Migratory wild birds carrying multidrug-resistant Escherichia coli as potential transmitters of antimicrobial resistance in China

Abstract

Migratory birds play an important role in the spread of multidrug-resistant (MDR) bacteria. To investigate the prevalence of MDR Escherichia coli in migratory birds in China and potential relationships with the environment, a total of 1387 samples (fecal samples, cloacal swabs, or throat swabs) were collected from migratory birds from three different river basins in China. The collected samples were processed and subjected to bacteriological examinations. Antimicrobial susceptibility testing of the recovered isolates was performed using the E-test for the detection of minimum inhibitory concentrations (MICs). Some antibiotic resistance genes were detected and the PCR products were confirmed by sequencing. In total, 478 (34.7%) E. coli isolates were recovered. The results showed that the drug-resistant E. coli isolates were highly resistant to β-lactams (43.7%) and tetracycline (22.6%), and 73 (15.3%) were MDR, including eight that were extended spectrum β-lactamase-positive. The retrieved strains harbored the blaCTX-M, blaTEM-1, tet(A), tet(B), tet(M), sul1, sul2, sul3, cmlA, floR, and intI1 genes with a prevalence of 5.9%, 36.4%, 80.5%, 11.9%, 6.8%, 6.8%, 47.5%, 12.7%, 50.8%, 37.3%, and 61.0%, respectively. The drug resistance rate of the isolates from southern China was higher than those from northern China. The E. coli samples collected for migratory birds in the Pearl River Basin had the highest proportion (46.7%) MDR isolates. Furthermore, MDR bacteria carried by migratory birds were closely related to the antibiotic content in the basin, which confirms that MDR bacteria carried by migratory birds are likely acquired from the environment. This study also confirmed that migratory birds are potential transmitters of MDR bacteria, demonstrating the need to reduce the use and emission of antibiotics and further in-depth studies on the mechanisms underlying drug resistance of bacteria.

Migratory birds as the vehicle of transmission of multi drug resistant extended spectrum β lactamase producing Escherichia fergusonii, an emerging zoonotic pathogen

“… Ben Yahia et al (2020) reported the first evidence of ESBL-producing E. coli with the blaCTX-M-15 genes in the wildlife of Tunisia and Africa. Yuan et al (2021) also demonstrated role of migratory birds in disseminating MDR genes. Our study indicates that birds containing pathogenic and antibiotic-resistant genes may disperse them to the new locality and cause infection in other birds, farm animals, and humans.…”

“…E. fergusonii has been a cause of spleen and liver infection in calf and chicken ( Beli and Duraku, 2017 ), non-human primates ( Glover et al, 2017 ) and cattle pneumonia ( Rimoldi and Moeller, 2013 ). Several investigations demonstrate that wild birds uptake the pathogenic bacteria from wastes and shed them into new locality which results in broad-range outbreaks as well as endemic spreads of multidrug-resistant strains ( Sharif et al, 2020 , Yuan et al, 2021 ). The plasmid contains resistant genes that may transfer horizontally to completely different microorganisms and bring structural changes ( Dolejska and Papagiannitsis, 2018 ).…”

Antimicrobial Resistance Development Pathways in Surface Waters and Public Health Implications

“…It is also important to understand that some wild animals with acquired resistance genes can migrate from human-impacted areas to pristine environments and spread the resistance genes. MDR E. coli isolates were detected in migratory birds in both northern and southern China, but the rate of resistance was higher in the south [ 124 ], which confirms the role of the environment in the spread of AR. Animal migration may interfere with our understanding of the origin of AR in pristine environments because the sources of resistant bacteria carried by migratory animals are usually unknown.…”

“…Resistance phenotypes may be transferred from wild birds and mammals to food-producing animals that share the same environment with the wildlife [ 122 ]. Wild animals may spread AR in surface waters through their feces and swimming [ 124 ]. Humans may be infected with zoonotic antimicrobial-resistant pathogens through their interactions with wild animals and their habitats or by killing the animals for food.…”

Occurrence of Antimicrobial-Resistant Escherichia coli in Marine Mammals of the North and Baltic Seas: Sentinels for Human Health

“…Although antibiotics and antimicrobial resistance are known to occur naturally in the environment [ 16 , 20 , 21 ], different anthropogenic sources have been identified as additional sources of environmental contamination [ 22 , 23 , 24 , 25 , 26 ]. Wildlife most probably acquires antimicrobial-resistant bacteria from environmental sources [ 11 , 27 , 28 ], and can also act as a reservoir and vector for infection or colonisation [ 15 , 29 , 30 , 31 ]. In this context, individual wildlife species could be used as effective bioindicators to display the level of environmental contamination as well as the potential of a public health risk caused by antimicrobial-resistant bacteria.…”