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Foodborne diseases represent a link between environmental, animal, and human health interfaces from the One Health perspective. Whole genome sequencing (WGS) is becoming the gold standard in foodborne surveillance, worldwide. WGS than provides precision data from pathogens allows laboratories to resolve the genetic relations among all sources from One Health perspective, especially during outbreak investigations, getting insights into their transmission routes and pathogenicity.Salmonellaspp. is the most prevalent foodborne bacteria in Colombia, in 2020, 268 foodborne outbreaks were reported to National health institute (INS) and 3079 invasive and faecal salmonellosis samples from 81% of the Colombian geographical regions. Several studies in different food sources exhibited an increase of contamination withSalmonella, a public health concern due to the steady development of antimicrobial resistance associated to specific serovars. However, integration ofSalmonella spp. data including food-chain supply and clinical interfaces is very scarce in Colombia. This study carried out a national comparison ofSalmonellaisolates collected from food-chain supply and clinical sources. Using an epidemiological and phenotypic approach, we demonstrated the higher resolution of WGS compared with PFGE, routinely used inSalmonellasurveillance in Colombia. For example, the resolution of PFGE allowed the description of two main clusters of foodSalmonellaEnteritidis isolates which were expanded to eight clades by using WGS. Virulence factors and antimicrobial determinant genes observed in the foodborne clades should be considered a public health concern in Colombia. WGS is a technology that provides precise and valid evidence for the establishment of dissemination routes of foodborne high-riskSalmonellaclades, but it requires an integrative and continued collaboration between the stakeholders across the One Health interfaces to promote and support integrated real-time actions in public health.

BackgroundAcinetobacter baumanniicause difficult-to-treat infections mostly among immunocompromised patients. Clinically relevantA. baumanniilineages and their carbapenem resistance mechanisms are sparsely described in Nigeria.ObjectiveThis study aimed to characterise the diversity and genetic mechanisms of carbapenem resistance amongA. baumanniistrains isolated from hospitals in southwestern Nigeria.MethodsWe sequenced the genomes of allA. baumanniiisolates submitted to Nigeria’s antimicrobial resistance surveillance reference laboratory between 2016 – 2020 on an Illumina platform and performedin silicogenomic characterisation. Selected strains were sequenced using the Oxford Nanopore technology to characterise the genetic context of carbapenem resistance genes.ResultsThe 86A. baumanniiisolates were phylogenetically diverse and belonged to 35 distinct sequence types (STs), 16 of which were novel. Thirty-eight (44.2%) isolates belonged to none of the known international clones (ICs). Over 50% of the isolates were phenotypically resistant to 10 of 12 tested antimicrobials. Majority (n=54) of the isolates were carbapenem-resistant, particularly the IC7 (100%) and IC9 (>91.7%) strains.blaOXA-23(34.9%) andblaNDM-1(27.9%) were the most common carbapenem resistance genes detected. AllblaOXA-23genes were carried on Tn2006or Tn2006-like transposons. Our findings suggest that the mobilisation of a 10kb Tn125composite transposon is the primary means ofblaNDM-1dissemination.ConclusionOur findings highlight an increase inblaNDM-1prevalence and the widespread transposon-facilitated dissemination of carbapenemase genes in diverseA. baumanniilineages in southwestern Nigeria. We make the case for improving surveillance of these pathogens in Nigeria and other understudied settings.ImportanceAcinetobacter baumannii are increasingly clinically relevant due to their propensity to harbour genes conferring resistance to multiple antimicrobials, as well as their ability to persist and disseminate in hospital environments and cause difficult-to-treat nosocomial infections. Little is known about the molecular epidemiology and antimicrobial resistance profiles of these organisms in Nigeria, largely due to limited capacity for their isolation, identification, and antimicrobial susceptibility testing. Our study characterised the diversity and antimicrobial resistance profiles of clinical A. baumannii in southwestern Nigeria using whole-genome sequencing. We also identified the key genetic elements facilitating the dissemination of carbapenem resistance genes within this species. This study provides key insights into the clinical burden and population dynamics of A. baumannii in hospitals in Nigeria and highlights the importance of routine whole-genome sequencing-based surveillance of this and other previously understudied pathogens in Nigeria and other similar settings.

BackgroundKlebsiella pneumoniae is a World Health Organization high-priority antibiotic-resistant pathogen. However, little is known about Klebsiella lineages circulating in Nigeria.MethodsWe performed whole-genome sequencing (WGS) of 141 Klebsiella isolated between 2016 and 2018 from clinical specimens at 3 antimicrobial-resistance (AMR) sentinel surveillance tertiary hospitals in southwestern Nigeria. We conducted in silico multilocus sequence typing; AMR gene, virulence gene, plasmid, and K and O loci profiling; as well as phylogenetic analyses, using publicly available tools and Nextflow pipelines.ResultsPhylogenetic analysis revealed that the majority of the 134 K. pneumoniae and 5 K. quasipneumoniae isolates from Nigeria characterized are closely related to globally disseminated multidrug-resistant clones. Of the 39 K. pneumoniae sequence types (STs) identified, the most common were ST307 (15%), ST5241 (12%), ST15 (~9%), and ST25 (~6%). ST5241, 1 of 10 novel STs detected, is a single locus variant of ST636 carrying dfrA14, tetD, qnrS, and oqxAB resistance genes. The extended-spectrum β-lactamase (ESBL) gene blaCTX_M-15 was seen in 72% of K. pneumoniae genomes, while 8% encoded a carbapenemase. No isolate carried a combination of carbapenemase-producing genes. Four likely outbreak clusters from 1 facility, within STs 17, 25, 307, and 5241, were ESBL but not carbapenemase-bearing clones.ConclusionsThis study uncovered known and novel K. pneumoniae lineages circulating in 3 hospitals in Southwest Nigeria that include multidrug-resistant ESBL producers. Carbapenemase-producing isolates remain uncommon. WGS retrospectively identified outbreak clusters, pointing to the value of genomic approaches in AMR surveillance for improving infection prevention and control in Nigerian hospitals.

Staphylococcus aureusremains one of the leading causes of infections worldwide and a common cause of bacteremia. However, studies documenting the epidemiology ofS. aureusin South America (SA) using genomics are scarce. We hereby report on the largest to date genomic epidemiology study of both methicillin-resistantS. aureus(MRSA) and methicillin-susceptibleS. aureus(MSSA) in SA, conducted by the StaphNET-SA network. We characterised 404 genomes recovered from a prospective observational study ofS. aureusbacteremia in 58 hospitals from Argentina, Bolivia, Brazil, Paraguay and Uruguay between April and October 2019.We show that a minority ofS. aureusisolates are phenotypically multi-drug resistant (5.2%), but more than a quarter are resistant to macrolide-lincosamide-streptogramin B (MLSb). MSSA were more genetically diverse than MRSA. Lower rates of associated antimicrobial resistance in CA-MRSA vs HA-MRSA were found in association with threeS. aureusgenotypes dominating the MRSA population: CC30-MRSA-IVc-t019-lukS/F-PV+, CC5-MRSA-IV-t002-lukS/F-PV-, and CC8-MRSA-IVc-t008-lukS/F-PV+-COMER+. These are historically from a CA origin, carry on average less AMR determinants, and often lack key virulence genes.Surprisingly, CC398-MSSA-t1451-lukS/F-PV-related to the CC398 human-associated lineage is widely disseminated throughout the region, and is described here for the first time as the most prevalent MSSA lineage in SA. Moreover, CC398 strains carryingermTandsh_fabI(related to triclosan resistance) were recovered from both CA and HA origin, and are largely responsible for the MLSb rates of MSSA strains (inducible iMLSb phenotype).The frequency of MRSA and MSSA lineages differed between countries but the most prevalentS. aureusgenotypes are high-risk clones widespread in the South American region without clear country-specific phylogeographic structure. Therefore our findings underscore the need for continuous genomic surveillance by regional networks such as StaphNET-SA.Impact statementS. aureusis a common cause of bacteremia, a serious life threatening disease, and the second leading pathogen for deaths associated with resistance in 2019. However, genomic surveillance ofS. aureuscausing invasive infections in South America is limited. Previous surveillance studies have focused on the dissemination of MRSA with increasing AMR and/or virulence, but have not characterised MSSA in detail.Here, we show the results of a prospective observational study of genomic surveillance ofS. aureuscausing bacteremia conducted in South America during 2019 by the StaphNET-SA network.Our study reveals that in 2019 most bloodstream infections were caused by successful MRSA lineages of community origin, generally not MDR, and lacking key virulence genes in some cases. Importantly, we also describe here for the first time CC398-MSSA-t1451as the most prevalent and widely disseminated MSSA clone causing bacteraemia in the region during 2019. This human adapted clone, present both in the community and hospital environment, carries a gene conferring resistance against an antiseptic widely used in our region, and is largely responsible for the increasing resistance rates to erythromycin and clindamycin observed in MSSA.We also show evidence of readily transmission of the most prevalent MRSA and MSSA high-risk clones across country borders, which highlights the need for continuous genomic surveillance by regional networks such as StaphNET-SA.Data SummaryAll supporting data, code and protocols have been provided within the article or through supplementary data files. Five supplementary figures and five supplementary tables are available with the online version of this article.Sequence read files for all samples used in this study have been deposited in the European Nucleotide Archive under the project accession number PRJEB37318. Individual accession numbers for each sample are also detailed in microreact_project:https://microreact.org/project/staphnet-sa-1st-survey. Genome assemblies are available via Pathogenwatchhttps://pathogen.watch/collection/jz7rcy1zv0sk-staphnet-sa-first-survey.

Escherichia coli bloodstream infections are typically attributed to a limited number of lineages that carry virulence factors associated with invasiveness. In Nigeria, the identity of circulating clones is largely unknown and surveillance of their antimicrobial resistance has been limited. We verified and whole-genome sequenced 68 2016–2018 bloodstream E. coli isolates from three sentinel sites in South-Western Nigeria and susceptibility tested 67 of them. Resistance to antimicrobials commonly used in Nigeria was high, with 67 (100 %), 62 (92.5 %), 53 (79.1 %) and 37 (55.2 %) showing resistance to trimethoprim, ampicillin, ciprofloxacin and aminoglycosides, respectively. Thirty-five (51 %) isolates carried extended-spectrum β-lactamase genes and 32 (91 %) of these were multidrug resistant. All the isolates were susceptible to carbapenems and colistin. The strain set included globally disseminated high-risk clones from sequence type (ST)12 (2), ST131 (12) and ST648 (4). Twenty-three (33.8 %) of the isolates clustered within two clades. The first of these consisted of ST131 strains, comprising O16:H5 and O25:H4 sub-lineages. The second was an ST10–ST167 complex clade comprising strains carrying O-antigen and capsular genes of likely Klebsiella origin, identical to those of avian pathogenic E. coli Sanji, and serotyped in silico as O89, O101 or ONovel32, depending on the tool used. Four temporally associated ST90 strains from one sentinel were closely related enough to suggest that at least some of them represented a retrospectively detected outbreak cluster. Our data implicate a broad repertoire of E. coli isolates associated with bloodstream infections in South-West Nigeria. Continued genomic surveillance is valuable for tracking clones of importance and for outbreak identification.

Increasing antimicrobial resistance (AMR) in Salmonella has been observed in the Philippines. This study aims to utilize whole genome sequencing (WGS) to characterize the population and AMR mechanisms of Salmonella captured by the Philippine Antimicrobial Resistance Surveillance Program (ARSP) and contrast to traditional laboratory methods.We sequenced the whole genomes of 148 Salmonella Typhi (S. Typhi) and 65 non-typhoidal Salmonella (NTS) collected in the Philippines in 2013–2014. From the genome sequences, we determined the serotype, multilocus sequence type, presence of determinants of antimicrobial resistance and relatedness between isolates. We also compared the genotypic predictions of serotype and AMR to the phenotypic data.AMR rates in S. Typhi were low, with sparse acquisition of mutations associated with reduced susceptibility to fluoroquinolones or extended-spectrum beta-lactamases (ESBL) genes. In contrast, three quarters of NTS isolates were insusceptible to at least one antimicrobial, with more than half carrying mutations and/or genes linked to resistance to fluoroquinolones. ESBL genes were detected in five genomes that also carried other AMR determinants. The population of S. Typhi was dominated by the likely endemic genotype 3.0, which also caused of a putative local outbreak susceptible to antibiotics. The main NTS clades were global epidemic S. Enteritidis ST11 and the monophasic variant of S. Typhimurium (I 4,[5],12:i:-) ST34, which had frequently been serotyped as S. Typhimurium in the laboratory.This was the first time that Salmonella isolated from the Philippines were characterized by WGS and we provide evidence of its utility for ongoing surveillance at the ARSP.

Background Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an emerging public health problem. This study explores the specifics of CRKP epidemiology in Colombia based on whole genome sequencing (WGS) of the National Reference Laboratory at Instituto Nacional de Salud (INS)’s 2013–2017 sample collection. Methods A total of 425 CRKP isolates from 21 departments were analyzed by HiSeq-X10®Illumina high-throughput sequencing. Bioinformatic analysis was performed, primarily using the pipelines developed collaboratively by the National Institute for Health Research Global Health Research Unit (GHRU) on Genomic Surveillance of Antimicrobial Resistance (AMR), and AGROSAVIA. Results Of the 425 CRKP isolates, 91.5% were carbapenemase-producing strains. The data support a recent expansion and the endemicity of CRKP in Colombia with the circulation of 7 high-risk clones, the most frequent being CG258 (48.39% of isolates). We identified genes encoding carbapenemases blaKPC-3, blaKPC-2, blaNDM-1, blaNDM-9, blaVIM-2, blaVIM-4, and blaVIM-24, and various mobile genetic elements (MGE). The virulence of CRKP isolates was low, but colibactin (clb3) was present in 25.2% of isolates, and a hypervirulent CRKP clone (CG380) was reported for the first time in Colombia. ST258, ST512, and ST4851 were characterized by low levels of diversity in the core genome (ANI > 99.9%). Conclusions The study outlines complex CRKP epidemiology in Colombia. CG258 expanded clonally and carries specific carbapenemases in specific MGEs, while the other high-risk clones (CG147, CG307, and CG152) present a more diverse complement of carbapenemases. The specifics of the Colombian situation stress the importance of WGS-based surveillance to monitor evolutionary trends of sequence types (STs), MGE, and resistance and virulence genes.

BackgroundKlebsiella pneumoniae is a critically important pathogen in the Philippines. Isolates are commonly resistant to at least two classes of antibiotics, yet mechanisms and spread of its resistance are not well studied.MethodsA retrospective sequencing survey was performed on carbapenem-, extended spectrum beta-lactam- and cephalosporin-resistant Klebsiella pneumoniae isolated at 20 antimicrobial resistance (AMR) surveillance sentinel sites from 2015-2017. We characterized 259 isolates using biochemical methods, antimicrobial susceptibility testing, and whole genome sequencing (WGS). Known AMR mechanisms were identified. Potential outbreaks were investigated by detecting clusters from epidemiologic, phenotypic and genome-derived data.ResultsPrevalent AMR mechanisms detected include blaCTX-M-15 (76.8%) and blaNDM-1 (37.5%). An epidemic IncFII(Yp) plasmid carrying blaNDM-1 was also detected in 46 isolates from 6 sentinel sites and 14 different sequence types (ST). This plasmid was also identified as the main vehicle of carbapenem resistance in 2 previously unrecognized local outbreaks of ST348 and ST283 at 2 different sentinel sites. A third local outbreak of ST397 was also identified but without the IncFII(Yp) plasmid. Isolates in each outbreak site showed identical STs, K- and O-loci, and similar resistance profiles and AMR genes. All outbreak isolates were collected from blood of children aged ConclusionWGS provided an in-depth understanding of the epidemiology of AMR in the Philippines, which was not possible with only phenotypic and epidemiologic data. The identification of three previously unrecognized Klebsiella outbreaks highlights the utility of WGS in outbreak detection, as well as its importance in public health and in implementing infection control programs.summaryWhole genome sequencing identified three distinct previously unrecognized local outbreaks in a retrospective study in the Philippines, along with an epidemic plasmid carrying antimicrobial resistance genes, highlighting its importance in antimicrobial resistance surveillance, outbreak detection and infection control.

Performing whole genome sequencing (WGS) for the surveillance of antimicrobial resistance offers the ability to determine not only the antimicrobials to which rates of resistance are increasing, but also the evolutionary mechanisms and transmission routes responsible for the increase at local, national, and global scales. To derive WGS-based outputs, a series of processes are required, beginning with sample and metadata collection, followed by nucleic acid extraction, library preparation, sequencing, and analysis. Throughout this pathway there are many data-related operations required (informatics) combined with more biologically focused procedures (bioinformatics). For a laboratory aiming to implement pathogen genomics, the informatics and bioinformatics activities can be a barrier to starting on the journey; for a laboratory that has already started, these activities may become overwhelming. Here we describe these data bottlenecks and how they have been addressed in laboratories in India, Colombia, Nigeria, and the Philippines, as part of the National Institute for Health Research Global Health Research Unit on Genomic Surveillance of Antimicrobial Resistance. The approaches taken include the use of reproducible data parsing pipelines and genome sequence analysis workflows, using technologies such as Data-flo, the Nextflow workflow manager, and containerization of software dependencies. By overcoming barriers to WGS implementation in countries where genome sampling for some species may be underrepresented, a body of evidence can be built to determine the concordance of antimicrobial sensitivity testing and genome-derived resistance, and novel high-risk clones and unknown mechanisms of resistance can be discovered.

Antimicrobial resistance (AMR) is considered a global threat, and novel drug discovery needs to be complemented with systematic and standardized epidemiological surveillance. Surveillance data are currently generated using phenotypic characterization. However, due to poor scalability, this approach does little for true epidemiological investigations. There is a strong case for whole-genome sequencing (WGS) to enhance the phenotypic data. To establish global AMR surveillance using WGS, we developed a laboratory implementation approach that we applied within the NIHR Global Health Research Unit (GHRU) on Genomic Surveillance of Antimicrobial Resistance. In this paper, we outline the laboratory implementation at 4 units: Colombia, India, Nigeria, and the Philippines. The journey to embedding WGS capacity was split into 4 phases: Assessment, Assembly, Optimization, and Reassessment. We show that on-boarding WGS capabilities can greatly enhance the real-time processing power within regional and national AMR surveillance initiatives, despite the high initial investment in laboratory infrastructure and maintenance. Countries looking to introduce WGS as a surveillance tool could begin by sequencing select Global Antimicrobial Resistance Surveillance System (GLASS) priority pathogens that can demonstrate the standardization and impact genome sequencing has in tackling AMR.

The administration and governance of grant funding across global health organizations presents enormous challenges. Meeting these challenges is crucial to ensuring that funds are used in the most effective way to improve health outcomes, in line with the United Nations’ Sustainable Development Goal 3, “Ensure healthy lives and promote well-being for all at all ages.” The Good Financial Grant Practice (GFGP) Standard (ARS 1651) is the world’s first and, currently, only international standard for the financial governance and management of grant funding. Through consensus building and global harmonization between both low- and middle-income and high-income country players, the GFGP Standard has achieved a leveling impact: GFGP applies equally to, and can be implemented by, all types of organization, regardless of location, size, or whether they predominantly give or receive funding.GFGP can be used as a tool for addressing some of the challenges of the current funding model. Here, we describe our experiences and lessons learned from implementing GFGP across 4 diverse research institutions in India, Nigeria, Colombia, and the Philippines as part of our National Institute for Health Research Global Health Research Unit on Genomic Surveillance of Antimicrobial Resistance.

BackgroundS. aureus is a major pathogen in India, causing nosocomial infections, but little is known about its molecular epidemiology and mechanisms of resistance in hospital settings. Here, we use WGS to characterize 508 S. aureus clinical isolates collected across India and analyze them in a global context.MethodsWhole-genome sequencing was performed on 508 clinical isolates of S. aureus collected from 17 sentinel sites across India between 2014 and 2019 with the Illumina platform. AMR genotypes were predicted using Staphopia. Isolates carrying novel SCCmec cassettes were further characterized using long-read sequencing. A temporal analysis of clonal complex (CC) 22 global isolates from 14 different studies was performed using BactDating.ResultsSequencing results confirmed 478 isolates as S. aureus. ST22, ST772 & ST239 were the major clones identified. An in-depth analysis of the 175 CC22 Indian isolates identifies two novel ST22 MRSA clones, PVL+ and one harboring the tsst-1 gene. Temporal analysis showed that these two ST22 clusters shared a common ancestor in the 1980s and they became widespread after the year 2000 in India. Analyzing these in a global context, we found evidence of transmission of the two Indian clones to other parts of the world.ConclusionOur study describes a large retrospective S. aureus sampled from India. By comparing the Indian isolates globally we show the evidence of the international transmission of ST22 Indian isolates. Even though the two of the major dominant clones (ST772 and ST239) using WGS have been reported, this is the first study that describes the third dominant clone (ST22) in India.Impact statementStaphylococcus aureus is an opportunistic pathogen listed as a high-priority pathogen by WHO. It is a leading cause of nosocomial infections in India and worldwide. Our study is the first study to describe the epidemiology of S. aureus in India with a large sample set of 478. Here we describe a collection of 478 S. aureus genomes, isolated from 17 sentinel sites in India, between 2014 and 2019. With the focus on understanding sequence types, AMR profiles, SCCmec types, and spa types and discuss these in the context of previous molecular studies on S. aureus conducted in India. We also conducted an in-depth analysis of the Clonal Complex 22 Indian isolates and we identified two novel ST22 MRSA clones, both PVL+ and one harboring the tsst-1 gene. Temporal analysis shows that these two ST22 clusters originated around 2010 in India. Analyzing these in a global context, we found evidence of transmission of the two Indian clones in other parts of the world. Analysis of a cluster of 33 isolates belonging to ST239 from a single hospital in Bangalore indicates an outbreak that persisted over the period of three years from a single contamination source. The novel SCCmec types identified in our study are characterized using long reads to understand their genetic structure.Data SummaryIllumina read files of the strains used in the study have been deposited in European Nucleotide Archive, BioProject PRJEB29740 (https://www.ebi.ac.uk/ena/browser/view/PRJEB29740?show=reads). A full list of accession numbers for all sequence read files is provided in Supplementary table 2.Nanopore reads are submitted to ENA under the BioProject PRJEB50484.Metadata and other related information on the strains are provided in the microreact project with different views in this link microreact.org/s.aureus_ghru_analysis.Strain information for the ST22 samples used from other studies is provided in microreact at this link: https://microreact.org/project/2xDvKQhriNveJ4kiVYsmSQ-s-aureus-wgs-study.The authors confirm all supporting data, code and protocols have been provided within the article or the supporting data repository.

In this Supplement, we detail outputs of the National Institute for Health Research Global Health Research Unit on Genomic Surveillance of Antimicrobial Resistance project, covering practical implementation of whole-genome sequencing across our consortium, which consists of laboratories in Colombia, India, Nigeria, and the Philippines.

This work was supported by a Newton Fund award from the Medical Research Council (United Kingdom) MR/N019296/1 and the Philippine Council for Health Research and Development. Additional support provided by National Institute for Health Research (UK) Global Health Research Unit on genomic Surveillance of AMR (16/136/111) and by research grant U01CA207167 from the U.S. National Institutes of Health. Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the leading causes of both nosocomial and community infections worldwide. In the Philippines, MRSA rates have remained above 50% since 2010, but resistance to other antibiotics, including vancomycin, is low. The MRSA burden can be partially attributed to pathogen-specific characteristics of the circulating clones, but little was known about the S. aureus clones circulating in the Philippines. We sequenced the whole genomes of 116 S. aureus isolates collected in 2013-2014 within the Antimicrobial Resistance Surveillance Program. The multilocus sequence type, spa type, SCCmec type, presence of antimicrobial resistance (AMR) determinants and virulence genes and relatedness between the isolates were all derived from the sequence data. The concordance between phenotypic and genotypic resistance was also determined. The MRSA population in the Philippines comprised a limited number of genetic clones, including several international epidemic clones, such as CC30-spa-t019-SCCmec-IV-PVL+, CC5-SCCmec-typeIV and ST239-spa-t030-SCCmec-typeIII. The CC30 genomes were related to the South-West Pacific clone but formed a distinct, diverse lineage, with evidence of global dissemination. We showed independent acquisition of resistance to sulfamethoxazole/trimethoprim in various locations and genetic clones but mostly in paediatric patients with invasive infections. The concordance between phenotypic and genotypic resistance was 99.68% overall for eight antibiotics in seven classes. We have made the first comprehensive genomic survey of S. aureus in the Philippines, which bridges the gap in genomic data from the Western Pacific Region and will constitute the genetic background for contextualizing prospective surveillance. Publisher PDF

We sequenced the whole genomes of 117Carbapenem resistance was mainly explained by acquisition of the class-D β-lactamase gene blaThis is the first extensive genomic study of carbapenem-resistant

We report the persistent circulation of third-generation cephalosporin resistant Salmonella Typhi in Mumbai, linked to the acquisition and maintenance of a previously characterized IncX3 plasmid carrying the ESBL gene blaSHV-12 and the fluoroquinolone resistance gene qnrB7 in the genetic context of a triple mutant also associated with fluoroquinolone resistance.

Performing whole genome sequencing (WGS) for the surveillance of antimicrobial resistance (AMR) offers the ability to determine not only the antimicrobials to which rates of resistance are increasing, but also the evolutionary mechanisms and transmission routes responsible for the increase at local, national, and global scales. To derive WGS-based outputs, a series of processes are required, beginning with sample and metadata collection, followed by nucleic acid extraction, library preparation, sequencing, and analysis. Throughout this pathway there are many data-related operations required (informatics) combined with more biologically-focused procedures (bioinformatics). For a laboratory aiming to implement pathogen genomics, the informatics and bioinformatics activities can be a barrier to starting on the journey; for a laboratory that has already started, these activities may become overwhelming. Here we describe these data bottlenecks and how they have been addressed in laboratories in India, Colombia, Nigeria, and the Philippines, as part of the NIHR Global Health Research Unit on Genomic Surveillance of AMR. The approaches taken include the use of reproducible data parsing pipelines and genome sequence analysis workflows, using technologies such as Data-flo, the Nextflow workflow manager, and containerization of software dependencies. By overcoming barriers to WGS implementation in countries where genome sampling for some species may be underrepresented, a body of evidence can be built to determine the concordance of antimicrobial sensitivity testing (AST) and genome-derived resistance, novel high-risk clones can be discovered, and unknown mechanisms of resistance discovered.

BackgroundKlebsiella species, including the notable pathogen K. pneumoniae, are increasingly associated with antimicrobial resistance (AMR). Genome-based surveillance can inform interventions aimed at controlling AMR. However, its widespread implementation requires tools to streamline bioinformatic analyses and public health reporting.MethodsWe developed the web application Pathogenwatch, which implements analytics tailored to Klebsiella species for integration and visualization of genomic and epidemiological data. We populated Pathogenwatch with 16,537 public Klebsiella genomes to enable contextualization of user genomes. We demonstrated its features with 1,636 genomes from four low- and middle-income countries (LMICs) participating in the NIHR Global Health Research Unit (GHRU) on AMR.ResultsUsing Pathogenwatch, we found that GHRU genomes were dominated by a small number of epidemic drug-resistant clones of K. pneumoniae. However, differences in their distribution were observed (e.g. ST258/512 dominated in Colombia, ST231 in India, ST307 in Nigeria, ST147 in the Philippines). Phylogenetic analyses including public genomes for contextualization enabled retrospective monitoring of their spread. In particular, we identified hospital outbreaks, detected introductions from abroad, and uncovered clonal expansions associated with resistance and virulence genes. Assessment of loci encoding O-antigens and capsule in K. pneumoniae, which represent possible vaccine candidates, showed that three O-types (O1-O3) represented 88.9% of all genomes, whereas capsule types were much more diverse.ConclusionsPathogenwatch provides a free, accessible platform for real-time analysis of Klebsiella genomes to aid surveillance at local, national and global levels. We have improved representation of genomes from GHRU participant countries, further facilitating ongoing surveillance.40-word summaryPathogenwatch is a free web-application for analysis of Klebsiella genomes to aid surveillance at local, national and global levels. We improved the representation of genomes from middle-income countries through the Global Health Research Unit on AMR, further facilitating ongoing surveillance.FUNDINGThis work was supported by Official Development Assistance (ODA) funding from the National Institute of Health Research [grant number 16_136_111].This research was commissioned by the National Institute of Health Research using Official Development Assistance (ODA) funding. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health.CONFLICT OF INTERESTThe authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest.

Background Antimicrobial-resistant (AMR) Neisseria gonorrhoeae is an urgent threat to public health, as strains resistant to at least one of the two last-line antibiotics used in empiric therapy of gonorrhoea, ceftriaxone and azithromycin, have spread internationally. Whole genome sequencing (WGS) data can be used to identify new AMR clones and transmission networks and inform the development of point-of-care tests for antimicrobial susceptibility, novel antimicrobials and vaccines. Community-driven tools that provide an easy access to and analysis of genomic and epidemiological data is the way forward for public health surveillance. Methods Here we present a public health-focussed scheme for genomic epidemiology of N. gonorrhoeae at Pathogenwatch (https://pathogen.watch/ngonorrhoeae). An international advisory group of experts in epidemiology, public health, genetics and genomics of N. gonorrhoeae was convened to inform on the utility of current and future analytics in the platform. We implement backwards compatibility with MLST, NG-MAST and NG-STAR typing schemes as well as an exhaustive library of genetic AMR determinants linked to a genotypic prediction of resistance to eight antibiotics. A collection of over 12,000 N. gonorrhoeae genome sequences from public archives has been quality-checked, assembled and made public together with available metadata for contextualization. Results AMR prediction from genome data revealed specificity values over 99% for azithromycin, ciprofloxacin and ceftriaxone and sensitivity values around 99% for benzylpenicillin and tetracycline. A case study using the Pathogenwatch collection of N. gonorrhoeae public genomes showed the global expansion of an azithromycin-resistant lineage carrying a mosaic mtr over at least the last 10 years, emphasising the power of Pathogenwatch to explore and evaluate genomic epidemiology questions of public health concern. Conclusions The N. gonorrhoeae scheme in Pathogenwatch provides customised bioinformatic pipelines guided by expert opinion that can be adapted to public health agencies and departments with little expertise in bioinformatics and lower-resourced settings with internet connection but limited computational infrastructure. The advisory group will assess and identify ongoing public health needs in the field of gonorrhoea, particularly regarding gonococcal AMR, in order to further enhance utility with modified or new analytic methods.

Staphylococcus aureus clonal complex 30 (CC30) has given rise to epidemics worldwide and is one of the most prevalent lineages in Argentina, represented by sequence type 30 methicillin-resistant S. aureus SCCmec type IV (ST30-MRSA-IV). ST30-MRSA-IV has displaced previous prevalent clones in the country and demonstrated increased virulence. Despite the burden of infections caused by ST30-MRSA-IV both in hospitals and in communities in Argentina, no detailed genome-based characterization of this clone is available to date. In this study, we used whole-genome sequencing (WGS) to evaluate the genetic diversity, population structure, and genomic characteristics of 190 CC30-MRSA strains circulating in Argentina between 2004 and 2015. Phylogenetic analysis revealed the existence of 4 major clades: ARG-1 (CC30-MRSA-IVc-spa t012), ARG-2 (ST30-MRSA-IVc-spa t021 related), ARG-3 (ST30-MRSA-IVh/j-spa t021 and related), and ARG-4 (CC30-MRSA-IVc-spa t019 and related). The clades were characterized by different distributions of antimicrobial resistance determinants, virulence genes, and mobile genetic elements (MGEs). While ARG-1 and ARG-4 were related to global epidemic MRSA-16 (EMRSA-16) and South West Pacific (SWP) clones, respectively, ARG-3 was phylogenetically distinct from previously defined CC30 epidemic clones. ARG-4, the most prevalent and geographically disseminated in the collection (N = 164), was characterized by specific MGEs and chromosomal mutations that might have contributed to its virulence and success. To our knowledge, this is the first genomic epidemiology study of CC30-MRSA in Argentina, which will serve as baseline genomic data going forward to inform public health measures for infection prevention and control. IMPORTANCE The rise in prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is of public health concern. In Argentina, several studies documented a shift in the epidemiology of CA-MRSA since 2009, with clonal complex 30 (CC30) and, in particular, sequence type 30 MRSA SCCmec type IV (ST30-MRSA-IV) replacing other clones both in communities and in hospitals and possibly displaying increased virulence. By sequencing the whole genomes of 190 CC30 MRSA isolates recovered from Argentina between 2005 and 2015, we showed that they represented a diverse population composed of 4 major clades. The predominant clade evolved from the South West Pacific clone but has acquired a distinct repertoire of mobile genetic elements, virulence genes, and chromosomal mutations that might play a role in its success. Our work is the first extensive genomic study of CC30 S. aureus in Argentina and will contribute not only to the development of genomic surveillance in the region but also to our understanding of the global epidemiology of this pathogen.

As whole-genome sequencing capacity becomes increasingly decentralized, there is a growing opportunity for collaboration and the sharing of surveillance data within and between countries to inform typhoid control policies. This vision requires free, community-driven tools that facilitate access to genomic data for public health on a global scale. Here we present the Pathogenwatch scheme for Salmonella enterica serovar Typhi (S. Typhi), a web application enabling the rapid identification of genomic markers of antimicrobial resistance (AMR) and contextualization with public genomic data. We show that the clustering of S. Typhi genomes in Pathogenwatch is comparable to established bioinformatics methods, and that genomic predictions of AMR are highly concordant with phenotypic susceptibility data. We demonstrate the public health utility of Pathogenwatch with examples selected from >4,300 public genomes available in the application. Pathogenwatch provides an intuitive entry point to monitor of the emergence and spread of S. Typhi high risk clones., Whole genome sequencing data are increasingly becoming routinely available but generating actionable insights is challenging. Here, the authors describe Pathogenwatch, a web tool for genomic surveillance of S. Typhi, and demonstrate its use for antimicrobial resistance assignment and strain risk assessment.

This work was supported by a Newton Fund award from the Medical Research Council (United Kingdom) MR/N019296/1 and the Philippine Council for Health Research and Development. Additional support was provided by the National Institute for Health Research (United Kingdom), the Global Health Research Unit on genomic surveillance of AMR (16/136/111) and by research grant U01CA207167 from the US National Institutes of Health. Antimicrobial-resistant Neisseria gonorrhoeae is a major threat to public health and is of particular concern in the Western Pacific Region, where the incidence of gonorrhoea is high. The Antimicrobial Resistance Surveillance Program (ARSP) has been capturing information on resistant gonorrhoea since 1996, but genomic epidemiology studies on this pathogen are lacking in the Philippines. We sequenced the whole genomes of 21 N. gonorrhoeae isolates collected in 2013-2014 by ARSP. The multilocus sequence type, multiantigen sequence type, presence of determinants of antimicrobial resistance and relatedness among the isolates were all derived from the sequence data. The concordance between phenotypic and genotypic resistance was also determined. Ten of 21 isolates were resistant to penicillin, ciprofloxacin and tetracycline, due mainly to the presence of the blaTEM gene, the S91F mutation in the gyrA gene and the tetM gene, respectively. None of the isolates was resistant to ceftriaxone or cefixime. The concordance between phenotypic and genotypic resistance was 92.38% overall for five antibiotics in four classes. Despite the small number of isolates studied, they were genetically diverse, as shown by the sequence types, the N. gonorrhoeae multiantigen sequence typing types and the tree. Comparison with global genomes placed the Philippine genomes within global lineage A and led to the identification of an international transmission route. This first genomic survey of N. gonorrhoeae isolates collected by ARSP will be used to contextualize prospective surveillance. It highlights the importance of genomic surveillance in the Western Pacific and other endemic regions for understanding the spread of drug-resistant gonorrhoea worldwide. Publisher PDF

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.

National networks of laboratory-based surveillance of antimicrobial resistance (AMR) monitor resistance trends and disseminate these data to AMR stakeholders. Whole-genome sequencing (WGS) can support surveillance by pinpointing resistance mechanisms and uncovering transmission patterns. However, genomic surveillance is rare in low- and middle-income countries. Here, we implement WGS within the established Antimicrobial Resistance Surveillance Program of the Philippines via a binational collaboration. In parallel, we characterize bacterial populations of key bug-drug combinations via a retrospective sequencing survey. By linking the resistance phenotypes to genomic data, we reveal the interplay of genetic lineages (strains), AMR mechanisms, and AMR vehicles underlying the expansion of specific resistance phenotypes that coincide with the growing carbapenem resistance rates observed since 2010. Our results enhance our understanding of the drivers of carbapenem resistance in the Philippines, while also serving as the genetic background to contextualize ongoing local prospective surveillance., Whole-genome sequencing (WGS) can support drug resistance surveillance, but is rare in low- and middle-income countries. Here, the authors integrate WGS within the national antimicrobial resistance surveillance program in the Philippines and conduct a retrospective sequencing survey to characterize bacterial populations and dissect resistance phenotypes.

Methicillin Resistant Staphylococcus aureus (MRSA) remains one of the leading causes of both nosocomial and community infections worldwide. In the Philippines, MRSA rates have remained above 50% since 2010, but resistance to other antibiotics, including vancomycin, is low. The MRSA burden can be partially attributed to pathogen-specific characteristics of the circulating clones, but little was known about the S. aureus circulating clones in the Philippines.We sequenced the whole genomes of 116 S. aureus isolates collected in 2013-2014 by the Antimicrobial Resistance Surveillance Program. The multi-locus sequence type, spa type, SCC-mec type, presence of antimicrobial resistance (AMR) determinants and virulence genes, and relatedness between the isolates were all derived from the sequence data. The concordance between phenotypic and genotypic resistance was also determined.The MRSA population in the Philippines was composed of a limited number of genetic clones, including several international epidemic clones, such as CC30-spa-t019-SCCmec-IV-PVL+, CC5-SCCmec-typeIV, and ST239-spa-t030-SCCmec-typeIII. The CC30 genomes were related to the South West Pacific clone, but formed a distinct and diverse lineage, with evidence of global dissemination. We showed the independent acquisition of resistance to sulfamethoxazole/trimethoprim across different locations and genetic clones, but mostly in pediatric patients with invasive infections. The concordance between phenotypic and genotypic resistance was 99.68% overall for 8 antibiotics in 7 classes.We produced the first comprehensive genomic survey of S. aureus in the Philippines, which bridges the gap in genomic data from the Western Pacific region and will constitute the genetic background to contextualize ongoing prospective surveillance.

Pseudomonas aeruginosa is an opportunistic pathogen often causing nosocomial infections that are resilient to treatment due to an extensive repertoire of intrinsic and acquired resistance mechanisms. In recent years, increasing resistance rates to antibiotics such as carbapenems and extended-spectrum cephalosporins have been reported, as well as multi-drug resistant and possible extremely drug-resistant rates of approximately 21% and 15%, respectively. However, the molecular epidemiology and AMR mechanisms of this pathogen remains largely uncharacterized.We sequenced the whole genomes of 176 P. aeruginosa isolates collected in 2013-2014 by the Antimicrobial Resistance Surveillance Program. The multi-locus sequence type, presence of antimicrobial resistance (AMR) determinants, and relatedness between the isolates were derived from the sequence data. The concordance between phenotypic and genotypic resistance was also determined.Carbapenem resistance was associated namely with loss-of function of the OprD porin, and acquisition of the metallo-β-lactamase VIM. The concordance between phenotypic and genotypic resistance was 93.27% overall for 6 antibiotics in 3 classes, but varied widely between aminoglycosides. The population of P. aeruginosa in the Philippines was diverse, with clonal expansions of XDR genomes belonging to multi-locus sequence types ST235, ST244, ST309, and ST773. We found evidence of persistence or reintroduction of the predominant clone ST235 in one hospital, as well as transfer between hospitals. Most of the ST235 genomes formed a distinct Philippine lineage when contextualized with international genomes, thus raising the possibility that this is a lineage unique to the Philippines. This was further supported by long-read sequencing of one representative XDR isolate, which revealed the presence of an integron carrying multiple resistance genes, including blaVIM-2, with differences in gene composition and synteny to other P. aeruginosa class 1 integrons described before.We produced the first comprehensive genomic survey of P. aeruginosa in the Philippines, which bridges the gap in genomic data from the Western Pacific region and will constitute the genetic background to contextualize ongoing prospective surveillance. Our results also highlight the importance of infection control interventions aimed to curtail the spread of international epidemic clone ST235 within the country.

Drug-resistant bacterial infections constitute a growing threat to public health globally 1. National networks of laboratory-based surveillance of antimicrobial resistance (AMR) monitor the emergence and spread of resistance and are central to the dissemination of these data to AMR stakeholders 2. Whole-genome sequencing (WGS) can support these efforts by pinpointing resistance mechanisms and uncovering transmission patterns 3, 4. However, genomic surveillance is rare in low- and middle-income countries (LMICs), which are predicted to be the most affected by AMR 5. We implemented WGS within the established Antimicrobial Resistance Surveillance Program (ARSP) of the Philippines via ongoing technology transfer, capacity building in and binational collaboration. In parallel, we conducted an initial large-scale retrospective sequencing survey to characterize bacterial populations and dissect resistance phenotypes of key bug-drug combinations, which is the focus of this article. Starting in 2010, the ARSP phenotypic data indicated increasing carbapenem resistance rates for Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae and Escherichia coli. We first identified that this coincided with a marked expansion of specific resistance phenotypes. By then linking the resistance phenotypes to genomic data, we revealed the diversity of genetic lineages (strains), AMR mechanisms, and AMR vehicles underlying this expansion. We discovered a previously unreported plasmid-driven hospital outbreak of carbapenem-resistant K. pneumoniae, uncovered the interplay of carbapenem resistance genes and plasmids in the geographic circulation of epidemic K. pneumoniae ST147, and found that carbapenem-resistant E. coli ST410 consisted of diverse lineages of global circulation that carried both international and local plasmids, resulting in a combination of carbapenemase genes variants previously unreported for this organism. Thus, the WGS data provided an enhanced understanding of the interplay between strains, genes and vehicles driving the dissemination of carbapenem resistance in the Philippines. In addition, our retrospective survey served both as the genetic background to contextualize local prospective surveillance, and as a comprehensive dataset for training in bioinformatics and genomic epidemiology. Continued prospective sequencing, capacity building and collaboration will strengthen genomic surveillance of AMR in the Philippines and the translation of genomic data into public-health action. We generated a blueprint for the integration of WGS and genomic epidemiology into an established national system of laboratory-based surveillance of AMR through international collaboration that can be adapted and utilized within other locations to tackle the global challenge of AMR.

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.

Lactobacilli have been consistently associated with dental caries for decades; however, knowledge of this group of bacteria in the etiology of the disease is limited to quantitative elucidation. Nowadays, explicit identification of oral Lactobacillus species is possible, despite their taxonomic complexity. Here we describe a combined approach involving both cultivation and genetic methods to ascertain and characterize the diversity and abundance of the Lactobacillus population in the oral cavities of children with severe early childhood caries (S-ECC). Eighty 3- to 6-year-old children (40 S-ECC and 40 caries free) who were seeking dental care at the Pediatric Dental Clinic of Bellevue Hospital in New York City were invited to participate in this study. Clinical data on socio-demographic information and oral health behavior were obtained from the primary caregiver. The data included a detailed dental examination, children’s medical history, and a questionnaire survey. Combined non-stimulated saliva and supra-gingival plaque samples were collected from each child and cultivated on selective media for quantitative measures of lactobacilli levels. The procedure for Lactobacillus species screening will include the random selection of 50 colonies per plate, extraction of DNA from each colony, and genotyping by arbitrarily primed polymerase chain reaction (AP-PCR). Each unique Lactobacillus AP-PCR genotype will be selected for taxonomic assessment by 16S rRNA gene sequencing analysis. Lactobacillus species will be identified by comparing the 16S rRNA sequences with the Ribosomal Database and the Human Oral Microbiome Database. Meanwhile, the same set of clinical samples will be independently subjected to genomic DNA isolation, 16S rRNA amplification with Lactobacillus genus-specific primers, sequencing, and taxonomic identification, both at genus and species levels with a customized pipeline. The distribution and phylogenetic differences of these Lactobacillus species will be compared between children with or without S-ECC. One of the main objectives of this study is to establish a study protocol for the identification and characterization of lactobacilli in the oral cavity. Future caries risk assessments can include lactobacilli counts (quantitative) and the presence/absence of specific cariogenic genetic signatures of a Lactobacillus species (qualitative) associated with S-ECC.

Comparative genomics is a popular method for the identification of microbial virulence determinants, especially since the sequencing of a large number of whole bacterial genomes from pathogenic and non-pathogenic strains has become relatively inexpensive. The bioinformatics pipelines for comparative genomics usually include gene prediction and annotation and can require significant computer power. To circumvent this, we developed a rapid method for genome-scale in silico subtractive hybridization, based on blastn and independent of feature identification and annotation. Whole genome comparisons by in silico genome subtraction were performed to identify genetic loci specific to Streptococcus mutans strains associated with severe early childhood caries (S-ECC), compared to strains isolated from caries-free (CF) children.The genome similarity of the 20 S. mutans strains included in this study, calculated by Simrank k-mer sharing, ranged from 79.5% to 90.9%, confirming this is a genetically heterogeneous group of strains. We identified strain-specific genetic elements in 19 strains, with sizes ranging from 200 to 39kb. These elements contained protein-coding regions with functions mostly associated with mobile DNA. We did not, however, identify any genetic loci consistently associated with dental caries, i.e., shared by all the S-ECC strains and absent in the CF strains. Conversely, we did not identify any genetic loci specific with the healthy group. Comparison of previously published genomes from pathogenic and carriage strains of Neisseria meningitidis with our in silico genome subtraction yielded the same set of genes specific to the pathogenic strains, thus validating our method.Our results suggest that S. mutans strains derived from caries active or caries free dentitions cannot be differentiated based on the presence or absence of specific genetic elements. Our in silico genome subtraction method is available as the Microbial Genome Comparison (MGC) tool, with a user-friendly JAVA graphical interface.

Visualization is frequently used to aid our interpretation of complex datasets. Within microbial genomics, visualizing the relationships between multiple genomes as a tree provides a framework onto which associated data (geographical, temporal, phenotypic and epidemiological) are added to generate hypotheses and to explore the dynamics of the system under investigation. Selected static images are then used within publications to highlight the key findings to a wider audience. However, these images are a very inadequate way of exploring and interpreting the richness of the data. There is, therefore, a need for flexible, interactive software that presents the population genomic outputs and associated data in a user-friendly manner for a wide range of end users, from trained bioinformaticians to front-line epidemiologists and health workers. Here, we present Microreact, a web application for the easy visualization of datasets consisting of any combination of trees, geographical, temporal and associated metadata. Data files can be uploaded to Microreact directly via the web browser or by linking to their location (e.g. from Google Drive/Dropbox or via API), and an integrated visualization via trees, maps, timelines and tables provides interactive querying of the data. The visualization can be shared as a permanent web link among collaborators, or embedded within publications to enable readers to explore and download the data. Microreact can act as an end point for any tool or bioinformatic pipeline that ultimately generates a tree, and provides a simple, yet powerful, visualization method that will aid research and discovery and the open sharing of datasets. Publisher PDF

Shigella sonnei is an emergent cause of diarrheal disease in middle-income countries. The organism causes endemic disease and is also associated with sporadic outbreaks in susceptible populations. In 2010 and 2011 there were two suspected outbreaks of diarrheal disease caused by S. sonnei in La Pampa province in central Argentina. Aiming to confirm these as outbreaks and provide insight into the relationship of the strains causing these infections we combined antimicrobial susceptibility testing and pulsed field gel electrophoresis (PFGE) with whole genome sequencing (WGS). Antimicrobial susceptibility testing suggested the two events were unrelated; organisms isolated in 2010 exhibited resistance to trimethoprim sulphate whereas the 2011 S. sonnei were non-susceptible against ampicillin, trimethoprim sulphate and cefpodoxime. PFGE profiling confirmed the likelihood of two independent outbreaks, separating the isolates into two main XbaI restriction profiles. We additionally performed WGS on 17 isolates associated with these outbreaks. The resulting phylogeny confirmed the PFGE structure and separated the organisms into two comparatively distantly related clones. Antimicrobial resistant genes were common, and the presence of an OXA-1 was likely associated with resistance to cefpodoxime in the second outbreak. We additionally identified novel horizontally transferred genetic material that may impinge on the pathogenic phenotype of the infecting strains. Our study shows that even with a lack of supporting routine data WGS is an indispensible method for the tracking and surveillance of bacterial pathogens during outbreaks and is becoming a vital tool for the monitoring of antimicrobial resistant strains of S. sonnei.

This month’s Genome Watch highlights how next-generation sequencing technologies provide crucial information during disease outbreaks and thus inform the public health response. This month’s Genome Watch highlights how next-generation sequencing technologies provide crucial information during disease outbreaks and thus inform the public health response.

Several methods for determining the diversity of Lactobacillus spp were evaluated with the purpose of developing a realistic approach for further studies. The patient population was comprised of young children with an oral disease called severe early childhood caries. The ultimate goal of these studies was to ascertain the role of lactobacilli in the caries process. To accomplish that goal, we evaluated several methods and approaches for determining diversity including AP-PCR, chromosomal DNA fingerprinting, denaturing gradient gel electrophoresis, and 16S rRNA gene sequencing. Central to these methods was the gathering and screening of isolates from cultivation medium. Using various estimates of diversity, we addressed the question as to how many isolates represent the overall diversity and how cultivation compares to non-cultivation techniques. Finally, we proposed a working approach for achieving the goals outlined framed by both practical constraints in terms of time, effort and efficacy while yielding a reliable outcome.

Candida albicans expresses specific virulence traits that promote disease establishment and progression. These traits include morphological transitions between yeast and hyphal growth forms that are thought to contribute to dissemination and invasion and cell surface adhesins that promote attachment to the host. Here, we describe the regulation of the adhesin gene ALS3 , which is expressed specifically during hyphal development in C. albicans . Using a combination of reporter constructs and regulatory mutants, we show that this regulation is mediated by multiple factors at the transcriptional level. The analysis of ALS3 promoter deletions revealed that this promoter contains two activation regions: one is essential for activation during hyphal development, while the second increases the amplitude of this activation. Further deletion analyses using the Renilla reniformis luciferase reporter delineate the essential activation region between positions −471 and −321 of the promoter. Further 5′ or 3′ deletions block activation. ALS3 transcription is repressed mainly by Nrg1 and Tup1, but Rfg1 contributes to this repression. Efg1, Tec1, and Bcr1 are essential for the transcriptional activation of ALS3 , with Tec1 mediating its effects indirectly through Bcr1 rather than through the putative Tec1 sites in the ALS3 promoter. ALS3 transcription is not affected by Cph2, but Cph1 contributes to full ALS3 activation. The data suggest that multiple morphogenetic signaling pathways operate through the promoter of this adhesin gene to mediate its developmental regulation in this major fungal pathogen.

Lactobacilli have been associated with dental caries for over a century. Here, we review the pertinent literature along with findings from our own study to formulate a working hypothesis about the natural history and role of lactobacilli. Unlike most indigenous microbes that stably colonize a host, lactobacilli appear to be planktonic, opportunistic settlers that can gather and multiply only in certain restrictive niches of the host, at least within the oral cavity. We postulate that the following essential requirements are necessary for sustained colonization of lactobacilli in humans: 1) a stagnant, retentive niche that is mostly anaerobic; 2) a low pH milieu; and 3) ready access to carbohydrates. Three sites on the human body meet these specifications: caries lesions, the stomach, and the vagina. Only a handful of Lactobacillus species is found in caries lesions, but they are largely absent in caries-free children. Lactobacilli present in caries lesions represent both a major contributor to caries progression and a major reservoir to the gastrointestinal (GI) tract. We extend the assertion from other investigators that lactobacilli found in the GI tract originate in the oral cavity by proposing that lactobacilli in the oral cavity arise from caries lesions. This, in turn, leads us to reflect on the health implications of the lactobacilli in the mouth and downstream GI and to ponder whether these or any of the Lactobacillus species are truly indigenous to the human GI tract or the oral cavity.

Lactobacilli are a diverse group of species that occupy diverse nutrient-rich niches associated with humans, animals, plants and food. They are used widely in biotechnology and food preservation, and are being explored as therapeutics. Exploiting lactobacilli has been complicated by metabolic diversity, unclear species identity and uncertain relationships between them and other commercially important lactic acid bacteria. The capacity for biotransformations catalysed by lactobacilli is an untapped biotechnology resource. Here we report the genome sequences of 213 Lactobacillus strains and associated genera, and their encoded genetic catalogue for modifying carbohydrates and proteins. In addition, we describe broad and diverse presence of novel CRISPR-Cas immune systems in lactobacilli that may be exploited for genome editing. We rationalize the phylogenomic distribution of host interaction factors and bacteriocins that affect their natural and industrial environments, and mechanisms to withstand stress during technological processes. We present a robust phylogenomic framework of existing species and for classifying new species., Lactobacillus is a lactic acid bacteria and has a wide range of application from use in probiotic food production to biotherapeutics. Here, the authors sequence and compare the genomes of 213 different Lactobacillus strains and related genera, and provide new insight into phylogenomic organization and adaptive immunity elements in this bacteria family.

Protein A-tagging has become an important tool in characterization of protein-protein interactions in many systems, allowing purification of multicomponent complexes under native conditions. Here we provide a set of vectors that allow protein A-tagging in Candida albicans, through addition of the tag to open reading frames. These vectors were successfully used to generate stably tagged proteins that were functional, shown to be localized appropriately or assembled into complexes. These new vectors comprise a useful addition to the C. albicans molecular toolbox.

We report the efficient enantioselective reduction of a number of β-ketoesters by mycelial and yeast-like forms of the dimorphic fungus Mucor rouxii in a whole-cell process. Mycelial cells, grown in aerobiosis, were efficient in water, whereas the yeast-like cells, grown in anaerobic medium, were both efficient in water and in organic solvents. Almost 100% of conversion with 97% of enantiomeric excess of the (S) forms of the reduced β-ketoesters was obtained at 15 g biomass (wet weight)/mmol substrate in two hours. The fungal spores, which are the physiologically resistant form of the fungus, also catalyzed the reductive process efficiently and stereoselectively. The freeze-dried as well as the warm-air dried yeast-like cells, rehydrated in a small volume of water, maintained the same efficiency and selectivity of the reaction in organic solvents as the fresh biomass up to at least 4 months. Fil: Mangone, Constanza P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina Fil: Pereyra, Elba Nora. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Argimón, Silvia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Moreno, Silvia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Baldessari, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina