The Role of Flies in Disseminating Plasmids with Antimicrobial-Resistance Genes Between Farms

Abstract

Dissemination of antimicrobial resistance is a major global public health concern. To clarify the role of flies in disseminating antimicrobial resistance between farms, we isolated and characterized tetracycline-resistant Escherichia coli strains isolated from flies and feces of livestock from four locations housing swine (abattoir, three farms) and three cattle farms. The percentages of isolates from flies resistant to tetracycline, dihydrostreptomycin, ampicillin, and chloramphenicol (80.8%, 61.5%, 53.8%, and 50.0%, respectively) and those from animal feces (80.5%, 78.0%, 41.5%, and 46.3%, respectively) in locations housing swine were significantly higher than those from cattle farms (p<0.05). The rates of resistance in E. coli derived from flies reflected those derived from livestock feces at the same locations, suggesting that antimicrobial resistance spreads between livestock and flies on the farms. The results of pulsed-field gel electrophoresis (PFGE) analysis showed that, with a few exceptions, all E. coli isolates differed. Two pairs of tetracycline-resistant strains harbored similar plasmids with the same tetracycline-resistance genes, although the origin (fly or feces), site of isolation, and PFGE patterns of these strains differed. Therefore, flies may disseminate the plasmids between farms. Our results suggest that flies may be involved not only in spreading clones of antimicrobial-resistant bacteria within a farm but also in the widespread dissemination of plasmids with antimicrobial resistance genes between farms.

Carrier flies of multidrug-resistant Escherichia coli as potential dissemination agent in dairy farm environment

“…Previous studies have discussed the role of flies as vectors of antimicrobial resistance bacteria (Blaak et al, 2014;Davari et al, 2010;Literak et al, 2009;Liu et al, 2013;Macovei and Zurek, 2006;Marshall et al, 1990;Rahuma et al, 2005;Rybaříková et al, 2010;Schaumburg et al, 2016;Solà-Ginés et al, 2015;Usui et al, 2015Usui et al, , 2013Von Salviati et al, 2015;Wang, 2013;Wang et al, 2017;Zurek and Ghosh, 2014). In Brazil, Almeida et al (2014) isolated E. coli, Salmonella spp.…”

“…After detecting E. coli clones from flies and calf feces with the same antimicrobial resistance profile, Usui et al (2015Usui et al ( , 2013 suggested that flies can disseminate antimicrobial resistance genes not only within farm but also between farms. Similarly, Solà-Ginés et al (2015) found the same Extended-spectrum β-lactamase (ESBL)-producing E. coli clone isolated from flies within two broiler farms and suggested it may have happened because flies can travel long distances.…”

Zinc oxide enriched peat influence Escherichia coli infection related diarrhea, growth rates, serum and tissue zinc levels in Norwegian piglets around weaning: five case herd trials

“…Additionally, a large amount of flies were present at Farm 4. Flies are known to transmit bacteria including E. coli [94, 95]. …”

Review of Antimicrobial Resistance in the Environment and Its Relevance to Environmental Regulators

“…On-farm transmission of AMR has been characterized in the literature for a wide range of animals: pigs (Crombé et al, 2013; Novais et al, 2013), cows (Wichmann et al, 2014), and insects (Zurek and Ghosh, 2014; Usui et al, 2015; Hammer et al, 2016). A recent review of the academic literature that address the issue of antibiotic use in agriculture suggests that only seven studies (five percent) argued that there was no link between antibiotic consumption in animals and resistance in humans, while 100 (72%) found evidence of a link (O’Neill and The Review on Antimicrobial Resistance, 2015).…”