Recent advances in the use of resveratrol against Staphylococcus aureus infections (Review).

As a notorious bacterial pathogen, Staphylococcus aureus (S. aureus) can readily induce infections in the community and hospital, causing significant morbidity and mortality. With the extensive rise of multiple resistance, conventional antibiotic therapy has rapidly become ineffective for related infections. Resveratrol is a naturally occurring polyphenolic substance that has been demonstrated to have effective antimicrobial activity against S. aureus. Resveratrol at sub-inhibitory doses can suppress the expression of virulence factors, contributing to attenuated biofilm formation, interference with quorum sensing and the inhibition of the production of toxins. As a promising efflux pump inhibitor, resveratrol enhances antibiotic susceptibility to a certain extent. In conjunction with conventional antibiotics, resveratrol displays unique synergistic effects with norfloxacin and aminoglycoside on S. aureus, yet antagonizes the lethal effects of daptomycin, oxacillin, moxifloxacin and levofloxacin. Nevertheless, given the low oral bioavailability of resveratrol, advanced formulations need to be developed to delay the rapid metabolism conversion to low or inactive conjugates. The present review discusses the antibacterial properties of resveratrol against S. aureus, in an aim to provide in-depth insight for researchers to address the challenges of antimicrobial resistance.

Advances in antibacterial activity of zinc oxide nanoparticles against Staphylococcus aureus (Review).

Nanoparticles (NPs) are one of the promising strategies to deal with bacterial infections. As the main subset of NPs, metal and metal oxide NPs show destructive power against bacteria by releasing metal ions, direct contact of cell membranes and antibiotic delivery. Recently, a number of researchers have focused on the antibacterial activity of zinc oxide nanoparticles (ZnO NPs) against Staphylococcus aureus (S. aureus). Currently, there is a lack of a comprehensive review on ZnO NPs against S. aureus. Therefore, in this review, the antibacterial activity against S. aureus of ZnO NPs made by various synthetic methods was summarized, particularly the green synthetic ZnO NPs. The synergistic antibacterial effect against S. aureus of ZnO NPs with antibiotics was also summarized. Furthermore, the present review also emphasized the enhanced activities against S. aureus of ZnO nanocomposites, nano-hybrids and functional ZnO NPs.

The longitudinal trend and influential factors exploring of global antimicrobial resistance in Klebsiella pneumoniae.

Klebsiella pneumoniae (Kp) is a human symbiotic opportunistic pathogen capable of causing severe hospital-based infections and community-acquired infections. The problem of antimicrobial resistance (AMR) has become increasing serious over time, posing a major threat to socio-economic and human development. In this study, we explored the global trend of AMR in 1786 strains of Kp isolated between 1982 and 2023. The number of antibiotic resistance genes (ARGs) in Kp increased significantly from 24.29 ± 5.44 to 32.42 ± 8.52 over time. Mobile genetic elements (MGEs) were responsible for the ARGs horizontal transfer of Kp strains. The results of structural equation modeling (SEM) indicated a strong association between the human development index and the increase of antibiotic consumption, which indirectly affected the occurrence and development of antibiotic resistance in Kp. The results of Generalized Linear Models (GLM) indicated that the influence of environmental factors such as temperature on the development of Kp resistance could not be ignored. Overall, this study monitored the longitudinal trend of antimicrobial resistance in Kp, explored the factors influencing antibiotic resistance, and provided insights for mitigating the threat of antimicrobial resistance.

The application of CRISPR-Cas system in Staphylococcus aureus infection.

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-CRISPR associated nuclease (Cas) system has been proven to play an irreplaceable role in bacteria immunity activity against exogenous genetic elements. In recent years, this system has emerged as a valid gene engineering method and could be used to detect and treat various microorganisms such as bacteria and viruses, etc. Staphylococcus aureus, as a Gram-positive, opportunistic human and animal pathogen, can cause a variety of diseases greatly threatening human health. Here, we mainly reviewed the applications of the CRISPR-Cas system in Staphylococcus aureus infections in detail. Furthermore, the prospects and drawbacks of the CRISPR-Cas system were also discussed.

Global epidemiology and genetic diversity of mcr-positive Klebsiella pneumoniae: A systematic review and genomic analysis.

The rapid increase of mcr-positive Klebsiella pneumoniae (K. pneumoniae) has received considerable attention and poses a major public health concern. Here, we systematically analyzed the global distribution of mcr-positive K. pneumoniae isolates based on published articles as well as publicly available genomes. Combining strain information from 78 articles and 673 K. pneumoniae genomes, a total of 1000 mcr-positive K. pneumoniae isolates were identified. We found that mcr-positive K. pneumoniae has disseminated widely worldwide, especially in Asia, with a higher diversity of sequence types (STs). These isolates were disseminated in 57 countries and were associated with 12 different hosts. Most of the isolates were found in China and were isolated from human sources. Moreover, MLST analysis showed that ST15 and ST11 accounted for the majority of mcr-positive K. pneumoniae, which deserve sustained attention in further surveillance programs. mcr-1 and mcr-9 were the dominant mcr variants in mcr-positive K. pneumoniae. Furthermore, a Genome-wide association study (GWAS) demonstrated that mcr-1- and mcr-9-producing genomes exhibited different antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), thereby indicating a distinct evolutionary path. Notably, the phylogenetic analysis suggested that certain mcr-positive K. pneumoniae genomes from various geographical areas and hosts harbored a high degree of genetic similarities (<20 SNPs), suggesting frequent cross-region and cross-host clonal transmission. Overall, our results emphasize the significance of monitoring and exploring the transmission and evolution of mcr-positive K. pneumoniae in the context of "One health".

Review on Long Non-Coding RNAs as Biomarkers and Potentially Therapeutic Targets for Bacterial Infections.

The confrontation between humans and bacteria is ongoing, with strategies for combating bacterial infections continually evolving. With the advancement of RNA sequencing technology, non-coding RNAs (ncRNAs) associated with bacterial infections have garnered significant attention. Recently, long ncRNAs (lncRNAs) have been identified as regulators of sterile inflammatory responses and cellular defense against live bacterial pathogens. They are involved in regulating host antimicrobial immunity in both the nucleus and cytoplasm. Increasing evidence indicates that lncRNAs are critical for the intricate interactions between host and pathogen during bacterial infections. This paper emphatically elaborates on the potential applications of lncRNAs in clinical hallmarks, cellular damage, immunity, virulence, and drug resistance in bacterial infections in greater detail. Additionally, we discuss the challenges and limitations of studying lncRNAs in the context of bacterial infections and highlight clear directions for this promising field.

Global distribution and genetic characterization of blaOXA-positive plasmids in Escherichia coli.

In recent years, the emergence of blaOXA-encoding Escherichia coli (E. coli) poses a significant threat to human health. Here, we systematically analyzed the global geographic distribution and genetic characteristics of 328 blaOXA-positive E. coli plasmids based on NCBI database. Twelve blaOXA variants have been discovered, with blaOXA-1 (57.93%) being the most common, followed by blaOXA-10 (11.28%) and blaOXA-48 (10.67%). Our results suggested that blaOXA-positive E. coli plasmids were widespread in 40 countries, mainly in China, the United States, and Spain. MLST analysis showed that ST2, ST43, and ST471 were the top three host STs for blaOXA-positive plasmids, deserving continuing attention in future surveillance program. Network analysis revealed a correlation between different blaOXA variants and specific antibiotic resistance genes, such as blaOXA-1 and aac (6')-Ib-cr (95.79%), blaOXA-181 and qnrS1 (87.88%). The frequent detection of aminoglycosides-, carbapenems- and even colistin-related resistance genes in blaOXA-positive plasmids highlights their multidrug-resistant potential. Additionally, blaOXA-positive plasmids were further divided into eight clades, clade I-VIII. Each clade displayed specificity in replicon types and conjugative transfer elements. Different blaOXA variants were associated with specific plasmid lineages, such as blaOXA-1 and IncFII plasmids in clade II, and blaOXA-48 and IncL plasmids in clade I. Overall, our findings provide a comprehensive insight into blaOXA-positive plasmids in E. coli, highlighting the role of plasmids in blaOXA dissemination in E. coli.

The Application of Rat Models in Staphylococcus aureus Infections.

Staphylococcus aureus (S. aureus) is a major human pathogen and can cause a wide range of diseases, including pneumonia, osteomyelitis, skin and soft tissue infections (SSTIs), endocarditis, mastitis, bacteremia, and so forth. Rats have been widely used in the field of infectious diseases due to their unique advantages, and the models of S. aureus infections have played a pivotal role in elucidating their pathogenic mechanisms and the effectiveness of therapeutic agents. This review outlined the current application of rat models in S. aureus infections and future prospects for rat models in infectious diseases caused by S. aureus.

Large-scale comparative analysis reveals phylogenomic preference of blaNDM-1 and blaKPC-2 transmission among Klebsiella pneumoniae.

blaNDM-1 and blaKPC-2 are responsible for the global increase in carbapenem-resistant Klebsiella pneumoniae, posing a great challenge to public health. However, the impact of phylogenetic factors on the dissemination of blaNDM-1 and blaKPC-2 is not yet fully understood. This study established a global dataset of 4051 blaNDM-1+ and 10,223 blaKPC-2+ K. pneumoniae genomes, and compared their transmission modes on a global scale. The results showed that blaNDM-1+ K. pneumoniae genomes exhibited a broader geographical distribution and higher sequence type (ST) richness than blaKPC-2+ genomes, indicating higher transmissibility of the blaNDM-1 gene. Furthermore, blaNDM-1+ genomes displayed significant differences in ST lineage, antibiotic resistance gene composition, virulence gene composition and genetic environments compared with blaKPC-2+ genomes, suggesting distinct dissemination mechanisms. blaNDM-1+ genomes were predominantly associated with ST147 and ST16, whereas blaKPC-2+ genomes were mainly found in ST11 and ST258. Significantly different accessory genes were identified between blaNDM-1+ and blaKPC-2+ genomes. The preference for blaKPC-2 distribution across certain countries, ST lineages and genetic environments underscores vertical spread as the primary mechanism driving the expansion of blaKPC-2. In contrast, blaNDM-1+ genomes did not display such a strong preference, confirming that the dissemination of blaNDM-1 mainly depends on horizontal gene transfer. Overall, this study demonstrates different phylogenetic drivers for the dissemination of blaNDM-1 and blaKPC-2, providing new insights into their global transmission dynamics.

Application of CRISPR-cas-based technology for the identification of tuberculosis, drug discovery and vaccine development.

Tuberculosis (TB), which caused by Mycobacterium tuberculosis, is the leading cause of death from a single infectious agent and continues to be a major public health burden for the global community. Despite being the only globally licenced prophylactic vaccine, Bacillus Calmette-Guérin (BCG) has multiple deficiencies, and effective diagnostic and therapeutic options are limited. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas (CRISPR-associated proteins) is an adaptive immune system that is found in bacteria and has great potential for the development of novel antituberculosis drugs and vaccines. In addition, CRISPR-Cas is currently recognized as a prospective tool for the development of therapies for TB infection with potential diagnostic and therapeutic value, and CRISPR-Cas may become a viable tool for eliminating TB in the future. Herein, we systematically summarize the current applications of CRISPR-Cas-based technology for TB detection and its potential roles in drug discovery and vaccine development.

Molecular mechanism of Hfq-dependent sRNA1039 and sRNA1600 regulating antibiotic resistance and virulence in Shigella sonnei.

Bacillary dysentery caused by Shigella spp. is a significant concern for human health. Small non-coding RNA (sRNA) plays a crucial role in regulating antibiotic resistance and virulence in Shigella spp. However, the specific mechanisms behind this phenomenon are still not fully understood. This study discovered two sRNAs (sRNA1039 and sRNA1600) that may be involved in bacterial resistance and virulence. By constructing deletion mutants (WT/ΔSR1039 and WT/ΔSR1600), this study found that the WT/ΔSR1039 mutants caused a two-fold increase in sensitivity to ampicillin, gentamicin and cefuroxime, and the WT/ΔSR1600 mutants caused a two-fold increase in sensitivity to cefuroxime. Furthermore, the WT/ΔSR1600 mutants caused a decrease in the adhesion and invasion of bacteria to HeLa cells (P<0.01), and changed the oxidative stress level of bacteria to reduce their survival rate (P<0.001). Subsequently, this study explored the molecular mechanisms by which sRNA1039 and sRNA1600 regulate antibiotic resistance and virulence. The deletion of sRNA1039 accelerated the degradation of target gene cfa mRNA and reduced its expression, thereby regulating the expression of pore protein gene ompD indirectly and negatively to increase bacterial sensitivity to ampicillin, gentamicin and cefuroxime. The inactivation of sRNA1600 reduced the formation of persister cells to reduce resistance to cefuroxime, and reduced the expression of type-III-secretion-system-related genes to reduce bacterial virulence by reducing the expression of target gene tomB. These results provide new insights into Hfq-sRNA-mRNA regulation of the resistance and virulence network of Shigella sonnei, which could potentially promote the development of more effective treatment strategies.

Characterization and diversity of CRISPR/Cas systems in Klebsiella oxytoca.

CRISPR (clustered regularly interspaced short palindromic repeats)/Cas (CRISPR-associated protein) system is a crucial adaptive immune system for bacteria to resist foreign DNA infection. In this study, we investigated the prevalence and diversity of CRISPR/Cas systems in 175 Klebsiella oxytoca (K. oxytoca) strains. Specifically, 58.86% (103/175) of these strains possessed at least one confirmed CRISPR locus. Two CRISPR/Cas system types, I-F and IV-A3, were identified in 69 strains. Type I-F system was the most prevalent in this species, which correlated well with MLST. Differently, type IV-A3 system was randomly distributed. Moreover, the type IV-A3 system was separated into two subgroups, with subgroup-specific cas genes and repeat sequences. In addition, spacer origin analysis revealed that approximately one-fifth of type I-F spacers and one-third of type IV-A3 spacers had a significant match to MGEs. The phage tail tape measure protein and conjunctive transfer system protein were important targets of type I-F and IV-A3 systems in K. oxytoca, respectively. PAM sequences were inferred to be 5'-NCC-3' for type I-F, 5'-AAG-3' for subgroup IV-A3-a, and 5'-AAN-3' for subgroup IV-A3-b. Collectively, our findings will shed light on the prevalence, diversity, and functional effects of the CRISPR/Cas system in K. oxytoca.

Analysis of the features of 105 confirmed CRISPR loci in 487 Klebsiella variicola.

Klebsiella variicola, an emerging human pathogen, poses a threat to public health. The horizontal gene transfer (HGT) of plasmids is an important driver of the emergence of multiple antibiotic-resistant K. variicola. Clustered regularly interspersed short palindromic repeats (CRISPR) coupled with CRISPR-associated genes (CRISPR/Cas) constitute an adaptive immune system in bacteria, and can provide acquired immunity against HGT. However, the information about the CRISPR/Cas system in K. variicola is still limited. In this study, 487 genomes of K. variicola obtained from the National Center for Biotechnology Information database were used to analyze the characteristics of CRISPR/Cas systems. Approximately 21.56% of genomes (105/487) harbor at least one confirmed CRISPR array. Three types of CRISPR/Cas systems, namely the type I-E, I-E*, and IV-A systems, were identified among 105 strains. Spacer origin analysis further revealed that approximately one-third of spacers significantly match plasmids or phages, which demonstrates the implication of CRISPR/Cas systems in controlling HGT. Moreover, spacers in K. variicola tend to target mobile genetic elements from K. pneumoniae. This finding provides new evidence of the interaction of K. variicola and K. pneumoniae during their evolution. Collectively, our results provide valuable insights into the role of CRISPR/Cas systems in K. variicola.

Mechanism of RNA m6 A methylation modification regulating NLRP3 inflammasome activation for hand, foot, and mouth disease progression.

Some children infected with hand, foot, and mouth disease (HFMD) caused by enterovirus 71 (EV71) progressed to severe disease with various neurological complications in the short term, with a poor prognosis and high mortality. Studies had revealed that RNA N6 -methyladenosine (m6 A) modification had a significant impact on EV71 replication, but it was unknown how m6 A modification regulated the host cell's innate immune response brought on by EV71 infection. We used MeRIP-seq (methylation RNA immunoprecipitation sequencing), RNA-seq (RNA sequencing), cell transfection, and other techniques. MeRIP-seq and RNA-seq results showed the m6 A methylation modification map of control and EV71-infected groups of RD cells. And multilevel validation indicated that decreased expression of demethylase FTO (fat mass and obesity-associated protein) was responsible for the elevated total m6 A modification levels in EV71-infected RD cells and that thioredoxin interacting protein (TXNIP) may be a target gene for demethylase FTO action. Further functional experiments showed that demethylase knockdown of FTO promoted TXNIP expression, activation of NLRP3 inflammasome and promoted the release of proinflammatory factors in vitro, and the opposite result occurred with demethylase FTO overexpression. And further tested in an animal model of EV71 infection in vitro, with results consistent with in vitro. Our findings elucidated that depletion of the demethylase FTO during EV71 infection increased the m6 A modification level of TXNIP mRNA 3' untranslated region (UTR), enhancing mRNA stability, and promoting TXNIP expression. Consequently, the NLRP3 inflammasome was stimulated, leading to the release of proinflammatory factors and facilitating HFMD progression.

Latest Advances in the Application of Humanized Mouse Model for Staphylococcus aureus.

Staphylococcus aureus (S. aureus) is an important pathogen for humans and can cause a wide range of diseases, from mild skin infections, severe osteomyelitis to fatal pneumonia, sepsis, and septicemia. The mouse models have greatly facilitated the development of S. aureus studies. However, due to the substantial differences in immune system between mice and humans, the conventional mouse studies are not predictive of success in humans, in which case humanized mice may overcome this limitation to some extent. Humanized mice can be used to study the human-specific virulence factors produced by S. aureus and the mechanisms by which S. aureus interacts with humans. This review outlined the latest advances in humanized mouse models used in S. aureus studies.

Transmission of livestock-associated methicillin-resistant Staphylococcus aureus between animals, environment, and humans in the farm.

Staphylococcus aureus (S. aureus) is a fearsome bacterial pathogen that can colonize and infect humans and animals. Depending on the different sources, MRSA is classified as hospital-associated methicillin-resistant S. aureus (HA-MRSA), community-associated MRSA (CA-MRSA), and livestock-associated MRSA (LA-MRSA). LA-MRSA is initially associated with livestock, and clonal complexes (CCs) were almost always 398. However, the continued development of animal husbandry, globalization, and the widespread use of antibiotics have increased the spread of LA-MRSA among humans, livestock, and the environment, and other clonal complexes such as CC9, CC5, and CC8 have gradually emerged in various countries. This may be due to frequent host switching between humans and animals, as well as between animals. Host-switching is typically followed by subsequent adaptation through acquisition and/or loss of mobile genetic elements (MGEs) such as phages, pathogenicity islands, and plasmids as well as further host-specific mutations allowing it to expand into new host populations. This review aimed to provide an overview of the transmission characteristics of S. aureus in humans, animals, and farm environments, and also to describe the main prevalent clones of LA-MRSA and the changes in MGEs during host switching.

A review on circular RNAs and bacterial infections.

Bacterial infections and related diseases have been a major burden on social public health and economic stability around the world. However, the effective diagnostic methods and therapeutic approaches to treat bacterial infections are still limited. As a group of non-coding RNA, circular RNAs (circRNAs) that were expressed specifically in host cells and played a key regulatory role have the potential to be of diagnostic and therapeutic values. In this review, we systematically summarize the role of circRNAs in common bacterial infections and their potential roles as diagnostic markers and therapeutic targets.

Involvement of RNA chaperone hfq in the regulation of antibiotic resistance and virulence in Shigella sonnei.

The host factor for RNA phage Qß replicase (Hfq) is a crucial post-transcriptional regulator in many bacterial pathogens, facilitating the interaction between small non-coding RNAs (sRNAs) and their target mRNAs. Studies have suggested that Hfq plays a role in antibiotic resistance and virulence in bacteria, although its functions in Shigella are not fully understood. In this study, we investigated the functional roles of Hfq in Shigella sonnei (S. sonnei) by constructing an hfq deletion mutant. Our phenotypic assays showed that the hfq deletion mutant was more sensitivity to antibiotics and had impaired virulence. Transcriptome analyses supported the results concerning the phenotype of the hfq mutant and showed that differentially expressed genes were mainly enriched in the KEGG pathways two-component system, ABC transporters, ribosome, and Escherichia coli biofilm formation. Additionally, we predicted eleven novel Hfq-dependent sRNAs, which were potentially involved in the regulation of antibiotic resistance and/or virulence in S. sonnei. Our findings suggest that Hfq plays a post-transcriptional role in regulating antibiotic resistance and virulence in S. sonnei, and could provide a basis for future studies on Hfq-sRNA-mRNA regulatory networks in this important pathogen.

Genomic Insights into CRISPR-Harboring Plasmids in the Klebsiella Genus: Distribution, Backbone Structures, Antibiotic Resistance, and Virulence Determinant Profiles.

CRISPR systems are often encoded by many prokaryotes as adaptive defense against mobile genetic elements (MGEs), but several MGEs also recruit CRISPR components to perform additional biological functions. Type IV-A systems are identified in Klebsiella plasmids, yet the distribution, characterization, and role of these plasmids carrying CRISPR systems in the whole Klebsiella genus remain unclear. Here, we performed large-scale comparative analysis of these plasmids using publicly available plasmid genomes. CRISPR-harboring plasmids were mainly distributed in Klebsiella pneumoniae (9.09%), covering 19.23% of sequence types, but sparse in Klebsiella species outside Klebsiella pneumoniae (3.92%). Plasmid genome comparison reiterated that these plasmids often carried the cointegrates of IncFIB and IncHI1B replicons, occasionally linked to other replicons, such as IncFIA, IncFII, IncR, IncQ, and IncU. Comparative genome analysis showed that CRISPR-carrying Klebsiella plasmids shared a conserved pNDM-MAR-like conjugation module as their backbones and served as an important vector for the accretion of antibiotic resistance genes (ARGs) and even virulence genes (VGs). Moreover, compared with CRISPR-negative IncFIB/IncHIB plasmids, CRISPR-positive IncFIB/IncHIB plasmids displayed high divergences in terms of ARGs, VGs, GC content, plasmid length, and backbone structures, suggesting their divergent evolutionary paths. The network analysis revealed that CRISPR-positive plasmids yielded fierce competitions with other plasmid types, especially conjugative plasmids, thereby affecting the dynamics of plasmid transmission. Overall, our study provides valuable insights into the role of CRISPR-positive plasmids in the spread of ARGs and VGs in Klebsiella genus.

Anxiety, depression, insomnia symptoms & associated factors among young to middle-aged adults during the resurgent epidemic of COVID-19: a cross-sectional study.

The coronavirus disease 2019 (COVID-19) pandemic is a public health emergency of international concern. However, its stress on the mental health of young to middle-aged adults is largely unexplored. This study aimed to evaluate the mental health difficulties during the resurgent phase of COVID-19 among young to middle-aged adults in China. There were 1,478 participants with a median age of 26 years (IQR, 23 - 30), including 535 males (36.2%). The prevalence of anxiety, depression, and insomnia were 8.6%, 11.4%, and 13.7%, respectively. Participants aged 29 - 59 years (OR, 95% CI: 2.46, 1.23 - 4.91) and females (2.49, 1.55 - 4.01) had a higher risk of anxiety. Education status, worried level about the current COVID-19, and the level of COVID-19's impact on life were significantly associated with the prevalence of anxiety. Besides, the level of COVID-19's impact on life was positively related to the prevalence of depression and insomnia. Our study provided novel evidence of psychological difficulties among young to middle-aged adults during the resurgent stage of the COVID-19 epidemic. Psychological intervention should be continuously implemented to prevent long-term psychological comorbidities during the COVID-19 epidemic.