Research, Antimicrobial Resistance

More than 50% of Seagulls Analysed in Barcelona are Carriers of 'E.coli' Bacteria Resistant to Several Antibiotics

The results highlight the potential role of migratory birds in the spread of antibiotic resistance genes

Photo: Jörg Hempel

A team led by Jordi Vila, director of the Antimicrobial Resistance Initiative in ISGlobal, in collaboration with Dr. Montalvo and his group from the Barcelona Public Health Agency (ASPB), has found antibiotic resistant E. coli bacteria in more than 50% of samples obtained from yellow-legged gulls in Barcelona.  The results show, for the first time, the coexistence of two carbapenemases and confirm the potential role of migratory birds in the spread of antibiotic resistance genes

The number of bacteria presenting resistance to several antibacterial drugs has increased dramatically over the last decades, in great part due to the abuse and misuse of antibiotics for human and animal use. Once drug-resistant bacteria emerge, they can spread globally as a result of factors including international travel, globalization of commercial food, and migratory birds. Faecal samples from gulls contain high levels of E. coli, and Spain is the European country with the highest number of gull E. coli isolates resistant to more than one antibiotic.    

In this study, the authors investigated the prevalence of genes that confer resistance to beta-lactams (broad spectrum antibiotics) among E. coli isolates obtained from seagulls. To do so, they analysed 132 faecal samples obtained from gull chicks from different nests distributed across the city. They found that more than half of the isolates (54.5%) were positive for antibiotic resistance genes, with a predominance of extended-spectrum beta-lactamases (51%). Furthermore, they identified for the first time the presence of carbapenemases in two gull isolates.    

“Our data show that the prevalence of drug-resistant E. coli in gull faecal samples is higher than we thought” explains Jordi Vila. “The fact that the two carbapenem-resistant isolates share sequences with strains recovered from human samples in different parts of the world, highlights the role of these birds in the dissemination of antibiotic resistance genes” he adds.   

More information:

The Four Battlefronts in the War against Antibiotic Resistance


Vergara A, Pitart C, Montalvo T, Roca I, Sabaté S, Hurtado JC, Planell R, Marco F, Ramírez B, Peracho V, de Simón M, Vila J. Prevalence of Extended-Spectrum-β-Lactamase- and/or Carbapenemase-Producing Escherichia coli Isolated from Yellow-Legged Gulls from Barcelona, Spain. Antimicrob Agents Chemother. 2017 Jan 24;61(2).