Carbapenem-and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years.Here,we report the carbapenem-and colistin-resistant Enterobacter harboring bla_(IMI) isolated from intestinal sam...Carbapenem-and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years.Here,we report the carbapenem-and colistin-resistant Enterobacter harboring bla_(IMI) isolated from intestinal samples and the environment of a duck farm in China.Four bla_(IMI)-positive Enterobacter isolates were resistant to carbapenem and colistin.Three bla_(IMI) subtypes were detected in different molecular categories of Enterobacter.The detection of the various IMI producers highlights the diversity of carbapenemases in a duck farm.Whole-genome sequencing demonstrated the bla_(IMI) genes were present in chromosomes or plasmids in these strains.The conjugation experiment demonstrated the ability of bla_(IMI)-carrying plasmid to transmit horizontally.The molecular evolution characteristics were examined through comparative genetic analysis.The study demonstrated the presence of chromosomal and plasmid bla_(IMI) and the bla_(IMI)-carrying plasmid exhibits a horizontal transmission between Enterobacter and Escherichia coli C600.The similar genetic content was discovered between two bla_(IMI-16)-positive Enterobacter asburiae.In addition,a bla_(IMI-16)-carrying plasmid is an IncFII(Yp)plasmid,and a substantial amount of mobile genetic elements were identified around bla_(IMI-16).The IS-like elements and IncFII(Yp)plasmid are significant in the propagation of bla_(IMI).Our study provides evidence for the transmission of diverse bla_(IMI) genes in China and supplies additional reference data for bla_(IMI)-positive antimicrobialresistant Enterobacter.Routine surveys of bla_(IMI)-positive Enterobacter from animal-raising environments must be given more focus.展开更多
A gas chromatography-mass spectrometry(GC-MS)method to determine eight anabolic steroids(diethylstilbestrol,methyltestosterone,norethindrone,17α-ethynylestradiol,estradiol,6α-methyl-17α-hydroxy-progesterone,estradi...A gas chromatography-mass spectrometry(GC-MS)method to determine eight anabolic steroids(diethylstilbestrol,methyltestosterone,norethindrone,17α-ethynylestradiol,estradiol,6α-methyl-17α-hydroxy-progesterone,estradiol benzoate,and chlormadinone acetate)was developed.Muscle samples were extracted with liquid-liquid extraction and clean-up was performed in two steps,the extracts obtained were derivatized with heptafluorbutyric(HBF)anhydride and analyzed by GC-MS.In the above method,the linear scope was 2.5-50μg kg^-1.The range of the recoveries was 78.5-148%for diethylstilbestrol,70.8-109%for methyltestosterone,69.8-87.2%for norethindrone,67.7-120%for 17α-ethynylestradiol,82.8-103%for estradiol,70.3-99.2%for 6α-methyl-17α-hydroxy-progesterone,73.0-104%for estradiol benzoate,and 72.9-91.8%for chlormadinone acetate.The range of the coefficients of variation within batches was 0.4-12%;the range of the coefficients of variation between batches was 6.4-11%.The limit of detections and the detection capability were 0.99 and 3.30μg kg^-1 for diethylstilbestrol,1.05 and 3.50μg kg^-1 for methyltestosterone,1.19 and 3.97μg kg^-1 for norethindrone,0.94 and 3.13μg kg^-1 for 17α-ethynylestradiol,1.45 and 4.83μg kg^-1 for estradiol,1.56 and 5.20μg kg^-1 for 6α-methyl-17α-hydroxy-progesterone,1.92 and 6.40μg kg^-1 for estradiol benzoate,and 2.41 and 8.03μg kg^-1 for chlormadinone acetate,respectively.These results showed that the method was widely available,accurate,and sensitive.展开更多
基金supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(32121004)。
文摘Carbapenem-and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years.Here,we report the carbapenem-and colistin-resistant Enterobacter harboring bla_(IMI) isolated from intestinal samples and the environment of a duck farm in China.Four bla_(IMI)-positive Enterobacter isolates were resistant to carbapenem and colistin.Three bla_(IMI) subtypes were detected in different molecular categories of Enterobacter.The detection of the various IMI producers highlights the diversity of carbapenemases in a duck farm.Whole-genome sequencing demonstrated the bla_(IMI) genes were present in chromosomes or plasmids in these strains.The conjugation experiment demonstrated the ability of bla_(IMI)-carrying plasmid to transmit horizontally.The molecular evolution characteristics were examined through comparative genetic analysis.The study demonstrated the presence of chromosomal and plasmid bla_(IMI) and the bla_(IMI)-carrying plasmid exhibits a horizontal transmission between Enterobacter and Escherichia coli C600.The similar genetic content was discovered between two bla_(IMI-16)-positive Enterobacter asburiae.In addition,a bla_(IMI-16)-carrying plasmid is an IncFII(Yp)plasmid,and a substantial amount of mobile genetic elements were identified around bla_(IMI-16).The IS-like elements and IncFII(Yp)plasmid are significant in the propagation of bla_(IMI).Our study provides evidence for the transmission of diverse bla_(IMI) genes in China and supplies additional reference data for bla_(IMI)-positive antimicrobialresistant Enterobacter.Routine surveys of bla_(IMI)-positive Enterobacter from animal-raising environments must be given more focus.
基金supposed by the Projects of Agricultural Standards for Veterinary Drug Residues,China
文摘A gas chromatography-mass spectrometry(GC-MS)method to determine eight anabolic steroids(diethylstilbestrol,methyltestosterone,norethindrone,17α-ethynylestradiol,estradiol,6α-methyl-17α-hydroxy-progesterone,estradiol benzoate,and chlormadinone acetate)was developed.Muscle samples were extracted with liquid-liquid extraction and clean-up was performed in two steps,the extracts obtained were derivatized with heptafluorbutyric(HBF)anhydride and analyzed by GC-MS.In the above method,the linear scope was 2.5-50μg kg^-1.The range of the recoveries was 78.5-148%for diethylstilbestrol,70.8-109%for methyltestosterone,69.8-87.2%for norethindrone,67.7-120%for 17α-ethynylestradiol,82.8-103%for estradiol,70.3-99.2%for 6α-methyl-17α-hydroxy-progesterone,73.0-104%for estradiol benzoate,and 72.9-91.8%for chlormadinone acetate.The range of the coefficients of variation within batches was 0.4-12%;the range of the coefficients of variation between batches was 6.4-11%.The limit of detections and the detection capability were 0.99 and 3.30μg kg^-1 for diethylstilbestrol,1.05 and 3.50μg kg^-1 for methyltestosterone,1.19 and 3.97μg kg^-1 for norethindrone,0.94 and 3.13μg kg^-1 for 17α-ethynylestradiol,1.45 and 4.83μg kg^-1 for estradiol,1.56 and 5.20μg kg^-1 for 6α-methyl-17α-hydroxy-progesterone,1.92 and 6.40μg kg^-1 for estradiol benzoate,and 2.41 and 8.03μg kg^-1 for chlormadinone acetate,respectively.These results showed that the method was widely available,accurate,and sensitive.
