Changes in capsular serotype alter the surface exposure of pneumococcal adhesins and impact virulence

We examined the contribution of serotype on Streptococcus pneumoniae adhesion and virulence during respiratory tract infection using a panel of isogenic TIGR4 (serotype 4) mutants expressing the capsule types 6A (+6A), 7F (+7F) and 23F (+23F) as well as a deleted and restored serotype 4 (+4) control strain. Immunoblots, bacterial capture assays with immobilized antibody, and measurement of mean fluorescent intensity by flow cytometry following incubation of bacteria with antibody, all determined that the surface accessibility, but not total protein levels, of the virulence determinants Pneumococcal surface protein A (PspA), Choline binding protein A (CbpA), and Pneumococcal serine-rich repeat protein (PsrP) changed with serotype. In vitro, bacterial adhesion to Detroit 562 pharyngeal or A549 lung epithelial cells was modestly but significantly altered for +6A, +7F and +23F. In a mouse model of nasopharyngeal colonization, the number of +6A, +7F, and +23F pneumococci in the nasopharynx was reduced 10 to 100-fold versus +4; notably, only mice challenged with +4 developed bacteremia. Intratracheal challenge of mice confirmed that capsule switch strains were highly attenuated for virulence. Compared to +4, the +6A, +7F, and +23F strains were rapidly cleared from the lungs and were not detected in the blood. In mice challenged intraperitoneally, a marked reduction in bacterial blood titers was observed for those challenged with +6A and +7F versus +4 and +23F was undetectable. These findings show that serotype impacts the accessibility of surface adhesins and, in particular, affects virulence within the respiratory tract. They highlight the complex interplay between capsule and protein virulence determinants

Recombinant plants provide a new approach to the production of bacterial polysaccharide for vaccines

Bacterial polysaccharides have numerous clinical or industrial uses. Recombinant plants could offer the possibility of producing bacterial polysaccharides on a large scale and free of contaminating bacterial toxins and antigens. We investigated the feasibility of this proposal by cloning and expressing the gene for the type 3 synthase (cps3S) of Streptococcus pneumoniae in Nicotinia tabacum, using the pCambia2301 vector and Agrobacterium tumefaciens-mediated gene transfer. In planta the recombinant synthase polymerised plant-derived UDP-glucose and UDP-glucuronic acid to form type 3 polysaccharide. Expression of the cps3S gene was detected by RT-PCR and production of the pneumococcal polysaccharide was detected in tobacco leaf extracts by double immunodiffusion, Western blotting and high-voltage paper electrophoresis. Because it is used a component of anti-pneumococcal vaccines, the immunogenicity of the plant-derived type 3 polysaccharide was tested. Mice immunised with extracts from recombinant plants were protected from challenge with a lethal dose of pneumococci in a model of pneumonia and the immunised mice had significantly elevated levels of serum anti-pneumococcal polysaccharide antibodies. This study provides the proof of the principle that bacterial polysaccharide can be successfully synthesised in plants and that these recombinant polysaccharides could be used as vaccines to protect against life-threatening infections

The financial burden of psychosocial workplace aggression: a systematic review of cost-of-illness studies

Understanding the economic impact of psychological and social forms of workplace aggression to society could yield important insights into the magnitude of this occupational phenomenon. The objective of this systematic review was to collate, summarize, review and critique, and synthesize the cost of psychosocial workplace aggression at the individual- and societal-level. A peer-reviewed research protocol detailing the search strategy, study selection procedures and data extraction process was developed a priori. Both the academic and grey literatures were examined. To allow for basic comparison, all costs were converted and adjusted to reflect 2014 US dollars. Twelve studies, from five national contexts, met the inclusion criteria and were reviewed: Australia (n=2), Italy (n=1), Spain (n=1), the United Kingdom (n=3) and the United States (n=5). The annual cost of psychosocial workplace aggression varied substantially, ranging between $114.64 million and$35.9 billion. Heterogeneity across studies was found, with noted variations in stated study aims, utilized prevalence statistics and included costs. The review concludes that existing evidence attests to the substantial cost of psychosocial workplace aggression to both the individual and society, albeit such derived estimates are likely gross underestimates. The findings highlight the importance of interpreting such figures within their conceptual and methodological contexts

Spontaneous bladder rupture diagnosis based on urinary appearance of mesothelial cells: a case report

Introduction. Spontaneous bladder rupture is an extremely rare clinical event that is associated with urinary ascites and apparent acute renal failure. This event is difficult to diagnose clinically, even with advanced techniques such as computed tomography; however, the timely diagnosis of this condition is critical. Here, we report a case of a patient who experienced a spontaneous intraperitoneal bladder rupture 10 years after postoperative pelvic irradiation for the treatment of uterine cancer. In this report of a rare case, we describe the contribution of the appearance of mesothelial cells in the urine to the diagnosis of this condition. Case presentation. Our patient was a 71-year-old Asian woman who experienced lower abdominal pain and vomiting of two days duration. On admission, abdominal computed tomography showed intraperitoneal fluid collection and her blood tests revealed acute renal failure and hyperkalemia. She underwent hemodialysis and a transurethral catheter was inserted. The transurethral catheter was removed three days after her admission. Four days after the catheter removal, her symptoms recurred and her serum creatinine and blood urea nitrogen levels were elevated. We noted the presence of mesothelial cells in her urine, which led to a diagnosis of intraperitoneal bladder rupture. She underwent surgical repair of her bladder and hyperbaric oxygen therapy, and was discharged after her renal function returned to normal. Conclusion: Urine analysis is a simple and non-invasive test and we believe that a thorough urine analysis may contribute to the early diagnosis of an intraperitoneal bladder rupture. We think that the findings presented in this case report will significantly enhance our understanding of the etiology of bladder rupture. Moreover, these case findings may help nephrologists and urologists to rapidly diagnose this condition

Progress in mucosal immunization for protection against pneumococcal pneumonia

Introduction: Lower respiratory tract infections are the fourth cause of death worldwide and pneumococcus is the leading cause of pneumonia. Nonetheless, existing pneumococcal vaccines are less effective against pneumonia than invasive diseases and serotype replacement is a major concern. Protein antigens could induce serotype-independent protection, and mucosal immunization could offer local and systemic immune responses and induce protection against pneumococcal colonization and lung infection. Areas covered: Immunity induced in the experimental human pneumococcal carriage model, approaches to address the physiological barriers to mucosal immunization and improve delivery of the vaccine antigens, different strategies already tested for pneumococcal mucosal vaccination, including live recombinant bacteria, nanoparticles, bacterium-like particles, and nanogels as well as, nasal, pulmonary, sublingual and oral routes of vaccination. Expert opinion: The most promising delivery systems are based on nanoparticles, bacterial-like particles or nanogels, which possess greater immunogenicity than the antigen alone and are considered safer than approaches based on living cells or toxoids. These particles can protect the antigen from degradation, eliminating the refrigeration need during storage and allowing the manufacture of dry powder formulations. They can also increase antigen uptake, control release of antigen and trigger innate immune responses

Cross-Protective Peptide Vaccine against Influenza A Viruses Developed in HLA-A*2402 Human Immunity Model

Background: The virus-specific cytotoxic T lymphocyte (CTL) induction is an important target for the development of a broadly protective human influenza vaccine, since most CTL epitopes are found on internal viral proteins and relatively conserved. In this study, the possibility of developing a strain/subtype-independent human influenza vaccine was explored by taking a bioinformatics approach to establish an immunogenic HLA-A24 restricted CTL epitope screening system in HLAtransgenic mice. Methodology/Principal Findings: HLA-A24 restricted CTL epitope peptides derived from internal proteins of the H5N1 highly pathogenic avian influenza A virus were predicted by CTL epitope peptide prediction programs. Of 35 predicted peptides, six peptides exhibited remarkable cytotoxic activity in vivo. More than half of the mice which were subcutaneously vaccinated with the three most immunogenic and highly conserved epitopes among three different influenza A virus subtypes (H1N1, H3N2 and H5N1) survived lethal influenza virus challenge during both effector and memory CTL phases. Furthermore, mice that were intranasally vaccinated with these peptides remained free of clinical signs after lethal virus challenge during the effector phase. Conclusions/Significance: This CTL epitope peptide selection system can be used as an effective tool for the development of a cross-protective human influenza vaccine. Furthermore this vaccine strategy can be applicable to the development o