scholarly journals Acquisition of Carbapenem Resistance by Plasmid-Encoded-AmpC-Expressing Escherichia coli

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Ria van Boxtel ◽  
Agnes A. Wattel ◽  
Jesús Arenas ◽  
Wil H. F. Goessens ◽  
Jan Tommassen

ABSTRACT Although AmpC β-lactamases can barely degrade carbapenems, if at all, they can sequester them and prevent them from reaching their targets. Thus, carbapenem resistance in Escherichia coli and other Enterobacteriaceae can result from AmpC production and simultaneous reduction of antibiotic influx into the periplasm by mutations in the porin genes. Here we investigated the route and genetic mechanisms of acquisition of carbapenem resistance in a clinical E. coli isolate carrying bla CMY-2 on a plasmid by selecting for mutants that are resistant to increasing concentrations of meropenem. In the first step, the expression of OmpC, the only porin produced in the strain under laboratory conditions, was lost, leading to reduced susceptibility to meropenem. In the second step, the expression of the CMY-2 β-lactamase was upregulated, leading to resistance to meropenem. The loss of OmpC was due to the insertion of an IS1 element into the ompC gene or to frameshift mutations and premature stop codons in this gene. The bla CMY-2 gene was found to be located on an IncIγ plasmid, and overproduction of the CMY-2 enzyme resulted from an increased plasmid copy number due to a nucleotide substitution in the inc gene. The clinical relevance of these genetic mechanisms became evident from the analysis of previously isolated carbapenem-resistant clinical isolates, which appeared to carry similar mutations.

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Brian D. Johnston ◽  
Paul Thuras ◽  
Stephen B. Porter ◽  
Melissa Anacker ◽  
Brittany VonBank ◽  
...  

ABSTRACT Emerging carbapenem resistance in Escherichia coli, including sequence type 131 (ST131), the leading cause of extraintestinal E. coli infections globally, threatens therapeutic efficacy. Accordingly, we determined broth microdilution MICs for three distinctive newer agents, i.e., cefiderocol (CFDC), ceftazidime-avibactam (CZA), and eravacycline (ERV), plus 11 comparators, against 343 carbapenem-resistant (CR) clinical E. coli isolates, then compared susceptibility results with bacterial characteristics and region. The collection comprised 203 U.S. isolates (2002 to 2017) and 141 isolates from 17 countries in Europe, Latin America, and the Asia-West Pacific region (2003 to 2017). Isolates were characterized for phylogenetic group, resistance-associated sequence types (STs) and subsets thereof, and relevant beta-lactamase-encoding genes. CFDC, CZA, and ERV exhibited the highest percent susceptible (82% to 98%) after tigecycline (TGC) (99%); avibactam improved CZA's activity over that of CAZ (11% susceptible). Percent susceptible varied by phylogroup and ST for CFDC and CZA (greatest in phylogroups B2, D, and F, and in ST131, ST405, and ST648). Susceptibility also varied by resistance genotype, being higher with the Klebsiella pneumoniae carbapenemase (KPC) for CZA, lower with metallo-beta-lactamases for CFDC and CZA, and higher with the beta-lactamase CTX-M for ERV. Percent susceptible also varied by global region for CZA (lower in Asia-Pacific) and by U.S. region for ERV (lower in the South and Southeast). Although resistance to comparators often predicted reduced susceptibility to a primary agent (especially CFDC and CZA), even among comparator-resistant isolates the primary-agent-susceptible fraction usually exceeded 50%. These findings clarify the likely utility of CFDC, CZA, and ERV against CR E. coli in relation to multiple bacterial characteristics and geographical region.


2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Brian D. Johnston ◽  
Paul Thuras ◽  
Stephen B. Porter ◽  
Melissa Anacker ◽  
Brittany VonBank ◽  
...  

ABSTRACT Imipenem-relebactam (I-R) is a recently developed carbapenem–beta-lactamase inhibitor combination agent that can overcome carbapenem resistance, which has now emerged in Escherichia coli, including sequence type 131 (ST131) and its fluoroquinolone-resistant H30R subclone, the leading cause of extraintestinal E. coli infections globally. To clarify the likely utility of I-R for carbapenem-resistant (CR) E. coli infections in the United States, we characterized 203 recent CR clinical E. coli isolates from across the United States (years 2002 to 2017) for phylogroup, clonal group (including ST131, H30R, and the CTX-M-15-associated H30Rx subset within H30R), relevant beta-lactamase genes, and broth microdilution MICs for I-R and 11 comparator agents. Overall, I-R was highly active (89% susceptible), more so than all comparators except tigecycline and colistin (both 99% susceptible). I-R’s activity varied significantly in relation to phylogroup, clonal background, resistance genotype, and region. It was greatest among phylogroup B2, ST131-H30R, H30Rx, Klebsiella pneumoniae carbapenemase (KPC)-positive, and northeast U.S. isolates and lowest among phylogroup C, New Delhi metallo-β-lactamase (NDM)-positive, and southeast U.S. isolates. Relebactam improved imipenem’s activity against CR isolates within each phylogroup—especially groups A, B1, and B2—and particularly against isolates containing KPC. I-R remained substantially active against isolates coresistant to comparator agents, albeit somewhat less so than against the corresponding susceptible isolates. These findings suggest that I-R should be useful for treating most CR E. coli infections in the United States, largely independent of coresistance, although this likely will vary in relation to the local prevalence of specific E. coli lineages and carbapenem resistance mechanisms.


2016 ◽  
Vol 60 (11) ◽  
pp. 6795-6805 ◽  
Author(s):  
Amit Ranjan ◽  
Sabiha Shaik ◽  
Agnismita Mondal ◽  
Nishant Nandanwar ◽  
Arif Hussain ◽  
...  

ABSTRACTThe global dissemination and increasing incidence of carbapenem-resistant, Gram-negative organisms have resulted in acute public health concerns. Here, we present a retrospective multicenter study on molecular characterization of metallo-β-lactamase (MBL)-producing clinicalEscherichia coliisolates recovered from extraintestinal infections in two hospitals in Pune, India. We screened a large sample size of 510E. coliisolates for MBL production wherein we profiled their molecular determinants, antimicrobial resistance phenotypes, functional virulence properties, genomic features, and transmission dynamics. Approximately 8% of these isolates were MBL producers, the majority of which were of the NDM-1 (69%) type, followed by NDM-5 (19%), NDM-4 (5.5%), and NDM-7 (5.5%). MBL producers were resistant to all antibiotics tested except for colistin, fosfomycin, and chloramphenicol, which were effective to various extents. Plasmids were found to be an effective means of dissemination of NDM genes and other resistance traits. All MBL producers adhered to and invaded bladder epithelial (T24) cells and demonstrated significant serum resistance. Genomic analysis of MBL-producingE. coliisolates revealed higher resistance but a moderate virulence gene repertoire. A subset of NDM-1-positiveE. coliisolates was identified as dominant sequence type 101 (ST101) while two strains belonging to ST167 and ST405 harbored NDM-5. A majority of MBL-producingE. colistrains revealed unique genotypes, suggesting that they were clonally unrelated. Overall, the coexistence of virulence and carbapenem resistance in clinicalE. coliisolates is of serious concern. Moreover, the emergence of NDM-1 among the globally dominantE. coliST101 isolates warrants stringent surveillance and control measures.


2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Po-Yu Liu ◽  
Yu-Lin Lee ◽  
Min-Chi Lu ◽  
Pei-Lan Shao ◽  
Po-Liang Lu ◽  
...  

ABSTRACT A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored blaKPC (n = 17), blaOXA-48 (n = 2), and blaVIM (n = 1) genes.


2020 ◽  
Vol 64 (6) ◽  
Author(s):  
Ching-Hsun Wang ◽  
L. Kristopher Siu ◽  
Feng-Yee Chang ◽  
Yu-Kuo Tsai ◽  
Yi-Tsung Lin ◽  
...  

ABSTRACT We report the first clinical Escherichia coli strain EC3000 with concomitant chromosomal colistin and carbapenem resistance. A novel in-frame deletion, Δ6-11 (RPISLR), in pmrB that contributes to colistin resistance was verified using recombinant DNA techniques. Although being less fit than the wild-type (WT) strain or EC3000 revertant (chromosomal replacement of WT pmrB in EC3000), a portion of serially passaged EC3000 strains preserving colistin resistance without selective pressure raises the concern for further spread.


2014 ◽  
Vol 58 (4) ◽  
pp. 2472-2474 ◽  
Author(s):  
Laurent Poirel ◽  
Encho Savov ◽  
Arzu Nazli ◽  
Angelina Trifonova ◽  
Iva Todorova ◽  
...  

ABSTRACTTwelve consecutive carbapenem-resistantEscherichia coliisolates were recovered from patients (infection or colonization) hospitalized between March and September 2012 in different units at a hospital in Bulgaria. They all produced the carbapenemase NDM-1 and the extended-spectrum-β-lactamase CTX-M-15, together with the 16S rRNA methylase RmtB, conferring high-level resistance to all aminoglycosides. All those isolates were clonally related and belonged to the same sequence type, ST101. In addition to being the first to identify NDM-producing isolates in Bulgaria, this is the very first study reporting an outbreak of NDM-1-producingE. coliin the world.


2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Bao-Tao Liu ◽  
Feng-Jing Song ◽  
Ming Zou ◽  
Zhi-Hui Hao ◽  
Hu Shan

ABSTRACT We report the presence of mcr-1 in Escherichia coli and carbapenem-resistant Cronobacter sakazakii from the same diseased chicken. The mcr-1 gene linked with ISApl1 was located on two different IncI2 plasmids, including one multidrug plasmid in E. coli, whereas fosA3-bla NDM-9 was on an IncB/O plasmid in C. sakazakii. The development of the fosA3-bla NDM-9 resistance region was mediated by IS26. The colocation of mcr-1 or bla NDM-9 with other resistance genes will accelerate the dissemination of the two genes.


2019 ◽  
Author(s):  
Nicholas M. Thomson ◽  
Mark J. Pallen

AbstractFlagellin is the major constituent of the flagellar filament and faithful restoration of wild-type motility to flagellin mutants may be beneficial for studies of flagellar biology and biotechnological exploitation of the flagellar system. Therefore, we explored the restoration of motility by flagellin expressed from a variety of combinations of promoter, plasmid copy number and induction strength. Motility was only partially restored using the tightly regulated rhamnose promoter, but wild-type motility was achieved with the T5 promoter, which, although leaky, allowed titration of induction strength. Motility was little affected by plasmid copy number when dependent on inducible promoters. However, plasmid copy number was important when expression was controlled by the native E. coli flagellin promoter. Motility was poorly correlated with flagellin transcription levels, but strongly correlated with the amount of flagellin associated with the flagellar filament, suggesting that excess monomers are either not exported or not assembled into filaments. This study provides a useful reference for further studies of flagellar function and a simple blueprint for similar studies with other proteins.


2019 ◽  
Vol 8 (34) ◽  
Author(s):  
Gregory H. Tyson ◽  
Cong Li ◽  
Olgica Ceric ◽  
Renate Reimschuessel ◽  
Stephen Cole ◽  
...  

The carbapenem resistance gene bla NDM-5 was identified in an Escherichia coli strain isolated from a dog. We report here the complete genome sequence of this E. coli strain; the bla NDM-5 gene was present on a large IncFII multidrug-resistant plasmid. This is the first bla NDM-5-carrying E. coli strain from an animal in the United States.


2013 ◽  
Vol 58 (2) ◽  
pp. 1146-1152 ◽  
Author(s):  
Jia Chang Cai ◽  
Rong Zhang ◽  
Yan Yan Hu ◽  
Hong Wei Zhou ◽  
Gong-Xiang Chen

ABSTRACTTwenty-two KPC-2-producingEscherichia coliisolates were obtained from three hospitals in Hangzhou, China, from 2007 to 2011. One isolate, with OmpC porin deficiency, exhibited high-level carbapenem resistance. Pulsed-field gel electrophoresis showed that few isolates were indistinguishable or closely related. Multilocus sequence typing indicated that sequence type 131 (ST131) was the predominant type (9 isolates, 40.9%), followed by ST648 (5 isolates), ST405 (2 isolates), ST38 (2 isolates), and 4 single STs, ST69, ST2003, ST2179, and ST744. Phylogenetic analysis indicated that 9 group B2 isolates belonged to ST131, and 5 of 11 group D isolates belonged to ST648. Only one group B1 isolate and one group A isolate were identified. A representative plasmid (pE1) was partially sequenced, and a 7,788-bp DNA fragment encoding Tn3transposase, Tn3resolvase, ISKpn8transposase, KPC-2, and ISKpn6-like transposase was obtained. TheblaKPC-2-surrounding sequence was amplified by a series of primers. The PCR results showed that 13 isolates were consistent with the genetic environment in pE1. It is the first report of rapid emergence of KPC-2-producingE. coliST131 in China. TheblaKPC-2gene of most isolates was located on a similar genetic structure.


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