The role of vaccines in preventing bacterial antimicrobial resistance

Elucidating Infectious Causes of Fever of Unknown Origin: A Laboratory-Based Observational Study of Patients with Suspected Ebola Virus Disease, Guinea, 2014

BACKGROUND

The etiology of fever of unknown origin (FUO) in sub-Saharan Africa often remains unexplained.

METHODS

We performed a retrospective laboratory-based observational study of 550 Guinean patients with FUO testing negative for Ebola virus from March to December 2014. Blood-borne pathogens were diagnosed by polymerase chain reaction (PCR) or reverse transcription-PCR (RT-PCR), serologic tests, and targeted and unbiased high-throughput sequencing (HTS).

RESULTS

In 275 of 550 individuals, we found evidence of ≥1 pathogen by molecular methods. We identified Plasmodium in 35.6% of patients via PCR, with P falciparum constituting 96.4% of these cases. Pathogenic bacteria, including Salmonella and Klebsiella, were detected in 18.4% of patients through PCR and HTS. Resistance determinants against first-line antibiotics were found in 26.9% of pooled sera by HTS. Yellow fever, Lassa, and Ebola viruses were detected in 5.8% of patients by RT-PCR; HTS-guided RT-PCR confirmed Orungo virus infection in 1 patient. Phylogenetic analyses revealed that the viral genomes matched the available genomic data in terms of location and time. Indirect immunofluorescence assays revealed immunoglobulin M antibodies against yellow fever, Ebola, dengue, West Nile, and Crimean Congo hemorrhagic fever viruses in 11 of 100 patients who were PCR or RT-PCR negative. One in 5 patients who were infected presented coinfections, predominantly malaria associated with sepsis-causing bacteria, in adults (12.1%) and children (12.5%), whereas viral coinfections were rare. Patients presented fever (74.7%), asthenia (67.7%), emesis (38.2%), diarrhea (28.3%), and hemorrhage (11.8%), without clear etiology associations.

CONCLUSIONS

An exhaustive laboratory investigation elucidated infectious causes of FUO in 52.3% of patients. Quality control and strengthening laboratory capacities in sub-Saharan Africa are essential for patient care, outbreak response, and regionally appropriate diagnostics.

Global burden of antimicrobial resistance in lower respiratory infections in 2021: A systematic analysis

OBJECTIVES

The research aimed to provide a worldwide evaluation of antimicrobial resistance (AMR), focusing specifically on AMR related to lower respiratory infections (LRI).

METHODS

The data were derived from the Global Antimicrobial Resistance Burden 2021 (GARB 2021). Two counterfactuals were utilized to estimate the deaths attributable to AMR and the deaths associated with AMR. The primary estimation process involved various statistical methodologies, including polynomial estimation and ensemble spatiotemporal Gaussian regression models. Using the DisMod-MR 2.1 modeling framework, the incidence and prevalence of LRI were estimated, the mortality rates were subsequently calculated, and stratified by pathogens, regions, and age groups. In addition, these indexes were identified and visualized to present global burden of AMR.

RESULTS

In 2021, there were 20.89 (95% uncertain interval: 18.27-23.50) deaths per 100 000 individuals associated with AMR in LRI, and 5.05 (95% UI: 4.29-5.51) deaths per 100 000 individuals attributable to AMR in LRI. Trimethoprim-sulfamethoxazole-resistant S. pneumoniae exhibited the highest mortality rate of 5.15 (95% UI: 3.96- 6.34) deaths per 100 000 individuals associated with AMR, while Carbapenem -resistant S. pneumoniae exhibited the highest mortality rate of 0.66 (95% UI: 0.45-0.86) deaths per 100 000 individuals attributable to AMR. S. pneumoniae exhibited the greatest burden of AMR, followed by S. aureus. Central Sub-Saharan Africa had the highest AMR burden, with mortality rates of 73.75 (95% UI: 56.61-90.89) deaths per 100 000 individuals associated with AMR and 17.73 (95% UI: 12.71-2.74) deaths per 100 000 individuals attributable to AMR, followed by Eastern Sub-Saharan Africa and Western Sub-Saharan Africa. The individuals aged under 5 and over 65 years exhibited high prevalence of antibiotic resistance especially to Carbapenems, Methicillin, and Fluoroquinolones.

CONCLUSION

AMR in the LRI is still a pressing global health issue, particularly in developing countries and neonatal age groups. Global interventions need to be taken to reduce the prevalence of AMR.

Unveiling the Group A Streptococcus Vaccine-Based L-Rhamnose from Backbone of Group A Carbohydrate: Current Insight Against Acute Rheumatic Fever to Reduce the Global Burden of Rheumatic Heart Disease

Group A Streptococcus (GAS) is a widely distributed bacterium that is Gram-positive and serves as the primary cause of acute rheumatic fever (ARF) episodes. Rheumatic heart disease (RHD) is a sequela resulting from repeated ARF attacks which are also caused by repeated GAS infections. ARF/RHD morbidity and mortality rates are incredibly high in low- and middle-income countries. This is closely related to poor levels of sanitation which causes the enhanced incidence of GAS infections. Management of carditis in RHD cases is quite challenging, particularly in developing countries, considering that medical treatment is only palliative, while definitive treatment often requires more invasive procedures with high costs. Preventive action through vaccination against GAS infection is one of the most effective steps as a solution in reducing RHD morbidity and mortality due to curative treatments are expensive. Various developments of M-protein-based GAS vaccines have been carried out over the last few decades and have recently begun to enter the clinical stage. Nevertheless, this vaccination generates cross-reactive antibodies that might trigger ARF assaults as a result of the resemblance between the M-protein structure and proteins found in many human tissues. Consequently, the development of a vaccine utilizing L-Rhamnose derived from the poly-rhamnose backbone of Group A Carbohydrate (GAC) commenced. The L-Rhamnose-based vaccine was chosen due to the absence of the Rhamnose biosynthesis pathway in mammalian cells including humans thus this molecule is not found in any body tissue. Recent pre-clinical studies reveal that L-Rhamnose-based vaccines provide a protective effect by increasing IgG antibody titers without causing cross-reactive antibodies in test animal tissue. These findings demonstrate that the L-Rhamnose-based vaccine possesses strong immunogenicity, which effectively protects against GAS infection while maintaining a significantly higher degree of safety.

NIAID Workshop Report: Systematic Approaches for ESKAPE Bacteria Antigen Discovery

On 14-15 November 2023, the National Institute of Allergy and Infectious Diseases (NIAID) organized a workshop entitled "Systematic Approaches for ESKAPE Bacteria Antigen Discovery". The goal of the workshop was to engage scientists from diverse relevant backgrounds to explore novel technologies that can be harnessed to identify and address current roadblocks impeding advances in antigen and vaccine discoveries for the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). The workshop consisted of four sessions that addressed ESKAPE infections, antigen discovery and vaccine efforts, and new technologies including systems immunology and vaccinology approaches. Each session was followed by a panel discussion. In total, there were over 260 in-person and virtual attendees, with high levels of engagement. This report provides a summary of the event and highlights challenges and opportunities in the field of ESKAPE vaccine discovery.

A new vaccination approach for Salmonellosis employing a multi-epitope vaccine based on live microbial cell factory from Lactococcus lactis

A major health and financial burden in the chicken sector is salmonella infection. It is difficult to create an oral vaccination that can provide strong intestinal mucosal immunity in birds, particularly cross-protection against several Salmonella serotypes. As a result, the poultry industry needs a powerful oral vaccination platform that uses live bacterial vectors to prevent various Salmonella serotypes. The genetically engineered L. lactis was given orally to birds as a vaccine after a multi-epitope vector was created using a reverse vaccinology technique. After the plasmid was digested, the target group produced a 72 kDa protein called multi-epitop. Birds that received the L. lactis/pNZ8121-Multi epitope vaccination showed increased levels of interferon (IFN-γ) and NFkB1α, increased transcription rates of cytokines, and a significant presence of IgY antibodies specific to the multi epitope gene in their serum. Salmonella infection is a severe health and economic burden in the poultry industry, according to spleen sections from the L. lactis/pNZ8121-Multi epitope. Developing an oral vaccine that can provide birds robust intestinal mucosal immunity-specifically, cross-protection against many Salmonella serotypes-is challenging. The results provide a fresh method for creating new immunological candidate multi-epitome genes by using the food-grade, non-pathogenic Lactococcus lactis as a protein cell factory. This method provides a unique technique to assess the long-term sustainability, cost, safety, and usefulness of experimental pharmaceutical products.

Recent Updates on Antibacterial Quinolones: Green Synthesis, Mode of Interaction and Structure-Activity Relationship

Quinolone antibiotics are a crucial class of synthetic antibacterial agents, widely utilized due to their broad spectrum of antibacterial activity. Due to the development of antimicrobial resistance, the potency of quinolone drugs decreased. Many conventional methods have been developed to elevate amination rate and to improve yield. These methods are generally characterized by prolonged reaction durations, high boiling solvents, harsh conditions, costly reagents and excessive heat generation, which have adversely affected the therapeutic efficacy of these compounds. Recently, green chemistry has focused on sustainable chemistry-dependent quinolone analogue synthesis methods that significantly reduce bacterial infections. These methods include one-pot synthesis, photoredox catalysis, phase transfer catalysis, ultrasonic irradiation, microwave-assisted, green solvent and catalyst-free synthesis, which often utilize energy-efficient, non-toxic and less time-consuming techniques, aligning with green chemistry principles to improve safety and environmental impact. Researchers continuously explore innovative approaches to applying these methods in synthetic reactions. This review includes a comprehensive analysis of synthetic literature from the past 15 years from Scopus, PubMed, Embase and WOS using keywords, such as green chemistry, quinolone and antibacterial, highlighting significant advancements and emerging trends. This work's importance lies in its extensive literature overview on green synthesis methods for quinolones and related heterocyclic compounds. Furthermore, to provide useful information for the generation of future antibacterial drugs, some structural-activity relationship studies and in silico studies have also been included to investigate the stable binding interactions between quinolone leads and various target proteins.

Quantitative fluorescent detection of tetracycline in animal-derived foods using quantum dots

Tetracycline (Tc) antibiotics, a class of synthetically produced broad-spectrum antimicrobial drugs, have been widely used in animal husbandry, leading to their widespread presence in animal-derived foods. However, misuse, overuse, and non-compliance with withdrawal periods in animal farming have resulted in excessive Tc residues in these foods, which can cause various adverse reactions in humans, induce bacterial resistance, and pose a significant threat to public health. Consequently, the detection of Tc antibiotic residues in animal-derived food has become a critical issue. This study aims to establish a novel method for quantifying Tc residues in animal-derived food using quantum dots (QDs) fluorescence immunoassay (FLISA). The developed method was optimized to achieve a detection limit of 0.69 ng/mL and a quantitative detection range of 1.30 ~ 59.22 ng/mL. The applicability of the method was demonstrated by successfully determining Tc residues in pork, chicken, fish, milk, eggs, and honey samples spiked with Tc standard solutions, yielding recoveries ranging from 94.01% to 110.19% and relative standard deviations between 1.10% and 11.39%. The significance of this study lies in its potential to provide a rapid and reliable approach for monitoring Tc residues in animal-derived food products, thereby contributing to the enhancement of food safety monitoring practices. KEY POINTS: • Screen out tetracycline-specific blocking monoclonal antibodies • The quantitative detection has high specificity and sensitivity • This method can be a useful tool for laboratories or testing facilities.

Vaccine uptake, associated factors and reasons for vaccination status among the South African elderly; findings and next steps

OBJECTIVES

The elderly are particularly prone to complications from a number of vaccine-preventable diseases. However, there are limited data on vaccine uptake for this vulnerable population in South Africa. Consequently, this study investigated influenza, pneumococcal and shingles vaccine uptake among elderly people in South Africa; reasons for their vaccination status; and factors associated with their uptake.

METHODS

Cross-sectional study using an interviewer-administered questionnaire to survey 985 consenting adults aged ≥65 years in 2018. Participants were recruited from across South Africa. Bivariate analysis was used to identify socio-demographic variables associated with vaccine uptake, with multivariate logistic regression analysis used to identify key factors associated with vaccine uptake.

RESULTS

Influenza vaccine uptake was 32.3% (318/985), with uptake highest in those aged 85-90 years. Pneumococcal and shingles vaccine uptake was 3.8% (37/985) and 0.4% (4/985) respectively, being highest among those aged >90 years. The strongest statistically significant predictors for influenza vaccination were previous influenza vaccination (OR: 8.42 [5.61-12.64]); identifying as 'Coloured' (OR: 8.39 [3.98-17.69]); and residing in Gauteng Province (OR: 5.44 [3.30-9.02]). The strongest statistically significant predictors of receiving pneumococcal vaccination included receiving influenza vaccination (OR = 10.67 [3.27-37.83]); residing in the Western Cape Province (OR: 7.34 [1.49-36.22]); identifying as 'Indian' (OR: 5.85 [2.53-13.55]); and having a university education (OR: 5.56 [1.25-24.77]). Statistically significant barriers to receiving influenza vaccination included following the Traditional African religion (OR: 0.08 [0.01-0.62]) and residing in Limpopo Province (OR: 0.16 [0.04-0.71]). The main reasons for non-vaccination were considering influenza as a mild illness (36.6%; 242/661), and lack of knowledge about the pneumococcal (93.4%; 886/948) and shingles (95.2%; 934/981) vaccines.

CONCLUSION

Vaccine uptake for all vaccines was sub-optimal, with multiple non-modifiable factors predicting vaccine uptake. These pre-COVID-19 data provide a baseline for measuring the effectiveness of future interventions to increase vaccine uptake and safeguard the health of the elderly.

The impact of vaccines for diarrhoea on antibiotic use among children in five low-resource settings: a comparative simulation study

BACKGROUND

Vaccines for diarrhoea could have the ancillary benefit of preventing antibiotic use. We aimed to quantify and compare the expected impact of enteric vaccines on antibiotic use via Monte Carlo simulations.

METHODS

We analysed data from a longitudinal birth cohort, which enrolled children from 2009 to 2012 from Bangladesh, India, Nepal, Pakistan, and Tanzania. We used Monte Carlo simulations to estimate hypothetical vaccine impact in nine vaccination scenarios (including six single vaccines and three combination vaccines) on antibiotic- treated diarrhoea, overall antibiotic courses, and antibiotic exposures to bystander pathogens. For each vaccine scenario, we randomly selected target pathogen-specific diarrhoea episodes to be prevented according to the specified vaccine efficacy and estimated the absolute and relative differences in incidence of antibiotic use outcomes between vaccine and no vaccine scenarios.

FINDINGS

Among 1119 children, there were 3029 (135·3 courses per 100 child-years) antibiotic-treated diarrhoea episodes. Based on simulated results, a Shigella vaccine would cause the greatest reductions compared with the other single pathogen vaccines in antibiotic courses for all-cause diarrhoea (6·1% relative reduction; -8·2 courses per 100 child-years [95% CI -9·4 to -7·2]), antibiotic courses overall (1·0% relative reduction; -8·2 courses per 100 child-years [-9·4 to -7·2]), and antibiotic exposures to bystander pathogens (1·2% relative reduction; -15·9 courses per 100 child-years [-18·5 to -13·8]). An adenovirus-norovirus-rotavirus vaccine would cause the greatest reductions in antibiotic use (12·2 courses per 100 child-years [-13·7 to -11·0]) compared with the other combination vaccines. However, projected vaccine effects on antibiotic use in 2021 were 45-74% smaller than those estimated in 2009-12 accounting for reductions in diarrhoea incidence in the past decade.

INTERPRETATION

Vaccines for enteric pathogens could result in up to 8-12 prevented courses of antibiotics per 100 vaccinated children per year. Combination vaccines will probably be necessary to achieve greater than 1% reductions in total antibiotic use among children in similar low-resource settings.

FUNDING

Wellcome Trust and Bill & Melinda Gates Foundation.

Excess burden of antibiotic-resistant bloodstream infections: evidence from a multicentre retrospective cohort study in Chile, 2018-2022

Background

Antibiotic-resistant bloodstream infections (ARB BSI) cause an enormous disease and economic burden. We assessed the impact of ARB BSI caused by high- and critical-priority pathogens in hospitalised Chilean patients compared to BSI caused by susceptible bacteria.

Methods

We conducted a retrospective cohort study from 2018 to 2022 in three Chilean hospitals and measured the association of ARB BSI with in-hospital mortality, length of hospitalisation (LOS), and intensive care unit (ICU) admission. We focused on BSI caused by Acinetobacter baumannii, Enterobacterales, Staphylococcus aureus, Enterococcus species, and Pseudomonas aeruginosa. We addressed confounding using propensity scores, inverse probability weighting, and multivariate regressions. We stratified by community- and hospital-acquired BSI and assessed total hospital and productivity costs.

Findings

We studied 1218 adult patients experiencing 1349 BSI episodes, with 47.3% attributed to ARB. Predominant pathogens were Staphylococcus aureus (33% Methicillin-resistant 'MRSA'), Enterobacterales (50% Carbapenem-resistant 'CRE'), and Pseudomonas aeruginosa (65% Carbapenem-resistant 'CRPA'). Approximately 80% of BSI were hospital-acquired. ARB was associated with extended LOS (incidence risk ratio IRR = 1.14, 95% CI = 1.05-1.24), increased ICU admissions (odds ratio OR = 1.25; 1.07-1.46), and higher mortality (OR = 1.42, 1.20-1.68) following index blood culture across all BSI episodes. In-hospital mortality risk, adjusted for time-varying and fixed confounders, was 1.35-fold higher (1.16-1.58) for ARB patients, with higher hazard ratios for hospital-acquired MRSA and CRE at 1.37 and 1.48, respectively. Using a societal perspective and a 5% discount rate, we estimated excess costs for ARB at $12,600 per patient, with an estimated annual excess burden of 2270 disability-adjusted life years (DALYs) and $9.6 (5.0-16.4) million.

Interpretation

It is urgent to develop and implement interventions to reduce the burden of ARB BSIs, particularly from MRSA and CRE.

Funding

Agencia Nacional de Investigación y Desarrollo ANID, Chile.

Tissue nano-transfection of antimicrobial genes drives bacterial biofilm killing in wounds and is potentially mediated by extracellular vesicles

The emergence of bacteria that are resistant to antibiotics is on track to become a major global health crisis. Therefore, there is an urgent need for new treatment options. Here, we studied the implementation of tissue-nanotransfection (TNT) to treat Staphylococcus aureus-infected wounds by delivering gene cargos that boost the levels of naturally produced antimicrobial peptides. The Cathelicidin Antimicrobial Peptide gene (CAMP), which produces the antimicrobial peptide LL-37, was used as model gene cargo. In vitro evaluation showed successful transfection and an increase in the transcription and translation of CAMP-coding plasmid in mouse primary epithelial cells. Moreover, we found that the extracellular vesicles (EVs) derived from the transfected cells (in vitro and in vivo) carried significantly higher concentrations of CAMP transcripts and LL-37 peptide compared to control EVs, possibly mediating the trafficking of the antimicrobial contents to other neighboring cells. The TNT platform was then used in vivo on an excisional wound model in mice to nanotransfect the CAMP-coding plasmid on the edge of infected wounds. After 4 days of daily treatment, we observed a significant decrease in the bacterial load in the CAMP-treated group compared to the sham group. Moreover, histological analysis and bacterial load quantification also revealed that TNT of CAMP on S. aureus-infected wounds was effective in treating biofilm progression by reducing the bacterial load. Lastly, we observed a significant increase in macrophage recruitment to the infected tissue, a robust increase in vascularization, as well as and an increased expression of IL10 and Fli1. Our results demonstrate that TNT-based delivery of gene cargos coding for antimicrobial compounds to the wound is a promising approach for combating biofilm infections in wounds.

mRNA-based platform for preventing and treating Staphylococcus aureus by targeted staphylococcal enterotoxin B

Staphylococcus aureus (S. aureus) possesses numerous virulence factors, with the increasing prevalence of drug-resistant strains heightening the threat posed by this pathogen. Staphylococcal enterotoxin B (SEB), a highly conserved toxin secreted by S. aureus, is also recognized as a potential bioweapon with super-antigenic activity. SEB represents a promising target in efforts to combat infections caused by S. aureus. We developed mRNA-based vaccine and antibody targeting SEB for both prophylactic and therapeutic purposes in varying S. aureus infection conditions. The mSEB mRNA vaccine (10 μg per mouse) induces more robust and persistent immune responses, including higher antibody titers and specific cellular immune responses, compared to immunization with 30 μg of mSEB protein adjuvanted with aluminum phosphate. Additionally, the anti-SEB mRNA antibody maintains secretion of anti-SEB monoclonal antibody (mAb) with a dosage that is 10 times lower than purified protein administration. The mRNA-based antibody exhibits superior pharmacokinetic profiles compared to its protein counterparts, efficiently neutralizing SEB and clearing S. aureus from circulation. Both the mRNA vaccine and mRNA antibody demonstrate preventive and therapeutic effects by eliciting specific immune responses and generating high-affinity antibodies in mice. We have laid the groundwork for the development and evaluation of mRNA-based vaccines and antibodies targeting SEB produced by S. aureus. Our studies demonstrate that these approaches are more effective than traditional protein-based vaccines and antibodies in terms of inducing immune responses, pharmacokinetics, and their prophylactic or therapeutic efficacy against S. aureus infections.

Burden and Risk Factors for Coinfections in Patients with a Viral Respiratory Tract Infection

Which patients should be monitored for coinfections or should receive empirical antibiotic treatment, in patients with an acute viral respiratory infection, is largely unknown. We evaluated the prevalence, characteristics, outcomes of coinfected patients, and risk factors associated with a coinfection among patients with an acute viral infection. A retrospective, single-center study recruited consecutive patients from October 2022 to March 2023 presenting to the emergency department with signs of a respiratory tract infection. Patients were screened for respiratory viruses and bacterial/fungal secondary infections according to local standard procedures. Outcomes included severe disease, in-hospital complications, all-cause in-hospital and ICU-related mortality, time to death, time to discharge, and time to coinfection. The analysis included 652 patients. A viral infection and a secondary bacterial/fungal infection were detected in 39.1% and 40% of cases. Compared with the rest of the cohort, coinfected patients had more frequently severe disease (88.3%, p < 0.001; 51% in patients with SARS-CoV-2) and higher in-hospital mortality (16.5%, p = 0.010). Nephropathy (OR 3.649, p = 0.007), absence of COVID-19 vaccination (OR 0.160, p < 0.001), SARS-CoV-2 infection (OR 2.390, p = 0.017), and lower blood pressure at admission (OR 0.980, p = 0.007) were independent risk factors for coinfection. Multidrug-resistant pathogens were detected in 30.8% of all coinfections. Patients with a viral infection are at high risk of bacterial coinfections, which carry a significant morbidity and mortality burden.

Design and synthesis of novel 2-(2-(4-bromophenyl)quinolin-4-yl)-1,3,4-oxadiazole derivatives as anticancer and antimicrobial candidates: in vitro and in silico studies

Cancer is the second leading cause of death globally, surpassed only by heart disease. Moreover, bacterial infections remain a significant global health burden, contributing substantially to morbidity and mortality, especially among hospitalized patients. EGFR has emerged as a prime therapeutic target due to its pivotal role in driving uncontrolled cell growth and survival across numerous cancer types. In addition, DNA gyrase represents a promising target for the development of novel antimicrobial agents. Therefore, we aimed to design and synthesize new multi-target quinoline hybrids (7-17e) capable of acting as anti-proliferative and antimicrobial agents by inhibiting EGFR and microbial DNA gyrase, respectively. The inhibitory potential of the synthesized compounds was determined using in vitro and in silico approaches. The antiproliferative activity of the synthesized quinoline-oxadiazole derivatives 7-17e was assessed against two cancer cell lines, namely, hepatocellular carcinoma (HepG2) and breast adenocarcinoma (MCF-7). The assessed compounds 7-17e showed considerable cytotoxic activity activities against HepG2 and MCF-7 with IC50 values of 0.137-0.332 and 0.164-0.583 μg mL-1, respectively, in comparison to erlotinib as the positive control, which showed an IC50 value of 0.308 and 0.512 μg mL-1, respectively. Moreover, an EGFR tyrosine kinase inhibition assay was conducted on the most prominent candidates. The results showed good IC50 values of 0.14 and 0.18 μM for compounds 8c and 12d, respectively, compared to lapatinib (IC50 value of 0.12 μM). Furthermore, the minimum antimicrobial inhibitory concentration was evaluated for the most prominent candidates with S. aureus, E. coli, and C. albicans. Compounds 17b, 17d and 17e displayed the most potent inhibitory activity, exhibiting 4-, 16- and 8-fold more activity, respectively, than the reference neomycin. Hence, we can conclude that the afforded compounds can be used as lead dual anticancer and antimicrobial candidates for future optimization.

A multiantigenic antibacterial nanovaccine utilizing hybrid membrane vesicles for combating Pseudomonas aeruginosa infections

Bacterial infections, especially those caused by multidrug-resistant pathogens, pose a significant threat to public health. Vaccines are a crucial tool in fighting these infections; however, no clinically available vaccine exists for the most common bacterial infections, such as those caused by Pseudomonas aeruginosa. Herein, a multiantigenic antibacterial nanovaccine (AuNP@HMV@SPs) is reported to combat P. aeruginosa infections. This nanovaccine utilizes the hybrid membrane vesicles (HMVs) created by fusing macrophage membrane vesicles (MMVs) with bacterial outer membrane vesicles (OMVs). The HMVs mitigate the toxic effects of both OMVs and bacterial secreted toxins (SP) adsorbed on the surface of MMVs, while preserving their stimulating properties. Gold nanoparticles (AuNPs) are utilized as adjuvant to enhance immune response without comprising safety. The nanovaccine AuNP@HMV@SPs induces robust humoral and cellular immune responses, leading to destruction of bacterial cells and neutralization of their secreted toxins. In murine models of septicemia and pneumonia caused by P. aeruginosa, AuNP@HMV@SPs exhibits superior prophylactic efficacy compared to control groups including OMVs, or MMVs@SPs and HMV@SPs, achieving 100% survival in septicemia and > 99.9% reduction in lung bacterial load in pneumonia. This study highlights AuNP@HMV@SPs as a safe and effective antibacterial nanovaccine, targeting both bacteria and their secreted toxins, and offers a promising platform for developing multiantigenic antibacterial vaccines against multidrug-resistant pathogens.

On-site detection of methicillin-resistant Staphylococcus aureus (MRSA) utilizing G-quadruplex based isothermal exponential amplification reaction (GQ-EXPAR)

Methicillin-resistant Staphylococcus aureus (MRSA) has a high incidence in infectious hospitals and communities, highlighting the need for early on-site detection due to its resistance to methicillin antibiotics. The present study introduces a highly sensitive detection system for mecA, a crucial methicillin marker, utilizing an RCA-based isothermal exponential amplification reaction. The G-quadruplex-based isothermal exponential amplification reaction (GQ-EXPAR) method designs probes to establish G-quadruplex secondary structures incorporating thioflavin T for fluorescence. The system, unlike conventional genetic detection methods, works with portable isothermal PCR devices (isoQuark), facilitating on-site detection. A detection limit of 0.1 fmol was demonstrated using synthetic DNA, and effective detection was proven using thermal lysis. The study also validated the detection of targets swabbed from surfaces within bacterial 3D nanostructures using the GQ-EXPAR method. After applying complementary sequences to the padlock probe for the target, the GQ-EXPAR method can be used on various targets. The developed method could facilitate rapid and accurate diagnostics within MRSA strains.

Design of multi-epitope vaccine candidate based on OmpA, CarO and ZnuD proteins against multi-drug resistant Acinetobacter baumannii

Acinetobacter baumannii has been identified as a major cause of nosocomial infections. Acinetobacter infections are often difficult to treat with multidrug resistant phenotypes. One of the most effective ways to combat infectious diseases is through vaccination. In this study, an attempt was made to select the most protective and potent immunostimulatory epitopes based on the epitope-rich domains of the ZnuD, OmpA and CarO proteins of Acinetobacter baumannii to design a vaccine that can protect against this infection. After predicting the epitope of B- and T-cells, seven antigenic regions of three proteins CarO, ZnuD and OmpA, were selected. These regions were bound by a GGGS linker. The binding affinity and molecular interactions of the vaccine with the immune receptors TLR2 and TLR4 were studied using molecular docking analysis. This vaccine design was subjected to in silico immune simulations using C-ImmSim. The designed vaccine was highly antigenic, non-allergenic and stable. TLR2 and TLR4 were selected to analyze the ability of the modeled chimeric protein to interact with immune system receptors. The results showed strong interaction between the designed protein vaccine with TLR2 (-18.8 kcal mol-1) and TLR4 (-15.1 kcal mol-1). To verify the stability of the interactions and the structure of the designed protein, molecular dynamics (MD) simulations were performed for 200 ns. Various analyses using MD showed that the protein structure is stable alone and in interaction with TLR2 and TLR4. The ability of the vaccine candidate protein to stimulate the immune system to produce the necessary cytokines and antibodies against Acinetobacter baumannii was also demonstrated by the ability of the protein designed using the C-ImmSim web server to induce an immune response. Therefore, the designed protein vaccine may be a suitable candidate for in vivo as well as in vitro studies against Acinetobacter baumannii infections.

A Structured Narrative Literature Review of the Broader Value of Adult Immunisation Programmes

Vaccine-preventable diseases continue to generate a substantial burden on health, healthcare systems, and societies, which is projected to increase with population ageing. There is a need to better understand the full value of adult immunisation programmes corresponding to the broader value of vaccine frameworks that are recommended for evidence-based decision-making. This review aims to summarise and map evidence for the value of selected adult immunisation programmes (seasonal influenza, pneumococcal disease, RSV, and HZ) in ten diverse countries. We conducted a structured literature review of evidence published from 2017 to 2023. An existing framework was used to structure the assessment, developing matrices demonstrating the elements of value evidenced for each vaccine and country of focus. Our analysis showed substantial evidence base on the value of adult immunisation programmes, but the availability of evidence varied by value element and by vaccine. The impact on the quality of life of the vaccinated individual was the most evidenced value element. Mortality benefits for vaccinated individuals and cost-offsets to healthcare systems were also well-evidenced. The availability of evidence for 'broader' societal value elements (such as transmission value, carer productivity and impact on social equity, and antimicrobial resistance prevention) varied. No evidence was identified relating to the broader value elements of macroeconomic effects, value to other interventions, or effects on the quality of life of caregivers. Robust evidence exists to show that adult immunisation programmes generate substantial value for population health and health systems, yet some elements of broader value remain underrepresented in the academic literature. Without such evidence, the full value of immunisation programmes is underestimated, risking suboptimal policy decisions.

The Impact of Vaccination as a Strategy to Combat Bacterial Antimicrobial Resistance

Antimicrobial resistance (AMR) poses a significant threat to global health, impairing the efficacy of treatments against various infections. The World Health Organization highlights the impact of AMR on healthcare outcomes, including increased morbidity, mortality, and costs. Vaccination is a pivotal strategy to counter AMR, promoting immune defenses against infections and subsequently reducing the need for antimicrobials. This article assesses the role of vaccination in managing AMR, particularly within the scope of antimicrobial stewardship programs (ASPs), by reviewing the effectiveness of existing vaccination strategies and their integration into the community. A comprehensive literature review was concluded using databases such as Google Scholar, Scielo, and PubMed, analyzing studies from 2005 to 2024. A total of 13 studies were included after screening 132 articles for relevance and eligibility. The studies highlight the substantial role of vaccines in reducing the reliance on antibiotics, especially for vulnerable populations, such as the elderly, children, and those with chronic conditions. For instance, the introduction of conjugate pneumococcal vaccines significantly decreased rates of drug-resistant Streptococcus pneumoniae infections. The review also discusses the indirect benefits of widespread vaccination, including herd immunity and decreased transmission of resistant strains. Vaccination is a critical element in the fight against AMR. Well-coordinated ASPs, by facilitating comprehensive vaccination programs, can significantly mitigate the rise of resistant infections, optimize antimicrobial usage, and improve patient outcomes in healthcare settings. The strategies outlined reflect global health objectives and emphasize the need for sustained efforts to enhance vaccine coverage and acceptance.

Antimicrobial resistance in China across human, animal, and environment sectors - a review of policy documents using a governance framework

Antimicrobial resistance (AMR) poses a multifaceted threat to the human, animal, and environment sectors. In response, China has formulated a series of policies since the 2000s. Thus far, there has been no comprehensive assessment of these policy documents. This study aims to review the content of AMR policy documents at the national level using a governance framework covering three areas: Policy Design; Implementation Tools; and Monitoring and Evaluation. We identified 44 AMR documents from 2003 to 2022 sourced from government agency websites. Our findings have revealed noticeable discrepancies across the three governance areas. The Policy Design and Monitoring and Evaluation areas should be strengthened, particularly in the domains of 'Coordination', 'Accountability', 'Sustainability', and 'Effectiveness'. From a 'One Health' perspective, the environment sector has received less attention compared to the human and animal sectors. Effectively addressing these challenges requires a stronger commitment and widespread support from diverse stakeholders.

Resistome in a changing environment: Hotspots and vectors of spreading with a focus on the Russian-Ukrainian War

This work aims to shed light on the key factors contributing to the development of environmental resistance and the urgent need to address the growing problem of antibiotic resistance (AR) under the Russian-Ukrainian conflict. The article provides an overview of the main mechanisms involved in AR development and dissemination globally and the challenges posed by the ongoing war in Ukraine. The work outlines various international initiatives to reduce AR, including the concept of "One Health" and the strategies established, which are the key to reducing the effects on public health. Addressing AR globally and in conflict areas requires a comprehensive approach. This involves implementing monitoring of the microorganism's resistance levels to antibiotics, controlling the use of antimicrobial drugs, increasing public awareness of the AR, introducing educational programs to prevent the improper use of antibiotics, and adopting environmentally safe methods for the disposal of waste from medical, food, and other industries that produce or use antibiotics. Such initiatives are essential for promoting the responsible use of antibiotics, preventing the spread of AR infections, and preserving the effectiveness of existing antimicrobial drugs.

β-Lactamase and Macrolide Resistance Gene Carriage in Escherichia coli Isolates Among Children Discharged From Inpatient Care in Western Kenya: A Cross-sectional Study

Background

Antimicrobial resistance (AMR) is a global threat to infectious disease control, particularly among recently hospitalized children. We sought to determine the prevalence and mitigating factors of resistance in enteric Escherichia coli among children discharged from health facilities in western Kenya.

Methods

Between June 2016 and November 2019, children aged 1 to 59 months were enrolled at the point of discharge from the hospital. E coli was isolated by microbiological culture from rectal swabs at baseline. β-Lactamases and macrolide resistance-conferring genes were detected by polymerase chain reaction. A modified Poisson regression model was used to assess the predictors mph(A) and CTX-M-type extended-spectrum β-lactamase (ESBL).

Results

Of the 238 children whose E coli isolates were tested, 91 (38.2%) and 109 (45.8%) had detectable CTX-M-type ESBL and mph(A) genes, respectively. Antibiotic treatment during hospitalization (adjusted prevalence ratio [aPR], 2.47; 95% CI, 1.12-5.43; P = .025), length of hospitalization (aPR, 1.42; 95% CI, 1.00-2.01; P = .052), and the practice of open defecation (aPR, 2.47; 95% CI, 1.40-4.36; P = .002) were independent predictors for CTX-M-type ESBL and mph(A) genes. Pneumococcal vaccination was associated with a 43% lower likelihood of CTX-M-type ESBL (aPR, 0.57; 95% CI, .38-.85; P = .005), while measles vaccination was associated with a 32% lower likelihood of mph(A) genes (aPR, 0.68; 95% CI, .49-.93; P = .017) in E coli isolates.

Conclusions

Among children discharged from the hospital, history of vaccination, shorter hospital stay, lack of in-hospital antibiotic exposure, and improved sanitation were associated with a lower likelihood of AMR genes. To mitigate the continued spread of AMR, AMR control programs should consider strategies beyond antimicrobial stewardship, including improvements in sanitation, increased vaccine coverage, and the development of novel vaccines.

Recent advances in micro/nanomotors for antibacterial applications

Currently, the rapid spread of multidrug-resistant bacteria derived from the indiscriminate use of traditional antibiotics poses a significant threat to public health worldwide. Moreover, established bacterial biofilms are extremely difficult to eradicate because of their high tolerance to traditional antimicrobial agents and extraordinary resistance to phagocytosis. Hence, it is of universal significance to develop novel robust and efficient antibacterial strategies to combat bacterial infections. Micro/nanomotors exhibit many intriguing properties, including enhanced mass transfer and micro-mixing resulting from their locomotion, intrinsic antimicrobial capabilities, active cargo delivery, and targeted treatment with precise micromanipulation, which facilitate the targeted delivery of antimicrobials to infected sites and their deep permeation into sites of bacterial biofilms for fast inactivation. Thus, the ideal antimicrobial activity of antibacterial micro/nanorobots makes them desirable alternatives to traditional antimicrobial treatments and has aroused extensive interest in recent years. In this review, recent advancements in antibacterial micro/nanomotors are briefly summarized, focusing on their synthetic methods, propulsion mechanism, and versatile antibacterial applications. Finally, some personal insights into the current challenges and possible future directions to translate proof-of-concept research to clinic application are proposed.

From Protection to Prevention: Redefining Vaccines in the Context of Antimicrobial Resistance

Antimicrobial resistance (AMR) poses a significant threat to global health, compromising the effectiveness of treatments and increasing medical risks. In this crisis, the importance of vaccines in reducing AMR is being increasingly acknowledged, although not thoroughly explored. This literature review asserts that vaccines can significantly lessen the occurrence of infections, thereby reducing the need for antibiotics and limiting the emergence of resistance. Vaccines play a crucial role in antimicrobial stewardship programs by preventing diseases that would otherwise necessitate the use of antibiotics. Expanding vaccine coverage supports responsible usage of antimicrobials and aligns with global health priorities to maintain effective medical interventions. This review emphasizes the need for equitable funding and policy support for vaccine initiatives comparable to new antibiotics and diagnostic techniques. Moreover, it calls for more detailed investigations into vaccines' economic and health benefits in managing AMR, highlighting their potential as cost-effective solutions to this urgent health challenge. Through a careful analysis of existing literature, this review highlights the fundamental role of vaccines in transforming the landscape of AMR, shifting the focus from a protective approach to a preventive health strategy.

Programmed Nanocloak of Commensal Bacteria-Derived Nanovesicles Amplify Strong Immunoreactivity against Tumor Growth and Metastatic Progression

Recent discoveries in commensal microbiota demonstrate the great promise of intratumoral bacteria as attractive molecular targets of tumors in improving cancer treatment. However, direct leveraging of in vivo antibacterial strategies such as antibiotics to potentiate cancer therapy often leads to uncertain effectiveness, mainly due to poor selectivity and potential adverse effects. Here, building from the clinical discovery that patients with breast cancer featured rich commensal bacteria, we developed an activatable biointerface by encapsulating commensal bacteria-derived extracellular vesicles (BEV) with a responsive nanocloak to potentiate immunoreactivity against intratumoral bacteria and breast cancer. We show that the interfacially cloaked BEV (cBEV) not only overcame serious systemic side responses but also demonstrated heightened immunogenicity by intercellular responsive immunogenicity, facilitating dendritic cell maturation through activating the cGAS-STING pathway. As a preventive measure, vaccination with nanocloaked cBEVs achieved strong protection against bacterial infection, largely providing prophylactic efficiency against tumor challenges. When treated in conjunction with immune checkpoint inhibitor anti-PD-L1 antibodies, the combined approach elicited a potent tumor-specific immune response, synergistically inhibiting tumor progression and mitigating lung metastases.

Photo-Responsive Ascorbic Acid-Modified Ag2S-ZnS Heteronanostructure Dropping pH to Trigger Synergistic Antibacterial and Bohr Effects for Accelerating Infected Wound Healing

Nonantibiotic approaches must be developed to kill pathogenic bacteria and ensure that clinicians have a means to treat wounds that are infected by multidrug-resistant bacteria. This study prepared matchstick-like Ag2S-ZnS heteronanostructures (HNSs). Their hydrophobic surfactants were then replaced with hydrophilic poly(ethylene glycol) (PEG) and thioglycolic acid (TGA) through the ligand exchange method, and this was followed by ascorbic acid (AA) conjugation with TGA through esterification, yielding well-dispersed PEGylated Ag2S-ZnS@TGA-AA HNSs. The ZnS component of the HNSs has innate semiconductivity, enabling the generation of electron-hole pairs upon irradiation with a light of wavelength 320 nm. These separate charges can react with oxygen and water around the HNSs to produce reactive oxygen species. Moreover, some holes can oxidize the surface-grafted AA to produce protons, decreasing the local pH and resulting in the corrosion of Ag2S, which releases silver ions. In evaluation tests, the PEGylated Ag2S-ZnS@TGA-AA had synergistic antibacterial ability and inhibited Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA). Additionally, MRSA-infected wounds treated with a single dose of PEGylated Ag2S-ZnS@TGA-AA HNSs under light exposure healed significantly more quickly than those not treated, a result attributable to the HNSs' excellent antibacterial and Bohr effects.

Fiscal analysis of the pediatric immunization program in Belgium applying a lifetime government perspective framework

OBJECTIVES

A public economic framework was used to explore lifetime government costs and benefits in relation to the Pediatric Immunization Program (PIP) in Belgium based on cases and deaths averted.

METHODS

To estimate changes in net government revenue, we developed a decision-analytic model that quantifies lifetime tax revenues and transfers based on changes in morbidity and mortality arising from Belgium's Pediatric Immunization Program (PIP). The model considered differences in incidence rates with vaccines included in Belgium's PIP: compared with the pre-vaccine era. Changes in deaths and comorbid conditions attributed to PIP on the Belgium 2020 birth cohort were used to estimate gross lifetime earnings changes, tax revenue gains attributed to averted morbidity and mortality avoidance, disability transfer cost savings, and averted special education costs associated with each vaccine.

RESULTS

Vaccinating a single birth cohort according to the PIP gives rise to fiscal gains of €56 million in averted tax revenue loss, €8 million disability savings, and €6 million special education cost-savings. Based on the costs of implementing the PIP, we estimate the fiscal benefit-cost ratio (fBCR) of €2.2 investment return for the government from every €1 invested excluding longevity costs.

CONCLUSIONS

Reducing vaccine-preventable conditions generates tax revenue for the government, providing fiscal justification for sustained immunization investments.

A systematic review on the excess health risk of antibiotic-resistant bloodstream infections for six key pathogens in Europe

BACKGROUND

Antimicrobial resistance is a global threat, which requires novel intervention strategies, for which priority pathogens and settings need to be determined.

OBJECTIVES

We evaluated pathogen-specific excess health burden of drug-resistant bloodstream infections (BSIs) in Europe.

METHODS

A systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, and grey literature for the period January 1990 to May 2022.

STUDY ELIGIBILITY CRITERIA

Studies that reported burden data for six key drug-resistant pathogens: carbapenem-resistant (CR) Pseudomonas aeruginosa and Acinetobacter baumannii, third-generation cephalosporin or CR Escherichia coli and Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium. Excess health outcomes compared with drug-susceptible BSIs or uninfected patients. For MRSA and third-generation cephalosporin E. coli and K. pneumoniae BSIs, five or more European studies were identified. For all others, the search was extended to high-income countries.

PARTICIPANTS

Paediatric and adult patients diagnosed with drug-resistant BSI.

INTERVENTIONS

Not applicable.

ASSESSMENT OF RISK OF BIAS

An adapted version of the Joanna-Briggs Institute assessment tool.

METHODS OF DATA SYNTHESIS

Random-effect models were used to pool pathogen-specific burden estimates.

RESULTS

We screened 7154 titles, 1078 full-texts and found 56 studies on BSIs. Most studies compared outcomes of drug-resistant to drug-susceptible BSIs (46/56, 82.1%), and reported mortality (55/56 studies, 98.6%). The pooled crude estimate for excess all-cause mortality of drug-resistant versus drug-susceptible BSIs ranged from OR 1.31 (95% CI 1.03-1.68) for CR P. aeruginosa to OR 3.44 (95% CI 1.62-7.32) for CR K. pneumoniae. Pooled crude estimates comparing mortality to uninfected patients were available for vancomycin-resistant Enterococcus and MRSA BSIs (OR of 11.19 [95% CI 6.92-18.09] and OR 6.18 [95% CI 2.10-18.17], respectively).

CONCLUSIONS

Drug-resistant BSIs are associated with increased mortality, with the magnitude of the effect influenced by pathogen type and comparator. Future research should address crucial knowledge gaps in pathogen- and infection-specific burdens to guide development of novel interventions.

Monoclonal Antibodies as a Therapeutic Strategy against Multidrug-Resistant Bacterial Infections in a Post-COVID-19 Era

The development of severe multidrug-resistant bacterial infections has recently intensified because of the COVID-19 pandemic. According to the guidelines issued by the World Health Organization (WHO), routine antibiotic administration is not recommended for patients with supposed or confirmed mild SARS-CoV-2 infection or pneumonia, unless bacterial infection is clinically suspected. However, recent studies have pointed out that the proportion of non-essential antibiotic use in patients infected with SARS-CoV-2 remains high. Therefore, the silent pandemic of antibiotic resistance remains a pressing issue regardless of the present threats presented by the COVID-19 pandemic. To prevent or delay entry into the postulated post-antibiotic era, the long-term advocacy for the rational use of antibiotics, the optimization of infection control procedures, and the development of new antibacterial agents and vaccines should be underscored as vital practices of the antibacterial toolbox. Recently, the development of vaccines and monoclonal antibodies has gradually received attention following the advancement of biotechnology as well as enhanced drug discovery and development in cancer research. Although decent progress has been made in laboratory-based research and promising results have been obtained following clinical trials of some of these products, challenges still exist in their widespread clinical applications. This article describes the current advantages of antibacterial monoclonal antibodies, the development of associated clinical trials, and some perceived future perspectives and challenges. Further, we anticipate the development of more therapeutic agents to combat drug-resistant bacterial infections as well as to increase the resilience of current or novel agents/strategies.

Detection of immune effects of the Mannheimia haemolytica gamma irradiated vaccine in sheep

Exposure to gamma rays from cobalt 60 (Co60) can induce a complete inactivation of Mannheimia haemolytica. The inactivated bacterial pathogen is a potential vaccine candidate for immunization of ruminants such as sheep. The subcutaneous administration of irradiated vaccine in a two-dose regimen (4.0 × 109 colony forming unit (CFU) per dose) results in no mortality in any of the vaccinated sheep during immunization and after subsequent challenge of the live bacteria of the same strain of M. haemolytica. A significant rise in serum IgG titer, detected through ELISA, is observed after the passage of two weeks from the inoculation of the first dose whereas, the peak of the mean serum antibody titer occurred after two weeks of booster dose. The vaccination does not bring significant change to the IFN-γ levels in serum. The bacterial challenge of the vaccinated sheep does not induce a further seroconversion relative to serum antibody titer. In conclusion, the vaccinated sheep are protected by the elevated IgG titer and increased levels of IL-4 (Th-2 response) compared to the non-vaccinated sheep. Radiation technology can provide the opportunity for mass production of immunologically safe vaccines against animal and zoonotic diseases. Ethics Approval by the National Research Center Ethics Committee (Trial Registration Number (TRN) no 13,602,023, 13/5/2023) was obtained.

Transient comparison of techniques to counter multi-drug resistant bacteria: prime modules in curation of bacterial infections

Multidrug-resistant organisms are bacteria that are no longer controlled or killed by specific drugs. One of two methods causes bacteria multidrug resistance (MDR); first, these bacteria may disguise multiple cell genes coding for drug resistance to a single treatment on resistance (R) plasmids. Second, increased expression of genes coding for multidrug efflux pumps, which extrude many drugs, can cause MDR. Antibiotic resistance is a big issue since some bacteria may withstand almost all antibiotics. These bacteria can cause serious sickness, making them a public health threat. Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), Multidrug resistant Mycobacterium tuberculosis (TB), and CRE are gut bacteria that resist antibiotics. Antimicrobial resistance is rising worldwide, increasing clinical and community morbidity and mortality. Superbugs have made antibiotic resistance in some environmental niches even harder to control. This study introduces new medicinal plants, gene-editing methods, nanomaterials, and bacterial vaccines that will fight MDR bacteria in the future.

A colorimetric, photothermal, and fluorescent triple-mode CRISPR/cas biosensor for drug-resistance bacteria detection

A multimodal analytical strategy utilizing different modalities to cross-validate each other, can effectively minimize false positives or negatives and ensure the accuracy of detection results. Herein, we establish a colorimetric, photothermal, and fluorescent triple modal CRISPR/Cas12a detection platform (CPF-CRISPR). An MNPs-ssDNA-HRP signal probe is designed to act as a substrate to trigger three signal outputs. In the presence of the DNA target, MNPs-ssDNA-HRP is cleaved by the activated CRISPR/Cas12a, resulting in the release of HRP and generating short DNA strands with 3-terminal hydroxyl on magnetic beads. The released HRP subsequently catalyzed TMB-H2O2 reaction and oxidized TMB is used for colorimetric and photothermal signal detection. Under the catalysis of terminal deoxynucleotidyl transferase (TdT), the remaining short DNA strands are used as primers to form poly-T and function as scaffolds to form copper nanoclusters for fluorescent signal output. To verify the practical application of CPF-CRISPR, we employed MRSA as a model. The results demonstrate the platform's high accuracy and sensitivity, with a limit of detection of 101 CFU/mL when combined with recombinase polymerase amplification. Therefore, by harnessing the programmability of CRISPR/Cas12a, the biosensor has the potential to detect various drug-resistant bacteria, demonstrating significant practical applicability.

Global trends in antimicrobial resistance on organic and conventional farms

The important hypothesis that organic livestock management reduces the prevalence of antimicrobial resistance is either fiercely supported or bitterly contested. Yet, empirical evidence supporting this view remains fragmentary, in part because relationships between antimicrobial use and drug resistance vary dramatically across contexts, hosts, pathogens, and country-specific regulations. Here, we synthesize global policies and definitions of 'organic' and ask if organic farming results in notable reductions in the prevalence of antimicrobial resistance when directly examined alongside conventional analogs. We synthesized the results of 72 studies, spanning 22 countries and five pathogens. Our results highlight substantial variations in country-specific policies on drug use and definitions of 'organic' that hinder broad-scale and generalizable patterns. Overall, conventional farms had slightly higher levels of antimicrobial resistance (28%) relative to organic counterparts (18%), although we found significant context-dependent variation in this pattern. Notably, environmental samples from organic and conventional farms often exhibited high levels of resistance to medically important drugs, underscoring the need for more stringent and consistent policies to control antimicrobial contaminants in the soil (particularly on organic farms, where the application of conventional manure could faciliate the spread antimicrobial resistance). Taken together, these results emphasize the challenges inherent in understanding links between drug use and drug resistance, the critical need for global standards governing organic policies, and greater investment in viable alternatives for managing disease in livestock.

Longitudinal monitoring reveals the emergence and spread of blaGES-5-harboring carbapenem-resistant Klebsiella quasipneumoniae in a Hong Kong hospital wastewater discharge line

Testing hospital wastewater (HWW) is potentially an effective, long-term approach for monitoring trends in antimicrobial resistance (AMR) patterns in health care institutions. Over a year, we collected wastewater samples from the clinical and non-clinical sites of a tertiary hospital and from a downstream wastewater treatment plant (WWTP). We focused on the extent of carbapenem resistance among Enterobacteriaceae isolates given their clinical importance. Escherichia coli and Klebsiella spp. were the most frequently isolated Enterobacteriaceae species at all sampling sites. Additionally, a small number of isolates belonging to ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), except K. pneumoniae, were detected. Of the 232 Klebsiella spp. isolates, 100 (43.1 %) were multi-drug resistant (MDR), with 46 being carbapenem-resistant. Most of these carbapenem-resistant isolates were K. quasipneumoniae (CRKQ) (n = 44). All CRKQ isolates were isolated from the wastewater of a clinical site that includes intensive care units, which also yielded significantly more multi-drug resistant isolates compared to all other sampling sites. Among the CRKQ isolates, blaGES-5 genes (n = 42) were the primary genetic determinant of carbapenem resistance. Notably, three different CRKQ isolates, collected within the same month in HWW and the influent and effluent flow of the WWTP, shared >99 % sequence similarity between their blaGES-5 genes and between their flanking regions and upstream integron-integrase region. The influent isolate was phylogenetically close to K. quasipnuemoniae isolates from wastewater collected in Japan. Its blaGES-5 gene and surrounding sequences were > 99 % identical to blaGES-24 genes found in the Japanese isolates. Our results suggest that testing samples from sites located closer to hospitals could support antibiotic stewardship programs compared to samples collected further downstream. Moreover, testing samples collected regularly from WWTPs may reflect the local and global spread of pathogens and their resistances.

Potential Causes of Spread of Antimicrobial Resistance and Preventive Measures in One Health Perspective-A Review

Antimicrobial resistance, referring to microorganisms' capability to subsist and proliferate even when there are antimicrobials is a foremost threat to public health globally. The appearance of antimicrobial resistance can be ascribed to anthropological, animal, and environmental factors. Human-related causes include antimicrobial overuse and misuse in medicine, antibiotic-containing cosmetics and biocides utilization, and inadequate sanitation and hygiene in public settings. Prophylactic and therapeutic antimicrobial misuse and overuse, using antimicrobials as feed additives, microbes resistant to antibiotics and resistance genes in animal excreta, and antimicrobial residue found in animal-origin food and excreta are animals related contributive factors for the antibiotic resistance emergence and spread. Environmental factors including naturally existing resistance genes, improper disposal of unused antimicrobials, contamination from waste in public settings, animal farms, and pharmaceutical industries, and the use of agricultural and sanitation chemicals facilitatet its emergence and spread. Wildlife has a plausible role in the antimicrobial resistance spread. Adopting a one-health approach involving using antimicrobials properly in animals and humans, improving sanitation in public spaces and farms, and implementing coordinated governmental regulations is crucial for combating antimicrobial resistance. Collaborative and cooperative involvement of stakeholders in public, veterinary and ecological health sectors is foremost to circumvent the problem effectively.

Co-regulation of biofilm formation and antimicrobial resistance in Acinetobacter baumannii: from mechanisms to therapeutic strategies

In recent years, multidrug-resistant Acinetobacter baumannii has emerged globally as a major threat to the healthcare system. It is now listed by the World Health Organization as a priority one for the need of new therapeutic agents. A. baumannii has the capacity to develop robust biofilms on biotic and abiotic surfaces. Biofilm development allows these bacteria to resist various environmental stressors, including antibiotics and lack of nutrients or water, which in turn allows the persistence of A. baumannii in the hospital environment and further outbreaks. Investigation into therapeutic alternatives that will act on both biofilm formation and antimicrobial resistance (AMR) is sorely needed. The aim of the present review is to critically discuss the various mechanisms by which AMR and biofilm formation may be co-regulated in A. baumannii in an attempt to shed light on paths towards novel therapeutic opportunities. After discussing the clinical importance of A. baumannii, this critical review highlights biofilm-formation genes that may be associated with the co-regulation of AMR. Particularly worthy of consideration are genes regulating the quorum sensing system AbaI/AbaR, AbOmpA (OmpA protein), Bap (biofilm-associated protein), the two-component regulatory system BfmRS, the PER-1 β-lactamase, EpsA, and PTK. Finally, this review discusses ongoing experimental therapeutic strategies to fight A. baumannii infections, namely vaccine development, quorum sensing interference, nanoparticles, metal ions, natural products, antimicrobial peptides, and phage therapy. A better understanding of the mechanisms that co-regulate biofilm formation and AMR will help identify new therapeutic targets, as combined approaches may confer synergistic benefits for effective and safer treatments.

Importance of adjuvant selection in tuberculosis vaccine development: Exploring basic mechanisms and clinical implications

The global emergency of unexpected pathogens, exemplified by SARS-CoV-2, has emphasized the importance of vaccines in thwarting infection and curtailing the progression of severe disease. The scourge of tuberculosis (TB), emanating from the Mycobacterium tuberculosis (Mtb) complex, has inflicted a more profound toll in terms of mortality and morbidity than any other infectious agents prior to the SARS-CoV-2 pandemic. Despite the existence of Bacillus Calmette-Guérin (BCG), the only licensed vaccine developed a century ago, its efficacy against TB remains unsatisfactory, particularly in preventing pulmonary Mtb infections in adolescents and adults. However, collaborations between academic and industrial entities have led to a renewed impetus in the development of TB vaccines, with numerous candidates, particularly subunit vaccines with specialized adjuvants, exhibiting promising outcomes in recent clinical studies. Adjuvants are crucial in modulating optimal immunological responses, by endowing immune cells with sufficient antigen and immune signals. As exemplified by the COVID-19 vaccine landscape, the interplay between vaccine efficacy and adverse effects is of paramount importance, particularly for the elderly and individuals with underlying ailments such as diabetes and concurrent infections. In this regard, adjuvants hold the key to optimizing vaccine efficacy and safety. This review accentuates the pivotal roles of adjuvants and their underlying mechanisms in the development of TB vaccines. Furthermore, we expound on the prospects for the development of more efficacious adjuvants and their synergistic combinations for individuals in diverse states, such as aging, HIV co-infection, and diabetes, by examining the immunological alterations that arise with aging and comparing them with those observed in younger cohorts.

Klebsiella pneumoniae: adaptive immune landscapes and vaccine horizons

Klebsiella pneumoniae is among the most common antibiotic-resistant pathogens causing nosocomial infections. Additionally, it is a leading cause of neonatal sepsis and childhood mortality across the globe. Despite its clinical importance, we are only beginning to understand how the mammalian adaptive immune system responds to this pathogen. Further, many studies investigating potential K. pneumoniae vaccine candidates or alternative therapies have been launched in recent years. Here, we review the current state of knowledge on the adaptive immune response to K. pneumoniae infections and progress towards developing vaccines and other therapies to combat these infections.

What are the missing pieces needed to stop antibiotic resistance?

As recognized by several international agencies, antibiotic resistance is nowadays one of the most relevant problems for human health. While this problem was alleviated with the introduction of new antibiotics into the market in the golden age of antimicrobial discovery, nowadays few antibiotics are in the pipeline. Under these circumstances, a deep understanding on the mechanisms of emergence, evolution and transmission of antibiotic resistance, as well as on the consequences for the bacterial physiology of acquiring resistance is needed to implement novel strategies, beyond the development of new antibiotics or the restriction in the use of current ones, to more efficiently treat infections. There are still several aspects in the field of antibiotic resistance that are not fully understood. In the current article, we make a non-exhaustive critical review of some of them that we consider of special relevance, in the aim of presenting a snapshot of the studies that still need to be done to tackle antibiotic resistance.

Hit 'em Where It Hurts: Gram-Negative Bacterial Lipopolysaccharide as a Vaccine Target

Infections with antimicrobial-resistant (AMR) bacteria pose an increasing threat to the ability to perform surgical procedures, organ transplantation, and treat cancer among many other medical conditions. There are few new antimicrobials in the development pipeline. Vaccines against AMR Gram-negative bacteria may reduce the use of antimicrobials and prevent bacterial transmission. This review traces the origins of lipopolysaccharide (LPS)-based vaccines against Gram-negative bacteria, the role of O polysaccharides and LPS core regions as potential vaccine targets, the development of new vaccine technologies, and their application to vaccines in current development.

The Role of Adult Vaccines as Part of Antimicrobial Stewardship: A Scoping Review

BACKGROUND

Antimicrobial resistance (AMR) is a significant global health concern, causing an estimated 700,000 deaths annually. Although immunisation has been shown to significantly reduce AMR, the role of vaccines as part of antimicrobial stewardship (AMS) practices is often overlooked.

OBJECTIVE

To identify and examine the available literature on the role of vaccines as part of AMS practices.

METHOD

A scoping review was conducted in the following databases: MEDLINE, Embase, Scopus, CINAHL, CCRCT, IPA, and WoS, along with grey literature sources. The review was conducted using the JBI Methodology for Scoping Reviews and reported in line with the PRISMA-SCr checklist.

RESULTS

Among the 1711 records identified, 34 met the inclusion criteria; 8 discussed only the concept, while 26 discussed both the concept and the vaccine implementation method in AMS practices. There were eight recommended and/or utilised types of AMS activities identified involving vaccines, under four key themes of vaccine-related AMS strategies: Education, Screening, Vaccination, and Monitoring. Influenza and pneumococcal vaccines had the most evidence for inclusion.

CONCLUSION

Overall, the evidence supports the role of vaccines as part of AMS practices and the value of their inclusion in creating improved and comprehensive AMS strategies to further combat the development of AMR.

An Overview of Preventive Strategies and the Role of Various Organizations in Combating Antimicrobial Resistance

The rise of antimicrobial resistance (AMR) is a major global public health threat due to excessive and inappropriate use of antibiotics and is responsible for prolonged illness, longer hospital stays, and economic burden to society. This article aims to review the factors, role of antimicrobial stewardship, preventive strategies, and role of various organizations in combating AMR. Three major factors of AMR are inappropriate and excessive utilization of antibiotics, nonadherence to infection control measures, and the emergence of pathogens that are resistant to multiple drugs. Antimicrobial stewardship initiatives play a vital role in promoting judicious and targeted utilization of antimicrobials, thereby safeguarding their efficacy and mitigating the emergence of resistance. Implementing such programs optimizes patient outcomes by ensuring that individuals receive the most suitable therapeutic interventions. International organizations have a vital role to play in addressing AMR by promoting the responsible use of antimicrobials, developing new drugs, and improving surveillance systems. As AMR's impact grows, it is critical to take a collaborative and interdisciplinary approach to mitigate its consequences effectively.

[Antibiotic stewardship]

The spread of antimicrobial resistance (AMR) is one of the greatest threats to global health and causes very many deaths. Also in the context of sepsis-the severest complication of certain infectious diseases-does AMR play a role. Wise use of anti-infectives and application of antibiotic stewardship (AMS) principles can reduce the spread of AMR and improve the quality of management of patients with infectious diseases. Correct use of anti-infective agents includes the correct diagnostic approach and documentation of the (suspected) diagnosis, guideline-conform diagnostic workup and treatment selection, re-evaluation and tailoring during the course of treatment, a focus on treatment de-escalation depending on clinical response and microbiology results, dose optimization, and, if possible, conversion to oral therapy, and early termination of treatment if the suspected diagnosis is not confirmed. Particularly adherence to the guideline-conform treatment duration can reduce unnecessary use of anti-infectives. Prevention of infections via adherence to vaccination recommendations also contributes to a reduction in the use of anti-infectives. Interdisciplinary collaboration with infectious diseases and AMS specialists, as recommended for sepsis, also improves treatment quality and patient outcomes. Particularly for complex infections such as endocarditis cases should be discussed in multidisciplinary teams including specialists in infectious diseases. In this manner, decisive steps against the spread of AMR and towards maintenance of the efficacy of available anti-infective drugs can be taken.

Holistic Strategies to Control Salmonella Infantis: An Emerging Challenge in the European Broiler Sector

Salmonella spp. has been globally recognized as one of the leading causes of acute human bacterial gastroenteritis resulting from the consumption of animal-derived products. Salmonella Enteritidis, S. Typhimurium, and its monophasic variant are the main serovars responsible for human disease. However, a serovar known as S. Infantis has emerged as the fourth most prevalent serovar associated with human disease. A total of 95% of isolated S. Infantis serovars originate from broilers and their derived products. This serovar is strongly associated with an elevated antimicrobial (AMR) and multidrug resistance, a resistance to disinfectants, an increased tolerance to environmental mercury, a heightened virulence, and an enhanced ability to form biofilms and attach to host cells. Furthermore, this serovar harbors genes that confer resistance to colistin, a last-resort antibiotic in human medicine, and it has the potential to acquire additional transferable AMR against other critically important antimicrobials, posing a new and significant challenge to global public health. This review provides an overview of the current status of the S. Infantis serovar in the poultry sector, focusing on its key virulence factors, including its virulence genes, antimicrobial resistance, and biofilm formation. Additionally, novel holistic strategies for controlling S. Infantis along the entire food chain are presented in this review.

Liposome-based vaccines for minimally or noninvasive administration: an update on current advancements

INTRODUCTION

Vaccination requires innovation to provide effective protection. Traditional vaccines have several drawbacks, which can be overcome with advanced technologies and different administration routes. Over the past 10  years, a significant amount of research has focussed on the delivery of antigens into liposomes due to their dual role as antigen-carrying systems and vaccine adjuvants able to increase the immunogenicity of the carried antigen.

AREAS COVERED

This review encompasses the progress made over the last 10  years with liposome-based vaccines designed for minimally or noninvasive administration, filling the gaps in previous reviews and providing insights on composition, administration routes, results achieved, and Technology Readiness Level of the most recent formulations.

EXPERT OPINION

Liposome-based vaccines administered through minimally or noninvasive routes are expected to improve efficacy and complacency of vaccination programs. However, the translation from lab-scale production to large-scale production and collaborations with hospitals, research centers, and companies are needed to allow new products to enter the market and improve the vaccination programs in the future.

Scope and applicability of social-ecological resilience to antimicrobial resistance

Social-ecological systems conceptualise how social human systems and ecological natural systems are intertwined. In this Personal View, we define the scope and applicability of social-ecological resilience to antimicrobial resistance. Resilience to antimicrobial resistance corresponds to the capacity to maintain the societal benefits of antimicrobial use and One Health systems' performance in the face of the evolutionary behaviour of microorganisms in response to antimicrobial use. Social-ecological resilience provides an appropriate framework to make sense of the disruptive impacts resulting from the emergence and spread of antimicrobial resistance; capture the diversity of strategies needed to tackle antimicrobial resistance and to live with it; understand the conditions that underpin the success or failure of interventions; and appreciate the need for adaptive and coevolutionary governance. Overall, resilience thinking is essential to improve understanding of how human societies dynamically can cope with, adapt, and transform to the growing global challenge of antimicrobial resistance.

CRISPR-Based Gene Editing in Acinetobacter baumannii to Combat Antimicrobial Resistance

Antimicrobial resistance (AMR) poses a significant threat to the health, social, environment, and economic sectors on a global scale and requires serious attention to addressing this issue. Acinetobacter baumannii was given top priority among infectious bacteria because of its extensive resistance to nearly all antibiotic classes and treatment options. Carbapenem-resistant A. baumannii is classified as one of the critical-priority pathogens on the World Health Organization (WHO) priority list of antibiotic-resistant bacteria for effective drug development. Although available genetic manipulation approaches are successful in A. baumannii laboratory strains, they are limited when employed on newly acquired clinical strains since such strains have higher levels of AMR than those used to select them for genetic manipulation. Recently, the CRISPR-Cas (Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein) system has emerged as one of the most effective, efficient, and precise methods of genome editing and offers target-specific gene editing of AMR genes in a specific bacterial strain. CRISPR-based genome editing has been successfully applied in various bacterial strains to combat AMR; however, this strategy has not yet been extensively explored in A. baumannii. This review provides detailed insight into the progress, current scenario, and future potential of CRISPR-Cas usage for AMR-related gene manipulation in A. baumannii.

TonB-Dependent Receptor Protein Displayed on Spores of Bacillus subtilis Stimulates Protective Immune Responses against Acinetobacter baumannii

The emergence of antibiotic-resistant Acinetobacter baumannii strains with limited treatment options has become a significant global health concern. Efforts to develop vaccines against the bacteria have centred on several potential protein targets, including the TonB-dependent receptors (TBDRs). In the present study, TBDRs from A. baumannii were displayed on the surface of Bacillus subtilis spores. The immunogenicity of the recombinant spores was evaluated in orally vaccinated mice. None of the immunized mice demonstrated signs of illness and were observed to be healthy throughout the study. Sera and the intestinal secretions from the recombinant spores-treated mice demonstrated mucosal and humoral antibody responses to the vaccine antigen. In addition, bactericidal activities of the sera against A. baumannii clinical isolates were demonstrated. These observations suggest that the B. subtilis spore-displayed TBDRs should be further explored as much-needed potential oral vaccine candidates against A. baumannii.

Investing in health to improve the sustainability of cattle production in the United Kingdom: A narrative review

Livestock health is a key concern for all food system stakeholders and has considerable impacts upon sustainable food production. Improving productivity means that a set quantity of milk or meat may be produced at a lower economic cost, using fewer resources and with reduced greenhouse gas emissions (GHGe); however, diseases that reduce yield, growth or fertility have the opposite effect. The purpose of this narrative review was to assess the breadth of economic and environmental sustainability information relating to cattle health within the literature and to discuss related knowledge gaps within the literature. The mechanisms by which improved awareness and investment can lead to improved cattle health both on-farm and across the wider cattle industry are also appraised; concluding with the opportunities and challenges still outstanding in improving sustainability through livestock health. The economic and environmental impacts of cattle health have not been sufficiently quantified in the literature to draw valid conclusions regarding the sustainability impact of different diseases. Where available, economic data tended to be dated or extremely variable. Furthermore, environmental analyses did not use consistent methodologies and principally focused on GHGe, with little attention paid to other metrics. Although reducing disease severity or occurrence reduced GHGe, published impacts of disease varied from 1% to 40% with little apparent association between GHGe and industry-wide economic cost. An urgent need therefore exists to standardise methodologies and quantify disease impacts using a common baseline with up-to-date data inputs. Given the threat of antimicrobial resistance, improving cattle health through technology adoption and vaccine use would be expected to have positive impacts on social acceptability, especially if these improvements rendered milk and meat more affordable to the consumer. Therefore, it is important for cattle producers and allied industry to take a proactive approach to improving cattle health and welfare, with particular focus on diseases that have the greatest implications for sustainability.