Flagellin delays spontaneous human neutrophil apoptosis

Neutrophils are short-lived cells that rapidly undergo apoptosis. However, their survival can be regulated by signals from the environment. Flagellin, the primary component of the bacterial flagella, is known to induce neutrophil activation. In this study we examined the ability of flagellin to modulate neutrophil apoptosis. Neutrophils cultured for 12 and 24 h in the presence of flagellin from Salmonella thyphimurim at concentrations found in pathological situations underwent a marked prevention of apoptosis. In contrast, Helicobacter pylori flagellin did not affect neutrophil survival, suggesting that Salmonella flagellin exerts the antiapoptotic effect by interacting with TLR5. The delaying in apoptosis mediated by Salmonella flagellin was coupled to higher expression levels of the antiapoptotic protein Mcl-1 and lower levels of activated caspase-3. Analysis of the signaling pathways indicated that Salmonella flagellin induced the activation of the p38 and ERK1/2 MAPK pathways as well as the PI3K/Akt pathway. Furthermore, it also stimulated IBα degradation and the phosphorylation of the p65 subunit, suggesting that Salmonella flagellin also triggers NF-B activation. Moreover, the pharmacological inhibition of ERK1/2 pathway and NF-B activation partially prevented the antiapoptotic effects exerted by flagellin. Finally, the apoptotic delaying effect exerted by flagellin was also evidenced when neutrophils were cultured with whole heat-killed S. thyphimurim. Both a wild-type and an aflagellate mutant S. thyphimurim strain promoted neutrophil survival; however, when cultured in low bacteria/neutrophil ratios, the flagellate bacteria showed a higher capacity to inhibit neutrophil apoptosis, although both strains showed a similar ability to induce neutrophil activation. Taken together, our results indicate that flagellin delays neutrophil apoptosis by a mechanism partially dependent on the activation of ERK1/2 MAPK and NF-B. The ability of flagellin to delay neutrophil apoptosis could contribute to perpetuate the inflammation during infections with flagellated bacteria.Facultad de Ciencias Exacta

Flagellin delays spontaneous human neutrophil apoptosis

Neutrophils are short-lived cells that rapidly undergo apoptosis. However, their survival can be regulated by signals from the environment. Flagellin, the primary component of the bacterial flagella, is known to induce neutrophil activation. In this study we examined the ability of flagellin to modulate neutrophil apoptosis. Neutrophils cultured for 12 and 24 h in the presence of flagellin from Salmonella thyphimurim at concentrations found in pathological situations underwent a marked prevention of apoptosis. In contrast, Helicobacter pylori flagellin did not affect neutrophil survival, suggesting that Salmonella flagellin exerts the antiapoptotic effect by interacting with TLR5. The delaying in apoptosis mediated by Salmonella flagellin was coupled to higher expression levels of the antiapoptotic protein Mcl-1 and lower levels of activated caspase-3. Analysis of the signaling pathways indicated that Salmonella flagellin induced the activation of the p38 and ERK1/2 MAPK pathways as well as the PI3K/Akt pathway. Furthermore, it also stimulated IBα degradation and the phosphorylation of the p65 subunit, suggesting that Salmonella flagellin also triggers NF-B activation. Moreover, the pharmacological inhibition of ERK1/2 pathway and NF-B activation partially prevented the antiapoptotic effects exerted by flagellin. Finally, the apoptotic delaying effect exerted by flagellin was also evidenced when neutrophils were cultured with whole heat-killed S. thyphimurim. Both a wild-type and an aflagellate mutant S. thyphimurim strain promoted neutrophil survival; however, when cultured in low bacteria/neutrophil ratios, the flagellate bacteria showed a higher capacity to inhibit neutrophil apoptosis, although both strains showed a similar ability to induce neutrophil activation. Taken together, our results indicate that flagellin delays neutrophil apoptosis by a mechanism partially dependent on the activation of ERK1/2 MAPK and NF-B. The ability of flagellin to delay neutrophil apoptosis could contribute to perpetuate the inflammation during infections with flagellated bacteria.Facultad de Ciencias Exacta

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

TNF-alfa y modulación del fenómeno apoptótico en neutrófilos humanos

El presente trabajo examinó la capacidad del TNF-a. de modular la apoptosis de neutrófilos humanos. Observamos que los neutrófilos cultivados sólo con TNF-a.sufren un pequeño pero significativo incremento en sus porcentajes de apoptosis. Llamativamente. observamos además que aquellos neutrófilos pretratados con TNF-a por 1-2 minutos a 37°C y expuestos luego a una variedad de agentes tales como IgG inmovilizada (IgGi), eritrocitos recubiertos por anticuerpos lgG (lgG-E), eritrocitos tratados con complemento (EC), zimosán (Z), ácido forbol miristico (PMA), suero activado por zimosán (ZAS), N-formilmetionil-leucil-fenilalanina (fMLP), Escherichia coli, y factor estimulador de la formación de colonias para granulocitos y macrófagos (GM-CSF) por 3 horas a 37°C, experimentaron un marcado incremento en sus porcentajes de apoptosis. Resultados similares fueron obtenidos en neutrófilos pretratados con TNF-a por 30 minutos, 1, 3 y 18 horas. Las concentraciones a las cuales el TNF-a. medió este efecto promotor de la apoptosis se hallaron comprendidas entre 1 y 100 nglml. En contraste con las observaciones realizadas en neutrófilos pretratados con TNF-a, no observamos promoción alguna de la apoptosis cuando el TNF-a fue añadido a neutrófilos previamente activados por agonistas convencionales. Las experiencias realizadas a fin de determinar el mecanismo responsable de la promoción de apoptosis por TNF-a mostraron que el mismo no es dependiente de la generación de intermediarios reactivos del oxígeno (IRO) ní de la participación del sistema Fas/FasL. Por el contrario, pareciera involucrar la activación de las vias intrínseca y extrinseca del mecanismo apoptótico y asociarse a una dramática disminución en la expresión de la proteina anti-apoptótica Mol-1. Nuestros resultados sugieren que el TNF-a juega un papel critico en el control de la sobrevida del neutrófilo en virtud de su capacidad de inducir la puesta en marcha del proceso apoptótioo, proceso que es 'gatillado' por una amplia variedad de agonistas convencionales.This work examined the ability of TNF-a to modulate human neutrophil apoptosis. Neutrophils cultured with TNF-a alone undergo a low but significant increase in the number of apoptotic cells. More interestingly, when neutrophils were pretreated with TNFa. for 1-2 min at 37°C, and then were exposed to a variety of agents such as immobilized lgG (ilgG), IgG-coated erythrocytes (lgG-E), complement-treated erythrocytes (CE), zymosan (Z), phorbol 12-myristate 13-acetate (PMA),zymosan-activated serum (ZAS), N-formylmethionyl-leucyl-phenylalanine (fMLP), Escherichia coli, and granulocytemacrophage colony-stimulating factor (GM-CSF) for 3 h at 37°C, a marked stimulation of apoptosis was observed. Similar results were obtained in neutrophils pretreated with TNFa for 30 min, 1 h, 3 h, and 18 h. Bose-dependent studies showed that TNF-a enhances neutrophil apoptosis at oonoentrations ranging from 1 to 100 ng/ml. ln contrast to the observations made in neutrophils pretreated with TNF-a, there was no stimulation of apoptosis when TNF-a was added to neutrophils previously activated by conventional agonists. Experiments performed to establish the mechanism through which TNF-a promotes neutrophil apoptosis showed that: a) it was not dependent on the generation of reactive oxygen interrnediates (ROI) nor the participation of the Fas/FasL system, b) it appears to involve the activation of both, the extrinsic and ¡ntn'nsicpathway of apoptosis, and c) it was associated to a dramatic down regulation of the expression of anti-apoptotic protein Mol-1. Our results suggest that TNF-a plays a critical role in the control of neutrophil survival by virtue of its ability to induce an apoptotic death program which could be tiiggered by a variety of conventional agonists.Fil:Salamone, Gabriela V.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Glioblastoma cells potentiate the induction of the Th1-like profile in phosphoantigen-stimulated γδ T lymphocytes

Purpose: γδ T lymphocytes are non-conventional T cells that participate in protective immunity and tumor surveillance. In healthy humans, the main subset of circulating γδ T cells express the TCRVγ9Vδ2. This subset responds to non-peptide prenyl-pyrophosphate antigens such as (E)-4-hydroxy-3-methyl-but-enyl pyrophosphate (HMBPP). This unique feature of Vγ9Vδ2 T cells makes them a candidate for anti-tumor immunotherapy. In this study, we investigated the response of HMBPP-activated Vγ9Vδ2 T lymphocytes to glioblastoma multiforme (GBM) cells.Methods: Human purified γδ T cells were stimulated with HMBPP (1 µM) and incubated with GBM cells (U251, U373 and primary GBM cultures) or their conditioned medium. After overnight incubation, expression of CD69 and perforin was evaluated by flow cytometry and cytokines production by ELISA. As well, we performed a meta-analysis of transcriptomic data obtained from The Cancer Genome Atlas.Results: HMBPP-stimulated γδ T cells cultured with GBM or its conditioned medium increased CD69, intracellular perforin, IFN-γ, and TNF-α production. A meta-analysis of transcriptomic data showed that GBM patients display better overall survival when mRNA TRGV9, the Vγ9 chain-encoding gene, was expressed in high levels. Moreover, its expression was higher in low-grade GBM compared to GBM. Interestingly, there was an association between γδ T cell infiltrates and TNF-α expression in the tumor microenvironment.Conclusion: GBM cells enhanced Th1-like profile differentiation in phosphoantigen-stimulated γδ T cells. Our results reinforce data that have demonstrated the implication of Vγ9Vδ2 T cells in the control of GBM, and this knowledge is fundamental to the development of immunotherapeutic protocols to treat GBM based on γδ T cells.Fil: Rosso, David Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Rosato, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Iturrizaga, Juan. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: González, Nazareno. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Shiromizu, Carolina Maiumi. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Keitelman, Irene Angélica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Coronel, Juan V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Gómez, Fernando Daniel. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Amaral, María Marta. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rabadan, Alejandra T.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Salamone, Gabriela Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología; ArgentinaFil: Jancic, Carolina Cristina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Surgical site infection after gastrointestinal surgery in children : an international, multicentre, prospective cohort study

Introduction Surgical site infection (SSI) is one of the most common healthcare-associated infections (HAIs). However, there is a lack of data available about SSI in children worldwide, especially from low-income and middle-income countries. This study aimed to estimate the incidence of SSI in children and associations between SSI and morbidity across human development settings. Methods A multicentre, international, prospective, validated cohort study of children aged under 16 years undergoing clean-contaminated, contaminated or dirty gastrointestinal surgery. Any hospital in the world providing paediatric surgery was eligible to contribute data between January and July 2016. The primary outcome was the incidence of SSI by 30 days. Relationships between explanatory variables and SSI were examined using multilevel logistic regression. Countries were stratified into high development, middle development and low development groups using the United Nations Human Development Index (HDI). Results Of 1159 children across 181 hospitals in 51 countries, 523 (45 center dot 1%) children were from high HDI, 397 (34 center dot 2%) from middle HDI and 239 (20 center dot 6%) from low HDI countries. The 30-day SSI rate was 6.3% (33/523) in high HDI, 12 center dot 8% (51/397) in middle HDI and 24 center dot 7% (59/239) in low HDI countries. SSI was associated with higher incidence of 30-day mortality, intervention, organ-space infection and other HAIs, with the highest rates seen in low HDI countries. Median length of stay in patients who had an SSI was longer (7.0 days), compared with 3.0 days in patients who did not have an SSI. Use of laparoscopy was associated with significantly lower SSI rates, even after accounting for HDI. Conclusion The odds of SSI in children is nearly four times greater in low HDI compared with high HDI countries. Policies to reduce SSI should be prioritised as part of the wider global agenda.Peer reviewe

Safety of primary anastomosis following emergency left sided colorectal resection: an international, multi-centre prospective audit.

This is the peer reviewed version of the following article: group, T. E. S. o. C. c. (2018). "Safety of primary anastomosis following emergency left sided colorectal resection: an international, multi-centre prospective audit." Colorectal Disease 20(S6): 47-57., which has been published in final form at https://doi.org/10.1111/codi.1437. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsINTRODUCTION: Some evidence suggests that primary anastomosis following left sided colorectal resection in the emergency setting may be safe in selected patients, and confer favourable outcomes to permanent enterostomy. The aim of this study was to compare the major postoperative complication rate in patients undergoing end stoma vs primary anastomosis following emergency left sided colorectal resection. METHODS: A pre-planned analysis of the European Society of Coloproctology 2017 audit. Adult patients (> 16 years) who underwent emergency (unplanned, within 24 h of hospital admission) left sided colonic or rectal resection were included. The primary endpoint was the 30-day major complication rate (Clavien-Dindo grade 3 to 5). RESULTS: From 591 patients, 455 (77%) received an end stoma, 103 a primary anastomosis (17%) and 33 primary anastomosis with defunctioning stoma (6%). In multivariable models, anastomosis was associated with a similar major complication rate to end stoma (adjusted odds ratio for end stoma 1.52, 95%CI 0.83-2.79, P = 0.173). Although a defunctioning stoma was not associated with reduced anastomotic leak (12% defunctioned [4/33] vs 13% not defunctioned [13/97], adjusted odds ratio 2.19, 95%CI 0.43-11.02, P = 0.343), it was associated with less severe complications (75% [3/4] with defunctioning stoma, 86.7% anastomosis only [13/15]), a lower mortality rate (0% [0/4] vs 20% [3/15]), and fewer reoperations (50% [2/4] vs 73% [11/15]) when a leak did occur. CONCLUSIONS: Primary anastomosis in selected patients appears safe after left sided emergency colorectal resection. A defunctioning stoma might mitigate against risk of subsequent complications