Modifications in the pmrB gene are the primary mechanism for the development of chromosomally encoded resistance to polymyxins in uropathogenic Escherichia coli

Phan, Minh-Duy; Nhu, Nguyen Thi Khanh; Achard, Maud E. S.; Forde, Brian M.; Hong, Kar‐Wai; Chong, Teik Min; Yin, Wai‐Fong; Chan, Kok‐Gan; West, Nicholas P.; Walker, Mark J.; Paterson, David L.; Beatson, Scott A.; Schembri, Mark A.

doi:10.1093/jac/dkx204

Cited by 46 publications

(54 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have shown previously that the promoter of the chloramphenicol resistance gene in our mini-Tn 5 transposon can drive the transcription of a downstream gene if the insertion position is favorable ( 57 , 74 ). This led to the identification of the rcpA gene as a novel repressor of curli production.…”

Section: Discussionmentioning

confidence: 96%

Discovery of New Genes Involved in Curli Production by a Uropathogenic Escherichia coli Strain from the Highly Virulent O45:K1:H7 Lineage

Nhu

Phan

Peters

et al. 2018

mBio

Self Cite

View full text Add to dashboard Cite

Curli are bacterial surface-associated amyloid fibers that bind to the dye Congo red (CR) and facilitate uropathogenic Escherichia coli (UPEC) biofilm formation and protection against host innate defenses. Here we sequenced the genome of the curli-producing UPEC pyelonephritis strain MS7163 and showed it belongs to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. MS7163 produced curli at human physiological temperature, and this correlated with biofilm growth, resistance of sessile cells to the human cationic peptide cathelicidin, and enhanced colonization of the mouse bladder. We devised a forward genetic screen using CR staining as a proxy for curli production and identified 41 genes that were required for optimal CR binding, of which 19 genes were essential for curli synthesis. Ten of these genes were novel or poorly characterized with respect to curli synthesis and included genes involved in purine de novo biosynthesis, a regulator that controls the Rcs phosphorelay system, and a novel repressor of curli production (referred to as rcpA). The involvement of these genes in curli production was confirmed by the construction of defined mutants and their complementation. The mutants did not express the curli major subunit CsgA and failed to produce curli based on CR binding. Mutation of purF (the first gene in the purine biosynthesis pathway) and rcpA also led to attenuated colonization of the mouse bladder. Overall, this work has provided new insight into the regulation of curli and the role of these amyloid fibers in UPEC biofilm formation and pathogenesis.

show abstract

Section: Discussionmentioning

confidence: 96%

Discovery of New Genes Involved in Curli Production by a Uropathogenic Escherichia coli Strain from the Highly Virulent O45:K1:H7 Lineage

Nhu

Phan

Peters

et al. 2018

mBio

Self Cite

View full text Add to dashboard Cite

show abstract

“…For those isolates that did not show any mutation, a reverse transcription-quantitative PCR (qRT-PCR) assay was performed to quantify the relative expression of the above-mentioned genes (35,36). Additionally, a colistin-resistant mutant E. coli strain (Δ806) was developed under selective colistin pressure, as previously described (37).…”

Section: Methodsmentioning

confidence: 99%

Detection of Colistin-Resistant MCR-1-Positive Escherichia coli by Use of Assays Based on Inhibition by EDTA and Zeta Potential

et al. 2017

View full text Add to dashboard Cite

The emergence and rapid dissemination of colistin-resistant carrying the plasmid-mediated gene have created an urgent need to develop specific screening methods. In this study, we evaluated four assays based on the inhibition of MCR-1 activity by EDTA: (i) a combined-disk test (CDT) comparing the inhibition zones of colistin and colistin (10 μg) plus EDTA (100 mM); (ii) reduction of colistin MIC (CMR) in the presence of EDTA (80 μg/ml); (iii) a modified rapid polymyxin Nordmann/Poirel test (MPNP); and (iv) alteration of zeta potential (R = ZP/ZP). We obtained encouraging results for the detection of MCR-1 in isolates recovered from human, food, and animal samples, using the following assay parameters: ≥3 mm difference in the inhibition zones between colistin disks without and with EDTA; ≥4-fold colistin MIC decrease in the presence of EDTA; R of ≥2.5; and the absence of metabolic activity and proliferation, indicated by unchanged color of phenol red in the presence of colistin-EDTA, in the MPNP test. In this regard, the CDT, CMR, R, and MPNP assays exhibited sensitivities of 96.7, 96.7, 95.1, and 96.7% and specificities of 89.6, 83.3, 100, and 100%, respectively, for detecting MCR-1-positive Our results demonstrate that inhibition by EDTA and zeta potential assays may provide simple and inexpensive methods for the presumptive detection of MCR-1-producing isolates in human and veterinary diagnostic laboratories.

show abstract

“…Additionally, we looked for mutations in pmrA and pmrB genes that modified the length of the protein. 19 Mutations in other genes involved in chromosomal colistin resistance in other bacteria…”

Section: Plasmid Sequencing and Identification Of Plasmid-mediated Comentioning

confidence: 99%

Colistin resistance in Parisian inpatient faecal Escherichia coli as the result of two distinct evolutionary pathways

Bourrel

Poirel

Royer

et al. 2019

Journal of Antimicrobial Chemotherapy

View full text Add to dashboard Cite

Background: Beyond plasmid-encoded resistance (mcr genes) prevalence in strain collections, large epidemiological studies to estimate the human burden of colistin-resistant Escherichia coli gut carriage are lacking. Objectives: To evaluate the prevalence of colistin-resistant E. coli carriage in inpatients and decipher the molecular support of resistance and the genetic background of the strains. Methods: During a 3 month period in 2017, we prospectively screened patients in six Parisian hospitals for rectal carriage of colistin-resistant E. coli using a selective medium, a biochemical confirmatory test and MIC determination. WGS of the resistant strains and their corresponding plasmids was performed. Results: Among the 1217 screened patients, 153 colistin-resistant E. coli strains were isolated from 152 patients (12.5%). The mcr-1 gene was identified in only seven isolates (4.6%) on different plasmid scaffolds. The genetic background of these MCR-1 producers argued for an animal origin. Conversely, the remaining 146 colistinresistant E. coli exhibited a phylogenetic distribution corresponding to human gut commensal/clinical population structure (B2 and D phylogroup predominance); 72.6% of those isolates harboured convergent mutations in the PmrA and PmrB proteins, constituting a two-component system shown to be associated with colistin resistance. Conclusions: We showed that the occurrence at a high rate of colistin resistance in human faecal E. coli is the result of two distinct evolutionary pathways, i.e. the occurrence of chromosomal mutations in an endogenous E. coli population and the rare acquisition of exogenous mcr-1-bearing strains probably of animal origin. The involved selective pressures need to be identified in order to develop preventative strategies.

show abstract

Modifications in the pmrB gene are the primary mechanism for the development of chromosomally encoded resistance to polymyxins in uropathogenic Escherichia coli

Abstract: This study identified the pmrB gene as the main chromosomal target for induction of colistin and polymyxin B resistance in E. coli.

Cited by 46 publications

References 67 publications

Discovery of New Genes Involved in Curli Production by a Uropathogenic Escherichia coli Strain from the Highly Virulent O45:K1:H7 Lineage

Discovery of New Genes Involved in Curli Production by a Uropathogenic Escherichia coli Strain from the Highly Virulent O45:K1:H7 Lineage

Detection of Colistin-Resistant MCR-1-Positive Escherichia coli by Use of Assays Based on Inhibition by EDTA and Zeta Potential

Colistin resistance in Parisian inpatient faecal Escherichia coli as the result of two distinct evolutionary pathways

Contact Info

Product

Resources

About