Improving Our Understanding of Salmonella enterica Serovar Paratyphi B through the Engineering and Testing of a Live Attenuated Vaccine Strain.

Enteric fever is caused by three Salmonella enterica serovars: Typhi, Paratyphi A, and Paratyphi B sensu stricto Although vaccines against two of these serovars are licensed (Typhi) or in clinical development (Paratyphi A), as yet there are no candidates for S. Paratyphi B. To gain genomic insight into these serovars, we sequenced 38 enteric fever-associated strains from Chile and compared these with reference genomes. Each of the serovars was separated genomically based on the core genome. Genomic comparisons identified loci that were aberrant between serovars Paratyphi B sensu stricto and Paratyphi B Java, which is typically associated with gastroenteritis; however, the majority of these were annotated as hypothetical or phage related and thus were not ideal vaccine candidates. With the genomic information in hand, we engineered a live attenuated S. Paratyphi B sensu stricto vaccine strain, CVD 2005, which was capable of protecting mice from both homologous challenge and heterologous challenge with S. Paratyphi B Java. These findings extend our understanding of S. Paratyphi B and provide a viable vaccine option for inclusion in a trivalent live attenuated enteric fever vaccine formulation.IMPORTANCE We developed a live attenuated Salmonella enterica serovar Paratyphi B vaccine that conferred protection in mice against challenge with S Paratyphi B sensu stricto and S Paratyphi B Java, which are the causes of enteric fever and gastroenteritis, respectively. Currently, the incidence of invasive S. Paratyphi B sensu stricto infections is low; however, the development of new conjugate vaccines against other enteric fever serovars could lead to the emergence of S. Paratyphi B to fill the niche left by these other pathogens. As such, an effective S. Paratyphi B vaccine would be a useful tool in the armamentarium against Salmonella infections. Comparative genomics confirmed the serovar-specific groupings of these isolates and revealed that there are a limited number of genetic differences between the sensu stricto and Java strains, which are mostly hypothetical and phage-encoded proteins. The observed level of genomic similarity likely explains why we observe some cross-protection.

New product, old problem(s): multistate outbreak of Salmonella Paratyphi B variant L(+) tartrate(+) infections linked to raw sprouted nut butters, October 2015.

A cluster of Salmonella Paratyphi B variant L(+) tartrate(+) infections with indistinguishable pulsed-field gel electrophoresis patterns was detected in October 2015. Interviews initially identified nut butters, kale, kombucha, chia seeds and nutrition bars as common exposures. Epidemiologic, environmental and traceback investigations were conducted. Thirteen ill people infected with the outbreak strain were identified in 10 states with illness onset during 18 July-22 November 2015. Eight of 10 (80%) ill people reported eating Brand A raw sprouted nut butters. Brand A conducted a voluntary recall. Raw sprouted nut butters are a novel outbreak vehicle, though contaminated raw nuts, nut butters and sprouted seeds have all caused outbreaks previously. Firms producing raw sprouted products, including nut butters, should consider a kill step to reduce the risk of contamination. People at greater risk for foodborne illness may wish to consider avoiding raw products containing raw sprouted ingredients.

Salmonella paratyphy B and Salmonella lithcfield outbreaks associated with petturtle exporure in Spain

Introduction: Salmonellosis is an important public health problem. Turtles are increasingly involved in the role of transmitters of this infection to humans. Methods: Salmonella cases are reported to the local Surveillance Agency where interviews are carriedout to address possible exposures. Molecular epidemiology techniques were used to identify species. Results: In this article we report two examples of this type of infection in two places, 300 km apart in Spain. In Barcelona a turtle transmitted the disease to a small baby via her mother, and in Castellón 5 related cases of Salmonella infections were detected, and all were transmitted by imported turtles. Molecular epidemiology techniques confirmed the turtle-person transmissions and showed strong relationships between cases in Castellón and Barcelona. Discussion: These examples represent the tip of the iceberg of what is happening with pet reptiles as regards transmission of this infection. We believe that it is important to assess the impact of this type of infection in each country, in order to subsequently promote prevention strategies such as: regulations for pet shops, and educating/informing families who buy reptiles as pets (AU)

Introducción: La salmonelosis es un problema con un impacto importante en salud pública. Cada día es más importante el papel de las tortugas como transmisoras de esta enfermedad. Métodos: Los casos de salmonelosis son notiflcados a las Agencias de Vigilancia locales que realizan las encuestas pertinentes para valorar fuentes de exposición. Técnicas de epidemiologia molecular son utilizadas para identiflcar las especies. Resultados: En este artículo exponemos ejemplos de este tipo de transmisión en dos puntos de España que distan 300 km. En Barcelona una tortuga transmitió la enfermedad a un bebé a través de su madrey en Castellón se registraron cinco casos de infecciones por Salmonella, todos ellos provocados por el contacto con tortugas. La epidemiologia molecular permitió conflrmar la transmisión tortuga persona y así como una fuerte relación entre los casos de Barcelona y Castellón. Discusión: Estos ejemplos representan la punta del Iceberg en cuanto al papel de los reptiles en la transmisión de Salmonella. Creemos que evaluar el impacto de esta transmisión en los países es básico para poder aplicar y promover medidas preventivas. Normativas específlcas en los puntos de venta de reptiles así como información y educación de las familias que pretenden comprar un animal de este tipo podrían ser muy útiles para disminuir el impacto de esta transmisión (AU)

Characterization of pathogenic and resistant genome repertoire reveals two clonal lines in Salmonella enterica subsp. enterica serovar Paratyphi B (+)-tartrate positive.

A total of 36 contemporary human, animal, and environmental (+)-tartrate-fermenting (dT+) Salmonella enterica serovar Paratyphi B isolates, formerly called Salmonella serovar Java, and five related monophasic S. enterica serovar 4,5,12:b:- isolates from Belgium, Germany, the Netherlands, and the United Kingdom were investigated for clonality and antimicrobial resistance profiles, as well as their virulence and resistance gene repertoire. Two major clonal lines, which could be phenotypically differentiated by the expression of the O:5 antigen, were identified. All O:5 antigen negative strains were multidrug resistant and originated (with two exceptions) from Belgian, Dutch, or German poultry. Strains exhibiting the O:5 antigen encoded by the oafA gene revealed a more heterogeneous group including multidrug-resistant and susceptible strains. Compared to O:5 antigen negative isolates, Salmonella Paratyphi B dT+ O:5 positive strains possessed additional virulence determinants. The Salmonella genomic island 1 was only found in O:5 positive strains. Five monophasic Salmonella 4,5,12:b:- lacking the phase-2 flagellar antigen were assigned to Salmonella Paratyphi B dT+ isolates of the O:5 positive group. The conclusion of the analysis is that Salmonella Paratyphi B dT+ O:5 negative and O:5 positive isolates evolved from a different lineage. Salmonella Paratyphi B dT+ O:5 positive strains possess additional fimbrial and virulence genes that probably enable this clone to interact with a broader range of hosts and the environment. Salmonella Paratyphi B dT+ O:5 negative continuously persists in poultry across Western Europe, especially Belgium, the Netherlands, and Germany.

Sporadic infections of Salmonella Paratyphi B, var. Java associated with fish tanks.

OBJECTIVE: Identify a source of contamination to explain the increase in the number of cases of S. Paratyphi B var. Java infection. METHOD: A descriptive study was conducted to gather more information about cases and potential risk factors for infection. Between January 2000 and June 2003, we identified and interviewed by questionnaire 53 people with S. Paratyphi B infection. Due to the suspected link with fish tanks, an environmental investigation was conducted for each case at patients' homes as well as at pet stores and wholesalers. Various samples were taken from fish tanks. The fish were purchased at different pet shops. The pulsed field gel electrophoresis method was used to compare the human and aquarium strains. RESULTS: Of those infected, 60% had bought or had contact with an aquarium or tropical fishes before becoming ill. More than 50% of the samples taken from fish tanks in homes, pet shops, and wholesaler operations contained a number of serotypes of Salmonella in addition to Salmonella Paratyphi B var. Java. There were similarities between the PFGE patterns of human strains and aquarium samples. DISCUSSION: Contact with fish tanks could be a risk factor for developing a Salmonella infection and the public may be unaware of this risk. It was recommended that information be produced and distributed to pet shops and their customers to inform them of safety precautions in order to reduce the risk of contamination from bacterial pathogens that may be present in aquarium water.

Reversible encephalopathy secondary to paratyphoid infection and concomitant acute Hepatitis A.

Reversible encephalopathy has been described in association with typhoid fever as well as nontyphoidal salmonella infections. A diagnostic dilemma as to the cause of encephalopathy may arise when there is coexistent acute viral hepatitis and suspicion of fulminant liver failure. The authors report a patient who presented with acute icteric hepatitis A infection and a concomitant febrile illness due to Salmonella paratyphi associated with progressive encephalopathy and coma. The young man developed high-grade fever and coma. Concomitant infection with S. paratyphi was diagnosed and the patient's encephalopathy resolved rapidly with antibiotic therapy. This is the first report of a putative association of S. paratyphi infection and reversible encephalopathy. Salmonella and hepatitis A virus infection are both transmitted via the fecal-oral route, and awareness of this association is important in the management of such patients.

Emergence of multidrug-resistant Salmonella Paratyphi B dT+, Canada.

We document an increase in the number of multidrug-resistant Salmonella enterica serovar Paratyphi B dT+ identified in Canada. Most of these strains harbor Salmonella genomic island 1 (SGI1). Further studies are needed to determine factors contributing to the observed emergence of this multidrug-resistant strain.

Molecular properties of Salmonella enterica serotype paratyphi B distinguish between its systemic and its enteric pathovars.

Salmonella enterica serotype O1,4,5,12:Hb:1,2, designated according to the current Kauffmann-White scheme as S. enterica serotype Paratyphi B, is a very diverse serotype with respect to its clinical and microbiological properties. PCR and blot techniques, which identify the presence, polymorphism, and expression of various effector protein genes, help to distinguish between strains with systemic and enteric outcomes of disease. All serotype Paratyphi B strains from systemic infections have been found to be somewhat genetically related with respect to the pattern of their virulence genes sopB, sopD, sopE1, avrA, and sptP as well as other molecular properties (multilocus enzyme electrophoresis type, pulsed-field gel electrophoresis [PFGE] type, ribotype, and IS200 type). They have been classified as members of the systemic pathovar (SPV). All these SPV strains possess a new sopE1-carrying bacteriophage (designated PhiSopE309) with high SopE1 protein expression but lack the commonly occurring avrA determinant. They exhibit normal SopB protein expression but lack SopD protein production. In contrast, strains from enteric infections classified as belonging to the enteric pathovar possess various combinations of the respective virulence genes, PFGE pattern, and ribotypes. We propose that the PCR technique for testing for the presence of the virulence genes sopE1 and avrA be used as a diagnostic tool for identifying both pathovars of S. enterica serotype Paratyphi B. This will be of great public health importance, since strains of serotype Paratyphi B have recently reemerged worldwide.

The pathogenicity of strains of Salmonella paratyphi B and Salmonella java.

AIMS: To relate the diseases caused by strains of Salmonella paratyphi B and S. java to pathogenic mechanisms expressed by these bacteria for the purpose of organism discrimination. METHODS AND RESULTS: Epidemiological data relating to cases of disease caused by strains of S. paratyphi B and S. java, isolated over a 10-year period, were analysed with respect to patients' symptoms, particularly those involving enteric fever. Strains of S. paratyphi B and S. java were also examined for a range of known pathogenic mechanisms. Infection with S. paratyphi B involved pyrexia in 12.5% of patients compared with 2.2% of patients infected with S. java. These organisms could not be differentiated based on the pathogenic properties examined. CONCLUSIONS: Strains of S. paratyphi B appear not to be a major cause of enteric fever but primarily a cause of gastroenteritis, in common with S. java. Both organisms express similar pathogenic mechanisms, and strains of S. java are probably d-tartrate utilizing variants of S. paratyphi B. SIGNIFICANCE AND IMPACT OF THE STUDY: Strains of S. paratyphi B are very closely related organisms, primarily causing gastroenteritis. From this study it would appear that strains of S. paratyphi B are not a major cause of enteric fever.

Fiebre paratifoídea B en dos áreas de Santiago: un análisis de su significación epidemiológica / Paratyphoid B fever in Santiago, Chile: epidemiological significance

Salmonella isolates from 3920 patients with typho8id fever form 2 years in Santiago wetre analyzed to determine the frequency of association with S paratyphi B infection. This was demonstrated in 18.8% of subjects in both areas, a figure significantly higher than the 8-10% previously reported. the association S paratyphi B was higher for females, especially for the younger age agrupo. These findings suggest an infectious agentgender-age interaction which may explain the discrepancy with previously report rates of infection. Their possible relation to the chronic salmonella carrier state and association with biliary tract lithiasis and cancer is discussed

Fiebre paratifoidea B en niños del área norte de Santiago: un análisis de su significación epidemiológica / Paratyphoid B fever in children of the north area in Santiago: analysis of its epidemiological significance

Las fiebres tifoidea y paratifoidea son consideradas clínica y epidemiológicamente casi una misma entidad. Sin embargo, para estudios clínico-epidemiológicos, en particular los dirigidos a estudios inmunogenéticos sobre la relación huésped-agente, estas salmonellas deben ser consideradas como diferentes. Este estudio fue hecho para estudiar posibles cambios en el comportamiento de la Salmonella paratyphi B (SPTB) luego de haber sido introducida la cepa viva de la vacuna oral Ty21a en el Area Norte de Santiago. Se revisaron los resultados de hemo y mielocultivos del Laboratorio de Microbiología del Hospital Roberto del Río hechos durante 1983 y el período 1986-89. De 1.204 fiebres tíficas bacteriológicamente comprobadas, el 22,4% correspondieron a SPTB, lo cual fue una frecuencia inesperadamente más alta que las estimaciones anteriores (p < 0,02). En mujeres tíficas, la SPTB fue más frecuente que en varones (p < 0,02). En 697 niños seleccionados por ser residentes del Area Norte, la SPTB fue dos veces más la causa de la enfermedad que en varones de la misma edad (p < 0,009). Se comenta estos resultados teniendo en cuenta que la portación crónica de salmonelas tíficas afecta principalmente a mujeres (5,5: 1). Los resultados no permiten establecer el papel de vacuna oral en los fenómenos descritos

Effect of human leukocyte interferon on invasiveness of Salmonella species in HEp-2 cell cultures.

The effect of human leukocyte interferon on the invasiveness of Salmonella and Shigella species in HEp-2 cell cultures was examined. The intracellular and extracellular bacteria were identified by a combination of Nomarski differential interference contrast microscopy and UV incident light microscopy applied on the same microscope. Pretreatment of HEp-2 cells with human leukocyte interferon reduced the number of Salmonella typhimurium and Salmonella paratyphi-B bacteria per cell and the proportion of cells containing bacteria in a dose-dependent manner. Maximum inhibitory effect was observed with ca. 100 U of interferon per ml. The inhibitory effect was neutralized with anti-human interferon globulin. Murine fibroblast interferon did not influence the invasiveness of Salmonella species. Invasiveness of Shigella flexneri was not influenced by treatment of cells with human interferon.

[Effect of conjugative R plasmids on the virulence of antibiotic-sensitive Salmonella strains and their streptomycin-resistant mutants]. / Vliianie kon"iugativnykh R-plazmid na virulentnost' chuvstvitel'nykh k antibiotikam shatmmov sal'monell i ikh streptomitsinorezistentnykh mutantov.

The pathogenicity level of antibiotic sensitive and streptomycin resistant strains of S. typhimurium, S. paratyphi B and S. kottbus changed under the effect of identical R plasmids more frequently in contrary directions. The conjugative plasmids of antibiotic resistance widened the ranges of the virulence changes in the Salmonella serovars for albino mice. It was found that 7 out of 8 plasmids studied significantly decreased and increased the virulence of the antibiotic sensitive Salmonella strains. As a rule, R plasmids of various origin decreased the virulence of all the tested streptomycin chromosome resistant causative agents of salmonellosis.

[Relationship between the presence of K- and O-antigens and the behavior of salmonellae in a culture of macrophages]. / Povedenie sal'monell v kul'ture makrofagov v zavisimosti ot nalichiia K- i O-antigenov

It was shown on experimental models (mice and in kerato-conjunctival reaction) in comparative study of spontaneous stable salmonella mutants that disturbances in the process of synthesis of K- or O-antigens led to the weakening or the loss of the bacterial virulence. In the study of the behavior of the salmonella mutants it was revealed in the culture of phagocytizing macrophages that a reduction of the cytotoxic action of bacteria was connected with the changes of the somatic O-antigen, whereas the capacity of salmonella to reproduction inside the macrophages correlated with the presence of surface K-antigen.