Search

Centre for Genomic Pathogen Surveillance and the Euro-GASP study group: Sonja Pleininger, Alexander Indra, Irith De Baetselier, Wim Vanden Berghe, Blaženka Hunjak, Tatjana Nemeth Blažić, Panayiota Maikanti-Charalambous, Despo Pieridou, Hana Zákoucká, Helena Žemličková, Steen Hoffmann, Susan Cowan, Lasse Jessen Schwartz, Rita Peetso, Jevgenia Epstein, Jelena Viktorova, Ndeindo Ndeikoundam, Beatrice Bercot, Cécile Bébéar, Florence Lot, Susanne Buder, Klaus Jansen, Vivi Miriagou, Georgios Rigakos, Vasilios Raftopoulos, Eszter Balla, Mária Dudás, Lena Rós Ásmundsdóttir, Guðrún Sigmundsdóttir, Guðrún Svanborg Hauksdóttir, Thorolfur Gudnason, Aoife Colgan, Brendan Crowley, Sinéad Saab, Paola Stefanelli, Anna Carannante, Patrizia Parodi, Gatis Pakarna, Raina Nikiforova, Antra Bormane, Elina Dimina, Monique Perrin, Tamir Abdelrahman, Joël Mossong, Jean-Claude Schmit, Friedrich Mühlschlegel, Christopher Barbara, Francesca Mifsud, Alje Van Dam, Birgit Van Benthem, Maartje Visser, Ineke Linde, Hilde Kløvstad, Dominique Caugant, Beata Młynarczyk-Bonikowska, Jacinta Azevedo, Maria-José Borrego, Marina Lurdes Ramos Nascimento, Peter Pavlik, Irena Klavs, Andreja Murnik, Samo Jeverica, Tanja Kustec, Julio Vázquez Moreno, Asuncion Diaz, Raquel Abad, Inga Velicko, Magnus Unemo, Helen Fifer, Jill Shepherd, Lynsey Patterson Background: Genomic surveillance using quality-assured whole-genome sequencing (WGS) together with epidemiological and antimicrobial resistance (AMR) data is essential to characterise the circulating Neisseria gonorrhoeae lineages and their association to patient groups (defined by demographic and epidemiological factors). In 2013, the European gonococcal population was characterised genomically for the first time. We describe the European gonococcal population in 2018 and identify emerging or vanishing lineages associated with AMR and epidemiological characteristics of patients, to elucidate recent changes in AMR and gonorrhoea epidemiology in Europe. Methods: We did WGS on 2375 gonococcal isolates from 2018 (mainly Sept 1-Nov 30) in 26 EU and EEA countries. Molecular typing and AMR determinants were extracted from quality-checked genomic data. Association analyses identified links between genomic lineages, AMR, and epidemiological data. Findings: Azithromycin-resistant N gonorrhoeae (8·0% [191/2375] in 2018) is rising in Europe due to the introduction or emergence and subsequent expansion of a novel N gonorrhoeae multi-antigen sequence typing (NG-MAST) genogroup, G12302 (132 [5·6%] of 2375; N gonorrhoeae sequence typing for antimicrobial resistance [NG-STAR] clonal complex [CC]168/63), carrying a mosaic mtrR promoter and mtrD sequence and found in 24 countries in 2018. CC63 was associated with pharyngeal infections in men who have sex with men. Susceptibility to ceftriaxone and cefixime is increasing, as the resistance-associated lineage, NG-MAST G1407 (51 [2·1%] of 2375), is progressively vanishing since 2009-10. Interpretation: Enhanced gonococcal AMR surveillance is imperative worldwide. WGS, linked to epidemiological and AMR data, is essential to elucidate the dynamics in gonorrhoea epidemiology and gonococcal populations as well as to predict AMR. When feasible, WGS should supplement the national and international AMR surveillance programmes to elucidate AMR changes over time. In the EU and EEA, increasing low-level azithromycin resistance could threaten the recommended ceftriaxone-azithromycin dual therapy, and an evidence-based clinical azithromycin resistance breakpoint is needed. Nevertheless, increasing ceftriaxone susceptibility, declining cefixime resistance, and absence of known resistance mutations for new treatments (zoliflodacin, gepotidacin) are promising. This study was supported by the European Centre for Disease Prevention and Control, the Centre for Genomic Pathogen Surveillance, the Li Ka Shing Foundation (Big Data Institute, University of Oxford), the Wellcome Genome Campus, the Foundation for Medical Research at Örebro University Hospital, and grants from Wellcome (098051 and 099202). LSB was funded by Conselleria de Sanitat Universal i Salut Pública, Generalitat Valenciana (Plan GenT CDEI-06/20-B), Valencia, Spain, and Ministry of Science, Innovation and Universities (PID2020–120113RA-I00), Spain, at the time of analysing and writing this manuscript. info:eu-repo/semantics/publishedVersion

Objectives Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global threat and novel treatment alternatives are imperative. Herein, susceptibility to the novel antimicrobial zoliflodacin, currently in a global Phase 3 randomized controlled clinical trial for gonorrhoea treatment, was investigated by screening for zoliflodacin GyrB target mutations in publicly available gonococcal genomes and, where feasible, determination of the associated zoliflodacin MIC. Methods The European Nucleotide Archive was queried using the search term ‘Taxon: 485’. DNA sequences from 27 151 gonococcal isolates were analysed and gyrB, gyrA, parC and parE alleles characterized. Results GyrB amino acid alterations were rare (97.0% of isolates had a wild-type GyrB sequence). GyrB V470L (2.7% of isolates) was the most prevalent alteration, followed by S467N (0.12%), N. meningitidis GyrB (0.092%), V470I (0.059%), Q468R/P (0.015%), A466T (0.0074%), L425I + L465I (0.0037%), L465I (0.0037%), G482S (0.0037%) and D429V (0.0037%). Only one isolate (0.0037%) carried a substitution in a resistance-associated GyrB codon (D429V), resulting in a zoliflodacin MIC of 8 mg/L. None of the other detected gyrB, gyrA, parC or parE mutations caused a zoliflodacin MIC outside the wild-type MIC distribution. Conclusions The zoliflodacin target GyrB was highly conserved among 27 151 global gonococcal isolates cultured in 1928–2021. The single zoliflodacin-resistant clinical isolate (0.0037%) was cultured from a male patient in Japan in 2000. Evidently, this strain has not clonally expanded nor has the gyrB zoliflodacin-resistance mutation disseminated through horizontal gene transfer to other strains. Phenotypic and genomic surveillance, including gyrB mutations, of zoliflodacin susceptibility are imperative.

Summary Background Characterising sexual networks with transmission of sexually transmitted infections might allow identification of individuals at increased risk of infection. We aimed to investigate sexual mixing in Neisseria gonorrhoeae transmission networks between women, heterosexual men, and men who report sex with men (MSM), and between people with and without HIV. Methods In this cross-sectional observational study, we whole-genome sequenced N gonorrhoeae isolates from the archive of the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP).w Isolates that varied by five single nucleotide polymorphisms or fewer were grouped into clusters that represented sexual networks with N gonorrhoeae transmission. Clusters were described by gender, sexual risk group, and HIV status. Findings We sequenced 1277 N gonorrhoeae isolates with linked clinical and sociodemographic data that were collected in five clinics in England during 2013–16 (July 1 to Sept 30 in 2013–15; July 1 to Sept 9 in 2016). The isolates grouped into 213 clusters. 30 (14%) clusters contained isolates from heterosexual men and MSM but no women and three (1%) clusters contained isolates from only women and MSM. 146 (69%) clusters comprised solely people with negative or unknown HIV status and seven (3%) comprised only HIV-positive people. 60 (28%) clusters comprised MSM with positive and negative or unknown HIV status. Interpretation N gonorrhoeae molecular data can provide information indicating risk of HIV or other sexually transmitted infections for some individuals for whom such risk might not be known from clinical history. These findings have implications for sexual health care, including offering testing, prevention advice, and preventive treatment, such as HIV pre-exposure prophylaxis. Funding National Institute for Health Research Health Protection Research Unit; Wellcome; Public Health England.

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global concern. Phylogenetic analyses resolve uncertainties regarding genetic relatedness of isolates with identical phenotypes and inform whether AMR is due to new mutations and clonal expansion or separate introductions by importation. We sequenced 1,277 isolates with associated epidemiologic and antimicrobial susceptibility data collected during 2013–2016 to investigate N. gonorrhoeae genomic variability in England. Comparing genetic markers and phenotypes for AMR, we identified 2 N. gonorrhoeae lineages with different antimicrobial susceptibility profiles and 3 clusters with elevated MICs for ceftriaxone, varying mutations in the penA allele, and different epidemiologic characteristics. Our results indicate N. gonorrhoeae with reduced antimicrobial susceptibility emerged independently and multiple times in different sexual networks in England, through new mutation or recombination events and by importation. Monitoring and control for AMR in N. gonorrhoeae should cover the entire population affected, rather than focusing on specific risk groups or locations.

Background Multidrug-resistant Neisseria gonorrhoeae strains are prevalent, threatening gonorrhoea treatment globally, and understanding of emergence, evolution, and spread of antimicrobial resistance (AMR) in gonococci remains limited. We describe the genomic evolution of gonococci and their AMR, related to the introduction of antimicrobial therapies, examining isolates from 1928 (preantibiotic era) to 2013 in Denmark. This is, to our knowledge, the oldest gonococcal collection globally. Methods Lyophilised isolates were revived and examined using Etest (18 antimicrobials) and whole-genome sequencing (WGS). Quality-assured genome sequences were obtained for 191 viable and 40 non-viable isolates and analysed with multiple phylogenomic approaches. Results Gonococcal AMR, including an accumulation of multiple AMR determinants, started to emerge particularly in the 1950s–1970s. By the twenty-first century, resistance to most antimicrobials was common. Despite that some AMR determinants affect many physiological functions and fitness, AMR determinants were mainly selected by the use/misuse of gonorrhoea therapeutic antimicrobials. Most AMR developed in strains belonging to one multidrug-resistant (MDR) clade with close to three times higher genomic mutation rate. Modern N. gonorrhoeae was inferred to have emerged in the late-1500s and its genome became increasingly conserved over time. Conclusions WGS of gonococci from 1928 to 2013 showed that no AMR determinants, except penB, were in detectable frequency before the introduction of gonorrhoea therapeutic antimicrobials. The modern gonococcus is substantially younger than previously hypothesized and has been evolving into a more clonal species, driven by the use/misuse of antimicrobials. The MDR gonococcal clade should be further investigated for early detection of strains with predispositions to develop and maintain MDR and for initiation of public health interventions.

The incidence of syphilis has risen worldwide in the last decade in spite of being an easily treated infection. The causative agent of this sexually transmitted disease is the bacterium Treponema pallidum subspecies pallidum (TPA), very closely related to subsp. pertenue (TPE) and endemicum (TEN), responsible for the human treponematoses yaws and bejel, respectively. Although much focus has been placed on the question of the spatial and temporary origins of TPA, the processes driving the evolution and epidemiological spread of TPA since its divergence from TPE and TEN are not well understood. Here, we investigate the effects of recombination and selection as forces of genetic diversity and differentiation acting during the evolution of T. pallidum subspecies. Using a custom-tailored procedure, named phylogenetic incongruence method, with 75 complete genome sequences, we found strong evidence for recombination among the T. pallidum subspecies, involving 12 genes and 21 events. In most cases, only one recombination event per gene was detected and all but one event corresponded to intersubspecies transfers, from TPE/TEN to TPA. We found a clear signal of natural selection acting on the recombinant genes, which is more intense in their recombinant regions. The phylogenetic location of the recombination events detected and the functional role of the genes with signals of positive selection suggest that these evolutionary processes had a key role in the evolution and recent expansion of the syphilis bacteria and significant implications for the selection of vaccine candidates and the design of a broadly protective syphilis vaccine.

The sexually transmitted pathogen Neisseria gonorrhoeae is regarded as being on the way to becoming an untreatable superbug. Despite its clinical importance, little is known about its emergence and evolution, and how this corresponds with the introduction of antimicrobials. We present a genome-based phylogeographical analysis of 419 gonococcal isolates from across the globe. Results indicate that modern gonococci originated in Europe or Africa, possibly as late as the sixteenth century and subsequently disseminated globally. We provide evidence that the modern gonococcal population has been shaped by antimicrobial treatment of sexually transmitted infections as well as other infections, leading to the emergence of two major lineages with different evolutionary strategies. The well-described multidrug-resistant lineage is associated with high rates of homologous recombination and infection in high-risk sexual networks. A second, multisusceptible lineage is more associated with heterosexual networks, with potential implications for infection control.

Coscolla et al., Human tuberculosis (TB) is caused by members of the Mycobacterium tuberculosis complex (MTBC). The MTBC comprises several human-adapted lineages known as M. tuberculosis sensu stricto, as well as two lineages (L5 and L6) traditionally referred to as Mycobacterium africanum . Strains of L5 and L6 are largely limited to West Africa for reasons unknown, and little is known of their genomic diversity, phylogeography and evolution. Here, we analysed the genomes of 350 L5 and 320 L6 strains, isolated from patients from 21 African countries, plus 5 related genomes that had not been classified into any of the known MTBC lineages. Our population genomic and phylogeographical analyses showed that the unclassified genomes belonged to a new group that we propose to name MTBC lineage 9 (L9). While the most likely ancestral distribution of L9 was predicted to be East Africa, the most likely ancestral distribution for both L5 and L6 was the Eastern part of West Africa. Moreover, we found important differences between L5 and L6 strains with respect to their phylogeographical substructure and genetic diversity. Finally, we could not confirm the previous association of drug-resistance markers with lineage and sublineages. Instead, our results indicate that the association of drug resistance with lineage is most likely driven by sample bias or geography. In conclusion, our study sheds new light onto the genomic diversity and evolutionary history of M. africanum , and highlights the need to consider the particularities of each MTBC lineage for understanding the ecology and epidemiology of TB in Africa and globally., M.C. is supported by the Ramón y Cajal programme from the Ministerio de Ciencia, Innovación y Universidades. This work was supported by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) (research award to M.C.), Ministerio de Ciencia, Innovación y Universidades (grant number RTI2018-094399-A-I00 to M.C.) and Consellería de Educació de la Generalitat Valenciana (grant number SEJI/2019/011 to M.C.), the Swiss National Science Foundation (grants 310030_188888, IZRJZ3_164171, IZLSZ3_170834 and CRSII5_177163 to S. G.), the European Research Council (883582-ECOEVODRTB to S. G.) and Wellcome (grant number 097134/Z/11/Z to D. Y.-M).

Vibrio mimicus is an emerging pathogen, mainly associated with contaminated seafood consumption. However, little is known about its evolution, biodiversity, and pathogenic potential. This study analyzes the pan-, core, and accessory genomes of nine V. mimicus strains. The core genome yielded 2424 genes in chromosome I (ChI) and 822 genes in chromosome II (ChII), with an accessory genome comprising an average of 10.9% of the whole genome for ChI and 29% for ChII. Core genome phylogenetic trees were obtained, and V. mimicus ATCC-33654 strain was the closest to the outgroup in both chromosomes. Additionally, a phylogenetic study of eight conserved genes (ftsZ, gapA, gyrB, topA, rpoA, recA, mreB, and pyrH), including Vibrio cholerae, Vibrio parilis, Vibrio metoecus, and Vibrio caribbenthicus, clearly showed clade differentiation. The main virulence genes found in ChI corresponded with type I secretion proteins, extracellular components, flagellar proteins, and potential regulators, while, in ChII, the main categories were type-I secretion proteins, chemotaxis proteins, and antibiotic resistance proteins. The accessory genome was characterized by the presence of mobile elements and toxin encoding genes in both chromosomes. Based on the genome atlas, it was possible to characterize differential regions between strains. The pan-genome of V. mimicus encompassed 3539 genes for ChI and 2355 genes for ChII. These results give us an insight into the virulence and gene content of V. mimicus, as well as constitute the first approach to its diversity.

The emergence of resistance to azithromycin complicates treatment of Neisseria gonorrhoeae, the etiologic agent of gonorrhea. Substantial azithromycin resistance remains unexplained after accounting for known resistance mutations. Bacterial genome-wide association studies (GWAS) can identify novel resistance genes but must control for genetic confounders while maintaining power. Here, we show that compared to single-locus GWAS, conducting GWAS conditioned on known resistance mutations reduces the number of false positives and identifies a G70D mutation in the RplD 50S ribosomal protein L4 as significantly associated with increased azithromycin resistance (p-value = 1.08 × 10−11). We experimentally confirm our GWAS results and demonstrate that RplD G70D and other macrolide binding site mutations are prevalent (present in 5.42% of 4850 isolates) and widespread (identified in 21/65 countries across two decades). Overall, our findings demonstrate the utility of conditional associations for improving the performance of microbial GWAS and advance our understanding of the genetic basis of macrolide resistance., The mechanisms underlying resistance of Neisseria gonorrhoeae to the antibiotic azithromycin are incompletely understood. Here, Ma et al. conduct a conditional genome-wide association study to identify new resistance mutations and experimentally confirm that a mutation in ribosomal protein L4 confers increased resistance.

Randomized Controlled Trial European Collaborative Group: Raquel Abad Torreblanca, Lena Rós Ásmundsdóttir, Eszter Balla, Irith De Baetselier, Beatrice Bercot, Anna Carannante, Dominique Caugant, Maria José Borrego, Susanne Buder, Robert Cassar, Michelle Cole, Alje van Dam, Claudia Eder, Steen Hoffmann, Blazenka Hunjak, Samo Jeverica, Vesa Kirjavainen, Panayiota Maikanti-Charalambous, Vivi Miriagou, Beata Mlynarczyk-Bonikowska, Gatis Pakarna, Lynsey Patterson, Peter Pavlik, Monique Perrin, Jill Shepherd, Paola Stefanelli, Magnus Unemo, Jelena Viktorova, Hana Zákoucká European Collaborative Group: Portugal - Maria José Borrego, INSA. Objectives: Novel antimicrobials for treatment of gonorrhoea are imperative. The first-in-class spiropyrimidinetrione zoliflodacin is promising and currently in an international Phase 3 randomized controlled clinical trial (RCT) for treatment of uncomplicated gonorrhoea. We evaluated the in vitro activity of and the genetic conservation of the target (GyrB) and other potential zoliflodacin resistance determinants among 1209 consecutive clinical Neisseria gonorrhoeae isolates obtained from 25 EU/European Economic Area (EEA) countries in 2018 and compared the activity of zoliflodacin with that of therapeutic antimicrobials currently used. Methods: MICs of zoliflodacin, ceftriaxone, cefixime, azithromycin and ciprofloxacin were determined using an agar dilution technique for zoliflodacin or using MIC gradient strip tests or an agar dilution technique for the other antimicrobials. Genome sequences were available for 96.1% of isolates. Results: Zoliflodacin modal MIC, MIC50, MIC90 and MIC range were 0.125, 0.125, 0.125 and ≤0.004-0.5 mg/L, respectively. The resistance was 49.9%, 6.7%, 1.6% and 0.2% to ciprofloxacin, azithromycin, cefixime and ceftriaxone, respectively. Zoliflodacin did not show any cross-resistance to other tested antimicrobials. GyrB was highly conserved and no zoliflodacin gyrB resistance mutations were found. No fluoroquinolone target GyrA or ParC resistance mutations or mutations causing overexpression of the MtrCDE efflux pump substantially affected the MICs of zoliflodacin. Conclusions: The in vitro susceptibility to zoliflodacin was high and the zoliflodacin target GyrB was conserved among EU/EEA gonococcal isolates in 2018. This study supports further clinical development of zoliflodacin. However, additional zoliflodacin data regarding particularly the treatment of pharyngeal gonorrhoea, pharmacokinetics/pharmacodynamics and resistance selection, including suppression, would be valuable. The present work was funded by grants from the O¨rebro County Council Research Committee and the Foundation for Medical Research at O¨rebro University Hospital, Sweden. Work at the WHO Collaborating Centre for Gonorrhoea and Other STIs is additionally supported by grants to M.U. from the WHO and the Global Antibiotic Research and Development Partnership (GARDP). L.S.-B. was supported by the Li Ka Shing Foundation (Big Data Institute, University of Oxford, UK) and the Centre for Genomic Pathogen Surveillance (CGPS; http://pathogensurveillance.net) when this work was conceived. Currently, L.S.-B. is funded by Plan GenT (CDEI-06/ 20-B), Conselleria de Sanitat Universal i Salut Pu´blica, Generalitat Valenciana, Valencia, Spain. info:eu-repo/semantics/publishedVersion

ObjectivesSurveillance of antimicrobial resistance (AMR) in Neisseria gonorrhoeae, supported by molecular typing, ideally through genome sequencing, is imperative. We defined N. gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR) clonal complexes (CCs) and validated their usefulness in gonococcal AMR surveillance.MethodsAll NG-STAR alleles and STs available in the public database (https://ngstar.canada.ca/) were analysed using PHYLOViZ 2.0 to define CCs according to the closest founder ST with ≥5 identical alleles and founding ST with the highest number of links. The published 2013 European gonococcal dataset (n = 1054), the 2016 WHO reference strain panel (n = 14) and N. gonorrhoeae isolates with ceftriaxone resistance determinant penA-60.001 (n = 7) from several countries were used for validation.ResultsThe majority of the isolates (n = 1063) were designated to 71 CCs. The most common CC was CC90 (n = 194), followed by CC63 (n = 166), CC139 (n = 73), CC158 (n = 73) and CC127 (n = 62). CC90 included isolates belonging to the internationally spread MDR clone N. gonorrhoeae Multi-Antigen Sequence Typing (NG-MAST) G1407 (predominantly MLST ST1901). The ceftriaxone-resistant isolates with penA-60.001 (n = 7) belonged to CC73 or STs linking between CC90 and CC73 (ST233 and ST1133). Phylogenomic analysis revealed that NG-STAR CCs more appropriately correlated to phylogenomic AMR clusters compared with MLST STs, NG-MAST STs, NG-MAST genogroups and NG-STAR STs.ConclusionsNG-STAR CCs: are consistent with the gonococcal genome phylogeny; allow rapid visualizations with limited computational requirements; provide a simple, reproducible and portable nomenclature (for WGS and conventional Sanger sequencing data); and predict AMR lineages. Phenotypic AMR surveillance, supplemented with WGS, is imperative and NG-STAR CCs can effectively support this.

BackgroundMicrobial whole-genome sequencing (WGS) is now increasingly used to inform public health investigations of infectious disease. This approach has transformed our understanding of the global population structure of Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever. WGS has been particularly informative for understanding the global spread of multi-drug resistant (MDR) typhoid. As WGS capacity becomes more decentralised, there is a growing opportunity for collaboration and sharing of surveillance data within and between countries to inform disease control policies. This requires freely available, community driven tools that reduce the barriers to access genomic data for public health surveillance and that deliver genomic data on a global scale.MethodsHere we present the Pathogenwatch (https://pathogen.watch/styphi) scheme for S. Typhi, a web application enabling the rapid identification of genomic markers of antimicrobial resistance (AMR) and contextualization with public genomic data to identify high-risk clones at a population level. Data are delivered in single genome reports or in collections of genomes combined with geographic and other data using trees, maps and tables.ResultsWe show that the clustering of S. Typhi genomes in Pathogenwatch is comparable to established bioinformatics methods, and that genomic predictions of AMR are largely concordant with phenotypic drug susceptibility data. We demonstrate the public health utility of Pathogenwatch with examples selected from over 4,300 public genomes available in the application.ConclusionsPathogenwatch democratises genomic epidemiology of S. Typhi by providing an intuitive entry point for the analysis of WGS and linked epidemiological data, enabling international public health monitoring of the emergence and spread of high risk clones.

openaire: EC/H2020/742158/EU//SCARABEE Covariance-based discovery of polymorphisms under co-selective pressure or epistasis has received considerable recent attention in population genomics. Both statistical modeling of the population level covariation of alleles across the chromosome and model-free testing of dependencies between pairs of polymorphisms have been shown to successfully uncover patterns of selection in bacterial populations. Here we introduce a model-free method, SpydrPick, whose computational efficiency enables analysis at the scale of pan-genomes of many bacteria. SpydrPick incorporates an efficient correction for population structure, which adjusts for the phylogenetic signal in the data without requiring an explicit phylogenetic tree. We also introduce a new type of visualization of the results similar to the Manhattan plots used in genome-wide association studies, which enables rapid exploration of the identified signals of co-evolution. Simulations demonstrate the usefulness of our method and give some insight to when this type of analysis is most likely to be successful. Application of the method to large population genomic datasets of two major human pathogens, Streptococcus pneumoniae and Neisseria meningitidis, revealed both previously identified and novel putative targets of co-selection related to virulence and antibiotic resistance, highlighting the potential of this approach to drive molecular discoveries, even in the absence of phenotypic data.

The emergence of resistance to azithromycin complicates treatment of N. gonorrhoeae, the etiologic agent of gonorrhea. Population genomic analyses of clinical isolates have demonstrated that some azithromycin resistance remains unexplained after accounting for the contributions of known resistance mutations in the 23S rRNA and the MtrCDE efflux pump. Bacterial genome-wide association studies (GWAS) offer a promising approach for identifying novel resistance genes but must adequately address the challenge of controlling for genetic confounders while maintaining power to detect variants with lower effect sizes. Compared to a standard univariate GWAS, conducting GWAS conditioned on known resistance mutations with high effect sizes substantially reduced the number of variants that reached genome-wide significance and identified a G70D mutation in the 50S ribosomal protein L4 (encoded by the gene rplD) as significantly associated with increased azithromycin minimum inhibitory concentrations (β = 1.03, 95% CI [0.76, 1.30]). The role and prevalence of these rplD mutations in conferring macrolide resistance in N. gonorrhoeae had been unclear. Here, we experimentally confirmed our GWAS results, identified other resistance-associated mutations in RplD, and showed that in total these RplD binding site mutations are prevalent (present in 5.42% of 4850 isolates) and geographically and temporally widespread (identified in 21/65 countries across two decades). Overall, our findings demonstrate the utility of conditional associations for improving the performance of microbial GWAS and advance our understanding of the genetic basis of macrolide resistance in a prevalent multidrug-resistant pathogen.

Neisseria gonorrhoeaeis an urgent public health threat due to rapidly increasing incidence and antibiotic resistance. In contrast with the trend of increasing resistance, clinical isolates that have reverted to susceptibility regularly appear, prompting questions about which pressures compete with antibiotics to shape gonococcal evolution. Here, we used genome-wide association on the largest collection ofN. gonorrhoeaeisolates to date (n=4852) to identify loss-of-function (LOF) mutations in the efflux pumpmtrCDEoperon as a mechanism of increased antibiotic susceptibility and demonstrate that these mutations are overrepresented in cervical isolates relative to urethral isolates (odds ratio (OR) = 3.74, 95% CI [1.98-6.70]). In support of a model in which pump expression incurs a fitness cost in this niche, cervical isolates were also enriched relative to urethral isolates in LOF mutations in themtrCDEactivatormtrA(OR = 8.60, 95% CI [4.96-14.57]) and infarA,a subunit of the FarAB efflux pump (OR = 6.25, 95% CI [3.90-9.83]). In total, approximately 2 in 5 cervical isolates (42.6%) contained a LOF mutation in either the efflux pump componentsmtrCorfarAor the activatormtrA.Our findings extend beyondN. gonorrhoeaeto otherNeisseria:mtrCLOF mutations are rare (N. meningitidisin a collection of 14,798 genomes but enriched in a heterosexual urethritis-associated lineage (8.6%, p = 9.90×10−5), indicating that efflux pump downregulation contributes broadly to the adaptation of pathogenicNeisseriato the female urogenital tract. Overall, our findings highlight the impact of integrating microbial population genomics with host metadata and demonstrate how host environmental pressures can lead to increased antibiotic susceptibility.

Restriction-Modification systems (RMS) are one of the main mechanisms of defence against foreign DNA invasion and can have an important role in the regulation of gene expression. The obligate human pathogen Neisseria gonorrhoeae carries one of the highest loads of RMS in its genome; between 13 to 15 of the three main types. Previous work has described their organization in the reference genome FA1090 and has experimentally inferred the associated methylated motifs. Here, we studied the structure of RMS and target methylated motifs in 25 gonococcal strains sequenced with Single Molecule Real-Time (SMRT) technology, which provides data on DNA modification. The results showed a variable picture of active RMS in different strains, with phase variation switching the activity of Type III RMS, and both the activity and specificity of a Type I RMS. Interestingly, the Dam methylase was found in place of the NgoAXI endonuclease in two of the strains, despite being previously thought to be absent in the gonococcus. We also identified the real methylation target of NgoAX as 5’-GCAGA-3’, different from that previously described. Results from this work give further insights into the diversity and dynamics of RMS and methylation patterns in N. gonorrhoeae.

The sexually transmitted pathogen Neisseria gonorrhoeae is regarded as being on the way to becoming an untreatable superbug. Despite its clinical importance, little is known about its emergence and evolution, and how this corresponds with the introduction of antimicrobials. We present a genome-based phylogeographical analysis of 419 gonococcal isolates from across the globe. Results indicate that modern gonococci originated in Europe or Africa, possibly as late as the sixteenth century and subsequently disseminated globally. We provide evidence that the modern gonococcal population has been shaped by antimicrobial treatment of sexually transmitted infections as well as other infections, leading to the emergence of two major lineages with different evolutionary strategies. The well-described multidrug-resistant lineage is associated with high rates of homologous recombination and infection in high-risk sexual networks. A second, multisusceptible lineage is more associated with heterosexual networks, with potential implications for infection control.

14 páginas, 6 figuras, Models on how bacterial lineages differentiate increase our understanding of early bacterial speciation events and the genetic loci involved. Here, we analyze the population genomics events leading to the emergence of the tuberculosis pathogen. The emergence is characterized by a combination of recombination events involving core pathogenesis functions and purifying selection on early diverging loci. We identify the phoR gene, the sensor kinase of a two-component system involved in virulence, as a key functional player subject to pervasive positive selection after the divergence of the Mycobacterium tuberculosis complex from its ancestor. Previous evidence showed that phoR mutations played a central role in the adaptation of the pathogen to different host species. Now, we show that phoR mutations have been under selection during the early spread of human tuberculosis, during later expansions, and in ongoing transmission events. Our results show that linking pathogen evolution across evolutionary and epidemiological time scales points to past and present virulence determinants., This work was funded by projects of the European Research Council (638553-TB-ACCELERATE) and Ministerio de Economía y Competitividad (Spanish government) research grant SAF2016-77346-R (to I.C.); BFU2014-58656-R and BFU2017-89594-R from Ministerio de Economía y Competitividad (Spanish government) and PROMETEO/2016/122 from Generalitat Valenciana (to F.G.-C); and the Swiss National Science Foundation (grants 310030_166687, IZRJZ3_164171, IZLSZ3_170834, and CRSII5_177163), the European Research Council (309540-EVODRTB), and SystemsX.ch (to S.G.). Á.C.-O. is the recipient of an FPU fellowship from Ministerio de Ciencia, Innovación y Universidades FPU13/00913 (Spanish government). L.S.-B. was funded by Wellcome grant number 098051.

Objectives Gonorrhoea and MDR Neisseria gonorrhoeae remain public health concerns globally. Enhanced, quality-assured, gonococcal antimicrobial resistance (AMR) surveillance is essential worldwide. The WHO global Gonococcal Antimicrobial Surveillance Programme (GASP) was relaunched in 2009. We describe the phenotypic, genetic and reference genome characteristics of the 2016 WHO gonococcal reference strains intended for quality assurance in the WHO global GASP, other GASPs, diagnostics and research worldwide. Methods The 2016 WHO reference strains (n = 14) constitute the eight 2008 WHO reference strains and six novel strains. The novel strains represent low-level to high-level cephalosporin resistance, high-level azithromycin resistance and a porA mutant. All strains were comprehensively characterized for antibiogram (n = 23), serovar, prolyliminopeptidase, plasmid types, molecular AMR determinants, N. gonorrhoeae multiantigen sequence typing STs and MLST STs. Complete reference genomes were produced using single-molecule PacBio sequencing. Results The reference strains represented all available phenotypes, susceptible and resistant, to antimicrobials previously and currently used or considered for future use in gonorrhoea treatment. All corresponding resistance genotypes and molecular epidemiological types were described. Fully characterized, annotated and finished references genomes (n = 14) were presented. Conclusions The 2016 WHO gonococcal reference strains are intended for internal and external quality assurance and quality control in laboratory investigations, particularly in the WHO global GASP and other GASPs, but also in phenotypic (e.g. culture, species determination) and molecular diagnostics, molecular AMR detection, molecular epidemiology and as fully characterized, annotated and finished reference genomes in WGS analysis, transcriptomics, proteomics and other molecular technologies and data analysis.

Gonorrhoea infections are on the increase and strains that are resistant to all antimicrobials used to treat the disease have been found worldwide. These observations encouraged the World Health Organization to include Neisseria gonorrhoeae on their list of high-priority organisms in need of new treatments. Fortunately, concurrent resistance to both antimicrobials used in dual therapy is still rare. The fight against antimicrobial resistance (AMR) must begin from an understanding of how it evolves and spreads in sexual networks. Genome-based analyses have allowed the study of the gonococcal population dynamics and transmission, giving a novel perspective on AMR gonorrhoea. Here, we will review past, present and future treatment options for gonorrhoea and explain how genomics is helping to increase our understanding of the changing AMR and transmission landscape. This article contains data hosted by Microreact.

[Background]: Bovine tuberculosis (bTB) caused by Mycobacterium bovis is a re-emerging problem in both livestock and humans. The association of some M. bovis strains with hyper-virulence, MDR-TB and disseminated disease makes it imperative to understand the biology of the pathogen., [Methods]: Mycobacterium bovis (15) among 1755 M. tuberculosis complex (MTBC) isolated between 2012 and 2014 were characterized and analyzed for associated patient demography and other risk factors. Five of the M. bovis isolates were whole-genome sequenced and comparatively analyzed against a global collection of published M. bovis genomes., [Results]: Mycobacterium bovis was isolated from 3/560(0.5%) females and 12/1195(1.0%) males with pulmonary TB. The average age of M. bovis infected cases was 46.8 years (7-72years). TB patients from the Northern region of Ghana (1.9%;4/212) had a higher rate of infection with M. bovis (OR = 2.7,p = 0.0968) compared to those from the Greater Accra region (0.7%;11/1543). Among TB patients with available HIV status, the odds of isolating M. bovis from HIV patients (2/119) was 3.3 higher relative to non-HIV patients (4/774). Direct contact with livestock or their unpasteurized products was significantly associated with bTB (p, [Conclusion]: Our data indicate potential zoonotic transmission of bTB in Ghana and hence calls for intensified public education on bTB, especially among risk groups., This work was supported by the Wellcome Trust Intermediate Fellowship awarded to DYM (Grant Number 097134/Z/11/Z).

This month’s Genome Watch examines how novel machine learning-enabled molecular diagnostic approaches can predict antibiotic resistance when genetic variation falls short. This month’s Genome Watch examines how novel machine learning-enabled molecular diagnostic approaches can predict antibiotic resistance when ge-netic variation falls short.

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is common, compromising gonorrhoea treatment internationally. Rapid characterisation of AMR strains could ensure appropriate and personalised treatment, and support identification and investigation of gonorrhoea outbreaks in nearly real-time. Whole-genome sequencing is ideal for investigation of emergence and dissemination of AMR determinants, predicting AMR, in the gonococcal population and spread of AMR strains in the human population. The novel, rapid and revolutionary long-read sequencer MinION is a small hand-held device that generates bacterial genomes within one day. However, accuracy of MinION reads has been suboptimal for many objectives and the MinION has not been evaluated for gonococci. In this first MinION study for gonococci, we show that MinION-derived sequences analysed with existing open-access, web-based sequence analysis tools are not sufficiently accurate to identify key gonococcal AMR determinants. Nevertheless, using an in house-developed CLC Genomics Workbench including de novo assembly and optimised BLAST algorithms, we show that 2D ONT-derived sequences can be used for accurate prediction of decreased susceptibility or resistance to recommended antimicrobials in gonococcal isolates. We also show that the 2D ONT-derived sequences are useful for rapid phylogenomic-based molecular epidemiological investigations, and, in hybrid assemblies with Illumina sequences, for producing contiguous assemblies and finished reference genomes.

Antimicrobial resistant (AMR) Neisseria gonorrhoeae strains are common and compromise gonorrhoea treatment internationally. Rapid identification and characterisation of AMR gonococcal strains could ensure appropriate and even personalised treatment, and support identification and investigation of gonorrhoea outbreaks in nearly real-time. Whole-genome sequencing is ideal for investigation of the emergence and dissemination of AMR determinants that predict AMR in the gonococcal population and spread of AMR strains in the human population. The novel, rapid and revolutionary long-read sequencer MinION is a small hand-held device that can generate bacterial genomes within one day. However, the accuracy of MinION reads has been suboptimal for many objectives and the MinION has not been evaluated for gonococci. In this first MinION study for gonococci, we show that MinION-derived sequences analysed with existing open-access, web-based sequence analysis tools are not sufficiently accurate to identify key gonococcal AMR determinants. Nevertheless, using an in house-developed CLC Genomics Workbench, we show that ONT-derived sequences can be used for accurate prediction of decreased susceptibility or resistance to recommended therapeutic antimicrobials. We also show that the ONT-derived sequences can be useful for rapid phylogenomic-based molecular epidemiological investigations, and, in hybrid assemblies with Illumina sequences, for producing contiguous assemblies and finished reference genomes.

The sexually transmitted pathogen Neisseria gonorrhoeae is regarded as being on the way to becoming an untreatable superbug. Despite its clinical importance, little is known about its emergence and evolution, and how this corresponds with the introduction of antimicrobials. We present a genome-based phylogeographic analysis of 419 gonococcal isolates from across the globe. Results indicate that modern gonococci originated in Europe or Africa as late as the 16thcentury and subsequently disseminated globally. We provide evidence that the modern gonococcal population has been shaped by antimicrobial treatment of sexually transmitted and other infections, leading to the emergence of two major lineages with different evolutionary strategies. The well-described multi-resistant lineage is associated with high rates of homologous recombination and infection in high-risk sexual networks where antimicrobial treatment is frequent. A second, multi-susceptible lineage associated with heterosexual networks, where asymptomatic infection is more common, was also identified, with potential implications for infection control.

Mycobacterium africanum(Maf) causes up to half of human tuberculosis in West Africa, but little is known on this pathogen. We compared the genomes of 253Mafclinical isolates from Ghana, including both L5 and L6. We found that the genomic diversity of L6 was higher than in L5, and the selection pressures differed between both groups. Regulatory proteins appeared to evolve neutrally in L5 but under purifying selection in L6. Conversely, human T cell epitopes were under purifying selection in L5, but under positive selection in L6. Although only 10% of the T cell epitopes were variable, mutations were mostly lineage-specific. Our findings indicate thatMafL5 and L6 are genomically distinct, possibly reflecting different ecological niches.

Antimicrobial resistance (AMR) is one of the major threats to human and animal health worldwide, yet few high-throughput tools exist to analyse and predict the resistance of a bacterial isolate from sequencing data. Here we present a new tool, ARIBA, that identifies AMR-associated genes and single nucleotide polymorphisms directly from short reads, and generates detailed and customisable output. The accuracy and advantages of ARIBA over other tools are demonstrated on three datasets from Gram-positive and Gram-negative bacteria, with ARIBA outperforming existing methods. ARIBA is available at https://github.com/sanger-pathogens/ariba.

Legionella pneumophila is an environmental bacterium and the causative agent of Legionnaires’ disease. Previous genomic studies have shown that recombination accounts for a high proportion (>96%) of diversity within several major disease-associated sequence types (STs) of L. pneumophila. This suggests that recombination represents a potentially important force shaping adaptation and virulence. Despite this, little is known about the biological effects of recombination in L. pneumophila, particularly with regards to homologous recombination (whereby genes are replaced with alternative allelic variants). Using newly available population genomic data, we have disentangled events arising from homologous and non-homologous recombination in six major disease-associated STs of L. pneumophila (subsp. pneumophila), and subsequently performed a detailed characterisation of the dynamics and impact of homologous recombination. We identified genomic “hotspots” of homologous recombination that include regions containing outer membrane proteins, the lipopolysaccharide (LPS) region and Dot/Icm effectors, which provide interesting clues to the selection pressures faced by L. pneumophila. Inference of the origin of the recombined regions showed that isolates have most frequently imported DNA from isolates belonging to their own clade, but also occasionally from other major clades of the same subspecies. This supports the hypothesis that the possibility for horizontal exchange of new adaptations between major clades of the subspecies may have been a critical factor in the recent emergence of several clinically important STs from diverse genomic backgrounds. However, acquisition of recombined regions from another subspecies, L. pneumophila subsp. fraseri, was rarely observed, suggesting the existence of a recombination barrier and/or the possibility of ongoing speciation between the two subspecies. Finally, we suggest that multi-fragment recombination may occur in L. pneumophila, whereby multiple non-contiguous segments that originate from the same molecule of donor DNA are imported into a recipient genome during a single episode of recombination., Author summary Legionella pneumophila is an environmental bacterium that causes Legionnaires’ disease, a serious and potentially fatal pneumonia. Previous studies have shown that members of this species undergo a process called recombination, whereby DNA is imported from another bacterial cell into the recipient genome. The imported DNA can either replace an equivalent segment of the genome (homologous recombination) or can comprise novel genes that are new to the recipient genome (non-homologous recombination). Whilst recombination plays an undoubtedly important role in L. pneumophila evolution, accounting for more than 96% of the diversity observed within some lineages, little is known about its biological impact. In this study, we performed a detailed characterisation of the dynamics and effect of homologous recombination on L. pneumophila evolution in six clinically important lineages of L. pneumophila. We identified “hotspot” regions of the genome in which an excess of homologous recombination events was observed, which provided important clues to the selection pressures faced by L. pneumophila. By determining the donors of the recombined regions, we also revealed that recombination has occurred most frequently between isolates from the same clade, but also occurred between isolates from different major clades. This demonstrates the possibility of new adaptations arising in one lineage and being transferred to another distantly related lineage, which we predict has been an important factor in the emergence of several major disease-causing strains from diverse genomic backgrounds.

Background Chlamydia abortus (formerly Chlamydophila abortus) is an economically important livestock pathogen, causing ovine enzootic abortion (OEA), and can also cause zoonotic infections in humans affecting pregnancy outcome. Large-scale genomic studies on other chlamydial species are giving insights into the biology of these organisms but have not yet been performed on C. abortus. Our aim was to investigate a broad collection of European isolates of C. abortus, using next generation sequencing methods, looking at diversity, geographic distribution and genome dynamics. Results Whole genome sequencing was performed on our collection of 57 C. abortus isolates originating primarily from the UK, Germany, France and Greece, but also from Tunisia, Namibia and the USA. Phylogenetic analysis of a total of 64 genomes shows a deep structural division within the C. abortus species with a major clade displaying limited diversity, in addition to a branch carrying two more distantly related Greek isolates, LLG and POS. Within the major clade, seven further phylogenetic groups can be identified, demonstrating geographical associations. The number of variable nucleotide positions across the sampled isolates is significantly lower than those published for C. trachomatis and C. psittaci. No recombination was identified within C. abortus, and no plasmid was found. Analysis of pseudogenes showed lineage specific loss of some functions, notably with several Pmp and TMH/Inc proteins predicted to be inactivated in many of the isolates studied. Conclusions The diversity within C. abortus appears to be much lower compared to other species within the genus. There are strong geographical signatures within the phylogeny, indicating clonal expansion within areas of limited livestock transport. No recombination has been identified within this species, showing that different species of Chlamydia may demonstrate different evolutionary dynamics, and that the genome of C. abortus is highly stable. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3657-y) contains supplementary material, which is available to authorized users.

An epidemic of post-surgical wound infections, caused by a non-tuberculous mycobacterium, has been on-going in Brazil. It has been unclear whether one or multiple lineages are responsible and whether their wide geographical distribution across Brazil is due to spread from a single point source or is the result of human-mediated transmission. 188 isolates, collected from nine Brazilian states, were whole genome sequenced and analysed using phylogenetic and comparative genomic approaches. The isolates from Brazil formed a single clade, which was estimated to have emerged in 2003. We observed temporal and geographic structure within the lineage that enabled us to infer the movement of sub-lineages across Brazil. The genome size of the Brazilian lineage was reduced relative to most strains in the three subspecies of Mycobacterium abscessus and contained a novel plasmid, pMAB02, in addition to the previously described pMAB01 plasmid. One lineage, which emerged just prior to the initial outbreak, is responsible for the epidemic of post-surgical wound infections in Brazil. Phylogenetic analysis indicates that multiple transmission events led to its spread. The presence of a novel plasmid and the reduced genome size suggest that the lineage has undergone adaptation to the surgical niche.

This month's Genome Watch highlights how culture-independent selective enrichment approaches coupled to whole-genome sequencing enable the analysis of unculturable microorganisms. This month's Genome Watch highlights how culture-independent selective enrichment approaches are now being coupled to whole-genome sequencing to enable the analysis of unculturable microorganisms.

Fundamentos: La epidemiología molecular es una nueva disciplina que permite la integración de la información sobre la variabilidad genética de patógenos infecciosos con su difusión en la población y subgrupos de la misma incluyendo, por ejemplo, las mutaciones de resistencia a antibióticos y antivirales. El objetivo es conocer qué posibles diferencias existe en las características genéticas de los agentes infecciosos que afectan a las poblaciones inmigrante y autóctoctona en España. Métodos: Se revisaron artículos originales publicados entre 1998-2013, con las palabras clave "epidemiología molecular", "tipado molecular", "secuenciación", "inmigrante", "España". Resultados: De un total de 267 artículos identificados inicialmente, 50 pasaron los diferentes filtros establecidos. De ellos, 36 analizan las infecciones por Mycobacterium tuberculosis y VIH, seguidos de los que analizan infecciones por Staphylococcus aureus (3) y el Virus de la Hepatitis B (3). Conclusiones: Los objetivos principales de estos trabajos fueron el tipado del patógeno y la determinación de la frecuencia de mutaciones de resistencia. Los estudios más frecuentes correspondieron a cohortes retrospectivas, seguidos por los estudios ecológicos y los ensayos clínicos. En general los estudios son descriptivos y su ámbito por el tipo y tamaño de muestra es bastante restringido. En varios se determina que las cepas o variantes del patógeno encontradas en inmigrantes tienen su origen más probable en sus países de origen, si bien otros también ponen de manifiesto la transmisión desde la población autóctona a la inmigrante.

The abrupt onslaught of the syphilis pandemic that started in the late fifteenth century established this devastating infectious disease as one of the most feared in human history1 . Surprisingly, despite the availability of effective antibiotic treatment since the mid-twentieth century, this bacterial infection, which is caused by Treponema pallidum subsp. pallidum (TPA), has been re-emerging globally in the last few decades with an estimated 10.6 million cases in 2008 (ref. 2). Although resistance to penicillin has not yet been identified, an increasing number of strains fail to respond to the secondline antibiotic azithromycin3. Little is known about the genetic patterns in current infections or the evolutionary origins of the disease due to the low quantities of treponemal DNA in clinical samples and difficulties in cultivating the pathogen4. Here, we used DNA capture and whole-genome sequencing to successfully interrogate genome-wide variation from syphilis patient specimens, combined with laboratory samples of TPA and two other subspecies. Phylogenetic comparisons based on the sequenced genomes indicate that the TPA strains examined share a common ancestor after the fifteenth century, within the early modern era. Moreover, most contemporary strains are azithromycin-resistant and are members of a globally dominant cluster, named here as SS14-Ω. The cluster diversified from a common ancestor in the mid-twentieth century subsequent to the discovery of antibiotics. Its recent phylogenetic divergence and global presence point to the emergence of a pandemic strain cluster. Fil: Arora, Natasha. Universitat Zurich; Suiza Fil: Schuenemann, Verena J.. Eberhard Karls Universität Tübingen. Institute For Archaeological Sciences.; Alemania Fil: Jäger, Hünter. Eberhard Karls Universität Tübingen.; Alemania Fil: Peltzer, Alexander. Eberhard Karls Universität Tübingen.; Alemania Fil: Seitz, Alexander. Eberhard Karls Universität Tübingen.; Alemania Fil: Herbig, Alexander. Eberhard Karls Universität Tübingen.; Alemania Fil: Strouhal, Michal. Masaryk University; República Checa Fil: Grillová, Linda. Masaryk University; República Checa Fil: Sánchez Busó, Leonor. Universidad de Valencia; España. University of Cambridge; Reino Unido Fil: Kühnert, Denise. Universitat Zurich; Suiza Fil: Bos, Kirsten I.. Eberhard Karls Universität Tübingen. Institute For Archaeological Sciences.; Alemania Fil: Davis Rivero, Leyla. Universitat Zurich; Suiza Fil: Mikalová, Lenka. Masaryk University; República Checa Fil: Bruisten, Sylvia. Public Health Laboratory. Department of Infectious Diseases; Países Bajos Fil: Komericki, Peter. Medical University of Graz; Austria Fil: French, Patrick. The Mortimer Market Centre ; Reino Unido Fil: Grant, Paul R.. University College London; Estados Unidos Fil: Pando, María de los Ángeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina. Universidad de Buenos Aires; Argentina Fil: Gallo Vaulet, Maria Lucia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina Fil: Rodríguez Fermepin, Marcelo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina Fil: Martinez, Antonio. Hospital General Universitario de Valencia; España Fil: Lara, Arturo Centurión. University of Washington; Estados Unidos Fil: Giacani, Lorenzo. University of Washington; Estados Unidos Fil: Norris, Steven J.. UTHealth McGovern Medical School. Department of Pathology and Laboratory Medicine; Estados Unidos Fil: Smajs, David. Masaryk University; República Checa Fil: Bosshard, Philipp P.. Universitat Zurich; Suiza Fil: González Candelas, Fernando. Universidad de Valencia; España Fil: Nieselt, Kay. Eberhard Karls Universität Tübingen.; Alemania Fil: Krause, Johannes. Eberhard Karls Universität Tübingen.; Alemania Fil: Bagheri, Homayoun C.. Universitat Zurich; Suiza

Syphilis swept across the world in the 16th century as one of most prominent documented pandemics and is re-emerging worldwide despite the availability of effective antibiotics. Little is known about the genetic patterns in current infections or the evolutionary origins of the disease due to the non-cultivable and clonal nature of the causative bacterium Treponema pallidum subsp. pallidum. In this study, we used DNA capture and next generation sequencing to obtain whole genome data from syphilis patient specimens and from treponemes propagated in laboratory settings. Phylogenetic analyses indicate that the syphilis strains examined here share a common ancestor after the 15th century. Moreover, most contemporary strains are azithromycin resistant and members of a globally dominant cluster named here as SS14-Ω. This cluster diversified from a common ancestor in the mid-20th century and has the population genetic and epidemiological features indicative of the emergence of a pandemic strain cluster.

The study of outbreaks of infectious diseases has been revolutionized by the current availability of fast and efficient, high-throughput methods capable of yielding the nucleotide sequence of complete genomes of viruses and bacteria within a few days, or even hours. These methods are replacing previous molecular techniques which have been used for the past 30 years, although many of them are still the usual approach for many such investigations. Here we review the major technologies currently in use for high-throughput sequencing of bacterial genomes emphasizing their advantages and drawbacks for the analysis of outbreaks. The use of more efficient methods does not necessarily mean that all the problems in the study of outbreaks are automatically solved. In fact, because these methods are capable of revealing genetic variation at an unprecedented level and scale they also pose new challenges for the interpretation of the resulting data. We analyze some of these new challenges, especially those in which the short term evolution of microorganism plays an important role in understanding and interpreting the results and, quite often, in reconciling them with those derived from classical epidemiological analyses. Finally, we exemplify the advantages of using complete genome analysis with two cases, involving outbreaks of Mycobacterium tuberculosis and Legionella pneumophila.

[EN] Legionella pneumophila is a strictly environmental and opportunistic pathogen that can cause severe pneumonia after inhalation of aerosols with enough bacterial load. Outbreaks and sporadic cases are usually localized in temperate environments, and the reservoirs are often water-related sources where biofilms are created. The existence of non-cultivable forms of the bacteria increases the risk for public health, as culture-based methods may miss them, thus complicating the environmental investigations of the sources. Genetic classification through the Sequence-Based Typing (SBT) technique allowed an increased discrimination among L. pneumophila strains compared to previous methods. SBT data can also be used for genetic variability and population structure studies, but a more exhaustive analysis can be performed using high-throughput genome sequencing strategies. This thesis describes the use of both SBT and genomic sequencing to evaluate and provide solutions to different public health needs in L. pneumophila epidemiology. We have focused in the Comunidad Valenciana (CV), the second region in Spain with the highest incidence of Legionellosis, with special interest in the city of Alcoy, where recurrent outbreaks have occurred since 1998. Firstly, SBT data were used to gain a deeper insight into the genetic variability and distribution of the most abundant Sequence Types (ST) in the CV area. We have shown that the level of variability in this region is comparable to that from other countries, revealing the existence of both locally and broadly extended profiles. Approximately half of the observed genetic diversity was found to result from geographical and temporal structure. Secondly, L. pneumophila detection from environmental sources remains a challenge for public health. A comparison between water and biofilm samples using a sensitive touchdown PCR (TD-PCR) strategy revealed that the use of biofilms increased by ten-fold the detection rate. This method allowed evaluating the hidden uncultivable L. pneumophila diversity in the locality of Alcoy and the real-time investigation of a Legionellosis outbreak affecting a hotel in Calpe (Southeast of Spain) in 2012. Thirdly, genomic sequencing was applied to a set of 69 strains isolated during 13 outbreaks occurred in Alcoy in the period 1999-2010, mainly the recurrent ST578. Higher intra-outbreak variability than expected was observed, pointing to the potential existence of multiple sources in this endemic area or high environmental diversity. Interestingly, above 98% of the genomic variability in this ST was found as being incorporated through recombination processes rather than through point mutations. Finally, a metagenomic analysis of environmental biofilms from Alcoy revealed a microbial community dominated by Proteobacteria, Cyanobacteria, Actinobacteria and Bacteroidetes. Despite the known endemism of Legionella in this area, the genus was only found in a relative abundance ranging 0.01-0.07%, which explains the low recovery from environmental sources. In summary, the results from this thesis can benefit public health efforts to control this pathogen in the environment, as we provide new insight into its molecular epidemiology, with immediate applications to surveillance and outbreak investigations., [ES] Legionella pneumophila es un patógeno oportunista estrictamente ambiental capaz de causar neumonía debido a la inhalación de aerosoles con suficiente carga bacteriana. Los brotes y casos esporádicos suelen producirse en ambientes templados y los reservorios encontrarse en zonas con agua donde pueden crearse biopelículas microbianas. La existencia de formas no cultivables de la bacteria aumenta el riesgo para la salud pública, ya que los métodos estándar basados en cultivo microbiológico no pueden detectarlas, complicando las investigaciones ambientales. La clasificación genética basada en el método Sequence-Based Typing (SBT) permite un mayor poder de discriminación entre cepas de L. pneumophila en comparación con métodos previos. Los datos derivados del SBT pueden utilizarse para estudios de variabilidad genética y estructura poblacional. Sin embargo, puede llevarse a cabo un análisis más exhaustivo mediante técnicas de secuenciación genómica de alto rendimiento. Esta tesis describe la utilización tanto de SBT como de secuenciación genómica para evaluar e incluso proponer soluciones a diferentes necesidades en salud pública relacionadas con la epidemiología de L. pneumophila. Nos centramos en la Comunidad Valenciana (CV), la segunda región en España con mayor incidencia de Legionelosis, con especial interés en la localidad de Alcoy, donde ocurren brotes de forma recurrente. En primer lugar, utilizamos datos derivados de SBT para conocer mejor la variabilidad y la distribución de los perfiles genéticos (Sequence Types, ST) en el área de la CV. Mostramos que el nivel de variabilidad en sólo esta región es comparable a la de otros países, con perfiles extendidos local y globalmente. Aproximadamente la mitad de la diversidad genética observada se estima que procede de estructuración geográfica y temporal. En segundo lugar, la detección de L. pneumophila a partir de fuentes ambientales sigue suponiendo un reto para la salud pública. En esta tesis realizamos una comparación entre la detección mediante touchdown PCR (TD-PCR) a partir de muestras de agua y biopelículas microbianas y mostramos que estas últimas proporcionan un aumento de 10 veces en la tasa de detección de la bacteria. Este método permitió evaluar la diversidad no cultivable de L. pneumophila en la localidad de Alcoy y la investigación a tiempo real de un brote en un hotel en Calpe (Sudeste de España) en 2012. A continuación, aplicamos la secuenciación genómica a 69 cepas aisladas durante 13 brotes ocurridos en Alcoy en el período 1999-2010, principalmente el recurrente ST578. Se observó mayor variabilidad entre cepas de un mismo brote que la esperada, lo cual apunta a la existencia potencial de múltiples fuentes en este área, o alta diversidad ambiental. Además, se observó que más del 98% de la variabilidad genómica fue introducida por procesos de recombinación y no de mutación puntual. Finalmente, se realizó un análisis metagenómico de biopelículas ambientales recogidas en Alcoy. Se encontró que la comunidad está dominada por Proteobacteria, Cyanobacteria, Actinobacteria y Bacteroidetes. A pesar del conocido endemismo de Legionella en el área, este género sólo se encontró en una abundancia relativa entre 0.01-0.07%, lo cual explica su baja tasa de recuperación a partir de muestras ambientales. En resumen, los resultados de esta tesis pueden ser de utilidad para los programas de control de este patógeno llevados a cabo por las autoridades de salud pública, ya que proporcionan una nueva percepción de su epidemiología molecular, con aplicación inmediata a la vigilancia e investigación de brotes., [CAT] Legionella pneumophila és un patogen oportunista estrictament ambiental capaç d'ocasionar pneumònia degut a la inhalació d'aerosols amb la suficient carga bacteriana. Els brots i casos esporàdics solen ocórrer en ambients temperats, i els reservoris solen trobar-se en zones amb aigua on poden crear-se biopel·lícules microbianes. La existència de formes no cultivables del bacteri augmenten el risc per a la salut pública, ja que els mètodes estàndard basats en el cultiu microbiològic no poden detectar-les, complicant les investigacions ambientals. La classificació genètica basada en el mètode Sequence-Based Typing (SBT) permet un major poder de discriminació entre soques de L. pneumophila en comparació amb previs mètodes. Les dades derivades del SBT poden utilitzar-se per a estudis de variabilitat genètica i estructura poblacional, però un anàlisis més exhaustiu pot dur-se a terme a través de tècniques de seqüenciació genòmica d'alt rendiment. Esta tesis descriu la utilització tant del SBT com de la seqüenciació genòmica per a avaluar i proposar solucions a diferents necessitats en salut pública relacionades amb l'epidemiologia de L. pneumophila. Ens centrem en la Comunitat Valenciana (CV), la segona regió d'Espanya amb la major incidència de Legionel·losi, amb especial interès en la localitat d'Alcoi, on els brots ocorren de forma recurrent des de 1998. Primer, hem utilitzat dades derivades del SBT per a conèixer millor la variabilitat i la distribució dels perfils genètics (Sequence Types, ST) en l'àrea de la CV. Mostrem que el nivell de variabilitat en només aquesta regió és comparable a la d'altres països, amb perfils estesos tant de forma local com més amplia. Aproximadament la meitat de la diversitat genètica observada s'estima que procedeix d'estructuració geogràfica i temporal. Segon, la detecció de L. pneumophila a partir de fonts ambientals continua suposant un repte per a la salut pública. En aquesta tesis realitzem una comparació entre la detecció mitjançant touchdown PCR (TD-PCR) a partir de mostres d'aigua i biopel·lícules microbianes i mostrem que aquestes últimes proporcionen un augment de deu vegades en la tassa de detecció. A més, aquest mètode ens va permetre avaluar la diversitat no cultivable de L. pneumophila a la localitat d'Alcoi i la investigació a temps real d'un brot de Legionelosis que va afectar a un hotel en Calp (Sud-est d'Espanya) a l'any 2012. Tercer, vam aplicar la seqüenciació genòmica a 69 soques aïllades durant 13 brots ocorreguts a Alcoi en el període 1999-2010, principalment el recurrent ST578. Es va observar una major variabilitat entre soques d'un mateix brot de l'esperada, apuntant a l'existència potencial de múltiples fonts en aquesta àrea, considerada endèmica, o alta diversitat ambiental. A més, es va observar que més del 98% de la variabilitat genòmica havia sigut introduïda a partir de processos de recombinació i no de mutació puntual. Finalment, es va realitzar una anàlisi metagenòmica de biopel·lícules ambientals recollides a Alcoi. Varem trobar que la comunitat està dominada per Proteobacteria, Cyanobacteria, Actinobacteria i Bacteroidetes. A pesar del conegut endemisme de Legionella en l'àrea, aquest gènere només es va trobar en una abundància relativa entre 0.01-0.07%, el qual explica la seua baixa tassa de recuperació a partir de mostres ambientals. En resum, els resultats d'aquesta tesi poden ser d'utilitat per als programes de control d'aquest patogen duts a terme per les autoritats de salut pública, ja que proporcionen una nova percepció de la seua epidemiologia molecular, amb aplicació immediata a la vigilància i la investigació de brots., Sánchez Busó, L. (2015). Genetic and genomic variability of Legionella pneumophila: applications to molecular epidemiology and public health [Tesis doctoral no publicada]. Universitat Politècnica de València. doi:10.4995/Thesis/10251/52854., TESIS