The impact of human vaccines on bacterial antimicrobial resistance. A review.

At present, the dramatic rise in antimicrobial resistance (AMR) among important human bacterial pathogens is reaching a state of global crisis threatening a return to the pre-antibiotic era. AMR, already a significant burden on public health and economies, is anticipated to grow even more severe in the coming decades. Several licensed vaccines, targeting both bacterial (Haemophilus influenzae type b, Streptococcus pneumoniae, Salmonella enterica serovar Typhi) and viral (influenza virus, rotavirus) human pathogens, have already proven their anti-AMR benefits by reducing unwarranted antibiotic consumption and antibiotic-resistant bacterial strains and by promoting herd immunity. A number of new investigational vaccines, with a potential to reduce the spread of multidrug-resistant bacterial pathogens, are also in various stages of clinical development. Nevertheless, vaccines as a tool to combat AMR remain underappreciated and unfortunately underutilized. Global mobilization of public health and industry resources is key to maximizing the use of licensed vaccines, and the development of new prophylactic vaccines could have a profound impact on reducing AMR.

Design and Optimization of a Temperature-Stable Dry Powder BCG Vaccine.

PURPOSE: Loss of vaccine potency due to extreme temperature exposure during storage and transport remains a significant obstacle to the success of many vaccines, including the Bacille Calmette-Guérin (BCG) vaccine, the only vaccine available against Mycobacterium tuberculosis. BCG is a live, attenuated vaccine requiring refrigerated storage for viability. In this study, we formulated a temperature-stable BCG dry powder using the spray drying technique. METHODS: We employed a factorial design to optimize our formulation of stabilizing excipients that included L-leucine, bovine serum albumin, polyvinylpyrrolidone, mannitol, and trehalose. Powders were characterized for their particle size, yield, water retention and uptake, glass transition temperature, and aerosol performance. Three optimal powder carrier mixtures were selected from the factorial design for BCG incorporation based on their stability-promoting and powder flow characteristics. Vaccine powders were also assessed for BCG viability and in vivo immunogenicity after long-term storage. RESULTS: Live BCG was successfully spray-dried using the optimized carriers. Dry powder BCG showed no loss in viability (25°C, up to 60% relative humidity; RH) and ~2-log loss in viability (40°C, 75% RH) after one year of storage. The aerodynamic size of the powders was in the respirable range. Further, when healthy mice were immunized intradermally with reconstituted BCG powders (storage for 2 years), the vaccine retained its immunogenicity. CONCLUSION: We developed a spray-dried BCG vaccine that was viable and antigenic after long-term storage. To our knowledge, this is a first study to show room temperature stability of live BCG vaccine without any loss in viability for 12 months.

Active immunoprophyilaxis with uromune® decreases the recurrence of urinary tract infections at three and six months after treatment without relevant secondary effects.

BACKGROUND: To prospectively analyze the efficacy of uromune® in the prevention of uncomplicated recurrent urinary tract infections at 3 and 6 months, and according to gender and menopause. METHODS: From September 2011 to December 2017 uromune® was administered sublingually every 24 h along 3 months to 784 patients with history of three or more uncomplicated urinary tract infections in the 12 months prior to the first visit. The variables analyzed with statistical package system for science version 15.0 were age, gender, number of urinary tract infections with positive urine culture in the first consultation, and 3 and 6 months after the end of treatment. The results with positive urine culture were registered at 3 and 6 months after the end of the treatment according to gender and also in the menopausal group with respect to pre-menopausal women. RESULTS: Mean age was 73.5 years. 82.7% were women and 94.3% menopausal. The number of episodes of urinary tract infections in the 12 months prior to uromune® were 3 in 37.2%, 4 in 28.1%, 5 in 19.5%, 6 in 9.6%, 7 in 4%, 8 in 1.4%, 9 in 0.1% and 10 in 0.1%. Three months after uromune® 44.1% had 0 urinary tract infections and 27.6% had 1. After 6 months the results were 0 urinary tract infections in 32.3% and 1 in 32.4%. Women had 0 urinary tract infections after 3 months in 45.4% and 1 in 28.5%. At 6 months the female had 0 episodes in 32.7% and 1 in 33.2%. Menopausal women had 0 urinary tract infections at 3 months in 46.5% and 1 in 28% and at 6 months scored 0 episodes in 33.6% and 1 in 32.9%. CONCLUSIONS: Uromune® was highly effective to reduce the number of episodes of urinary tract infections at three and six months of follow-up. Uromune® reduced the number of episodes to zero or one in 71.7 and 64.7% at three and six months with minimal side effects. The best results were observed in women over 50 years old. Sublingual immunoprophylaxis with uromune® could be the treatment of first choice in the prevention of uncomplicated recurrent urinary tract infections according to the sample analyzed.

First experience in the UK of treating women with recurrent urinary tract infections with the bacterial vaccine Uromune®.

OBJECTIVES: To determine the effectiveness of Uromune® in preventing recurrent urinary tract infections (UTIs) in women. PATIENTS AND METHODS: A total of 77 women with microbiology-proven recurrent UTIs were given Uromune sublingual vaccine for a period of 3 months. Time to first UTI recurrence since treatment and adverse events were prospectively recorded in a follow-up period of up to 12 months. RESULTS: Of the 77 women, 75 completed the treatment. Of the 75 women who completed treatment, 59 (78%) had no subsequent UTIs in the follow-up period. Prior to treatment, all women had experienced a minimum of three or more episodes of UTI during the preceding 12 months. Proportionally, the majority of recurrences occurred in postmenopausal women. One patient had to stop treatment because of an adverse event (rash over face and neck). CONCLUSION: This prospective study suggests that Uromune is safe and effective at preventing UTIs in women. Further research is required in larger groups of patients for longer treatment times. An international double-blind randomized control trial comparing Uromune with placebo is currently underway.

Protective immunity induced by an intranasal multivalent vaccine comprising 10 Lactococcus lactis strains expressing highly prevalent M-protein antigens derived from Group A Streptococcus.

Streptococcus pyogenes (group A Streptococcus) causes diseases ranging from mild pharyngitis to severe invasive infections. The N-terminal fragment of streptococcal M protein elicits protective antibodies and is an attractive vaccine target. However, this N- terminal fragment is hypervariable: there are more than 200 different M types. In this study, an intranasal live bacterial vaccine comprising 10 strains of Lactococcus lactis, each expressing one N-terminal fragment of M protein, has been developed. Live bacterial-vectored vaccines cost less to manufacture because the processes involved are less complex than those required for production of protein subunit vaccines. Moreover, intranasal administration does not require syringes or specialized personnel. Evaluation of individual vaccine types (M1, M2, M3, M4, M6, M9, M12, M22, M28 and M77) showed that most of them protected mice against challenge with virulent S. pyogenes. All 10 strains combined in a 10-valent vaccine (M×10) induced serum and bronchoalveolar lavage IgG titers that ranged from three- to 10-fold those of unimmunized mice. After intranasal challenge with M28 streptococci, survival of M×10-immunized mice was significantly higher than that of unimmunized mice. In contrast, when mice were challenged with M75 streptococci, survival of M×10-immunized mice did not differ significantly from that of unimmunized mice. Mx-10 immunized mice had significantly less S. pyogenes in oropharyngeal washes and developed less severe disease symptoms after challenge than did unimmunized mice. Our L. lactis-based vaccine may provide an alternative solution to development of broadly protective group A streptococcal vaccines.

Preliminary report from the World Health Organisation Chest Radiography in Epidemiological Studies project.

Childhood pneumonia is among the leading infectious causes of mortality in children younger than 5 years of age globally. Streptococcus pneumoniae (pneumococcus) is the leading infectious cause of childhood bacterial pneumonia. The diagnosis of childhood pneumonia remains a critical epidemiological task for monitoring vaccine and treatment program effectiveness. The chest radiograph remains the most readily available and common imaging modality to assess childhood pneumonia. In 1997, the World Health Organization Radiology Working Group was established to provide a consensus method for the standardized definition for the interpretation of pediatric frontal chest radiographs, for use in bacterial vaccine efficacy trials in children. The definition was not designed for use in individual patient clinical management because of its emphasis on specificity at the expense of sensitivity. These definitions and endpoint conclusions were published in 2001 and an analysis of observer variation for these conclusions using a reference library of chest radiographs was published in 2005. In response to the technical needs identified through subsequent meetings, the World Health Organization Chest Radiography in Epidemiological Studies (CRES) project was initiated and is designed to be a continuation of the World Health Organization Radiology Working Group. The aims of the World Health Organization CRES project are to clarify the definitions used in the World Health Organization defined standardized interpretation of pediatric chest radiographs in bacterial vaccine impact and pneumonia epidemiological studies, reinforce the focus on reproducible chest radiograph readings, provide training and support with World Health Organization defined standardized interpretation of chest radiographs and develop guidelines and tools for investigators and site staff to assist in obtaining high-quality chest radiographs.

Modulating antibacterial immunity via bacterial membrane-coated nanoparticles.

Synthetic nanoparticles coated with cellular membranes have been increasingly explored to harness natural cell functions toward the development of novel therapeutic strategies. Herein, we report on a unique bacterial membrane-coated nanoparticle system as a new and exciting antibacterial vaccine. Using Escherichia coli as a model pathogen, we collect bacterial outer membrane vesicles (OMVs) and successfully coat them onto small gold nanoparticles (AuNPs) with a diameter of 30 nm. The resulting bacterial membrane-coated AuNPs (BM-AuNPs) show markedly enhanced stability in biological buffer solutions. When injected subcutaneously, the BM-AuNPs induce rapid activation and maturation of dendritic cells in the lymph nodes of the vaccinated mice. In addition, vaccination with BM-AuNPs generates antibody responses that are durable and of higher avidity than those elicited by OMVs only. The BM-AuNPs also induce an elevated production of interferon gamma (INFγ) and interleukin-17 (IL-17), but not interleukin-4 (IL-4), indicating its capability of generating strong Th1 and Th17 biased cell responses against the source bacteria. These observed results demonstrate that using natural bacterial membranes to coat synthetic nanoparticles holds great promise for designing effective antibacterial vaccines.

A controllable bacterial lysis system to enhance biological safety of live attenuated Vibrio anguillarum vaccine.

Bacterial strains used as backbone for the generation of vaccine prototypes should exhibit an adequate and stable safety profile. Given the fact that live attenuated vaccines often contain some potential risks in virulence recovery and spread infections, new approaches are greatly needed to improve their biological safety. Here, a critically iron-regulated promoter PviuA was screened from Vibrio anguillarum, which was demonstrated to respond to iron-limitation signal both in vitro and in vivo. By using PviuA as a regulatory switch to control the expression of phage P22 lysis cassette 13-19-15, a novel in vivo inducible bacterial lysis system was established in V. anguillarum. This system was proved to be activated by iron-limitation signals and then effectively lyse V. anguillarum both in vitro and in vivo. Further, this controllable bacterial lysis system, after being transformed into a live attenuated V. anguillarum vaccine strain MVAV6203, was confirmed to significantly improve biological safety of the live attenuated vaccine without impairing its immune protection efficacy.

Bacterial membrane vesicles combined with nanoparticles for bacterial vaccines and cancer immunotherapy.

Similar to mammalian cells, most bacteria can release nano-sized membrane vesicles (MVs) into the extracellular environment. MVs contain lipids, bioactive proteins, nucleic acids, and metabolites, and play important roles in microbial physiology. MVs have great potential for immunotherapeutic applications, such as bacterial vaccines and cancer immunotherapy. However, because of the diversity in content and heterogeneity in size of MVs, the clinical application of MVs has been limited. Recently, the use of MVs combined with nanoparticles (NPs) has been shown to be effective in improving the homogeneity, stability and function of MVs. In this review, we focus on studies of MVs combined with NPs (MV-NPs) and describe the use of these MV-NPs in biotechnology, especially in bacterial vaccine and cancer immunotherapy.

Queuing analysis for improving performance in bacterial vaccine quality control process.

The aim of the research is to analyze and improve the performance of the vaccine quality control queuing system to reduce delays and achieve the firm's long-term goal on vaccine production capacity. The research focuses on the Bacterial Vaccine Quality Control (BVQC) at the largest vaccine manufacturers in Indonesia and Southeast Asia. The vaccines handled by BVQC include TT, DTP, BCG, BioTT, BioTd, DT, Td, and DTP-Hb-Hib. The BVQC operates a queuing system with eight servers, each assigned a fixed task. The existing system experienced delays ranging from 13 % to 61 % from January to June 2022. After identifying the queuing characteristics of the existing system, improvement proposals were suggested by modifying the assignment of the servers. This proposal was then simulated in November 2022, resulting in improved performance with no delays, a reduction in the length of the queue in the system (Lq) from 2.88 to 2.59, and a reduction in the average time spent in the system (Ws) from 0.0099 to 0.0044. The research suggests that modifying server assignments can be an effective method for improving the performance of a queuing system in vaccine quality control. This can lead to reduced delays, optimized queue lengths, and improved overall efficiency, potentially enhancing the firm's ability to meet vaccine demand in the future.

An emerging antibacterial nanovaccine for enhanced chemotherapy by selectively eliminating tumor-colonizing bacteria.

Fusobacterium nucleatum (F. nucleatum), an oral anaerobe, is prevalent in colorectal cancer and is closely related to increased cancer cell growth, metastasis, and poor treatment outcomes. Bacterial vaccines capable of selectively eliminating bacteria present a promising approach to targeting intratumor F. nucleatum, thereby enhancing cancer treatment. Although adjuvants have been employed to enhance the immune response, the vaccine's effectiveness is constrained by inadequate T-cell activation necessary for eradicating intracellular pathogens. In this study, we developed a minimalistic, biomimetic nanovaccine by integrating highly immunostimulatory adjuvant cholesterol-modified CpG oligonucleotides into the autologously derived F. nucleatum membranes. Compared to the traditional vaccines consisting of inactivated bacteria and Alum adjuvant, the nanovaccine coupled with bacterial membranes and adjuvants could remarkably improve multiple antigens and adjuvant co-delivery to dendritic cells, maximizing their ability to achieve effective antigen presentation and strong downstream immune progress. Notably, the nanovaccine exhibits outstanding selective prophylactic and therapeutic effects, eliminating F. nucleatum without affecting intratumoral and gut microbiota. It significantly enhances chemotherapy efficacy and reduces cancer metastasis in F. nucleatum-infected colorectal cancer. Overall, this work represents the rational application of bacterial nanovaccine and provides a blueprint for future development in enhancing the antitumor effect against bacterial-infected cancer.

Comprehensive characterization of bacterial glycoconjugate vaccines by liquid chromatography - mass spectrometry.

Bacterial pathogens can cause a broad range of infections with detrimental effects on health. Vaccine development is essential as multi-drug resistance in bacterial infections is a rising concern. Recombinantly produced proteins carrying O-antigen glycosylation are promising glycoconjugate vaccine candidates to prevent bacterial infections. However, methods for their comprehensive structural characterization are lacking. Here, we present a bottom-up approach for their site-specific characterization, detecting N-glycopeptides by nano reversed-phase liquid chromatography-mass spectrometry (RP-LC-MS). Glycopeptide analyses revealed information on partial site-occupancy and site-specific glycosylation heterogeneity and helped corroborate the polysaccharide structures and their modifications. Bottom-up analysis was complemented by intact glycoprotein analysis using nano RP-LC-MS allowing the fast visualization of the polysaccharide distribution in the intact glycoconjugate. At the glycopeptide level, the model glycoconjugates analyzed showed different repeat unit (RU) distributions that spanned from 1 to 21 RUs attached to each of the different glycosylation sites. Interestingly, the intact glycoprotein analysis displayed a RU distribution ranging from 1 to 28 RUs, showing the predominant species when the different glycopeptide distributions are combined in the intact glycoconjugate. The complete workflow based on LC-MS measurements allows detailed and comprehensive analysis of the glycosylation state of glycoconjugate vaccines.

A review on the development of bacterial multi-epitope recombinant protein vaccines via reverse vaccinology.

Bacterial vaccines play a crucial role in combating bacterial infectious diseases. Apart from the prevention of disease, bacterial vaccines also help to reduce the mortality rates in infected populations. Advancements in vaccine development technologies have addressed the constraints of traditional vaccine design, providing novel approaches for the development of next-generation vaccines. Advancements in reverse vaccinology, bioinformatics, and comparative proteomics have opened horizons in vaccine development. Specifically, the use of protein structural data in crafting multi-epitope vaccines (MEVs) to target pathogens has become an important research focus in vaccinology. In this review, we focused on describing the methodologies and tools for epitope vaccine development, along with recent progress in this field. Moreover, this article also discusses the challenges in epitope vaccine development, providing insights for the future development of bacterial multi-epitope genetically engineered vaccines.

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.

Deep sequencing and variant frequency analysis for the quality control of a live bacterial vaccine against contagious bovine pleuropneumonia, strain T1.

Vaccination is the most cost-effective tool to control contagious bovine pleuropneumonia. The vaccines currently used in Africa are derived from a live strain called T1, which was attenuated by passage in embryonated eggs and broth culture. The number of passages is directly correlated to the degree of attenuation of the vaccinal strains and inversely correlated to their immunogenicity in cattle. Current quality control protocols applied to vaccine batches allow the assessment of identity, purity, and titers, but cannot assess the level of genetic drift form the parental vaccine strains. Deep sequencing was used to assess the genetic drift generated over controlled in vitro passages of the parental strain, as well as on commercial vaccine batches. Signatures of cloning procedures were detected in some batches, which imply a deviation from the standard production protocol. Deep sequencing is proposed as a new tool for the identity and stability control of T1 vaccines.

Investigation of a gel-based delivery method for the administration of a live, attenuated Salmonella Typhimurium vaccine.

Poultry vaccines are often administered using water as a suspension media and applied using an oral or coarse spray method. Gel-based vaccine diluents have been developed as an alternative vaccine delivery method. Gels are more viscous, and droplets adhere more effectively to feathers giving the vaccine a longer time to be ingested (through preening). Application of gel diluents with live bacterial vaccines, however, is limited. The present study tested a gel diluent prepared in various media, using a live, attenuated Salmonella Typhimurium vaccine, Vaxsafe ST. Reconstitution in gel diluent did not negatively affect vaccine viability or motility. The invasive capacity of vaccine suspended in gel diluent into cultured intestinal epithelial cells was also tested. Results demonstrated that vaccine suspended in gel diluent retained invasiveness. Day old chicks were orally administered with Vaxsafe ST suspended in gel diluent to characterize in vivo colonization capacity of the vaccine. The results revealed that the VaxSafe ST suspended in gel diluent could efficiently colonize the caeca of chicks, which is needed for the development of effective immunity.

A simple method for enrichment of phase I Coxiella burnetii.

Coxiella burnetii is the bacterial causative agent of the zoonosis Q fever. This bacterium undergoes lipopolysaccharide (LPS) phase transition similar to Enterobacteriaciae upon in vitro passage. Full-length, phase I C. burnetii LPS is a critical virulence factor and profoundly impacts vaccine-induced immunogenicity; thus, LPS phase is an important consideration in C. burnetii experimentation and Q fever vaccine design. Typically, phase I LPS-expressing organisms are obtained from the tissues of infected experimental animals. In this process, residual phase II LPS-expressing organisms are thought to be cleared by the host immune system. Here, we propose an efficient and non-animal-based method for the enrichment of C. burnetii phase I LPS-expressing bacteria in vitro. We utilize both Vero cell culture to selectively enrich solutions with phase I and intermediate phase LPS-expressing bacteria. This simple and quick method decreases reliance on experimental animals and is a sustainable solution for Q fever diagnostic and vaccine development hurdles.

Cell membrane-coated nanoparticles for the treatment of bacterial infection.

Despite the enormous success of antibiotics in antimicrobial therapy, the rapid emergence of antibiotic resistance and the complexity of the bacterial infection microenvironment make traditional antibiotic therapy face critical challenges against resistant bacteria, antitoxin, and intracellular infections. Consequently, there is a critical need to design antimicrobial agents that target infection microenvironment and alleviate antibiotic resistance. Cell membrane-coated nanoparticles (CMCNPs) are biomimetic materials that can be obtained by wrapping the cell membrane vesicles directly onto the surface of the nanoparticles (NPs) through physical means. Incorporating the biological functions of cell membrane vesicles and the superior physicochemical properties of NPs, CMCNPs have shown great promise in recent years for targeting infections, neutralizing bacterial toxins, and designing bacterial infection vaccines. This review highlights topics where CMCNPs present great value in advancing the treatment of bacterial infections, including drug delivery, detoxification, and vaccination. Lastly, we discuss the future hurdles and prospects of translating this technique into clinical practice, providing a comprehensive review of the technological developments of CMCNPs in the treatment of bacterial infections. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Preclinical Animal Models for Q Fever Vaccine Development.

Coxiella burnetii is a zoonotic pathogen responsible for the human disease Q fever. While an inactivated whole cell vaccine exists for this disease, its widespread use is precluded by a post vaccination hypersensitivity response. Efforts for the development of an improved Q fever vaccine are intricately connected to the availability of appropriate animal models of human disease. Accordingly, small mammals and non-human primates have been utilized for vaccine-challenge and post vaccination hypersensitivity modeling. Here, we review the animal models historically utilized in Q fever vaccine development, describe recent advances in this area, discuss the limitations and strengths of these models, and summarize the needs and criteria for future modeling efforts. In summary, while many useful models for Q fever vaccine development exist, there remains room for growth and expansion of these models which will in turn increase our understanding of C. burnetii host interactions.

Low-Energy Electron Irradiation (LEEI) for the Generation of Inactivated Bacterial Vaccines.

Vaccines consisting of whole inactivated bacteria (bacterins) are generated by incubation of the pathogen with chemicals. This is a time-consuming procedure which may lead to less immunogenic material, as critical antigenic structures can be altered by chemical modification. A promising alternative approach is low-energy electron irradiation (LEEI). Like other types of ionizing radiation, it mainly acts by destroying nucleic acids but causes less damage to structural components like proteins. As the electrons have a limited penetration depth, LEEI is currently used for sterilization of surfaces. The inactivation of pathogens in liquids requires irradiation of the culture in a thin film to ensure complete penetration. Here, we describe two approaches for the irradiation of bacterial suspensions in a research scale. After confirmation of inactivation, the material can be directly used for vaccination, without any purification steps.