Transmission of antimicrobial resistant Yersinia pestis during a pneumonic plague outbreak

  • Known for the infamous Black Death, plague continues to affect hundreds of people globally each year in underdeveloped countries.

  • An antimicrobial resistant (AMR) strain of Yersinia pestis was discovered from a 2013 Madagascar pneumonic plague outbreak.

  • Newly published research from Dave Wagner and colleagues, reveals for the first time that AMR Y. pestis can be transmitted person to person.






Plague killed tens of millions of people during the infamous Black Death in the 14th century. It has been virtually eradicated in the developed world, yet still affects hundreds of people globally each year. When bubonic plague infections (caused by the bacterium Yersinia pestis) go untreated, the infection can progress and spread to the lungs, causing pneumonic plague.. Typically lethal if not treated, patients with pneumonic plague can transmit the disease to others via respiratory droplets.


Scientists consider plague a reemerging and neglected disease, especially in the East African island country of Madagascar. With no vaccine, preventing deaths requires rapid diagnosis, followed by treatment with antibiotics. The publication shows that an antimicrobial resistant (AMR) strain of Y. pestis – resistant to the antibiotic streptomycin – was isolated from a 2013 Madagascar pneumonic plague outbreak.


A team of scientists from Northern Arizona University led by professor Dave Wagner from the Pathogen and Microbiome Institute conducted a study of this outbreak together with colleagues at the Institut Pasteur de Madagascar, the Institut Pasteur Paris, and the Madagascar Ministry of Public Health. The results of the study, “Transmission of antimicrobial resistant Yersinia pestis during a pneumonic plague outbreak,” were recently published in the journal Clinical Infectious Diseases.


The outbreak involved 22 cases including three fatalities. Using epidemiology, clinical diagnostics, and DNA-fingerprinting approaches, they discovered that AMR strains of Y. pestis can be transmitted person-to-person. This AMR strain is resistant to streptomycin due to a spontaneous point mutation but is still susceptible to many other antibiotics, including co-trimoxazole.


Luckily, the 19 cases all survived after receiving co-trimoxazole in addition to streptomycin. The point mutation, also the source of streptomycin resistance in other bacterial species, has occurred independently in Y. pestis at least three times and appears to have no negative effect on the fitness of the AMR strain. This suggests that it could potentially persist in nature via the natural rodent-flea transmission cycle. However, AMR Y. pestis strains are exceedingly rare and the mutation has not been observed again in Madagascar since this outbreak.


Researchers at PMI are trained and equipped to study dangerous pathogens like plague and COVID-19, to develop cures and treatments that prepare us for future global pandemics.




About Northern Arizona University

Northern Arizona University is a high-research institution providing exceptional educational opportunities in Arizona and beyond. NAU delivers a student-centered experience to its nearly 30,000 students in Flagstaff, statewide, and online through rigorous academic programs in a supportive, inclusive, and diverse environment. Dedicated, world-renowned faculty help ensure students achieve academic excellence, experience personal growth, have meaningful research opportunities, and are positioned for personal and professional success. 


About The Pathogen & Microbiome Institute

The Pathogen & Microbiome Institute (PMI) is a multi-disciplinary research center at Northern Arizona University in Flagstaff. We perform cutting-edge research on both pathogenic and commensal microbes, with the goal of advancing the human condition through the careful application of state of the art microbial and genomic science. PMI is committed to undergraduate and graduate student research training in an internationally-recognized world-class facility. We have over 100 faculty, full time staff, graduate and undergraduate students working with domestic and international collaborators to conduct experiments that define the future of pathogen research.


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