Background The discovery of the superbug mcr-1-positive Escherichia coli (MCRPEC) has drew greet attention. Swine-origin multi-drug resistant MCRPEC has been a potential threat to public health and safety. However, there were few detailed studies have been reported on swine MCRPEC in Guangxi, South China. Results In this study, thirty-three MCRPEC strains were detected from 142 E. coli strains from 116 samples in Guangxi in 2018. Which could be classified into eight unique STs and a total of six incompatibility plasmid groups (IncFI, IncHI1, IncY, IncN, IncI1 and IncX1). After that, the susceptibility of MCRPEC isolates to 27 antimicrobial agents belonging to 17 antimicrobial categories was tested. There were nineteen E. coli resistant to 3rd and 4th generation cephalosporins and twelve E. coli resistant to carbapenem resistan. Importantly, the MCRPEC showed high resistance highly resistance for imipenem and meropenem, which were forbidden to use in livestock production. Three MCRPEC strains were further proved to be extensively drug-resistant (XDR), and the other isolates were multi-drug-resistant (MDR). Furthermore, we found that the plasmid-carrying resistance genes coexisted with the mcr-1 gene of the MCRPEC isolates. Which were listed as follows: β-lactamase antimicrobial resistance genes e.g. ESBL genes (blaCTX-M14, blaCTX-M24, blaCTX-M123, blaOXA-1), plasmid-mediated AmpC (pAmpC) gene (blaCMY-2), the carbapenem resistance gene (blaNDM-5), and non-β-lactamase antimicrobial resistance genes (qnrA, qnrB, qnrS, aac (6′)-Ib-cr, tetA, tetB, sul1, sul2, floR, aadA). Conclusion Thirty-three mcr-1-positive E. coli isolates in Guangxi displayed a wide profile of antimicrobial resistance. Plasmid-carrying resistance genes might be the main cause of MCRPEC multidrug resistance. This study highlighted the necessity for long-term surveillance of mcr-1-positive E. coli in pigs.

Background: The discovery of the superbug mcr-1 -positive Escherichia coli (MCRPEC) has attracted worldwide attention. Swine-origin multi-drug resistant MCRPEC is a potential threat to public health and safety. To date, few detailed studies have been reported on swine MCRPEC in Guangxi, South China. Results: In this study, thirty-three MCRPEC strains were identified from 142 E. coli strains isolated from 116 samples in Guangxi in 2018. All MCRPEC isolates were classified into eight unique STs and a total of six incompatibility plasmid groups (IncFI, IncHI1, IncY, IncN, IncI1 and IncX1) were found. Then, susceptibility of MCRPEC isolates to 27 antimicrobial agents belonging to 17 antimicrobial categories was tested. There were nineteen 3rd and 4th generation cephalosporins resistant E. coli and twelve carbapenem resistant E. coli among the 33 MCRPEC strains. Importantly, the MCRPEC were highly resistant to two carbapenem antibiotics, imipenem and meropenem, which were not permitted for use in livestock production. Three MCRPEC strains were further identified to be extensively drug-resistant (XDR), and the other isolates were recognized as multi-drug-resistant (MDR). Moreover, we detected whether the plasmid-carrying resistance genes coexist with the mcr-1 gene of the MCRPEC isolates. At last, β-lactamase antimicrobial resistance genes such as ESBL genes ( bla CTX-M14 , bla CTX-M24 , bla CTX-M123 , bla OXA-1 ), plasmid-mediated AmpC (pAmpC) gene ( bla CMY-2 ), and the carbapenem gene bla NDM-5 were detected. In addition, non-β-lactamase antimicrobial resistance genes such as qnrA , qnrB , qnrS , aac(6’)-Ib-cr , tetA , tetB , sul1 , sul2 , floR , aadA were also detected. Conclusion: Thirty-three mcr-1 -positive E. coli isolates in Guangxi had a wide range of antimicrobial resistance. Plasmid-carrying resistance genes might be the main cause of MCRPEC multidrug resistance. This study highlighted the necessity for long-term surveillance of mcr-1 -positive E. coli in pigs.

Using a single screw extruder for extruding pure UHMWPE, one of the necessary conditions is to generate large enough extrusion pressure [4] . This article launches a comprehensive and detailed study of raw material of the pure UHMWPE resin powder, establishes a mathematical model of extrusion molding pressure of powder in feeding section, and puts forward the N-lamina model of non-plug solid conveying, which is suitable for the powder state material.

Background: The discovery of the superbug mcr-1 -positive Escherichia coli (MCRPEC) has attracted worldwide attention. Swine-origin multi-drug resistant MCRPEC is a potential threat to public health and safety. To date, few detailed studies have been reported on swine MCRPEC in Guangxi, South China. Results: In this study, thirty-three MCRPEC strains were identified from 142 E. coli strains isolated from swine in Guangxi in 2018. All MCRPEC isolates were classified into eight unique STs and a total of six incompatibility plasmid groups (IncFI, IncHI1, IncY, IncN, IncI1 and IncX1) were found. Then, susceptibility of MCRPEC isolates to 27 antimicrobial agents belonging to 17 antimicrobial categories was tested. There were nineteen 3rd and 4th generation cephalosporins resistant E. coli and twelve carbapenem resistant E. coli among the 33 MCRPEC strains. Importantly, the MCRPEC were highly resistant to two carbapenem antibiotics, imipenem and meropenem, which were not permitted for use in livestock production. Three MCRPEC strains were further identified to be extensively drug-resistant (XDR), and the other isolates were recognized as multi-drug-resistant (MDR). Moreover, in order to detect whether the acquired antimicrobial resistance genes coexisted with the mcr-1 gene of the MCRPEC isolates, 22 acquired antimicrobial resistance genes were tested in total plasmid genes of MCRPEC isolates . At last, β-lactamase antimicrobial resistance genes such as ESBL genes ( bla CTX-M14 , bla CTX-M24 , bla CTX-M123 , bla OXA-1 ), plasmid-mediated AmpC (pAmpC) gene ( bla CMY-2 ), and the carbapenem gene bla NDM-5 were detected. In addition, non-β-lactamase antimicrobial resistance genes such as qnrA , qnrB , qnrS , aac(6’)-Ib-cr , tetA , tetB , sul1 , sul2 , floR , aadA were also detected. Conclusion: Thirty-three mcr-1 -positive E. coli isolates in Guangxi had a wide range of antimicrobial resistance. Plasmids carrying resistance genes might be the main cause of MCRPEC multidrug resistance. This study highlights the necessity for long-term surveillance of mcr-1 -positive E. coli in pigs.

Background: The discovery of the superbug mcr-1-positive Escherichia coli (MCRPEC) has drew greet attention. Swine-origin multi-drug resistant MCRPEC has been a potential threat to public health and safety. However, there were few detailed studies have been reported on swine MCRPEC in Guangxi, South China.Results: In this study, thirty-three MCRPEC strains were detected from 142 E. coli strains from 116 samples in Guangxi in 2018. Which could be classified into eight unique STs and a total of six incompatibility plasmid groups (IncFI, IncHI1, IncY, IncN, IncI1 and IncX1). After that, the susceptibility of MCRPEC isolates to 27 antimicrobial agents belonging to 17 antimicrobial categories was tested. There were nineteen E. coli resistant to 3rd and 4th generation cephalosporins and twelve E. coli resistant to carbapenem resistan. Importantly, the MCRPEC showed high resistance highly resistance for imipenem and meropenem, which were forbidden to use in livestock production. Three MCRPEC strains were further proved to be extensively drug-resistant (XDR), and the other isolates were multi-drug-resistant (MDR). Furthermore, we found that the plasmid-carrying resistance genes coexisted with the mcr-1 gene of the MCRPEC isolates. Which were listed as follows: β-lactamase antimicrobial resistance genes e.g. ESBL genes (blaCTX-M14, blaCTX-M24, blaCTX-M123, blaOXA-1), plasmid-mediated AmpC (pAmpC) gene (blaCMY-2), the carbapenem resistance gene (blaNDM-5), and non-β-lactamase antimicrobial resistance genes (qnrA, qnrB, qnrS, aac(6’)-Ib-cr, tetA, tetB, sul1, sul2, floR, aadA).Conclusion: Thirty-three mcr-1-positive E. coli isolates in Guangxi displayed a wide profile of antimicrobial resistance. Plasmid-carrying resistance genes might be the main cause of MCRPEC multidrug resistance. This study highlighted the necessity for long-term surveillance of mcr-1-positive E. coli in pigs.