Carbapenem-resistant (CRKP) and (CREC) are frequently detected in clinical settings, restricting the use of carbapenems. Therefore, there is an urgent need for new antimicrobial strategies to address infections caused by CRKP and CREC. This study investigated the antibacterial, anti-biofilm, and anti-inflammatory effects of the cationic antimicrobial peptide Hs02, along with its potential antimicrobial mechanisms against CRKP and CREC. The results revealed that Hs02 had a low minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against CRKP and CREC, effectively eliminating the bacteria within 30 min. Moreover, Hs02 significantly prevents biofilm formation and disrupts the established biofilms. Further mechanistic studies demonstrated that Hs02 specifically targeted and bound to bacterial outer membrane lipopolysaccharides (LPS), disrupted membrane permeability and integrity, which led to intracellular reactive oxygen species (ROS) accumulation. Furthermore, Hs02 neutralized LPS, thereby suppressing the production of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β in murine macrophage RAW 264.7 cells. , hemolysis and cytotoxicity assays confirmed Hs02's safety at the tested concentrations and proved that Hs02 improved the survival rate of larvae. In conclusion, the findings suggest that Hs02's interaction with LPS and the resulting disruption of membrane integrity may be key factors driving its rapid bactericidal and anti-inflammatory effects.

Reproducibility is a fundamental expectation in science and enables investigators to have confidence in their research findings and the ability to compare data from disparate sources, but evaluating reproducibility can be elusive. For example, generating RNA sequencing (RNA-seq) data includes multiple steps where variance can be introduced. Thus, it is unclear if RNA-seq data from different sources can be validly compared. While most studies on RNA-seq reproducibility focus on eukaryotes, we evaluate bias in bacteria using gene expression data from five laboratory models of cystic fibrosis. We leverage a large data set that includes samples prepared in three different laboratories and paired data sets where the same sample was sequenced using at least two different sequencing pipelines. We report here that expression data are highly reproducible across laboratories. In addition, while samples sequenced with different sequencing pipelines showed significantly more variance in expression profiles than between labs, gene expression was still highly reproducible between sequencing pipelines. Further investigation of expression differences between two sequencing pipelines revealed that library preparation methods were the largest source of error, though analyses to identify the source of this variance were inconclusive. Consistent with the reproducibility of expression between sequencing pipelines, we found that different pipelines detected over 80% of the same differentially expressed genes with large expression differences between conditions. Thus, bacterial RNA-seq data from different sources can be validly compared, facilitating the ability to advance understanding of bacterial behavior and physiology using the wide array of publicly available RNA-seq data sets.IMPORTANCERNA sequencing (RNA-seq) has revolutionized biology, but many steps in RNA-seq workflows can introduce variance, potentially compromising reproducibility. While reproducibility in RNA-seq has been thoroughly investigated in eukaryotes, less is known about pipelines and workflows that introduce variance and biases in bacterial RNA-seq data. By leveraging transcriptomes in cystic fibrosis models from different laboratories and sequenced with different sequencing pipelines, we directly assess sources of bacterial RNA-seq variance. RNA-seq data were highly reproducible, with the largest variance due to sequencing pipelines, specifically library preparation. Different sequencing pipelines detected overlapping differentially expressed genes, especially those with large expression differences between conditions. This study confirms that different approaches to preparing and sequencing bacterial RNA libraries capture comparable transcriptional profiles, supporting investigators' ability to leverage diverse RNA-seq data sets to advance their science.

The phyllosphere constitutes a critical habitat for microorganisms, exerting profound influences on host vitality, developmental dynamics, reproductive functions, and stress resilience. However, the diversity and network structure of endophytic and epiphytic fungal communities within this microecosystem have not been thoroughly explored. In this investigation, high-throughput sequencing technologies were employed to assess the diversity, community composition, and network structure of endophytic and epiphytic fungal communities associated with across six geographically distinct locations in Southeast China. The results revealed significant differences in community composition and diversity between endophytic and epiphytic fungi, with pronounced geographical variation observed within these phyllosphere fungal communities. Network analysis indicated that epiphytic fungal networks possess enhanced complexity compared with their endophytic counterparts, although the latter exhibit greater network stability. Moreover, stochastic processes were identified as pivotal in shaping the composition of these fungal communities. This research substantially enriches our comprehension of the diversity and organizational mechanisms of phyllosphere fungal communities, providing novel insights into the modalities of species coexistence and the stability of community equilibrium within ecosystems.IMPORTANCEThis study employs high-throughput sequencing technologies to explore the fungal communities within the phyllosphere of across Southeast China, offering significant insights into plant mycobiome. It demonstrates geographical variations in these fungal communities, with epiphytic fungi exhibiting more complex interaction networks compared with the endophytic fungi. Crucially, the research indicates that stochastic processes play a substantial role in the composition of fungal communities. These findings enhance our comprehension of plant-associated microecosystems and underscore the intricate interplay of randomness in maintaining ecosystem stability and diversity.

a Gram-negative facultative intracellular bacterium, is the etiological agent of cat-scratch disease and also causes bacillary angiomatosis in immunocompromised individuals. Although the ability to promote vascular endothelial cell proliferation differs among species, variations among strains within remain unclear. angiogenic factor A (BafA) and adhesin A (BadA) have been identified as autotransporters of that are involved in endothelial cell proliferation. Although strain-specific differences in the expression of BadA and the VirB/D4 type IV secretion system have been reported, BafA expression among strains has yet to be examined. Therefore, the present study investigated the proliferation-promoting ability of 13 strains from several sources in human umbilical vein endothelial cells (HUVECs). We identified BafA variants 1 and 2 based on the deduced amino acid sequences of its passenger domain. The recombinant proteins of both variants exhibited similar proliferation activity against HUVECs. However, BafA variant 2 strains showed cytotoxicity at a high bacterial inoculum in a direct coculture with HUVECs, which was attenuated in an indirect coculture. These strains, in contrast to BafA variant 1 strains, highly expressed BadA and exhibited bacterial aggregation. Based on a core genome SNP analysis of 50 strains, the BafA variant types corresponded to clades 1-4. These results indicate that vasoproliferative traits differ among clades based on the variant types. Therefore, this study provides a new conceptual framework in which the clades of may predict their pathogenicity in humans.IMPORTANCE species including , , and cause vasoproliferative lesions. Their proliferation-promoting ability in vascular endothelial cells differs among species; however, it is unclear whether these differences exist among strains. We herein showed that strains exhibited variable proliferation-promoting ability and cytotoxicity in vascular endothelial cells, which corresponded to the gene variants possessed by the strains. The expression levels of angiogenic factor A (BafA) and adhesin A, as well as the degree of proliferation-promoting ability and cytotoxicity in endothelial cells, varied among the strains. A core genome SNP analysis of strains using whole genome sequencing data divided strains into four clades, with each clade corresponding to BafA variants 1-4. These results suggest the differential vasoproliferative potency of , with potential implications in clinical management, including risk stratification and predictions of the clinical course.

Bloodstream infections (BSI) pose significant threats to patient health, necessitating timely and accurate diagnostics to reduce mortality and morbidity. This study aimed to evaluate the clinical performance of the BacT/ALERT VIRTUO blood culture system with FANPlus bottles compared to the BACTEC FX400 system in detecting bloodstream pathogens. A total of 1,772 blood specimens were collected from various hospital wards. Specimen selection criteria were based on clinical suspicion of bloodstream infections, ensuring the inclusion of relevant and representative patient samples. These blood samples, collected from the same suspected sepsis patients, were cultured in parallel using both the BacT/ALERT VIRTUO and BACTEC FX400 systems. The diagnostic efficiency of both systems, including detection rates, time to detection (TTD), and sensitivity across different bacterial species, was assessed. In various application scenarios, the VIRTUO system demonstrates a higher positive detection rate, whether in the intensive care unit (ICU) (8.5% vs 6.4%, = 0.028) or in general wards. Additionally, for different types of bacteria, the TVIRTUO system exhibits superior detection rates for anaerobic bacteria (5.9% vs 3.2%, < 0.001) and aerobic bacteria (9.1% vs 7.2%, = 0.043). Furthermore, it boasts a shorter median TTD of 14 hours compared to 16 hours, and a higher sensitivity for Gram-positive bacteria (2.8% vs 1.6%, < 0.001). These findings emphasize VIRTUO's effectiveness in enhancing diagnostic accuracy, achieving faster time to detection, and expanding the spectrum of detected organisms, thereby facilitating the quicker initiation of appropriate therapies, supporting precise clinical decision-making, and ultimately improving patient outcomes.IMPORTANCEOur study conducted a critical evaluation of advanced blood culture technologies for managing bloodstream infections (BSI). A distinctive strength of our research is the large sample size and the concurrent testing of the same patients with two systems, a methodology rarely achieved in other studies. BSIs present severe health threats, necessitating prompt and accurate diagnostics to mitigate morbidity and mortality. The BacT/ALERT VIRTUO system, in comparison to the BACTEC FX400 system, demonstrated superior detection capabilities, emphasizing the critical role of advanced diagnostics in clinical settings.

The occurrence of mastitis is mainly due to the infection of mammary tissue by pathogens, which causes the inflammation of mammary tissue. Gardenoside (GAD), an iridoid active ingredient extracted from , has been revealed to exhibit anti-inflammatory and anti-oxidative roles. However, the therapeutic effect of GAD on mastitis remains unclear. Our aim was to identify the therapeutic effect of GAD on )-induced mastitis and clarify its mechanism. To carry out this work, -induced mastitis of mice model was established. Enzyme-Linked Immunosorbent Assay (ELISA) was conducted to detect the production of Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). The biochemical method was used to detect the antioxidant factors glutathione (GSH), malondialdehyde (MDA), and iron content. Western blot was used to detect the expression of Nrf2/SLC7A11/GPX4 signal-related proteins. The results demonstrated that GAD alleviated Myeloperoxidase (MPO) activity, IL-1β and TNF-α production, and NF-κB activation. MDA and iron contents were also inhibited by GAD. Meanwhile, GSH level and GPX4, SLC7A11, and ferritin expressions were increased by GAD treatment. In addition, the expressions of Nrf2 and HO-1 were upregulated by GAD. In conclusion, GAP may inhibit -induced mastitis in mice by triggering the Nrf2/SLC7A11/GPX4 signaling pathway and alleviating inflammation and ferroptosis.

Multi-drug resistance (MDR) in continues to pose a significant public health challenge, particularly in developing countries. Recent advances in genomics strengthen the surveillance of MDR-pathogens and antimicrobial resistance (AMR) mediators. However, genome-based investigations into resistome dynamics in are limited, specifically in Bangladesh. Therefore, we investigated MDR- resistomes to evaluate their AMR transmission and phylodynamics. Clinical strains were screened for MDR phenotypes through susceptibility tests against 28 antibiotics from 10 different classes. Whole-genome sequencing (WGS) and bioinformatics approaches were performed to unveil the resistome dynamics: >500 global plasmid entities and >1,000 plasmid-mediated resistance gene clusters from global databases were included in this study. We identified 28 distinct antimicrobial resistance genes (ARGs) from nine antibiotic classes, with 75% originating from plasmids. Notably, two conjugative MDR plasmids included nearly all potential ARGs, conferring resistance to first-line drugs for shigellosis. Two third-generation cephalosporin-resistant [-ISEcp and ] and two macrolide-resistant mobile genomic islands (GIs) [-IS and -IS-IS] had emerged in in Bangladesh. In addition, trimethoprim-aminoglycoside-streptothricin-sulfonamide-resistant and were in conjugative plasmids in Bangladesh. The MDR plasmids and resistant GIs were phylogenetically relevant to Europe, USA, or China-derived isolates, indicating carry-over of the emerging ARGs from heavily industrialized countries and MSM-burdened (men who have sex with men) populations. The global burden of resistance GIs has increased sharply, especially after 2014. Emerging resistance mediators were most frequent (>80%) in human-associated and . We infer ARGs horizontally propagate among Enteropathogens: informing treatment strategies and supporting policymakers in strengthening AMR-containment efforts utilizing the phylodynamics network.IMPORTANCEThe world is suffering from a high burden of MDR enteropathogens. Healthcare providers in low- and middle-income countries (LMICs) often face trouble finding effective drugs among the many antibiotics introduced in diarrheal treatment. Resistance-mediated drug inactivation is more rapid than the advent of new antimicrobials, leaving enteritis treatment on the edge. In Bangladesh, where one-third of users are self-prescribing antibiotics and thousands are dying due to resistance-related treatment failure, phylogenomic evidence of AMR transmission root is scarce. Therefore, investigating the resistomes of MDR-, the leading cause of diarrheal deaths in Bangladesh, is crucial. We identified several emerging resistance mediators and their phylogenetic links to global entities, which is significant for improving shigellosis treatment and enhancing AMR containment strategies. Understanding the MDR mechanism in will help physicians choose effective drugs and anticipate resistance-mediated changes in treatment approaches; the spatiotemporal phylodynamics of AMR mediators aid policymakers in setting effective checkpoints in the AMR transmission network.

During microbial surveillance of the Mars 2020 spacecraft assembly facility, two novel bacterial strains, potentially capable of producing lasso peptides, were identified. Characterization using a polyphasic taxonomic approach, whole-genome sequencing and phylogenomic analyses revealed a close genetic relationship among two strains from Mars 2020 cleanroom floors (179-C4-2-HS, 179-J1A1-HS), one strain from the Agave plant (AT2.8), and another strain from wheat-associated soil (V4I25). All four strains exhibited high 16S rRNA gene sequence similarity (>99.2%) and low average nucleotide identity (ANI) with NBRC 15566, delineating new phylogenetic branches within the genus. Detailed molecular analyses, including B (90.2%), ANI (86.4%), average amino acid identity (87.8%) phylogenies, digital DNA-DNA hybridization (32.6%), and percentage of conserved proteins (77.7%) indicated significant divergence from NBRC 15566. Consequently, these strains have been designated sp. nov., with the type strain 179-C4-2-HS (DSM 115941 = NRRL B-65665). grew at 4°C to 45°C, pH range of 6.0 to 9.5, and 0.5% to 5% NaCl. The major cellular fatty acids are iso-C and anteiso-C. The dominant polar lipids include diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminolipid. Metagenomic analysis within NASA cleanrooms revealed that is scarce (17 out of 236 samples). Genes encoding the biosynthesis pathway for lasso peptides were identified in all strains and are not commonly found in other species, except in 7 out of 26 recognized species. This study highlights the unique metabolic capabilities of , underscoring their potential in antimicrobial research and biotechnology.

The colonization of in the female vagina leads to neonatal and pediatric enterococcal septicemia. Linezolid (LZD) is a kind of mainstream drug for treating multidrug-resistant Gram-positive infections. is the main LZD-resistance gene at in human isolates. It is essential to explore the prevalence of -carrying in vaginal secretions of late pregnant women and the drug resistance of . From May to June 2023, this study recruited 340 volunteers in late pregnancy (35-40 weeks of pregnancy) to provide non-repetitive vaginal discharge samples. Luria-Bertani broth and florfenicol (10 µg/mL) were used to enrich bacteria. was identified through time-of-flight mass spectrometry. Additionally, antimicrobial susceptibility, polymerase chain reaction, and next-generation sequencing assays were applied to this study. Fifty-four -carrying strains were obtained, the proportion of the whole vagina of late pregnant women was 15.88% (54 out of 340), and account the highest proportion. All -carrying were resistant to at least three drugs. Tetracycline, chloramphenicol, erythromycin, and LZD have higher bacterial resistance rates. Genetic environment analysis revealed that IS, , and (A) may synergistically exert multidrug resistance with . It is necessary to strengthen the surveillance of -carrying in pregnant women. This study provides scientific support for controlling hospital infections and managing antibiotic-resistant bacteria, and provides a scientific basis for rational clinical medication.IMPORTANCEThe disruption of cervicovaginal microbiota homeostasis is considered a key factor in causing imbalance in the microenvironment, leading to inflammation, transmission of infections, and illness. is considered a major cause of healthcare-related infections globally. It has resistance to multiple antimicrobial drugs, which pose significant challenges for clinical treatment. Therefore, it is crucial to assess the prevalence of -carrying in vaginal secretions of late pregnant women and the drug resistance of . This study detected 15.88% of -carried in 340 pregnant women. Furthermore, we found that -carrying strains are highly resistant to tetracycline, chloramphenicol, erythromycin, and Linezolid. Additionally, genetic environment analysis revealed that , , and (A) may synergistically exert multidrug resistance with . This study provides scientific support for controlling hospital infections and managing antibiotic-resistant bacteria and provides a scientific basis for rational clinical medication.

To discover new factors that are involved in iron acquisition by , we used RNA-Seq to identify the genes that are most highly induced when virulent strain 130b is cultured in a low-iron chemically defined medium. Among other things, this revealed , a heretofore uncharacterized gene that is predicted to be transcriptionally regulated by Fur and to encode a novel, ~15 kDa protein. was present in all strains examined and had homologs in a subset of the other species. Compatible with it containing a classic signal sequence, the 14915 protein was detected in bacterial culture supernatants in a manner dependent upon the type II secretion system. Thus, we designated 14915 as IrsA for on-egulated, ecreted protein . Based on mutant analysis, the gene was not required for optimal growth of strain 130b in low-iron media. However, after discovering that the commonly used laboratory-derived strain Lp02 has a much greater requirement for iron, we uncovered a growth-enhancing role for IrsA after examining an Lp02 mutant that lacked both IrsA and the Fe-transporter FeoB. The mutant of 130b, but not its complemented derivative, did, however, display increased biofilm formation on both plastic and agar surfaces, and compatible with this, the mutant hyper-aggregated. Thus, IrsA is a novel, iron-regulated exoprotein that modulates biofilm formation and, under some circumstances, promotes growth in low-iron conditions. For this study, we determined and deposited in the database a complete and fully assembled genome sequence for strain 130b.IMPORTANCEThe bacterium is the principal cause of Legionnaires' disease, a potentially fatal form of pneumonia that is increasing in incidence. exists in many natural and human-made water systems and can be transmitted to humans through inhalation of contaminated water droplets. flourishes within its habitats by spreading planktonically, assembling into biofilms, and growing in larger host cells. Iron acquisition is a key determinant for persistence in water and during infection. We previously demonstrated that assimilates iron both by secreting a non-protein iron chelator (siderophore) and by importing iron through membrane transporters. In this study, we uncovered a novel, secreted protein that is highly iron-regulated, promotes 's growth in low-iron media, and impacts biofilm formation. We also identified uncharacterized, IrsA-related proteins in other important human and animal pathogens. Thus, our results have important implications for understanding iron assimilation, biofilm formation, and pathogenesis.

is an emerging pathogen that causes life-threatening infections in neonates and immunocompromised patients. In this study, we performed next-generation sequencing (NGS) to characterize 10 strains isolated from clinical patients in Nantong, China. Core, accessory, and unique genomes were composed of 2,891, 1,633, and 498 genes, respectively. Based on genetic screening for antimicrobial resistance genes (AMRs), all strains carried the same AMRs, including , , and . The virulence factors (VFs) in the 10 strains were classified into 13 functional categories, and the differences between strains were mainly in immune modulation and nutritional/metabolic factor. We further analyzed the genomic features of one of ten strains, NT06 strain. The capsule type of NT06 was X, which is rare among strains. Based on comparative analyses, we first found that NT06 carried the YclNOPQ-like operon, which is the complete transporter for petrobactin, to acquire iron. The genomic features are important for further investigations of epidemiology, resistance, virulence, and to identify appropriate treatments.IMPORTANCE strains are opportunistic pathogens causing meningitis, bloodstream infections, and endophthalmitis in vulnerable populations. There is a lack of knowledge of the genetic diversity, presence of antimicrobial resistance genes (AMRs), and virulence factors (VFs) in isolated from clinical patient in China. Based on next-generation sequencing (NGS) and comparative genomic analyses, we determined the genomic features, phylogeny, and diversity of strains isolated from patients and identified a large accessory genome, intrinsic AMRs, and variable VFs. Based on comparative analyses, we identified a key strain, NT06, that carried a unique capsule type of X and the siderophore-mediated iron acquisition system (-like genes). These findings advance our understanding of the genomic plasticity, evolution, and pathogenicity determinants of .

Urinary tract infections (UTIs) are among the most prevalent infectious diseases, yet there is still limited understanding of the epidemiology of Enterococcal strains isolated from UTI patients in Shanghai. This study aims to elucidate the antimicrobial resistance profiles, virulence gene carriage, and molecular epidemiology of selected Enterococcal strains from UTI patients in Shanghai. A cohort of 80 and 40 clinical isolates were randomly selected from UTI patients from October 2022 to March 2023. No vancomycin-resistant strains were identified based on minimum inhibitory concentration (MIC) testing. However, five strains of linezolid-resistant were identified, all of which were confirmed to be -positive through whole-genome sequencing (WGS), with ST300 being reported as the first instance of this ST type in China. Polymerase chain reaction (PCR) assays were employed to ascertain the presence of virulence genes and multi-locus sequence type (MLST). In , the most common virulence genes were (75%), (65%), (52.5%), and (47.5%). In contrast, primarily exhibited (65%) and (12.5%). Among the strains, 21 distinct MLST types were identified, with ST16 and ST179 prevailing. Conversely, exhibited only five MLST types, with ST78 being predominant. The prevalence of CC16 and CC17 further complicates the treatment landscape for Enterococcal UTIs.

The rhizospheres of plants and soil microorganisms are intricately interconnected. Tea trees are cultivated extensively on the karst plateau of Guizhou Province, China; however, the understanding of the interactions among fungal communities, community taxa, and diseases impacting tea tree in the soil rhizosphere is limited. Our aim is to offer insights for the advancement of modern agriculture in ecologically fragile karst tea gardens, as well as microbiomics concepts for green and sustainable environmental development. This study utilized the internal transcribed spacer high-throughput sequencing technology to explore the symbiotic relationship between rhizosphere fungi and plant disease feedback in multiple tea estates across the Guizhou Plateau. The ecological preferences and environmental thresholds of fungi were investigated via environmental variables. Furthermore, a correlation was established between different taxa and individual soil functions. Research has indicated that tea leaf blight disrupts symbiotic connections among fungal groups. For various taxa, we found that numerous taxa consistently maintained core positions within the community, whereas rare taxa were able to stabilize due to a high proportion of positive effects. Additionally, abundant taxa presented a wider range of environmental feedback, whereas the rare taxon diversity presented a stronger positive association with the soil Z score. This study contributes to our understanding of the importance of rare taxa in plant rhizosphere soil processes. Emphasis should be placed on the role of rare taxa in pest and disease control within green agriculture while also strengthening systematic development and biogeographical research related to rare taxa in this region.IMPORTANCEIn this study, based on internal transcribed spacer high-throughput sequencing, fungal communities in the rhizosphere soil of tea trees and their interactions with the environment in karst areas were reported, and the symbiotic relationships of different fungal taxa and their feedback to the environment were described in detail by using the knowledge of microbial ecology. On this basis, it was found that tea tree diseases affect the symbiotic relationships of fungal taxa. At the same time, we found that rare taxa have stronger cooperative relationships in response to environmental changes and explored their participation in soil processes based on fungal trait sets. This study will provide basic data for the development of modern agriculture in tea gardens and theoretical basis for the sustainable prevention and control of tea tree diseases.

Murine models are commonly used to understand pathogen and host determinants of systemic infection. While these models have proven beneficial for uncovering bacterial mechanisms required for progression to invasive disease, it can be challenging to draw comparisons across studies as several different routes of infection are standardly used for these experiments. In this study, one of the leading bacterial meningeal pathogens, , or Group B (GBS), was used to compare experimental outcomes of two commonly used routes of hematogenous infection, lateral tail vein injection and retro-orbital venous sinus injection. Here we demonstrate that both routes of infection result in systemic disease and the onset of clinical symptoms of infection. We show that retro-orbital venous sinus injection results in an initial increase in bacterial dissemination to the spleen and brain tissue of GBS-infected mice, while an increased bacterial burden was only detected in brain tissues at a later time point. Despite differences in initial dissemination and brain bacterial burden, we found that the route of infection did not significantly impact bacterial burden in the blood, kidney, spleen, heart, and lung tissues at experimental endpoints; and similarly did not impact animal health scores during infection; cytokine and proinflammatory protein abundance in the brain tissue; or overall animal survival. In summary, these findings suggest that both tail vein injection and retro-orbital venous sinus injection are viable models to study Group B streptococcal systemic infection and result in largely similar disease outcomes within our tested parameters.

The aim of this study is to describe the genomic epidemiology of invasive Group A Streptococcus (iGAS) in Argentina during 2023. A total of 476 invasive GAS isolates were subtyped and analyzed by whole-genome sequencing. A high prevalence of the 1-type strain was observed. Among the 1 strains, two highly virulent international variants, 1-UK and 1-DK, were identified. Additionally, a local variant, called 1-ST1319, was detected. This seminal study provides initial insights into the genomic landscape of iGAS, contributing to active surveillance to monitor emerging virulent 1 lineages and cross-border transmission in South America.IMPORTANCEAmid the increase in invasive infections in Argentina in 2023, the implementation of genomic analysis of isolates allowed us to detect at the national level the prevalence of the 1 type and within the M1 type, emerging national and international hypervirulent lineages. These findings from our report shed light on the distribution of invasive Group A Streptococcus, laying the foundation for genomic surveillance of this pathogen.

Patients with hematological diseases are at high risk for (SM) bacteremia. This study retrospectively analyzed the clinical characteristics and risk factors for 28-day mortality among 140 adult hematological patients diagnosed with SM bacteremia from January 2012 to July 2023. he overall 28-day mortality was 31.43% (44/140), with a median age of 44 years. The median hospital stay before SM bacteremia onset was 25 days, and 69.29% of patients had unresolved neutropenia. All patients had received broad-spectrum antibiotics in the past month, and 69.29% developed breakthrough bacteremia during carbapenem therapy. Independent risk factors for mortality included a Sequential Organ Failure Assessment (SOFA) score ≥5, tigecycline exposure, age ≥60, and pulmonary infection. Patients with ≥2 risk factors were stratified into the high-risk group, with a significantly higher 28-day mortality compared with the low-risk group (56.52% vs 7.04%, < 0.001). Treatment with trimethoprim-sulfamethoxazole (TMP/SMX) ( = 0.008) or TMP/SMX combined with cefoperazone/sulbactam (CSL) ( = 0.005) was associated with survival benefits among high-risk patients. Overall, SM bacteremia usually occurs in hematological patients with prolonged hospitalization, unresolved neutropenia, and extensive use of broad-spectrum antibiotics, especially carbapenems. Patients with high SOFA scores, advanced age, pulmonary infection, or recent tigecycline exposure are at higher risk of mortality. The preferred treatment is TMP/SMX rather than fluoroquinolones, with combination therapy of TMP/SMX and CSL considered a feasible treatment option.IMPORTANCEThis study, representing the largest cohort of adult hematological patients with SM bacteremia to date, strengthens the validity of existing findings and provides new insights into its clinical management. We identify risk factors for 28-day mortality, revealing that patients with two or more risk factors experience particularly high mortality rates. This highlights the importance of early identification and targeted management of high-risk individuals. Our findings also demonstrate that TMP/SMX is superior to fluoroquinolones and suggest that combining TMP/SMX with CSL may offer additional survival benefits.

There is growing evidence that bacteria encountered in prosthetic joint infections (PJIs) form surface-attached biofilms on prostheses, as well as biofilm aggregates embedded in synovial fluid and tissues. However, models allowing the investigation of these biofilms and the assessment of their antimicrobial susceptibility in physiologically relevant conditions are currently lacking. To address this, we developed a synthetic synovial fluid (SSF2) model and validated this model by investigating growth, aggregate formation, and antimicrobial susceptibility using multiple PJI isolates belonging to various microorganisms. In this study, 18 PJI isolates were included belonging to , coagulase-negative staphylococci, , spp., spp., , , and spp. Growth and aggregate formation in SSF2 were evaluated using light microscopy and confocal laser scanning microscopy. The biofilm preventing concentration (BPC) and minimal biofilm inhibitory concentration (MBIC) of relevant antibiotics were determined using a resazurin-based viability staining. BPC and MBIC values were compared to conventional susceptibility parameters (minimal inhibitory concentration and minimal bactericidal concentration) determined with conventional approaches. The SSF2 medium allowed isolates to grow and form biofilm-like aggregates varying in size and shape between different species. For most isolates cultured in SSF2, a reduced susceptibility to the tested antibiotics was observed when compared to susceptibility data obtained in general media. These data indicate that the SSF2 model could be a valuable addition to evaluate the antimicrobial susceptibility of biofilm-like aggregates in the context of PJI.

Urease containing nickel cofactor is crucial for urea-hydrolytic induced calcium carbonate (CaCO) precipitation (UICP). However, limited information exists regarding the influence of amino acid residues interacting with nickel ions in its structure on induced CaCO mineralization. Herein, RT-qPCR was used to demonstrate that the addition of NiCl dramatically upregulated the expression of urease structural gene that was correlated with nickel binding in strain NS-6. Homology modeling and molecular docking were employed to construct the three-dimensional structure of urease and seek the key residues involved in nickel binding process, and virtual mutation technology was adopted to inform three key residues coordinated with nickel ions and urea, His249, His275, and Asp363. Four metrics, including root mean square deviation values for mutations of those key residues in urease-urea complexes severally and wild-type, were calculated by molecular dynamics simulations when they were mutated into alanine, respectively. Subsequently, the mutations of H249A, H275A, and D363A were characterized using western blotting to reveal a decrease in the relative expression and activity of urease, along with a corresponding reduction in CaCO precipitation. Ultimately, the mutations also exhibited that they had lower substrate affinity and catalytic efficiency for urea through enzymatic properties analysis. The findings suggested that those residues played a pivotal role in UICP of strain NS-6, which would expand the theoretical basis for modulating urease activity.IMPORTANCEUrease-producing bacterium is of great importance in diverse application fields, such as environmental remediation, due to its key driving characteristics in catalyzing urea hydrolysis via urea-hydrolytic induced CaCO precipitation (UICP). As essential cofactors of urease, nickel ions play a crucial role in regulating urease catalysis and maintaining structural stability. Numerous investigations have emphasized the impact of nickel ions on urease activity in recent years, to our best knowledge, only a few literatures have studied the molecular-level regulation of nickel-ligand residues. This study focused on the highly urease-producing bacterial NS-6 to explore the effects of specific nickel-ligand residues on the urease-aided CaCO mineralization process using molecular simulation predictions and targeted mutation experiments. The aim was to provide a molecular-level understanding of the interactive effects between urea and critical residues associated with the urease active center, as well as propose an effective modification strategy to enhance the application of UICP in future environmental areas.

The polysaccharide (PS) capsule of (pneumococcus) is the immunodominant surface structure that shields the bacteria from the host immune system. Since the capsule is the primary target of currently available pneumococcal vaccines, anti-capsular antibodies are highly protective but serotype-specific. Pneumococci may evade host or vaccine-induced immunity as a result of variation in capsule structure mediated via multiple mechanisms, such as the loss or gain of O-acetylation. Previous biochemical studies of serogroup 20 isolates have identified two subtypes-20A and 20B, whose capsule PS differs in the WhaF-mediated glucose side chain. Herein, we characterize a newly discovered capsule type, 20C, that differs from serotype 20B via the inactivation of capsule O-acetyltransferase gene, . Structural analysis demonstrated that 20C and 20B share an identical repeat unit [→3)-α-D-GlcNAc-[β-D-Gal-(1→4)][α-D-Glc-(1→6)]-(1→P→6)-α-D-Glc-(1→6)- β-D-Glc-(1→3)-β-D-Gal 5,6Ac-(1→3)-β-D-Glc-(1→], except for the absence of WciG-mediated Oacetyl group at terminal galactofuranose (β-D-Gal). We confirmed that deletion of the gene in a 20B strain resulted in the expression of the 20C capsule. Serotype 20C is serologically indistinguishable from the canonical 20A and 20B using conventional serotyping antibodies, but serogroup 20 subtypes can be distinguished by sequencing of genes-, , and . While genetic screening suggests 20C to be globally less prevalent, a new variant was identified which appears to have both and genes inactive, potentially indicating it to be a new serotype. Consequently, genome-based serotyping/bioinformatic tools must scrutinize all genes for mutations that might inactivate/modify -encoded enzymes, ensuring effective tracking of emerging capsule variants in response to ongoing vaccination efforts.

Plaque assay is the gold standard for the quantification of viable cytopathic viruses like Zika virus (ZIKV). Some strains of ZIKV produce plaques that are very difficult to accurately visualize and count on the commonly used Vero cell line. From data generated in our lab, we became curious if Vero/TMPRSS2 cells may be a better alternative; therefore, we compared the plaque forming units of two strains of ZIKV on Vero/TMPRSS2 cells to those produced by Vero cells. We also compared the virus stock titer generated on Vero/TMPRSS2 cells to that generated by the Vero cell line. Although the Vero cells generated higher quantity of ZIKV stocks, the Vero/TMPRSS2 cells produced plaques with significantly improved morphology and visibility and may, therefore, be a better alternative to use for performing plaque assays for strains of ZIKV that are more difficult to titer on regular Vero cells.

Fecal matter is recognized as both a reservoir and a transmission source for various antimicrobial resistance genes (AMRGs). However, the transcriptional activity of AMRGs in swine feces is not well understood. In addition, the effect of fecal microbiota transplantation (FMT) on the excretion of AMRGs has rarely been reported. Our study explored the diversity, abundance, transcriptional activity, and bacterial hosts of AMRGs in Tibetan and Duroc pig feces using metagenomic and metatranscriptomic sequencing technologies. We discovered a significantly higher genomic abundance of AMRGs in the feces of Duroc pigs compared to Tibetan pigs ( 0.001), although the transcript levels did not show a significant difference. The results showed that the core composition of AMRGs in pig feces varied considerably, with the most transcriptionally active AMRGs being , , , , and . Furthermore, the phylum is the main host of AMRGs. By transplanting fecal flora from Tibetan and Duroc pigs into the intestines of Duroc Landrace Yorkshire (DLY) piglets after acute antibiotic exposure, we found that only Tibetan pig fecal flora significantly reduced AMRGs in the feces of DLY piglets ( 0.05). The effectiveness of Tibetan pig fecal microorganisms in removing AMRGs from DLY pig feces was mainly influenced by microbial communities, especially the phylum. These findings offer valuable insights for the prevention and control of AMRG pollution.