Complete Sequencing of the blaNDM-1-Positive IncA/C Plasmid from Escherichia coli ST38 Isolate Suggests a Possible Origin from Plant Pathogens

Abstract

The complete sequence of the plasmid pNDM-1_Dok01 carrying New Delhi metallo-β-lactamase (NDM-1) was determined by whole genome shotgun sequencing using Escherichia coli strain NDM-1_Dok01 (multilocus sequence typing type: ST38) and the transconjugant E. coli DH10B. The plasmid is an IncA/C incompatibility type composed of 225 predicted coding sequences in 195.5 kb and partially shares a sequence with bla CMY-2-positive IncA/C plasmids such as E. coli AR060302 pAR060302 (166.5 kb) and Salmonella enterica serovar Newport pSN254 (176.4 kb). The bla NDM-1 gene in pNDM-1_Dok01 is terminally flanked by two IS903 elements that are distinct from those of the other characterized NDM-1 plasmids, suggesting that the bla NDM-1 gene has been broadly transposed, together with various mobile elements, as a cassette gene. The chaperonin groES and groEL genes were identified in the bla NDM-1-related composite transposon, and phylogenetic analysis and guanine-cytosine content (GC) percentage showed similarities to the homologs of plant pathogens such as Pseudoxanthomonas and Xanthomonas spp., implying that plant pathogens are the potential source of the bla NDM-1 gene. The complete sequence of pNDM-1_Dok01 suggests that the bla NDM-1 gene was acquired by a novel composite transposon on an extensively disseminated IncA/C plasmid and transferred to the E. coli ST38 isolate.

Rhizosphere Microbial Community Composition Affects Cadmium and Zinc Uptake by the Metal-Hyperaccumulating Plant Arabidopsis halleri

“…We found species of known plant pathogens, such as Pseudomonas syringae (58) and Pseudoxanthomonas spp. (59,60), in the rhizosphere of A. halleri grown on gamma-irradiated soil that showed a considerable lower relative sequence abundance in the untreated microcosms. However, further studies are necessary to identify the physiological response mechanisms induced by A. halleri grown on gamma-irradiated soil and to verify if pathogen control mechanisms provide a possible explanation for the lower Cd concentrations in A. halleri's green biomass after growth on gammairradiated soil.…”

In Vivo Transmission of an IncA/C Plasmid in Escherichia coli Depends on Tetracycline Concentration, and Acquisition of the Plasmid Results in a Variable Cost of Fitness

“…It appears that conjugal transfer may play less of a role in IncA/C plasmid dissemination between bacterial species compared to clonal expansion and dissemination within bacterial populations. Although the existing literature supports the notion that IncA/C plasmids have a broad host range (14,(39)(40)(41), it is likely that there are bottlenecks in the dissemination of this plasmid type dependent on conjugal compatibility between bacterial species. This differs from other plasmid types, such as IncP plasmids (23,31), and it has important implications regarding the basic biology of these plasmids and their dissemination.…”

Evaluation of a Double-Disk Synergy Test with a Common Metallo-^|^beta;-Lactamase Inhibitor, Mercaptoacetate, for Detecting NDM-1-Producing Enterobacteriaceae and Acinetobacter baumannii

“…The low sensitivity of the CAZ disk could be ascribed to the coproduction of other b-lactamases such as extended-spectrum blactamases and plasmid-mediated or chromosomally encoded AmpC b-lactamases, which inactivate CAZ without being inhibited by SMA. In fact, it has been reported that NDM-1-producers often simaultaneously carry other b-lactamase genes, such as bla CTX-M , bla CMY , or bla DHA (12,13). Nevertheless, 1 E. cloacae isolate (V-87) produced a clearly enlarged inhibitory zone between the SMA and CAZ disks but not between SMA and MPM or IPM, suggesting the importance of CAZ.…”