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.

2,3,7,8-Tetrachlorodibenzo-p-dioxin and kynurenine induce Parkin expression in neuroblastoma cells through different signaling pathways mediated by the aryl hydrocarbon receptor.

Parkin regulates protein degradation and mitophagy in dopaminergic neurons. Deficiencies in Parkin expression or function lead to cellular stress, cell degeneration, and the death of dopaminergic neurons, which promotes Parkinson's disease. In contrast, Parkin overexpression promotes neuronal survival. Therefore, the mechanisms of Parkin upregulation are crucial to understand. We describe here the molecular mechanism of AHR-mediated Parkin regulation in human SH-SY5Y neuroblastoma cells. Specifically, we report that the human Parkin gene (PRKN) is transcriptionally upregulated by the aryl hydrocarbon receptor (AHR) through two different selective ligand-dependent pathways. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a stress-inducing AHR ligand, indirectly promotes PRKN transcription by inducing ATF4 expression via TCDD-mediated endoplasmic reticulum (ER) stress. In contrast, kynurenine, a nontoxic AHR agonist, induces PRKN transcription by promoting AHR binding to the PRKN promoter without activating ER stress. Our results demonstrate that AHR activation may be a potential pharmacological pathway to induce human Parkin, but such a strategy must carefully consider the choice of AHR ligand to avoid neurotoxic side effects.

Evolution of a theory of mind.

Even though the Theory of Mind in upper primates has been under investigation for decades, how it may evolve remains an open problem. We propose here an evolutionary game theoretical model where a finite population of individuals may use reasoning strategies to infer a response to the anticipated behavior of others within the context of a sequential dilemma, i.e., the Centipede Game. We show that strategies with bounded reasoning evolve and flourish under natural selection, provided they are allowed to make reasoning mistakes and a temptation for higher future gains is in place. We further show that non-deterministic reasoning co-evolves with an optimism bias that may lead to the selection of new equilibria, closely associated with average behavior observed in experimental data. This work reveals both a novel perspective on the evolution of bounded rationality and a co-evolutionary link between the evolution of Theory of Mind and the emergence of misbeliefs.

A whole-cell hypersensitive biosensor for beta-lactams based on the AmpR-AmpC regulatory circuit from the Antarctic Pseudomonas sp. IB20.

Detecting antibiotic residues is vital to minimize their impact. Yet, existing methods are complex and costly. Biosensors offer an alternative. While many biosensors detect various antibiotics, specific ones for beta-lactams are lacking. To address this gap, a biosensor based on the AmpC beta-lactamase regulation system (ampR-ampC) from Pseudomonas sp. IB20, an Antarctic isolate, was developed in this study. The AmpR-AmpC system is well-conserved in the genus Pseudomonas and has been extensively studied for its involvement in peptidoglycan recycling and beta-lactam resistance. To create the biosensor, the ampC coding sequence was replaced with the mCherry fluorescent protein as a reporter, resulting in a transcriptional fusion. This construct was then inserted into Escherichia coli SN0301, a beta-lactam hypersensitive strain, generating a whole-cell biosensor. The biosensor demonstrated dose-dependent detection of penicillins, cephalosporins and carbapenems. However, the most interesting aspect of this work is the high sensitivity presented by the biosensor in the detection of carbapenems, as it was able to detect 8 pg/mL of meropenem and 40 pg/mL of imipenem and reach levels of 1-10 ng/mL for penicillins and cephalosporins. This makes the biosensor a powerful tool for the detection of beta-lactam antibiotics, specifically carbapenems, in different matrices.

Geographical approach analysis of the impact of air pollution on newborn intrauterine growth and cord blood DNA damage in Mexico City.

BACKGROUND: Few epidemiologic studies have focused on the specific source of ambient air pollution and adverse health effects in early life. Here, we investigated whether air pollutants from different emission sources were associated with decreased birth anthropometry parameters and increased DNA adduct formation in mother-child pairs residing in the Mexico City Metropolitan Area (MCMA). METHODS: This cross-sectional study included 190 pregnant women recruited during their last trimester of pregnancy from two hospitals at MCMA, and a Modeling Emissions Inventory (MEI) to calculate exposure to ambient air pollutants from different emissions sources (area, point, mobile, and natural) for two geographical buffers 250 and 750 m radii around the participants households. RESULTS: Contaminants were positively correlated with umbilical cord blood (UCB) adducts, but not with maternal blood (MB) adducts. PM10 emissions (area and point sources, overall emissions), PM2.5 (point sources), volatile organic compounds (VOC), total organic compounds (TOC) from point sources were positively correlated with UCB adducts. Air pollutants emitted from natural sources were correlated with a decrease in MB and UCB adducts. PM10 and PM2.5 were correlated (p < 0.05) with a decrease in birth weight (BW), birth length (BL) and gestational age at term (GA). In multivariate analyses adjusted for potential confounders, PM10 was associated with an increase in UCB adducts. PM10 and PM2.5 from overall emissions were associated with a decrease in BW, BL and GA at term. IMPACT: Results suggested higher susceptibility of newborns compared to mothers to damage related to ambient air pollution. PMs are associated with birth anthropometry parameters and DNA damage in adjusted models, highlighting the need for more strict regulation of PM emissions.

Ongoing diversification of the global fish pathogen Piscirickettsia salmonis through genetic isolation and transposition bursts.

The management of bacterial pathogens remains a key challenge of aquaculture. The marine gammaproteobacterium Piscirickettsia salmonis is the etiological agent of piscirickettsiosis and causes multi-systemic infections in different salmon species, resulting in considerable mortality and substantial commercial losses. Here, we elucidate its global diversity, evolution, and selection during human interventions. Our comprehensive analysis of 73 closed, high quality genome sequences covered strains from major outbreaks and was supplemented by an analysis of all P. salmonis 16S rRNA gene sequences and metagenomic reads available in public databases. Genome comparison showed that Piscirickettsia comprises at least three distinct, genetically isolated species of which two showed evidence for continuing speciation. However, at least twice the number of species exist in marine fish or seawater. A hallmark of Piscirickettsia diversification is the unprecedented amount and diversity of transposases which are particularly active in subgroups undergoing rapid speciation and are key to the acquisition of novel genes and to pseudogenization. Several group-specific genes are involved in surface antigen synthesis and may explain the differences in virulence between strains. However, the frequent failure of antibiotic treatment of piscirickettsiosis outbreaks cannot be explained by horizontal acquisition of resistance genes which so far occurred only very rarely. Besides revealing a dynamic diversification of an important pathogen, our study also provides the data for improving its surveillance, predicting the emergence of novel lineages, and adapting aquaculture management, and thereby contributes towards the sustainability of salmon farming.

Interplay between Estrogen, Kynurenine, and AHR Pathways: An immunosuppressive axis with therapeutic potential for breast cancer treatment.

Breast cancer is one of the most common malignancies among women worldwide. Estrogen exposure via endogenous and exogenous sources during a lifetime, together with environmental exposure to estrogenic compounds, represent the most significant risk factor for breast cancer development. As breast tumors establish, multiple pathways are deregulated. Among them is the aryl hydrocarbon receptor (AHR) signaling pathway. AHR, a ligand-activated transcription factor associated with the metabolism of polycyclic aromatic hydrocarbons and estrogens, is overexpressed in breast cancer. Furthermore, AHR and estrogen receptor (ER) cross-talk pathways have been observed. Additionally, the Tryptophan (Trp) catabolizing enzymes indolamine-2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO) are overexpressed in breast cancer. IDO/TDO catalyzes the formation of Kynurenine (KYN) and other tryptophan-derived metabolites, which are ligands of AHR. Once KYN activates AHR, it stimulates the expression of the IDO enzyme, increases the level of KYN, and activates non-canonical pathways to control inflammation and immunosuppression in breast tumors. The interplay between E2, AHR, and IDO/TDO/KYN pathways and their impact on the immune system represents an immunosuppressive axis on breast cancer. The potential modulation of the immunosuppressive E2-AHR-IDO/TDO/KYN axis has aroused great expectations in oncotherapy. The present article will review the mechanisms implicated in generating the immunosuppressive axis E2-AHR-IDO/TDO/KYN in breast cancer and the current state of knowledge as a potential therapeutic target.

Heavy Metal Pollution From a Major Earthquake and Tsunami in Chile Is Associated With Geographic Divergence of Clinical Isolates of Methicillin-Resistant Staphylococcus aureus in Latin America.

Methicillin-resistant Staphylococcus aureus (MRSA) is a priority pathogen listed by the World Health Organization. The global spread of MRSA is characterized by successive waves of epidemic clones that predominate in specific geographical regions. The acquisition of genes encoding resistance to heavy-metals is thought to be a key feature in the divergence and geographical spread of MRSA. Increasing evidence suggests that extreme natural events, such as earthquakes and tsunamis, could release heavy-metals into the environment. However, the impact of environmental exposition to heavy-metals on the divergence and spread of MRSA clones has been insufficiently explored. We assess the association between a major earthquake and tsunami in an industrialized port in southern Chile and MRSA clone divergence in Latin America. We performed a phylogenomic reconstruction of 113 MRSA clinical isolates from seven Latin American healthcare centers, including 25 isolates collected in a geographic area affected by an earthquake and tsunami that led to high levels of heavy-metal environmental contamination. We found a divergence event strongly associated with the presence of a plasmid harboring heavy-metal resistance genes in the isolates obtained in the area where the earthquake and tsunami occurred. Moreover, clinical isolates carrying this plasmid showed increased tolerance to mercury, arsenic, and cadmium. We also observed a physiological burden in the plasmid-carrying isolates in absence of heavy-metals. Our results are the first evidence that suggests that heavy-metal contamination, in the aftermath of an environmental disaster, appears to be a key evolutionary event for the spread and dissemination of MRSA in Latin America.

[Cost-effectiveness of treatment of type 2 diabetes mellitus in México]. / Costo-efectividad del tratamiento de la diabetes mellitus tipo 2 en México.

Background: Type 2 Diabetes Mellitus (DM2) is a public health and socioeconomic problem, generating direct medical costs for its treatment. Objective: To analyze the cost-effectiveness of monotherapy and bitherapy treatments in patients with DM2. Methods: Cost-effectiveness, observational, ambispective, cross-sectional and analytical analysis of files in a first level medical unit. The data in the cost matrix was executed with the Office Excel 2010 program; the most prescribed drug was identified and compared with monotherapy and bitherapy. Results: The annual direct medical costs of the total population were drug cost $118,561.70MN, hospitalization cost $243,756.00MN, consultation cost $327,414.00MN and clinical trial cost $2416.79MN, obtaining an annual total of $692,148.58MN. metformin was the most indicated in monotherapy (88.4%) and as standard therapy it has higher cost-effectiveness compared to glibenclamide. In bitherapy it was metformin/glibenclamide (35.7%) versus the therapeutics of metformin/NPH insulin, metformin/insulin glargine and metformin/dapagliflozin, which had a better cost-effective result, with an incremental cost effectiveness of -$1,128,428.50MN, -$34,365.00 MN, -$119,848.97MN respectively. Conclusions: Metformin presented a better cost-effectiveness ratio in monotherapy, while in bitherapy it was the metformin/NPH insulin association.

Introducción: La Diabetes Mellitus tipo 2 (DM2) es un problema de salud pública y socioeconómico, tanto por su alta incidencia como por la generación de los costos médicos directos para su tratamiento. Objetivo: Analizar el costo-efectividad de los tratamientos en monoterapia y biterapia en pacientes con DM2. Métodos: Análisis costo-efectividad, observacional, ambispectivo, transversal y analítico. Análisis de expedientes en una unidad médica de primer nivel. Se ejecutaron los datos en la matriz de costos con el programa Office Excel 2010; se identificó el fármaco más prescrito, se comparó con monoterapia y biterapia. Resultados: Los costos médicos directos anuales del total de la población fueron: costo del medicamento $118,561.70MN, costo por hospitalización $243,756.00MN, costo por consultas $ 327,414.00MN y costo por estudios clínicos $2416.79MN, obteniendo un total anual de $692,148.58MN. La metformina fue la más indicada en monoterapia (88.4%) y como terapéutica estándar tiene mayor costo-efectividad comparada con la glibenclamida. En biterapia fue metformina/glibenclamida (35.7%) versus las terapéuticas de metformina/insulina NPH, metformina/insulina glargina y metformina/dapagliflozina, las cuales tuvieron un resultando más costo-efectivo, con un costo efectividad incremental de -$1,128,428.50MN, -$34,365.00MN, -$119,848.97MN respectivamente. Conclusiones: La metformina presento mejor relación costo efectividad en monoterapia, mientras que en biterapia fue la asociación metformina/Insulina NPH.

Mobile genetic elements drive the multidrug resistance and spread of Salmonella serotypes along a poultry meat production line.

The presence of mobile genetic elements in Salmonella isolated from a chicken farm constitutes a potential risk for the appearance of emerging bacteria present in the food industry. These elements contribute to increased pathogenicity and antimicrobial resistance through genes that are related to the formation of biofilms and resistance genes contained in plasmids, integrons, and transposons. One hundred and thirty-three Salmonella isolates from different stages of the production line, such as feed manufacturing, hatchery, broiler farm, poultry farm, and slaughterhouse, were identified, serotyped and sequenced. The most predominant serotype was Salmonella Infantis. Phylogenetic analyses demonstrated that the diversity and spread of strains in the pipeline are serotype-independent, and that isolates belonging to the same serotype are very closely related genetically. On the other hand, Salmonella Infantis isolates carried the pESI IncFIB plasmid harboring a wide variety of resistance genes, all linked to mobile genetic elements, and among carriers of these plasmids, the antibiograms showed differences in resistance profiles and this linked to a variety in plasmid structure, similarly observed in the diversity of Salmonella Heidelberg isolates carrying the IncI1-Iα plasmid. Mobile genetic elements encoding resistance and virulence genes also contributed to the differences in gene content. Antibiotic resistance genotypes were matched closely by the resistance phenotypes, with high frequency of tetracycline, aminoglycosides, and cephalosporins resistance. In conclusion, the contamination in the poultry industry is described throughout the entire production line, with mobile genetic elements leading to multi-drug resistant bacteria, thus promoting survival when challenged with various antimicrobial compounds.

Robust Motor Imagery Tasks Classification Approach Using Bayesian Neural Network.

The development of Brain-Computer Interfaces based on Motor Imagery (MI) tasks is a relevant research topic worldwide. The design of accurate and reliable BCI systems remains a challenge, mainly in terms of increasing performance and usability. Classifiers based on Bayesian Neural Networks are proposed in this work by using the variational inference, aiming to analyze the uncertainty during the MI prediction. An adaptive threshold scheme is proposed here for MI classification with a reject option, and its performance on both datasets 2a and 2b from BCI Competition IV is compared with other approaches based on thresholds. The results using subject-specific and non-subject-specific training strategies are encouraging. From the uncertainty analysis, considerations for reducing computational cost are proposed for future work.

A Comparison of Deep Neural Networks for Monocular Depth Map Estimation in Natural Environments Flying at Low Altitude.

Currently, the use of Unmanned Aerial Vehicles (UAVs) in natural and complex environments has been increasing, because they are appropriate and affordable solutions to support different tasks such as rescue, forestry, and agriculture by collecting and analyzing high-resolution monocular images. Autonomous navigation at low altitudes is an important area of research, as it would allow monitoring parts of the crop that are occluded by their foliage or by other plants. This task is difficult due to the large number of obstacles that might be encountered in the drone's path. The generation of high-quality depth maps is an alternative for providing real-time obstacle detection and collision avoidance for autonomous UAVs. In this paper, we present a comparative analysis of four supervised learning deep neural networks and a combination of two for monocular depth map estimation considering images captured at low altitudes in simulated natural environments. Our results show that the Boosting Monocular network is the best performing in terms of depth map accuracy because of its capability to process the same image at different scales to avoid loss of fine details.

Detección y cuantificación de SARS-CoV-2 en plantas de tratamiento de aguas residuales de diferentes ciudades de Chile: hacia la implementación de una vigilancia centinela permanente

Introducción: La cuantificación de SARS-CoV-2 en aguas residuales es una herramienta que permite determinar la tendencia de la circulación viral en un área geográfica determinada. Objetivo: Cuantificar el virus SARS-CoV-2 en 15 plantas de tratamiento de aguas residuales en diferentes ciudades de Chile para establecer una comparación con las variables de: i) casos activos por cada 100.000 habs.; ii) positividad diaria (casos nuevos); y iii) fases del plan de confinamiento. Metodología: SARS-CoV-2 se concentró a partir de muestras de aguas residuales. Para obtener el número de genomas del virus por litro se realizó una cuantificación absoluta utilizando qRT-PCR. Resultados: Entre enero y junio de 2021 se procesaron 253 muestras, siendo todas positivas para la presencia del virus. Asimismo, se logró determinar que la tasa de casos activos por cada 100.000 habs. es la variable que mejor se ajusta a las tendencias obtenidas con la cuantificación de la carga viral en las aguas residuales. Conclusiones: La cuantificación de SARS-CoV-2 en las aguas residuales de manera permanente es una herramienta eficiente para determinar la tendencia del virus en un área geográfica determinada y, en conjunto con una vigilancia genómica, puede constituirse en una vigilancia centinela ideal generando alertas sobre futuros brotes.

Background: The quantification of SARS-CoV-2 in wastewater is a tool that allows determining the trend of viral circulation in a particular geographical area. Aim: To quantify the SARS-CoV-2 virus in 15 wastewater treatment plants in different Chilean cities to establish a comparison with the variables of: i) Active cases per 100,000 inhabitants; ii) daily positivity (novel cases); and iii) phases of the lockdown strategy. Methods: SARS-CoV-2 was concentrated from wastewater samples. To obtain the number of virus genomes per liter, absolute quantification was performed using qRT-PCR. Results: Between January and June 2021, 253 samples were processed, all of which were positive for the presence of the virus. Likewise, it will be determined that the rate of active cases per 100,000 inhabitants is the variable that best fits the trends obtained with the quantification of the viral load in wastewater. Conclusions: The quantification of SARS-CoV-2 in wastewater as a continuous strategy is an efficient tool to determine the trend of the viral circulation in a delimited geographical area and, combined with genomic surveillance, it can constitute an ideal sentinel surveillance alert on future outbreaks.

Role of the multi-drug efflux systems on the baseline susceptibility to ceftazidime/avibactam and ceftolozane/tazobactam in clinical isolates of non-carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is one of the pathogens that urgently needs new drugs and new alternatives for its control. The primary strategy to combat this bacterium is combining treatments of beta-lactam with a beta-lactamase inhibitor. The most used combinations against P. aeruginosa are ceftazidime/avibactam (CZA) and ceftolozane/tazobactam (C/T). Although mechanisms leading to CZA and C/T resistance have already been described, among which are the resistance-nodulation-division (RND) efflux pumps, the role that these extrusion systems may play in CZA, and C/T baseline susceptibility of clinical isolates remains unknown. For this purpose, 161 isolates of non-carbapenemase-producing (Non-CP) CRPA were selected, and susceptibility tests to CZA and C/T were performed in the presence and absence of the RND efflux pumps inhibitor, Phenylalanine-arginine ß-naphthylamide (PAßN). In the absence of PAßN, C/T showed markedly higher activity against Non-CP-CRPA isolates than observed for CZA. These results were even more evident in isolates classified as extremely-drug resistant (XDR) or with difficult-to-treat resistance (DTR), where CZA decreased its activity up to 55.2% and 20.0%, respectively, whereas C/T did it up to 82.8% (XDR), and 73.3% (DTR). The presence of PAßN showed an increase in both CZA (37.6%) and C/T (44.6%) activity, and 25.5% of Non-CP-CRPA isolates increased their susceptibility to these two combined antibiotics. However, statistical analysis showed that only the C/T susceptibility of Non-CP-CRPA isolates was significantly increased. Although the contribution of RND activity to CZA and C/T baseline susceptibility was generally low (two-fold decrease of minimal inhibitory concentrations [MIC]), a more evident contribution was observed in a non-minor proportion of the Non-CP-CRPA isolates affected by PAßN [CZA: 25.4% (15/59); C/T: 30% (21/70)]. These isolates presented significantly higher MIC values for C/T. Therefore, we conclude that RND efflux pumps are participating in the phenomenon of baseline susceptibility to CZA and, even more, to C/T. However, the genomic diversity of clinical isolates is so great that deeper analyzes are necessary to determine which elements are directly involved in this phenomenon.

Isolation of an Extensively Drug-Resistant Pseudomonas aeruginosa exoS+/O4 Strain Belonging to the "High-Risk" Clone ST654 and Coproducer of NDM-1 and the Novel VIM-80.

The aim of this study was to investigate the genomic features of an extensively drug-resistant (XDR) Pseudomonas aeruginosa isolate (P-469) emerging in Chile. Antibiotic susceptibility was determined by disk diffusion and "colistin agar" test. Whole-genome sequencing (WGS) was performed by the Illumina NextSeq 2000 platform, and epidemiologically and clinically relevant data (i.e., sequence-type, serotype, mobile genetic elements, virulome, resistome, plasmidome, prophages, and CRISPR-Cas systems) were retrieved using multiple bioinformatic tools. The P-469 strain displayed an XDR profile, remaining susceptible to colistin. Genomic analysis revealed that this isolate belonged to the "high-risk" clone ST654 (CC654), serotype O4, and genotype exoS+. Strikingly, two CRISPR-Cas systems, five intact prophages sequences, and a broad resistome that included blaNDM-1 and the novel blaVIM-80 carbapenemase genes were predicted. Our results revealed the genomic characteristics of P. aeruginosa belonging to the high-risk clone ST654/O4 coproducing NDM-1 and VIM-80 in Chile, supporting that genomic surveillance is necessary to track the emergence and spread of epidemiologically successful WHO's critical priority pathogens in order to prevent their rapid dissemination.

Acquisition of resistance to ceftazidime-avibactam during infection treatment in Pseudomonas aeruginosa through D179Y mutation in one of two blaKPC-2 gene copies without losing carbapenem resistance.

Ceftazidime/Avibactam (CAZ/AVI) is frequently used to treat KPC-producing Pseudomonas aeruginosa (KPC-PA) and Enterobacterales. CAZ/AVI resistance is driven by several mechanisms. In P. aeruginosa this mainly occurs through alteration of AmpC, porins, and/or efflux pump overexpression, whereas in Enterobacterales it frequently occurs through D179Y substitution in the active site of KPC enzyme. This aminoacid change abolishes AVI binding to the KPC active site, hence inhibition is impaired. However, this substitution also decreases KPC-mediated resistance to carbapenems ("see-saw" effect). The goal of this work was to characterize the in vivo acquisition of CAZ/AVI resistance through D179Y substitution in a KPC-PA isolated from a hospitalized patient after CAZ/AVI treatment. Two KPC-PA isolates were obtained. The first isolate, PA-1, was obtained before CAZ/AVI treatment and was susceptible to CAZ/AVI. The second isolate, PA-2, was obtained after CAZ/AVI treatment and exhibited high-level CAZ/AVI resistance. Characterization of isolates PA-1 and PA-2 was performed through short and long-read whole genome sequencing analysis. The hybrid assembly showed that PA-1 and PA-2A had a single plasmid of 54,030 bp, named pPA-1 and pPA-2 respectively. Each plasmid harbored two copies of the bla KPC-containing Tn4401b transposon. However, while pPA-1 carried two copies of bla KPC-2, pPA-2 had one copy of bla KPC-2 and one copy of bla KPC-33, the allele with the D179Y substitution. Interestingly, isolate PA-2 did not exhibit the "see-saw" effect. The bla KPC-33 allele was detected only through hybrid assembly using a long-read-first approach. The present work describes a KPC-PA isolate harboring a plasmid-borne CAZ/AVI resistance mechanism based on two copies of bla KPC-2-Tn4401b and D179Y mutation in one of them, that is not associated with loss of resistance to carbapenems. These findings highlight the usefulness of a fine-tuned combined analysis of short and long-read data to detect similar emerging resistance mechanisms.

Cancer Care Access in Chile's Vulnerable Populations During the COVID-19 Pandemic.

Objectives. To examine the COVID-19 pandemic's impact on cancer care access in Chile, analyzing differential effects by insurance type, gender, and age. Methods. We conducted a quasi-experimental study using interrupted time series analysis. We used multiple data sources for a broad evaluation of cancer-related health care utilization from January 2017 to December 2020. We fit negative binomial models by population groups for a range of services and diagnoses. Results. A sharp drop in oncology health care utilization in March was followed by a slow, incomplete recovery over 2020. Cumulative cancer-related services, diagnostic confirmations, and sick leaves were reduced by one third in 2020; the decrease was more pronounced among women and the publicly insured. Early diagnosis was missed in 5132 persons with 4 common cancers. Conclusions. The pandemic stressed the Chilean health system, decreasing access to essential services, with a profound impact on cancer care. Oncology service reductions preceded large-scale lockdowns and supply-side disruptions. Importantly, not all population groups were equally affected, with patterns suggesting that gender and socioeconomic inequalities were exacerbated. (Am J Public Health. 2022;112(S6):S591-S601. https://doi.org/10.2105/AJPH.2021.306587).

[Cancer care access in Chile's vulnerable populations during the COVID-19 pandemicAcesso a tratamento de câncer em populações vulneráveis no Chile durante a pandemia de COVID-19]. / Acceso a la atención del cáncer en los grupos vulnerables de Chile durante la pandemia de COVID-19.

Objectives: To examine the COVID-19 pandemic's impact on cancer care access in Chile, analyzing differential effects by insurance type, gender, and age. Methods: We conducted a quasi-experimental study using interrupted time series analysis. We used multiple data sources for a broad evaluation of cancer-related health care utilization from January 2017 to December 2020. We fit negative binomial models by population groups for a range of services and diagnoses. Results: A sharp drop in oncology health care utilization in March was followed by a slow, incomplete recovery over 2020. Cumulative cancer-related services, diagnostic confirmations, and sick leaves were reduced by one third in 2020; the decrease was more pronounced among women and the publicly insured. Early diagnosis was missed in 5132 persons with 4 common cancers. Conclusions: The pandemic stressed the Chilean health system, decreasing access to essential services, with a profound impact on cancer care. Oncology service reductions preceded large-scale lockdowns and supply-side disruptions. Importantly, not all population groups were equally affected, with patterns suggesting that gender and socioeconomic inequalities were exacerbated.

Objetivos: Examinar o impacto da pandemia de COVID-19 no acesso a tratamento de câncer no Chile, analisando efeitos diferenciais por tipo de cobertura de assistência à saúde, gênero e idade. Métodos: Realizamos um estudo quase-experimental utilizando análise de séries temporais interrompidas. A partir de várias fontes de dados, efetuamos uma avaliação abrangente da utilização de atenção à saúde relacionada ao câncer, de janeiro de 2017 a dezembro de 2020. Ajustamos modelos binomiais negativos por grupos populacionais a vários tipos de serviços e diagnósticos. Resultados: Uma queda acentuada no uso da assistência médica oncológica em março foi seguida por uma recuperação lenta e incompleta ao longo de 2020. Cumulativamente, a utilização de serviços oncológicos, as confirmações de diagnóstico e os afastamentos do trabalho por doença foram reduzidos em um terço em 2020. Essa redução foi mais pronunciada em mulheres e usuários do sistema público de saúde. No total, 5132 pessoas com 4 cânceres comuns não foram diagnosticadas precocemente. Conclusões: A pandemia impôs pressão sobre o sistema de saúde chileno, reduzindo o acesso a serviços essenciais e causando um profundo impacto no tratamento do câncer. As reduções na prestação de serviços de oncologia precederam os lockdowns em larga escala e as interrupções na oferta de suprimentos. É importante ressaltar que nem todos os grupos populacionais foram igualmente afetados e os padrões observados sugerem que as desigualdades de gênero e socioeconômicas foram exacerbadas.