Implants coating strategies for antibacterial treatment in fracture and defect models: A systematic review of animal studies.

Objective: Fracture-related infection (FRI) remains a major concern in orthopaedic trauma. Functionalizing implants with antibacterial coatings are a promising strategy in mitigating FRI. Numerous implant coatings have been reported but the preventive and therapeutic effects vary. This systematic review aimed to provide a comprehensive overview of current implant coating strategies to prevent and treat FRI in animal fracture and bone defect models. Methods: A literature search was performed in three databases: PubMed, Web of Science and Embase, with predetermined keywords and criteria up to 28 February 2023. Preclinical studies on implant coatings in animal fracture or defect models that assessed antibacterial and bone healing effects were included. Results: A total of 14 studies were included in this systematic review, seven of which used fracture models and seven used defect models. Passive coatings with bacteria adhesion resistance were investigated in two studies. Active coatings with bactericidal effects were investigated in 12 studies, four of which used metal ions including Ag+ and Cu2+; five studies used antibiotics including chlorhexidine, tigecycline, vancomycin, and gentamicin sulfate; and the other three studies used natural antibacterial materials including chitosan, antimicrobial peptides, and lysostaphin. Overall, these implant coatings exhibited promising efficacy in antibacterial effects and bone formation. Conclusion: Antibacterial coating strategies reduced bacterial infections in animal models and favored bone healing in vivo. Future studies of implant coatings should focus on optimal biocompatibility, antibacterial effects against multi-drug resistant bacteria and polymicrobial infections, and osseointegration and osteogenesis promotion especially in osteoporotic bone by constructing multi-functional coatings for FRI therapy. The translational potential of this paper: The clinical treatment of FRI is complex and challenging. This review summarizes novel orthopaedic implant coating strategies applied to FRI in preclinical studies, and offers a perspective on the future development of orthopaedic implant coatings, which can potentially contribute to alternative strategies in clinical practice.

Predicting hosts and cross-species transmission of Streptococcus agalactiae by interpretable machine learning.

BACKGROUND: Streptococcus agalactiae, commonly known as Group B Streptococcus (GBS), exhibits a broad host range, manifesting as both a beneficial commensal and an opportunistic pathogen across various species. In humans, it poses significant risks, causing neonatal sepsis and meningitis, along with severe infections in adults. Additionally, it impacts livestock by inducing mastitis in bovines and contributing to epidemic mortality in fish populations. Despite its wide host spectrum, the mechanisms enabling GBS to adapt to specific hosts remain inadequately elucidated. Therefore, the development of a rapid and accurate method differentiates GBS strains associated with particular animal hosts based on genome-wide information holds immense potential. Such a tool would not only bolster the identification and containment efforts during GBS outbreaks but also deepen our comprehension of the bacteria's host adaptations spanning humans, livestock, and other natural animal reservoirs. METHODS AND RESULTS: Here, we developed three machine learning models-random forest (RF), logistic regression (LR), and support vector machine (SVM) based on genome-wide mutation data. These models enabled precise prediction of the host origin of GBS, accurately distinguishing between human, bovine, fish, and pig hosts. Moreover, we conducted an interpretable machine learning using SHapley Additive exPlanations (SHAP) and variant annotation to uncover the most influential genomic features and associated genes for each host. Additionally, by meticulously examining misclassified samples, we gained valuable insights into the dynamics of host transmission and the potential for zoonotic infections. CONCLUSIONS: Our study underscores the effectiveness of random forest (RF) and logistic regression (LR) models based on mutation data for accurately predicting GBS host origins. Additionally, we identify the key features associated with each GBS host, thereby enhancing our understanding of the bacteria's host-specific adaptations.

Global epidemiology of asymptomatic colonisation of methicillin-resistant Staphylococcus aureus in the upper respiratory tract of young children: a systematic review and meta-analysis.

OBJECTIVE: To estimate the global prevalence of asymptomatic colonisation, and determine the associated risk factors, antibiotic resistance and genotypes of methicillin-resistant Staphylococcus aureus (MRSA) in the upper respiratory tract of young children. DESIGN: Four bibliometric databases were searched for publications between 2010 and 2022 according to the protocol registered in PROSPERO. Cross-sectional or cohort studies describing the prevalence of asymptomatic colonisation of S. aureus and MRSA in young children were included. Data extraction and analysis were carried out by two reviewers independently according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. Pooled prevalence was estimated using a random effects model. SETTING AND STUDIES: We included studies where children without respiratory tract infection or Staphylococcal infection were recruited from the community, children's institutions (ie, nurseries, kindergartens, daycare centres and preschools) and healthcare centre visits and assessed for asymptomatic colonisation with S. aureus and MRSA. MAIN OUTCOME MEASURES: The pooled prevalence of asymptomatic colonisation of S. aureus and MRSA of young children globally. RESULTS: In this systematic review and meta-analysis of 21 416 young children, the pooled global prevalence of asymptomatic S. aureus colonisation was 25.1% (95% CI 21.4 to 28.8) and MRSA colonisation was 3.4% (95% CI 2.8 to 4.1). The clones of MRSA strains included healthcare-associated MRSA, community-associated MRSA and livestock-associated MRSA. CONCLUSION: This study provides evidence of increased MRSA colonisation globally among young children, underlining the critical role of asymptomatic carriers in MRSA transmission and the need for control measures. PROSPERO REGISTRATION NUMBER: CRD 42022328385.

LOX-1 acts as an N6-methyladenosine-regulated receptor for Helicobacter pylori by binding to the bacterial catalase.

The role of N6-methyladenosine (m6A) modification of host mRNA during bacterial infection is unclear. Here, we show that Helicobacter pylori infection upregulates host m6A methylases and increases m6A levels in gastric epithelial cells. Reducing m6A methylase activity via hemizygotic deletion of methylase-encoding gene Mettl3 in mice, or via small interfering RNAs targeting m6A methylases, enhances H. pylori colonization. We identify LOX-1 mRNA as a key m6A-regulated target during H. pylori infection. m6A modification destabilizes LOX-1 mRNA and reduces LOX-1 protein levels. LOX-1 acts as a membrane receptor for H. pylori catalase and contributes to bacterial adhesion. Pharmacological inhibition of LOX-1, or genetic ablation of Lox-1, reduces H. pylori colonization. Moreover, deletion of the bacterial catalase gene decreases adhesion of H. pylori to human gastric sections. Our results indicate that m6A modification of host LOX-1 mRNA contributes to protection against H. pylori infection by downregulating LOX-1 and thus reducing H. pylori adhesion.

Storage stability of lysostaphin solution and its pulmonary delivery.

Methicillin-resistant Staphylococcus aureus (MRSA) has become a leading causative pathogen of nosocomial pneumonia with an alarming in-hospital mortality rate of 30%. Last resort antibiotic, vancomycin, has been increasingly used to treat MRSA infections, but the rapid emergence of vancomycin-resistant strains urges the development of alternative treatment strategies against MRSA-associated pneumonia. The bacteriolytic enzyme, lysostaphin, targeting the cell wall peptidoglycan of S. aureus, has been considered as a promising alternative for MRSA infections. Its proteinaceous nature is likely benefit from direct delivery to the lungs, but the challenges for successful pulmonary delivery of lysostaphin lying on a suitable inhalation device and a formulation with sufficient storage stability. In this study, the applicability of a vibrating mesh nebulizer (Aerogen Solo®) and a soft mist inhaler (Respimat®) was investigated. Both devices were capable of aerosolizing lysostaphin solution into inhalable droplets and caused minimum antibacterial activity loss. In addition, lysostaphin stabilized with phosphate-buffered saline and 0.1% Tween 80 was proved to have acceptable stability for at least 12 months when stored at 4 °C. These promising data encourage further clinical development of lysostaphin for management of MRSA-associated lung infections.

Long-Term Safety Outcomes of Fecal Microbiota Transplantation: Real-World Data Over 8 Years From the Hong Kong FMT Registry.

BACKGROUND AND AIMS: Prospective long-term real-world safety data after fecal microbiota transplantation (FMT) remain limited. We reported long-term outcomes of FMT from a population-based FMT registry in Hong Kong. METHODS: We recruited patients undergoing FMT for recurrent Clostridioides difficile infection (CDI) and non-CDI indications from clinical trials, from June 2013 to April 2022 in Hong Kong. We captured data on demographics, FMT indications and procedures, clinical outcomes and short- to long-term safety. New medical diagnoses were obtained from electronic medical records and independently adjudicated by clinicians. Long-term safety in patients with recurrent CDI was compared with a control group treated with antibiotics. RESULTS: Overall, 123 subjects (median age 53 years, range 13-90 years; 52.0% male) underwent 510 FMTs and were prospectively followed up for a median of 30.3 (range, 1-57.9) months. The most common indication for FMT was type 2 diabetes mellitus. The most common short-term adverse events within 1 month of FMT included diarrhea and abdominal pain. At long-term follow-up beyond 12 months, 16 patients reported 21 new-onset medical conditions confirmed by electronic medical records. All were adjudicated to be unlikely to be related to FMT. There was no new case of inflammatory bowel disease, irritable bowel syndrome, allergy, diabetes mellitus, or psychiatric disorder. In a subgroup of patients with recurrent CDI, FMT was associated with a significantly higher cumulative survival probability compared with matched control subjects. CONCLUSIONS: This prospective real-world data from Asia's first FMT registry demonstrated that FMT has an excellent long-term safety profile. The risk of developing new medical conditions beyond 12 months after FMT is low.

Vaccine value profile for Group B streptococcus.

Group B streptococcus (GBS) is a major global cause of neonatal meningitis, sepsis and pneumonia, with an estimated 91,000 infant deaths per year and an additional 46,000 stillbirths. GBS infection in pregnancy is also associated with adverse maternal outcomes and preterm births. As such, the World Health Organization (WHO) prioritised the development of a GBS vaccine suitable for use in pregnant women and use in LMICs, where the burden of disease is highest. Several GBS vaccines are in clinical development. The WHO Defeating Meningitis by 2030 has set a target of 2026 for vaccine licensure. This 'Vaccine Value Profile' (VVP) for GBS is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships and multi-lateral organizations, and in collaboration with stakeholders from the WHO regions of AFR, AMR, EUR, WPR. All contributors have extensive expertise on various elements of the GBS VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Molecular epidemiology of Streptococcus agalactiae in non-pregnant populations: a systematic review.

Streptococcus agalactiae (group B Streptococcus, GBS) has recently emerged as an important pathogen among adults. However, it is overlooked in this population, with all global efforts being directed towards its containment among pregnant women and neonates. This systematic review assessed the molecular epidemiology and compared how the lineages circulating among non-pregnant populations relate to those of pregnant and neonatal populations worldwide. A systematic search was performed across nine databases from 1 January 2000 up to and including 20 September 2021, with no language restrictions. The Joanna Briggs Institute (JBI) Prevalence Critical Appraisal Tool (PCAT) was used to assess the quality of included studies. The global population structure of GBS from the non-pregnant population was analysed using in silico typing and phylogenetic reconstruction tools. Twenty-four articles out of 13 509 retrieved across 9 databases were eligible. Most studies were conducted in the World Health Organization European region (12/24, 50 %), followed by the Western Pacific region (6/24, 25 %) and the Americas region (6/24, 25 %). Serotype V (23%, 2310/10240) and clonal complex (CC) 1 (29 %, 2157/7470) were the most frequent serotype and CC, respectively. The pilus island PI1 : PI2A combination (29 %, 3931/13751) was the most prevalent surface protein gene, while the tetracycline resistance tetM (55 %, 5892/10624) was the leading antibiotic resistance gene. This study highlights that, given the common serotype distribution identified among non-pregnant populations (V, III, Ia, Ib, II and IV), vaccines including these six serotypes will provide broad coverage. The study indicates advanced molecular epidemiology studies, especially in resource-constrained settings for evidence-based decisions. Finally, the study shows that considering all at-risk populations in an inclusive approach is essential to ensure the sustainable containment of GBS.

Dispersal history and bidirectional human-fish host switching of invasive, hypervirulent Streptococcus agalactiae sequence type 283.

Human group B Streptococcus (GBS) infections attributable to an invasive, hypervirulent sequence type (ST) 283 have been associated with freshwater fish consumption in Asia. The origin, geographic dispersion pathways and host transitions of GBS ST283 remain unresolved. We gather 328 ST283 isolate whole-genome sequences collected from humans and fish between 1998 and 2021, representing eleven countries across four continents. We apply Bayesian phylogeographic analyses to reconstruct the dispersal history of ST283 and combine ST283 phylogenies with genetic markers and host association to investigate host switching and the gain and loss of antimicrobial resistance and virulence factor genes. Initial dispersal within Asia followed ST283 emergence in the early 1980s, with Singapore, Thailand and Hong Kong observed as early transmission hubs. Subsequent intercontinental dispersal originating from Vietnam began in the decade commencing 2001, demonstrating ST283 holds potential to expand geographically. Furthermore, we observe bidirectional host switching, with the detection of more frequent human-to-fish than fish-to-human transitions, suggesting that sound wastewater management, hygiene and sanitation may help to interrupt chains of transmission between hosts. We also show that antimicrobial resistance and virulence factor genes were lost more frequently than gained across the evolutionary history of ST283. Our findings highlight the need for enhanced surveillance, clinical awareness, and targeted risk mitigation to limit transmission and reduce the impact of an emerging pathogen associated with a high-growth aquaculture industry.

Randomised clinical trial: Faecal microbiota transplantation for irritable bowel syndrome with diarrhoea.

BACKGROUND: Faecal microbiota transplantation (FMT) has been shown to improve symptoms in a proportion of patients with irritable bowel syndrome (IBS). AIM: We performed a randomised trial to assess the efficacy of FMT in patients with IBS. METHODS: We randomised 56 patients with diarrhoea-predominant IBS 1:1 to FMT or placebo via the duodenal route at baseline and week 4. The primary outcome was > 50 points decrease in IBS severity scoring system (IBS-SSS) score at week 12. Secondary outcomes were improvement in bloating and change in gut microbiota at week 12. After 12-week follow-up, those in the placebo group were assigned to receive open-label FMT. RESULTS: At week 12, 57.1% in the FMT group and 46.4% in the placebo group achieved the primary endpoint (p = 0.42). More patients receiving FMT than placebo had improvement in bloating (72% vs 30%; p = 0.005). In an open-label extension, 65.2% and 82.4% of patients achieved, respectively, the primary endpoint and improvement in bloating. Faecal microbiome of patients in the FMT group showed a reduction in bacteria like Ruminococcus gnavus and enrichment of bacteria such as Lawsonibacter at week 12, while no change in the placebo group. Functional analyses showed that the hydrogen sulphide-producing pathway decreased in patients who had FMT (p < 0.05) accompanied by a reduction in contributing bacteria. There were no serious adverse events related to FMT. CONCLUSION: FMT performed twice at an interval of four weeks did not significantly reduce IBS-SSS score. However, more patients had improvement in abdominal bloating, which was associated with a reduction in hydrogen sulphide-producing bacteria. (ClinicalTrials.gov NCT03125564).

Whole genomes from bacteria collected at diagnostic units around the world 2020.

The Two Weeks in the World research project has resulted in a dataset of 3087 clinically relevant bacterial genomes with pertaining metadata, collected from 59 diagnostic units in 35 countries around the world during 2020. A relational database is available with metadata and summary data from selected bioinformatic analysis, such as species prediction and identification of acquired resistance genes.

Trends in invasive bacterial diseases during the first 2 years of the COVID-19 pandemic: analyses of prospective surveillance data from 30 countries and territories in the IRIS Consortium.

BACKGROUND: The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic. METHODS: For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere. FINDINGS: Overall, 116 841 cases were analysed: 76 481 in 2018-19, before the pandemic, and 40 360 in 2020-21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40-0·55), H influenzae (0·51; 0·40-0·66) and N meningitidis (0·26; 0·21-0·31), while no significant changes were observed for S agalactiae (1·02; 0·75-1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145-55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories. INTERPRETATION: COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies. FUNDING: Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization.

Hydrogel delivery of DNase I and liposomal vancomycin to eradicate fracture-related methicillin-resistant staphylococcus aureus infection and support osteoporotic fracture healing.

Fracture-related infection (FRI) is a devastating complication in orthopedic surgery. A recent study showed that FRI causes more severe infection and further delays healing in osteoporotic bone. Moreover, bacterial biofilm formed on implants cannot be eradicated by systemic antibiotics, warranting novel treatments. Here, we developed a DNase I and Vancomycin hydrogel delivery vehicle to eradicate Methicillin-resistant Staphylococcus aureus (MRSA) infection in vivo. Vancomycin was encapsulated in liposomes, and DNase I and Vancomycin/liposomal-Vancomycin was loaded on thermosensitive hydrogel. In vitro drug release test showed a burst release of DNase I (77.2%) within 72 h and sustained release of Vancomycin (82.6%) up to day 14. The in vivo efficacy was evaluated in a clinically relevant ovariectomy (OVX) induced osteoporotic metaphyseal fracture model with MRSA infection, and a total of 120 Sprague Dawley rats were used. In the OVX with infection group, biofilm development caused a drastic inflammatory response, trabecular bone destruction, and non-union. In the DNase I and Vancomycin co-delivery hydrogel group (OVX-Inf-DVG), bacteria on bone and implant were eradicated. X-ray and micro-CT showed preservation of trabecular bone and bone union. HE staining showed the absence of inflammatory necrosis, and fracture healing was restored. The local elevation of TNF-α and IL-6 and increased number of osteoclasts were prevented in the OVX-Inf-DVG group. Our findings suggest that dual release of DNase I and Vancomycin initially followed by Vancomycin only later up to 14 days effectively eliminates MRSA infection, prevents biofilm development and provides a sterile environment to promote fracture healing in osteoporotic bone with FRI. STATEMENT OF SIGNIFICANCE: The biofilm on implants are difficult to eradicate, causing recurrent infection and non-union in fracture-related infection (FRI). Here we developed a hydrogel therapy with high in vivo efficacy to eliminate MRSA biofilm infection in a clinically-relevant FRI model in osteoporotic bone. By loading DNase I and vancomycin/liposomal-vancomycin on thermosensitive poly-(DL-lactic acidco-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA hydrogel, a dual release of DNase I and Vancomycin was achieved whilst preserving enzyme activity. In this model, the progressive development of infection caused a drastic inflammatory response, osteoclastogenesis, trabecular bone destruction, and non-union of fracture. These pathological changes were successfully prevented by the dual delivery of DNase I and vancomycin. Our findings provide a promising strategy for FRI in osteoporotic bone.

Carbapenem resistance among Gram-negative isolates collected from patients in ICU and non-ICU hospital wards in Hong Kong: SMART 2017-2020.

OBJECTIVES: The aim of this study was to estimate carbapenem resistance in Pseudomonas aeruginosa and Enterobacterales isolated from infected patients in intensive care unit (ICU) and non-ICU hospital wards in Hong Kong. METHODS: Isolates of Pseudomonas aeruginosa (ICU, n = 35; non-ICU, n = 264) and Enterobacterales (ICU, n = 129; non-ICU, n = 1390) were collected in four Hong Kong hospitals in 2017-2020. Clinical and Laboratory Standards Institute broth microdilution minimum inhibitory concentrations (MICs) were interpreted according to Clinical and Laboratory Standards Institute 2021 M100 breakpoints. ß-lactamase genes were identified in imipenem-, imipenem/relebactam-, and ceftolozane/tazobactam-nonsusceptible isolates. RESULTS: Ceftolozane/tazobactam demonstrated potent in vitro activity against both P. aeruginosa (ICU, 88.6%; non-ICU, 98.5%) and Enterobacterales (96.1%; 97.1%). Percent susceptible values for P. aeruginosa isolates from ICU and non-ICU patients, respectively, were as follows: meropenem (ICU, 74.3%; non-ICU, 84.1%) and imipenem (68.6%; 73.1%). Only 1 of 77 isolates tested for ß-lactamase genes carried a carbapenemase (VIM-2). Percent susceptible values for Enterobacterales isolates from ICU and non-ICU patients were as follows: meropenem (100%; 99.4%), ertapenem (100%; 98.0%), and imipenem (88.4%; 88.6%). A total of 62 Enterobacterales isolates were tested for ß-lactamase genes. Only three isolates carried a carbapenemase gene; two (both Escherichia coli) were metallo-ß-lactamase-positive (both NDM-5), and one (Klebsiella pneumoniae) was OXA-48-like-positive. CONCLUSIONS: Carbapenem-nonsusceptible isolates of P. aeruginosa were common (>15% of isolates). P. aeruginosa percent susceptible values for ceftolozane/tazobactam (97.3% susceptible overall) were ≥14% higher than those for carbapenems in both ICU and non-ICU isolates. Carbapenemases were rare among both P. aeruginosa (one isolate) and Enterobacterales (three isolates). Most Enterobacterales isolates tested from ICU and non-ICU patients in Hong Kong hospitals in 2017-2020 were susceptible to meropenem and ertapenem (≥98%); imipenem was less active (89% susceptible).

Alterations in faecal microbiome and resistome in Chinese international travellers: a metagenomic analysis.

BACKGROUND: International travel increases the risk of acquisition of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). Previous studies have characterized the changes in the gut microbiome and resistome of Western travellers; however, information on non-Western populations and the effects of travel-related risk factors on the gut microbiome and resistome remains limited. METHODS: We conducted a prospective observational study on a cohort of 90 healthy Chinese adult residents of Hong Kong. We characterized the microbiome and resistome in stools collected from the subjects before and after travelling to diverse international locations using shotgun metagenomic sequencing and examined their associations with travel-related variables. RESULTS: Our results showed that travel neither significantly changed the taxonomic composition of the faecal microbiota nor altered the alpha (Shannon) or beta diversity of the faecal microbiome or resistome. However, travel significantly increased the number of ARGs. Ten ARGs, including aadA, TEM, mgrB, mphA, qnrS9 and tetR, were significantly enriched in relative abundance after travel, eight of which were detected in metagenomic bins belonging to Escherichia/Shigella flexneri in the post-trip samples. In sum, 30 ARGs significantly increased in prevalence after travel, with the largest changes observed in tetD and a few qnrS variants (qnrS9, qnrS and qnrS8). We found that travel to low- or middle-income countries, or Africa or Southeast Asia, increased the number of ARG subtypes, whereas travel to low- or middle-income countries and the use of alcohol-based hand sanitizer (ABHS) or doxycycline as antimalarial prophylaxis during travel resulted in increased changes in the beta diversity of the faecal resistome. CONCLUSIONS: Our study highlights travel to low- or middle-income countries, Africa or Southeast Asia, a long travel duration, or the use of ABHS or doxycycline as antimalarial prophylaxis as important risk factors for the acquisition/enrichment of ARGs during international travel.

Enhancing Antibiotics Efficacy by Combination of Kuraridin and Epicatechin Gallate with Antimicrobials against Methicillin-Resistant Staphylococcus aureus.

BACKGROUND: Staphylococcus aureus is an opportunistic pathogen and a major cause of nosocomial and community-acquired infections. The alarming rise in Methicillin-resistant S. aureus (MRSA) infection worldwide and the emergence of vancomycin-resistant MRSA strains have created an urgent need to identify new and alternative treatment options. Triple combinations of antimicrobials with different antimicrobial mechanisms may be a good choice to overcome antimicrobial resistance. METHODS: In this study, we combine two natural compounds: kuraridin from Sophora flavescens and epicatechin gallate (ECG) from Camellia sinensis (Green tea), which could provide the best synergy with antibiotics against a selected panel of laboratory MRSA with known resistant mechanisms and clinical community-associated (CA) and hospital-associated (HA) MRSA as well. RESULTS: The combined use of ECG and kuraridin was efficacious in inhibiting the growth of a panel of tested MRSA strains. The antibacterial activities of gentamicin, fusidic acid and vancomycin could be further enhanced by the addition of ECG and kuraridin. In time-kill study, when vancomycin (0.5 µg/mL) was combined with ECG (2 µg/mL) and kuraridin (2 µg/mL), a very strong bactericidal growth inhibition against 3 tested strains ATCC25923, MRSA ST30 and ST239 was observed from 2 to 24 h. ECG and kuraridin both possess anti-inflammatory activities in bacterial toxin-stimulated peripheral blood mononuclear cells by suppressing the production of inflammatory cytokines (IL-1ß, IL-6 and TNFα) and are non-cytotoxic. In a murine pneumonia model infected with ATCC25923, MRSA ST30 or ST239, the combined use of ECG and kuraridin with vancomycin could significantly reduce bacterial counts. CONCLUSIONS: The present findings reveal the potential of ECG and kuraridin combination as a non-toxic herbal and antibiotics combination for MRSA treatment with antibacterial and anti-inflammatory activities.

Extent of Oral-Gut Transmission of Bacterial and Fungal Microbiota in Healthy Chinese Adults.

Recent studies have provided evidence on the presence of an oral-gut microbiota axis in gastrointestinal diseases; however, whether a similar axis exists in healthy individuals is still in debate. Here, we characterized the bacterial and fungal microbiomes in paired oral rinse and stool samples collected from 470 healthy Chinese adults by sequencing the 16S rRNA V3-V4 and ITS1 regions, respectively. We hypothesized that there is limited oral-gut transmission of both the bacterial and fungal microbiota in healthy Chinese adults. Our results showed that the oral and gut microbiota in healthy individuals differed in taxonomic composition, alpha and beta diversity, metabolic potential, and network properties. Bayesian analysis showed that the vast majority of subjects had negligible or low bacterial and fungal oral-to-stool contribution. Detailed examination of the prevalent amplicon sequence variants (ASVs) also revealed limited cases of sharing between the oral and stool samples within the same individuals, except a few bacterial and fungal ASVs. Association analysis showed that sharing of the potentially transmissible fungal ASVs was associated with host factors, including an older age and a higher body mass index. Our findings indicate that oral-gut transmission of both bacterial and fungal microbiota in healthy adults is limited. Detection of a large amount of shared bacterial or fungal members between the oral and gut microbiome of an individual may indicate medical conditions that warrant detailed checkup. IMPORTANCE The oral-gut microbiota axis in health is a fundamentally important and clinically relevant topic; however, our current understanding of it remains biased and incomplete. By characterizing the bacterial and fungal microbiomes in paired oral rinse and stool samples from a large cohort of healthy Chinese adults, here we provided new evidence that oral-gut microbiota transmission is limited in non-Western population and across biological domains. Our study has established an important baseline of a healthy oral-gut microbiota axis, with which other disease conditions can be compared. Besides, our findings have practical implications that detection of a large amount of shared bacterial or fungal members between the oral cavity and gut within the same individual as an indicator of potential medical conditions.

Rapid SARS-CoV-2 Variants Enzymatic Detection (SAVED) by CRISPR-Cas12a.

The continuous and rapid surge of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with high transmissibility and evading neutralization is alarming, necessitating expeditious detection of the variants concerned. Here, we report the development of rapid SARS-CoV-2 variants enzymatic detection (SAVED) based on CRISPR-Cas12a targeting of previously crucial variants, including Alpha, Beta, Gamma, Delta, Lambda, Mu, Kappa, and currently circulating variant of concern (VOC) Omicron and its subvariants BA.1, BA.2, BA.3, BA.4, and BA.5. SAVED is inexpensive (US$3.23 per reaction) and instrument-free. SAVED results can be read out by fluorescence reader and tube visualization under UV/blue light, and it is stable for 1 h, enabling high-throughput screening and point-of-care testing. We validated SAVED performance on clinical samples with 100% specificity in all samples and 100% sensitivity for the current pandemic Omicron variant samples having a threshold cycle (CT) value of ≤34.9. We utilized chimeric CRISPR RNA (crRNA) and short crRNA (15-nucleotide [nt] to 17-nt spacer) to achieve single nucleotide polymorphism (SNP) genotyping, which is necessary for variant differentiation and is a challenge to accomplish using CRISPR-Cas12a technology. We propose a scheme that can be used for discriminating variants effortlessly and allows for modifications to incorporate newer upcoming variants as the mutation site of these variants may reappear in future variants. IMPORTANCE Rapid differentiation and detection tests that can directly identify SARS-CoV-2 variants must be developed in order to meet the demands of public health or clinical decisions. This will allow for the prompt treatment or isolation of infected people and the implementation of various quarantine measures for those exposed. We report the development of the rapid SARS-CoV-2 variants enzymatic detection (SAVED) method based on CRISPR-Cas12a that targets previously significant variants like Alpha, Beta, Gamma, Delta, Lambda, Mu, and Kappa as well as the VOC Omicron and its subvariants BA.1, BA.2, BA.3, BA.4, and BA.5 that are currently circulating. SAVED uses no sophisticated instruments and is reasonably priced ($3.23 per reaction). As the mutation location of these variations may reoccur in subsequent variants, we offer a system that can be applied for variant discrimination with ease and allows for adjustments to integrate newer incoming variants.