Carriage of CTX-M type extended spectrum β-lactamases (ESBLs) in gulls across Europe.

Johan Stedt,Björn Olsen,Barry J Mcmahon,Jorge Hernandez,Conny Tolf,Jonas Waldenström,Jonas Bonnedahl,Mirva Drobni

doi:10.1186/s13028-015-0166-3

Abstract

BackgroundExtended spectrum β-lactamases (ESBLs), a group of enzymes conferring resistance to third generation cephalosporins have rapidly increased in Enterobacteriacae and pose a major challenge to human health care. Resistant isolates are common in domestic animals and clinical settings, but prevalence and genotype distribution varies on a geographical scale. Although ESBL genes are frequently detected in bacteria isolated from wildlife samples, ESBL dissemination of resistant bacteria to the environment is largely unknown. To address this, we used three closely related gull species as a model system and collected more than 3000 faecal samples during breeding times in nine European countries. Samples were screened for ESBL-producing bacteria, which were characterized to the level of ESBL genotype groups (SHV, TEM), or specific genotypes (CTX-M).ResultsESBL-producing bacteria were frequently detected in gulls (906 of 3158 samples, 28.7 %), with significant variation in prevalence rates between countries. Highest levels were found in Spain (74.8 %), The Netherlands (37.8 %) and England (27.1 %). Denmark and Poland represented the other extreme with no, or very few positive samples. Genotyping of CTX-M isolates identified 13 different variants, with blaCTX-M-1 and blaCTX-M-14 as the most frequently detected. In samples from England, Spain and Portugal, blaCTX-M-14 dominated, while in the rest of the sampled countries blaCTX-M-1 (except Sweden where blaCTX-M-15 was dominant) was the most frequently detected genotype, a pattern similar to what is known from studies of human materials.ConclusionsCTX-M type ESBLs are common in the faecal microbiota from gulls across Europe. The gull ESBL genotype distribution was in large similar to published datasets from human and food-production animals in Europe. The data suggests that the environmental dissemination of ESBL is high from anthropogenic sources, and widespread occurrence of resistant bacteria in common migratory bird species utilizing urban and agricultural areas suggests that antibiotic resistance genes may also be spread through birds.

Highlights

Extended spectrum β-lactamases (ESBLs), a group of enzymes conferring resistance to third generation cephalosporins have rapidly increased in Enterobacteriacae and pose a major challenge to human health care
The Netherlands, England and Sweden had high levels of extended spectrum beta-lactamase (ESBL) producing bacteria (37.8, 27.1 %, respectively 20.7 %), while only 0.8 % of the samples in Poland, and in Denmark no ESBL positive samples were detected at all (Table 2)
In our study all countries except Denmark and Poland had ESBL levels higher presented for clinical E. coli isolates from Europe in the corresponding countries, AmpC was included in the Ears-net report and the sample populations are very different

Summary

Introduction

Extended spectrum β-lactamases (ESBLs), a group of enzymes conferring resistance to third generation cephalosporins have rapidly increased in Enterobacteriacae and pose a major challenge to human health care. In food production animals ESBL-producing bacteria mainly occur in poultry, but are reported with lower prevalence rates in cattle and swine, with blaCTX-M-1, blaCTX-M-14, blaTEM-52 and blaSHV-12 as the currently most frequently reported genotypes [5]. A coherence between poultry and human ESBLs has been shown by sequence typed E. coli comparisons [6], illustrating transmission of resistant strains between sources Both the clonality of E. coli and specific resistance genotypes are important study topics for fully understanding how transfer of resistance may occur. This is concluded by Lazarus et al in a systematic review, finding that food production animals, more apparent for poultry, may constitute a source of human extraintestinal ESCR-EC (expanded-spectrum cephalosporin-resistant Escherichia coli) infections. This is concluded by Lazarus et al in a systematic review, finding that food production animals, more apparent for poultry, may constitute a source of human extraintestinal ESCR-EC (expanded-spectrum cephalosporin-resistant Escherichia coli) infections. [7]

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