scholarly journals Rapid high-resolution melting genotyping scheme for Escherichia coli based on MLST derived single nucleotide polymorphisms

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matej Bezdicek ◽  
Marketa Nykrynova ◽  
Karel Sedlar ◽  
Stanislava Kralova ◽  
Jana Hanslikova ◽  
...  

AbstractRoutinely used typing methods including MLST, rep-PCR and whole genome sequencing (WGS) are time-consuming, costly, and often low throughput. Here, we describe a novel mini-MLST scheme for Eschericha coli as an alternative method for rapid genotyping. Using the proposed mini-MLST scheme, 10,946 existing STs were converted into 1,038 Melting Types (MelTs). To validate the new mini-MLST scheme, in silico analysis was performed on 73,704 strains retrieved from EnteroBase resulting in discriminatory power D = 0.9465 (CI 95% 0.9726–0.9736) for mini-MLST and D = 0.9731 (CI 95% 0.9726–0.9736) for MLST. Moreover, validation on clinical isolates was conducted with a significant concordance between MLST, rep-PCR and WGS. To conclude, the great portability, efficient processing, cost-effectiveness, and high throughput of mini-MLST represents immense benefits, even when accompanied with a slightly lower discriminatory power than other typing methods. This study proved mini-MLST is an ideal method to screen and subgroup large sets of isolates and/or quick strain typing during outbreaks. In addition, our results clearly showed its suitability for prospective surveillance monitoring of emergent and high-risk E. coli clones’.

2007 ◽  
Vol 56 (10) ◽  
pp. 1363-1369 ◽  
Author(s):  
Sara Y. Tartof ◽  
Owen D. Solberg ◽  
Lee W. Riley

The application of genotyping techniques for subtyping uropathogenic Escherichia coli has contributed to better understanding of the epidemiology of community-acquired urinary tract infection (UTI). However, the current techniques are hampered by limited reproducibility, poor discriminatory power, labour-intensive performance or high cost. A screening test that is sequence-based would provide an inexpensive, reproducible way to subtype E. coli isolates. Such a test, if also discriminatory, would be highly useful for epidemiological studies. The discriminatory ability of 12 putative virulence genes (fimH, fliD, fliM, iha, motA, papA/H, kpsMTII, fepE, fimA, flgA, malG, purD) was evaluated based on single nucleotide polymorphisms (SNPs) in nine uropathogenic E. coli isolates, all previously found to belong to a single multilocus sequence type (MLST) complex (ST69). An additional 25 epidemiologically well-characterized E. coli isolates belonging to 12 distinct MLST clonal complexes were analysed for fimH SNP. None of the 12 genes except fimH were able to further discriminate the nine ST69-complex strains. Isolates belonging to the 12 non-ST69 MLST groups were separated into 10 fimH SNP subgroups. While fimH SNP analysis may not be an appropriate phylogenetic method, it offers discriminatory power similar to that of MLST and could be used as a simple, inexpensive screening test for epidemiological studies of uropathogenic E. coli.


BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Aner Mesic ◽  
Marija Rogar ◽  
Petra Hudler ◽  
Nurija Bilalovic ◽  
Izet Eminovic ◽  
...  

Abstract Background Single nucleotide polymorphisms (SNPs) in genes encoding mitotic kinases could influence development and progression of gastric cancer (GC). Methods Case-control study of nine SNPs in mitotic genes was conducted using qPCR. The study included 116 GC patients and 203 controls. In silico analysis was performed to evaluate the effects of polymorphisms on transcription factors binding sites. Results The AURKA rs1047972 genotypes (CT vs. CC: OR, 1.96; 95% CI, 1.05–3.65; p = 0.033; CC + TT vs. CT: OR, 1.94; 95% CI, 1.04–3.60; p = 0.036) and rs911160 (CC vs. GG: OR, 5.56; 95% CI, 1.24–24.81; p = 0.025; GG + CG vs. CC: OR, 5.26; 95% CI, 1.19–23.22; p = 0.028), were associated with increased GC risk, whereas certain rs8173 genotypes (CG vs. CC: OR, 0.60; 95% CI, 0.36–0.99; p = 0.049; GG vs. CC: OR, 0.38; 95% CI, 0.18–0.79; p = 0.010; CC + CG vs. GG: OR, 0.49; 95% CI, 0.25–0.98; p = 0.043) were protective. Association with increased GC risk was demonstrated for AURKB rs2241909 (GG + AG vs. AA: OR, 1.61; 95% CI, 1.01–2.56; p = 0.041) and rs2289590 (AC vs. AA: OR, 2.41; 95% CI, 1.47–3.98; p = 0.001; CC vs. AA: OR, 6.77; 95% CI, 2.24–20.47; p = 0.001; AA+AC vs. CC: OR, 4.23; 95% CI, 1.44–12.40; p = 0.009). Furthermore, AURKC rs11084490 (GG + CG vs. CC: OR, 1.71; 95% CI, 1.04–2.81; p = 0.033) was associated with increased GC risk. A combined analysis of five SNPs, associated with an increased GC risk, detected polymorphism profiles where all the combinations contribute to the higher GC risk, with an OR increased 1.51-fold for the rs1047972(CT)/rs11084490(CG + GG) to 2.29-fold for the rs1047972(CT)/rs911160(CC) combinations. In silico analysis for rs911160 and rs2289590 demonstrated that different transcription factors preferentially bind to polymorphic sites, indicating that AURKA and AURKB could be regulated differently depending on the presence of particular allele. Conclusions Our results revealed that AURKA (rs1047972 and rs911160), AURKB (rs2241909 and rs2289590) and AURKC (rs11084490) are associated with a higher risk of GC susceptibility. Our findings also showed that the combined effect of these SNPs may influence GC risk, thus indicating the significance of assessing multiple polymorphisms, jointly. The study was conducted on a less numerous but ethnically homogeneous Bosnian population, therefore further investigations in larger and multiethnic groups and the assessment of functional impact of the results are needed to strengthen the findings.


2007 ◽  
Vol 90 (3) ◽  
pp. 802-809 ◽  
Author(s):  
Ingunn Berget ◽  
Even Heir ◽  
Jelena Petcovic ◽  
Knut Rudi

Abstract Despite great conceptual promise, the use of microarrays in typing approaches has not yet gained wide acceptance. The establishment of proper criteria for determining discriminatory power as well as typability and the accuracy of microarray data remains to be solved. Purely experimental estimations of these parameters would far exceed what is experimentally practical. We therefore used simulations in combination with experimental results in parameter estimations. Our assay was based on 26 single nucleotide polymorphisms (SNPs) identified in the Campylobacter jejuni Multi Locus Sequence Typing (MLST) database (<ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://pubmlst.org/campylobacter/">http://pubmlst.org/campylobacter/</ext-link>). The SNPs were detected using a single nucleotide extension (SNE) typing microarray. Unknown isolates were assigned to the known sequence type(s) by calculating weighted sum of matches minus a weighted sum of mismatches between predicted and candidate genotype. The weights were set according to the Bayesian posterior probability of the SNP classification. These studies showed that any typing or profiling method based on binary data requires an accuracy of <23% error for each datapoint (in our case SNPs) to classify the isolates to the correct allelic profile in 90% of the cases. The classification error for our experimental data was 3.2% (after removing 5 high error SNPs). We therefore conclude that SNE microarrays are promising for future high-throughput typing of bacteria.


2018 ◽  
Author(s):  
Md. Arifuzzaman ◽  
Sarmistha Mitra ◽  
Amir Hamza ◽  
Raju Das ◽  
Nurul Absar ◽  
...  

ABSTRACTBackgroundMutations in SMPX gene can disrupt the normal activity of the SMPX protein which is involved in hearing process.ObjectiveIn this study, deleterious non-synonymous single nucleotide polymorphisms were isolated from the neutral variants by using several bioinformatics tools.MethodFirstly, dbSNP database hosted by NCBI was used to retrieve the SNPs of SMPX gene, secondly, SIFT was used primarily to screen the damaging SNPs. Further, for validation PROVEAN, PredictSNP and PolyPhen 2 were used. I-Mutant 3 was utilized to analyze the protein stability change and MutPred predicted the molecular mechanism of protein stability change. Finally evolutionary conservation was done to study their conservancy by using ConSurf server.ResultsA total of 26 missense (0.6517%) and 3 nonsense variants (0.075%) were retrieved and among them 4 mutations were found deleterious by all the tools of this experiment and are also highly conserved according to ConSurf server. rs772775896, rs759552778, rs200892029 and rs1016314772 are the reference IDs of deleterious mutations where the substitutions are S71L, N19D, A29T and K54N. Loss of Ubiquitination, loss of methylation, loss of glycosylation, and loss of MoRF binding motifs are the root causes of protein stability change.ConclusionThis is the first study regarding nsSNPs of SMPX gene where the most damaging SNPs were screened that are associated with the SMPX gene and can be used for further research to study their effect on protein structure and function, their dynamic behavior and how they actually affect protein’s flexibility.


2002 ◽  
Vol 184 (7) ◽  
pp. 1873-1879 ◽  
Author(s):  
Indira T. Kudva ◽  
Peter S. Evans ◽  
Nicole T. Perna ◽  
Timothy J. Barrett ◽  
Frederick M. Ausubel ◽  
...  

ABSTRACT Escherichia coli O157:H7 (O157) strains demonstrate varied pulsed-field gel electrophoresis patterns following XbaI digestion, which enable epidemiological surveillance of this important human pathogen. The genetic events underlying PFGE differences between strains, however, are not defined. We investigated the mechanisms for strain variation in O157 by recovering and examining nucleotide sequences flanking each of the XbaI restriction enzyme sites in the genome. Our analysis demonstrated that differences between O157 strains were due to discrete insertions or deletions that contained the XbaI sites polymorphic between strains rather than single-nucleotide polymorphisms in the XbaI sites themselves. These insertions and deletions were found to be uniquely localized within the regions of the genome that are specific to O157 compared to E. coli K-12 (O islands), suggesting that strain-to-strain variation occurs in these O islands. These results may be utilized to devise novel strain-typing tools for this pathogen.


BioTechniques ◽  
2021 ◽  
Author(s):  
Magdalena M Bus ◽  
Erik AC de Jong ◽  
Jonathan L King ◽  
Walter van der Vliet ◽  
Joop Theelen ◽  
...  

DNA analyses from challenging samples such as touch evidence, hairs and skeletal remains push the limits of the current forensic DNA typing technologies. Reverse complement PCR (RC-PCR) is a novel, single-step PCR target enrichment method adapted to amplify degraded DNA. The sample preparation process involves a limited number of steps, decreasing the labor required for library preparation and reducing the possibility of contamination due to less sample manipulation. These features of the RC-PCR make the technology a unique application to successfully target single nucleotide polymorphisms (SNPs) in fragmented and low copy number DNA and yield results from samples in which no or limited data are obtained with standard DNA typing methods. The developed RC-PCR short amplicon 85 SNP-plex panel is a substantial improvement over the previously reported 27-plex RC-PCR multiplex that will provide higher discrimination power for challenging DNA sample analyses.


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