A chimeric protein-based vaccine elicits a strong IgG antibody response and confers partial protection against Shiga toxin-producing Escherichia coli in mice.

Background: Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen that causes gastrointestinal infections, ranging from acute diarrhea and dysentery to life-threatening diseases such as Hemolytic Uremic Syndrome. Currently, a vaccine to prevent STEC infection is an unmet medical need. Results: We developed a chimeric protein-based vaccine targeting seven virulence factors of STEC, including the Stx2B subunit, Tir, Intimin, EspA, Cah, OmpT, and AggA proteins. Immunization of mice with this vaccine candidate elicited significant humoral and cellular immune responses against STEC. High levels of specific IgG antibodies were found in the serum and feces of immunized mice. However, specific IgA antibodies were not detected in either serum or feces. Furthermore, a significantly higher percentage of antigen-specific CD4+ T cells producing IFN-γ, IL-4, and IL-17 was observed in the spleens of immunized mice. Notably, the immunized mice showed decreased shedding of STEC O157:H7 and STEC O91:H21 strains and were protected against weight loss during experimental infection. Additionally, infection with the STEC O91:H21 strain resulted in kidney damage in control unimmunized mice; however, the extent of damage was slightly lower in immunized mice. Our findings suggest that IgG antibodies induced by this vaccine candidate may have a role in inhibiting bacterial adhesion and complement-mediated killing. Conclusion: This study provides evidence that IgG responses are involved in the host defense against STEC. However, our results do not rule out that other classes of antibodies also participate in the protection against this pathogen. Additional work is needed to improve the protection conferred by our vaccine candidate and to elucidate the relevant immune responses that lead to complete protection against this pathogen.

Vibrio cholerae, classification, pathogenesis, immune response, and trends in vaccine development.

Vibrio cholerae is the causative agent of cholera, a highly contagious diarrheal disease affecting millions worldwide each year. Cholera is a major public health problem, primarily in countries with poor sanitary conditions and regions affected by natural disasters, where access to safe drinking water is limited. In this narrative review, we aim to summarize the current understanding of the evolution of virulence and pathogenesis of V. cholerae as well as provide an overview of the immune response against this pathogen. We highlight that V. cholerae has a remarkable ability to adapt and evolve, which is a global concern because it increases the risk of cholera outbreaks and the spread of the disease to new regions, making its control even more challenging. Furthermore, we show that this pathogen expresses several virulence factors enabling it to efficiently colonize the human intestine and cause cholera. A cumulative body of work also shows that V. cholerae infection triggers an inflammatory response that influences the development of immune memory against cholera. Lastly, we reviewed the status of licensed cholera vaccines, those undergoing clinical evaluation, and recent progress in developing next-generation vaccines. This review offers a comprehensive view of V. cholerae and identifies knowledge gaps that must be addressed to develop more effective cholera vaccines.

Two centuries of vaccination: historical and conceptual approach and future perspectives.

Over the past two centuries, vaccines have been critical for the prevention of infectious diseases and are considered milestones in the medical and public health history. The World Health Organization estimates that vaccination currently prevents approximately 3.5-5 million deaths annually, attributed to diseases such as diphtheria, tetanus, pertussis, influenza, and measles. Vaccination has been instrumental in eradicating important pathogens, including the smallpox virus and wild poliovirus types 2 and 3. This narrative review offers a detailed journey through the history and advancements in vaccinology, tailored for healthcare workers. It traces pivotal milestones, beginning with the variolation practices in the early 17th century, the development of the first smallpox vaccine, and the continuous evolution and innovation in vaccine development up to the present day. We also briefly review immunological principles underlying vaccination, as well as the main vaccine types, with a special mention of the recently introduced mRNA vaccine technology. Additionally, we discuss the broad benefits of vaccines, including their role in reducing morbidity and mortality, and in fostering socioeconomic development in communities. Finally, we address the issue of vaccine hesitancy and discuss effective strategies to promote vaccine acceptance. Research, collaboration, and the widespread acceptance and use of vaccines are imperative for the continued success of vaccination programs in controlling and ultimately eradicating infectious diseases.

Seasonal droughts during the Miocene drove the evolution of Capparaceae towards Neotropical seasonally dry forests / Las sequías estacionales del Mioceno impulsaron la evolución de Capparaceae hacia los bosques neotropicales estacionalmente secos

Abstract Introduction: Neotropical seasonally dry forest (NSDF) climatic constraints increased endemism, and phylogenetic niche conservatism in species that are restricted to this biome. NSDF have a large number of endemic Capparaceae taxa, but it is unknown if phylogenetic niche conservatism has played a role in this pattern. Objective: We carried out an evolutionary analysis of the climatic niche of neotropical species of Capparaceae to identify whether the climatic constraints of NSDF have played a major role throughout the family's evolutionary history. Methods: Using three chloroplastic (ndhF, matK, rbcL) and one ribosomal (rsp3) DNA sequences, we proposed a date phylogeny to reconstruct the evolutionary climatic niche dynamics of 24 Neotropical species of Capparaceae. We tested the relationship between niche dissimilarity and phylogenetic distance between species using the Mantel test. Likewise, we used a set of phylogenetic comparative methods (PGLS) on the phylogeny of Capparaceae to reconstruct the main evolutionary historic events in their niche. Results: Capparaceae originated in humid regions and subsequently, convergent evolution occurred towards humid and dry forest during the aridification phases of the Middle Miocene (16-11 Mya). However, adaptation towards drought stress was reflected only during the precipitation of the coldest quarter, where we found phylogenetic signal (Pagel λ) for gradual evolution and, therefore, evidence of phylogenetic niche conservatism. We found convergent species-specific adaptations to both drought stress and rainfall during the Miocene, suggesting a non-phylogenetic structure in most climatic variables. Conclusions: Our study shows how the Miocene climate may have influenced the Capparaceae speciation toward driest environments. Further, highlights the complexity of climatic niche dynamics in this family, and therefore more detailed analyses are necessary in order to better understand the NSDF climatic constrictions affected the evolution of Capparaceae.

Resumen Introducción: Las limitaciones climáticas del bosque neotropical estacionalmente seco (NSDF) produjeron endemismo y conservadurismo filogenético del nicho en especies restringidas a este bosque. En las Caparáceas neotropicales se ha encontrado endemismo en los NSDF, pero se desconoce si el conservadurismo de nicho filogenético ha influido en su evolución. Objetivos: Se llevó a cabo un análisis evolutivo del nicho climático de las especies neotropicales de Capparaceae para evaluar si las limitaciones climáticas del bosque neotropical estacionalmente seco (NSDF) han jugado un papel importante a lo largo de la historia evolutiva de la familia. Métodos: Usando tres secuencias de ADN cloroplastico (ndhF, matK, rbcL) y una ribosomal (rsp3) se propuso una filogenia datada para reconstruir la dinámica evolutiva del nicho climático de 24 especies Neotropicales de Capparaceae. Utilizando la prueba de Mantel, se realizaron análisis para establecer si hay diferencia de nicho y la distancia filogenética entre especies. Asimismo, se emplearon un conjunto de métodos comparativos filogenéticos sobre la filogenia de la familia para reconstruir los principales eventos históricos evolutivos en su nicho. Resultados: Capparaceae se originó en regiones húmedas y posteriormente se dio una evolución convergente hacia bosque húmedo y seco durante las fases de aridificación del Mioceno Medio (16-11 Ma). Sin embargo, la adaptación al estrés por sequía se reflejó solo en la precipitación del cuarto más frío del año, donde se evidencio señal filogenética, evolución gradual y, por lo tanto, evidencia de conservadurismo de nicho filogenético. También se hallaron especies con adaptaciones convergentes específicas tanto al estrés por sequía como a las lluvias durante el Mioceno, sugiriendo la carencia de estructura filogenética en la mayoría de las variables climáticas. Conclusiones: Este estudio muestra cómo el clima del Mioceno pudo haber influenciado la especiación de Capparaceae hacia ambientes mas secos. Además, la compleja dinámica del nicho climático en esta familia y, por lo tanto, la necesidad de realizar análisis más detallados para comprender mejor como las constricciones climáticas del NSDF afectaron la evolución de Capparaceae.

Genomic characterization of the non-O1/non-O139 Vibrio cholerae strain that caused a gastroenteritis outbreak in Santiago, Chile, 2018.

Vibrio cholerae is a human pathogen, which is transmitted by the consumption of contaminated food or water. V. cholerae strains belonging to the serogroups O1 and O139 can cause cholera outbreaks and epidemics, a severe life-threatening diarrheal disease. In contrast, serogroups other than O1 and O139, denominated as non-O1/non-O139, have been mainly associated with sporadic cases of moderate or mild diarrhea, bacteremia and wound infections. Here we investigated the virulence determinants and phylogenetic origin of a non-O1/non-O139 V. cholerae strain that caused a gastroenteritis outbreak in Santiago, Chile, 2018. We found that this outbreak strain lacks the classical virulence genes harboured by O1 and O139 strains, including the cholera toxin (CT) and the toxin-coregulated pilus (TCP). However, this strain carries genomic islands (GIs) encoding Type III and Type VI secretion systems (T3SS/T6SS) and antibiotic resistance genes. Moreover, we found these GIs are wide distributed among several lineages of non-O1/non-O139 strains. Our results suggest that the acquisition of these GIs may enhance the virulence of non-O1/non-O139 strains that lack the CT and TCP-encoding genes. Our results highlight the pathogenic potential of these V. cholerae strains.

Youth's school experience: Testing the role of symptoms of anxiety and co-occurring symptoms of depression.

Although symptoms of anxiety often coexist with symptoms of depression, little is known on how such coexistence affects youth's school experiences. OBJECTIVES: We tested how the two types of behaviors, when coexisting, were associated with youth's negative attitude toward teachers, school, and poor peer relations. METHOD: Data were collected from 203 ethnically and socioeconomically diverse youth (male: 24.6%; mean = 15.8 years, standard deviation = 2.4) with the 3rd edition of the Behavioral Assessment for Children: Self-Report of Personality. RESULTS: Scores for symptoms of depression alone explained negative attitude toward teachers (ß = .28; R2 = 17.88%), negative attitude toward school (ß = .27; R2 = 14.74%), and poor peer relations (ß = .42; R2 = 44.60%) as effectively as scores for both types of behaviors did. CONCLUSION: The coexistence of symptoms of anxiety and depression did not appear to impair youth's attitude toward teachers, school and peer relations more than symptoms of depression did alone.

Cumulative acquisition of pathogenicity islands has shaped virulence potential and contributed to the emergence of LEE-negative Shiga toxin-producing Escherichia coli strains.

Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens causing severe gastroenteritis, which may lead to hemolytic uremic syndrome. The Locus of Enterocyte Effacement (LEE), a Pathogenicity Island (PAI), is a major determinant of intestinal epithelium attachment of a group of STEC strains; however, the virulence repertoire of STEC strains lacking LEE, has not been fully characterized. The incidence of LEE-negative STEC strains has increased in several countries, highlighting the relevance of their study. In order to gain insights into the basis for the emergence of LEE-negative STEC strains, we performed a large-scale genomic analysis of 367 strains isolated worldwide from humans, animals, food and the environment. We identified uncharacterized genomic islands, including two PAIs and one Integrative Conjugative Element. Additionally, the Locus of Adhesion and Autoaggregation (LAA) was the most prevalent PAI among LEE-negative strains and we found that it contributes to colonization of the mice intestine. Our comprehensive and rigorous comparative genomic and phylogenetic analyses suggest that the accumulative acquisition of PAIs has played an important, but currently unappreciated role, in the evolution of virulence in these strains. This study provides new knowledge on the pathogenicity of LEE-negative STEC strains and identifies molecular markers for their epidemiological surveillance.

Episodio Hipotonía-Hiporreactividad posterior a la inmunización con vacuna combinada con pertussis de células enteras. Reporte de un caso / Hypotonic-Hyporesponsive Episode after immunization with whole-cell pertussis combination vaccine. Clinical Case Report

Resumen Introducción: El Episodio Hipotonía-Hiporreactividad (EHH) es un efecto adverso tras la vacuna ción, asociado principalmente a vacunas anti-pertussis de células enteras. Se caracteriza por un inicio súbito de flacidez muscular, reducida respuesta a estímulos y palidez cutánea o cianosis. Aunque el EHH es infrecuente, está considerado como un efecto adverso severo. Objetivo: Reportar un caso de EHH posterior a la administración de la vacuna combinada pentavalente con: difteria, tétanos, pertussis celular, hepatitis B y Haemophilus influenzae tipo b (DTwP-HB-Hib), que está incluida en el Programa Nacional de Inmunizaciones (PNI) de Chile, con la finalidad de difundir esta infrecuente complicación de evolución benigna, auto-limitada y de carácter no recurrente. Caso clínico: Lactante de 6 meses de edad, 3 h post-vacunación con la tercera dosis de vacuna DTwP-HB-Hib, presentó compromiso del estado de conciencia interpretado como convulsión atónica y que finalmente se consideró como EHH. El lactante evolucionó favorablemente después de 2 h y fue dado de alta tras 24 h de vigilancia clínica; se cambió el esquema de inmunización del lactante con vacunas anti-per tussis acelulares como medida preventiva. Conclusiones: El desconocimiento sobre el EHH puede desalentar la inmunización infantil. Por lo tanto, es importante que el personal médico informe a los padres de los pacientes sobre este evento benigno, autolimitado y no recurrente. En estos casos, se re comienda continuar con el programa de inmunización del lactante con formulaciones que contengan componentes anti-pertussis acelulares.

Abstract Introduction: Hypotonic-Hyporesponsive Episode (HHE) is an adverse event after vaccination, mainly associated with whole-cell pertussis vaccines. It is characterized by a sudden onset of muscle flaccidity, reduced response to stimuli and pallor or cyanosis. Although the HHE is infrequent, it is considered a severe adverse event. Objective: To report a case of HHE following the administration of the whole-cell pertussis combination vaccine (DTwP-HB-Hib), which is included in National Im munization Program (PNI) of Chile, and to contributing to the knowledge of this adverse event in the country. Case report: A 6-month-old infant, 3 hours post-vaccination with the third dose of DTwP-HB-Hib vaccine, presented a decreased level of consciousness that was interpreted as atonic seizure but finally considered as EHH. The infant progressed favorably after 2 hours of clinical observation and was discharged 24 hours later. Parents were suggested to continue the immunization schedule of the infant with acellular pertussis vaccines as a preventive measure. Conclusions: The lack of knowledge about the EHH may discourage childhood immunization. Therefore, it is important for the medical staff to inform parents of the patients about this benign, self-limited and non-recurrent adverse event. In these cases, it is recommended to continue the immunization schedule of the infant with acellular pertussis vaccines.

Pesquisa de Salmonella sp. em suínos abatidos sob inspeção municipal / Search for Salmonella sp. in swine slaughtered under municipal inspection

A pesquisa de micro-organismos nos alimentos é de vital importância, uma vez que, além de causadores de toxinfecções alimentares, servem de barreira às exportações e diminuem o tempo de vida de prateleira de produtos alimentícios. Garantir a inocuidade dos alimentos, assim como monitorar a contaminação dos produtos, é crucial para a saúde pública. Para garantir um alimento com qualidade e inocuidade é necessário uniformizar toda a cadeia produtiva desde a obtenção da matéria-prima até o produto final. No presente estudo, pesquisou-se a presença de Salmonella em amostras de linfonodos mesentéricos e conteúdo intestinal, bem como em quatro pontos da carcaça (papada, barriga, lombo e pernil), em 25 suínos abatidos em abatedouro- frigorífico sob inspeção municipal, provenientes de unidades produtivas que utilizam sobras alimentares como ração dos suínos. Verificou-se a presença de S. Saintpaul em conteúdo intestinal (4%) e linfonodos mesentéricos (12%), perfazendo um total de quatro (16%) suínos portadores; bem como a presenças de S. Saintpaul e S. Enteritidis em suabes de papada (8,0%). Em 18 isolados de Salmonella observou-se resistência a tetraciclina (66,6%), sulfa + trimetropim (38,8%), cloranfenicol (27,7%), nitrofurantoína (22,2%), cefalotina (22,2%), ampicilina (0,1%) e ácido nalidíxico (0,05%). A presença de suínos portadores de salmonela indica a necessidade de medidas preventivas no processo produtivo destes animais. Entretanto, a presença do agente na carcaça é indicativa de falhas na aplicação das boas práticas durante o abate.(AU)

Locus of Adhesion and Autoaggregation (LAA), a pathogenicity island present in emerging Shiga Toxin-producing Escherichia coli strains.

Shiga Toxin-producing Escherichia coli (STEC) are a group of foodborne pathogens associated with diarrhea, dysentery, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Shiga toxins are the major virulence factor of these pathogens, however adhesion and colonization to the human intestine is required for STEC pathogenesis. A subset of STEC strains carry the Locus of Enterocyte Effacement (LEE) pathogenicity island (PAI), which encodes genes that mediate the colonization of the human intestine. While LEE-positive STEC strains have traditionally been associated with human disease, the burden of disease caused by STEC strains that lacks LEE (LEE-negative) has increased recently in several countries; however, in the absence of LEE, the molecular pathogenic mechanisms by STEC strains are unknown. Here we report a 86-kb mosaic PAI composed of four modules that encode 80 genes, including novel and known virulence factors associated with adherence and autoaggregation. Therefore, we named this PAI as Locus of Adhesion and Autoaggregation (LAA). Phylogenomic analysis using whole-genome sequences of STEC strains available in the NCBI database indicates that LAA PAI is exclusively present in a subset of emerging LEE-negative STEC strains, including strains isolated from HC and HUS cases. We suggest that the acquisition of this PAI is a recent evolutionary event, which may contribute to the emergence of these STEC.

[Hypotonic-Hyporesponsive Episode after immunization with whole-cell pertussis combination vaccine. Clinical Case Report]. / Episodio Hipotonía-Hiporreactividad posterior a la inmunización con vacuna combinada con pertussis de células enteras. Reporte de un caso.

INTRODUCTION: Hypotonic-Hyporesponsive Episode (HHE) is an adverse event after vaccination, mainly associated with whole-cell pertussis vaccines. It is characterized by a sudden onset of muscle flaccidity, reduced response to stimuli and pallor or cyanosis. Although the HHE is infrequent, it is considered a severe adverse event. OBJECTIVE: To report a case of HHE following the administration of the whole-cell pertussis combination vaccine (DTwP-HB-Hib), which is included in National Im munization Program (PNI) of Chile, and to contributing to the knowledge of this adverse event in the country. CASE REPORT: A 6-month-old infant, 3 hours post-vaccination with the third dose of DTwP-HB-Hib vaccine, presented a decreased level of consciousness that was interpreted as atonic seizure but finally considered as EHH. The infant progressed favorably after 2 hours of clinical observation and was discharged 24 hours later. Parents were suggested to continue the immunization schedule of the infant with acellular pertussis vaccines as a preventive measure. CONCLUSIONS: The lack of knowledge about the EHH may discourage childhood immunization. Therefore, it is important for the medical staff to inform parents of the patients about this benign, self-limited and non-recurrent adverse event. In these cases, it is recommended to continue the immunization schedule of the infant with acellular pertussis vaccines.

Qualidade microbiológica de queijos produzidos com leite de cabra / Microbiological quality of cheeses produced with goat's milk

O objetivo do presente estudo foi identificar a qualidade microbiológica de queijos com diferentes processos de produção elaborados com leite de cabra. Oito queijos, produzidos em um laticínio do Rio Grande do Sul, foram analisados de acordo com a legislação vigente para pesquisa de Salmonella spp. e Listeria spp. e quantificação de coliformes totais e termotolerantes, aeróbios mesófilos totais e Staphylococcus coagulase positiva (SCP). Determinou-se ausência de coliformes termotolerantes, salmonelas e Listeria spp. em todos os produtos analisados. Verificou-se a presença de SCP (2x102 a 4,2x103 UFC.g-1) em seis amostras, coliformes totais (2x103 NMP.g-1) em apenas uma amostra e micro-organismos mesófilos aeróbios (8,8x102 a 1x106 UFC.g-1) nas oito amostras. Seis amostras foram consideradas impróprias para consumo pela elevada contagem de SCP, sendo este o agente mais frequentemente associado à contaminação de queijos.