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.

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.

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.

Enhancing innate immunity against virus in times of COVID-19: Trying to untangle facts from fictions

Introduction

In light of the current COVID-19 pandemic, during which the world is confronted with a new, highly contagious virus that suppresses innate immunity as one of its initial virulence mechanisms, thus escaping from first-line human defense mechanisms, enhancing innate immunity seems a good preventive strategy.

Methods

Without the intention to write an official systematic review, but more to give an overview of possible strategies, in this review article we discuss several interventions that might stimulate innate immunity and thus our defense against (viral) respiratory tract infections. Some of these interventions can also stimulate the adaptive T- and B-cell responses, but our main focus is on the innate part of immunity. We divide the reviewed interventions into: 1) lifestyle related (exercise, >7 h sleep, forest walking, meditation/mindfulness, vitamin supplementation); 2) Non-specific immune stimulants (letting fever advance, bacterial vaccines, probiotics, dialyzable leukocyte extract, pidotimod), and 3) specific vaccines with heterologous effect (BCG vaccine, mumps-measles-rubeola vaccine, etc).

Results

For each of these interventions we briefly comment on their definition, possible mechanisms and evidence of clinical efficacy or lack of it, especially focusing on respiratory tract infections, viral infections, and eventually a reduced mortality in severe respiratory infections in the intensive care unit. At the end, a summary table demonstrates the best trials supporting (or not) clinical evidence.

Conclusion

Several interventions have some degree of evidence for enhancing the innate immune response and thus conveying possible benefit, but specific trials in COVID-19 should be conducted to support solid recommendations.

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.

Evaluation of a biodegradable microparticulate polymer as a carrier for Burkholderia pseudomallei subunit vaccines in a mouse model of melioidosis

Melioidosis, a potentially lethal disease of humans and animals, is caused by the soil-dwelling bacterium Burkholderia pseudomallei. Due to B. pseudomallei's classification as a Tier 1 Select Agent, there is substantial interest in the development of an effective vaccine. Yet, despite decades of research, no effective target, adjuvant or delivery vehicle capable of inducing protective immunity against B. pseudomallei infection has been identified. We propose a microparticulate delivery vehicle comprised of the novel polymer acetalated dextran (Ac-DEX). Ac-DEX is an acid-sensitive biodegradable carrier that can be fabricated into microparticles (MPs) that are relatively stable at pH 7.4, but rapidly degrade after phagocytosis by antigen presenting cells where the pH can drop to 5.0. As compared to other biomaterials, this acid sensitivity has been shown to enhance cross presentation of subunit antigens. To evaluate this platform as a delivery system for a melioidosis vaccine, BALB/c mice were vaccinated with Ac-DEX MPs separately encapsulating B. pseudomallei whole cell lysate and the toll-like receptor (TLR) 7/8 agonist resiquimod. This vaccine elicited a robust antibody response that included both Th1 and Th2 immunity. Following lethal intraperitoneal challenge with B. pseudomallei 1026b, vaccinated mice demonstrated a significant delay to time of death compared to untreated mice. The formulation, however, demonstrated incomplete protection indicating that lysate protein offers limited value as an antigen. Nevertheless, our Ac-DEX MPs may offer an effective delivery vehicle for a subunit B. psuedomallei vaccine.