill people are male. Of 69 people with available information, 27 (39%) have been hospitalized. No deaths have been reported.

Illnesses that occurred after February 20, 2018, might not yet be reported due to the time it takes between when a person becomes ill with Salmonella and when the illness is reported. This takes an average of two to four weeks.

WGS analysis did not identify any predicted antibiotic resistance in isolates from 47 ill people and two Kratom samples. Testing of four clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also did not show any resistance.

Investigation Update

Since the last update on March 2, 2018, investigators identified ill people infected with other types of Salmonella, including Salmonella Okatie, Salmonella Javiana, and Salmonella Thompson. Epidemiologic and laboratory evidence has linked these additional Salmonella illnesses to consuming kratom.

Health officials continue to collect various leftover and unopened kratom products to test for Salmonella contamination. Investigators in California collected leftover Phytoextractum brand kratom powder from an ill person in that state. The outbreak strain of Salmonella I 4,[5],12:b:- was identified in this sample. As a result of these findings, PDX Aromatics recalled kratom powder sold online between January 18, 2018 and February 18, 2018.

Investigators in Oregon and Utah collected kratom powder from retail locations and online retailers where ill people reported purchasing kratom. Outbreak strains of Salmonella Okatie and Salmonella Thompson were identified in these samples. No brand information was available for the kratom products collected in Oregon. The ill person in Utah purchased kratom powder from the website kratoma.com.

State and local health officials continue to interview ill people to ask about the foods they ate and other exposures before they became ill. Forty (73%) of 55 people interviewed reported consuming kratom in pills, powder, or tea. Most people report consuming the powder form of kratom. People who reported consuming kratom purchased it from retail locations in several states and from various online retailers.

Despite the information collected to date about where ill people purchased kratom, a single common brand or supplier of kratom has not been linked to the outbreak. At this time, CDC recommends that people not consume any brand of kratom in any form because it could be contaminated with Salmonella and could make people sick. This investigation is ongoing and we will provide updates as needed.

March 1, 2018

Case Count Update

Twelve more ill people from seven states were added to this investigation since the last update on February 20, 2018.

As of February 28, 2018, 40 people infected with the outbreak strain of Salmonella I 4,[5],12:b:- have been reported from 27 states. A list of the states and the number of cases in each can be found on the Case Count Map page.

Illnesses started on dates ranging from October 10, 2017 to February 13, 2018. Ill people range in age from 6 to 67 years, with a median age of 41. Sixty percent of ill people are male. Of 31 people with available information, 14 (45%) have been hospitalized. No deaths have been reported.

Illnesses that occurred after February 6, 2018, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of two to four weeks.

Whole genome sequencing (WGS) analysis did not identify any predicted antibiotic resistance in bacteria isolated from five ill people. Testing of one clinical isolate using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory did not show any resistance.

Investigation Update

Health officials are collecting various leftover and unopened kratom products to test for Salmonella contamination. The North Dakota [PDF – 2 pages] and Utah departments of health collected leftover kratom powder from ill people in their states. The outbreak strain of Salmonella I 4,[5],12:b:- was identified in both samples. The ill person in North Dakota purchased S.K. Herbalist brand kratom powder from the website soapkorner.com. The ill person in Utah purchased kratom powder from the website kratoma.com.

State and local health officials continue to interview ill people to ask about the foods they ate and other exposures before they became ill. Seventeen (71%) of 24 people interviewed reported consuming kratom in pills, powder, or tea. Most people report consuming the powder form of kratom. For the 17 people who reported consuming kratom, 13 remembered where it was purchased. Three people reported purchasing kratom from retail locations in several states and 10 people reported purchasing kratom from various online retailers.

Despite the information collected to date about where ill people purchased kratom, a single common brand or supplier of kratom has not been linked to the outbreak. At this time, CDC recommends that people not consume kratom in any form because it could be contaminated with Salmonella and could make people sick. CDC’s recommendation may change as more information becomes available. This investigation is ongoing and we will provide updates as needed.

Initial Announcement

February 20, 2018

CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) are investigating a multistate outbreak of Salmonella I 4,[5],12:b:- infections.

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on Salmonella bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. WGS gives a more detailed DNA fingerprint than PFGE.

As of February 16, 2018, 28 people infected with the outbreak strain of Salmonella I 4,[5],12:b:- have been reported from 20 states. A list of the states and the number of cases in each can be found on the Case Count Map page. WGS performed on isolates from ill people were closely relatedly genetically. This means that people in this outbreak are more likely to share a common source of infection.

Illnesses started on dates ranging from October 13, 2017 to January 30, 2018. Ill people range in age from 6 to 67 years, with a median age of 41. Sixteen people are male. Eleven hospitalizations have been reported. No deaths have been reported.

This outbreak can be illustrated with a chart showing the number of people who became ill each day. This chart is called an epidemic curve, or epi curve. Illnesses that occurred after January 23, 2018, might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.

WGS analysis did not identify any predicted antimicrobial resistance in isolates from five ill people. Testing of outbreak isolates using standard antibiotic susceptibility testing methods is currently underway in CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory.

Investigation of the Outbreak

Epidemiologic evidence indicates that kratom is a likely source of this multistate outbreak. Kratom is a plant consumed for its stimulant effects and as an opioid substitute. Kratom is also known as Thang, Kakuam, Thom, Ketom, and Biak.

In interviews, ill people answered questions about the foods they ate and other exposures in the months before they became ill. Eight (73%) of 11 people interviewed reported consuming kratom in pills, powder, or tea. No common brands or suppliers of kratom have been identified at this time.

At this time, CDC recommends that people not consume kratom in any form. The investigation indicates that kratom products could be contaminated with Salmonella and could make people sick. CDC’s recommendation may change as more information becomes available. This investigation is ongoing and we will provide updates as needed.

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