Study Finds Seagulls May Spread Resistant Bacteria
Over the last decade, antibiotic resistance has become a serious issue in fighting virulent bacteria. Scientists worldwide have worked to determine specific factors that cause bacteria to develop this virulence against antibiotics, and how those factors are spread. A study, led by Miller School physicians, has found that seagulls and pelicans on Miami Beach may be among the birds carrying one of the most frequently found resistance genes (CTX-M-15) among community patients.
The study, “Wild Coastline Birds as Reservoirs of Broad Spectrum β-Lactamase-Producing Enterobacteriaceae in Miami Beach, Florida,” is published in the May edition of the journal Antimicrobial Agents and Chemotherapy.
CTX-M-15 is not only one of the most frequent genes causing broad spectrum resistance in enteric organisms, those that live in the intestines, but also is the predominant gene associated with resistant E. coli causing urinary tract infections in women.
In 2009, a similar study in Portugal led by the first author of this study, Laurent Poirel, Ph.D., Department of Bacteriology-Virology, Hospital of Paris, made a similar finding in seagulls along the coast of Portugal. Under the leadership of Silvia Munoz-Price, M.D., associate professor of medicine in the Division of Infectious Diseases, a team of University of Miami researchers looked for the same determinants in the stool of seagulls in Miami Beach.
Their results showed that 14 percent of the seagulls sampled carried this resistant E. coli, expressing CTX-M-15, the same strain found infecting humans with urinary tract infections. It’s unclear if the seagulls became infected from the humans or the humans were infected from the seagulls.
What is clear, Munoz-Price points out, is that seagulls now represent an animal reservoir for resistant organisms. “This paper is significant because it highlights the importance of the environment and wild animals as potential sources of transmission of resistant organisms within our communities.”
The study was conducted by Carolina de la Cuesta, M.D., fellow in Infectious Diseases, who collected stool samples for an entire month, in collaboration with Timothy J. Cleary, Ph.D., professor of pathology and director of the Clinical Microbiology Laboratory at Jackson Memorial Hospital. The study was also done in collaboration with colleagues from France, Poirel’s microbiology team.
Researchers point out that seagulls and other birds can easily spread drug-resistant factors worldwide just by drinking contaminated water and sifting through garbage, then flying several hundred miles.
CTX-M-15 producing E. coli has spread all over the world causing community acquired infections. Scientists don’t know how this has happened, but certainly environmental and animal reservoirs could have contributed to this explosive spread.
Munoz-Price, who is also medical director of Infection Control at Jackson Memorial Hospital, says, “That’s why it’s always a good idea to shower immediately after going to the beach.”