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Maize (Zea mays L.) is an important cereal crop worldwide. Contaminated maize kernels pose a significant mycotoxin exposure risk for humans in Latin America. Fumonisins, the most prevalent mycotoxin in maize, typically occur during pre-harvest conditions leading to significant economic losses. Various factors, including weather conditions, may influence this contamination. This study aimed to determine the association between fumonisin B1 (FB1) contamination, prevalence of Fusarium verticillioides, weather conditions and kernel quality in the two primary maize production areas in Costa Rica (Brunca and Chorotega). All maize samples (100%) showed FB1 contamination, with higher concentrations in samples from Brunca region, consistent with the presence of F. verticilliodes. Weather conditions appeared to play an important role in this contamination, since Brunca region had the highest mean temperature and relative humidity after maize silking (R1) and the total monthly rainfall in this region was significantly higher during the last two months of maize cultivation (grain-filling and physiological maturity stages R3 to R6). Interestingly, this study found a negative correlation between grain damage and kernel contamination with FB1 and F. verticillioides. The concentration of mineral nutrients in kernels from both regions was largely similar. Most nutrients in kernels exhibited a negative correlation with FB1, particularly nitrogen. Zinc and phosphorus were the only nutrients in kernels showing a positive correlation with FB1 in samples from the Brunca region. The results highlight elevated levels of FB1 contamination in maize and contribute to a better understanding of pre-harvest factors influencing FB1 contamination in tropical conditions.

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In this work, we report a successful protocol to obtain in vitro peach palm (Bactris gasipaes Kunth) "Diamantes 10" plants through somatic embryogenesis from transverse thin cell layer (TCL) explants, dissected from three sections (basal, medial, and apical) of lateral offshoots of adult plants cultured on different concentrations of 4-amino-3,5,6-trichloropicolonic acid (picloram). After swelling and development of primary callus in all treatments, without any strong effect of explant origin or picloram concentration, it was possible to observe the formation of embryogenic structures and the exact point from where they developed. Browning was also observed and correlated to the induction treatments, although it was not an impairment for the production of embryogenic structures. Subsequent maturation and conversion of somatic embryos into plantlets allowed their acclimatization 17 months after culture initiation (ACI), which was quicker than previous reports with juvenile tissues (from embryos or seed-germinated plantlets). To the best of our knowledge, this is the first report on peach palm regeneration through somatic embryogenesis from TCL explants from adult plants and could constitute, after fine-tuning the acclimatization stage, a tool for mass clonal propagation of elite genotypes of this open-pollinated crop, as well as for the establishment of conservation strategies of in situ gene bank plant accessions endangered due to aging and other threats.

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In the last 10 years, Salmonella Heidelberg has been extensively isolated from poultry in several countries. In this context, molecular characterization is essential to understand whether the strains have entered the farms from a single or several sources. Thus, the aim of this study was to determine the genetic relationship and antimicrobial susceptibility of S. Heidelberg strains isolated between 2011 and 2012 from broiler farms belonging to three integrated poultry companies located in Argentina. The genetic relatedness of the S. Heidelberg isolates was determined by pulsed-field gel electrophoresis (PFGE), and resistance to 21 antimicrobials was determined by the disc diffusion method. The isolates were assigned to four PFGE patterns. Most of the strains showed 100% similarity and belonged to the same integrated poultry company. This PFGE pattern was also prevalent in S. Heidelberg strains isolated from humans in several provinces of Argentina, which suggests an epidemiological association between human and poultry strains. All the isolates were classified as multidrug-resistant (MDR), and no clear relationship was observed between PFGE and resistance patterns. S. Heidelberg strains may circulate among farms from the same integrated company due to common sources of contamination. To guarantee the safety of the poultry product for the consumers, holistic approaches including surveillance of Salmonella throughout the production chain together with control measures are crucial.

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In order to control and eradicate epidemic cholera, we need to understand how epidemics begin, how they spread, and how they decline and eventually end. This requires extensive sampling of epidemic disease over time, alongside the background of endemic disease that may exist concurrently with the epidemic. The unique circumstances surrounding the Argentinian cholera epidemic of 1992-1998 presented an opportunity to do this. Here, we use 490 Argentinian V. cholerae genome sequences to characterise the variation within, and between, epidemic and endemic V. cholerae. We show that, during the 1992-1998 cholera epidemic, the invariant epidemic clone co-existed alongside highly diverse members of the Vibrio cholerae species in Argentina, and we contrast the clonality of epidemic V. cholerae with the background diversity of local endemic bacteria. Our findings refine and add nuance to our genomic definitions of epidemic and endemic cholera, and are of direct relevance to controlling current and future cholera epidemics.

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Shigella spp. are a leading cause of human diarrheal disease worldwide, with Shigella flexneri being the most frequently isolated species in developing countries. This serogroup is presently classified into 19 serotypes worldwide. We report here a multicenter validation of a multiplex-PCR-based strategy previously developed by Q. Sun, R. Lan, Y. Wang, A. Zhao, et al. (J Clin Microbiol 49:3766-3770, 2011) for molecular serotyping of S. flexneri This study was performed by seven international laboratories, with a panel of 71 strains (researchers were blind to their identity) as well as 279 strains collected from each laboratory's own local culture collections. This collaborative work found a high extent of agreement among laboratories, calculated through interrater reliability (IRR) measures for the PCR test that proved its robustness. Agreement with the traditional method (serology) was also observed in all laboratories for 14 serotypes studied, while specific genetic events could be responsible for the discrepancies among methodologies in the other 5 serotypes, as determined by PCR product sequencing in most of the cases. This work provided an empirical framework that allowed the use of this molecular method to serotype S. flexneri and showed several advantages over the traditional method of serological typing. These advantages included overcoming the problem of availability of suitable antisera in testing laboratories as well as facilitating the analysis of multiple samples at the same time. The method is also less time-consuming for completion and easier to implement in routine laboratories. We recommend that this PCR be adopted, as it is a reliable diagnostic and characterization methodology that can be used globally for laboratory-based shigella surveillance.

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This study examined the southern or Patagonian (41°-55° S) stock of Argentine hake Merluccius hubbsi, the more abundant of the two stocks on the Argentinean continental shelf. Pre-recruits (age 0+ year individuals) of this stock settle and grow in the San Jorge Gulf (45°-47° S, 65° 30' W), a complex habitat with large spatial variability in environmental features. Relative condition factor, hepatosomatic index, lipid content and fatty-acid composition of muscle and liver, and diet information were combined with physical and biological data to evaluate: how nutritional status of age 0+ year hake varies spatially within the nursery ground; whether changes in condition are related to environmental factors and feeding; whether the indices are interchangeable metrics of condition. Both morphometric and biochemical indices showed dissimilar spatial trends; enhanced liver-based condition coincided with low salinity nutrient rich waters, higher chlorophyll-a values and abundances of Euphausia spp., the preferred prey at most stations, suggesting a bottom-up effect on age 0+ year hake condition. Diminished condition at stations where Thermisto gaudichaudii was the main prey could derive from lower prey quality in terms of energy density and essential fatty acids content. Coastal waters of the gulf would be essential habitats for M. hubbsi pre-recruits. Future monitoring of condition with liver-based indices is encouraged in the gulf, where interannual increasing trends of satellite-derived chlorophyll-a values have been observed, which could have implications for recruitment of the species.

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The aim of this study was to describe an outbreak of Shigella sonnei that occurred in the city of Lujan, Buenos Aires, Argentina, in July 2012. Five individuals were affected after eating a hand-made Viennese-style pastry at a family gathering. All of them presented with fever, joint pain, chills and non-bloody diarrhea containing mucus. Stool cultures were performed in all cases and the samples taken from the pastry ingredients were analyzed microbiologically. S.sonnei was isolated and identified in all the patients involved as well as in the almond cream filling. The isolates were analyzed for determining the antimicrobial susceptibility and genetic profiles by pulsed field gel electrophoresis (PFGE). The results showed the genetic relationship among the isolates, confirming that the cases occurred due to the patients' exposure to the same source of infection, i.e., the almond cream. Being the almond cream an industrially-manufactured ingredient, an initial contamination could have been unlikely; however contamination might have occurred as a result of manipulation in the bakery.

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El objetivo del estudio fue describir un brote por Shigella sonnei ocurrido en julio de 2012 en Luján, Buenos Aires, Argentina. Estuvieron afectadas 5 personas que asistieron a una reunión familiar, donde consumieron una rosca vienesa de elaboración artesanal adquirida en un comercio. Todos presentaron fiebre, dolores articulares, escalofríos y diarrea no sanguinolenta con mucus. Se realizaron coprocultivos en los afectados y análisis microbiológicos de los ingredientes. Se aisló y caracterizó S.sonnei de todos los pacientes y de la crema de almendras empleada en la preparación de la rosca vienesa. A los aislamientos se les determinó el perfil de sensibilidad a los antimicrobianos y el genético por electroforesis en campo pulsado. Los resultados demostraron la relación genética de los aislamientos, y esto confirmó la ocurrencia de los casos por exposición a una misma fuente de infección, la crema de almendras. Al ser un ingrediente industrial, de improbable contaminación inicial, la crema de almendras podría haber sufrido una contaminación durante la manipulación en la panadería

The aim of this study was to describe an outbreak of Shigella sonnei that occurred in the city of Lujan, Buenos Aires, Argentina, in July 2012. Five individuals were affected after eating a handmade Viennese-style pastry at a family gathering. All of them presented with fever, joint pain, chills and non-bloody diarrhea containing mucus. Stool cultures were performed in all cases and the samples taken from the pastry ingredients were analyzed microbiologically. S.sonnei was isolated and identified in all the patients involved as well as in the almond cream filling. The isolates were analyzed for determining the antimicrobial susceptibility and genetic profiles by pulsed field gel electrophoresis (PFGE). The results showed the genetic relationship among the isolates, confirming that the cases occurred due to the patients' exposure to the same source of infection, i.e., the almond cream. Being the almond cream an industrially-manufactured ingredient, an initial contamination could have been unlikely; however contamination might have occurred as a result of manipulation in the bakery

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Shigella flexneri is divided into 13 serotypes based on the combination of antigenic determinants present in the O-antigen. A new O-antigen modification with phosphoethanolamine has been identified. The presence of this antigenic determinant (called E1037) is recognized by monoclonal antibody MASF IV-1. Given the increasing incidence of these new variants and the difficulty in supplying the monoclonal antibody to our country, we produced a polyclonal antiserum (AA479) through immunization with a S. flexneri Xv strain. The antiserum specificity was assessed by slide agglutination against isolates from clinical cases and a culture collection representing all Shigella serotypes. The results obtained demonstrated a 100% correlation between AA479 absorbed antiserum and monoclonal antibody MASF IV-1. The availability of AA479 antiserum in every public hospital in Argentina will allow us to identify atypical S. flexneri isolates in order to strengthen Shigella surveillance in our country and to compare with global epidemiological data.

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Shigella flexneri is divided into 13 serotypes based on the combination of antigenic determinants present in the O-antigen. A new O-antigen modification with phosphoethanolamine has been identified. The presence of this antigenic determinant (called E1037) is recognized by monoclonal antibody MASF IV-1. Given the increasing incidence of these new variants and the difficulty in supplying the monoclonal antibody to our country, we produced a polyclonal antiserum (AA479) through immunization with a S. flexneri Xv strain. The antiserum specificity was assessed by slide agglutination against isolates from clinical cases and a culture collection representing all Shigella serotypes. The results obtained demonstrated a 100% correlation between AA479 absorbed antiserum and monoclonal antibody MASF IV-1. The availability of AA479 antiserum in every public hospital in Argentina will allow us to identify atypical S. flexneri isolates in order to strengthen Shigella surveillance in our country and to compare with global epidemiological dat

Shigella flexneri se divide en al menos 13 serotipos sobre la base de la combinación de determinantes antigénicos presentes en el antígeno O. Se identificó una nueva modificación del antígeno O con fosfoetanolamina. La presencia de este determinante antigénico (denominado E1037) es reconocida por el anticuerpo monoclonal MASF IV-1. Teniendo en cuenta la incidencia creciente de estas nuevas variantes y la dificultad en la provisión del anticuerpo monoclonal para nuestro país, se elaboró un antisuero de tipo policlonal (AA479) mediante la inmunización con un cultivo de S. flexneri Xv. La especificidad del antisuero se evaluó por aglutinación en lámina con aislamientos clínicos y cultivos de colección, con lo que quedaron representados todos los serotipos de Shigella. Los resultados obtenidos demostraron una correlación del 100% entre el antisuero AA479 absorbido y el anticuerpo monoclonal MASF IV-1. La disponibilidad del antisuero AA479 en todos los hospitales públicos de Argentina permitirá identificar los aislamientos atípicos de S. flexneri; de esta forma se podrá fortalecer la vigilancia de Shigella en nuestro país y comparar con los datos epidemiológicos a nivel global

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Shigella flexneri is divided into 13 serotypes based on the combination of antigenic determinants present in the O-antigen. A new O-antigen modification with phosphoethanolamine has been identified. The presence of this antigenic determinant (called E1037) is recognized by monoclonal antibody MASF IV-1. Given the increasing incidence of these new variants and the difficulty in supplying the monoclonal antibody to our country, we produced a polyclonal antiserum (AA479) through immunization with a S. flexneri Xv strain. The antiserum specificity was assessed by slide agglutination against isolates from clinical cases and a culture collection representing all Shigella serotypes. The results obtained demonstrated a 100

correlation between AA479 absorbed antiserum and monoclonal antibody MASF IV-1. The availability of AA479 antiserum in every public hospital in Argentina will allow us to identify atypical S. flexneri isolates in order to strengthen Shigella surveillance in our country and to compare with global epidemiological data.

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BACKGROUND: To implement effective control measures, timely outbreak detection is essential. Shigella is the most common cause of bacterial diarrhea in Argentina. Highly resistant clones of Shigella have emerged, and outbreaks have been recognized in closed settings and in whole communities. We hereby report our experience with an evolving, integrated, laboratory-based, near real-time surveillance system operating in six contiguous provinces of Argentina during April 2009 to March 2012. METHODOLOGY: To detect localized shigellosis outbreaks timely, we used the prospective space-time permutation scan statistic algorithm of SaTScan, embedded in WHONET software. Twenty three laboratories sent updated Shigella data on a weekly basis to the National Reference Laboratory. Cluster detection analysis was performed at several taxonomic levels: for all Shigella spp., for serotypes within species and for antimicrobial resistance phenotypes within species. Shigella isolates associated with statistically significant signals (clusters in time/space with recurrence interval ≥365 days) were subtyped by pulsed field gel electrophoresis (PFGE) using PulseNet protocols. PRINCIPAL FINDINGS: In three years of active surveillance, our system detected 32 statistically significant events, 26 of them identified before hospital staff was aware of any unexpected increase in the number of Shigella isolates. Twenty-six signals were investigated by PFGE, which confirmed a close relationship among the isolates for 22 events (84.6%). Seven events were investigated epidemiologically, which revealed links among the patients. Seventeen events were found at the resistance profile level. The system detected events of public health importance: infrequent resistance profiles, long-lasting and/or re-emergent clusters and events important for their duration or size, which were reported to local public health authorities. CONCLUSIONS/SIGNIFICANCE: The WHONET-SaTScan system may serve as a model for surveillance and can be applied to other pathogens, implemented by other networks, and scaled up to national and international levels for early detection and control of outbreaks.

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The prevalence of Campylobacter spp. was investigated in 327 patients suffering from diarrhea and in 36 animals (dogs, cats and chickens) owned by the patients that presented infection by Campylobacter in Santa Rosa, La Pampa, Argentina. Campylobacter spp. was isolated in 50/327 patients and in 12/36 animals, being Campylobacter jejuni the most common species. Resistance to ciprofloxacin (65 %) and tetracycline (32 %) was found among 35 isolates of human origin studied. Seven genetic subtypes were observed among 13 C. jejuni isolates by pulsed field gel electrophoresis. Two subtypes grouped isolates belonging to patients and their respective dogs whereas another subtype grouped one isolate of human origin and two isolates from the patient's chickens. The results of this investigation highlight the need to strengthen surveillance of Campylobacter spp. not only in poultry, which is recognized as the main reservoir, but also in pets, which were shown to be asymptomatic carriers of the pathogen.

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Species of Oithona (Copepoda, Cyclopoida) are highly abundant, ecologically important, and widely distributed throughout the world oceans. Although there are valid and detailed descriptions of the species, routine species identifications remain challenging due to their small size, subtle morphological diagnostic traits, and the description of geographic forms or varieties. This study examined three species of Oithona (O. similis, O. atlantica and O. nana) occurring in the Argentine sector of the South Atlantic Ocean based on DNA sequence variation of a 575 base-pair region of 28S rDNA, with comparative analysis of these species from other North and South Atlantic regions. DNA sequence variation clearly resolved and discriminated the species, and revealed low levels of intraspecific variation among North and South Atlantic populations of each species. The 28S rDNA region was thus shown to provide an accurate and reliable means of identifying the species throughout the sampled domain. Analysis of 28S rDNA variation for additional species collected throughout the global ocean will be useful to accurately characterize biogeographical distributions of the species and to examine phylogenetic relationships among them.

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La embriogénesis somática (ES) es una vía de desarrollo in vitro que presenta una serie de ventajas sobre otras técnicas utilizadas para la regeneración de palmas. Esta técnica tiene gran potencial para superar las limitaciones observadas al tratar de propagar clonalmente estas plantas utilizando yemas basales. A pesar de la conocida recalcitrancia que presentan las palmas al cultivo in vitro, si se utilizan los reguladores de crecimiento apropiados, el tipo y el estado de desarrollo del explante adecuados, así como genotipos con buena respuesta, es muy probable que se obtengan buenos resultados. Esto ha sido demostrado parcialmente en Phoenix dactylifera (palma dátil), Elaeis guineensis (palma aceitera), Bactris gasipaes (pejibaye) y Cocos nucifera (coco). También se ha logrado generar protocolos eficientes en otras palmas menos estudiadas, como Geonoma gamiova (una palma ornamental), Euterpe edulis (palmito dulce) y Areca catechu (palma de betel). La inducción de ES se ha conseguido principalmente con el uso de auxinas. De ellas, la que se ha utilizado con más frecuencia es el ácido 2,4-diclorofenoxiacético (2,4-D), aunque en algunos casos (como en pejibaye y palma aceitera) se ha usado picloram y dicamba, también con buenos resultados. Los explantes más utilizados han sido inflorescencias, ápices y segmentos basales de hojas, todos con un estado de desarrollo incipiente. También se ha visto que el tamaño del explante y el medio de cultivo juegan un papel importante en la respuesta. En este trabajo se presenta una recopilación de los trabajos más importantes sobre ES en esta familia de plantas y del efecto de varios factores sobre su establecimiento y desarrollo.

Somatic embryogenesis (SE) is an in vitro developmental pathway that exhibits a number of advantages over other techniques for regeneration of palms. This technique has great potential to overcome the limitations observed when trying to propagate these plants clonally using basal buds. Despite the known recalcitrance of palms for in vitro culture, good results can be obtained by using the appropriate growth regulators, explant type and developmental stage, as well as responsive genotypes. This has been partially observed in Phoenix dactylifera (date palm), Elaeis guineensis (African oil palm), Bactris gasipaes (peach palm) and Cocos nucifera (coconut). Efficient protocols have been also generated in less-studied palms, such as Geonoma gamiova (an ornamental palm), Euterpe edulis (Assai palm) and Areca catechu (areca palm). Induction of SE has been achieved mainly through the use of auxins. Of these, 2,4-dichlorophenoxyacetic acid (2,4-D) has been used most frequently, although in some cases (such as in peach palm and African oil palm) picloram and dicamba have been employed also with good results. The most commonly used explants are young inflorescences, apical buds and leaf-basal segments. Explant size and culture medium also play an important role in obtaining good results. This review presents a compilation of the most important publications on SE in this plant family and the effect of various factors on induction and development of this pathway.

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BACKGROUND: Modern medical education is focused on students, and it is necessary to assess its level of satisfaction. A questionnaire was validated and we then conducted a study about the educational satisfaction level of medical residents of the Hospital General of Mexico. METHODS: An observational, descriptive, cross-sectional and prospective study was conducted. A questionnaire of 21 items was validated and then applied to a representative sample of medical residents. Each item was evaluated with a scale from 0 to 10 and then gathered in groups: 0-5 = poor, 6-7 = average, 8 = good, 9 = very good, and 10 = excellent. Descriptive and inferential statistics were carried out using SPSS v.17.0. RESULTS: The questionnaire had internal validity with Cronbach's alpha >0.91 by item. Included in the study were 355 medical residents representing 37 different specialties. The performance perception of the ìheadî professors showed a wide heterogeneity: excellent (23.7%), very good (20.6%), good (16.9%), average (23.1%), poor (15.8%). Fourth-year residents and upward valued the educational performance higher (p = 0.001) as well as medical/surgical residents (p = 0.02). Intermediate-level residents valued the professor higher (p = 0.001), similar to students who were married or living with a partner (p <0.001). Upon contrasting the evaluation of the teacher's performance with the overall course performance, a linear, direct and significant correlation was obtained with Spearman's correlation coefficient = 0.78 and regression coefficient (p <0.001). CONCLUSIONS: We found a wide range of heterogeneity of results. Performance of the professors was the basic component to judge the quality of the residents' courses.

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OBJECTIVE: To determine the associations of metabolic syndrome (MS) with residential area and lifestyle in men from Oaxaca, Mexico. MATERIAL AND METHODS: A cross-sectional study was conducted in 1998 in 325 apparently healthy men 35 to 65 years of age in four residential areas: rural, urban poor, urban middle, and urban rich. MS was defined according to International Diabetes Federation (IDF) guidelines. Information on physical activity and diet was collected by questionnaire. Based on two 24-hour recalls, a diet quality index (DQI) using eight WHO recommendations to prevent chronic diseases was constructed. RESULTS: The MS rate was 41.2%; twice as high in urban (45.4%) than rural (27.6%) subjects. A significantly higher risk of MS was associated with low DQI in urban poor (OR 2.5; CI: 1.0-6.3) and rich (OR 3.2; CI: 1.5-8.6), compared to rural subjects. Physical activity was an independent protective factor. CONCLUSIONS: MS is highly prevalent in apparently healthy men in urban areas, illustrating the role of diet and lifestyle transition.

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OBJECTIVE: To determine the associations of metabolic syndrome (MS) with residential area and lifestyle in men from Oaxaca, Mexico. MATERIAL AND METHODS: A cross-sectional study was conducted in 1998 in 325 apparently healthy men 35 to 65 years of age in four residential areas: rural, urban poor, urban middle, and urban rich. MS was defined according to International Diabetes Federation (IDF) guidelines. Information on physical activity and diet was collected by questionnaire. Based on two 24-hour recalls, a diet quality index (DQI) using eight WHO recommendations to prevent chronic diseases was constructed. RESULTS: The MS rate was 41.2 percent; twice as high in urban (45.4 percent) than rural (27.6 percent) subjects. A significantly higher risk of MS was associated with low DQI in urban poor (OR 2.5; CI: 1.0-6.3) and rich (OR 3.2; CI: 1.5-8.6), compared to rural subjects. Physical activity was an independent protective factor. CONCLUSIONS: MS is highly prevalent in apparently healthy men in urban areas, illustrating the role of diet and lifestyle transition.

OBJETIVO: Determinar las asociaciones entre el síndrome metabólico (SM) con el área residencial y el estilo de vida en hombres de Oaxaca, México. MATERIAL Y MÉTODOS: Estudio transversal en 325 adultos en cuatro áreas residenciales: rural y urbano (pobre, medio y rico), realizado en 1998. Se utilizó la definición de IDF para SM y documentó la actividad física y dieta. Con base en dos recordatorios de 24-horas, se construyó un índice de calidad nutricional (ICN) utilizando ocho recomendaciones de la OMS para la prevención de enfermedades crónicas. RESULTADOS:. La prevalencia general del SM fue de 41.2 por ciento, y doblemente mayor en urbanos ricos (45.4 por ciento) que en rurales (27.6 por ciento). Un riesgo significativamente más elevado de SM se asoció con un ICN bajo en urbanos pobres y en sujetos ricos (OR 3.2; IC: 1.5-8.6). La actividad física fue un factor protector independiente. CONCLUSIONES: El SM es altamente prevalente en hombres aparentemente sanos en áreas urbanas, lo cual refleja el papel de la transición nutricional y del estilo de vida.

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