11 research outputs found
A Phylogenomic Approach for the Analysis of Colistin Resistance-Associated Genes in Klebsiella Pneumoniae, its Mutational Diversity and Implications for Phenotypic Resistance
The emergence of carbapenemase-producing Klebsiella pneumoniae strains has triggered the use of old antibiotics such as colistin. This is driving the emergence of colistin resistance in multidrug-resistant strains that underlie life-threatening infections. This study analyses the mutational diversity of 22 genes associated with colistin resistance in 140 K. pneumoniae clinical isolates integrated in a high-resolution phylogenetic scenario. Colistin susceptibility was accessed by broth microdilution. A total of 98 isolates were susceptible and 16 were resistant, 10 of which were carbapenemase producers. Across the 22 genes examined, 171 non-synonymous mutations and 9 mutations associated with promoter regions were found. Eighty-five isolates had a truncation and/or deletion in at least one of the 22 genes. However, only seven mutations, the complete deletion of mgrB or insertion sequence (IS)-mediated disruption, were exclusively observed in resistant isolates. Four of these (mgrBIle13fs, pmrBGly207Asp, phoQHis339Asp and ramAIle28Met) comprised novel mutations that are potentially involved in colistin resistance. One strain bore a ISEcp1-blaCTX-M-15::mgrB disruption, underlying co-resistance to third-generation cephalosporins and colistin. Moreover, the high-resolution phylogenetic context shows that most of the mutational diversity spans multiple phylogenetic clades, and most of the mutations previously associated with colistin resistance are clade-associated and present in susceptible isolates, showing no correlation with colistin resistance. In conclusion, the present study provides relevant data on the genetic background of genes involved with colistin resistance deeply rooted across monophyletic groups and provides a better understanding of the genes and mutations involved in colistin resistance.info:eu-repo/semantics/publishedVersio
Whole-genome sequencing resolves a polyclonal outbreak by extended-spectrum beta-lactam and carbapenem-resistant Klebsiella pneumoniae in a Portuguese tertiary-care hospital.
Klebsiella pneumoniae has emerged as an important nosocomial pathogen, with whole-genome sequencing (WGS) significantly improving our ability to characterize associated outbreaks. Our study sought to perform a genome-wide analysis of multiclonal K. pneumoniae isolates (n=39; 23 patients) producing extended spectrum beta-lactamases and/or carbapenemases sourced between 2011 and 2016 in a Portuguese tertiary-care hospital. All isolates showed resistance to third-generation cephalosporins and six isolates (five patients) were also carbapenem resistant. Genome-wide-based phylogenetic analysis revealed a topology representing ongoing dissemination of three main sequence-type (ST) clades (ST15, ST147 and ST307) and transmission across different wards, compatible with missing links that can take the form of undetected colonized patients. Two carbapenemase-coding genes were detected: blaKPC-3, located on a Tn4401d transposon, and blaGES-5 on a novel class 3 integron. Additionally, four genes coding for ESBLs (blaBEL-1, blaCTX-M-8, blaCTX-M-15 and blaCTX-M-32) were also detected. ESBL horizontal dissemination across five clades is highlighted by the similar genetic environments of blaCTX-M-15 gene upstream of ISEcp1 on a Tn3-like transposon. Overall, this study provides a high-resolution genome-wide perspective on the epidemiology of ESBL and carbapenemase-producing K. pneumoniae in a healthcare setting while contributing for the adoption of appropriate intervention and prevention strategies
High-throughput barcoding method for the genetic surveillance of insecticide resistance and species identification in Anopheles gambiae complex malaria vectors.
Surveillance of malaria vector species and the monitoring of insecticide resistance are essential to inform malaria control strategies and support the reduction of infections and disease. Genetic barcoding of mosquitoes is a useful tool to assist the high-throughput surveillance of insecticide resistance, discriminate between sibling species and to detect the presence of Plasmodium infections. In this study, we combined multiplex PCR, custom designed dual indexing, and Illumina next generation sequencing for high throughput single nucleotide polymorphism (SNP)-profiling of four species from the Anopheles (An.) gambiae complex (An. gambiae sensu stricto, An. coluzzii, An. arabiensis and An. melas). By amplifying and sequencing only 14 genetic fragments (500Â bp each), we were able to simultaneously detect Plasmodium infection; insecticide resistance-conferring SNPs in ace1, gste2, vgsc and rdl genes; the partial sequences of nuclear ribosomal internal transcribed spacers (ITS1 and ITS2) and intergenic spacers (IGS), Short INterspersed Elements (SINE), as well as mitochondrial genes (cox1 and nd4) for species identification and genetic diversity. Using this amplicon sequencing approach with the four selected An. gambiae complex species, we identified a total of 15 non-synonymous mutations in the insecticide target genes, including previously described mutations associated with resistance and two new mutations (F1525L in vgsc and D148E in gste2). Overall, we present a reliable and cost-effective high-throughput panel for surveillance of An. gambiae complex mosquitoes in malaria endemic regions
Test of lepton universality in beauty-quark decays
The standard model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown that a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton–proton collision data collected with the LHCb detector at CERN’s Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the standard model, such as a new fundamental interaction between quarks and leptons
Understanding the genetic diversity, antimicrobial resistance, and virulence of Klebsiella pneumoniae bacteria
Klebsiella pneumoniae (Kp) is among the top etiological agents of hospital acquired infections behind only Escherichia coli and Pseudomonas aeruginosa. Due to Kp’s large accessory genome, it rapidly acquires antimicrobial resistance (AMR) genes in response to changing antibiotics used in clinical practice. Carbapenemase producing Kp are a particular problem as the resulting infections have very limited treatment options. Kp is usually described as a nosocomial pathogen, but there are hypervirulent strains of Kp (hvKp) endemic in East Asia, which cause community acquired pyogenic liver abscess. While usually susceptible to antibiotics, hvKp infections disseminate rapidly and require aggressive treatment. In Kp, both AMR and hypervirulence are usually the consequence of horizontally acquired genes. Horizontal gene transfer is mediated by plasmids and might be inhibited by bacterial restriction-modification systems that have been suggested as a bacterial immune system. Restriction-modification systems generate methylation patterns that I have identified in clinical Kp isolates (n=8) using data from the PacBio third-generation sequencing platform. Long reads from this platform allowed me to create complete genome assemblies of these isolates. I have also examined the evolving genomic patterns, including of AMR genes and plasmids, in a longitudinal collection of Kp isolates (n=509; years 1980 to 2019) sourced from Portugal that underwent short-read sequencing on an Illumina platform. The analysis revealed the active transmission of strains with AMR genes. A subsequent analysis of global Kp (n=725) characterised hypervirulence biomarkers in the core and accessory genomes using genome wide association study and machine learning methods. This analysis revealed not only known salmochelin and aerobactin loci, but also other genes putatively linked to hypervirulent phenotype. Extending this work, I applied manifold learning and density-based clustering methods to all publicly available Kp assemblies (n=13,176) to investigate the relationship between carbapenemase genes, hypervirulence genes and plasmids. This analysis identified multiple likely outbreaks of carbapenem resistant hvKp and provided insights into the global dynamics of plasmids and genes they carry. In summary, my work has reinforced the importance of genomics and applied statistical methods to understand Kp hypervirulence, epidemiology, AMR and transmission
Uncovering the genetic diversity in Aedes aegypti insecticide resistance genes through global comparative genomics
Aedes aegypti is vector of many arboviruses including Zika, dengue, yellow fever, West Nile, and Chikungunya. Its control efforts are hampered by widespread insecticide resistance reported in the Americas and Asia, while data from Africa is more limited. Here we use publicly available 729 Ae. aegypti whole-genome sequencing samples from 15 countries, including nine in Africa, to investigate the genetic diversity in four insecticide resistance linked genes: ace-1, GSTe2, rdl and vgsc. Apart from vgsc, the other genes have been less investigated in Ae. aegypti, and almost no genetic diversity information is available. Among the four genes, we identified 1,829 genetic variants including 474 non-synonymous substitutions, some of which have been previously documented, as well as putative copy number variations in GSTe2 and vgsc. Global insecticide resistance phenotypic data demonstrated variable resistance in geographic areas with resistant genotypes. Overall, our work provides the first global catalogue and geographic distribution of known and new amino-acid mutations and duplications that can be used to guide the identification of resistance drivers in Ae. aegypti and thereby support monitoring efforts and strategies for vector control
Genome-wide genetic variation and molecular surveillance of drug resistance in Plasmodium falciparum isolates from asymptomatic individuals in Ouélessébougou, Mali.
Sequence analysis of Plasmodium falciparum parasites is informative in ensuring sustained success of malaria control programmes. Whole-genome sequencing technologies provide insights into the epidemiology and genome-wide variation of P. falciparum populations and can characterise geographical as well as temporal changes. This is particularly important to monitor the emergence and spread of drug resistant P. falciparum parasites which is threatening malaria control programmes world-wide. Here, we provide a detailed characterisation of genome-wide genetic variation and drug resistance profiles in asymptomatic individuals in South-Western Mali, where malaria transmission is intense and seasonal, and case numbers have recently increased. Samples collected from Ouélessébougou, Mali (2019-2020; n = 87) were sequenced and placed in the context of older Malian (2007-2017; n = 876) and African-wide (n = 711) P. falciparum isolates. Our analysis revealed high multiclonality and low relatedness between isolates, in addition to increased frequencies of molecular markers for sulfadoxine-pyrimethamine and lumefantrine resistance, compared to older Malian isolates. Furthermore, 21 genes under selective pressure were identified, including a transmission-blocking vaccine candidate (pfCelTOS) and an erythrocyte invasion locus (pfdblmsp2). Overall, our work provides the most recent assessment of P. falciparum genetic diversity in Mali, a country with the second highest burden of malaria in West Africa, thereby informing malaria control activities
Identification of two insecticide resistance markers in Ethiopian Anopheles stephensi mosquitoes using a multiplex amplicon sequencing assay
Since its first detection in 2012 in Djibouti, Anopheles stephensi has invaded and established in the Horn of Africa, and more recently Nigeria. The expansion of this vector poses a significant threat to malaria control and elimination efforts. Integrated vector management is the primary strategy used to interrupt disease transmission; however, growing insecticide resistance is threatening to reverse gains in global malaria control. We present a next-generation amplicon-sequencing approach, for high-throughput monitoring of insecticide resistance genes (ace1, GSTe2, vgsc and rdl), species identification and characterization of genetic diversity (its2 and cox1) in An. stephensi. Ninety-five An. stephensi mosquitoes, collected in Ethiopia, were screened, identifying 104 SNPs, including the knock-down mutation L958F (L1014F in Musca domestica), and for the first time in this vector species, the A296S substitution (A301S in Drosophila melanogaster) in the rdl locus. Two other amino acid substitutions (ace1-N177D, GSTe2-V189L) were also identified but have not been previously implicated in insecticide resistance. Genetic diversity in the mitochondrial cox1 gene revealed shared haplotypes between Ethiopian An. stephensi with samples from Pakistan, Sudan, and Djibouti. Overall, we present a reliable, cost-effective strategy using amplicon-sequencing to monitor known insecticide resistance mutations, with the potential to identify new genetic variants, to assist in the high-throughput surveillance of insecticide resistance in An. stephensi populations
Emergence of KPC-3- and OXA-181-producing ST13 and ST17 Klebsiella pneumoniae in Portugal: genomic insights on national and international dissemination.
© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved.Background
Carbapenem-resistant Klebsiella pneumoniae (CRKP) strains are of particular concern, especially strains with mobilizable carbapenemase genes such as blaKPC, blaNDM or blaOXA-48, given that carbapenems are usually the last line drugs in the β-lactam class and, resistance to this sub-class is associated with increased mortality and frequently co-occurs with resistance to other antimicrobial classes.
Objectives
To characterize the genomic diversity and international dissemination of CRKP strains from tertiary care hospitals in Lisbon, Portugal.
Methods
Twenty CRKP isolates obtained from different patients were subjected to WGS for species confirmation, typing, drug resistance gene detection and phylogenetic reconstruction. Two additional genomic datasets were included for comparative purposes: 26 isolates (ST13, ST17 and ST231) from our collection and 64 internationally available genomic assemblies (ST13).
Results
By imposing a 21 SNP cut-off on pairwise comparisons we identified two genomic clusters (GCs): ST13/GC1 (n = 11), all bearing blaKPC-3, and ST17/GC2 (n = 4) harbouring blaOXA-181 and blaCTX-M-15 genes. The inclusion of the additional datasets allowed the expansion of GC1/ST13/KPC-3 to 23 isolates, all exclusively from Portugal, France and the Netherlands. The phylogenetic tree reinforced the importance of the GC1/KPC-3-producing clones along with their rapid emergence and expansion across these countries. The data obtained suggest that the ST13 branch emerged over a decade ago and only more recently did it underpin a stronger pulse of transmission in the studied population.
Conclusions
This study identifies an emerging OXA-181/ST17-producing strain in Portugal and highlights the ongoing international dissemination of a KPC-3/ST13-producing clone from Portugal.This study was supported in part by UID/DTP/04138/2019 from Fundação para a Ciência e Tecnologia (FCT), Portugal and by Associação para o Desenvolvimento do Ensino e Investigação da Microbiologia (ADEIM).
R.E. is supported by the FCT through the PhD Fellowships (Grant Reference: 2021.08701.BD). J.P. (CEECIND/00394/2017) is supported by Fundação para a CiĂŞncia e Tecnologia through EstĂmulo Individual ao Emprego CientĂfico. T.G.C. received funding from the Medical Research Council UK (grant nos. MR/K000551/1, MR/M01360X/1, MR/N010469/1, MR/R020973/1, MR/R025576/1, MR/S01988X/1, MR/S03563X/1, MR/X005895/1) and Biotechnology and Biological Sciences Research Council (BBSRC) UK (BB/R013063/1). S.C. received funding from the Bloomsbury Set, Medical Research Council UK (grants MR/R020973/1, MR/R025576/1, MR/S01988X/1, MR/S03563X/1, MR/X005895/1) and the BBSRC UK (BB/R013063/1).info:eu-repo/semantics/publishedVersio
Genomic diversity and antimicrobial resistance in clinical Klebsiella pneumoniae isolates from tertiary hospitals in Southern Ghana.
OBJECTIVES: Comprehensive data on the genomic epidemiology of hospital-associated Klebsiella pneumoniae in Ghana are scarce. This study investigated the genomic diversity, antimicrobial resistance patterns, and clonal relationships of 103 clinical K. pneumoniae isolates from five tertiary hospitals in Southern Ghana-predominantly from paediatric patients aged under 5 years (67/103; 65%), with the majority collected from urine (32/103; 31%) and blood (25/103; 24%) cultures. METHODS: We generated hybrid Nanopore-Illumina assemblies and employed Pathogenwatch for genotyping via Kaptive [capsular (K) locus and lipopolysaccharide (O) antigens] and Kleborate (antimicrobial resistance and hypervirulence) and determined clonal relationships using core-genome MLST (cgMLST). RESULTS: Of 44 distinct STs detected, ST133 was the most common, comprising 23% of isolates (n = 23/103). KL116 (28/103; 27%) and O1 (66/103; 64%) were the most prevalent K-locus and O-antigen types. Single-linkage clustering highlighted the global spread of MDR clones such as ST15, ST307, ST17, ST11, ST101 and ST48, with minimal allele differences (1-5) from publicly available genomes worldwide. Conversely, 17 isolates constituted novel clonal groups and lacked close relatives among publicly available genomes, displaying unique genetic diversity within our study population. A significant proportion of isolates (88/103; 85%) carried resistance genes for ≥3 antibiotic classes, with the blaCTX-M-15 gene present in 78% (n = 80/103). Carbapenem resistance, predominantly due to blaOXA-181 and blaNDM-1 genes, was found in 10% (n = 10/103) of the isolates. CONCLUSIONS: Our findings reveal a complex genomic landscape of K. pneumoniae in Southern Ghana, underscoring the critical need for ongoing genomic surveillance to manage the substantial burden of antimicrobial resistance