Prevalence and Characteristic of Swine-Origin mcr-1-Positive Escherichia coli in Northeastern China
Prevalence and Characteristic of Swine-Origin mcr-1-Positive Escherichia coli in Northeastern China
Blog Article
The emergence of the plasmid-mediated colistin resistance gene mcr-1 is threatening the last-line role of colistin in human medicine.With mcr-1-positive Escherichia coli (E.coli) isolated from food animal being frequently reported in China, the prevalence of mcr-1 in food animal has attracted public attention.
In the present study, a total Eyeshadow Brushes of 105 colistin-resistant E.coli strains were isolated from 200 fecal samples collected from six swine farms in northeastern China.mcr-PCR revealed that the prevalence of mcr-1 in colistin-resistant E.
coli was 53.33% (56/105).mcr-1-positive E.
coli showed extensive antimicrobial resistance profiles with the presence of additional resistance genes, increased expression of multidrug efflux pump-associated genes, and increased biofilm formation ability.MLST differentiated all the mcr-1-positive E.coli into 25 sequence types (STs) and five unknown ST, and the most common ST was ST10 (n = 11).
By phylogenetic group classification, the distribution of all mcr-1-positive E.coli belonging to groups A, B1, B2, and D was 46.43, 35.
71, 5.36, and 5.36%, respectively.
Conjugation experiment demonstrated that most of the mcr-1 were transferable at frequencies of 2.68 × 10–6–3.73 × 10–3 among 30 representative mcr-1-positive E.
coli.The plasmid replicon types IncI2 (n = 9), IncX4 (n = 5), IncHI2 (n = 3), IncN (n = 3), and IncP (n = 1) were detected in the transconjugants.The results of growth assay, competition experiment, and plasmid stability testing showed that acquisition of mcr-1-harboring plasmids could reduce the fitness of bacterial hosts, but mcr-1 remained stable in the recipient strain.
Due to the potential possibility of these mcr-1-positive E.coli being transmitted ZESTY ORANGE to humans through the food chain or through horizontal transmission, therefore, it is necessary to continuously monitor the prevalence and dissemination of mcr-1 in food animal, particularly in swine.