CARD 2023: expanded curation, support for machine learning, and resistome prediction at the Comprehensive Antibiotic Resistance Database

Direct or DNA Extraction-Free Amplification and Quantification of Foodborne Pathogens

The use of direct nucleic acid amplification of pathogens from food matrices has the potential to reduce time to results over DNA extraction-based approaches as well as traditional culture-based approaches. Here we describe protocols for assay design and experiments for direct amplification of foodborne pathogens in food sample matrices using loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). The examples provided include the detection of Escherichia coli in milk samples and Salmonella in pork meat samples. This protocol includes relevant reagents and methods including obtaining target sequences, assay design, sample processing, and amplification. These methods, though used for specific example matrices, could be applied to many other foodborne pathogens and sample types.

Comprehensive physiological and genomic characterization of a potential probiotic strain, Lactiplantibacillus plantarum ILSF15, isolated from the gut of tribes of Odisha, India

Characterizing probiotic features of organisms isolated from diverse environments can lead to the discovery of novel strains with promising functional features and health attributes. The present study attempts to characterize a novel probiotic strain isolated from the gut of the tribal population of Odisha, India. Based on 16S rRNA-based phylogeny, the strain was identified as a species of the Lactiplantibacillus genus and was named Lactiplantibacillus plantarum strain ILSF15. The current investigation focuses on elucidating this strain's genetic and physiological properties associated with probiotic attributes such as biosafety risk, host adaptation/survival traits, and beneficial functional features. The novel strain was observed, in vitro, exhibiting features such as acid/bile tolerance, adhesion to the host enteric epithelial cells, cholesterol assimilation, and pathogen exclusion, indicating its ability to survive the harsh environment of the human GIT and resist the growth of harmful microorganisms. Additionally, the L. plantarum ILSF15 strain was found to harbor genes associated with the metabolism and synthesis of various bioactive molecules, including amino acids, carbohydrates, lipids, and vitamins, highlighting the organism's ability to efficiently utilize diverse resources and contribute to the host's nutrition and health. Several genes involved in host adaptation/survival strategies and host-microbe interactions were also identified from the ILSF15 genome. Moreover, L. plantarum strains, in general, were found to have an open pangenome characterized by high genetic diversity and the absence of specific lineages associated with particular habitats, signifying its versatile nature and potential applications in probiotic and functional food industries.

Staphylococcus aureus colonizing the skin microbiota of adults with severe atopic dermatitis exhibits genomic diversity and convergence in biofilm traits

Atopic dermatitis (AD) is a chronic inflammatory skin disorder exacerbated by Staphylococcus aureus colonization. The specific factors that drive S. aureus overgrowth and persistence in AD remain poorly understood. This study analyzed skin barrier functions and microbiome diversity in lesional (LE) and non-lesional (NL) forearm sites of individuals with severe AD compared to healthy control subjects (HS). Notable differences were found in transepidermal water loss, stratum corneum hydration, and microbiome composition. Cutibacterium was more prevalent in HS, while S. aureus and S. lugdunensis were predominantly found in AD LE skin. The results highlighted that microbial balance depends on inter-species competition. Specifically, network analysis at the genus level demonstrated that overall bacterial correlations were higher in HS, indicating a more stable microbial community. Notably, network analysis at the species level revealed that S. aureus engaged in competitive interactions in NL and LE but not in HS. Whole-genome sequencing (WGS) showed considerable genetic diversity among S. aureus strains from AD. Despite this variability, the isolates exhibited convergence in key phenotypic traits such as adhesion and biofilm formation, which are crucial for microbial persistence. These common phenotypes suggest an adaptive evolution, driven by competition in the AD skin microenvironment, of S. aureus and underscoring the interplay between genetic diversity and phenotypic convergence in microbial adaptation.

Unitig-centered pan-genome machine learning approach for predicting antibiotic resistance and discovering novel resistance genes in bacterial strains

In current genomic research, the widely used methods for predicting antimicrobial resistance (AMR) often rely on prior knowledge of known AMR genes or reference genomes. However, these methods have limitations, potentially resulting in imprecise predictions owing to incomplete coverage of AMR mechanisms and genetic variations. To overcome these limitations, we propose a pan-genome-based machine learning approach to advance our understanding of AMR gene repertoires and uncover possible feature sets for precise AMR classification. By building compacted de Brujin graphs (cDBGs) from thousands of genomes and collecting the presence/absence patterns of unique sequences (unitigs) for Pseudomonas aeruginosa, we determined that using machine learning models on unitig-centered pan-genomes showed significant promise for accurately predicting the antibiotic resistance or susceptibility of microbial strains. Applying a feature-selection-based machine learning algorithm led to satisfactory predictive performance for the training dataset (with an area under the receiver operating characteristic curve (AUC) of > 0.929) and an independent validation dataset (AUC, approximately 0.77). Furthermore, the selected unitigs revealed previously unidentified resistance genes, allowing for the expansion of the resistance gene repertoire to those that have not previously been described in the literature on antibiotic resistance. These results demonstrate that our proposed unitig-based pan-genome feature set was effective in constructing machine learning predictors that could accurately identify AMR pathogens. Gene sets extracted using this approach may offer valuable insights into expanding known AMR genes and forming new hypotheses to uncover the underlying mechanisms of bacterial AMR.

Elucidation of critical chemical moieties of metallo-β-lactamase inhibitors and prioritisation of target metallo-β-lactamases

The urgent demand for effective countermeasures against metallo-β-lactamases (MBLs) necessitates development of novel metallo-β-lactamase inhibitors (MBLIs). This study is dedicated to identifying critical chemical moieties within previously developed MBLIs, and critical MBLs should serve as the target in MBLI evaluations. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a systematic literature analysis was conducted, and the NCBI RefSeq genome database was exploited to access the abundance profile and taxonomic distribution of MBLs and their variant types. Through the implementation of two distinct systematic approaches, we elucidated critical chemical moieties of MBLIs, providing pivotal information for rational drug design. We also prioritised MBLs and their variant types, highlighting the imperative need for comprehensive testing to ensure the potency and efficacy of the newly developed MBLIs. This approach contributes valuable information to advance the field of antimicrobial drug discovery.

IS6 family insertion sequences promote optrA dissemination between plasmids varying in transfer abilities

Plasmids are the primary vectors for intercellular transfer of the oxazolidinone and phenicol cross-resistance gene optrA, while insertion sequences (ISs) are mobile genetic elements that can mobilize plasmid-borne optrA intracellularly. However, little is known about how the IS-mediated intracellular mobility facilitates the dissemination of the optrA gene between plasmid categories that vary in transfer abilities, including non-mobilizable, mobilizable, and conjugative plasmids. Here, we performed a holistic genomic study of 52 optrA-carrying plasmids obtained from searches guided by the Comprehensive Antibiotic Resistance Database. Among the 132 ISs identified within 10 kbp from the optrA gene in the plasmids, IS6 family genes were the most prevalent (86/132). Homologous gene arrays containing IS6 family genes were shared between different plasmids, especially between mobilizable and conjugative plasmids. All these indicated the central role of IS6 family genes in disseminating plasmid-borne optrA. Thirty-three of the 52 plasmids were harbored by Enterococcus faecalis found mainly in humans and animals. By Nanopore sequencing and inverse PCR, the potential of the enterococcal optrA to be transmitted from a mobilizable plasmid to a conjugative plasmid mediated by IS6 family genes was further confirmed in Enterococcus faecalis strains recovered from the effluents of anaerobic digestion systems for treating chicken manure. Our findings highlight the increased intercellular transfer abilities and dissemination risk of plasmid-borne optrA gene caused by IS-mediated intracellular mobility, and underscore the importance of routinely monitoring the dynamic genetic contexts of clinically important antibiotic resistance genes to effectively control this critical public health threat. KEY POINTS: • IS6 was prevalent in optrA-plasmids varying in intercellular transfer abilities. • Enterococcal optrA-plasmids were widespread among human, animal, and the environment. • IS6 elevated the dissemination risk of enterococcal optrA-plasmids.

Genetic traits and transmission of antimicrobial resistance characteristics of cephalosporin resistant Escherichia coli in tropical aquatic environments

This study investigates the genetic traits and transmission mechanisms of cephalosporin-resistant Escherichia coli in tropical aquatic environments in Singapore. From 2016 to 2020, monthly samples were collected from wastewater treatment plants, marine niches, community sewage, beaches, reservoirs, aquaculture farms, and hospitals, yielding 557 isolates that were analyzed for antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) using genomic methods. Findings reveal significant genotypic similarities between environmental and hospital-derived strains, particularly the pandemic E. coli ST131. Environmental strains exhibited high levels of intrinsic resistance mechanisms, including mutations in porins and efflux pumps, with key ARGs such as CMY-2 and NDM-9 predominantly carried by MGEs, which facilitate horizontal gene transfer. Notably, pathogenic EPEC and EHEC strains were detected in community sewage and aquaculture farms, posing substantial public health risks. This underscores the critical role of these environments as reservoirs for multidrug-resistant pathogens and emphasizes the interconnectedness of human activities and environmental health.

Advances, opportunities, and challenges in methods for interrogating the structure activity relationships of natural products

Time span in literature: 1985-early 2024Natural products play a key role in drug discovery, both as a direct source of drugs and as a starting point for the development of synthetic compounds. Most natural products are not suitable to be used as drugs without further modification due to insufficient activity or poor pharmacokinetic properties. Choosing what modifications to make requires an understanding of the compound's structure-activity relationships. Use of structure-activity relationships is commonplace and essential in medicinal chemistry campaigns applied to human-designed synthetic compounds. Structure-activity relationships have also been used to improve the properties of natural products, but several challenges still limit these efforts. Here, we review methods for studying the structure-activity relationships of natural products and their limitations. Specifically, we will discuss how synthesis, including total synthesis, late-stage derivatization, chemoenzymatic synthetic pathways, and engineering and genome mining of biosynthetic pathways can be used to produce natural product analogs and discuss the challenges of each of these approaches. Finally, we will discuss computational methods including machine learning methods for analyzing the relationship between biosynthetic genes and product activity, computer aided drug design techniques, and interpretable artificial intelligence approaches towards elucidating structure-activity relationships from models trained to predict bioactivity from chemical structure. Our focus will be on these latter topics as their applications for natural products have not been extensively reviewed. We suggest that these methods are all complementary to each other, and that only collaborative efforts using a combination of these techniques will result in a full understanding of the structure-activity relationships of natural products.

Complete Genome Sequence and Probiotic Characterization of Lactobacillus delbrueckii subsp. Indicus DC-3 Isolated from Traditional Indigenous Fermented Milk

In this study, Lactobacillus delbrueckii subsp. indicus DC-3 was isolated from Indian traditional indigenous fermented milk Dahi and identified using whole genome sequencing. The safety of the strain was evaluated using genetic and phenotypic analyses, such as the presence of virulence factors, mobile and insertion elements, plasmids, antibiotic resistance, etc. Besides this, the strain was comprehensively investigated for in vitro probiotic traits, biofilm formation, antibacterials, and exopolysaccharide (EPS) production. In results, the strain showed a single circular chromosome (3,145,837 bp) with a GC content of 56.73%, a higher number of accessory and unique genes, an open pan-genome, and the absence of mobile and insertion elements, plasmids, virulence, and transmissible antibiotic resistance genes. The strain was capable of surviving in gastric juice (83% viability at 3 h) and intestinal juice (71% viability at 6 h) and showed 42.5% autoaggregation, adhesion to mucin, 8.7% adhesion to xylene, and 8.3% adhesion to Caco-2 cells. The γ-hemolytic nature, usual antibiotic susceptibility profile, and negative results for mucin and gelatin degradation ensure the safety of the strain. The strain produced 10.5 g/L of D-lactic acid and hydrogen peroxide, capable of inhibiting and co-aggregating Escherichia coli MTCC 1687, Proteus mirabilis MTCC 425, and Candida albicans ATCC 14,053. In addition, the strain showed 90 mg/L EPS (48 h) and biofilm formation. In conclusion, this study demonstrates that L. delbrueckii subsp. indicus DC-3 is unique and different than previously reported L. delbrueckii subsp. indicus strains and is a safe potential probiotic candidate.

Revealing the Genetic Diversity of Chinese Chlamydia trachomatis Strains Directly From Clinical Samples Through Selective Whole Genome Amplification

BACKGROUND

Chlamydia trachomatis is the causative agent of the most prevalent bacterial sexually transmitted infections globally. Whole genome sequencing is essential for molecular Chlamydia surveillance; however, its application is hampered by the pathogen's low abundance in clinical specimens and the expensive labor-intensive nature of existing enrichment methodologies for Chlamydia.

METHODS

We developed a targeted whole genome amplification tool termed SWITCH by integrating phi29 DNA polymerase-mediated amplification with meticulously designed primer sets to enrich the C trachomatis genome, followed by whole genome sequencing. This method underwent evaluation through testing synthetic and clinical specimens.

RESULTS

SWITCH demonstrated robust ability to achieve up to 98.3% genomic coverage of C trachomatis from as few as 26.4 genomic copies present in synthetic specimens, and it exhibited excellent performance across diverse C trachomatis serovars. Utilizing SWITCH, we directly generated 21 Chlamydia genomes from 26 clinical samples, enabling us to gain insights into the genetic relationships and phylogeny of current Chlamydia strains circulating in the country. Remarkably, this study marked the first instance of generating Chinese Chlamydia genomes directly from clinical samples.

CONCLUSIONS

SWITCH represents a practical cost-efficient approach to enrich the Chlamydia genome directly from clinical specimens, offering an efficient avenue for molecular surveillance of Chlamydia.

The interplay between mobilome and resistome in Staphylococcus aureus

Antibiotic resistance genes (ARGs) in Staphylococcus aureus can disseminate vertically through successful clones, but also horizontally through the transfer of genes conveyed by mobile genetic elements (MGEs). Even though underexplored, MGE/ARG associations in S. aureus favor the emergence of multidrug-resistant clones, which are challenging therapeutic success in both human and animal health. This study investigated the interplay between the mobilome and the resistome of more than 10,000 S. aureus genomes from human and animal origin. The analysis revealed a remarkable diversity of MGEs and ARGs, with plasmids and transposons being the main carriers of ARGs. Numerous MGE/ARG associations were identified, suggesting that MGEs play a critical role in the dissemination of resistance. A high degree of similarity was observed in MGE/ARG associations between human and animal isolates, highlighting the potential for unrestricted spread of ARGs between hosts. Our results showed that in parallel to clonal expansion, MGEs and their associated ARGs can spread across different strain types sequence types (STs), favoring the evolution of these clones and their adaptation in selective environments. The high variability of MGE/ARG associations within individual STs and their spread across several STs highlight the crucial role of MGEs in shaping the S. aureus resistome. Overall, this study provides valuable insights into the complex interplay between MGEs and ARGs in S. aureus, emphasizing the need to elucidate the mechanisms governing the epidemic success of MGEs, particularly those implicated in ARG transfer.IMPORTANCEThe research presented in this article highlights the importance of understanding the interactions between mobile genetic elements (MGEs) and antibiotic resistance genes (ARGs) carried by Staphylococcus aureus, a versatile bacterium that can be both a harmless commensal and a dangerous pathogen for humans and animals. S. aureus has a great capacity to acquire and disseminate ARGs, enabling efficient adaption to various environmental or clinical conditions. By analyzing a large data set of S. aureus genomes, we highlighted the substantial role of MGEs, particularly plasmids and transposons, in disseminating ARGs within and between S. aureus populations, bypassing host barriers. Given that multidrug-resistant S. aureus strains are classified as a high-priority pathogen by global health organizations, this knowledge is crucial for understanding the complex dynamics of transmission of antibiotic resistance in this species.

An outbreak of blaKPC-4- and blaVIM-1-producing Klebsiella pneumoniae and Klebsiella variicola at a single hospital in South Korea

BACKGROUND

The dissemination of Klebsiella spp. producing multiple carbapenemases has been increasingly recognized. Between July 2019 and August 2021, ten patients were found to carry Klebsiella spp. co-harboring blaKPC-4 and blaVIM-1 across multiple wards at a Korean hospital, and one isolate was recovered from a hand-washing sink, more than a year after the outbreak. This study aimed to investigate the outbreak and conduct a genomic study of these isolates.

METHODS

Whole-genome sequencing, including long-read sequencing, was performed to analyze plasmid structures and mobile genetic elements (MGEs). Bioinformatics analyses were performed to trace clonal transmission chains and horizontal gene transfer.

RESULTS

The findings suggested that the inter-ward spread of Klebsiella spp. seemed to be facilitated by healthcare worker contact or patient movement. Of the nine isolates collected (eight clinical and one environmental), seven (including the environmental isolate) were identified as K. pneumoniae (ST3680) and two were K. variicola (single-locus variant of ST5252). These isolates showed high genetic relatedness within their species and harbored the IncHI5B plasmid carrying both blaKPC-4 and blaVIM-1 (pKPCVIM.1). On this plasmid, blaVIM-1 was located in the Class 1 integron associated with IS1326::IS1353 (In2), and Tn4401b carrying blaKPC-4 was inserted into IS1326::IS1353, creating a novel MGE construct (In2_blaVIM-1-Tn4401b_blaKPC-4).

CONCLUSION

The hospital-wide spread of blaKPC-4 and blaVIM-1 was facilitated by clonal spread and horizontal plasmid transfer. The persistence of this strain in the hospital sink suggests a potential reservoir of the strain. Understanding the transmission mechanisms of persistent pathogens is important for improving infection control strategies in hospitals.

Complete genome sequence of a high-risk Escherichia coli ST10 isolated from avian feces in Pakistan

We present the complete genome sequence of Escherichia coli strain PEC1009 isolated from avian feces in Pakistan. The strain belongs to sequence type (ST) 10, a high-risk clone. The strain possesses two plasmids, and various plasmid-borne antibiotic resistance genes and chromosome-borne virulence factor genes were identified in its genome.

Hazard characterization of antibiotic-resistant Aeromonas spp. isolated from mussel and oyster shellstock available for retail purchase in Canada

Surveillance and monitoring of foods for the presence of antimicrobial-resistant (AMR) bacteria is required to assess the risks these bacteria pose to human health. Frequently consumed raw or lightly cooked, live bivalve shellfish such as mussels and oysters can be a source of exposure to AMR bacteria. This study sought to determine the prevalence of third generation cephalosporin (3GC) and carbapenem resistant bacteria in live mussel and oyster shellstock available for retail purchase through the course of one calendar year. Just over half of the 180 samples (52%) tested positive for the presence 3GC-resistant bacteria belonging to thirty distinct bacterial species. Speciation of the isolates was carried out using the Bruker MALDI Biotyper. Serratia spp., Aeromonas spp., and Rahnella spp. were the most frequently isolated groups of bacteria. Antibiotic resistance testing confirmed reduced susceptibility for 3GCs and/or carbapenems in 15 of the 29 Aeromonas isolates. Based on AMR patterns, and species identity, a sub-set of ten Aeromonas strains was chosen for further characterization by whole genome sequence analysis. Genomic analysis revealed the presence of multiple antibiotic resistance and virulence genes. A number of mobile genetic elements were also identified indicating the potential for horizontal gene transfer. Differences in gene detection by the bioinformatic tools and databases used (ResFinder. CARD RGI, PlasmidFinder, and MobSuite) are discussed. This study highlights the strengths and limitations of using genomics tools to perform hazard characterization of diverse foodborne bacterial species.

Antibiotic resistance and draft genome profiles of 10 Streptococcus pneumoniae and 3 Streptococcus pseudopneumoniae strains isolated from the nasopharynx of people living with human immunodeficiency virus in Ghana

Genomic data on clinically important bacteria species such as Streptococcus pneumoniae and Streptococcus pseudopneumoniae from low- and middle-income countries, including Ghana, are scarce. In this study, we provide data on antimicrobial resistance (AMR) and whole-genome profiles of a collection of streptococci species to support AMR surveillance efforts in the country.

Whole-genome sequencing of Klebsiella pneumoniae MDR circulating in a pediatric hospital setting: a comprehensive genome analysis of isolates from Guayaquil, Ecuador

BACKGROUND

Klebsiella pneumoniae is the major cause of nosocomial infections worldwide and is related to a worsening increase in Multidrug-Resistant Bacteria (MDR) and virulence genes that seriously affect immunosuppressed patients, long-stay intensive care patients, elderly individuals, and children. Whole-Genome Sequencing (WGS) has resulted in a useful strategy for characterizing the genomic components of clinically important bacteria, such as K. pneumoniae, enabling them to monitor genetic changes and understand transmission, highlighting the risk of dissemination of resistance and virulence associated genes in hospitals. In this study, we report on WGS 14 clinical isolates of K. pneumoniae from a pediatric hospital biobank of Guayaquil, Ecuador.

RESULTS

The main findings revealed pronounced genetic heterogeneity among the isolates. Multilocus sequencing type ST45 was the predominant lineage among non-KPC isolates, whereas ST629 was found more frequently among KPC isolates. Phylogenetic analysis suggested local transmission dynamics. Comparative genomic analysis revealed a core set of 3511 conserved genes and an open pangenome in neonatal isolates. The diversity of MLSTs and capsular types, and the high genetic diversity among these isolates indicate high intraspecific variability. In terms of virulence factors, we identified genes associated with adherence, biofilm formation, immune evasion, secretion systems, multidrug efflux pump transporters, and a notably high number of genes related to iron uptake. A large number of these genes were detected in the ST45 isolate, whereas iron uptake yersiniabactin genes were found exclusively in the non-KPC isolates. We observed high resistance to commonly used antibiotics and determined that these isolates exhibited multidrug resistance including β-lactams, aminoglycosides, fluoroquinolones, quinolones, trimetropins, fosfomycin and macrolides; additionally, resistance-associated point mutations and cross-resistance genes were identified in all the isolates. We also report the first K. pneumoniae KPC-3 gene producers in Ecuador.

CONCLUSIONS

Our WGS results for clinical isolates highlight the importance of MDR in neonatal K. pneumoniae infections and their genetic diversity. WGS will be an imperative strategy for the surveillance of K. pneumoniae in Ecuador, and will contribute to identifying effective treatment strategies for K. pneumoniae infections in critical units in patients at stratified risk.

Characterization of acquired β-lactamases in Pseudomonas aeruginosa and quantification of their contributions to resistance

Pseudomonas aeruginosa is a highly problematic opportunistic pathogen that causes a range of different infections. Infections are commonly treated with β-lactam antibiotics, including cephalosporins, monobactams, penicillins, and carbapenems, with carbapenems regarded as antibiotics of last resort. Isolates of P. aeruginosa can contain horizontally acquired bla genes encoding β-lactamase enzymes, but the extent to which these contribute to β-lactam resistance in this species has not been systematically quantified. The overall aim of this research was to address this knowledge gap by quantifying the frequency of β-lactamase-encoding genes in P. aeruginosa and by determining the effects of β-lactamases on susceptibility of P. aeruginosa to β-lactams. Genome analysis showed that β-lactamase-encoding genes are present in 3% of P. aeruginosa but are enriched in carbapenem-resistant isolates (35%). To determine the substrate antibiotics, 10 β-lactamases were expressed from an integrative plasmid in the chromosome of P. aeruginosa reference strain PAO1. The β-lactamases reduced susceptibility to a variety of clinically used antibiotics, including carbapenems (meropenem, imipenem), penicillins (ticarcillin, piperacillin), cephalosporins (ceftazidime, cefepime), and a monobactam (aztreonam). Different enzymes acted on different β-lactams. β-lactamases encoded by the genomes of P. aeruginosa clinical isolates had similar effects to the enzymes expressed in strain PAO1. Genome engineering was used to delete β-lactamase-encoding genes from three carbapenem-resistant clinical isolates and increased susceptibility to substrate β-lactams. Our findings demonstrate that acquired β-lactamases play an important role in β-lactam resistance in P. aeruginosa, identifying substrate antibiotics for a range of enzymes and quantifying their contributions to resistance.IMPORTANCEPseudomonas aeruginosa is an extremely problematic pathogen, with isolates that are resistant to the carbapenem class of β-lactam antibiotics being in critical need of new therapies. Genes encoding β-lactamase enzymes that degrade β-lactam antibiotics can be present in P. aeruginosa, including carbapenem-resistant isolates. Here, we show that β-lactamase genes are over-represented in carbapenem-resistant isolates, indicating their key role in resistance. We also show that different β-lactamases alter susceptibility of P. aeruginosa to different β-lactam antibiotics and quantify the effects of selected enzymes on β-lactam susceptibility. This research significantly advances the understanding of the contributions of acquired β-lactamases to antibiotic resistance, including carbapenem resistance, in P. aeruginosa and by implication in other species. It has potential to expedite development of methods that use whole genome sequencing of infecting bacteria to inform antibiotic treatment, allowing more effective use of antibiotics, and facilitate the development of new antibiotics.

Unveiling the multifaceted potential of Pseudomonas khavaziana strain SR9: a promising biocontrol agent for wheat crown rot

Fusarium pseudograminearum, a soil-borne fungus, is the cause of the devastating wheat disease known as wheat crown rot (WCR). The persistence of this pathogen in the soil and crop residues contributes to the increased occurrence and severity of WCR. Therefore, developing effective strategies to prevent and manage WCR is of great importance. In this study, we isolated a bacterial strain, designated as SR9, from the stem of wheat, that exhibited potent antagonistic effects against F. pseudograminearum, as well as the biocontrol efficacy of SR9 on WCR was quantified at 83.99% ± 0.11%. We identified SR9 as Pseudomonas khavaziana and demonstrated its potential as a plant probiotic. SR9 displayed broad-spectrum antagonism against other fungal pathogens, including Neurospora dictyophora, Botrytis californica, and Botryosphaeria dothidea. Whole-genome sequencing analysis revealed that SR9 harbored genes encoding various cell wall-degrading enzymes, cellulases, and lipases, along with antifungal metabolites, which are responsible for its antagonistic activity. Gene knockout and quantitative PCR analyses reveal that phenazine is the essential factor for antagonism. SR9 possessed genes related to auxin synthesis, flagellar biosynthesis, biofilm adhesion, and the chemotaxis system, which play pivotal roles in plant colonization and growth promotion; we also evaluated the effects of SR9 on plant growth in wheat and Arabidopsis. Our findings strongly suggest that SR9 holds great promise as a biocontrol agent for WCR in sustainable agriculture.IMPORTANCEThe escalating prevalence of wheat crown rot, primarily attributed to Fusarium pseudograminearum, necessitates the development of cost-effective and eco-friendly biocontrol strategies. While plant endophytes are recognized for their biocontrol potential, reports on effective strains targeting wheat crown rot are sparse. This study introduces the Pseudomonas khavaziana SR9 strain as an efficacious antagonist to the wheat crown rot pathogen Fusarium pseudograminearum. Demonstrating a significant reduction in wheat crown rot incidence and notable plant growth promotion, SR9 emerges as a key contributor to plant health and agricultural sustainability. Our study outlines a biological approach to tackle wheat crown rot, establishing a groundwork for innovative sustainable agricultural practices.

Genome characterization of Shewanella algae in Hainan Province, China

Shewanella algae is an emerging marine zoonotic pathogen. In this study, we first reported the Shewanella algae infections in patients and animals in Hainan Province, China. Currently, there is still relatively little known about the whole-genome characteristics of Shewanella algae in most tropical regions, including in southern China. Here, we sequenced the 62 Shewanella algae strains isolated from Hainan Province and combined with the whole genomes sequences of 144 Shewanella algae genomes from public databases to analyze genomic features. Phylogenetic analysis revealed that Shewanella algae is widely distributed in the marine environments of both temperate and tropical countries, exhibiting close phylogenetic relationships with genomes isolated from patients, animals, and plants. Thereby confirming that exposure to marine environments is a risk factor for Shewanella algae infections. Average nucleotide identity analysis indicated that the clonally identical genomes could be isolated from patients with different sample types at different times. Pan-genome analysis identified a total of 21,909 genes, including 1,563 core genes, 8,292 strain-specific genes, and 12,054 accessory genes. Multiple putative virulence-associated genes were identified, encompassing 14 categories and 16 subcategories, with 171 distinct virulence factors. Three different plasmid replicon types were detected in 33 genomes. Eleven classes of antibiotic resistance genes and 352 integrons were identified. Antimicrobial susceptibility testing revealed a high resistance rate to imipenem and colistin among the strains studied, with 5 strains exhibiting multidrug resistance. However, they were all sensitive to amikacin, minocycline, and tigecycline. Our findings clarify the genomic characteristics and population structure of Shewanella algae in Hainan Province. The results offer insights into the genetic basis of pathogenicity in Shewanella algae and enhance our understanding of its global phylogeography.

Pan-pathogen deep sequencing of nosocomial bacterial pathogens in Italy in spring 2020: a prospective cohort study

BACKGROUND

Nosocomial infections pose a considerable risk to patients who are susceptible, and this is particularly acute in intensive care units when hospital-associated bacteria are endemic. During the first wave of the COVID-19 pandemic, the surge of patients presented a significant obstacle to the effectiveness of infection control measures. We aimed to assess the risks and extent of nosocomial pathogen transmission under a high patient burden by designing a novel bacterial pan-pathogen deep-sequencing approach that could be integrated with standard clinical surveillance and diagnostics workflows.

METHODS

We did a prospective cohort study in a region of northern Italy that was severely affected by the first wave of the COVID-19 pandemic. Inpatients on both ordinary and intensive care unit (ICU) wards at the San Matteo hospital, Pavia were sampled on multiple occasions to identify bacterial pathogens from respiratory, nasal, and rectal samples. Diagnostic samples collected between April 7 and May 10, 2020 were cultured on six different selective media designed to enrich for Acinetobacter baumannii, Escherichia coli, Enterococcus faecium, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pneumoniae, and DNA from each plate with positive growth was deep sequenced en masse. We used mSWEEP and mGEMS to bin sequencing reads by sequence cluster for each species, followed by mapping with snippy to generate high quality alignments. Antimicrobial resistance genes were detected by use of ARIBA and CARD. Estimates of hospital transmission were obtained from pairwise bacterial single nucleotide polymorphism distances, partitioned by within-patient and between-patient samples. Finally, we compared the accuracy of our binned Acinetobacter baumannii genomes with those obtained by single colony whole-genome sequencing of isolates from the same hospital.

FINDINGS

We recruited patients from March 1 to May 7, 2020. The pathogen population among the patients was large and diverse, with 2148 species detections overall among the 2418 sequenced samples from the 256 patients. In total, 55 sequence clusters from key pathogen species were detected at least five times. The antimicrobial resistance gene prevalence was correspondingly high, with key carbapenemase and extended spectrum ß-lactamase genes detected in at least 50 (40%) of 125 patients in ICUs. Using high-resolution mapping to infer transmission, we established that hospital transmission was likely to be a significant mode of acquisition for each of the pathogen species. Finally, comparison with single colony Acinetobacter baumannii genomes showed that the resolution offered by deep sequencing was equivalent to single-colony sequencing, with the additional benefit of detection of co-colonisation of highly similar strains.

INTERPRETATION

Our study shows that a culture-based deep-sequencing approach is a possible route towards improving future pathogen surveillance and infection control at hospitals. Future studies should be designed to directly compare the accuracy, cost, and feasibility of culture-based deep sequencing with single colony whole-genome sequencing on a range of bacterial species.

FUNDING

Wellcome Trust, European Research Council, Academy of Finland Flagship program, Trond Mohn Foundation, and Research Council of Norway.

Gut colonization with antibiotic-resistant Escherichia coli pathobionts leads to disease severity in ulcerative colitis

BACKGROUND

Escherichia coli is a Gram-negative commensal of human gut. Surprisingly, the role of E. coli in the pathogenesis of ulcerative colitis (UC) has not been explored until now.

METHODS

Human gut microbiota composition and meta-gut resistome were evaluated using metagenomics. Antibiotic susceptibility of E. coli isolates against different class of antibiotics was investigated. Further, the genome sequence analysis of E. coli isolates was performed to gain insight into the antimicrobial resistance (AMR) mechanism and virulence factors. Gut proteome of UC and non-UC was examined to understand the effect of resistant bacteria on host physiology.

RESULTS

In UC patients, meta-gut resistome was found to be dominated by AMR genes (829) compared to healthy controls (HC) [518]. The metagenome study revealed a higher prevalence of AMR genes in the rural population (378 in HC; 607 in UC) compared to the urban (340 in HC; 578 in UC). Approximately, 40% of all E. coli isolates were multi-drug resistant (MDR), with higher prevalence in UC (43.75%) compared to HC (33.33%). Up-regulated expression of antimicrobial human proteins (lactotransferrin, azurocidin, cathepsin G, neutrophil elastase, and neutrophil defensin 3) and inflammatory mediator (Protein S100-A9 and Protein S100-A8) suggest microbial infection in UC gut.

CONCLUSIONS

In addition to the conventional culturomics method, a multi-omics strategy provides deeper insights into the disease etiology, emergence of MDR pathobionts, and their roles in the disruption of the healthy gut environment in UC patients.

Prediction of antibiotic resistance mechanisms using a protein language model

MOTIVATION

Antibiotic resistance has emerged as a major global health threat, with an increasing number of bacterial infections becoming difficult to treat. Predicting the underlying resistance mechanisms of antibiotic resistance genes (ARGs) is crucial for understanding and combating this problem. However, existing methods struggle to accurately predict resistance mechanisms for ARGs with low similarity to known sequences and lack sufficient interpretability of the prediction models.

RESULTS

In this study, we present a novel approach for predicting ARG resistance mechanisms using ProteinBERT, a protein language model (pLM) based on deep learning. Our method outperforms state-of-the-art techniques on diverse ARG datasets, including those with low homology to the training data, highlighting its potential for predicting the resistance mechanisms of unknown ARGs. Attention analysis of the model reveals that it considers biologically relevant features, such as conserved amino acid residues and antibiotic target binding sites, when making predictions. These findings provide valuable insights into the molecular basis of antibiotic resistance and demonstrate the interpretability of pLMs, offering a new perspective on their application in bioinformatics.

AVAILABILITY AND IMPLEMENTATION

The source code is available for free at https://github.com/hmdlab/ARG-BERT. The output results of the model are published at https://waseda.box.com/v/ARG-BERT-suppl.

Dynamics of microbiome and resistome in a poultry burger processing line

Traditionally, surveillance programs for food products and food processing environments have focused on targeted pathogens and resistance genes. Recent advances in high throughput sequencing allow for more comprehensive and untargeted monitoring. This study assessed the microbiome and resistome in a poultry burger processing line using culturing techniques and whole metagenomic sequencing (WMS). Samples included meat, burgers, and expired burgers, and different work surfaces. Microbiome analysis revealed spoilage microorganisms as the main microbiota, with substantial shifts observed during the shelf-life period. Core microbiota of meat and burgers included Pseudomonas spp., Psychrobacter spp., Shewanella spp. and Brochothrix spp., while expired burgers were dominated by Latilactobacillus spp. and Leuconostoc spp. Cleaning and disinfection (C&D) procedures altered the microbial composition of work surfaces, which still harbored Hafnia spp. and Acinetobacter spp. after C&D. Resistome analysis showed a low overall abundance of resistance genes, suggesting that effective interventions during processing may mitigate their transmission. However, biocide resistance genes were frequently found, indicating potential biofilm formation or inefficient C&D protocols. This study demonstrates the utility of combining culturing techniques and WMS for comprehensive of the microbiome and resistome characterization in food processing lines.

Identification of key drivers of antimicrobial resistance in Enterococcus using machine learning

With antimicrobial resistance (AMR) rapidly evolving in pathogens, quick and accurate identification of genetic determinants of phenotypic resistance is essential for improving surveillance, stewardship, and clinical mitigation. Machine learning (ML) models show promise for AMR prediction in diagnostics but require a deep understanding of internal processes to use effectively. Our study utilised AMR gene, pangenomic, and predicted plasmid features from 647 Enterococcus faecium and Enterococcus faecalis genomes across the One Health continuum, along with corresponding resistance phenotypes, to develop interpretive ML classifiers. Vancomycin resistance could be predicted with 99% accuracy with AMR gene features, 98% with pangenome features, and 96% with plasmid clusters. Top pangenome features overlapped with the resistance genes of the vanA operon, which are often laterally transmitted via plasmids. Doxycycline resistance prediction achieved approximately 92% accuracy with pangenome features, with the top feature being elements of Tn916 conjugative transposon, a tet(M) carrier. Erythromycin resistance prediction models achieved about 90% accuracy, but top features were negatively correlated with resistance due to the confounding effect of population structure. This work demonstrates the importance of reviewing ML models' features to discern biological relevance even when achieving high-performance metrics. Our workflow offers the potential to propose hypotheses for experimental testing, enhancing the understanding of AMR mechanisms, which are crucial for combating the AMR crisis.

Exposure to doxycycline increases risk of carrying a broad range of enteric antimicrobial resistance determinants in an elderly cohort

OBJECTIVES

High rates of antibiotic prescription in residential aged care are likely to promote enteric carriage of antibiotic-resistant pathogens and increase the risk of antibiotic treatment failure. Despite their importance, relationships between antibiotic exposures and patterns of enteric resistance carriage in this population remain poorly understood.

METHODS

We conducted a cross-sectional metagenomic cohort analysis of stool samples from residents of five long-term aged-care facilities in South Australia. Taxonomic composition was determined, and enteric carriage of antibiotic resistance genes (ARGs) was identified and quantified against the Comprehensive Antibiotic Resistance Database. Both the detection and abundance of stool taxa and ARGs were related to antibiotic exposures up to 12 months prior. Factors associated with the abundance of ARGs of high clinical concern were identified.

RESULTS

Stool samples were provided by 164 participants (median age: 88 years, IQR 81-93; 72% female). Sixty-one percent (n = 100) of participants were prescribed antibiotics at least once in the prior 12 months (median prescriptions: 4, range: 1-52), most commonly a penicillin (n = 55, 33.5%), cephalosporin (n = 53, 32.3%), diaminopyrimidine (trimethoprim) (n = 36, 22%), or tetracycline (doxycycline) (n = 21, 12.8%). More than 1100 unique ARGs, conferring resistance to 38 antibiotic classes, were identified, including 20 ARGs of high clinical concern. Multivariate logistic regression showed doxycycline exposure to be the greatest risk factor for high ARG abundance (adjusted odds ratio [aOR]=14.8, q<0.001) and a significant contributor to inter-class selection, particularly for ARGs relating to penicillins (aOR=3.1, q=0.0004) and cephalosporins (aOR=3.4, q=0.003). High enteric ARG abundance was associated with the number of separate antibiotic exposures (aOR: 6.4, q<0.001), exposures within the prior 30 days (aOR: 4.6, q=0.008) and prior 30-100 days (aOR: 2.6, q=0.008), high duration of antibiotic exposure (aOR: 7.9, q<0.001), and exposure to 3 or more antibiotic classes (aOR: 7.4, q<0.001). Carriage of one or more ARGs of high clinical concern was identified in 99% of participants (n = 162, median: 3, IQR: 2-4), involving 11 ARGs conferring resistance to aminoglycosides, four to beta-lactams, one to glycopeptides, three to fluoroquinolones, and one to oxazolidinones. Carriage of ARGs of high clinical concern was positively associated with exposure to doxycycline (aminoglycoside, fluoroquinolone, and oxazolidinone ARGs) and trimethoprim (fluoroquinolone and beta-lactam ARGs). Analysis of doxycycline impact on microbiota composition suggested that observed resistome changes arose principally through direct ARG selection, rather than through the antibiotic depletion of sensitive bacterial populations.

CONCLUSIONS

The gut microbiome of aged care residents is a major reservoir of antibiotic resistance. As a critical antibiotic in medical practice, a comprehensive understanding of the impact of doxycycline exposure on the gut resistome is paramount for informed antibiotic use, particularly in an evolving landscape of prophylactic applications. Near-universal asymptomatic carriage of clinically critical resistance determinants is highly concerning and reinforces the urgent need for improved management of antibiotic use in long-term aged care.

The antibacterial activity and mechanisms of Trp-containing peptides against multidrug-resistant Pseudomonas aeruginosa persisters

Bacterial persisters avoid antibiotic-mediated death by entering a dormant state and are considered a major cause of antibiotic treatment failure. Antimicrobial peptides (AMPs) with membrane-disrupting activity are promising drugs to eradicate persister cells. In this study, carbonyl cyanide m-chlorophenylhydrazone (CCCP), ciprofloxacin (CIP), and rifampicin (RFP) were applied to induce the formation of multidrug-resistant Pseudomonas aeruginosa (MRPA0108) persisters, and the antibacterial activity and mechanisms of I1W and L12W (two Trp-containing peptides designed in our lab) against MRPA0108 persisters were investigated. The results showed that I1W and L12W displayed potent antibacterial activity against MRPA0108 persisters. Both Trp-containing peptides disturbed the inner and outer membrane of MRPA0108 persisters. In addition, I1W and L12W revealed novel antibacterial mechanisms by decreasing the enzymatic activities of superoxide dismutase (SOD) and catalase (CAT), increasing reactive oxygen species (ROS) and malondialdehyde (MDA) levels, consequently leading to oxidative stress. The transcriptome profile of I1W-treated MRPA0108 persisters revealed that the genes involved in carbon metabolism, biosynthesis of amino acids, and the TCA cycle were downregulated, indicating that I1W interfered with metabolism and energy synthesis processes. Furthermore, both Trp-containing peptides displayed synergistic activities with antibiotic tobramycin and showed additive activities with cefepime or ciprofloxacin, which revealed a potential therapeutic strategy for the eradication of MRPA0108 persisters.

Prediction of antimicrobial resistance in Klebsiella pneumoniae using genomic and metagenomic next-generation sequencing data

OBJECTIVES

Klebsiella pneumoniae is a significant pathogen with increasing resistance and high mortality rates. Conventional antibiotic susceptibility testing methods are time-consuming. Next-generation sequencing has shown promise for predicting antimicrobial resistance (AMR). This study aims to develop prediction models using whole-genome sequencing data and assess their feasibility with metagenomic next-generation sequencing data from clinical samples.

METHODS

On the basis of 4170 K. pneumoniae genomes, the main genetic characteristics associated with AMR were identified using a LASSO regression model. Consequently, the prediction model was established, validated and optimized using clinical isolate read simulation sequences. To evaluate the efficacy of the model, clinical specimens were collected.

RESULTS

Four predictive models for amikacin, ciprofloxacin, levofloxacin, and piperacillin/tazobactam, initially had positive predictive values (PPVs) of 92%, 98%, 99%, 94%, respectively, when they were originally constructed. When applied to clinical specimens, their PPVs were 96%, 96%, 95%, and 100%, respectively. Meanwhile, there were negative predictive values (NPVs) of 100% for ciprofloxacin and levofloxacin, and 'not applicable' (NA) for amikacin and piperacillin/tazobactam. Our method achieved antibacterial phenotype classification accuracy rates of 95.92% for amikacin, 96.15% for ciprofloxacin, 95.31% for levofloxacin and 100% for piperacillin/tazobactam. The sequence-based prediction antibiotic susceptibility testing (AST) reported results in an average time of 19.5 h, compared with the 67.9 h needed for culture-based AST, resulting in a significant reduction of 48.4 h.

CONCLUSIONS

These preliminary results demonstrated that the performance of prediction model for a clinically significant antimicrobial-species pair was comparable to that of phenotypic methods, thereby encouraging the expansion of sequence-based susceptibility prediction and its clinical validation and application.

Comparative genomic analysis of Acanthamoeba from different sources and horizontal transfer events of antimicrobial resistance genes

Acanthamoeba species are among the most common free-living amoeba and ubiquitous protozoa, mainly distributed in water and soil, and cause Acanthamoeba keratitis (AK) and severe visual impairment in patients. Although several studies have reported genomic characteristics of Acanthamoeba, limited sample sizes and sources have resulted in an incomplete understanding of the genetic diversity of Acanthamoeba from different sources. While endosymbionts exert a significant influence on the phenotypes of Acanthamoeba, including pathogenicity, virulence, and drug resistance, the species diversity and functional characterization remain largely unexplored. Herein, our study sequenced and analyzed the whole genomes of 19 Acanthamoeba pathogenic strains that cause AK, and by integrating publicly available genomes, we sampled 29 Acanthamoeba strains from ocular, environmental, and other sources. Combined pan-genomic and comparative functional analyses revealed genetic differences and evolutionary relationships among the different sources of Acanthamoeba, as well as classification into multiple functional groups, with ocular isolates in particular showing significant differences that may account for differences in pathogenicity. Phylogenetic and rhizome gene mosaic analyses of ocular Acanthamoeba strains suggested that genomic exchanges between Acanthamoeba and endosymbionts, particularly potential antimicrobial resistance genes trafficking including the adeF, amrA, and amrB genes exchange events, potentially contribute to Acanthamoeba drug resistance. In conclusion, this study elucidated the adaptation of Acanthamoeba to different ecological niches and the influence of gene exchange on the evolution of ocular Acanthamoeba genome, guiding the clinical diagnosis and treatment of AK and laying a theoretical groundwork for developing novel therapeutic approaches.

IMPORTANCE

Acanthamoeba causes a serious blinding keratopathy, Acanthamoeba keratitis, which is currently under-recognized by clinicians. In this study, we analyzed 48 strains of Acanthamoeba using a whole-genome approach, revealing differences in pathogenicity and function between strains of different origins. Horizontal transfer events of antimicrobial resistance genes can help provide guidance as potential biomarkers for the treatment of specific Acanthamoeba keratitis cases.

The curious case of the rare Citrobacter pasteurii isolated from an endangered primate in Brazil

The genus Citrobacter comprises clinically important human pathogens but has been less frequently associated with wildlife infections. Citrobacter pasteurii was first identified as causing human diarrhea and remains rarely documented. In this study, a Gram-negative bacterial strain, named A318, was identified as causing diarrhea in a black lion tamarin. This strain was biochemically identified as Trabulsiella guamensis, a species of unusual nature, and was submitted to whole-genome characterization. Curiously, phylogenomic analysis showed that A318 strain belonged to the genus Citrobacter, with confirmation of the species C. pasteurii by average nucleotide identity (99.02 %) and digital DNA-DNA hybridization (93.80 %) analyzes. Cases of misidentification of C. pasteurii as Citrobacter youngae were detected and corrected in this study. In addition to the genome sequence of the type strain of C. pasteurii, only two others from the Australian cockle and Portuguese silver gull are publicly available. Single nucleotide polymorphism differences among all C. pasteurii indicated a highly diverse population. No acquired antimicrobial resistance genes and plasmid replicons were found. Therefore, our findings emphasize the importance of gold-standard methods for accurate identification and underscores the importance of continued surveillance and research to mitigate the risks posed by zoonotic and zooanthroponotic pathogens.

Surveillance of travel-associated isolates elucidates the diversity of non-pandemic Vibrio cholerae

Vibrio cholerae is a Gram-negative bacterium found in aquatic environments and is the aetiological agent of cholera, characterized by acute watery diarrhoea and severe dehydration. Cholera presents a significant global health burden of an estimated 1.3-5 million annual cases, with the current pandemic caused by a toxigenic lineage of the O1 El Tor biotype called seventh pandemic El Tor (7PET) that is still ongoing. Whilst it is known that non-7PET lineages can cause sporadic disease, little is known about the transmission of these non-epidemic lineages. Thirty-four V. cholerae isolates were obtained from travellers returning from Indonesia to Australia between 2005 and 2017. These were whole genome sequenced, placed into a global phylogenetic context with 883 isolates, and screened for known genes associated with antimicrobial resistance and virulence. This analysis revealed that 30 isolates fell within non-7PET lineages and four within the 7PET lineage. Both 7PET and non-7PET isolates carried genes for resistance to antibiotics that are commonly used in cholera treatment such as tetracyclines and fluoroquinolones. Diverse virulence factors were also present in non-7PET isolates, with two isolates notably carrying toxin-coregulated pilus genes, which are primarily responsible for intestinal colonization in 7PET V. cholerae. This study demonstrates the role of travel in long-range carriage of epidemic and non-epidemic lineages of V. cholerae, and how sentinel travel surveillance can enrich our knowledge of V. cholerae diversity, reveal new biology about the spread of diverse lineages with differing disease potential and illuminate disease presence in endemic regions with limited surveillance data.

Identification of Corynebacterium ulcerans and Erysipelothrix sp. in Malayan pangolins-a potential threat to public health?

The discovery of severe acute respiratory syndrome-coronavirus-2-like and Middle East respiratory syndrome-coronavirus-like viruses in Malayan pangolins has raised concerns about their potential role in the spread of zoonotic diseases. Herein, we describe the isolation and whole-genome sequencing of potentially zoonotic two bacterial pathogens from diseased Malaysian pangolins (Manis javanica)-Corynebacterium ulcerans and Erysipelothrix sp. The newly identified species were designated as C. ulcerans P69 and Erysipelothrix sp. P66. C. ulcerans P69 exhibited 99.2% whole-genome nucleotide identity to human bacterial isolate 4940, suggesting that it might have zoonotic potential. Notably, C. ulcerans P69 lacked the diphtheria toxin (tox) gene that is widely used in vaccines to protect humans from corynebacterial infection, which suggests that the current vaccine may be of limited efficacy against this pangolin strain. C. ulcerans P69 also contains other known virulence-associated genes such as pld and exhibits resistance to several antibiotics (erythromycin, clindamycin, penicillin G, gentamicin, tetracycline), which may affect its effective control. Erysipelothrix sp. P66 was closely related to Erysipelothrix sp. strain 2-related strains, exhibiting 98.8% whole-genome nucleotide identity. This bacterium is lethal in mice, and two commercial vaccines failed to protect its challenge, such that it could potentially pose a threat to the swine industry. Overall, this study highlights that, in addition to viruses, pangolins harbor bacteria that may pose a potential threat to humans and domestic animals, and which merit attention.

IMPORTANCE

This study firstly reports the presence of two potentially zoonotic bacteria, Corynebacterium ulcerans and Erysipelothrix sp., in diseased Malaysian pangolins collected in 2019. The pangolin C. ulcerans is lethal in mice and resists many antibiotics. It clustered with a lethal human strain but lacked the diphtheria toxin gene. Diphtheria toxin is widely used as a vaccine around the world to protect humans from the infection of corynebacteria. The lack of the tox gene suggests that the current vaccine may be of limited efficacy against this pangolin strain. The pangolin Erysipelothrix sp. is the sister clade of Erysipelothrix rhusiopathiae. It is lethal in mice, and two commercial vaccines failed to protect the mice against challenge with the pangolin Erysipelothrix sp., such that this strain could potentially pose a threat to the swine industry. These findings emphasize the potential threat of pangolin bacteria.

A rapid microwave approach for 'one-pot' synthesis of antibiotic conjugated silver nanoparticles with antimicrobial activity against multi-drug resistant bacterial pathogens

Deaths directly attributable to drug-resistant infections reached 1.27 million in 2019 and continue to rise. This escalating resistance to antibiotics has driven a resurgence in the exploration of ancient antimicrobials to develop efficacious alternatives. The modern field of nanomaterials is a promising area of research with silver nanoparticles performing well as antimicrobial agents due to their large surface area and multiple bacterial targets. In the current study antibiotic conjugated silver nanoparticles (3-35 nm) were synthesized using β-lactam antibiotic, ampicillin. The method of heating during synthesis either microwave (4 min) or convection (4 h) influenced the physical characteristics of the ampicillin coated silver nanoparticles, however both approaches produced nanomaterials with antimicrobial activity against a variety of multi-drug resistant (MDR) clinical isolates in physiologically relevant media (when present at <0.2-2.28 mg L-1 in defined media). Critically, the microwave method is five times faster than the traditional water bath method, allowing rapid synthesis of ampicillin-conjugated nanoparticles, which supports scale up processes for industry. We suggest that the combination of antibiotic and silver in these nanoparticles produces a synergistic effect that circumvents resistance mechanisms and has the potential to provide a new line of combinatorial agents able to treat multi-drug resistant infections.

Towards geospatially-resolved public-health surveillance via wastewater sequencing

Wastewater is a geospatially- and temporally-linked microbial fingerprint of a given population, making it a potentially valuable tool for tracking public health across locales and time. Here, we integrate targeted and bulk RNA sequencing (N = 2238 samples) to track the viral, bacterial, and functional content over geospatially distinct areas within Miami Dade County, USA, from 2020-2022. We used targeted amplicon sequencing to track diverse SARS-CoV-2 variants across space and time, and we found a tight correspondence with positive PCR tests from University students and Miami-Dade hospital patients. Additionally, in bulk metatranscriptomic data, we demonstrate that the bacterial content of different wastewater sampling locations serving small population sizes can be used to detect putative, host-derived microorganisms that themselves have known associations with human health and diet. We also detect multiple enteric pathogens (e.g., Norovirus) and characterize viral diversity across sites. Moreover, we observed an enrichment of antimicrobial resistance genes (ARGs) in hospital wastewater; antibiotic-specific ARGs correlated to total prescriptions of those same antibiotics (e.g Ampicillin, Gentamicin). Overall, this effort lays the groundwork for systematic characterization of wastewater that can potentially influence public health decision-making.

Altered oral microbiota of drug-resistant organism carriers exhibit impaired gram-negative pathogen inhibition

The oral microbiome has been understudied as a reservoir for clinical pathogens, including drug-resistant strains. Understanding how alterations in microbiome functioning render this site vulnerable to colonization is essential, as multidrug-resistant organisms (MDRO) carriage is a major risk factor for developing serious infections. To advance our knowledge of oral MDRO carriage and protection against pathogen colonization conferred by native microbiota, we examined microbiomes from individuals colonized by MDROs (n=33) and non-colonized age-matched controls (n=30). Shotgun metagenomic analyses of oral swabs from study participants revealed significant differences in microbial communities with depletion of Streptococcus spp. among those colonized by multidrug-resistant gram-negative bacilli (RGNB), compared to non-carriers. We utilized metagenomic sequencing to characterize the oral resistome and find antimicrobial resistance genes are present in higher abundance among RNGB carriers versus non-carriers. High-throughput co-culture screening revealed oral bacteria isolated from MDRO non-carriers demonstrate greater inhibition of gram-negative pathogens, compared to isolates from carriers. Moreover, biosynthetic gene clusters from streptococci are found in higher abundance from non-carrier microbiomes, compared to RGNB carrier microbiomes. Bioactivity-guided fractionation of extracts from Streptococcus isolate SID2657 demonstrated evidence of strong E. coli and A. baumannii inhibition in a murine model of infection. Together, this provides evidence that oral microbiota shape this dynamic microbial community and may serve as an untapped source for much-needed antimicrobial small-molecules.

Screening of promising molecules against potential drug targets in Yersinia pestis by integrative pan and subtractive genomics, docking and simulation approach

This study focuses on Yersinia pestis, the bacterium responsible for plague, which posed a severe threat to public health in history. Despite the availability of antibiotics treatment, the emergence of antibiotic resistance in this pathogen has increased challenges of controlling the infections and plague outbreaks. The development of new drug targets and therapies is urgently needed. This research aims to identify novel protein targets from 28 Y. pestis strains by the integrative pan-genomic and subtractive genomics approach. Additionally, it seeks to screen out potential safe and effective alternative therapies against these targets via high-throughput virtual screening. Targets should lack homology to human, gut microbiota, and known human 'anti-targets', while should exhibit essentiality for pathogen's survival and virulence, druggability, antibiotic resistance, and broad spectrum across multiple pathogenic bacteria. We identified two promising targets: the aminotransferase class I/class II domain-containing protein and 3-oxoacyl-[acyl-carrier-protein] synthase 2. These proteins were modeled using AlphaFold2, validated through several structural analyses, and were subjected to molecular docking and ADMET analysis. Molecular dynamics simulations determined the stability of the ligand-target complexes, providing potential therapeutic options against Y. pestis.

Draft genome sequence of an arsenotrophic Achromobacter aegrifaciens strain isolated from soil in Bangladesh

We report the draft genome of an arsenotrophic Achromobacter aegrifaciens BAS32 isolated from arsenic (As)-contaminated soil in Bangladesh. This genome contains several predicted gene clusters for As-conversion, namely, As resistance (arsHCsO), arsenite-oxidizing (aioBA), and arsenate-reducing (arsRCDAB) gene clusters along with antibiotic resistance genes (ARGs).

Xenophilus aerolatus isolate misidentified as Brucella spp. by MALDI-TOF MS (VITEK-MS) system

We report the characterization of Xenophilus aerolatus strain identified from a screening rectal swab specimen in human, initially misidentified as Brucella spp. by MALDI-TOF MS (VITEK-MS system). The strain is able to growth on ColorexTM mSuperCARBA plate, suggesting carbapenem resistance. Whole genome sequencing identified several potential antimicrobial resistance mechanisms.

CC180 clade dynamics do not universally explain Streptococcus pneumoniae serotype 3 persistence post-vaccine: a global comparative population genomics study

Background Clonal complex 180 (CC180) is currently the major clone of serotype 3 Streptococcus pneumoniae (Spn). The 13-valent pneumococcal conjugate vaccine (PCV13) does not have significant efficacy against serotype 3 despite polysaccharide inclusion in the vaccine. It was hypothesized that PCV13 may effectively control Clade I of CC180 but that Clades III and IV are resistant, provoking a population shift that enables serotype 3 persistence. This has been observed in the United States, England, and Wales but not Spain. We tested this hypothesis further utilizing a dataset from Portugal. Methods We whole-genome sequenced (WGS) 501 serotype 3 strains from Portugal isolated from patients with pneumococcal infections between 1999-2020. The draft genomes underwent phylogenetic analyses, pangenome profiling, and a genome-wide association study (GWAS). We also completed antibiotic susceptibility testing and compiled over 2,600 serotype 3 multilocus sequence type 180 (MLST180) WGSs to perform global comparative genomics. Findings CC180 Clades I, II, III, IV, and VI distributions were similar when comparing non-invasive pneumonia isolates and invasive disease isolates (Fisher's exact test, P=0.29), and adult and pediatric cases (Fisher's exact test, P=0.074). The serotype 3 CCs shifted post-PCV13 (Fisher's exact test, P<0.0001) and Clade I became dominant. Clade I is largely antibiotic-sensitive and carries the phiOXC141 prophage but the pangenome is heterogenous. Strains from Portugal and Spain, where Clade I remains dominant post-PCV13, have larger pangenomes and are associated with the presence of two genes encoding hypothetical proteins. Interpretation Clade I became dominant in Portugal post-PCV13, despite the burden of the prophage and antibiotic sensitivity. The accessory genome content may mitigate these fitness costs. Regional differences in Clade I prevalence and pangenome heterogeneity suggest that clade dynamics is not a generalizable approach to understanding serotype 3 vaccine escape. Funding National Institute of Child Health and Human Development, Pfizer, and Merck Sharp & Dohme.

Investigation on the mechanisms of carbapenem resistance among the non-carbapenemase-producing carbapenem-resistant Klebsiella pneumoniae

Background

In Malaysia, an increase in non-carbapenemase-producing carbapenem-resistant Klebsiella pneumoniae (NC-CRKP) has been observed over the years. Previously, four NC-CRKP with increased susceptibility to ciprofloxacin in the presence of phenylalanine-arginine β-naphthylamide (PAβN) were identified. However, no contribution of the PAβN-inhibited efflux pump to carbapenem resistance was observed. All four NC-CRKP harboured non-carbapenemase β-lactamase, with two also exhibiting porin loss. In this study, we further investigated the genomic features and resistance mechanisms of these four isolates.

Methods

All four NC-CRKP were subjected to whole-genome sequencing, followed by comparative genomic and phylogenetic analyses.

Results

Multi-locus sequence typing (MLST) analysis divided the four NC-CRKP into different sequence types: ST392, ST45, ST14, and ST5947. Neither major nor rare carbapenemase genes were detected. Given the presence of non-carbapenemase β-lactamase in all isolates, we further investigated the potential mechanisms of resistance by identifying related chromosomal mutations. Deletion mutation was detected in the cation efflux system protein CusF. Insertion mutation was identified in the nickel/cobalt efflux protein RcnA. Missense mutation of ompK36 porin was detected in two isolates, while the loss of ompK36 porin was observed in another two isolates.

Conclusions

This study revealed that NC-CRKP may confer carbapenem resistance through a combination of non-carbapenemase β-lactamase and potential chromosomal mutations including missense mutation or loss of ompK36 porin and/or a frameshift missense mutation in efflux pump systems, such as cation efflux system protein CusF and nickel/cobalt efflux protein RcnA. Our findings highlighted the significance of implementing whole-genome sequencing into clinical practice to promote the surveillance of carbapenem resistance mechanisms among NC-CRKP.

Metagenomic Profiling of Internationally Sourced Sewage Influents and Effluents Yields Insight into Selecting Targets for Antibiotic Resistance Monitoring

It has been debated whether wastewater treatment plants (WWTPs) primarily act to attenuate or amplify antibiotic resistance genes (ARGs). However, ARGs are highly diverse with respect to their resistance mechanisms, mobilities, and taxonomic hosts and therefore their behavior in WWTPs should not be expected to be universally conserved. We applied metagenomic sequencing to wastewater influent and effluent samples from 12 international WWTPs to classify the behavior of specific ARGs entering and exiting WWTPs. In total, 1079 different ARGs originating from a variety of bacteria were detected. This included ARGs that could be mapped to assembled scaffolds corresponding to nine human pathogens. While the relative abundance (per 16S rRNA gene) of ARGs decreased during treatment at 11 of the 12 WWTPs sampled and absolute abundance (per mL) decreased at all 12 WWTPs, increases in relative abundance were observed for 40% of the ARGs detected at the 12th WWTP. Also, the relative abundance of mobile genetic elements (MGE) increased during treatment, but the fraction of ARGs known to be transmissible between species decreased, thus demonstrating that increased MGE prevalence may not be generally indicative of an increase in ARGs. A distinct conserved resistome was documented in both influent and effluent across samples, suggesting that well-functioning WWTPs generally attenuate influent antibiotic resistance loads. This work helps inform strategies for wastewater surveillance of antibiotic resistance, highlighting the utility of tracking ARGs as indicators of treatment performance and relative risk reduction.

Metagenomics reveals the potential transmission risk of resistomes from urban park environment to human

Urban parks play a significant role in urban ecosystems and are strongly associated with human health. Nevertheless, the biological contamination of urban parks - opportunistic pathogens and antibiotic resistance genes (ARGs) - has been poorly reported. Here, metagenomic and 16 S rRNA sequencing methods were used to study the distribution and assembly of opportunistic pathogens and ARGs in soil and water from nine parks in Lanzhou city, and further compared them with local human gut microbiomes to investigate the potential transmission risk. Our results revealed that the most important type of drug resistance in urban parks was multidrug resistance, with various resistance mechanisms. Approximately half of ARGs were shared between human gut and park environment, and it was noteworthy that cross-species transmission might exist among some high-risk ARGs, such as mepA and mdtE, with a significant enrichment in human gut. Metagenomic binning uncovered several bacterial genomes carrying adjacent ARGs, MGEs, and virulence genes, indicating a possibility that these genes may jointly transfer among different environments, particularly from park environment to human. Our results provided a reference point for the management of environmental pollutants in urban parks.

Easy analysis of bacterial whole-genome sequencing data for clinical microbiologists using open-source Galaxy platform: Characterization of ESBL-producing Enterobacterales from bloodstream infections

OBJECTIVES

Clinical microbiologists require easy-to-use open access tools with graphical interfaces to perform bacterial whole-genome sequencing (WGS) in routine practice. This study aimed to build a bioinformatics pipeline on the open-source Galaxy platform, facilitating comprehensive and reproducible analysis of bacterial WGS data in a few steps. We then used it to characterize our local epidemiology of ESBL-producing Enterobacterales isolated from patients with bacteremia.

METHODS

We built a bioinformatics pipeline consisting of the following sequential tools: Fastp (input data trimming); FastQC (read quality control); SPAdes (genome assembly); Quast (quality control of genome assembly); Prokka (gene annotation); Staramr (ResFinder database) and ABRicate (CARD database) for antimicrobial resistance (AMR) gene screening and molecular strain typing. Paired-end short read WGS data from all ESBL-producing Enterobacterales strains isolated from patients with bacteremia over one year were analysed.

RESULTS

The Galaxy platform does not require command line tools. The bioinformatics pipeline was constructed within one hour. It only required uploading fastq files and facilitated systematization of de novo assembly of genomes, MLST typing, and AMR gene screening in one step. Among the 66 ESBL-producing strains analysed, the two most frequent ESBL genes were blaCTX-M-15 (62.1%) and blaCTX-M-27 (13.6%).

CONCLUSIONS

The open-access Galaxy platform provides a graphical interface and easy-to-use tools suitable for routine use in clinical microbiology laboratories without bioinformatics specialists. We believe that this platform will facilitate fast and low-cost analysis of bacterial WGS data, especially in resource-limited settings.

In Vitro and In Vivo Studies on a Mononuclear Ruthenium Complex Reveals It is a Highly Effective, Fast-Acting, Broad-Spectrum Antimicrobial in Physiologically Relevant Conditions

The crystal structure of a previously reported antimicrobial RuII complex that targets bacterial DNA is presented. Studies utilizing clinical isolates of Gram-negative bacteria that cause catheter-associated urinary tract infection, (CA)UTI, in media that model urine and plasma reveal that good antimicrobial activity is maintained in all conditions tested. Experiments with a series of Staphylococcus aureus clinical isolates show that, unlike the majority of previously reported RuII-based antimicrobial leads, the compound retains its potent activity even in MRSA strains. Furthermore, experiments using bacteria in early exponential growth and at different pHs reveal that the compound also retains its activity across a range of conditions that are relevant to those encountered in clinical settings. Combinatorial studies involving cotreatment with conventional antibiotics or a previously reported analogous dinuclear RuII complex showed no antagonistic effects. In fact, although all combinations show distinct additive antibacterial activity, in one case, this effect approaches synergy. It was found that the Galleria Mellonella model organism infected with a multidrug resistant strain of the ESKAPE pathogen Acinetobacter baumannii could be successfully treated and totally cleared within 48 h after a single dose of the lead complex with no detectable deleterious effect to the host.

zol & fai: large-scale targeted detection and evolutionary investigation of gene clusters

Many universally and conditionally important genes are genomically aggregated within clusters. Here, we introduce fai and zol, which together enable large-scale comparative analysis of different types of gene clusters and mobile-genetic elements (MGEs), such as biosynthetic gene clusters (BGCs) or viruses. Fundamentally, they overcome a current bottleneck to reliably perform comprehensive orthology inference at large scale across broad taxonomic contexts and thousands of genomes. First, fai allows the identification of orthologous instances of a query gene cluster of interest amongst a database of target genomes. Subsequently, zol enables reliable, context-specific inference of ortholog groups for individual protein-encoding genes across gene cluster instances. In addition, zol performs functional annotation and computes a variety of evolutionary statistics for each inferred ortholog group. Importantly, in comparison to tools for visual exploration of homologous relationships between gene clusters, zol can scale to thousands of gene cluster instances and produce detailed reports that are easy to digest. To showcase fai and zol, we apply them for: (i) longitudinal tracking of a virus in metagenomes, (ii) discovering novel population-level genetic insights of two common BGCs in the fungal species Aspergillus flavus, and (iii) uncovering large-scale evolutionary trends of a virulence-associated gene cluster across thousands of genomes from a diverse bacterial genus.

Viral diversity within marine biofilms and interactions with corrosive microbes

In marine environments, a wide variety of microbes like bacteria, and archaea influence on the corrosion of materials. Viruses are widely distributed in biofilms among these microbes and may affect the corrosion process through interactions with key corrosive prokaryotes. However, understanding of the viral communities within biofilms and their interactions with corrosive microbes remains is limited. To improve this knowledge gap, 53 metagenomes were utilized to investigate the diversity of viruses within biofilms on 8 different materials and their interactions with corrosive microbes. Notably, the viruses within biofilms predominantly belonged to Caudoviricetes, and phylogenetic analysis of Caudoviricetes and protein-sharing networks with other environments revealed the presence of numerous novel viral clades in biofilms. The virus‒host linkages revealed a close association between viruses and corrosive microbes in biofilms. This means that viruses may modulate host corrosion-related metabolism through auxiliary metabolic genes. It was observed that the virus could enhance host resistance to metals and antibiotics via horizontal gene transfer. Interestingly, viruses could protect themselves from host antiviral systems through anti-defense systems. This study illustrates the diversity of viruses within biofilms formed on materials and the intricate interactions between viruses and corrosive microbes, showing the potential roles of viruses in corrosive biofilms.

Draft genome sequence of Ruoffia tabacinasalis isolated from a bovine nasal swab: a novel member of the bovine nasal microbiota

We report the isolation and draft genome sequence of Ruoffia tabacinasalis, a novel member of the bovine nasal microbiota. The genome, which is estimated to be 90.5% complete, is composed of one contig comprising 2,363,349 bp with a GC content of 36.66%.

Lactiplantibacillus argentoratensis AGMB00912 protects weaning mice from ETEC infection and enhances gut health

Maintaining a healthy intestinal environment, optimal epithelial barrier integrity, and balanced gut microbiota composition are essential for the growth performance of weaning pigs. We identified Lactiplantibacillus argentoratensis AGMB00912 (LA) in healthy porcine feces as having antimicrobial activity against pathogens and enhanced short-chain fatty acid (SCFA) production. Herein, we assess the protective role of LA using a weaning mouse model with enterotoxigenic Escherichia coli (ETEC) infection. LA treatment improves feed intake and weight gain and alleviates colon shortening. Furthermore, LA inhibits intestinal damage, increases the small intestine villus height compared with the ETEC group, and enhances SCFA production. Using the Kyoto Encyclopedia of Genes and Genomes and other bioinformatic tools, including InterProScan and COGNIZER, we validated the presence of SCFA-producing pathways of LA and Lactiplantibacillus after whole genome sequencing. LA mitigates ETEC-induced shifts in the gut microbiota, decreasing the proportion of Escherichia and Enterococcus and increasing SCFA-producing bacteria, including Kineothrix, Lachnoclostridium, Roseuburia, Lacrimispora, Jutongia, and Blautia. Metabolic functional prediction analysis revealed enhanced functions linked to carbohydrate, amino acid, and vitamin biosynthesis, along with decreased functions associated with infectious bacterial diseases compared to the ETEC group. LA mitigates the adverse effects of ETEC infection in weaning mice, enhances growth performance and intestinal integrity, rebalances gut microbiota, and promotes beneficial metabolic functions. These findings validate the functionality of LA in a small animal model, supporting its potential application in improving the health and growth performance of weaning pigs.

Genomic portraits of methicillin-resistant staphylococci (MRS) from food fish unveiled the genes associated with staphylococcal food poisoning (SFP), virulence and antimicrobial resistance

BACKGROUND

Characteristics of non-clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) especially from fishery environment are poorly understood. This research, in addition to comprehensive characterisation, sought to delineate the genetic relatedness between the MRSA strains originating from clinical as well as non-clinical settings. Out of 39 methicillin-resistant staphylococcal isolates from 197 fish samples, 6 (Three each of methicillin-resistant S. haemolyticus (MRSH) and MRSA) with distinct resistance profiles were selected for whole-genome sequencing. Using respective bioinformatics tools, MRSA genomes were comprehensively characterized for resistome, virulomes, molecular epidemiology and phylogenetic analysis. Simultaneously, MRSH genomes were specifically examined to characterize antimicrobial resistance genes (ARGs), owing to the fact that MRSH is often recognized as a reservoir for resistance determinants.

RESULTS

Three MRSA clones identified in this study include ST672-IVd/t13599 (sequence type-SCCmec type/spa type), ST88-V/t2526, and ST672-IVa/t1309. Though, the isolates were phenotypically vancomycin-sensitive, five of the six genomes carried vancomycin resistance genes including the VanT (VanG cluster) or VanY (VanM cluster). Among the three MRSA, only one harbored the gene encoding Panton-Valentine Leukocidin (PVL) toxin, while staphylococcal enterotoxin (SEs) genes such as sea and seb, associated with staphylococcal food poisoning were identified in two other MRSA. Genomes of MRSH carried a composite of type V staphylococcal cassette chromosome mec (SCCmec) elements (5C2 & 5). This finding may be explained by the inversion and recombination events that may facilitate the integration of type V elements to the SCC elements of S. aureus with a methicillin-susceptible phenotype. Phylogenetically, MRSA from a non-clinical setting displayed a considerable relatedness to that from clinical settings.

CONCLUSION

This study highlights the genetic diversity and resistance profiles of MRSA and MRSH, with non-clinical MRSA showing notable relatedness to clinical strains. Future research should explore resistance gene transfer mechanisms and environmental reservoirs to better manage MRSA spread.

Isolation, characterization, and potential application of Acinetobacter baumannii phages against extensively drug-resistant strains

One of the significant issues in treating bacterial infections is the increasing prevalence of extensively drug-resistant (XDR) strains of Acinetobacter baumannii. In the face of limited or no viable treatment options for extensively drug-resistant (XDR) bacteria, there is a renewed interest in utilizing bacteriophages as a treatment option. Three Acinetobacter phages (vB_AbaS_Ftm, vB_AbaS_Eva, and vB_AbaS_Gln) were identified from hospital sewage and analyzed for their morphology, host ranges, and their genome sequences were determined and annotated. These phages and vB_AbaS_SA1 were combined to form a phage cocktail. The antibacterial effects of this cocktail and its combinations with selected antimicrobial agents were evaluated against the XDR A. baumannii strains. The phages exhibited siphovirus morphology. Out of a total of 30 XDR A. baumannii isolates, 33% were sensitive to vB_AbaS_Ftm, 30% to vB_AbaS_Gln, and 16.66% to vB_AbaS_Eva. When these phages were combined with antibiotics, they demonstrated a synergistic effect. The genome sizes of vB_AbaS_Ftm, vB_AbaS_Eva, and vB_AbaS_Gln were 48487, 50174, and 50043 base pairs (bp), respectively, and showed high similarity. Phage cocktail, when combined with antibiotics, showed synergistic effects on extensively drug-resistant (XDR) strains of A. baumannii. However, the need for further study to fully understand the mechanisms of action and potential limitations of using these phages is highlighted.

Whole-genome sequencing of Helicobacter pylori isolates from Native American gastric biopsy specimens

Helicobacter pylori infection has been linked to gastrointestinal diseases including gastric cancer. High rates of H. pylori infection and gastric cancer have been reported in indigenous populations within the United States. We report whole-genome sequencing of three H. pylori isolates originating from Native American patients presenting with gastric disease.