Characterization of Decellularized Human Pericardium for Tissue Engineering and Regenerative Medicine Applications / Caracterização do Pericárdio Humano Descelularizado para Engenharia de Tecidos e Aplicações de Medicina Regenerativa

Abstract Background: Pericardium tissue allograft can be used for surgical repair in several procedures. One of the tissue engineering strategies is the process of decellularization. This process decreases immunogenic response, but it may modify the natural extracellular matrix composition and behavior. Objective: The aim of this study was to evaluate the effectiveness of cell removal, maintenance of extracellular matrix properties and mechanical integrity of decellularized human pericardium using a low concentration solution of sodium dodecyl sulfate. Methods: Decellularization was performed with sodium dodecyl sulfate and ethylenediaminetetraacetic acid. Histological analysis, DNA quantification, evaluation of glycosaminoglycans and collagen were performed. Biomechanical assay was performed using tensile test to compare the decellularization effects on tissue properties of tensile strength, elongation and elastic modulus. P < 0.05 was considered significant. Results: There was reduction in visible nuclei present in pericardium tissue after decellularization, but it retained collagen and elastin bundles similar to fresh pericardium. The DNA contents of the decellularized pericardium were significantly reduced to less than 511.23 ± 120.4 ng per mg of dry weight (p < 0.001). The biomechanical assay showed no significant difference for fresh or decellularized tissue. Conclusion: The decellularization process reduces cell content as well as extracellular matrix components without changing its biomechanical properties.

Resumo Fundameto: O enxerto de pericárdio pode ser usado em muitos procedimentos de correção cirúrgica. Uma das estratégias da engenharia tecidual é o processo de descelularização. No entanto, embora esse processo diminua a resposta imunogênica, a descelularização pode modificar tanto o comportamento como a composição da matriz extracelular natural. Objetivos: Avaliar a eficácia da descelularização usando baixa concentração de dodecil sulfato de sódio na remoção celular, na manutenção das propriedades da matriz extracelular e na integridade mecânica do pericárdio humano descelularizado. Métodos: A descelularização foi realizada com dodecil sulfato de sódio e ácido etilenodiamino tetra-acético. Foi realizada análise histológica, quantificação de DNA, e avaliação de glicosaminoglicanos e colágeno. O estudo biomecânico foi conduzido pelo teste de tração para comparar os efeitos da descelularização sobre as propriedades teciduais de resistência à tração, alongamento e módulo de elasticidade. Foi considerado um valor de p < 0,05 como estatisticamente significativo. Resultados: Observou-se uma redução na quantidade de núcleos presentes no pericárdio após a descelularização, apesar de manter quantidades similares de feixes de elastina e de colágeno. As concentrações de DNA do pericárdio descelularizado foram significativamente reduzidas para menos que 511,23 ± 120,4 ng por mg de peso seco (p < 0,001). O teste biomecânico não apontou diferenças entre os tecidos fresco e descelularizado. Conclusão: A descelularização reduziu a concentração de células bem como os componentes da matriz extracelular sem afetar suas propriedades biomecânicas.

Risk factors for mortality in patients with ventilator-associated pneumonia caused by carbapenem-resistant Enterobacteriaceae

Abstract Background: The ideal therapeutic option for ventilator associated pneumonia caused by carbapenem-resistant Enterobacteriaceae is not defined. The aim of this study was to assess mortality-associated risk factors in patients with VAP by CRE and determine the outcome of several treatment options. Methods: This was a retrospective study performed in two tertiary hospitals involving patients with VAP caused by CRE between January 2010 and August 2014. The outcomes were mortality within 30 days of VAP diagnosis and overall mortality during hospital admission. Risk factors for mortality were assessed by comparing variables of survivors and non-survivors. Results: One hundred and twelve patients with CRE-VAP were included, 73 (65%) male, median age 56 years. The 30-day mortality was 57.1% and the overall hospital mortality was 67%. In the binary logistic regression analysis, only age >50 years was independently associated to increased mortality. Polymyxin was the most used drug (47.5%), followed by tigecycline (29.2%) and aminoglycosides (2.4%). Combined therapy with two active drugs was used by 17 patients (20.8%). No therapeutic option was independently associated to survival. However, combined therapy with two active drugs was superior to the therapy with a single active drug when inappropriate therapy was the comparator (p = 0.044). The addition of carbapenem was not associated with increased survival. Conclusion: The best therapeutic option for VAP by CRE is still not completely defined, but the therapy with at least two active drugs was superior in this study.

Tipagem molecular e resistência aos antimicrobianos em isolados de Escherichia coli de frangos de corte e de tratadores na região metropolitana de Curitiba, Paraná / Molecular typing and antimicrobial resistance in isolates of Escherichia coli from poultry and farmers in the metropolitan region of Curitiba, Paraná

Este estudo verificou o perfil de resistência aos antimicrobianos entre isolados de Escherichia coli de frangos de corte de criação intensiva e de subsistência e dos respectivos tratadores e a similaridade genotípica entre isolados de E.coli de frangos de corte de criação intensiva e isolados de E. coli de tratadores de frangos de criação intensiva pela técnica de Eletroforese em Gel de Campo Pulsado (PFGE). 60 amostras de fezes de frangos de criação intensiva, 60 de frangos de corte de criação de subsistência (caipira) e 20 amostras dos tratadores de frangos de criação intensiva e 20 de tratadores de frangos de criação de subsistência. E. coli foram isoladas, identificadas e submetidas ao teste de suscetibilidade a 12 antimicrobianos. Pela PFGE foram analisados 24 isolados de E. coli de frangos de corte de criação intensiva e oito de tratadores. Em isolados E. coli de frangos de criação intensiva a resistência para a ampicilina foi de 100%, cefotaxima 43%, ceftriaxona 48%, ácido nalidíxico 62%, enrofloxacina 23%, ciprofloxacina 23%, tetraciclina 83% e 45% para trimetoprim-sulfametoxazol. Nos isolados de frangos de criação de subsistência foi de 20%, 0%, 0%, 5%, 2%, 4%, 33% e 8%, respectivamente...

This study examined the profile of antimicrobial resistance among isolates of Escherichia coli from poultry intensive farming and free-range systems and their farmers. For technique of Gel Electrophoresis Pulsed Field (PFGE) examined the similarity between isolates from poultry intensive farming and their farmers. From 60 samples of poultry feces from intensive farming systems, 60 of free-range extensive systems and 20 of farmers of each segment, the E. coli was isolated and submitted to the test of susceptability to 12 antimicrobials. 24 isolates of E. coli of poultry from intensive farming systems and eight E. coli isolates from farmers poultry intensive farming were analyzed via technique of PFGE. In intensive farming systems poultry, 100% resistence to ampicillin was verified, 43% to cefotaxime, 48% to ceftriaxone, 62% to nalidixic acid, 23% to enrofloxacin, 23% to ciprofloxacin, 83% to tetracycline and 45% to trimetroprim-sulfametoxazol. In the strains of free-range extensive systems, resistance was 20%, 0%, 0%, 5%, 2%, 4%, 33% and 8%, respectively...

A simple mathematical model to determine the ideal empirical antibiotic therapy for bacteremic patients

BACKGROUND: Local epidemiological data are always helpful when choosing the best antibiotic regimen, but it is more complex than it seems as it may require the analysis of multiple combinations. The aim of this study was to demonstrate a simplified mathematical calculation to determine the most appropriate antibiotic combination in a scenario where monotherapy is doomed to failure. METHODS: The susceptibility pattern of 11 antibiotics from 216 positive blood cultures from January 2012 to January 2013 was analyzed based on local policy. The length of hospitalization before bacteremia and the unit (ward or intensive care unit) were the analyzed variables. Bacteremia was classified as early, intermediate or late. The antibiotics were combined according to the combination model presented herein. RESULTS: A total of 55 possible mathematical associations were found combining 2 by 2, 165 associations with 3 by 3 and 330 combinations with 4 by 4. In the intensive care unit, monotherapy never reached 80% of susceptibility. In the ward, only carbapenems covered more than 90% of early bacteremia. Only three drugs combined reached a susceptibility rate higher than 90% anywhere in the hospital. Several regimens using four drugs combined reached 100% of susceptibility. CONCLUSIONS: Association of three drugs is necessary for adequate coverage of empirical treatment of bacteremia in both the intensive care unit and the ward. .

Risk factors for KPC-producing Klebsiella pneumoniae bacteremia

The molecular epidemiology of carbapenemase-producing Klebsiella pneumoniae (KPC) has been largely investigated, but limited clinical information is available. A case-control study was performed to evaluate the risk factors for KPC bacteremia in hospitalized patients. Cases were patients with KPC bacteremia and controls were patients with non-KPC bacteremia. A total of 85 patients were included, 18 (21.2%) were KPC, and 67 (78.8%) were non-KPC (40 [59.7%] of them were extended-spectrum beta-lactamase producers). All KPC isolates were type 2 producers. These isolates belong to five distinct clones. Multivariate analysis showed that age (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02 - 1.11; p = 0.004), presence of mechanical ventilation (OR, 11.1; 95% CI, 1.92 - 63.3; p = 0.007) and fluoroquinolone exposure during hospitalization (OR, 28.9; 95% CI, 1.85 - 454.6; p = 0.02) were independent risk factors for KPC in patients with K. pneumoniae bacteremia. Factors associated with severity of illness, such as age and mechanical ventilation, seem to be the main risks factors for KPC. Fluoroquinolones use might be a risk factor for KPC bacteremia. Further investigations on risk factors for KPC are warranted.

Risk factors for pan-resistant Pseudomonas aeruginosa bacteremia and the adequacy of antibiotic therapy

INTRODUCTION: The aim of this study was to determine risk factors for acquiring carbapenemresistant Pseudomonas aeruginosa bacteremia (CR-PA) and factors associated with in-hospital mortality. METHODS: Seventy-seven cases of bacteremia caused by P. aeruginosa were evaluated in a hospital with high incidence of CR-PA. Clinical and laboratorial factors, and previous use of antibiotics were also evaluated. In one analysis, CR-PA and carbapenem-susceptible P. aeruginosa (CS-PA) bacteremia were compared. A second analysis compared patients who died with survivors. RESULTS: Among 77 P. aeruginosa bacteremia, 29 were caused by CR-PA. Admission to the intensive care unit, higher number of total leukocytes, and previous use of carbapenem were statistically associated with CR-PA. In the multivariate analysis, only previous use of carbapenem (including ertapenem) turned out to be a risk factor for CR-PA (p = 0.014). The 30-day mortality of patients with P. aeruginosa bloodstream infection was 44.8% for CS-PA and 54.2% for patients with CR-PA (p = 0.288). Chronic renal failure, admission to the intensive care unit, mechanical ventilation, and central venous catheter were risk factors for mortality. Incorrect treatment increased mortality of patients with bacteremia caused by CS-PA, but not for CR-SA. The odd ratio of mortality associated with incorrect therapy in patients with CS-PA was 3.30 (1.01-10.82; p = 0.043). The mortality of patients with bacteremia caused by CR-PA was unexpectedly similar regardless of antimicrobial treatment adequacy. CONCLUSION: Appropriate treatment for CS-PA bacteremia initiated within the first 24 hours was associated with lower mortality, but this cannot be extrapolated for CR-PA.

Central venous catheter-related bloodstream infection and Cryptococcus neoformans

This is the first case reported of central venous catheter-related fungemia due to C. neoformans. A patient with chronic renal failure developed a fungemia during the treatment of a dialysis-associated bacteremia. Cryptococcus neoformans grew in the catheter tip and blood culture. We addressed questions about this catheter-related fungemia.