Biology subjects

Rocha, E.

Publications and source records attributed to Rocha, E..

16 recordsLinked to original sources

bioRxiv2026

Genetic accessibility, not superior fitness, determines which anti-HBs antibody escape variants are selected in patients

Background and Aims: Genetic diversity within the hepatitis B virus (HBV) surface antigen (HBsAg) drives the emergence of immune escape variants, but studying this diversity in vivo has been limited by the difficulty of establishing infection from patient isolates. We aimed to perform unbiased in vivo screening of variants in the HBs antigenic loop for antibody escape and fitness, using synthetic DNA launch of HBV in human hepatocyte chimeric mice. Approach and Results: Direct intrahepatic injection (IHI) of barcoded, recombinant cccDNA established infection from up to 32,000 independent launch events of a genotype A strain and successfully launched clinical consensus sequences across the major genotypes. Using IHI, we performed deep mutational scanning of 4,608 codon variants across the HBs antigenic loop. Under control antibody treatment, diverse variants expanded, revealing differences in variant fitness in the absence of adaptive immune pressure. Anti-HBs monoclonal antibody treatment suppressed wild-type viremia while permitting breakthrough of resistant variants from the library. Sequencing identified strong enrichment for substitutions at G145 (G145Q, G145H, G145R). Notably, G145Q, rather than the clinically dominant G145R, showed the greatest fitness advantage, indicating that G145R's clinical prevalence does not reflect superior intrinsic fitness. Conclusions: Unbiased in vivo screening reveals that clinically observed HBV escape mutations reflect which substitutions are genetically accessible by single nucleotide change and compatible with the overlapping polymerase reading frame, rather than which confer optimal fitness. This approach establishes a platform for high-resolution mapping of viral variant fitness under antiviral selection pressure.

microbiology↗

bioRxiv2026

Antibodies with Engineered Fc Domains Having Absolute Binding Selectivity to either FcγRIIa or FcγRI Delineate the Respective Effector Phenotypes by Human Monocytes and Macrophages

IgG1 immune complexes bind to all the Fc{gamma} receptors (Fc{gamma}R) expressed on myeloid cells, making it challenging to determine the precise role of each Fc{gamma}R on Fc effector phenotypes. Here we report the engineering of Fc2KG, an aglycosylated human IgG1 Fc domain that binds with near physiological affinity to Fc{gamma}RIIa/b with no detectable binding to any other Fc{gamma}Rs. Crystallographic analysis elucidated the structural basis of how mutations in the Fc domain compensate for the absence of the N297 glycan and enable selective binding. Using single-cell phagocytosis assays, we show that particles opsonized with Fc-engineered antibodies formatted with Fc2KG or with an Fc domain that binds only Fc{gamma}RI (Fc5), are ingested by THP-1 cells with near identical kinetics. We find that with CD16+ primary human monocytes, selective Fc{gamma}RII engagement is a major contributor to the ADCP mediated by wild-type IgG1. Additionally, we showed that Fc2KG formatted antibodies induce high levels of GM-CSF. With M1-like monocyte-derived human macrophages, trastuzumab formatted with wild-type IgG1 Fc, with Fc2KG or Fc5 were all equally proficient in the trogocytotic killing of opsonized SK-BR-3 HER2+ cells but only Fc{gamma}RI engagement led to secretion of proinflammatory cytokines. Collectively, our results highlight how precisely tuned, Fc-engineered antibodies can be deployed to answer long-standing questions regarding the precise effector functions mediated by human Fc{gamma}Rs, information which is key for the optimization of therapeutic antibodies.

immunology↗

bioRxiv2025

Third-generation cephalosporin antibiotics induce phage bursts in the human gut microbiome.

The use of antibiotics disrupts the gut microbiota, potentially leading to long-term health issues and the spread of resistance. To investigate the impact of antibiotics on phage populations, we followed 22 healthy individuals two weeks before and up to six months after a three-day course of 3rd-generation cephalosporins. The populations of phages very rarely encoded antibiotic resistance genes and were mostly temperate including many phage-plasmids. Gut phages remained individual-specific even after microbiome perturbation by antibiotics. Yet, we found a 20% decline in phage diversity the day after treatment, alongside blooms of a few (mostly virulent) phages. We suggest that these temporary dominant phages contribute to the recovery of gut bacterial diversity through kill-the-winner dynamics. This is supported by the finding that several phages targeted Parabacteroides distasonis, a bacterium thriving after cephalosporin treatment, and which only proliferated when these phages were absent.Our findings suggest that phages play a crucial role in the gut microbiotas response to antibiotics by contributing to the restoration of microbial balance and diversity. HighlightsO_LIIn healthy individuals, cephalosporin antibiotics cause an approx. 20% decline in gut phage richness that is restored after 30 days C_LIO_LIHuman gut phage communities are specific of each individual, which is retained post-antibiotic treatment C_LIO_LIAntibiotic perturbation causes an increase in the number of dominant virulent phages supporting kill-the-winner dynamics as mechanisms for shaping bacterial diversity C_LIO_LIDominance of Parabacteroides distasonis (after cephalosporin treatment) is likely disrupted through its specific phages C_LI eTOCAntibiotic-induced disruption of the gut microbiome leads to a transient loss of microbiome diversity (bacterial and viral) and causes blooms of bacteria and their viruses. Our analysis suggests that these viruses prey on dominant bacteria, prevent their dominance, and contribute to the recovery of microbiome balance. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=96 SRC="FIGDIR/small/636470v2_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@98c366org.highwire.dtl.DTLVardef@1446921org.highwire.dtl.DTLVardef@51f941org.highwire.dtl.DTLVardef@1c328ed_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2024

Generalists in a Specialist World: Vibrio-Phages with Broad Host Range

The host range of a bacteriophage--the diversity of hosts it can infect--is central to understanding phage ecology and applications. While most well-characterized phages have narrow host ranges, broad-host-range phages represent an intriguing component of marine ecosystems. The genetic and evolutionary mechanisms driving their generalism remain poorly understood. In this study, we analyzed Schizotequatroviruses and their Vibrio crassostreae hosts, collected from an oyster farm. Schizotequatroviruses exhibit broad host ranges, large genomes (~252 kbp) encoding 26 tRNAs, and conserved genomic organization interspersed with recombination hotspots. These recombination events, particularly in regions encoding receptor-binding proteins and antidefense systems, highlight their adaptability to host resistance. Notably, some lineages demonstrated receptor-switching between OmpK and LamB, showcasing their evolutionary flexibility. Despite their broad host range, Schizotequatroviruses were rare in the environment. Their scarcity could not be attributed to burst size, which was comparable to other phages in vitro, but may result from ecological constraints or fitness trade-offs, such as their preference for targeting generalist vibrios in seawater rather than the patho-phylotypes selected in oyster farms. Our findings clarify the genetic and ecological trade-offs shaping Schizotequatrovirus generalism and provide a foundation for future phage applications in aquaculture and beyond.

microbiology↗

bioRxiv2024

15-Lipoxygenase-Mediated Lipid Peroxidation Regulates LRRK2 Kinase Activity

Mutations in leucine-rich repeat kinase 2 (LRRK2) that increase its kinase activity are strongly linked to genetic forms of Parkinsons disease (PD). However, the regulation of endogenous wild-type (WT) LRRK2 kinase activity remains poorly understood, despite its frequent elevation in idiopathic PD (iPD) patients. Various stressors such as mitochondrial dysfunction, lysosomal dyshomeostasis, or vesicle trafficking deficits can activate WT LRRK2 kinase, but the specific molecular mechanisms are not fully understood. We found that the production of 4-hydroxynonenal (4-HNE), a lipid hydroperoxidation end-product, is a common biochemical response to these diverse stimuli. 4-HNE forms post-translational adducts with Cys2024 and Cys2025 in the kinase activation loop of WT LRRK2, significantly increasing its kinase activity. Additionally, we discovered that the 4-HNE responsible for regulating LRRK2 is generated by the action of 15-lipoxygenase (15-LO), making 15-LO an upstream regulator of the pathogenic hyperactivation of LRRK2 kinase activity. Pharmacological inhibition or genetic ablation of 15-LO prevents 4-HNE post-translational modification of LRRK2 kinase and its subsequent pathogenic hyperactivation. Therefore, 15-LO inhibitors, or methods to lower 4-HNE levels, or the targeting of Cys2024/2025 could provide new therapeutic strategies to modulate LRRK2 kinase activity and treat PD.

neuroscience↗

bioRxiv2023

Belt and braces: two escape ways to maintain the cassette reservoir of large chromosomal integrons

Integrons are adaptive devices that capture, stockpile, shuffle and express gene cassettes thereby sampling combinatorial phenotypic diversity. Some integrons called sedentary chromosomal integrons (SCIs) can be massive structures containing hundreds of cassettes. Since most of these cassettes are non-expressed, it is not clear how they remain stable over long evolutionary timescales. Recently, it was found that the experimental inversion of the SCI of Vibrio cholerae led to a dramatic increase of the cassette excision rate associated to a fitness defect. Here, we question the evolutionary sustainability of this apparently counter selected genetic context through experimental evolution. We find that the integrase is rapidly inactivated and that the inverted SCI can recover its original orientation by homologous recombination between two insertion sequences (ISs) present in the array. These two outcomes of SCI inversion restore the normal growth and prevent the loss of cassettes, enabling SCIs to retain their roles as reservoirs of functions. These results illustrate an interesting interplay between gene orientation, genome rearrangement, bacterial fitness and demonstrate how integrons can benefit from their embedded ISs.

genetics↗

bioRxiv2023

Phage inducible chromosomal minimalist island (PICMI), a family of satellites of marine virulent phages

Phage satellites are genetic elements that hijack the phage machinery for their own dissemination. However, only few phage satellites have been characterized, and mechanisms by which they influence microbial evolution in nature are unclear. Here we identify a new family of satellites, the Phage Inducible Chromosomal Minimalist Island (PICMI), which is broadly distributed in the marine bacteria Vibrionaceae. PICMI is characterized by reduced gene content, does not encode genes for capsid remodeling and packages its DNA as a concatemer. PICMI is integrated in the bacterial host genome at the end of the fis regulator and encodes three core proteins necessary for excision and replication. PICMI is dependent on virulent phage particles to spread to other bacteria and confers host protection from other competitive phages, without interfering with its helper phage. The discovery of PICMI strongly suggests that phages, including virulent ones, play important roles for mobility of phage defense elements.

microbiology↗

bioRxiv2023

Type IV-A3 CRISPR-Cas systems drive inter-plasmid conflicts by acquiring spacers in trans

Type IV-A CRISPR-Cas systems are primarily encoded on plasmids and form multi-subunit ribonucleoprotein complexes with unknown biological functions. In contrast to other CRISPR-Cas types, they lack the archetypical CRISPR acquisition module and encode a DinG helicase instead of a nuclease component. Type IV-A3 systems are carried by large conjugative plasmids that often harbor multiple antibiotic-resistance genes. Although their CRISPR array contents suggest a role in inter-plasmid conflicts, this function and the underlying mechanisms have remained unexplored. Here, we demonstrate that a plasmid-encoded type IV-A3 CRISPR-Cas system co-opts the type I-E adaptation machinery from its clinical Klebsiella pneumoniae host to update its CRISPR array. Furthermore, we demonstrate that robust interference of conjugative plasmids and phages is elicited through CRISPR RNA-dependent transcriptional repression. By targeting plasmid core functions, type IV-A3 can prevent the uptake of incoming plasmids, limit their horizontal transfer, and destabilize co-residing plasmids, altogether supporting type IV-A3s involvement in plasmid competition. Collectively, our findings shed light on the molecular mechanisms and ecological function of type IV-A3 systems and have broad implications for understanding and countering the spread of antibiotic resistance in clinically relevant strains.

microbiology↗

bioRxiv2023

Differences in vertical and horizontal transmission dynamics shape plasmid distribution in clinical enterobacteria

Conjugative plasmids play a key role in the dissemination of antimicrobial resistance (AMR) genes across bacterial pathogens. AMR plasmids are widespread in clinical settings, but their distribution is not random, and certain associations between plasmids and bacterial clones are particularly successful. For example, the globally spread carbapenem resistance plasmid pOXA-48 can use a wide range of enterobacterial species as hosts, but it is usually associated with a small number of specific Klebsiella pneumoniae clones. These successful associations represent an important threat for hospitalized patients. However, knowledge remains limited about the factors determining AMR plasmid distribution in clinically relevant bacteria. Here, we combined in vitro and in vivo experimental approaches to analyze pOXA-48-associated AMR levels and conjugation dynamics in a collection of wild type enterobacterial strains isolated from hospitalized patients. Our results reveal significant variability in these traits across different bacterial hosts, with Klebsiella spp. strains showing higher pOXA-48-mediated AMR and conjugation frequencies than Escherichia coli strains. Using experimentally determined parameters, we developed a simple mathematical model to interrogate the contribution of AMR levels and conjugation permissiveness to plasmid distribution in bacterial communities. The simulations revealed that a small subset of clones, combining high AMR levels and conjugation permissiveness, play a critical role in stabilizing the plasmid in different polyclonal microbial communities. These results help to explain the preferential association of plasmid pOXA-48 with K. pneumoniae clones in clinical settings. More generally, our study reveals that species- and strain-specific variability in plasmid-associated phenotypes shape AMR evolution in clinically relevant bacterial communities. Significance statementConjugative plasmids disseminate AMR genes across bacterial pathogens. Understanding the rules governing plasmid dynamics in bacterial communities is therefore crucial to controlling the global AMR crisis. In this study, we analyzed the dynamics of an AMR plasmid of great clinical relevance, pOXA-48, in a collection of wild type bacteria recovered from hospitalized patients. We reported a high degree of variability in two key plasmid-associated phenotypes, AMR level and conjugation ability, across the collection of clinical bacteria. Using simulations based on the experimental results, we studied how successful associations between AMR plasmids and clinical strains can arise in bacterial communities. Our results revealed that accounting for variability in plasmid-associated phenotypes help to understand the evolution of AMR in clinical settings.

microbiology↗

bioRxiv2023

Comparative genomics of carbapenemase-producing Morganella spp.

BackgroundMorganella are opportunistic pathogens involved in various infections. In Morganella, intrinsic resistance to multiple antibiotics including colistin combined with the emergence of carbapenemase-producers (CP) strongly limits the antimicrobial armamentarium. MethodsFrom 2013 to 2021, 172 highly drug-resistant (XDR) Morganella isolates from 8 European countries and Canada, two reference strains from the Pasteur Institute collection and two susceptible isolates were characterized by WGS, antimicrobial susceptibility testing and biochemical tests. Complete genomes from Genbank (n=103) were included for genomic analysis. Intrinsic resistance mechanism to polymyxins was deciphered by combining genetic analysis with mass spectrometry on the lipid A. FindingsMorganella could be separated into 4 species named M. psychrotolerans, M. sibonii, M. morganii and a new species represented by a unique strain. Morganella morganii included two subspecies: M. morganii subsp. morganii (the most prevalent) and M. morganii subsp. intermedius. Intrinsic resistance to tetracycline and conservation of metabolic pathways correlated this refined taxonomy. CP were mostly identified among five high-risk clones of M. morganii subsp. morganii. A single nucleotide polymorphism (SNP) cut-off of 100 was used to decipher outbreaks involving this species. Cefepime-zidebactam and ceftazidime-avibactam were the most potent antimicrobials towards the 172 XDR Morganella spp. isolates of our collection (including 145 CP) except for metallo-{beta}-lactamase-producers. The intrinsic resistance to polymyxins corresponds to the addition of L-Ara4N on the lipid A. InterpretationThis global characterization of the widest collection of XDR Morganella spp. highlighted the need to clarify the taxonomy, deciphered intrinsic resistance mechanisms and paved the way for further genomic comparisons. FundingNone RESEARCH IN CONTEXTO_ST_ABSEvidence before this studyC_ST_ABSOn January 28th 2022, we have searched for the terms "Morganella" and "carbapenemase" in all published reports available in PubMed with no language restriction. We identified a total of 43 articles and most of them (41/43) corresponded to a report of a single isolate of carbapenemase-producing Morganella morganii. Only one article aimed to decipher the antimicrobial susceptibility on a collection of Proteus, Providencia and Morganella isolated from global hospitalized patients with intra-abdominal and urinary tract infections. However, this collection only included 7 M. morganii isolates. On March 2021, when we finished the inclusions in our collection, only 104 genomes of Morganella spp. were available in the NCBI database. Since September 2021, very few reports were published on carbapenemase-producing Morganella with the exception of a study from Xiang G et al. reported 40 multi-drug resistant M. morganii isolates recovered from three hospitals in China from 2014 to 2020. Unfortunately, this collection included only two carbapenemase-producing M. morganii isolates (one OXA-48 and one IMP-1). A report of KPC-producing M. morganii in Japan and a longitudinal study of carbapemase-producing Enterobactrales in Taiwan that did not focused on Morganella. We also searched in PubMed for the terms Morganella sibonii" or "Morganella psychrotolerans" in all published reports with no language restrictions. Our search identified a total of 20 articles. None of them was related to antimicrobial resistance and no study deciphered the Morganella spp. epidemiology on clinical isolates. Added values of this studyThis global characterization involved the widest collection of Morganella spp. isolates ever reported (barely doubling the number of Morganella spp. genomes in Genbank). In addition, 145 isolates of this worldwide collection made of 172 multidrug resistant Morganella spp. were carbapenemase producers for which therapeutic alternatives are scarce due to intrinsic resistance to last resort molecules, such as polymyxin. First, we found that cefepime-zidebactam and ceftazidime-avibactam were the most potent antimicrobials towards XDR Morganella spp. isolates except for metallo-{beta}-lactamase-producers. Then, we observed that carbapenemase-encoding genes were present in different Morganella species highlighting necessary changes in the taxonomy. Morganella genus could be divided into 4 species named M. psychrotolerans, M. sibonii, M. morganii and a new species represented by a unique strain. Morganella morganii includes two subspecies: M. morganii subsp. morganii (the most prevalent) and M. morganii subsp. intermedius. We demonstrated that this refined taxonomy correlated with the intrinsic resistance to tetracycline, which was found only in M. sibonii, as well as several metabolic pathways (e.g. trehalose assimilation, type III (T3SS) and type IV secretion system (T6SS), etc....). In addition, we highlighted five "high-risk" clones of carbapenemase-producing M. morganii subsp. morganii that have already disseminated worldwide. Combining whole genome sequencing (WGS) data with epidemiological investigations, we demonstrated that a cut-off of 100 single nucleotide polymorphisms (SNPs) could be used to discriminate clonally-related from sporadic independent isolates. This information is of the utmost importance since WGS is now considered as the reference method to identify and follow outbreaks. The intrinsic resistance of Morganella spp. to polymyxins was well-known but the underlying mechanism was unclear. Here, we demonstrated that the addition of L-Ara4N on the lipid A of Morganella is involved. Implications of all the available evidenceThe identification of "high-risk" clones among highly-drug resistant Morganella spp. paves the way of future investigations to better understand and hopefully limit the spread of these bugs. Additionally, our results identified new components and virulence factors of some Morganella species (e.g. T6SS and T3SS in M. sibonii) that deserve further investigation since they might be implicated in the bacterial lifestyle of this genus.

microbiology↗

bioRxiv2022

Evo-Scope: Fully automated assessment of correlated evolution on phylogenetic trees

O_LICorrelated evolution describes how multiple biological traits evolve together. Recently developed methods provide increasingly detailed results of correlated evolution, sometimes at elevated computational costs. C_LIO_LIHere, we present evo-scope, a fast and fully-automated pipeline with minimal input requirements to compute correlation between discrete traits evolving on a phylogenetic tree. Notably, we improve two of our previously developed tools that efficiently compute statistics of correlated evolution to characterize the nature, such as synergy or antagonism, and the strength of the interdependence between the traits. C_LIO_LIFurthermore, we improved the running time and implemented several additional features, such as genetic mapping, Bayesian Markov Chain Monte Carlo estimation, consideration of missing data and phylogenetic uncertainty. C_LIO_LIAs an application, we scan a published penicillin resistance data set of Streptococcus pneumoniae and characterize genetic mutations that correlate with antibiotic resistance. The pipeline is accessible both as a self-contained github repository (https://github.com/Maxime5G/EvoScope) and through a graphical galaxy interface (https://galaxy.pasteur.fr/u/maximeg/w/evoscope). C_LI

evolutionary biology↗

bioRxiv2022

Genetic drivers of chromosomal integron stability

Integrons are adaptive bacterial devices that rearrange promoter less gene cassettes into variable ordered arrays under stress conditions, to sample combinatorial phenotypic diversity. Chromosomal integrons often carry hundreds of silent gene cassettes, with integrase-mediated recombination leading to rampant DNA excision and integration, posing a potential threat to genome integrity. How this activity is regulated and controlled, particularly through selective pressures, to maintain such large cassette arrays is unknown. Here we show a key role of promoter-containing toxin-antitoxin (TA) cassettes as abortive systems that kill the cell when the overall cassette excision rate is too high. These results highlight the importance of TA cassettes regulating the cassette recombination dynamics and provide insight into the evolution and success of integrons in bacterial genomes. TeaserThe accumulation of cassette functions in integrons is ensured by toxin-antitoxin systems which kill the cell when the cassette excision rate is too high.

genetics↗

bioRxiv2021

Prophage-encoded hotspots of bacterial immune systems

The arms race between bacteria and phages led to the emergence of a variety of genetic systems used by bacteria to defend against viral infection, some of which were repurposed as powerful biotechnological tools. While numerous defense systems have been identified in genomic regions termed defense islands, it is believed that many more remain to be discovered. Here, we show that P2- like prophages and their P4-like satellites have genomic hotspots that represent a significant source of novel anti-phage systems. We validate the defense activity of 14 systems spanning various protein domains and describe PARIS, an abortive infection system triggered by a phage-encoded anti-restriction protein. Immunity hotspots are present across prophages of distant bacterial species, highlighting their biological importance in the competition between bacteria and phages.

microbiology↗

bioRxiv2019

Co-occurrence of multiple CRISPRs and cas clusters suggests epistatic interactions

Prokaryotes use CRISPR-Cas for adaptive immunity, but the reasons for the existence of multiple CRISPR and cas clusters remain poorly understood. We found that more than 40% of the genomes encoding a system show atypical genetic organizations. Their analysis revealed negative and positive epistatic interactions between Cas subtypes. The latter often result in one single complex locus with a shared adaptation module and diverse interference mechanisms, presumably to produce more effective immune systems. We typed CRISPRs that could not be unambiguously associated with a cas cluster and found that such complex loci tend to have unique type I repeats in multiple CRISPRs. In contrast, under-represented co-occurrences caused by functional interference or redundancy may lead to CRISPRs distant from cas genes. To investigate the origin of atypical CRISPR-Cas organizations, we analyzed plasmids and phages. Sets of nearly 2000 phages and 10000 prophages were almost devoid of CRISPR-Cas systems, but a sizeable fraction of plasmids had them. Isolated CRISPRs in plasmids were often compatible with the chromosomal cas clusters, suggesting that plasmids use CRISPRs to subvert host immunity. These results point to an important role for the interactions between multiple CRISPR and Cas in the function and evolution of bacterial immunity.

genomics↗

bioRxiv2018

Host range expansion and genetic plasticity drive the trade-off between integrative and extrachromosomal mobile genetic elements

Self-transmissible mobile genetic elements drive horizontal gene transfer between prokaryotes. Some of these elements integrate in the chromosome, whereas others replicate autonomously as plasmids. Recent works showed the existence of few differences, and occasional interconversion, between the two types of elements. Here, we enquired on why evolutionary processes have maintained the two types of mobile genetic elements by comparing integrative and conjugative elements (ICE) with extrachromosomal ones (conjugative plasmids) of the highly abundant MPFT conjugative type. We observed that plasmids encode more replicases, partition systems, and antibiotic resistance genes, whereas ICEs encode more integrases and metabolism-associated genes. ICEs and plasmids have similar average sizes, but plasmids are much more variable, have more DNA repeats, and exchange genes more frequently. On the other hand, we found that ICEs are more frequently transferred between distant taxa. We propose a model where differential plasticity and transmissibility range explain the co-occurrence of integrative and extra-chromosomal elements in microbial populations. In particular, the conversion from ICE to plasmid allows ICE to be more plastic, while the conversion from plasmid to ICE allows the expansion of the element s host range.

evolutionary biology↗

bioRxiv2017

Real-time search of all bacterial and viral genomic data

Genome sequencing of pathogens is now ubiquitous in microbiology, and the sequence archives are effectively no longer searchable for arbitrary sequences. Furthermore, the exponential increase of these archives is likely to be further spurred by automated diagnostics. To unlock their use for scientific research and real-time surveillance we have combined knowledge about bacterial genetic variation with ideas used in web-search, to build a DNA search engine for microbial data that can grow incrementally. We indexed the complete global corpus of bacterial and viral whole genome sequence data (447,833 genomes), using four orders of magnitude less storage than previous methods. The method allows future scaling to millions of genomes. This renders the global archive accessible to sequence search, which we demonstrate with three applications: ultra-fast search for resistance genes MCR1-3, analysis of host-range for 2827 plasmids, and quantification of the rise of antibiotic resistance prevalence in the sequence archives.

bioinformatics↗