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Background : Lefamulin, a pleuromutilin antibiotic approved for community-acquired bacterial pneumonia (CABP), was evaluated for microbiological efficacy in a prespecified pooled analysis of LEAP 1 and 2 phase 3 clinical trial data in patients with CABP. Methods : In LEAP 1, adults (Pneumonia Outcomes Research Team [PORT] risk class III‒V) received intravenous (IV) lefamulin 150 mg every 12 hours (q12h; 5‒7 days) or moxifloxacin 400 mg every 24 hours (q24h; 7 days), with optional IV-to-oral switch. In LEAP 2, adults (PORT II‒IV) received oral lefamulin 600 mg q12h (5 days) or moxifloxacin 400 mg q24h (7 days). Primary outcomes were early clinical response (ECR) 96±24 hours after treatment start and investigator assessment of clinical response (IACR) 5‒10 days after last dose. Secondary outcomes included ECR and IACR in patients with a baseline CABP pathogen (detected via culture, urinary antigen test, serology, and/or real-time PCR). Results : Baseline CABP pathogens were detected in 709/1289 patients (55.0% [microbiological intent-to-treat population]). The most frequently identified pathogens in this population were Streptococcus pneumoniae (61.9% of patients) and Haemophilus influenzae (29.9%); 25.1% had atypical pathogens and 33.1% had polymicrobial infections. Pathogens were identified most frequently by PCR from sputum, followed by culture from respiratory specimens. In patients with baseline CABP pathogens, ECR rates were 89.3% (lefamulin) and 93.0% (moxifloxacin); IACR success rates were 83.2% and 86.7%, respectively. Results were consistent across CABP pathogens, including drug-resistant isolates and polymicrobial infections. Conclusions : Lefamulin is a valuable IV and oral monotherapy option for empiric and directed CABP treatment in adults.

BACKGROUND We assessed nasopharyngeal pneumococcal carriage in Andean Kichwa children, the largest Amerindian indigenous population in the Ecuadorian Andes. All children in our study had been vaccinated with the 10-valent pneumococcal vaccine (PCV10). METHODS Nasopharyngeal swabs from 63 families, 100 children

Objective The aim of this study was to analyze the influence of social determinants on changes in dietary habits before and after diagnosis of breast cancer in women (Barcelona, 2003-2013). Methods We performed a cohort study with 2,235 women diagnosed with breast cancer. The information was obtained from an ad hoc questionnaire based on recommendations from the Spanish Society of Community Nutrition. We conducted a descriptive bivariate analysis and fit logistic regression models. The dependent variable was the change in dietary habits (food groups) and the independent variables were a selection of social and clinical variables (age, social class, cohabitation, years since diagnosis, history of replaces, and treatment with chemotherapy). Results While 5.8% of women followed a healthy diet (consumption of vegetables, fruits, farinaceous, lean meat, and seafood) before diagnosis, 9.5% did so after diagnosis. We observed statistically significant changes in consumption of all food groups (p < 0.001) after diagnosis. The greatest change in consumption patterns was observed in women aged < 50 years and those from non-manual classes (high classes) [e.g., legume consumption: OR65 years = 2.9 (95% CI 1.78-4.81); ORnon-manual/manual = 2.5 (95% CI 1.38-4.36)]. The occurrence of relapses and chemotherapy was associated with greater changes in dietary habits. Conclusion Women with breast cancer change their eating habits after diagnosis, and these changes are conditioned by social and clinical determinants.

Background We systematically assessed benefits and harms of the use of ivermectin (IVM) in patients with coronavirus disease 2019 (COVID-19). Methods Published and preprint randomized controlled trials (RCTs) assessing the effects of IVM on adult patients with COVID-19 were searched until 22 March 2021 in 5 engines. Primary outcomes were all-cause mortality rate, length of hospital stay (LOS), and adverse events (AEs). Secondary outcomes included viral clearance and severe AEs (SAEs). The risk of bias (RoB) was evaluated using the Cochrane Risk of Bias 2.0 tool. Inverse variance random effect meta-analyses were performed, with quality of evidence (QoE) evaluated using GRADE methods. Results Ten RCTs (n = 1173) were included. The controls were the standard of care in 5 RCTs and placebo in 5. COVID-19 disease severity was mild in 8 RCTs, moderate in 1, and mild and moderate in 1. IVM did not reduce all-cause mortality rates compared with controls (relative risk [RR], 0.37 [95% confidence interval, .12–1.13]; very low QoE) or LOS compared with controls (mean difference, 0.72 days [95% confidence interval, −.86 to 2.29 days]; very low QoE). AEs, SAEs, and viral clearance were similar between IVM and control groups (low QoE for all outcomes). Subgroups by severity of COVID-19 or RoB were mostly consistent with main analyses; all-cause mortality rates in 3 RCTs at high RoB were reduced with IVM. Conclusions Compared with the standard of care or placebo, IVM did not reduce all-cause mortality, LOS, or viral clearance in RCTs in patients with mostly mild COVID-19. IVM did not have an effect on AEs or SAEs and is not a viable option to treat patients with COVID-19., Our systematic review of randomized controlled trials showed that ivermectin (vs control) did not reduce all-cause mortality, hospital stays, or viral clearance in patients with mostly mild coronavirus disease 2019 (COVID-19). Ivermectin is not a viable treatment option for COVID-19.

Clostridium perfringens forms biofilms and spores that are a source of food contamination. In this study, the antibacterial activities of Lactobacillus plantarum culture supernatants (LP-S), LP-S fractions, and the plant-derived compound epigallocatechin gallate (EG) were evaluated. Specifically, their effects on the viability and biofilm-forming ability of C. perfringens were assessed. Moreover, the expression of quorum sensing-regulated genes associated with the pathogenesis of this microorganism and that of genes involved in biofilm formation was also investigated. The results showed that both EG and the LP-S exerted bactericidal activity against all C. perfringens strains tested. The minimal bactericidal concentration (MBC) of EG was 75 µg/mL for all strains but ranged from 61 to 121 µg of total protein per mL for LP-S. EG exerted only minor effects on biofilm formation, whereas LP-S, particularly its 10 and 30 K fractions, significantly reduced the biofilm-forming ability of all the strains. The antibiofilm activity of LP-S was lost following preincubation with proteases, suggesting that it was mediated by a proteinaceous molecule. The treatment of C. perfringens with either EG or LP-S did not change the transcript levels of two CpAL (C. perfringens quorum-sensing Agr-like system)-related genes, agrB and agrD, which are known to be involved in the regulation of biofilms, suggesting that LP-S exerted its biofilm inhibitory activity downstream of CpAL signaling. In summary, we demonstrated the bactericidal activity of EG and LP-S against C. perfringens and antibiofilm activity of LP-S at a subinhibitory dose. Our results suggested that these compounds can be further explored for food safety applications to control agents such as C. perfringens.

Disseminated histoplasmosis (DH) is endemic in Latin America and the Caribbean where diagnostic tools are restricted. We carried-out a 1-year prospective cohort study at a referral hospital in São Paulo, Brazil. Participants had > or =18 years old, were hospitalized due to any indication and had CD4+ < 200 cells/µl. A urine commercial monoclonal Histoplasma galactomannan enzyme-linked immunosorbent assay (IMMY, Norman, OK, USA) and ‘in house’ Histoplasma blood nested PCR were performed in all cases. Probable/proven DH cases were defined according to international guidelines. Conventional mycological methods were available in routine conditions to investigate suspected DH cases. Treatment of participants followed the institutional routine. One-hundred six participants were included. Median age (interquartile range [IQR]) was 39.5 years (30.0–47.3) and 80 individuals (75.5%) were males. Median (IQR) CD4 cell count was 26.5 (9.4–89.3) cells/mm3. DH was diagnosed in 8/106 patients (7.5%). Antigen assay and/or PCR were positive in 4.7% (5/106) of patients. The antigen assay and/or PCR identified 37.5% (3/8) of DH cases, which had not been diagnosed with conventional mycological methods, but had clinical manifestations compatible with HD. In conclusion, the use of Histoplasma urine antigen and Histoplasma blood PCR guided by CD4 status contributed to the diagnosis of DH in hospitalized individuals. These assays were complementary to conventional mycologic methods and are urgently needed in our setting. Lay Summary In this prospective cohort study carried-out in a referral center in São Paulo, Brazil, we found a high frequency of AIDS-related disseminated histoplasmosis (8/106, 7.5%). We used urine antigen test and blood PCR assay to improve the diagnosis of this opportunistic disease.

There is scarce information about HIV-related cryptococcosis in the Brazilian Amazon basin where laboratory infrastructure is limited. The serum cryptococcal antigen (CrAg) lateral flow assay (LFA) has simplified diagnosis of cryptococcosis and is recommended for screening in advanced HIV disease. We evaluated the prevalence of cryptococcal antigenemia using finger-prick CrAg LFA in the Brazilian Amazon basin. We enrolled a prospective cohort of outpatients and hospitalized individuals with advanced HIV disease at two centers in Santarém Municipality, Northern Brazil. All individuals were 18 years old with advanced HIV disease, regardless of antiretroviral therapy (ART) status and with no prior or current history of confirmed cryptococcal meningitis. We tested CrAg LFA on finger-prick whole blood using an exact volume transfer pipette. From August 2018 to October 2019, 104 individuals were enrolled (outpatients 62 [60%] and hospitalized 42 [40%]). Median age was 38 years (interquartile range [IQR] 30-46), and 84 (81%) were male. Sixty-five (63%) individuals were ART-naïve. Prevalence of finger-prick CrAg LFA-positive was 10.6%; 95% CI, 5.4 to 18.1%. Prevalence of finger-prick CrAg LFA-positive among individuals without neurological symptoms was 6.0%; 95% CI, 1.7-14.6%. The number needed to test to detect one CrAg-positive individual was 9.4 persons (95% CI, 5.5-18.5). Prevalence of cryptococcal antigenemia using finger-prick whole blood CrAg LFA was high. Point-of-care approach was important for the diagnosis and screening of cryptococcosis in resource-limited settings. Screening and preemptive therapy strategy should be urgently implemented in individuals with advanced HIV disease in the Brazilian Amazon basin.This prospective cohort study was carried-out in the Brazilian Amazon basin. We used a cryptococcal rapid test in patients with AIDS. We included 104 participants, and 11 (10.6%) of them had positive results showing a high prevalence of cryptococcal antigenemia.

This systematic review evaluated the diagnostic accuracy of Xpert MTB/RIF to detect tuberculous meningitis (TBM).PubMed and five other databases were systematically searched through March 2019. All studies evaluating diagnostic accuracy of Xpert MTB/RIF on cerebrospinal fluid (CSF) samples were included. Reference standards were definitive or definite plus probable TBM. The quality of studies was assessed by the QUADAS-2 tool. We performed bivariate random-effects meta-analysis and calculated summary diagnostic statistics.We identified 30 studies (n = 3972 participants), including 5 cohort studies and 25 cross-sectional studies. Reference standards were definite TB (n = 28 studies) or definite plus probable TBM (n = 6 studies). The pooled Xpert MTB/RIF sensitivity was 85% (95% CI, 70-93%), and specificity was 98% (95% CI, 97-99%) with a negative likelihood ratio of 0.15 (95% CI, 0.04-0.27) for definite TBM. For probable TBM cases, pooled sensitivity was 81% (95% CI, 66-90%), and specificity was 99% (95% CI, 97-99%). For both reference standard types, meta-analyses showed a C-statistic area under the curve of 0.98. The QUADAS-2 tool revealed low risk of bias as well as low concerns regarding applicability. Methodological heterogeneity was high among studies.Xpert MTB/RIF showed high accuracy for TBM diagnosis, but a negative Xpert MTB/RIF test does not rule out TBM. Repeat Xpert testing may be necessary. In clinical practice, Xpert MTB/RIF adds speed and sensitivity when compared to classic TBM diagnostic methods or previous commercial nucleic acid amplification techniques. More studies and better strategies for rapidly confirming a diagnosis of TBM in children are urgently needed.Cette revue systématique a évalué la précision diagnostique de Xpert MTB/RIF pour détecter la méningite tuberculeuse (MTB). MÉTHODES: PubMed et cinq autres bases de données ont fait l'objet d'une recherche systématique jusqu'en mars 2019. Toutes les études évaluant la précision du diagnostic de Xpert MTB/RIF sur des échantillons de liquide céphalo-rachidien (LCR) ont été incluses. Les étalons de référence étaient des MTB définitives ou définitives et probables. La qualité des études a été évaluée par l'outil QUADAS-2. Nous avons effectué une méta-analyse des effets aléatoires bivariés et calculé des statistiques de résumés diagnostiques. RÉSULTATS: Nous avons identifié 30 études (n = 3.972 participants), dont 5 études de cohorte et 25 études transversales. Les étalons de référence étaient la TB définitive (n = 28 études) ou la MTB définitive et probable (n = 6 études). La sensibilité poolée Xpert MTB/RIF était de 85% (IC95%: 70-93%) et la spécificité était de 98% (IC95%: 97-99%) avec un rapport de vraisemblance négatif de 0,15 (IC95%: 0,04-0,27) pour la MTB définitive. Pour les cas probables de la MTB, la sensibilité poolée était de 81% (IC95%: 66-90%) et la spécificité était de 99% (IC95%: 97-99%). Pour les deux types d'étalons de référence, les méta-analyses ont montré une aire statistique C sous la courbe de 0,98. L'outil QUADAS-2 a révélé un faible risque de biais ainsi que de faibles préoccupations concernant l'applicabilité. L'hétérogénéité méthodologique était élevée parmi les études.Xpert MTB/RIF a montré une grande précision pour le diagnostic de la MTB, mais un test Xpert MTB/RIF négatif n'exclut pas la MTB. La répétition du tests Xpert peut être nécessaire. Dans la pratique clinique, Xpert MTB/RIF ajoute vitesse et sensibilité par rapport aux méthodes de diagnostic classiques de la MTB ou aux précédentes techniques d'amplification d'acide nucléique commerciales. Des études supplémentaires et de meilleures stratégies pour confirmer rapidement un diagnostic de MTB chez les enfants sont nécessaires d'urgence.

Even though darunavir/ritonavir (DRV/r) has high potency and a greater genetic barrier, there are few studies on the long-term effectiveness of DRV/r-based salvage therapy in people living with HIV (PLWH) in low and middle-income countries. This retrospective cohort study, from São Paulo, Brazil, included ART-experienced PLWH aged ≥18 years with virological failure (VF) who had started DRV/r plus an optimized background regimen (OBR) between 2008 and 2012. The proportion of patients with viral load (VL) 100,000 copies/mL and poor adherence were associated with VF. DRV/r plus an OBR showed high long-term virological suppression and immunological recovery. VL>100,000 copies/mL and poor adherence were associated with VF at 144 weeks.

BackgroundBrain imaging studies have shown altered amygdala activity during emotion processing in children and adolescents with oppositional defiant disorder (ODD) and conduct disorder (CD) compared to typically developing children and adolescents (TD). Here we aimed to assess whether aggression-related subtypes (reactive and proactive aggression) and callous-unemotional (CU) traits predicted variation in amygdala activity and skin conductance (SC) response during emotion processing.MethodsWe included 177 participants (n = 108 cases with disruptive behaviour and/or ODD/CD and n = 69 TD), aged 8–18 years, across nine sites in Europe, as part of the EU Aggressotype and MATRICS projects. All participants performed an emotional face-matching functional magnetic resonance imaging task.ResultsDifferences between cases and TD in affective processing, as well as specificity of activation patterns for aggression subtypes and CU traits, were assessed. Simultaneous SC recordings were acquired in a subsample (n = 63). Cases compared to TDs showed higher amygdala activity in response to negative faces (fearful and angry) v. shapes. Subtyping cases according to aggression-related subtypes did not significantly influence on amygdala activity; while stratification based on CU traits was more sensitive and revealed decreased amygdala activity in the high CU group. SC responses were significantly lower in cases and negatively correlated with CU traits, reactive and proactive aggression.ConclusionsOur results showed differences in amygdala activity and SC responses to emotional faces between cases with ODD/CD and TD, while CU traits moderate both central (amygdala) and peripheral (SC) responses. Our insights regarding subtypes and trait-specific aggression could be used for improved diagnostics and personalized treatment.

Streptococcus pneumoniae colonizes the nasopharynx of children and the elderly but also kills millions worldwide yearly. The secondary bile acid metabolite deoxycholic acid (DoC) affects the viability of human pathogens but also plays multiple roles in host physiology. We assessed in vitro the antimicrobial activity of DoC and investigated its potential to eradicate S. pneumoniae colonization using a model of human nasopharyngeal colonization and an in vivo mouse model of colonization. At a physiological concentration, DoC (0.5 mg/ml; 1.27 mM) killed all tested S. pneumoniae strains (n = 48) 2 h postinoculation. The model of nasopharyngeal colonization showed that DoC eradicated colonization by S. pneumoniae strains as soon as 10 min postexposure. The mechanism of action did not involve activation of autolysis, since the autolysis-defective double mutants ΔlytAΔlytC and ΔspxBΔlctO were as susceptible to DoC as was the wild type (WT). Oral streptococcal species (n = 20), however, were not susceptible to DoC (0.5 mg/ml). Unlike trimethoprim, whose spontaneous resistance frequency (srF) for TIGR4 or EF3030 was ≥1 × 10(−9), no spontaneous resistance was observed with DoC (srF, ≥1 × 10(–12)). Finally, the efficacy of DoC to eradicate S. pneumoniae colonization was assessed in vivo using a topical route via intranasal (i.n.) administration and as a prophylactic treatment. Mice challenged with S. pneumoniae EF3030 carried a median of 4.05 × 10(5) CFU/ml 4 days postinoculation compared to 6.67 × 10(4) CFU/ml for mice treated with DoC. Mice in the prophylactic group had an ∼99% reduction of the pneumococcal density (median, 2.61 × 10(3) CFU/ml). Thus, DoC, an endogenous human bile salt, has therapeutic potential against S. pneumoniae.

The pandemic of COVID-19 brought to the world an unprecedented challenge. This single center observational study aimed to evaluate the impact of staff preparedness by comparing the outcomes between two intensive care units (ICUs) from a hospital that had to expand ICU beds to deal with an incremented volume of critical patients. Patients consecutively admitted to these ICUs with suspected COVID-19, from March 1st until April 30th, 2020, were included. Both ICUs attended a similar population and had the same facilities, what differed was the staff: one previously well-established (ICU-1) and another recently assembled (ICU-2). 114 patients with severe respiratory syndrome were included. In-hospital mortality was 40%. Compared with patients in the well-established ICU-1, patients in the recently assembled ICU-2 were older (54 versus 61.5, p=0.045), received more antibiotics (93% versus 98%, p=0.001) and chloroquine/hydroxychloroquine 6% versus 30%, p=0.001), had a higher proportion of invasive mechanical ventilation (44% versus 52%, p=0.008) and had greater in-hospital mortality (30% versus 50%, p=0.017). The proportion of patients considered at high risk for death according to PSI was similar between the two ICU populations. Age ≥ 60 years (adjusted OR 2.33; 95% CI 1.02-5.31), need of invasive mechanical ventilation (adjusted OR 2.79; 95% CI 1.22-6.37), and ICU type (recently assembled) (adjusted OR 2.38; 95% CI 1.04-5.44) were independently associated with in-hospital mortality . This finding highlights the importance of developing support strategies to improve preparedness of staff recently assembled to deal with emergencies.

There has been considerable interest in applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) simultaneously for multimodal assessment of brain function. EEG–fNIRS can provide a comprehensive picture of brain electrical and hemodynamic function and has been applied across various fields of brain science. The development of wearable, mechanically and electrically integrated EEG–fNIRS technology is a critical next step in the evolution of this field. A suitable system design could significantly increase the data/image quality, the wearability, patient/subject comfort, and capability for long-term monitoring. Here, we present a concise, yet comprehensive, review of the progress that has been made toward achieving a wearable, integrated EEG–fNIRS system. Significant marks of progress include the development of both discrete component-based and microchip-based EEG–fNIRS technologies; modular systems; miniaturized, lightweight form factors; wireless capabilities; and shared analogue-to-digital converter (ADC) architecture between fNIRS and EEG data acquisitions. In describing the attributes, advantages, and disadvantages of current technologies, this review aims to provide a roadmap toward the next generation of wearable, integrated EEG–fNIRS systems.

Community-acquired pneumonia (CAP) is a common cause of hospitalization among people living with human immunodeficiency virus (PLWH), particularly those with severe immunosuppression. Pulmonary disease due to cryptococcosis is uncommonly reported and likely under-diagnosed. There is scarce information about cryptococcal antigen (CrAg) prevalence in PLWH with CAP. The objectives of this study were to identify among PLWH who were hospitalized with CAP: (i) the prevalence of serum CrAg positivity, (ii) the proportion with asymptomatic vs. symptomatic cryptococcosis; and (iii) the prevalence of serum CrAg positivity in CD4+ T-cell count 3. We performed a sub-analysis of a prospective cohort of hospitalized adults enrolled into a randomized clinical trial testing therapy for CAP. We included 202 participants who had serum CrAg testing performed. We found a 3.5% prevalence of serum CrAg-positivity overall, being higher (5.7%) in CD4+ T-cell count 3. Overall, asymptomatic and symptomatic cryptococcosis were present in 2.0% and 1.5%, respectively. This study identifies a target population for CrAg testing: PLWH hospitalized with diagnosis of CAP, particularly those with CD4+ T-cell count 3 where the number needed to test was 18 to detect 1 CrAg-positive person. This approach may facilitate the detection of asymptomatic cryptococcal infection and allow a timely diagnosis of symptomatic cryptococcal disease.

Culture-based methods for detecting Streptococcus pneumoniae in the nasopharynx lack sensitivity. In this study, we aimed to compare the performance of culture and molecular methods in detecting pneumococcus in the nasopharynx of healthy individuals and to evaluate the associations of age and colonization density with detection. Between 2010 and 2012, nasopharyngeal specimens were collected from healthy individuals living on Navajo Nation and White Mountain Apache Tribal lands in the United States. Pneumococci were detected by means of broth-enrichment culture and autolysin-encoding gene (lytA) quantitative polymerase chain reaction (qPCR). Among 982 persons evaluated (median age, 18.7 years; 47% male), 35% were culture-positive and an additional 27% were qPCR-positive. Agreement between culture and qPCR was 70.9% but was higher among children (age

Water contamination by pathogenic bacteria is a global public health problem. Contamination of surface water utilized to irrigate food products, or for human consumption, causes outbreaks of foodborne and waterborne disease. Of these, those caused by diarrheagenic Escherichia coli (DEC) strains present substantial morbidity and mortality. The aim of this study was, therefore, to investigate the microbiological quality of surface water and the presence of DEC strains in different water bodies. A total of 472 water samples were collected from irrigation canal, dam, river, and dike water bodies from January through December 2015 in Sinaloa, a State located in Northwestern Mexico. Our studies demonstrated that 47.0% (222/472) of samples contained thermotolerant coliforms above permissive levels whereas E. coli strains were isolated from 43.6% (206/472). Among these E. coli isolates, DEC strains were identified in 14% (29/206) of samples including in irrigation canal (26/29) and river water (3/29) collected from the northern (83%) and central area (17%). Isolated DEC strains were classified as enteroaggregative E. coli (EAEC) 34.4% (10/29), enteropathogenic E. coli (EPEC) 31.0% (9/29), diffuse adherent E. coli (DAEC) 27.5% (8/29), and enterotoxigenic E. coli (ETEC) 6.8% (2/29). Moreover, 90% of isolated DEC strains exhibited resistance to at least one commonly prescribed antibiotic in Mexico whereas 17% were multi-drug resistant. In conclusion, the presence of DEC strains in surface water represents a potential source for human infection, and thus routine monitoring of DEC in surface water and other indirect affected areas should be considered at northwestern Mexico.

The ubiquitin conjugating enzyme UBE2W catalyzes non-canonical ubiquitination on the N-termini of proteins, although its substrate repertoire remains unclear. To identify endogenous N-terminally-ubiquitinated substrates, we discover four monoclonal antibodies that selectively recognize tryptic peptides with an N-terminal diglycine remnant, corresponding to sites of N-terminal ubiquitination. Importantly, these antibodies do not recognize isopeptide-linked diglycine (ubiquitin) modifications on lysine. We solve the structure of one such antibody bound to a Gly-Gly-Met peptide to reveal the molecular basis for its selective recognition. We use these antibodies in conjunction with mass spectrometry proteomics to map N-terminal ubiquitination sites on endogenous substrates of UBE2W. These substrates include UCHL1 and UCHL5, where N-terminal ubiquitination distinctly alters deubiquitinase (DUB) activity. This work describes an antibody toolkit for enrichment and global profiling of endogenous N-terminal ubiquitination sites, while revealing functionally relevant substrates of UBE2W., UBE2W catalyzes the ubiquitination of protein N-termini but its substrate spectrum is largely unknown. Here, the authors discover mAbs selective for peptides derived from N-terminally ubiquitinated proteins, solve the structure of a peptide-bound mAb and apply the mAbs to map endogenous UBE2W substrates by proteomics.

Coronavirus disease 2019 (COVID-19) has been associated with an increased risk of venous and arterial thrombotic disease. Although pulmonary embolism has been the most common thrombotic complication, there have been recent reports of COVID-19-associated large-vessel ischemic stroke, acute upper- and lower-limb ischemia, as well as infarctions of the abdominal viscera, including renal, splenic, and small bowel infarctions. Here, we describe a case of splenic infarction (SI) associated with aortic thrombosis, which evolved despite the prophylactic use of low-molecular-weight heparin (LMWH), in a 60-year-old female patient with COVID-19. The patient was treated clinically with a therapeutic dose of LMWH, followed by warfarin, and eventually presented a favorable outcome. We also present a review of the literature regarding SI in patients with COVID-19.

BackgroundWe systematically assessed benefits and harms of the use of ivermectin (IVM) in COVID-19 patients.MethodsPublished and preprint randomized controlled trials (RCTs) assessing IVM effects on COVID-19 adult patients were searched until March 15, 2021 in five engines. Primary outcomes were all-cause mortality, length of stay (LOS), and adverse events (AE). Secondary outcomes included viral clearance and severe AEs. We evaluated risk of bias (RoB) using the Cochrane RoB 2·0 tool. Inverse variance random effect meta-analyses were performed with quality of evidence (QoE) evaluated using GRADE methodology. Subgroup analyses by severity of disease and RoB, and sensitivity analyses by time of follow-up were conducted.ResultsTen RCTs (n=1173) were included. Controls were standard of care [SOC] in five RCTs and placebo in five RCTs. RCTs sample size ranged from 24 to 398 patients, mean age from 26 to 56 years-old, and severity of COVID-19 disease was mild in 8 RCTs, moderate in one RCT, and mild and moderate in one RCT. IVM did not reduce all-cause mortality vs. controls (RR 0.37, 95%CI 0.12 to 1.13, very low QoE). IVM did not reduce LOS vs. controls (MD 0.72 days, 95%CI -0.86 to 2.29, very low QoE). AEs, severe AE and viral clearance were similar between IVM and controls (low QoE for these three outcomes). Subgroups by severity of COVID-19 or RoB were mostly consistent with main analyses; all-cause mortality in three RCTs at high RoB was reduced with IVM. Sensitivity analyses excluding RCTs with follow up ConclusionsIn comparison to SOC or placebo, IVM did not reduce all-cause mortality, length of stay or viral clearance in RCTs in COVID-19 patients with mostly mild disease. IVM did not have effect on AEs or SAEs. IVM is not a viable option to treat COVID-19 patients.

Disease should be diagnosed by using the Brighton Collaboration case definitions and cerebrospinal fluid IgM reactivity., Yellow fever (YF) vaccine can cause neurologic complications. We examined YF vaccine–associated neurologic disease reported from 3 tertiary referral centers in São Paulo, Brazil, during 2017–2018 and compared the performance of criteria established by the Yellow Fever Vaccine Working Group/Centers for Disease Control and Prevention and the Brighton Collaboration. Among 50 patients who met inclusion criteria, 32 had meningoencephalitis (14 with reactive YF IgM in cerebrospinal fluid), 2 died, and 1 may have transmitted infection to an infant through breast milk. Of 7 cases of autoimmune neurologic disease after YF vaccination, 2 were acute disseminated encephalomyelitis, 2 myelitis, and 3 Guillain-Barré syndrome. Neurologic disease can follow fractional vaccine doses, and novel potential vaccine-associated syndromes include autoimmune encephalitis, opsoclonus-myoclonus-ataxia syndrome, optic neuritis, and ataxia. Although the Brighton Collaboration criteria lack direct vaccine causal assessment, they are more inclusive than the Centers for Disease Control and Prevention criteria.

Streptococcus pneumoniae (Spn) colonizes the nasopharynx of children and the elderly but also kills millions worldwide yearly. The secondary bile acid metabolite, deoxycholic acid (DoC), affects the viability of human pathogens but also plays multiple roles in host physiology. We assessed in vitro the antimicrobial activity of DoC and investigated its potential to eradicate Spn colonization using an ex vivo model of human nasopharyngeal colonization and an in vivo mouse model of colonization. At a physiological concentration DoC (0.5 mg/ml; 1.27 mM) killed all tested Spn strains (N=48) two h post-inoculation. The ex-vivo model of nasopharyngeal colonization showed that DoC eradicated colonization by Spn strains as soon as 10 min post-exposure. The mechanism of action did not involve activation of autolysis since the autolysis-defective double mutants ΔlytAΔlytC and ΔspxBΔlctO were as susceptible to DoC as was the wild-type (WT). Oral streptococcal species (N=20), however, were not susceptible to DoC (0.5 mg/ml). Unlike trimethoprim, whose spontaneous resistance frequency (srF) for TIGR4 or EF3030 was ≥1×10−9, no spontaneous resistance was observed with DoC (srF≥1×10−12). Finally, the efficacy of DoC to eradicate Spn colonization was assessed in vivo using a topical route via intranasal (i.n.) administration and as a prophylactic treatment. Mice challenged with Spn EF3030 carried a median of 4.05×105 cfu/ml four days post-inoculation compared to 6.67×104 cfu/ml for mice treated with DoC. Mice in the prophylactic group had a ∼99% reduction of the pneumococcal density (median, 2.61 ×103 cfu/ml). Thus, DoC, an endogenous human bile salt, has therapeutic potential against Spn.

Significance: High-density diffuse optical tomography (HD-DOT) has been shown to approach the resolution and localization accuracy of blood oxygen level dependent-functional magnetic resonance imaging in the adult brain by exploiting densely spaced, overlapping samples of the probed tissue volume, but the technique has to date required large and cumbersome optical fiber arrays. Aim: To evaluate a wearable HD-DOT system that provides a comparable sampling density to large, fiber-based HD-DOT systems, but with vastly improved ergonomics. Approach: We investigated the performance of this system by replicating a series of classic visual stimulation paradigms, carried out in one highly sampled participant during 15 sessions to assess imaging performance and repeatability. Results: Hemodynamic response functions and cortical activation maps replicate the results obtained with larger fiber-based systems. Our results demonstrate focal activations in both oxyhemoglobin and deoxyhemoglobin with a high degree of repeatability observed across all sessions. A comparison with a simulated low-density array explicitly demonstrates the improvements in spatial localization, resolution, repeatability, and image contrast that can be obtained with this high-density technology. Conclusions: The system offers the possibility for minimally constrained, spatially resolved functional imaging of the human brain in almost any environment and holds particular promise in enabling neuroscience applications outside of the laboratory setting. It also opens up new opportunities to investigate populations unsuited to traditional imaging technologies.

Streptococcus pneumoniae grows in biofilms during both asymptomatic colonization and infection. Pneumococcal biofilms on abiotic surfaces exhibit delayed growth and lower biomass and lack the structures seen on epithelial cells or during nasopharyngeal carriage. We show here that adding hemoglobin to the medium activated unusually early and vigorous biofilm growth in multiple S. pneumoniae serotypes grown in batch cultures on abiotic surfaces. Human blood (but not serum, heme, or iron) also stimulated biofilms, and the pore-forming pneumolysin, ply, was required for this induction. S. pneumoniae transitioning from planktonic into sessile growth in the presence of hemoglobin displayed an extensive transcriptome remodeling within 1 and 2 h. Differentially expressed genes included those involved in the metabolism of carbohydrates, nucleotides, amino acid, and lipids. The switch into adherent states also influenced the expression of several regulatory systems, including the comCDE genes. Inactivation of comC resulted in 67% reduction in biofilm formation, while the deletion of comD or comE had limited or no effect, respectively. These observations suggest a novel route for CSP-1 signaling independent of the cognate ComDE two-component system. Biofilm induction and the associated transcriptome remodeling suggest hemoglobin serves as a signal for host colonization in pneumococcus.

There is a misconception that alpha-hemolysis observed on blood agar plate cultures of Streptococcus pneumoniae and other alpha-hemolytic streptococci is produced by a hemolysin or, alternatively, by lysis of erythrocytes caused by hydrogen peroxide. We noticed in the course of our investigations that wild-type S. pneumoniae strains and hemolysin (e.g., pneumolysin) knockout mutants produced the alpha-hemolytic halo on blood agar plates., Streptococcus pneumoniae and other streptococci produce a greenish halo on blood agar plates referred to as alpha-hemolysis. This phenotype is utilized by clinical microbiology laboratories to report culture findings of alpha-hemolytic streptococci, including S. pneumoniae, and other bacteria. The alpha-hemolysis halo on blood agar plates has been related to the hemolytic activity of pneumococcal pneumolysin (Ply) or, to a lesser extent, to lysis of erythrocytes by S. pneumoniae-produced hydrogen peroxide. We investigated the molecular basis of the alpha-hemolysis halo produced by S. pneumoniae. Wild-type strains TIGR4, D39, R6, and EF3030 and isogenic derivative Δply mutants produced similar alpha-hemolytic halos on blood agar plates, while cultures of hydrogen peroxide knockout ΔspxB ΔlctO mutants lacked this characteristic halo. Moreover, in the presence of catalase, the alpha-hemolysis halo was absent in cultures of the wild-type (wt) and Δply mutant strains. Spectroscopic studies demonstrated that culture supernatants of TIGR4 released hemoglobin-bound heme (heme-hemoglobin) from erythrocytes and oxidized oxy-hemoglobin to met-hemoglobin within 30 min of incubation. As expected, given Ply hemolytic activity and that hydrogen peroxide contributes to the release of Ply, TIGR4Δply and ΔspxB ΔlctO isogenic mutants had significantly decreased release of heme-hemoglobin from erythrocytes. However, TIGR4Δply that produces hydrogen peroxide oxidized oxy-hemoglobin to met-hemoglobin, whereas TIGR4ΔspxB ΔlctO failed to produce oxidation of oxy-hemoglobin. Studies conducted with all other wt strains and isogenic mutants resulted in similar findings. We demonstrated that the so-called alpha-hemolysis halo is caused by the oxidation of oxy-hemoglobin (Fe+2) to a non-oxygen-binding met-hemoglobin (Fe+3) by S. pneumoniae-produced hydrogen peroxide. IMPORTANCE There is a misconception that alpha-hemolysis observed on blood agar plate cultures of Streptococcus pneumoniae and other alpha-hemolytic streptococci is produced by a hemolysin or, alternatively, by lysis of erythrocytes caused by hydrogen peroxide. We noticed in the course of our investigations that wild-type S. pneumoniae strains and hemolysin (e.g., pneumolysin) knockout mutants produced the alpha-hemolytic halo on blood agar plates. In contrast, hydrogen peroxide-defective mutants prepared in four different strains lacked the characteristic alpha-hemolysis halo. We also demonstrated that wild-type strains and pneumolysin mutants oxidized oxy-hemoglobin to met-hemoglobin. Hydrogen peroxide knockout mutants, however, failed to oxidize oxy-hemoglobin. Therefore, the greenish halo formed on cultures of S. pneumoniae and other so-called alpha-hemolytic streptococci is caused by the oxidation of oxy-hemoglobin produced by hydrogen peroxide. Oxidation of oxy-hemoglobin to the nonbinding oxygen form, met-hemoglobin, might occur in the lungs during pneumococcal pneumonia.

The development of innovative antimicrobial materials is crucial in thwarting infectious diseases caused by microbes, as drug-resistant pathogens are increasing in both number and capacity to detoxify the antimicrobial drugs used today. An ideal antimicrobial material should inhibit a wide variety of bacteria in a short period of time, be less or not toxic to normal cells, and the fabrication or synthesis process should be cheap and easy. We report a one-step microwave-assisted hydrothermal synthesis of mixed composite CuxFeyOz (Fe2O3/Cu2O/CuO/CuFe2O) nanoparticles (NPs) as an excellent antimicrobial material. The 1 mg/mL CuxFeyOz NPs with the composition 36% CuFeO2, 28% Cu2O and 36% Fe2O3 have a general antimicrobial activity greater than 5 log reduction within 4 h against nine important human pathogenic bacteria (including drug-resistant bacteria as well as Gram-positive and Gram-negative strains). For example, they induced a &gt, 9 log reduction in Escherichia coli B viability after 15 min of incubation, and an ~8 log reduction in multidrug-resistant Klebsiella pneumoniae after 4 h incubation. Cytotoxicity tests against mouse fibroblast cells showed about 74% viability when exposed to 1 mg/mL CuxFeyOz NPs for 24 h, compared to the 20% viability for 1 mg/mL pure Cu2O NPs synthesized by the same method. These results show that the CuxFeyOz composite NPs are a highly efficient, low-toxicity and cheap antimicrobial material that has promising potential for applications in medical and food safety.

Cryptococcal meningitis remains a common cause of mortality in low- and middle-income countries, where amphotericin B deoxycholate (amphotericin) plus fluconazole is the most common treatment. Flucytosine is almost uniformly absent as is outcome data on flucytosine use in routine care. The main goal of this study was identified the cumulative mortality at 2, 4, and 10 weeks after hospital admission. We conducted a retrospective, observational cohort study among HIV-infected adults with cryptococcal meningitis receiving amphotericin plus flucytosine as induction therapy in Brazil. We assessed cumulative mortality at 2, 4, and 10 weeks and the cumulative proportion discontinuating amphotericin or flucytosine due to toxicity at 2 weeks. We performed multiple logistic regression to identify variables associated with in-hospital mortality. In total, 77 individuals (n = 66 men) were included with median baseline CD4 of 29 (IQR, 9–68) cells/mcL. Twenty (26%) had at least one concurrent neurological disease diagnosed. Sixty (78%) patients received at least 14 days of amphotericin plus flucytosine. Cumulative mortality was 5% (4/77) at 2 weeks, 8% (6/77) at 4 weeks, and 19% (15/77) at 10 weeks. Cumulative proportion of patients that discontinuated amphotericin or flucytosine due to toxicity was 20% (16/77) at 2 weeks. In addition, in-hospital mortality was associated with receiving ≤ 10 days of induction therapy (odds ratio = 4.5, 95% CI 1.2–17.1, P = 0.028) or positive cerebrospinal fluid fungal culture after 2 weeks (odds ratio = 3.8, 95% CI 1.1–13.5, P = 0.035). In this “real-world” study, amphotericin plus flucytosine shows low early mortality of patients with HIV-associated cryptococcal meningitis. Early discontinuation due to adverse events was moderate. More effective and safe antifungals are needed in order to improve the outcome of cryptococcal meningitis.

Streptococcus pneumoniae (the pneumococcus) is a significant global pathogen. Accurate identification and serotyping are vital. In contrast with World Health Organization recommendations based on culture methods, we demonstrate that pneumococcal identification and serotyping with molecular methods are affected by sample type. Results from oropharyngeal samples from adults were often inaccurate. This is particularly important for assessment of vaccine impact using carriage studies, particularly in low- and middle-income countries where there are significant barriers for disease surveillance., Streptococcus pneumoniae (the pneumococcus) carriage is commonly used to measure effects of pneumococcal vaccines. Based on findings from culture-based studies, the World Health Organization recommends both nasopharyngeal (NP) and oropharyngeal (OP) sampling for detecting adult carriage. Given evidence of potential confounding by other streptococci, we evaluated molecular methods for pneumococcal identification and serotyping from 250 OP samples collected from adults in Fiji, using paired NP samples for comparison. Samples were screened using lytA quantitative PCR (qPCR), as well as pneumococcal identification and serotyping conducted by DNA microarray. A subset of OP samples were characterized by latex sweep agglutination and multiplex PCR. Alternate qPCR assays (piaB and bguR) for pneumococcal identification were evaluated. The lytA qPCR was less specific and had poor positive predictive value (PPV) in OP samples (88% and 26%, respectively) compared with NP samples (95% and 64%, respectively). Using additional targets piaB and/or bguR improved qPCR specificity in OP, although the PPV (42 to 53%) was still poor. Using microarray, we found that 102/107 (95%) of OP samples contained nonpneumococcal streptococci with partial or divergent complements of pneumococcal capsule genes. We explored 91 colonies isolated from 11 OP samples using various techniques, including multiplex PCR, latex agglutination, and microarray. We found that nonpneumococcal streptococci contribute to false positives in pneumococcal serotyping and may also contribute to spurious identification by qPCR. Our results highlight that molecular approaches should include multiple loci to minimize false-positive results when testing OP samples. Regardless of method, pneumococcal identification and serotyping results from OP samples should be interpreted with caution. IMPORTANCE Streptococcus pneumoniae (the pneumococcus) is a significant global pathogen. Accurate identification and serotyping are vital. In contrast with World Health Organization recommendations based on culture methods, we demonstrate that pneumococcal identification and serotyping with molecular methods are affected by sample type. Results from oropharyngeal samples from adults were often inaccurate. This is particularly important for assessment of vaccine impact using carriage studies, particularly in low- and middle-income countries where there are significant barriers for disease surveillance.

Streptococcus pneumoniae (Spn) and other streptococci produce a greenish halo on blood agar plates referred to as α-hemolysis. This phenotype is utilized by clinical microbiology laboratories to report culture findings of α-hemolytic streptococci, including Spn, and other bacteria. The α-hemolysis halo on blood agar plates has been related to the hemolytic activity of pneumococcal pneumolysin (Ply), or to a lesser extent, to lysis of erythrocytes by Spn-produced hydrogen peroxide. We investigated the molecular basis of the α-hemolysis halo produced by Spn. Wild-type strains TIGR4, D39, R6, and EF3030, and isogenic derivative Δply mutants, produced a similar α-hemolytic halo on blood agar plates while cultures of hydrogen peroxide knockout ΔspxB/ΔlctO mutants lacked this characteristic halo. Spectroscopic studies demonstrated that culture supernatants of TIGR4 released hemoglobin-bound heme (heme-hemoglobin) from erythrocytes and oxidized oxy-hemoglobin to met-hemoglobin within 30 min of incubation. As expected, given Ply hemolytic activity, and that hydrogen peroxide contributes to the release of Ply, TIGR4 isogenic mutants Δply and ΔspxB/ΔlctO had a significantly decreased release of heme-hemoglobin from erythrocytes. However, TIGR4Δply that produces hydrogen peroxide oxidized oxy-hemoglobin to met-hemoglobin, whereas TIGR4ΔspxB/ΔlctO failed to produce oxidation of oxy-hemoglobin. We demonstrated that the so-called α-hemolysis halo is caused by the oxidation oxy-hemoglobin (Fe+2) to a non-oxygen binding met-hemoglobin (Fe+3) by Spn-produced hydrogen peroxide. Since Spn colonizes the human lung, oxidation of oxy-hemoglobin might have important implications for pathogenesis.ImportanceThere is a misconception that α-hemolysis observed on blood agar plates cultures of Streptococcus pneumoniae (Spn), and other α-hemolytic streptococci is produced by a hemolysin, or alternatively, by lysis of erythrocytes caused by hydrogen peroxide. We noticed in the course of our investigations that wild-type Spn strains and hemolysin (e.g., pneumolysin) knockout mutants, produced the α-hemolytic halo on blood agar plates. In contrast, hydrogen peroxide defective mutants prepared in four different strains lacked the characteristic α-hemolysis halo. We also demonstrated that wild-type strains and pneumolysin mutants oxidized oxy-hemoglobin to met-hemoglobin. Hydrogen peroxide knockout mutants, however, failed to oxidize oxy-hemoglobin. Therefore, the greenish halo formed on cultures of Spn and other so-called α-hemolytic streptococci is caused by the oxidation of oxy-hemoglobin produced by hydrogen peroxide. Oxidation of oxy-hemoglobin to the non-binding oxygen form, met-hemoglobin, might occur in the lungs during pneumococcal pneumonia.

Increased nasopharyngeal pneumococcal (Streptococcus pneumoniae) colonization density has been associated with invasive pneumococcal disease, but factors that increase pneumococcal density are poorly understood. We evaluated pneumococcal densities in nasopharyngeal samples from asymptomatic young children from Peru and their association with subsequent acute respiratory illness (ARI). Total pneumococcal densities (encompassing all present serotypes) during asymptomatic periods were significantly higher when a respiratory virus was detected versus when no virus was detected (p

Cerebral toxoplasmosis is the most common cause of focal brain lesion in people living with HIV (PLWH) and usually causes multifocal encephalitis with little or no meningeal involvement. Classically, only subtle cerebrospinal fluid (CSF) abnormalities are described. There are no prior case reports in the literature on eosinophilic meningitis associated with cerebral toxoplasmosis in PLWH. We report on an HIV-positive man from Brazil who presented to the emergency department with headache, nausea, vomiting, and hemiparesis. He had a T-CD4+ lymphocyte count of 145 cells/mm3, and antiretroviral failure was identified. Brain computed tomography showed a contrast-enhancing lesion with mild mass effect and trimethoprim–sulfamethoxazole and dexamethasone were started. Examination of CSF showed 194 cells/mm3 (74% eosinophils, 18% lymphocytes, 4% monocytes, and 2% neutrophils), protein = 83 mg/dL, and glucose = 49 mg/dL. Detection of Toxoplasma gondii on CSF by polymerase chain reaction confirmed the diagnosis of cerebral toxoplasmosis. An exhaustive laboratorial investigation excluded other possible etiologies. After 14 days, the patient showed complete resolution of neurological and CSF alterations and substantial improvement in the brain lesion and was discharged home. We suggest that eosinophilic meningitis should be included in the spectrum of manifestations of HIV-related cerebral toxoplasmosis, especially in countries with high prevalence of toxoplasmosis in the general population.

Clostridium perfringens strains cause a wide variety of human and animal disease, including gas gangrene or myonecrosis. Production of toxins required for myonecrosis, PFO and CPA, is regulated by the C. perfringens Agr-like (CpAL) system via the VirSR two-component system. Myonecrosis begins at the site of infection from where bacteria migrate deep into the host tissue likely using a previously described gliding motility phenotype. We therefore assessed whether gliding motility was under the control of the CpAL/VirSR regulon. The migration rate of myonecrosis-causing C. perfringens strain 13 (S13) was investigated during a 96 h period, including an adaptation phase with bacterial migration (∼1.4 mm/day) followed by a gliding phase allowing bacteria faster migration (∼8.6 mm/day). Gliding required both an intact CpAL system, and signaling through VirSR. Mutants lacking ΔagrB, or ΔvirR, were impaired for onward gliding while a complemented strain S13ΔagrB/pTS1303 had the gliding phenotype restored. Gene expression studies revealed upregulated transcription of pili genes (pilA1, pilA2 and pilT) whose encoded proteins were previously found to be required for gliding motility and CpAL/VirSR-regulated pfoA and cpa toxin genes. Compared to S13, transcription of cpa and pfoA significantly decreased in S13ΔagrB, or S13ΔvirR, strains but not that of pili genes. Further experiments demonstrated that mutants S13ΔpfoA and S13Δcpa migrated at the same rate as S13 wt. We demonstrated that CpAL/VirSR regulates C. perfringens gliding motility and that gliding bacteria have an increased transcription of toxin genes involved in myonecrosis.

Resumen Introduccion El bloqueo del plano del musculo erector (ESP) es una tecnica novedosa para el tratamiento del dolor agudo y cronico. Su lugar y mecanismo de accion todavia no han sido explicados. Objetivos Determinar el mecanismo de accion del anestesico local en el bloqueo ESP a traves de la inyeccion del azul de metileno, describiendo su distribucion desde la cara anterior del torax. Hallar o determinar un paso o canal por el cual el anestesico atraviesa las estructuras musculares y oseas de posterior a anterior. Materiales y metodos Se utilizaron 4 columnas de cadaveres frescos criopreservados. Se realizaron 9 bloqueos ESP ecoguiados en diferentes regiones de los especimenes con 20 ml de azul de metileno al 0,01% por bloqueo. Se observo la distribucion del colorante desde la cara anterior de torax, midiendo la cantidad de espacios intercostales tenidos, antes y despues de la extraccion de la pleura parietal, y se registraron las estructuras en que se constato tintura. Resultados En todos los bloqueos ESP se encontro colorante en el espacio paravertebral, los espacios intercostales y en algunos casos en la cadena prevertebral. Los bloqueos tuvieron un promedio de 4,6 espacios intercostales tenidos, con un maximo de 7 y un minimo de 3. La intensidad del colorante fue mayor del lado de la inyeccion, dorsal a la columna, que el hallado en la parte ventral por debajo de la pleura. No se logro constatar un mecanismo claro por el que el colorante difundiera hacia el la zona anterior. Conclusiones Por los datos recogidos en este trabajo se puede deducir que el bloqueo ESP tiene un mecanismo de accion anestesico similar a los bloqueos paravertebrales. El sitio por el cual el anestesico atravesaria desde el plano posterior de la columna a la region anterior del torax no fue aclarado y deberia ser investigado en futuros trabajos.

Introduction The erector spinae plane (ESP) block is a novel technique for the treatment of acute and chronic pain. Its mechanism and site of action has not yet been explained properly. Objectives In order to explain the mechanism of action of the ESP block, injections were performed with methylene blue to simulate the local anaesthetics and to determine its distribution from the anterior side of the thorax. To find an aperture or channel through which the local anaesthetic passes from posterior to anterior through the muscular and bone structures. Materials and methods Four spinal columns of fresh cryopreserved corpses were used. A total of 9 ultrasound-guided ESP blocks were performed in different regions of the specimens using 20 ml of 0.01% methylene blue per block. The distribution of the dye was observed from the anterior side of the thorax, measuring the amount of intercostal spaces stained, before and after the removal of the parietal pleura, and the structures in which the stain was found were recorded. Results In all blocks of the ESP, dye was found in the paravertebral space, intercostal spaces, and in some cases in the prevertebral chain. The blocks had a mean of 4.6 intercostal spaces stained, with a maximum of 7 and a minimum of 3. The intensity of the dye was greater on the side of the injection, dorsal to the column, than that found in the ventral part below of the pleura. It was not possible to verify a clear channel through which the dye diffuses towards the previous zone. Conclusions From the data collected in this study, it can be deduced that the blockade of the ESP has a mechanism of anaesthetic action similar to paravertebral blocks. The site from which the anaesthetic would cross from the posterior plane of the spine to the anterior region of the thorax was not clear, and should be investigated in future works.