Antibiotic resistance patterns in Escherichia coli from gulls in nine European countries

Abstract

BackgroundThe prevalence of antibiotic resistant faecal indicator bacteria from humans and food production animals has increased over the last decades. In Europe, resistance levels in Escherichia coli from these sources show a south-to-north gradient, with more widespread resistance in the Mediterranean region compared to northern Europe. Recent studies show that resistance levels can be high also in wildlife, but it is unknown to what extent resistance levels in nature conform to the patterns observed in human-associated bacteria.MethodsTo test this, we collected 3,158 faecal samples from breeding gulls (Larus sp.) from nine European countries and tested 2,210 randomly isolated E. coli for resistance against 10 antibiotics commonly used in human and veterinary medicine.ResultsOverall, 31.5% of the gull E. coli isolates were resistant to ≥1 antibiotic, but with considerable variation between countries: highest levels of isolates resistant to ≥1 antibiotic were observed in Spain (61.2%) and lowest levels in Denmark (8.3%). For each tested antibiotic, the Iberian countries were either the countries with the highest levels or in the upper range in between-country comparisons, while northern countries generally had a lower proportion of resistant E. coli isolates, thereby resembling the gradient of resistance seen in human and food animal sources.ConclusionWe propose that gulls may serve as a sentinel of environmental levels of antibiotic resistant E. coli to complement studies of human-associated microbiota.

Microdilution testing reveals considerable and diverse antimicrobial resistance of Escherichia coli, thermophilic Campylobacter spp. and Salmonella spp. isolated from wild birds present in urban areas

“…A recent extensive study investigated E. coli isolates from gulls from nine European countries and has shown a north-to-south gradient in resistances (Stedt et al 2014). However, that study did not include samples from central-eastern European countries or other bird species than gulls.…”

‘Disperse abroad in the land’: the role of wildlife in the dissemination of antimicrobial resistance

“…In communal corvid roosts in Europe and the USA, 2.5-6.0% of faecal samples contained resistance genes for vancomycin, an antimicrobial 'of last resort' in human medicine [23,35]. Gulls carrying medically significant AMR are capable of long-range movements and are increasingly found feeding on anthropogenic waste and nesting in urban areas [24,27,36]. Similarly, in aquatic ecosystems, uneaten food and faeces from human sewage, agriculture and aquaculture containing antimicrobials and AMR bacteria can be ingested by wild fish and other organisms, which can travel enormous distances and in some cases enter the human food chain [20].…”

CRECIMIENTO DE L. plantarum y EFECTO SOBRE E. coli, S. typhimurium,C. perfringens, y S. aureus

“…El ajuste del inóculo se realizó mediante la metodología propuesta por Crueger y Crueger [8], para ello se tomó 90 ml de caldo MRS estéril y se adicionó 10 ml de L. plantarum de acuerdo con la regla; luego de incubado se tomó 1 ml y se realizó lectura directa en espectrofotómetro a 625 nm. En los casos donde la población fue superior a la establecida se adicionó caldo estéril [9,10].…”

“…la biomasa se determinó por los métodos de Crueger y Crueger [8] y Rodríguez et al [22], para ello se estableció la velocidad máxima de crecimiento mediante la ecuación 2: (Ec. 2) y el tiempo de duplicación celular (td), se determinó teniendo en cuenta la ecuación 3: (Ec.…”