Method for quantifying the Pasteurella multocida antigen adsorbed on aluminum hydroxide adjuvant in swine atrophic rhinitis vaccine.

Swine atrophic rhinitis is a disease caused by Pasteurella multocida and Bordetella bronchiseptica that affects pigs. Inactivated vaccines containing the toxins produced by Pasteurella multocida and Bordetella bronchiseptica have been widely used for the prevention of swine atrophic rhinitis. The efficacy of a vaccine is correlated with the amount of antigen present; however, the protective toxin of P. multocida bound to aluminum hydroxide, which is used as an adjuvant, can hinder the monitoring of the antigen concentration in the vaccine. This study assessed the applicability of a dot immunoassay as an antigen quantification method using monoclonal antibodies. This quantification method was able to detect the antigen with high specificity and sensitivity even when the antigen was bound to the adjuvant, and its application to vaccine products revealed a correlation between the amount of antigen present in the vaccine and the neutralizing antibody titers induced in pigs. The antigen quantification method presented in this study is a simple and sensitive assay capable of quantifying the amount of antigen present in a vaccine that can be used as an alternative quality control measure.

Induction of antitoxic antibody and preventive effect against porcine edema disease by the pentameric Stx2eB subunit vaccine.

Porcine edema disease (ED) is an enterotoxaemia that frequently occurs in 4-12 week-old piglets and results in high mortality. ED is caused by Shiga toxin 2e (Stx2e), produced by host-adapted Shiga toxin-producing Escherichia coli (STEC) strains. We constructed a recombinant protein in which the B subunit of Stx2e (Stx2eB) was linked to Cartilage Oligomeric Matrix Protein (COMP)'s pentameric domain to enhance antigenicity to induce neutralizing antibodies against Stx2e. We evaluated the efficacy of this antigen as a vaccine on the farm where ED had occurred. The suckling piglets were divided into two groups. The pigs in the vaccinated group were intramuscularly immunized with the vaccine containing 30 µg/head of Stx2eB-COMP at 1 and 4 weeks of age. The control pigs were injected with saline instead of the vaccine. The neutralizing antibody titer to Stx2e, mortality, clinical score, and body weight was evaluated up to 11 weeks after the first vaccination. In the vaccinated group, the Stx2e neutralizing antibody was detected 3 weeks after the first vaccination, its titer increased during the following weeks. The antibody was not detected in the control group during the test period. The STEC gene was detected in both groups during the test period, but a typical ED was observed only in control pigs; the mortality and clinical score were significantly lower in the vaccinated group than in the control group. These data indicate that the pentameric B subunit vaccine is effective for preventing ED and offers a promising tool for pig health control.

Efficacy and safety of vonoprazan-based regimen for Helicobacter pylori eradication therapy in Japanese adolescents: a prospective multicenter study.

BACKGROUND: Vonoprazan (VPZ)-based regimen for Helicobacter pylori (H. pylori) is safe and more efficacious than the proton pump inhibitor-based regimen mainly in adults. This study aimed to evaluate the efficacy and safety of a VPZ-based regimen for H. pylori eradication therapy in adolescents. METHODS: An H. pylori screening and treatment longitudinal project for third-year junior high school students in Saga Prefecture began in 2016. Students who tested positive for both urine and stool tests received a VPZ-based regimen. On the checklist, students were asked for diarrhea, fever, abdominal pain, nausea, vomiting, urticaria, dysgeusia, or bloody stool occurrence during the therapy. RESULTS: The longitudinal project for H. pylori screening and treatment among third-grade students in Saga Prefecture targeted 41,115 students from 2017 to 2021 and 836 as positive. Of the 645 students, 542 (84.0% in per protocol [PP] analysis and 73.6% in intention-to-treat [ITT] analysis) were successful in primary eradication therapy. The secondary eradication therapy was successful in 79 (96.3% in PP analysis and 76.7% in ITT analysis) of 82 students. In the primary eradication therapy, abdominal pain occurred in 164 (27.9%), diarrhea in 217 (36.9%), nausea or vomiting in 7 (1.2%), and urticaria in 13 (2.2%) students. In the secondary eradication therapy, abdominal pain occurred in 12 (19.4%) and diarrhea in 17 (27.4%) students. The eradication therapy of 5 students was interrupted due to adverse events only by primary eradication therapy. CONCLUSIONS: VPZ-based regimen for H. pylori was efficacious and safe for adolescents, as in adults, for both primary and secondary eradication therapies.

Persistence of neutralizing antibody and its protective efficacy induced by a live attenuated tetravalent dengue vaccine, KD-382, in cynomolgus monkeys.

An effective dengue vaccine should induce a long-lasting immune response against all four serotypes simultaneously with a minimum number of immunizations. Our live attenuated tetravalent dengue vaccine candidate, KD-382, was developed using a classical host range mutation strategy (no addition of artificial genetic modification). In our previous study, cynomolgus monkeys immunized with a single dose of KD-382 seroconverted to all four serotypes. However, it is important to determine if neutralizing antibodies (NAbs) induced by KD-382 can work as a long-lasting immune response to prevent dengue. In this study, a single dose of KD-382 induced a strong NAb response against all four serotypes in cynomolgus monkeys. We also confirmed that NAb titers against all four serotypes persist for at least five years, indicating its high potential as a dengue vaccine candidate. Next, we evaluated the effect of pre-existing dengue immunity on NAb responses induced by KD-382. We administered KD-382 to cynomolgus monkeys pre-administered one of the monovalent parental wild-type strains 60 days before vaccination. Regardless of the pre-immunized serotype, all the monkeys showed sufficient tetravalent NAb responses, which lasted for over two years. All the KD-382 vaccinated monkeys were then challenged with different parental wild-type viruses than that used for pre-administration; viral RNA in the serum was less than the lower limit of quantification, indicating complete protection against secondary heterologous dengue infection without any harmful disease enhancement. Consequently, KD-382 successfully induced a long-lasting and protective tetravalent NAb response in monkeys, suggesting that KD-382 is a promising vaccine candidate usable for both dengue seronegative and seropositive individuals.

Gastrointestinal adverse reactions reduce the success rate of Helicobacter pylori eradication therapy: A multicenter prospective cohort study.

BACKGROUND: The screening and treatment of Helicobacter pylori infection for all junior high students in Saga Prefecture, Japan, were started in 2016. The present study aims to evaluate the influence of adverse reactions on the success of the eradication therapy. METHODS: From 2017 to 2019, 25,006 third-grade junior high school students were tested for urinary anti-H. pylori antibodies. Positive cases were confirmed by H. pylori stool antigen tests. Of the 531 students who were found to be H. pylori-positive, 390 (358 in first-line and 32 in second-line therapy) underwent eradication therapy, and 274 (242 in first-line and 32 in second-line) students actually completed a self-reported form to rate stool consistency (based on the Bristol Stool Scale), the maximum number of bowel movements, and abdominal symptoms during the 7 days of treatment. RESULTS: Among the 274 students, the total of primary and secondary eradication success rates was 87% (95% confidential interval: 82.9-90.1) in intention-to-treat analysis. On days 4, 5, and 6, stool consistency was looser in the primary eradication failure group than in the success group (p < .05). Looser stool consistencies were observed in male students with abdominal pain compared to those who did not experience pain (p < .05). Abdominal pain and diarrhea were detected in 28.5% and 42.7% of the subjects, respectively. The overall incidence of other adverse events was low (n = 8/274, 2.9%), and only two students discontinued treatment because of adverse events. CONCLUSIONS: Softening of the stool was related to the eradication failure in the junior high school students, especially in males with abdominal pain. Adverse effects did not induce discontinuation of the eradication treatment.

Well-balanced immune response and protective efficacy induced by a single dose of live attenuated tetravalent dengue vaccine (KD-382) in monkeys.

One of the challenges developing a live attenuated tetravalent dengue vaccine (TDV) is to overcome the presumed viral interference that may be preventing the induction of a balanced immune response to all 4 serotypes of the dengue virus (DENV1-4). Our live attenuated TDV candidate was developed from wild-type (wt) parental strains (DENV1/03135, DENV2/99345, DENV3/16562, and DENV4/1036, respectively) using a classical host range mutation strategy: the same strategy used for the approved live attenuated smallpox, polio, and MMR vaccines. Our vaccine candidate is expected to mimic natural dengue virus infection, as it provides all the components of dengue virus, including both structural and nonstructural proteins. Therefore, induction of more solid and comprehensive immune responses against pathogenic dengue viruses is also expected. In this study, we evaluated the neutralizing antibody responses for each serotype induced by a single subcutaneous administration of 6 formulations, which were composed of different combinations of vaccine strains and were all of different dosages. These formulations were tested in dengue-naïve cynomolgus macaques. As a result, regardless of the TDV formulation, all the monkeys immunized with TDVs seroconverted to all the 4 serotypes at day 30. Next, we evaluated protection ability of the selected formulations of TDV candidate, no RNAemia was detected from any of the immunized monkeys upon s.c. challenge with wtDENV. The findings of this non-human primate study indicate that our vaccine candidate is very promising; it can be further evaluated for safety and efficacy in human clinical studies.

High-risk populations for nasal carriage of methicillin-resistant Staphylococcus aureus.

To determine the population at high risk of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) on hospital patients admission, a nasal swab was taken from the following patients: (1) those aged 70 years or over (age >or= 70), (2) non ambulatory receiving regular home visits by nurses and physicians (visiting), (3) residents of nursing homes (nursing home), (4) patients from other hospitals (another Hp), and (5) those scheduled for surgery (presurgery). Between March and July 2000, a total of 412 patients were admitted and 136 were enrolled. MRSA was isolated from 12 (8.8%) patients. The number of patients positive for MRSA in the five groups, age >or=70, visiting, nursing home, another Hp, and presurgery, were 3 of 68, 3 of 21, 2 of 3, 3 of 9, and 1 of 35, respectively. Multivariate analysis revealed that living in a nursing home [odds ratio (OR) = 32.82, P = 0.010] or coming from another hospital (OR = 14.55, P = 0.0043) were high risk factors with for nasal carriage of MRSA. Furthermore, patients' ages were further divided into three categories, or=90, and regarded as independent high risk factors (OR = 3.08, P = 0.043). The results were that advanced living in a age (>or=80, >or=90), living in a nursing home or coming from another hospital are high risk factors of nasal carriage of MRSA on hospital admission.

A case of acute gastric mucosal lesions associated with Helicobacter heilmannii infection.

A 69-year-old-woman presented with acute epigastric pain, nausea, vomiting and heartburn. Endoscopy disclosed acute gastric mucosal lesions including mucosal edema, erosions, and ulcers with blood crusts in the antrum. Touch cytology and histological assessment obtained from the affected mucosa revealed acute neutrophilic gastritis and single longer and more coiled organisms than Helicobacter pylori, suggesting Helicobacter heilmannii. Electron micropragh confirmed the characteristic morphology. Despite a positive rapid urease test, H. pylori was not isolated by culture or detected by histology and Gram smears. Based on these findings, a diagnosis of acute gastric mucosal lesions associated with H. heilmannii infection was established. This was successfully treated with a 2-week triple therapy consisting of lansoprazole, clarithromycin and metronidazole with persistent endoscopic and histological remission. This is a rare case of H. heilmannii-associated acute gastric mucosal lesions, diagnosed by morphology using touch cytology and histology. The patient might benefit from antimicrobial treatment employing the regimen effective for H. pylori.

Influence of Helicobacter pylori infection on in vitro responsiveness of gastric fundus to agonists and to stimulation of enteric nerves in Mongolian gerbils.

BACKGROUND: It has recently been proposed that disturbed gastric adaptive relaxation may play a role in functional dyspepsia (FD). However, the effect of Helicobacter pylori infection, which may be one of multiple factors associated with FD, on gastric relaxation is not clear. The aim of this study was to clarify the influence of H. pylori infection on the responsiveness of smooth muscles of the gastric fundus to agonists or to stimulation of enteric nerves, with particular emphasis on nonadrenergic noncholinergic (NANC) relaxation. METHODS: We investigated myogenic responses to carbachol (CCH) and sodium nitroprusside (SNP), and neural responses to electrical field stimulation (EFS), in the absence or presence of atropine and guanethidine, in the tissues of the gastric fundus of H. pylori-infected Mongolian gerbils (MGs). RESULTS: H. pylori-infected MGs showed typical gastritis, with H. pylori colonization in the antrum and body. The gastric fundus adjacent to the body was composed of thin gastric mucosa with mild inflammation, which was covered with stratified squamous epithelium, and the muscle layer communicated with that of the gastric body. In the gastric fundus, CCH- and SNP-induced responses were not different in controls and H. pylori-infected MGs. In the absence of any antagonists, EFS-evoked contraction tended to be reduced in H. pylori-infected MGs compared with that in control MGs, albeit that the difference was statistically nonsignificant. N(omega)-nitro- l-arginine methyl ester inhibited NANC relaxation in the tissues in both groups. EFS-evoked NANC relaxation remained intact in H. pylori-infected MGs. CONCLUSIONS: Mild inflammation in gastric fundus associated with H. pylori infection does not cause enteric neuromuscular dysfunction of the site in vitro.