www.cidrap.umn.edu/all-news
Study ties use of weedkiller to drug-resistant bacteria
News brief
Today at 4:07 p.m.
Chris Dall, MA
Topics
Antimicrobial Stewardship
New research from Argentina suggests a potential link between a commonly used herbicide and antimicrobial resistance (AMR).
In a study published this week in Frontiers in Microbiology, a team led by researchers from the University of Buenos Aires assessed resistance to glyphosate in environmental bacteria from soil and bacteria collected from Argentinian hospitals. Previous studies suggest that exposure to glyphosate, the most widely used herbicide for controlling broadleaf weeds and grasses, can create selective pressure that favors antibiotic-resistant bacterial strains in soil, the study authors explained. But links to clinically relevant pathogens are less clear.
Among the bacterial isolates tested in the study, 68 came from soil in a nature reserve in the Parana delta, which is surrounded by agricultural areas where glyphosate is widely used, and 19 were multidrug-resistant (MDR) bacterial species that commonly cause infections in hospitals, including Enterobacter cloacae.
"Given that opportunistic human pathogens, including MDR strains, can persist in soil, the widespread use of glyphosate in agriculture may favor the selection of clinically relevant resistant bacteria," the study authors wrote.
Unintended side-effects
As expected, the bacteria from the hospitals were resistant to multiple antibiotics, but also highly resistant to glyphosate and glyphosate-based herbicides. The environmental bacteria exhibited ranges of resistance to glyphosate, with the most resistant strains being those related to the hospital strains. For example, environmental isolates in the Enterobacter family tolerated the highest concentrations of the weedkiller.
When the researchers created a family tree of all the bacterial strains, they found that the environmental strains exhibiting the highest resistance to glyphosate clustered closely with the MDR strains from the hospitals. In addition, whole-genome sequencing revealed that the most glyphosate-resistant environmental isolates had a higher number of genetic mechanisms also associated with AMR.
“These results suggest that weedkillers—which, unlike antibiotics, are widely applied in agricultural environments—may have the unintended side-effect of selecting for AMR among bacterial communities within the soil," senior study author Daniela Centron, PhD, said in a journal press release.
While more research is needed, the authors say the findings suggest the AMR dimension should be incorporated into environmental risk assessments of glyphosate and other biocidal agents.
Italy tracks first European human H9N2 avian flu case
News brief
Today at 3:01 p.m.
Stephanie Soucheray, MA
Topics
Avian Influenza (Bird Flu)
The Italian Ministry of Health has confirmed Europe’s first human case of low-pathogenicity avian influenza A(H9N2), in a person from the Lombardy region.
The patient is hospitalized, and was described as being in poor health prior to infection. The patient also came from a non-European country, but it is not clear if he or she was an Italian traveler or a foreign visitor to Italy.
People can contract H9N2 through direct exposure to infected poultry or via contaminated animal environments. Human-to-human transmission has yet to be reported, and human cases typically result in mild illness.
Almost all prior cases detected in China
About 90% of human H9N2 avian flu cases have been reported in China, with detections in Cambodia, Vietnam, and India, as well. Africa has also recorded cases in Egypt, Senegal, and Ghana. The most recent human H9N2 cases reported prior were detected in China in February. Last year there were 29 H9N2 cases reported from mainland China.
According to Avian Flu Diary, an infectious disease tracking blog, some Italian media are reporting the patient is a boy who was in Africa, but that has not been confirmed by the Italian Ministry of Health.
Quick takes: Measles spike in Utah, 5 kids ill from raw milk, CDC director uncertainty
News brief
Today at 2:54 p.m.
Stephanie Soucheray, MA
Topics
E coli
Measles
Public Health
Foodborne Disease
ALL BRIEFS
Study ties use of weedkiller to drug-resistant bacteria
News brief
Today at 4:07 p.m.
Chris Dall, MA
Topics
Antimicrobial Stewardship
New research from Argentina suggests a potential link between a commonly used herbicide and antimicrobial resistance (AMR).
In a study published this week in Frontiers in Microbiology, a team led by researchers from the University of Buenos Aires assessed resistance to glyphosate in environmental bacteria from soil and bacteria collected from Argentinian hospitals. Previous studies suggest that exposure to glyphosate, the most widely used herbicide for controlling broadleaf weeds and grasses, can create selective pressure that favors antibiotic-resistant bacterial strains in soil, the study authors explained. But links to clinically relevant pathogens are less clear.
Among the bacterial isolates tested in the study, 68 came from soil in a nature reserve in the Parana delta, which is surrounded by agricultural areas where glyphosate is widely used, and 19 were multidrug-resistant (MDR) bacterial species that commonly cause infections in hospitals, including Enterobacter cloacae.
"Given that opportunistic human pathogens, including MDR strains, can persist in soil, the widespread use of glyphosate in agriculture may favor the selection of clinically relevant resistant bacteria," the study authors wrote.
Unintended side-effects
As expected, the bacteria from the hospitals were resistant to multiple antibiotics, but also highly resistant to glyphosate and glyphosate-based herbicides. The environmental bacteria exhibited ranges of resistance to glyphosate, with the most resistant strains being those related to the hospital strains. For example, environmental isolates in the Enterobacter family tolerated the highest concentrations of the weedkiller.
When the researchers created a family tree of all the bacterial strains, they found that the environmental strains exhibiting the highest resistance to glyphosate clustered closely with the MDR strains from the hospitals. In addition, whole-genome sequencing revealed that the most glyphosate-resistant environmental isolates had a higher number of genetic mechanisms also associated with AMR.
“These results suggest that weedkillers—which, unlike antibiotics, are widely applied in agricultural environments—may have the unintended side-effect of selecting for AMR among bacterial communities within the soil," senior study author Daniela Centron, PhD, said in a journal press release.
While more research is needed, the authors say the findings suggest the AMR dimension should be incorporated into environmental risk assessments of glyphosate and other biocidal agents.
Italy tracks first European human H9N2 avian flu case
News brief
Today at 3:01 p.m.
Stephanie Soucheray, MA
Topics
Avian Influenza (Bird Flu)
The Italian Ministry of Health has confirmed Europe’s first human case of low-pathogenicity avian influenza A(H9N2), in a person from the Lombardy region.
The patient is hospitalized, and was described as being in poor health prior to infection. The patient also came from a non-European country, but it is not clear if he or she was an Italian traveler or a foreign visitor to Italy.
People can contract H9N2 through direct exposure to infected poultry or via contaminated animal environments. Human-to-human transmission has yet to be reported, and human cases typically result in mild illness.
Almost all prior cases detected in China
About 90% of human H9N2 avian flu cases have been reported in China, with detections in Cambodia, Vietnam, and India, as well. Africa has also recorded cases in Egypt, Senegal, and Ghana. The most recent human H9N2 cases reported prior were detected in China in February. Last year there were 29 H9N2 cases reported from mainland China.
According to Avian Flu Diary, an infectious disease tracking blog, some Italian media are reporting the patient is a boy who was in Africa, but that has not been confirmed by the Italian Ministry of Health.
Quick takes: Measles spike in Utah, 5 kids ill from raw milk, CDC director uncertainty
News brief
Today at 2:54 p.m.
Stephanie Soucheray, MA
Topics
E coli
Measles
Public Health
Foodborne Disease
- Utah officials reported 43 new measles cases in the past week, raising the state total to 486 cases in an outbreak that began last year and shows little signs of slowing down. Almost half, or 233, of the cases are in the Southwest Utah Health District, where the outbreak started. But now the outbreak has spread across much of the state, including 78 cases in Utah County, 53 in Salt Lake County, and 36 in Central Utah. Of the total, 289 cases have been confirmed already this year, compared with 197 for all of 2025.
- Five children from Tennessee have been sickened with Shiga toxin–producing Escherichia coli (STEC) infections after consuming raw milk produced by the same herd of dairy cows. Four of the five children have been hospitalized, and three have developed hemolytic uremic syndrome, which can lead to kidney failure and death. Tennessee law bans the retail sale of raw milk, but it allows residents to buy cows or a herd and consume raw milk from those animals.
- Today marks 210 days since Susan Monarez, PhD, was fired from her position as the director of the US Centers for Disease Control and Prevention (CDC). Federal law dictates that the agency must fill a Senate-confirmed position within 210 days of a vacancy. Currently Jay Bhattacharya, MD, PhD, heads both the CDC and the National Institutes of Health.
ALL BRIEFS