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This study examined the diversity and persistence of Salmonella in the surface waters of agricultural regions of Brazil, Chile, and Mexico. Research groups (three in 2019-2020 and five in 2021-2022) conducted a long-term survey of surface water across 5-8 months annually (n = 30 monthly). On-site, each team filtered 10-L water samples with modified Moore Swabs to capture Salmonella, which were then isolated and identified using conventional microbiological techniques. Salmonella isolates were sequenced on Illumina platforms. Salmonella was present in 1,493/3,291 water samples (45.8%), with varying isolation rates across countries and years. Newport, Infantis, and Typhimurium were the most frequent among the 128 different serovars. Notably, 22 serovars were found in all three countries, representing almost half of the 1,911 different isolates collected. The resistome comprised 72 antimicrobial resistance (AMR) genes and six point mutations in three genes. At least one AMR determinant was observed in 33.8% (646/1,911) of the isolates, of which 47.4% (306/646) were potentially multidrug resistant. Phylogeny based on core genome multilocus sequence typing (cgMLST) showed that most isolates clustered according to sequence type and country of origin. Only 14 cgMLST multi-country clusters were detected among the 275 clusters. However, further analysis confirmed that close genetic relatedness occurred mostly among isolates from the same country, with three exceptions. Interestingly, isolates closely related phylogenetically were recovered over multiple years within the same country, indicating the persistence of certain Salmonella in those areas. In conclusion, surface waters in these regions are consistently contaminated with diverse Salmonella, including strains that persist over time.IMPORTANCESalmonella is a leading foodborne pathogen responsible for millions of illnesses, hospitalizations, and deaths annually. Although Salmonella-contaminated water has now been recognized as an important contamination source in the agrifood chain, there is a lack of knowledge on the global occurrence and diversity of Salmonella in surface water. Moreover, there has been insufficient research on Salmonella in surface waters from Latin American countries that are major producers and exporters of agricultural products. Incorporating genetic profiling of Salmonella isolates from underrepresented regions, such as Latin America, enhances our understanding of the pathogen's ecology, evolution, antimicrobial resistance, and pathogenicity. Moreover, leveraging genomic data derived from pathogens isolated from diverse geographical areas is critical for assessing the potential public health risk posed by the pathogen and expediting investigations of foodborne outbreaks. Ultimately, global efforts contribute significantly to reducing the incidence of foodborne infections.
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Salmonella , Microbiologia da Água , Brasil/epidemiologia , Salmonella/genética , Salmonella/classificação , Salmonella/isolamento & purificação , México/epidemiologia , Chile/epidemiologia , Variação Genética , Filogenia , Genoma Bacteriano , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Genômica , Epidemiologia MolecularRESUMO
Road traffic is the primary source of environmental noise pollution in cities. This problem is also spreading due to inadequate urban expansion planning. Hence, integrating road traffic noise analysis into urban planning is necessary for reducing city noise in an effective, adaptable, and sustainable way. This study aims to develop a methodology that applies to any city for the stratification of urban roads by their functionality through only their urban features. It is intended to be a tool to cluster similar streets and, consequently, traffic noise to enable urban and transportation planners to support the reduction of people's noise exposure. Three multivariate ordered logistic regression statistical models (Model 1, 2, and 3) are presented that significantly stratify urban roads into five, four, and three categories, respectively. The developed models exhibit a McFadden pseudo-R2 between 0.5 and 0.6 (equivalent to R2 >0.8). The choice between Model 1 or 2 depends on the scale of the city. Model 1 is recommended for developed cities with an extensive road network, while Model 2 is most suitable in intermediate and growing cities. On the other hand, Model 3 could be applied at any city scale but focused on local management of transit routes and for designing acoustic sensor installations, urban soundwalks, and identification of quiet areas. Urban features related to road width and length, presence of transport infrastructure, and public transport routes are associated with increased traffic noise in all three models. These models prove useful for future action plans aimed at reducing noise through strategic urban planning.
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Surface waters are considered ecological habitats where Salmonella enterica can persist and disseminate to fresh produce production systems. This study aimed to explore the genomic profiles of S. enterica serotypes Typhimurium, Newport, and Infantis from surface waters in Chile, Mexico, and Brazil collected between 2019 and 2022. We analyzed the whole genomes of 106 S. Typhimurium, 161 S. Newport, and 113 S. Infantis isolates. Our phylogenetic analysis exhibited distinct groupings of isolates by their respective countries except for a notable case involving a Chilean S. Newport isolate closely related to two Mexican isolates, showing 4 and 13 single nucleotide polymorphisms of difference, respectively. The patterns of the most frequently detected antimicrobial resistance genes varied across countries and serotypes. A strong correlation existed between integron carriage and genotypic multidrug resistance (MDR) across serotypes in Chile and Mexico (R > 0.90, P < 0.01), while integron(s) were not detected in any of the Brazilian isolates. By contrast, we did not identify any strong correlation between plasmid carriage and genotypic MDR across diverse countries and serotypes.IMPORTANCEUnveiling the genomic landscape of S. enterica in Latin American surface waters is pivotal for ensuring public health. This investigation sheds light on the intricate genomic diversity of S. enterica in surface waters across Chile, Mexico, and Brazil. Our research also addresses critical knowledge gaps, pioneering a comprehensive understanding of surface waters as a reservoir for multidrug-resistant S. enterica. By integrating our understanding of integron carriage as biomarkers into broader MDR control strategies, we can also work toward targeted interventions that mitigate the emergence and dissemination of MDR in S. enterica in surface waters. Given its potential implications for food safety, this study emphasizes the critical need for informed policies and collaborative initiatives to address the risks associated with S. enterica in surface waters.
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Farmacorresistência Bacteriana Múltipla , Filogenia , Salmonella enterica , Salmonella typhimurium , Sorogrupo , Salmonella enterica/genética , Salmonella enterica/isolamento & purificação , Salmonella enterica/classificação , Salmonella enterica/efeitos dos fármacos , Brasil , Farmacorresistência Bacteriana Múltipla/genética , México , Salmonella typhimurium/genética , Salmonella typhimurium/isolamento & purificação , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/classificação , Integrons/genética , Genoma Bacteriano , Chile , Genômica , Antibacterianos/farmacologia , América Latina , Microbiologia da Água , Polimorfismo de Nucleotídeo Único , Plasmídeos/genética , Testes de Sensibilidade MicrobianaRESUMO
In recent years, Salmonella enterica subsp. enterica serovar Mbandaka (S. Mbandaka) has been increasingly isolated from laying hens and shell eggs around the world. Moreover, this serovar has been identified as the causative agent of several salmonellosis outbreaks in humans. Surprisingly, little is known about the characteristics of this emerging serovar, and therefore, we investigated antimicrobial resistance, virulence, and prophage genes of six selected Brazilian strains of Salmonella Mbandaka using Whole Genome Sequencing (WGS). Multi-locus sequence typing revealed that the tested strains belong to Sequence Type 413 (ST413), which has been linked to recent multi-country salmonellosis outbreaks in Europe. A total of nine resistance genes were detected, and the most frequent ones were aac(6')-Iaa, sul1, qacE, blaOXA-129, tet(B), and aadA1. A point mutation in ParC at the 57th position (threonine â serine) associated with quinolone resistance was present in all investigated genomes. A 112,960 bp IncHI2A plasmid was mapped in 4/6 strains. This plasmid harboured tetracycline (tetACDR) and mercury (mer) resistance genes, genes contributing to conjugative transfer, and genes involved in plasmid maintenance. Most strains (four/six) carried Salmonella genomic island 1 (SGI1). All S. Mbandaka genomes carried seven pathogenicity islands (SPIs) involved in intracellular survival and virulence: SPIs 1-5, 9, and C63PI. The virulence genes csgC, fimY, tcfA, sscA, (two/six), and ssaS (one/six) were absent in some of the genomes; conversely, fimA, prgH, and mgtC were present in all of them. Five Salmonella bacteriophage sequences (with homology to Escherichia phage phiV10, Enterobacteria phage Fels-2, Enterobacteria phage HK542, Enterobacteria phage ST64T, Salmonella phage SW9) were identified, with protein counts between 31 and 54, genome lengths of 24.7 bp and 47.7 bp, and average GC content of 51.25%. In the phylogenetic analysis, the genomes of strains isolated from poultry in Brazil clustered into well-supported clades with a heterogeneous distribution, primarily associated with strains isolated from humans and food. The phylogenetic relationship of Brazilian S. Mbandaka suggests the presence of strains with high epidemiological significance and the potential to be linked to foodborne outbreaks. Overall, our results show that isolated strains of S. Mbandaka are multidrug-resistant and encode a rather conserved virulence machinery, which is an epidemiological hallmark of Salmonella strains that have successfully disseminated both regionally and globally.
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Introducción. La investigación sobre la pandemia de COVID-19, se ha estudiado en tiempo real, ha sido y sigue siendo reveladora. Objetivo. Analizar la morbilidad y la mortalidad por COVID-19, asociadas a factores de riesgo metabólicos en población no indígena e indígena de México. Materiales y métodos. Utilizamos la Base Nacional de Datos COVID-19, durante los años críticos 2020-2021- 2022. Se trabajó con 5.380.247 casos que representaron la población total de positivos al SARS-CoV-2. Se analizaron las discrepancias entre las prevalencias de población no indígena, población indígena, defunción y no defunción. Se definió población indígena, con la clasificación oficial de auto-identificación. Se aplicó el modelo de regresión logística para determinar el riesgo de morir para cada variable: enfermedades cardiovasculares, hipertensión, diabetes, obesidad, sexo, edad y condición indígena. El análisis de multicolinealidad se analizó a través de la prueba de asociación Phi para variables dicotómicas y a través del ajuste de Nagelkerke. Resultados. En los positivos totales 99,2% fue población no indígena y 0,8% indígenas, mientras su porcentaje de letalidad fue de 5,8% y 11,1% respectivamente. En ambos grupos, murieron más hombres (61,5%) que mujeres (38,5%) y las edades de mayor defunción fueron 60 a 79 años. La mortalidad por enfermedades cardiovasculares fue la de mayor incidencia, 26,6% en población general y 32,3% en indígena; por diabetes 22,1% y 27,9%; hipertensión 20,0% y 26,7%y la obesidad 11, 3% y 17,4% respectivamente. Los análisis de regresión logística se ajustaron por sexo, edad y condición indígena. El condicionante de mayor riesgo de muerte, fueron las comorbilidades metabólicas y el de menor riesgo, la condición indígena. Conclusiones. El impacto de la pandemia por COVID-19 fue más grave cuando hubo padecimientos metabólicos tanto en la población no indígena como en la indígena(AU)
Introduction. Research on the COVID-19 pandemic, studied in real time, has been and continues to be revealing. Objective. To analyze morbidity and mortality from COVID-19, associated with metabolic risk factors in non-indigenous and indigenous populations of Mexico. Materials and methods. We use the National COVID-19 Database, during the critical years 2020-2021-2022. We worked with 5,380,247 cases that represented the total population of SARS-CoV-2 positives. The discrepancies between the prevalence of non-indigenous population, indigenous population, death and non-death were analyzed. The indigenous population was defined, with the official self-identification classification. The logistic regression model was applied to determine the risk of dying for each variable: cardiovascular diseases, hypertension, diabetes, obesity, sex, age and indigenous status. The multicollinearity analysis was analyzed through the Phi association test for dichotomous variables and through the Nagelkerke adjustment. Results. Of the total positives, 99.2% were non-indigenous people and 0.8% were indigenous, while their fatality percentage was 5.8% and 11.1% respectively. In both groups, more men (61.5%) than women (38.5%) died and the ages of greatest death were 60 to 79 years. Mortality from cardiovascular diseases was the one with the highest incidence, 26.6% in the general population and 32.3% in the indigenous population; due to diabetes 22.1% and 27.9%; hypertension 20.0% and 26.7% and obesity 11.3% and 17.4% respectively. Logistic regression analyzes were adjusted for sex, age, and indigenous status. The condition with the highest risk of death was metabolic comorbidities and the lowest risk was indigenous status. Conclusions. The impact of the COVID-19 pandemic was more serious when there were metabolic disorders in both the non-indigenous and indigenous populations(AU)
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Humanos , Masculino , Adulto , Pessoa de Meia-Idade , Povos Indígenas , COVID-19/mortalidade , Doenças Metabólicas , Doenças Cardiovasculares , Diabetes Mellitus , Fatores Sociodemográficos , Hipertensão , ObesidadeRESUMO
Coffee is a crop of global relevance. Indirect somatic embryogenesis has allowed plants of different coffee genotypes to be massively regenerated. The culture medium composition can affect the calli characteristics that are generated and their ability to form somatic embryos. This research aimed to determine the influence of the type of callus, growth regulators, and phytagel concentration on the embryogenic capacity of the Colombia variety. Leaf explants were cultured on Murashige and Skoog medium with 2,4-dichlorophenoxyacetic acid (2,4-D) (0.5-1.0 mg L-1), benzylaminopurine (BAP, 1.0 mg L-1), and phytagel (2.3-5.0 g L-1). The explants generated two types of calli: friable (beige, soft, watery, easy disintegration, polyhedral parenchyma cells) and compact (white, hard, low water content, difficult disintegration, elongated parenchyma cells). About 68% of the total callus generated was compact; this type of callus produced a greater number of embryos (71.3) than the friable one (29.2). The number of differentiated embryos was significantly affected by the concentration of phytagel; higher concentrations (5.0 g L-1) resulted in larger quantities (73.7). The highest number of embryos (127.47) was obtained by combining 1.0 mg L-1 2,4-D, 1.0 mg L-1 BAP, 5.0 g L-1 phytagel, and compact callus.
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This paper presents the Synthetic Polyphonic Ambient Sound Source (SPASS) dataset, a publicly available synthetic polyphonic audio dataset. SPASS was designed to train deep neural networks effectively for polyphonic sound event detection (PSED) in urban soundscapes. SPASS contains synthetic recordings from five virtual environments: park, square, street, market, and waterfront. The data collection process consisted of the curation of different monophonic sound sources following a hierarchical class taxonomy, the configuration of the virtual environments with the RAVEN software library, the generation of all stimuli, and the processing of this data to create synthetic recordings of polyphonic sound events with their associated metadata. The dataset contains 5000 audio clips per environment, i.e., 25,000 stimuli of 10 s each, virtually recorded at a sampling rate of 44.1 kHz. This effort is part of the project ``Integrated System for the Analysis of Environmental Sound Sources: FuSA System'' in the city of Valdivia, Chile, which aims to develop a system for detecting and classifying environmental sound sources through deep Artificial Neural Network (ANN) models.
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Coffea arabica is one of the two most consumed coffee species in the world. Micropropagation through somatic embryogenesis has allowed the large-scale propagation of different coffee varieties. However, the regeneration of plants using this technique depends on the genotype. This study aimed to develop a protocol for the regeneration of C. arabica L. var. Colombia by somatic embryogenesis for its mass propagation. Foliar explants were cultured on Murashige and Skoog (MS) supplemented with different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP), and phytagel for inducing somatic embryogenesis. In total, 90% of the explants formed embryogenic calli with a culture medium containing 2 mg L-1 of 2,4-D, 0.2 mg L-1 BAP, and 2.3 g L-1 phytagel. The highest number of embryos per gram of callus (118.74) was obtained in a culture medium containing 0.5 mg L-1 2,4-D, 1.1 mg L-1 BAP, and 5.0 g L-1 phytagel. In total, 51% of the globular embryos reached the cotyledonary stage when they were cultured on the growth medium. This medium contained 0.25 mg L-1 BAP, 0.25 mg L-1 indoleacetic acid (IAA), and 5.0 g L-1 of phytagel. The mixture of vermiculite:perlite (3:1) allowed 21% of embryos to become plants.
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Since its emergence in the beginning of the 90's, multidrug-resistant (MDR) Salmonella enterica subsp. enterica serovar Kentucky has become a significant public health problem, especially in East Africa. This study aimed to investigate the antimicrobial resistance profile and the genotypic relatedness of Salmonella Kentucky isolated from animal sources in Ethiopia and Kenya (n=19). We also investigated population evolutionary dynamics through phylogenetic and pangenome analyses with additional publicly available Salmonella Kentucky ST198 genomes (n=229). All the 19 sequenced Salmonella Kentucky isolates were identified as ST198. Among these isolates, the predominant genotypic antimicrobial resistance profile observed in ten (59.7%) isolates included the aac(3)-Id, aadA7, strA-strB, blaTEM-1B, sul1, and tet(A) genes, which mediated resistance to gentamicin, streptomycin/spectinomycin, streptomycin, ampicillin, sulfamethoxazole and tetracycline, respectively; and gyrA and parC mutations associated to ciprofloxacin resistance. Four isolates harbored plasmid types Incl1 and/or Col8282; two of them carried both plasmids. Salmonella Pathogenicity islands (SPI-1 to SPI-5) were highly conserved in the 19 sequenced Salmonella Kentucky isolates. Moreover, at least one Pathogenicity Island (SPI 1-4, SPI 9 or C63PI) was identified among the 229 public Salmonella Kentucky genomes. The phylogenetic analysis revealed that almost all Salmonella Kentucky ST198 isolates (17/19) stemmed from a single strain that has accumulated ciprofloxacin resistance-mediating mutations. A total of 8,104 different genes were identified in a heterogenic and still open Salmonella Kentucky ST198 pangenome. Considering the virulence factors and antimicrobial resistance genes detected in Salmonella Kentucky, the implications of this pathogen to public health and the epidemiological drivers for its dissemination must be investigated.
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Salmonella enterica , Animais , Antibacterianos/farmacologia , Ciprofloxacina , Farmacorresistência Bacteriana Múltipla/genética , Genômica , Kentucky , Gado , Filogenia , Salmonella enterica/genética , Sorogrupo , EstreptomicinaRESUMO
The increasing number of studies reporting the presence of Salmonella in environmental water sources suggests that it is beyond incidental findings originated from sparse fecal contamination events. However, there is no consensus on the occurrence of Salmonella as its relative serovar representation across non-recycled water sources. We conducted a meta-analysis of proportions by fitting a random-effects model using the restricted maximum-likelihood estimator to obtain the weighted average proportion and between-study variance associated with the occurrence of Salmonella in water sources. Moreover, meta-regression and non-parametric supervised machine learning method were performed to predict the effect of moderators on the frequency of Salmonella in non-recycled water sources. Three sequential steps (identification of information sources, screening and eligibility) were performed to obtain a preliminary selection from identified abstracts and article titles. Questions related to the frequency of Salmonella in aquatic environments, as well as putative differences in the relative frequencies of the reported Salmonella serovars and the role of potential variable moderators (sample source, country, and sample volume) were formulated according to the population, intervention, comparison, and outcome method (PICO). The results were reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyzes statement (PRISMA). A total of 26 eligible papers reporting 148 different Salmonella serovars were retrieved. According to our model, the Salmonella frequency in non-recycled water sources was 0.19 [CI: 0.14; 0.25]. The source of water was identified as the most import variable affecting the frequency of Salmonella, estimated as 0.31 and 0.17% for surface and groundwater, respectively. There was a higher frequency of Salmonella in countries with lower human development index (HDI). Small volume samples of surface water resulted in lower detectable Salmonella frequencies both in high and low HDI regions. Relative frequencies of the 148 serovars were significantly affected only by HDI and volume. Considering that serovars representation can also be affected by water sample volume, efforts toward the standardization of water samplings for monitoring purposes should be considered. Further approaches such as metagenomics could provide more comprehensive insights about the microbial ecology of fresh water and its importance for the quality and safety of agricultural products.
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Multi-drug resistant (MDR) non-typhoidal Salmonella (NTS) is a public health concern globally. This study reports the phenotypic and genotypic antimicrobial resistance (AMR) profiles of NTS isolates from bovine lymph nodes (n = 48) and ground beef (n = 29). Furthermore, we compared genotypic AMR data of our isolates with those of publicly available NTS genomes from Mexico (n = 2400). The probability of finding MDR isolates was higher in ground beef than in lymph nodes:χ2 = 12.0, P = 0.0005. The most common resistant phenotypes involved tetracycline (40.3%), carbenicillin (26.0%), amoxicillin-clavulanic acid (20.8%), chloramphenicol (19.5%) and trimethoprim-sulfamethoxazole (16.9%), while more than 55% of the isolates showed decreased susceptibility to ciprofloxacin and 26% were MDR. Conversely, resistance to cephalosporins and carbapenems was infrequent (0-9%). MDR phenotypes were strongly associated with NTS serovar (χ2 = 24.5, P<0.0001), with Typhimurium accounting for 40% of MDR strains. Most of these (9/10), carried Salmonella genomic island 1, which harbors a class-1 integron with multiple AMR genes (aadA2, blaCARB-2, floR, sul1, tetG) that confer a penta-resistant phenotype. MDR phenotypes were also associated with mutations in the ramR gene (χ2 = 17.7, P<0.0001). Among public NTS isolates from Mexico, those from cattle and poultry had the highest proportion of MDR genotypes. Our results suggest that attaining significant improvements in AMR meat safety requires the identification and removal (or treatment) of product harboring MDR NTS, instead of screening for Salmonella spp. or for isolates showing resistance to individual antibiotics. In that sense, massive integration of whole genome sequencing (WGS) technologies in AMR surveillance provides the shortest path to accomplish these goals.
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Bovinos/microbiologia , Farmacorresistência Bacteriana , Farmacorresistência Bacteriana Múltipla , Genômica , Aves Domésticas/microbiologia , Salmonella/fisiologia , Animais , México , Salmonella/efeitos dos fármacosRESUMO
Multi-drug resistant (MDR) non-typhoidal Salmonella (NTS) is increasingly common worldwide. While food animals are thought to contribute to the growing antimicrobial resistance (AMR) problem, limited data is documenting this relationship, especially in low and middle-income countries (LMIC). Herein, we aimed to assess the role of non-clinical NTS of bovine origin as reservoirs of AMR genes of human clinical significance. We evaluated the phenotypic and genotypic AMR profiles in a set of 44 bovine-associated NTS. For comparative purposes, we also included genotypic AMR data of additional isolates from Mexico (n = 1,067) that are publicly available. The most frequent AMR phenotypes in our isolates involved tetracycline (40/44), trimethoprim-sulfamethoxazole (26/44), chloramphenicol (19/44), ampicillin (18/44), streptomycin (16/44), and carbenicillin (13/44), while nearly 70% of the strains were MDR. These phenotypes were correlated with a widespread distribution of AMR genes (i.e. tetA, aadA, dfrA12, dfrA17, sul1, sul2, bla-TEM-1, blaCARB-2) against multiple antibiotic classes, with some of them contributed by plasmids and/or class-1 integrons. We observed different AMR genotypes for betalactams and tetracycline resistance, providing evidence of convergent evolution and adaptive AMR. The probability of MDR genotype occurrence was higher in meat-associated isolates than in those from other sources (odds ratio 11.2, 95% confidence interval 4.5-27.9, P < 0.0001). The study shows that beef cattle are a significant source of MDR NTS in Mexico, highlighting the role of animal production on the emergence and spread of MDR Salmonella in LMIC.
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Doenças dos Bovinos/microbiologia , Doenças Transmissíveis Emergentes/veterinária , Farmacorresistência Bacteriana Múltipla , Salmonelose Animal/transmissão , Salmonella/efeitos dos fármacos , Salmonella/genética , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/microbiologia , Doenças Transmissíveis Emergentes/transmissão , Genômica , Gado/microbiologia , México/epidemiologia , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Plasmídeos/metabolismo , Salmonella/classificação , Salmonelose Animal/epidemiologia , Salmonelose Animal/microbiologiaRESUMO
Nontyphoidal Salmonella (NTS) is a common pathogen in food-producing animals and a public health concern worldwide. Various NTS serovars may be present in apparently healthy animals. This could result in carcass contamination during the slaughter process leading to human exposure. While most genomic research has focused on Salmonella pathogenesis, little is known on the factors associated with subclinical infections and environmental persistence. We report here the widespread distribution of typhoidal toxin genes (i. e. the cdtB islet, hlyE, taiA), among NTS strains from a beef slaughter operation (n = 39) and from epidemiologically unconnected ground beef (n = 20). These genes were present in 76% of the strains, regardless of serovar, isolation source or geographical location. Moreover, strains that predominated in the slaughterhouse carry plasmid-borne type IV secretion systems (T4SS), which have been linked to persistent infections in numerous pathogens. Population genomics supports clonal dissemination of NTS along the food production chain, highlighting its role as reservoir of genetic variability in the environment. Overall, the study provides a thorough characterization of serovar diversity and genomic features of beef-associated NTS in Mexico. Furthermore, it reveals how common genetic factors could partially explain the emergence and persistence of certain NTS serovars in the beef industry.
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Plasmídeos/genética , Salmonella/genética , Salmonella/fisiologia , Toxinas Biológicas/genética , Sequenciamento Completo do Genoma , Animais , Bovinos , Variação Genética , Genômica , Interações Hospedeiro-Patógeno , Filogenia , Salmonella/patogenicidade , Estresse Fisiológico , VirulênciaRESUMO
OBJECTIVE: To determine the serotype and antibiotic resistance profile of Salmonella spp. isolated from retail ground beef in Mexico City. MATERIALS AND METHODS: A total of 100 samples of ground beef were analyzed. The pathogen was isolated by conventional methods and confirmed by PCR (invA gene, 284 bp).The antibiotic resistance profile was determined by the Kirby-Bauer method while serotyping was performed according to the Kauffman-White scheme. RESULTS: We isolated a total of 19 strains of Lomita (6), Derby (4), Senftenberg (2), Javiana and Cannsttat (1) and undetermined (5) serotypes. The strains showed a high resistance rate to ampicillin (18/19), carbenicillin (16/19), tetracyclin (13/19), and trimethoprim-sulfamethoxazole (13/19). Multidrug resistance was observed in 14 isolates. CONCLUSIONS: Several Salmonella spp. serotypes of public health significance are circulating in ground beef sold in the major Mexican city. Some of these strains are multi-drug resistance.
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Resistência Microbiana a Medicamentos , Microbiologia de Alimentos , Carne Vermelha/microbiologia , Salmonella/efeitos dos fármacos , Animais , Bovinos , Humanos , Produtos da Carne/microbiologia , México , Salmonella/classificação , Salmonella/isolamento & purificação , Intoxicação Alimentar por Salmonella , Sorotipagem , Saúde da População UrbanaRESUMO
Resumen: Objetivo: Determinar el serotipo y perfil de resistencia a antibióticos de cepas de Salmonella spp. presentes en la carne de res que se expende en la capital mexicana. Material y métodos: Se analizaron 100 muestras de carne molida. Se aisló el patógeno por métodos convencionales y se confirmó por PCR (gen InvA, 284 pb). El perfil de resistencia a antibióticos se determinó por el método de Kirby-Bauer y la serotipificación por el esquema de Kauffman-White. Resultados: Se detectaron los serotipos Lomita (6), Derby (4), Senftenberg (2), Javiana y Cannsttat (1). Se observó alta resistencia a ampicilina (18/19), carbenicilina (16/19), tetraciclina (13/19) y trimetoprim-sulfametoxasol (13/19). Cinco cepas fueron no tipificables y 14 mostraron multirresistencia. Conclusiones: La carne de res que se vende en el principal centro de consumo del país está contaminada con serotipos de Salmonella spp. relevantes para la salud pública. Una importante proporción de éstos es resistente a múltiples antibióticos.
Abstract: Objective: To determine the serotype and antibiotic resistance profile of Salmonella spp. isolated from retail ground beef in Mexico City. Materials and methods: A total of 100 samples of ground beef were analyzed. The pathogen was isolated by conventional methods and confirmed by PCR (invA gene, 284 bp).The antibiotic resistance profile was determined by the Kirby-Bauer method while serotyping was performed according to the Kauffman-White scheme. Results: We isolated a total of 19 strains of Lomita (6), Derby (4), Senftenberg (2), Javiana and Cannsttat (1) and undetermined (5) serotypes. The strains showed a high resistance rate to ampicillin (18/19), carbenicillin (16/19), tetracyclin (13/19), and trimethoprim-sulfamethoxazole (13/19). Multidrug resistance was observed in 14 isolates. Conclusions: Several Salmonella spp. serotypes of public health significance are circulating in ground beef sold in the major Mexican city. Some of these strains are multi-drug resistance.
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Humanos , Animais , Salmonella/efeitos dos fármacos , Resistência Microbiana a Medicamentos , Carne Vermelha/microbiologia , Microbiologia de Alimentos , Salmonella/isolamento & purificação , Salmonella/classificação , Intoxicação Alimentar por Salmonella , Bovinos , Sorotipagem , Saúde da População Urbana , Produtos da Carne/microbiologia , MéxicoRESUMO
In many countries such as Chile, there is scarce official information for generating accurate noise maps. Therefore, specific simplification methods are becoming a real need for the acoustic community in developing countries. Thus, the main purpose of this work was to evaluate and apply simplified methods to generate a cost-effective traffic noise map of a small city of Chile. The experimental design involved the simplification of the cartographic information on buildings by clustering the households within a block, and the classification of the vehicular traffic flows into categories to generate an inexpensive noise map. The streets have been classified according to the official road classification of the country. Segregation of vehicles from light, heavy and motorbikes is made to account for traffic flow. In addition, a number of road traffic noise models were compared with noise measurements and consequently the road traffic model RLS-90 was chosen to generate the noise map of the city using the Computer Aided Noise Abatement (CadnaA) software. It was observed a direct dependence between noise levels and traffic flow versus each category of street used. The methodology developed in this study appears to be convenient in developing countries to obtain accurate approximations to develop inexpensive traffic noise maps.
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Objective. This paper presents extensions to the statistical validation method based on the procedure of Freese when a model shows constant bias (CB) in its predictions and illustrate the method with data from a new mechanistic model that predict weight gain in cattle. Materials and methods. The extensions were the hypothesis tests and maximum anticipated error for the alternative approach, and the confidence interval for a quantile of the distribution of errors. Results. The model evaluated showed CB, once the CB is removed and with a confidence level of 95%, the magnitude of the error does not exceed 0.575 kg. Therefore, the validated model can be used to predict the daily weight gain of cattle, although it will require an adjustment in its structure based on the presence of CB to increase the accuracy of its forecasts. Conclusions. The confidence interval for the 1-α quantile of the distribution of errors after correcting the constant bias, allows determining the top limit for the magnitude of the error of prediction and use it to evaluate the evolution of the model in the forecasting of the system. The confidence interval approach to validate a model is more informative than the hypothesis tests for the same purpose.
Objetivo. Presentar extensiones al método estadístico para validar modelos basado en el procedimiento de Freese cuando el modelo presenta sesgo constante (SC) en sus predicciones e ilustrar el método con datos provenientes de un modelo mecanístico inédito para la predicción de ganancia de peso de bovinos. Materiales y métodos. Las extensiones fueron la prueba de hipótesis y error máximo anticipado para el planteamiento alternativo y el intervalo de confianza para un cuantil de la distribución de los errores. Resultados. El modelo evaluado presentó SC, una vez eliminado y con un nivel de confianza del 95%, la magnitud del error no sobrepasa 0.575 kg. Por lo que el modelo validado puede usarse para predecir la ganancia de peso diaria de bovinos, aunque requerirá un ajuste en su estructura con base a la presencia de SC para incrementar la exactitud en sus pronósticos. Conclusiones. El intervalo de confianza para el cuantil 1-α de la distribución de los errores una vez que se corrige el sesgo constante, permite determinar una cota superior para la magnitud del error de predicción y usarla para evaluar la evolución del modelo en predicción del sistema. El enfoque de intervalos de confianza para validar un modelo es más informativo que las pruebas de hipótesis para el mismo propósito.
Assuntos
Estatística , Viés , Intervalos de ConfiançaRESUMO
Se afirma que el conocimiento humano es un modelo significante de la realidad que está constituido por la interacción de los modelos figurativos y los basados en signos. Se señalan algunas imprecisiones en la clasificación del conocimiento, como descriptivo, empírico y teórico. Se establecen algunas de las limitaciones del conocimiento empírico y se dan determinadas explicaciones sobre la necesidad de pasar al tipo de conocimiento activo transformador para investigar la esencia de los fenómenos que tienen lugar en la gestión del conocimiento.
It is assure that human knowledge is a significant model of reality made up by the interaction of the figurative models and those based on signs. In classification of knowledge as descriptive, empirical and theoretical knowledge, some imprecisions are pointed out. Some limitations of empirical knowledge are established giving determined explanations on the need of to change to transforming active knowledge to research the essence of phenomena present in the knowledge management.
Assuntos
Conhecimento , Gestão da InformaçãoRESUMO
Se propone el objeto de estudio de la Ciencia de la Información desde un análisis sistémico abstracto-analítico. Se argumenta que la Ciencia de la Información abstracto-analítica no estudia la información en toda su plenitud concreta, sino en un nivel determinado estructural de organización de la información. Se afirma que el objeto de estudio actual de la Ciencia de la Información, desde la perspectiva del conocimiento abstracto-analítico, lo constituye la interacción separada de forma abstracta, que corresponde con el nivel estructural-informacional de organización del sistema de información interactivo. Se considera, de esta manera, que el objeto de estudio de la Ciencia de la Información abstracto-analítica son las formas y regularidades de los vínculos sígnicos productivos, la interacción informacional del sujeto con el objeto. Se propone, de forma argumentada, un esquema perspectivo del desarrollo del sistema de ciencias de la información y su interrelación con las ciencias colindantes.
It is proposed the object of study of Science of the Information from a systemic abstract-analytic analysis. Also it is argued that the Science of the abstract-analytic Information doesn't study the information in all its concrete fullness, but in a certain structural level of organization of the information. It is affirmed that the current study of the Science of the Information, from the perspective of the abstract-analytic knowledge, constitutes the separated interaction from abstract form that corresponds with the structural-informacional level of organization of the interactive system of information. It is considered, in this way that the object of study of the Science of the abstract-analytic Information are the forms and regularities of the productive linguists links, the informational interaction of the subject with the object. Finally, it is proposed, -in an argued form-, a perspective scheme of the development of Sciences of Information system of and it's interrelation with adjacent sciences.
Assuntos
Ciência da Informação , Teoria da InformaçãoRESUMO
Se analizan algunos de los resultados obtenidos con la realización de una investigación sobre la gestión del conocimiento tácito, donde esta se trata desde la perspectiva de la Teoría de los modelos del mundo. Desde ese ángulo, se define el conocimiento como modelo significante y se propone un método grupal de diseminación del conocimiento y sus técnicas. Se señalan los pasos para crear el Equipo del conocimiento. Se explica como preparar y realizar la Reunión del conocimiento. Se indican algunas técnicas de dinámica de grupo para compartir el conocimiento.