Genomic characterisation of the population structure and antibiotic resistance of Salmonella enterica serovar Infantis in Chile, 2009-2022.

Background: Multidrug-resistant (MDR) Salmonella Infantis has disseminated worldwide, mainly linked to the consumption of poultry products. Evidence shows dissemination of this pathogen in Chile; however, studies are primarily limited to phenotypic data or involve few isolates. As human cases of Salmonella Infantis infections have substantially increased in recent years, this study aimed to characterise the genomic epidemiology and antimicrobial-resistance profiles of isolates obtained from different sources, aiming to inform effective surveillance and control measures. Methods: We sequenced 396 Salmonella Infantis genomes and analysed them with all publicly available genomes of this pathogen from Chile (440 genomes in total), representing isolates from environmental, food, animal, and human sources obtained from 2009 to 2022. Based on bioinformatic and phenotypic methods, we assessed the population structure, dissemination among different niches, and antimicrobial resistance (AMR) profiles of Salmonella Infantis in the country. Findings: The genomic and phylogenetic analyses showed that Salmonella Infantis from Chile comprised several clusters of highly related isolates dominated by sequence type 32. The HC20_343 cluster grouped an important proportion of all isolates. This was the only cluster associated with pESI-like megaplasmids, and up to 12 acquired AMR genes/mutations predicted to result in an MDR phenotype. Accordingly, antimicrobial-susceptibility testing revealed a strong concordance between the AMR genetic determinants and their matching phenotypic expression, indicating that a significant proportion of HC20_343 isolates produce extended-spectrum ß-lactamases and have intermediate fluoroquinolone resistance. HC20_343 Salmonella Infantis were spread among environmental, animal, food, and human niches, showing a close relationship between isolates from different years and sources, and a low intra-source genomic diversity. Interpretation: Our findings show a widespread dissemination of MDR Salmonella Infantis from the HC20_343 cluster in Chile. The high proportion of isolates with resistance to first-line antibiotics and the evidence of active transmission between the environment, animals, food, and humans highlight the urgency of improved surveillance and control measures in the country. As HC20_343 isolates predominate in the Americas, our results suggest a high prevalence of ESBL-producing Salmonella Infantis with intermediate fluoroquinolone resistance in the continent. Funding: Partially supported by the Food and Drug Administration (FDA) of the U.S. Department of Health and Human Services as part of an award, FDU001818, with 30% percent funded by FDA/HHS; and by Agencia de Investigación y Desarrollo de Chile (ANID) through FONDECYT de Postdoctorado Folio 3230796 and Folio 3210317, FONDECYT Regular Folio 1231082, and ANID-Millennium Science Initiative Program-ICN2021_044.

Long-Term Interactions of Salmonella Enteritidis With a Lytic Phage for 21 Days in High Nutrients Media.

Salmonella spp. is a relevant foodborne pathogen with worldwide distribution. To mitigate Salmonella infections, bacteriophages represent an alternative to antimicrobials and chemicals in food animals and food in general. Bacteriophages (phages) are viruses that infect bacteria, which interact constantly with their host. Importantly, the study of these interactions is crucial for the use of phages as a mitigation strategy. In this study, experimental coevolution of Salmonella Enteritidis (S. Enteritidis) and a lytic phage was conducted in tryptic soy broth for 21 days. Transfer to fresh media was conducted daily and every 24 hours, 2 mL of the sample was collected to quantify Salmonella OD600 and phage titter. Additionally, time-shift experiments were conducted on 20 colonies selected on days 1, 12, and 21 to evaluate the evolution of resistance to past (day 1), present (day 12), and future (day 21) phage populations. The behavior of the dynamics was modeled and simulated with mathematical mass-action models. Bacteria and phage from days 1 and 21 were sequenced to determine the emergence of mutations. We found that S. Enteritidis grew for 21 days in the presence and absence of the phage and developed resistance to the phage from day 1. Also, the phage was also able to survive in the media for 21 days, however, the phage titer decreased in approx. 3 logs PFU/mL. The stability of the lytic phage population was consistent with the leaky resistance model. The time-shift experiments showed resistance to phages from day 1 of at least 85% to the past, present, and future phages. Sequencing of S. Enteritidis showed mutations in genes involved in lipopolysaccharide biosynthesis genes rfbP and rfbN at day 21. The phage showed mutations in the tail phage proteins responsible for recognizing the cell surface receptors. These results suggest that interactions between bacteria and phage in a rich resource media generate a rapid resistance to the infective phage but a fraction of the population remains susceptible. Interactions between Salmonella and lytic phages are an important component for the rational use of phages to control this important foodborne pathogen.

Environmental and anthropogenic factors associated with the likelihood of detecting Salmonella in agricultural watersheds.

Surface water is one of the primary sources of irrigation water for produce production; therefore, its contamination by foodborne pathogens, such as Salmonella, may substantially impact public health. In this study, we determined the presence of Salmonella in surface water and characterized the relationship between Salmonella detection and environmental and anthropogenic factors. From April 2019 to February 2020, 120 samples from 30 sites were collected monthly in four watersheds located in two different central Chile agricultural regions (N = 1080). Water samples from rivers, canals, streams, and ponds linked to each watershed were obtained. Surface water (10 L) was filtrated in situ, and samples were analyzed for the presence of Salmonella. Salmonella was detected every month in all watersheds, with a mean detection percentage of 28% (0%-90%) across sampling sites, regardless of the season. Overall, similar detection percentages were observed for both regions: 29.1% for Metropolitan and 27.0% for Maule. Salmonella was most often detected in summer (39.8% of all summer samples tested positive) and least often in winter (14.4% of winter samples). Random forest analysis showed that season, water source, and month, followed by latitude and river, were the most influential factors associated with Salmonella detection. The influences of water pH and temperature (categorized as environmental factors) and factors associated with human activity (categorized as anthropogenic factors) registered at the sampling site were weakly or not associated with Salmonella detection. In conclusion, Salmonella was detected in surface water potentially used for irrigation, and its presence was linked to season and water source factors. Interventions are necessary to prevent contamination of produce, such as water treatment before irrigation.

Manejo de las lesiones anexiales en el embarazo y actualización del abordaje laparoscópico / Management of adnexal masses in pregnancy and an update of the laparoscopic approach

Resumen El manejo del tumor anexial en embarazadas sigue siendo un desafío. El objetivo del siguiente trabajo es realizar una revisión bibliográfica, en la que se abordarán las diferentes alternativas en cuanto a diagnóstico y manejo del tumor anexial en embarazadas, así como también indicaciones de abordaje quirúrgico y recomendaciones para una cirugía segura. Los tumores anexiales en embarazadas son poco frecuentes, y la mayoría son benignos y tipo funcionales. La ecografía ha sido fundamental para lograr diferenciar su carácter benigno o maligno. El manejo puede ser expectante o quirúrgico. El manejo quirúrgico se reserva para ciertas características de las lesiones anexiales. En cuanto a la vía operatoria, la literatura apoya la laparoscopia mostrando que existen múltiples beneficios al compararla con la laparotomía. Para el abordaje quirúrgico existen opciones en cuanto a la técnica, siendo estas anexectomía o quistectomía. Resulta fundamental tener consideraciones especiales en la técnica debido a los cambios fisiológicos de las embarazadas, como por ejemplo la altura uterina y el tamaño del tumor anexial. A modo de conclusión, el manejo de los tumores anexiales en el embarazo sigue siendo controversial y se extrapola principalmente basándose en la literatura de pacientes no gestantes u otros procedimientos quirúrgicos en embarazadas.

Abstract Nowadays the management of the adnexal tumors in pregnant women is still a challenge. The purpose of this article is to perform a bibliographic review and present the differential diagnosis, management, and surgical approaches for the women in this condition. Adnexal tumors in pregnant women are rare, most of them are benign corresponding to functional cysts. In order to differentiate benign from malignant tumors, Ultrasonography has been one of the most important imaging advances. The management can be either expectant or surgical. Surgical management is referred for tumors with certain specific characteristics. In relation to surgical management, the literature supports laparoscopy, showing greater benefits in comparison to laparotomy. There are different options for this kind of approach. Its mandatory to have special considerations in the technique due to the physiological changes in pregnant women, some examples are the uterine and the tumor size. The management of the adnexal tumors in pregnancy is still controversial, its based on studies of non-pregnant patients or other kinds of surgeries in pregnant women.

Frequency of pediatric dentomaxilar anomalies in Orthodontics Barros Luco Trudeau healthcare complex, Chile / Frecuencia de anomalías dentomaxilares pediátricas en ortodoncia perteneciente al complejo asistencial Barros Luco Trudeau, Chile

ABSTRACT Introduction: Dentomaxilar anomalies (DMA) are the third most common oral pathology in Chile. Objective: To determine the frequent of dentomaxilar anomalies observed in patients treated in the Department of Orthodontic of Dental Specialties Service (DSS) belonging to the Barros Luco Trudeau Healthcare Complex, Santiago, Chile. The population belongs to pediatric patients between 5 and 15 years, who have DMA, treated in the southern metropolitan health service. Method: The sample of 250 patients with DMA was chosen from April to September of the year 2019, therefore, the data was extracted from the clinical records of the patients. The classification of the anomalies was carried out using the Bonn's biogenetic method, modified by the University of Chile. Result: It was observed that the most frequent intermaxillary DMA of the sample is in the transverse direction and corresponds to the unilateral crossbite, on the other hand, the most frequent intramaxillary DMA is the alteration of dentoalveolar per large tooth. All intermaxillary DMA agreed to be more frequent at the age of 9 years. Conclusion: It was possible to define the frequency of the DMA in patients treated in the DSS, this being in the transverse direction, corresponding to unilateral crossbite. With the present study it is intended to make a contribution for future studies that use similar methodologies.

RESUMEN Introducción: Las anomalías dentomaxilares (ADM) son la tercera patología bucal más frecuente en Chile. Objetivo: Determinar la distribución de frecuencia de anomalías dentomaxilares observadas en los pacientes atendidos por el Departamento de Ortodoncia dentro del Servicio de Especialidades Odontológicas (SEO) perteneciente al Complejo Asistencial Barros Luco Trudeau, Santiago de Chile. La población pertenece a pacientes pediátricos entre 5 y 15 años de edad que presentan ADM, atendidos dentro del servicio de salud metropolitano sur. Método: La muestra de 250 pacientes con ADM fué recolectada a partir del mes de abril a septiembre del año 2019, por lo tanto, es una muestra por conveniencia, los datos fueron extraídos de las fichas clínicas de los pacientes. La clasificación de las anomalías estudiadas fue realizada mediante la clasificación biogenética de Bonn modificada por la cátedra de la Universidad de Chile. Resultado: Se observó que la ADM intermaxilar más frecuente de la muestra es en el sentido transversal y corresponde en el espacio lateral a la mordida cruzada unilateral, por otra parte, la ADM intramaxilar más frecuente es la alteración de tamaño dentoalveolar por diente grande. Todas las ADM intermaxilares coincidieron en ser más frecuentes a la edad de 9 años. Conclusión: Se logró determinar la distribución de las frecuencias de ADM en pacientes atendidos dentro del SEO, siendo esta en el sentido transversal, correspondiente a mordida cruzada unilateral. Con el presente estudio se pretende hacer una contribución para futuros estudios que utilicen metodologías similares.

Isolation of Ciprofloxacin and Ceftazidime-Resistant Enterobacterales From Vegetables and River Water Is Strongly Associated With the Season and the Sample Type.

The dissemination of antibiotic-resistant bacteria (ARB) from water used for crop irrigation to vegetables is poorly studied. During a year, five farmer markets in a city in Central Chile were visited, and 478 vegetable samples (parsleys, corianders, celeries, lettuces, chards, and beets) were collected. Simultaneously, 32 water samples were collected from two rivers which are used to irrigate the vegetables produced in the area. Resistant Enterobacterales were isolated and identified. Colistin resistance gene mcr-1 and extended spectrum ß-lactamases (ESBL) were molecularly detected. The association of environmental factors was evaluated, with the outcomes being the presence of Enterobacterales resistant to four antibiotic families and the presence of multidrug resistance (MDR) phenotypes. Parsley, coriander, and celery showed the highest prevalence of resistant Enterobacterales (41.9% for ciprofloxacin and 18.5% for ceftazidime). A total of 155 isolates were obtained, including Escherichia coli (n=109), Citrobacter sp. (n=20), Enterobacter cloacae complex (n=8), Klebsiella pneumoniae (n=8), and Klebsiella aerogenes (n=1). Resistance to ampicillin (63.2%) and ciprofloxacin (74.2%) was most frequently found; 34.5% of the isolates showed resistance to third-generation cephalosporins, and the MDR phenotype represented 51.6% of the isolates. In two E. coli isolates (1.29%), the gene mcr-1 was found and ESBL genes were found in 23/62 isolates (37%), with bla CTX-M being the most frequently found in 20 isolates (32%). Resistant Enterobacterales isolated during the rainy season were less likely to be MDR as compared to the dry season. Understanding environmental associations represent the first step toward an improved understanding of the public health impact of ARB in vegetables and water.

The NarE protein of Neisseria gonorrhoeae catalyzes ADP-ribosylation of several ADP-ribose acceptors despite an N-terminal deletion.

The ADP-ribosylating enzymes are encoded in many pathogenic bacteria in order to affect essential functions of the host. In this study, we show that Neisseria gonorrhoeae possess a locus that corresponds to the ADP-ribosyltransferase NarE, a previously characterized enzyme in N. meningitidis The 291 bp coding sequence of gonococcal narE shares 100% identity with part of the coding sequence of the meningococcal narE gene due to a frameshift previously described, thus leading to a 49-amino-acid deletion at the N-terminus of gonococcal NarE protein. However, we found a promoter region and a GTG start codon, which allowed expression of the protein as demonstrated by RT-PCR and western blot analyses. Using a gonococcal NarE-6xHis fusion protein, we demonstrated that the gonococcal enzyme underwent auto-ADP-ribosylation but to a lower extent than meningococcal NarE. We also observed that gonoccocal NarE exhibited ADP-ribosyltransferase activity using agmatine and cell-free host proteins as ADP-ribose acceptors, but its activity was inhibited by human ß-defensins. Taken together, our results showed that NarE of Neisseria gonorrhoeae is a functional enzyme that possesses key features of bacterial ADP-ribosylating enzymes.

The enzymes LSD1 and Set1A cooperate with the viral protein HBx to establish an active hepatitis B viral chromatin state.

With about 350 million people chronically infected around the world hepatitis B is a major health problem. Template for progeny HBV synthesis is the viral genome, organized as a minichromosome (cccDNA) inside the hepatocyte nucleus. How viral cccDNA gene expression is regulated by its chromatin structure; more importantly, how the modulation of this structure impacts on viral gene expression remains elusive. Here, we found that the enzyme SetDB1 contributes to setting up a repressed cccDNA chromatin state. This repressive state is activated by the histone lysine demethylase-1 (LSD1). Consistently, inhibiting or reducing LSD1 levels led to repression of viral gene expression. This correlates with the transcriptionally repressive mark H3K9 methylation and reduction on the activating marks H3 acetylation and H3K4 methylation on viral promoters. Investigating the importance of viral proteins we found that LSD1 recruitment to viral promoters was dependent on the viral transactivator protein HBx. Moreover, the histone methyltransferase Set1A and HBx are simultaneously bound to the core promoter, and Set1A expression correlates with cccDNA H3K4 methylation. Our results shed light on the mechanisms of HBV regulation mediated by the cccDNA chromatin structure, offering new therapeutic targets to develop drugs for the treatment of chronically infected HBV patients.

Methylation of histone H3 lysine 9 occurs during translation.

Histone post-translational modifications are key contributors to chromatin structure and function, and participate in the maintenance of genome stability. Understanding the establishment and maintenance of these marks, along with their misregulation in pathologies is thus a major focus in the field. While we have learned a great deal about the enzymes regulating histone modifications on nucleosomal histones, much less is known about the mechanisms establishing modifications on soluble newly synthesized histones. This includes methylation of lysine 9 on histone H3 (H3K9), a mark that primes the formation of heterochromatin, a critical chromatin landmark for genome stability. Here, we report that H3K9 mono- and dimethylation is imposed during translation by the methyltransferase SetDB1. We discuss the importance of these results in the context of heterochromatin establishment and maintenance and new therapeutic opportunities in pathologies where heterochromatin is perturbed.

Further mulinane diterpenoids from Azorella compacta.

OBJECTIVES: The chemical study of a dichloromethane extract from Azorella compacta was directed to the isolation of characteristic mulinane and azorellane diterpenoids in order to determine their gastroprotective activity. METHODS: Usual chromatographic techniques on the extract led to the isolation of 12 compounds, which were identified by their spectroscopic properties. The HCl/ethanol-induced gastric lesions model in mice was used to determine the gastroprotective activity. KEY FINDINGS: The new diterpenoids, 13ß-hydroxymulinane (1), mulin-11,13-dien-20-ol (2), 13α-methoxyazorellanol (3) and mulin-11,13-dien-18-acetoxy-16,20-dioic acid (12) were isolated from A. compacta. The known diterpenoids mulin-11,13-dien-20-oic acid (4), 13α-hydroxyazorellane (5), 13ß-hydroxyazorellane (6), mulinic acid (7), mulinolic acid (8) and azorellanol (9), and the aromatic compounds 5,7-dihydroxychromone (10) and isoflavonoid biochanin A (11), were also obtained from the extract. Compounds 6, 9 and 12 at 20 mg/kg reduced gastric lesions by 69%, 71% and 73%, respectively, being statistically similar to lansoprazole at the same dose. CONCLUSIONS: The results corroborate the intraspecific chemical variations detected previously in specimens of A. compacta collected at different Chilean latitudes. A high concentration of azorellanol (9) could account in part for some of the therapeutic properties attributed to this species, in particular in ulcer treatment. Most of the mulinane and azorellane diterpenoids isolated in this study showed relevant gastroprotective activity at a low dose in the bioassay.

Sequential establishment of marks on soluble histones H3 and H4.

Much progress has been made concerning histone function in the nucleus; however, following their synthesis, how their marking and subcellular trafficking are regulated remains to be explored. To gain an insight into these issues, we focused on soluble histones and analyzed endogenous and tagged H3 histones in parallel. We distinguished six complexes that we could place to account for maturation events occurring on histones H3 and H4 from their synthesis onward. In each complex, a different set of chaperones is involved, and we found specific post-translational modifications. Interestingly, we revealed that histones H3 and H4 are transiently poly(ADP-ribosylated). The impact of these marks in histone metabolism proved to be important as we found that acetylation of lysines 5 and 12 on histone H4 stimulated its nuclear translocation. Furthermore, we showed that, depending on particular histone H3 modifications, the balance in the presence of the different translocation complexes changes. Therefore, our results enabled us to propose a regulatory means of these marks for controlling cytoplasmic/nuclear shuttling and the establishment of early modification patterns.

Reparación de hernia ventral connsecuente a la laparostomía / Repair of ventral hernia secondary to laparostomy

Se presenta una serie de casos de corrección de laparostomía en el Hospital Universitario de La Samaritana, Bogotá, Colombia, mediante la técnica de separación de componentes de la pared abdominal en el periodo comprendido entre junio de 2001 y diciembre de 2002.Es una técnica que utiliza incisiones de relajación y construcción de colgajos fasciomusculares para la corrección de grandes defectos en la pared abdominal, mediante la cual se evita el uso de prótesis.Se corrigieron defectos que oscilaban entre 14 - 18 cm de diámetro y 20 - 26 cm de longitud; sólo en un caso fue necesario utilizar malla por no poder cubrir completamente el defecto. Se presentó una reproducción en un paciente en quien se encontró además un tumor renal, lo cual puede explicar un aumento adicional de la presión intraabdominal. No hubo cambios importantes ni en las resistencias de la vía aérea ni en la presión intraabdominal. Como complicación mayor, un paciente falleció luego de presentar sepsis de origen abdominal por dehiscencia de anastomosis colocolónica realizada en el mismo tiempo quirúrgico y como complicaciones menores, algunos seromas e infección superficial de sitio operatorio.En conclusión se considera, una técnica útil en casos seleccionados que presenta ventajas frente al uso de prótesis y las posibles complicaciones asociadas a estas

Piperazine N-substituted naphthyridines, pyridothienopyrimidines and pyridothienotriazines: new antiprotozoals active against Philasterides dicentrarchi.

New antiprotozoals active against Philasterides dicentrarchi, the causative agent of scuticociliatosis in farmed turbot and Black Sea bass-bream, have been synthesised and tested. The most active compounds posses a piperazine ring, generally N-bonded to the heterocycle, and are the 1,8-naphthyridines, 2f and 5o, the pyridothienopyrimidine (7), and the pyridothienotriazines, 8, 9, 12d, 12f, 12h, 12m and 12k. Pyridothienotriazine (12k) presents the same activity (Lethal Dose, LD=0.8/1.5 mg L(-1)) as the well-known antiparasitics niclosamide and oxyclozanide.

Diagnóstico molecular prenatal de fibrosis quística: reporte de tres casos / Prenatal diagnosis of cystic fibrosis: report of three cases

La fibrosis quística (FQ) es una enfermedad autosómica recesiva severa, causada por múltiples mutaciones en el gen RCTFQ. La mutación más frecuente en el mundo es la AF508, que consiste en la delección del codón que codifica a la fenilalanina en la posición 508. En este trabajo se presentan los primeros casos venezolanos de diagnóstico prenatal molecular en parejas de alto riesgo para tener descendencia con FQ. El diagnóstico molecular de la mutación AF508 se realizó en ADN extraído directamente de amnioticos o de células cultivadas y la aplicación de la Reacción de la Polimerasa (RCP) y electroforesis en gel de poliacrilamida. En los dos primeros casos, los fetos fueron homocigotos para el alelo AF508 y el tercer feto presentaba un alelo AF508, descartándose la homocigosis del alelo normal. El asesoramiento genético prenatal a estas parejas permitió que tomaran decisiones reproductivas objetivas en base al conocimiento del genotipo fetal, lo cual solo es posible con la aplicación de estas técnicas para el análisis del genoma