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Carbapenem-resistant Salmonella has recently aroused increasing attention. In this study, a total of four sequence type 36 Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) isolates were consecutively isolated from an 11-month-old female patient with a gastrointestinal infection, of which one was sensitive to carbapenems and three were resistant to carbapenems. Via antibiotic susceptibility testing, a carbapenemases screening test, plasmid conjugation experiments, Illumina short-reads, and PacBio HiFi sequencing, we found that all four S. Typhimurium isolates contained a blaCTX-M-14-positive IncI1 plasmid. One carbapenem-sensitive S. Typhimurium isolate then obtained an IncHI2 plasmid carrying blaNDM-1 and an IncP plasmid without any resistance genes during the disease progression. The blaNDM-1 gene was located on a new 30 kb multiple drug resistance region, which is flanked by IS26 and TnAs2, respectively. In addition, the ST_F0903R isolate contained eight tandem copies of the ISCR1 unit (ISCR1-dsbD-trpF-ble-blaNDM-1-ISAba125Δ1), but an increase in MICs to carbapenems was not observed. Our work further provided evidence of the rapid spread and amplification of blaNDM-1 through plasmid. Prompting the recognition of carbapenem-resistant Enterobacterales and the initiation of appropriate infection control measures are essential to avoid the spread of these organisms. [ABSTRACT FROM AUTHOR]

Abstract Yellow pigment content, mainly due to the accumulation of carotenoids, is a quality trait in durum wheat grain as it confers the bright yellow color to pasta preferred by consumers. Also, carotenoids are essential nutrients exerting important biological functions in human health. Consequently, biofortification strategies have been developed in many crops to increase carotenoid content. In this context, carotenoid esterification is emerging as a new breeding target for wheat biofortification, as carotenoid esters have been found to promote both carotenoid accumulation and stability. Until recently, no carotenoid esters have been identified in significant proportions in durum wheat grains, and interspecific breeding programs have been started to transfer esterification ability from common wheat and Hordeum chilense. In this work, XAT-7A1 is identified as the gene responsible for carotenoid esterification in durum wheat. Sequencing, copy number variation and mapping results show that XAT-7A1 is organized as tandem or proximal GDSL esterase/lipase copies in chromosome 7A. Three XAT-7A1 haplotypes are described: Type 1 copies, associated with high levels of carotenoid esters (diesters and monoesters) production and high expression in grain development; Type 2 copies, present in landraces with low levels of carotenoid esters (monoesters) or no esters; and Type 3 copies, without the signal peptide, resulting in zero-ester phenotypes. The identification of XAT-7A1 is a necessary step to make the carotenoid esterification ability available for durum and bread wheat breeding, which should be focused on the Type 1 XAT-7A1 haplotype, which may be assessed as a single gene since XAT-7A1 copies are inherited together.

Yellow pigment content, mainly due to the accumulation of carotenoids, is a quality trait in durum wheat grain as it confers the bright yellow color to pasta preferred by consumers. Also, carotenoids are essential nutrients exerting important biological functions in human health. Consequently, biofortification strategies have been developed in many crops to increase carotenoid content. In this context, carotenoid esterification is emerging as a new breeding target for wheat biofortification, as carotenoid esters have been found to promote both carotenoid accumulation and stability. Until recently, no carotenoid esters have been identified in significant proportions in durum wheat grains, and interspecific breeding programs have been started to transfer esterification ability from common wheat and Hordeum chilense. In this work, XAT-7A1 is identified as the gene responsible for carotenoid esterification in durum wheat. Sequencing, copy number variation and mapping results show that XAT-7A1 is organized as tandem or proximal GDSL esterase/lipase copies in chromosome 7A. Three XAT-7A1 haplotypes are described: Type 1 copies, associated with high levels of carotenoid esters (diesters and monoesters) production and high expression in grain development; Type 2 copies, present in landraces with low levels of carotenoid esters (monoesters) or no esters; and Type 3 copies, without the signal peptide, resulting in zero-ester phenotypes. The identification of XAT-7A1 is a necessary step to make the carotenoid esterification ability available for durum and bread wheat breeding, which should be focused on the Type 1 XAT-7A1 haplotype, which may be assessed as a single gene since XAT-7A1 copies are inherited together. [ABSTRACT FROM AUTHOR]

Carbapenem-resistant Salmonella has recently aroused increasing attention. In this study, a total of four sequence type 36 Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) isolates were consecutively isolated from an 11-month-old female patient with a gastrointestinal infection, of which one was sensitive to carbapenems and three were resistant to carbapenems. Via antibiotic susceptibility testing, a carbapenemases screening test, plasmid conjugation experiments, Illumina short-reads, and PacBio HiFi sequencing, we found that all four S. Typhimurium isolates contained a blaCTX-M-14-positive IncI1 plasmid. One carbapenem-sensitive S. Typhimurium isolate then obtained an IncHI2 plasmid carrying blaNDM-1 and an IncP plasmid without any resistance genes during the disease progression. The blaNDM-1 gene was located on a new 30 kb multiple drug resistance region, which is flanked by IS26 and TnAs2, respectively. In addition, the ST_F0903R isolate contained eight tandem copies of the ISCR1 unit (ISCR1-dsbD-trpF-ble-blaNDM-1-ISAba125Δ1), but an increase in MICs to carbapenems was not observed. Our work further provided evidence of the rapid spread and amplification of blaNDM-1 through plasmid. Prompting the recognition of carbapenem-resistant Enterobacterales and the initiation of appropriate infection control measures are essential to avoid the spread of these organisms.

Carbapenem-resistant Salmonella has recently aroused increasing attention. In this study, a total of four sequence type 36 Salmonella enterica subsp. enterica serovar Typhimurium ( S. Typhimurium) isolates were consecutively isolated from an 11-month-old female patient with a gastrointestinal infection, of which one was sensitive to carbapenems and three were resistant to carbapenems. Via antibiotic susceptibility testing, a carbapenemases screening test, plasmid conjugation experiments, Illumina short-reads, and PacBio HiFi sequencing, we found that all four S. Typhimurium isolates contained a bla CTX-M-14 -positive IncI1 plasmid. One carbapenem-sensitive S. Typhimurium isolate then obtained an IncHI2 plasmid carrying bla NDM-1 and TnAs2, respectively. In addition, the ST_F0903R isolate contained eight tandem copies of the IS bla NDM-1 gene was located on a new 30 kb multiple drug resistance region, which is flanked by IS 26 and TnAs2, respectively. In addition, the ST_F0903R isolate contained eight tandem copies of the IS CR1 unit (IS CR1 - dsbD - trpF - ble - bla NDM-1 -IS Aba125 Δ1), but an increase in MICs to carbapenems was not observed. Our work further provided evidence of the rapid spread and amplification of bla NDM-1 through plasmid. Prompting the recognition of carbapenem-resistant Enterobacterales and the initiation of appropriate infection control measures are essential to avoid the spread of these organisms.

The rapid spread of the bla gene is a major public health concern. Here, we describe the multidrug-resistant Proteus mirabilis strain XH1653, which contains a novel SXT/R391 integrative and conjugative element (ICE), harboring two tandem copies of NDM-1 gene is a major public health concern. Here, we describe the multidrug-resistant Proteus mirabilis strain XH1653, which contains a novel SXT/R391 integrative and conjugative element (ICE), harboring two tandem copies of bla NDM-1 and 21 other resistance genes. XH1653 was resistant to all antibiotics tested, apart from aztreonam. Whole-genome data revealed that two copies of bla NDM-1 embedded in the IS CR1 element are located in HS4 of the novel ICE, which we named ICE Pmi ChnXH1653. A circular intermediate of ICE Pmi evolution experiments under nonselective conditions showed that the two tandem copies of the IS -7 . In the recipient strain, the ICE exhibited a higher excision frequency and extrachromosomal copy number than the ICE in the donor strain. We also observed that the presence of ICE Pmi element can be lost during repeated laboratory passage. This is the first report of a novel SXT/R391 ICE carrying two tandem copies of In vitro evolution experiments under nonselective conditions showed that the two tandem copies of the IS CR1 element and the IS Vsa3 ChnXH1653, which contains two tandem copies of the carbapenemase gene bla NDM-1 , which also illustrates the role that ICEs may play as platforms for the accumulation and transmission of antibiotic resistance genes. IMPORTANCE The occurrence of carbapenemase-producing Proteus mirabilis, especially those strains producing NDM-1 and its variants, is a major public health concern worldwide. The integrative conjugative element (ICE) plays an important role in horizontal acquisition of resistance genes. In this study, we characterized a novel SXT/R391 ICE from a clinical P. mirabilis isolate that we named ICE Pmi ChnXH1653, which contains two tandem copies of the carbapenemase gene bla NDM-1 . We performed an integrative approach to gain insights into different aspects of ICE Pmi ChnXH1653 evolution and biology and observed that ICE Pmi ChnXH1653 obtained the carbapenemase gene bla NDM-1 by IS CR1 -mediated homologous recombination. Our study reveals that the transmission of bla NDM-1 by IS CR1 elements or ICEs may be an important contributor to the carbapenem resistance development across species, which could improve our understanding of horizontal gene transfer in clinical environments.