DOI: 10.3201/eid1601.090896
Suggested citation for this article: Simões RR, Poirel L, Da Costa PM, Nordmann P. Seagulls and beaches as reservoirs for multidrug-resistant Escherichia coli. Emerg Infect Dis. 2010 Jan; [Epub ahead of print]
Seagulls and Beaches as Reservoirs for Multidrug-Resistant Escherichia coli
Roméo Rocha Simões, Laurent Poirel, Paulo Martins Da Costa, and Patrice Nordmann
Author affiliations: Hôpital de Bicêtre, Bicêtre, France (R.R. Simões, L. Poirel, P. Nordmann); and Universidade do Porto, Porto, Portugal (R.R. Simões, P.M. Da Costa)
A variety of extended-spectrum β-lactamase–producing Escherichia coli isolates, with a high rate of cefotaximase-15 resistance, were identified in seagull feces from Porto, Portugal, beaches. Beaches may therefore present a risk to public health because of the potential pathogen-spreading capacity of migratory birds.
The Porto coastline in Portugal, including downtown Porto, has a large seagull population (Larus fuscus, the lesser black-backed gull, and L. cachinnans, the yellow-legged gull). Seagulls have been reported as a possible reservoir for multidrug-resistant bacteria (1). During the past decade, extended-spectrum β-lactamases (ESBL) with growing epidemiologic importance, the cefotaximase (CTX-M) enzymes, have been reported worldwide in Enterobacteriaceae from humans (2); they are found mostly in Escherichia coli. Reasons for the emergence of CTX-M enzymes in human isolates remain unknown. In addition, CTX-M–positive E. coli have been identified in poultry (3), other farm animals (4), and wild animals (birds of prey, foxes [5]). E. coli strains can be classified into 4 phylogenetic groups (A, B1, B2, and D). The virulent extraintestinal isolates belong mostly to group B2 and, to a lesser extent, group D, whereas most commensal strains belong to groups A and B1. The objective of the study was to evaluate the spread and types of ESBL-positive E. coli in feces recovered from wild birds on the beaches of Porto....
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Our report suggests that beaches may play a major role in dissemination of resistance determinants and may be a source of the CTX-M-15–related community-acquired infections. Migratory birds, such as seagulls crossing an extensive portion of the European coastline between Portugal and Scandinavia, may be reservoirs for these emerging resistance determinants.
