In vitro and in vivo antimicrobial activity of sodium colistimethate and amikacin-loaded nanostructured lipid carriers (NLC).

Sodium colistimethate (SCM) and amikacin (AMK) are among the few antibiotics effective against resistant P. aeruginosa, K. pneumoniae and A. baumannii; however, their toxicity severely limits their use. Enclosing antibiotics into nanostructured lipid carriers (NLC) might decrease drug toxicity and improve antibiotic disposition. In this work, SCM or AMK was loaded into different NLC formulations, through high pressure homogenization, and their in vitro and in vivo effectiveness was analyzed. The encapsulation process did not reduce drug effectiveness since in vitro SCM-NLC and AMK-NLC drug activity was equal to that of the free drugs. As cryoprotectant, trehalose showed better properties than dextran. Instead, positive chitosan coating was discarded due to its limited cost-efficiency. Finally, the in vivo study in acute pneumonia model revealed that intraperitoneal administration was superior to the intramuscular route and confirmed that (-) SCM-NLC with trehalose, was the most suitable formulation against an extensively drug-resistant A. baumannii strain.

European Space Agency experiments on thermodiffusion of fluid mixtures in space.

This paper describes the European Space Agency (ESA) experiments devoted to study thermodiffusion of fluid mixtures in microgravity environment, where sedimentation and convection do not affect the mass flow induced by the Soret effect. First, the experiments performed on binary mixtures in the IVIDIL and GRADFLEX experiments are described. Then, further experiments on ternary mixtures and complex fluids performed in DCMIX and planned to be performed in the context of the NEUF-DIX project are presented. Finally, multi-component mixtures studied in the SCCO project are detailed.

Impact of Staphylococcus aureus phenotype and genotype on the clinical characteristics and outcome of infective endocarditis. A multicentre, longitudinal, prospective, observational study.

OBJECTIVE: We aimed to evaluate the impact of Staphylococcus aureus phenotype (vancomycin MIC) and genotype (agr group, clonal complex CC) on the prognosis and clinical characteristics of infective endocarditis (IE). METHODS: We performed a multicentre, longitudinal, prospective, observational study (June 2013 to March 2016) in 15 Spanish hospitals. Two hundred and thirteen consecutive adults (≥18 years) with a definite diagnosis of S. aureus IE were included. Primary outcome was death during hospital stay. Main secondary end points were persistent bacteraemia, sepsis/septic shock, peripheral embolism and osteoarticular involvement. RESULTS: Overall in-hospital mortality was 37% (n = 72). Independent risk factors for death were age-adjusted Charlson co-morbidity index (OR 1.20; 95% CI 1.08-1.34), congestive heart failure (OR 3.60; 95% CI 1.72-7.50), symptomatic central nervous system complication (OR 3.17; 95% CI 1.41-7.11) and severe sepsis/septic shock (OR 4.41; 95% CI 2.18-8.96). In the subgroup of methicillin-susceptible S. aureus IE (n = 173), independent risk factors for death were the age-adjusted Charlson co-morbidity index (OR 1.17; 95% CI 1.03-1.31), congestive heart failure (OR 3.39; 95% CI 1.51-7.64), new conduction abnormality (OR 4.42; 95% CI 1.27-15.34), severe sepsis/septic shock (OR 5.76; 95% CI 2.57-12.89) and agr group III (OR 0.27; 0.10-0.75). Vancomycin MIC ≥1.5 mg/L was not independently associated with death during hospital nor was it related to secondary end points. No other genotype variables were independently associated with in-hospital death. CONCLUSIONS: This is the first prospective study to assess the impact of S. aureus phenotype and genotype. Phenotype and genotype provided no additional predictive value beyond conventional clinical characteristics. No evidence was found to justify therapeutic decisions based on vancomycin MIC for either methicillin-resistant or methicillin-susceptible S. aureus.

Management of multidrug resistant Gram-negative bacilli infections in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations.

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant (MDR) Gram-negative bacilli (GNB), as they are frequently exposed to antibiotics and the healthcare setting, and are regulary subject to invasive procedures. Nevertheless, no recommendations concerning prevention and treatment are available. A panel of experts revised the available evidence; this document summarizes their recommendations: (1) it is important to characterize the isolate's phenotypic and genotypic resistance profile; (2) overall, donor colonization should not constitute a contraindication to transplantation, although active infected kidney and lung grafts should be avoided; (3) recipient colonization is associated with an increased risk of infection, but is not a contraindication to transplantation; (4) different surgical prophylaxis regimens are not recommended for patients colonized with carbapenem-resistant GNB; (5) timely detection of carriers, contact isolation precautions, hand hygiene compliance and antibiotic control policies are important preventive measures; (6) there is not sufficient data to recommend intestinal decolonization; (7) colonized lung transplant recipients could benefit from prophylactic inhaled antibiotics, specially for Pseudomonas aeruginosa; (8) colonized SOT recipients should receive an empirical treatment which includes active antibiotics, and directed therapy should be adjusted according to susceptibility study results and the severity of the infection.

Blood and tissue distribution of posaconazole in a rat model of invasive pulmonary aspergillosis.

Posaconazole is the recommended prophylactic agent in patients at high risk of invasive fungal infection, since adequate drug levels seem to be reached in target sites despite the relatively low levels detected in blood. The objective of this study is to obtain pharmacokinetic (PK) information associated to blood and tissue distribution of posaconazole in an animal model of invasive pulmonary aspergillosis. The PK parameters in lung samples were systematically higher than in serum. After multiple-dose administration of posaconazole, a significant accumulation of the drug was evident in lung tissue. The PK behavior of posaconazole in this particular experimental model is similar to that observed in humans. Thus, we believe this model could be a valid tool to evaluate posaconazole exposure-response relationship.

Epidemiology and Immediate Indirect Effects of Respiratory Viruses in Lung Transplant Recipients: A 5-Year Prospective Study.

The epidemiology of respiratory viruses (RVs) in lung transplant recipients (LTRs) and the relationship of RVs to lung function, acute rejection (AR) and opportunistic infections in these patients are not well known. We performed a prospective cohort study (2009-2014) by collecting nasopharyngeal swabs (NPSs) from asymptomatic LTRs during seasonal changes and from LTRs with upper respiratory tract infectious disease (URTID), lower respiratory tract infectious disease (LRTID) and AR. NPSs were analyzed by multiplex polymerase chain reaction. Overall, 1094 NPSs were collected from 98 patients with a 23.6% positivity rate and mean follow-up of 3.4 years (interquartile range 2.5-4.0 years). Approximately half of URTIDs (47 of 97, 48.5%) and tracheobronchitis cases (22 of 56, 39.3%) were caused by picornavirus, whereas pneumonia was caused mainly by paramyxovirus (four of nine, 44.4%) and influenza (two of nine, 22.2%). In LTRs with LRTID, lung function changed significantly at 1 mo (p = 0.03) and 3 mo (p = 0.04). In a nested case-control analysis, AR was associated with RVs (hazard ratio [HR] 6.54), Pseudomonas aeruginosa was associated with LRTID (HR 8.54), and cytomegalovirus (CMV) replication or disease was associated with URTID (HR 2.53) in the previous 3 mo. There was no association between RVs and Aspergillus spp. colonization or infection (HR 0.71). In conclusion, we documented a high incidence of RV infections in LTRs. LRTID produced significant lung function abnormalities. Associations were observed between AR and RVs, between P. aeruginosa colonization or infection and LRTID, and between CMV replication or disease and URTID.

Management of cytomegalovirus infection in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations.

Cytomegalovirus (CMV) infection remains a major complication of solid organ transplantation. Because of management of CMV is variable among transplant centers, in 2011 the Spanish Transplantation Infection Study Group (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) developed consensus guidelines for the prevention and treatment of CMV infection in solid organ transplant recipients. Since then, new publications have clarified or questioned the aspects covered in the previous document. For that reason, a panel of experts revised the evidence on CMV management, including immunological monitoring, diagnostics, prevention, vaccines, indirect effects, treatment, drug resistance, immunotherapy, investigational drugs, and pediatric issues. This document summarizes the recommendations.

Epidemiology of invasive respiratory disease caused by emerging non-Aspergillus molds in lung transplant recipients.

OBJECTIVES: Our aim was to assess the impact of positive cultures for non-Aspergillus molds on the risk of progression to invasive fungal infection (IFI), and the effect of prophylactic nebulized liposomal amphotericin B (n-LAB) on these pathogens. METHODS: This was an observational study (2003-2013) including lung transplant recipients (LTR) receiving lifetime n-LAB prophylaxis, in whom non-Aspergillus molds were isolated on respiratory culture before and after transplantation (minimum 1-year follow-up). RESULTS: We studied 412 patients, with a mean postoperative follow-up of 2.56 years (interquartile range 1.01-4.65). Pre- and post-transplantation respiratory samples were frequently positive for non-Aspergillus molds (11.9% and 16.9% of LTR respectively). Post transplantation, 10 (2.42%) patients developed non-Aspergillus mold infection (4 Scedosporium species, 4 Purpureocillium species, 1 Penicillium species, and 1 Scopulariopsis species); 5 (1.21%) had IFI, with 60% IFI-related mortality. Non-Aspergillus molds with intrinsic amphotericin B (AB) resistance were more commonly isolated in bronchoscopy samples than AB-variably sensitive or AB-sensitive molds (54.5% vs. 25%, P = 0.04) and were associated with a higher risk of infection (56.3% vs. 1.3%%, P < 0.01). CONCLUSIONS: In LTR undergoing n-LAB prophylaxis, pre- and post-transplantation isolation of non-Aspergillus molds is frequent, but IFI incidence (1.21%) is low. Purpureocillium is an emerging mold. AB-resistant non-Aspergillus species were found more often in bronchoscopy samples and were associated with a higher risk of infection.

Influenza vaccination during the first 6 months after solid organ transplantation is efficacious and safe.

Preventing influenza infection early after transplantation is essential, given the disease's high mortality. A multicentre prospective cohort study in adult solid organ transplant recipients (SOTR) receiving the influenza vaccine during four consecutive influenza seasons (2009-2013) was performed to assess the immunogenicity and safety of influenza vaccination in SOTR before and 6 months after transplantation. A total of 798 SOTR, 130 of them vaccinated within 6 months of transplantation and 668 of them vaccinated more than 6 months since transplantation. Seroprotection was similar in both groups: 73.1% vs. 76.5% for A/(H1N1)pdm (p 0.49), 67.5% vs. 74.1% for A/H3N2 (p 0.17) and 84.2% vs. 85.2% for influenza B (p 0.80), respectively. Geometric mean titres after vaccination did not differ among groups: 117.32 (95% confidence interval (CI) 81.52, 168.83) vs. 87.43 (95% CI 72.87, 104.91) for A/(H1N1)pdm, 120.45 (95% CI 82.17, 176.57) vs. 97.86 (95% CI 81.34, 117.44) for A/H3N2 and 143.32 (95% CI 103.46, 198.53) vs. 145.54 (95% CI 122.35, 174.24) for influenza B, respectively. After adjusting for confounding factors, time since transplantation was not associated with response to vaccination. No cases of rejection or severe adverse events were detected in patients vaccinated within the first 6 months after transplantation. In conclusion, influenza vaccination within the first 6 months after transplantation is as safe and immunogenic as vaccination thereafter. Thus, administration of the influenza vaccine can be recommended as soon as 1 month after transplantation.

Multidrug-resistant bacteria in solid organ transplant recipients.

Bacteria are the leading cause of infections after solid organ transplantation. In recent years, a progressive growth in the incidence of multidrug-resistant (MDR) and extensively-drug-reistant (XDR) strains has been observed. While methicillin-resistant Staphylococcus aureus (MRSA) infection is declining in non-transplant and SOT patients worldwide, vancomycin-resistant enterococci, MDR/XDR Enterobacteriaceae and MDR/XDR non-fermenters are progressively growing as a cause of infection in solid organ transplant (SOT) patients and represent a global threat. Some SOT patients develop recurrent infections, related to anatomical defects in many cases, which are difficult to treat and predispose patients to the acquisition of MDR pathogens. As the antibiotics active against MDR bacteria have several limitations for their use, which include less clinical experience, higher incidence of adverse effects and less knowledge of the pharmacokinetics of the drug, and, in most cases, are only available for parenteral administration, it is mandatory to know the main characteristics of these drugs to safely treat SOT patients with MDR bacterial infections. Nonetheless, preventive measures are the cornerstone of controlling the spread of these pathogens. Thus, applying the Center for Disease Control and Prevention's and the European Society of Clinical Microbiology and Infectious Diseases's recommended antibiotic policies and strategies to control the transmission of MDR strains in the hospital setting is essential for the management of SOT patients.

Invasive fungal infections in solid organ transplant recipients.

Solid organ transplant (SOT) recipients have a significant risk of invasive fungal diseases (IFD) caused mainly by Candida spp. and Aspergillus spp. Candida spp. is the most frequent agent of IFD in the transplant recipient. The absence of clinical trials and the epidemiological differences in IFD in different transplant programmes mean that there are no definitive recommendations for the diagnosis, treatment and prevention of IFD in SOT, so most of the evidence must be based on clinical experience.

Daptomycin is safe and effective for the treatment of gram-positive cocci infections in solid organ transplantation.

INTRODUCTION: Infections caused by resistant gram-positive cocci (GPC), especially to glycopeptides, are difficult to treat in solid organ transplant (SOT) recipients as a result of lower effectiveness and high rates of renal impairment. The aim of this study was to evaluate the use of daptomycin in this population. METHODS: Over a 2-year period (March 2008-2010) in 9 Spanish centers, we enrolled all consecutive recipients who received daptomycin to treat GPC infection. The study included 43 patients, mainly liver and kidney transplant recipients. RESULTS: The most frequent infections were catheter-related bacteremia caused by coagulase-negative staphylococci (23.2%), skin infection caused by Staphylococcus aureus (11.5%), and intra-abdominal abscess caused by Enterococcus faecium (20.9%). The daily daptomycin dose was 6 mg/kg in 32 patients (74.4%). On day 7 of daptomycin treatment, median estimated area under the curve was 1251 µg/mL/h. At the end of follow-up, analytical parameters were similar to the values at the start of therapy. No changes were observed in tacrolimus levels. No patient required discontinuation of daptomycin because of adverse effects. Clinical success at treatment completion was achieved in 37 (86%) patients. Three patients died while on treatment with daptomycin. CONCLUSION: In summary, daptomycin was a safe and useful treatment for GPC infection in SOT recipients.

Prevention strategies for cytomegalovirus disease and long-term outcomes in the high-risk transplant patient (D+/R-): experience from the RESITRA-REIPI cohort.

BACKGROUND: Cytomegalovirus (CMV)-negative recipients of a graft from a CMV-positive donor (D+/R-) are at high risk of CMV disease. Current preventive strategies include universal prophylaxis (UP) and preemptive therapy (PT). However, the best strategy to prevent CMV disease and achieve better long-term outcomes remains a matter of debate. METHODS: We analyzed the incidence of CMV disease and long-term outcomes including graft dysfunction and patient mortality at 5 years after transplantation with both preventive strategies. High-risk (D+/R-) kidney and liver transplant recipients from the RESITRA cohort were included. RESULTS: Of 2410 kidney or liver transplant patients, 195 (8.3%) were D+/R-. The final cohort included 58 liver and 102 kidney recipients. UP was given in 92 patients and 68 received PT; 10.9% and 36.8% developed CMV disease, respectively (P < 0.01). The independent risk factors for CMV disease were PT strategy (hazard ratio [HR], 3.30; 95% confidence interval [CI], 1.6-6.9), kidney transplantation (HR, 3.8; 95% CI, 1.4-9.9), and cyclosporine immunosuppression (HR, 2.4; 95% CI, 1.2-4.7). PT strategy was also a risk factor for CMV disease in both liver transplantation (HR, 11.0; 95% CI, 1.2-98.7) and kidney transplantation (HR, 2.7; 95% CI, 1.3-6.0), independently. The development of CMV replication during the first 2 years after transplantation was a risk factor for graft dysfunction at 5 years after transplantation (odds ratio, 3.4; 95% CI, 1.3-9.0). Nevertheless, no significant differences were seen in either graft dysfunction or mortality between the 2 strategies. CONCLUSIONS: The study supports the benefit of the UP strategy to prevent CMV disease in D+/R- liver or kidney transplant patients. The development of CMV replication during the first 2 years after transplantation was associated with graft dysfunction at 5 years after transplantation.

Unusual forms of subacute invasive pulmonary aspergillosis in patients with solid tumors.

OBJECTIVES: Aspergillus spp. can cause acute invasive disease in severely immunocompromised patients. Nonetheless, there are few reports of solid tumors complicated with subacute invasive pulmonary aspergillosis (subacute IPA). METHODS: Retrospective observational cohort study, performed in patients with primary lung cancer or secondary lung metastasis complicated with subacute IPA in three referral hospitals. RESULTS: From 2008 to 2011, 14 episodes of subacute IPA were diagnosed, including 11 (78.6%) probable and 3 proven (21.4%). Nine patients (64.3%) had primary lung cancer. Thirteen patients (92.9%) had more than one local or systemic predisposing factor for subacute IPA. No patient had previous fungal colonization. Aspergillus spp. was isolated in 6 specimens of bronchoalveolar lavage, 6 sputum, 2 biopsies, and 1 percutaneous lung puncture. At the time Aspergillus spp. was isolated, the most common radiologic findings on chest computed tomography (CT) were cavitary masses, and development or expansion of cavitation in existing masses or nodules (10/14, 71.4%). On CT follow-up, most patients (8/12, 66.7%) had new cavity formation or expansion of one or more existing cavities. All patients were treated with azoles and two underwent surgery. Ten (71.4%) patients died after Aspergillus spp. was detected (median time 73 days, IQR 33-243): 2 (20%) deaths were subacute IPA-attributable and 6 (60%) were related. CONCLUSIONS: Primary lung cancer and secondary lung metastasis seem to be triggering factors for Aspergillus spp. implantation, and predispose to subacute IPA. Once localized in the damaged lung, the mold can grow and cause or expand cavities. In lung cancer patients, Aspergillus spp. detection is associated with a very poor prognosis.

Immunogenicity of pandemic influenza A H1N1/2009 adjuvanted vaccine in pediatric solid organ transplant recipients.

The aim of this study was to assess the immunogenicity of a vaccine against this virus in a prospective cohort of transplanted pediatric patients without previous influenza infection who received one dose of MF59®-adjuvanted pandemic H1N1/2009 vaccine. Seventeen patients who were being regularly followed up at the Outpatient Clinic of the Children's Transplant Unit (liver and kidney transplantation) in Hospital Universitari Vall d'Hebron (Barcelona) were included. Seroconversion was demonstrated in 15 of 17 (88.2%) vaccinated children. There were no rejection episodes or major adverse events. The MF59(®) -adjuvanted pandemic H1N1/2009 vaccine was safe and elicited an adequate response.

Liver lipocalin 2 expression in severely obese women with non alcoholic fatty liver disease.

BACKGROUND: Lipocalin 2 (LCN2) has been related to obesity, insulin resistance and metabolic disturbance. However, its relation with non alcoholic fatty liver disease (NAFLD) has hardly been studied. METHODS: We examined LCN2 circulating levels and its protein and gene expression in liver from women with severe obesity and NAFLD. We analyzed the liver histology of 59 white severely obese women (BMI ≥40 Kg/m²): 15 subjects presented normal liver histology or non-significant liver disease (NL), 18 simple steatosis (SS) and 26 non alcoholic steatohepatitis (NASH). We determined the anthropometric and metabolic features of the women. LCN2 levels were determined by an ELISA and liver mRNA expression by real time RT-PCR. We also studied LCN2 expression in HepG2 liver cells under various inflammatory stimuli. RESULTS: Liver LCN2 protein and gene expression were higher in NAFLD than in obese with NL. Liver LCN2 gene expression correlated with SS (r=0.351, p=0.016), and its protein expression correlated with NASH (r=0.705, p=0.003). LCN2 expression was detected in HepG2 cells after the administration of TNFα, IL6, resistin or adiponectin. LCN2 expression was induced by TNFα, IL6 and resistin. CONCLUSIONS: Liver LCN2 is related to NAFLD in severely obese women. Up-regulation of LCN2 expression is detected in HepG2 cells after exposure to TNFα, IL6 and resistin. These results suggest that LCN2 expression is induced under liver harmful conditions.

Reduced incidence of pneumonia in influenza-vaccinated solid organ transplant recipients with influenza disease.

Whether influenza vaccination influences the severity of illness in cases of clinical failure in solid organ transplant (SOT) recipients receiving influenza vaccine has not been extensively studied. Our goal was to evaluate the frequency of influenza vaccination among SOT recipients with influenza disease and its impact on the illness severity during the 2010-2011 season. Adult SOT recipients with confirmed influenza infection were included from December 2010 to April 2011. Follow-up data were recorded and antibody titres were determined using a microneutralization assay. Sixty-four SOT recipients were included in the study, ten (15.6%) with severe disease, requiring admission to intensive care units, of whom four (6.3%) died. In all, 34 (53.1%) received the 2010-2011 seasonal influenza vaccine and 32 (50.0%) received the 2009-H1N1 pandemic vaccine, and none had detectable antibodies against influenza at the time of diagnosis of influenza infection. Twenty-three (67.6%) of the patients that received the vaccine required hospital admission and presented less dyspnoea (10, 29.4% versus 14 (50.0%), p 0.09) and pneumonia (8, 23.8% versus 15, 50.0%, p 0.03, relative risk 0.3, 95% CI 0.1-0.9) than unvaccinated patients, with relative risk reductions of 60% and 70%, respectively. Although influenza vaccination confers protection on SOT recipients against developing influenza pneumonia, the rate of clinical failure is still high. New strategies to improve influenza immunization are needed for this group of patients.

Influenza A H1N1/2009 infection in pediatric solid organ transplant recipients.

AIM AND METHOD: The aim of this study was to describe the clinical characteristics and outcome of pandemic influenza A H1N1/2009 (pH1N1) infection, in a retrospective cohort of pediatric patients with kidney and/or liver transplant and confirmed pH1N1 infection from June to December 2009, diagnosed in 2 Spanish teaching hospitals. RESULTS: Forty-nine patients were included. Pneumonia was diagnosed in 4 patients (8.2%), and 3 of them required respiratory support. There were no related deaths. CONCLUSION: Antiviral treatment within 48 h was associated with a lower likelihood of pneumonia (0/38, 0%) than treatment started after 48 h (4/11, 36.3%) (P < 0.01).

Therapy with m-TOR inhibitors decreases the response to the pandemic influenza A H1N1 vaccine in solid organ transplant recipients.

Concern has been raised regarding the response to vaccination in solid organ transplant recipients (SOTR) undergoing immunosuppressant regimens and the possibility of rejection related to the immune response associated with pandemic influenza H1N1-2009 vaccination. The goal of this study was to assess the immunogenicity, efficacy and safety of the pandemic vaccine in SOTR. We performed a multicenter prospective study in SOTR receiving the pandemic vaccine. Immunological response was determined in serum 5 weeks after vaccination by microneutralization assays, and immunoglobulins were measured by ELISA. Three hundred and forty-six SOTR were included. Preexisting seroprotection was detected in 13.6% of cases and rates of seroconversion and seroprotection after vaccination were 73.1% and 82.9%, respectively. Patients with baseline antibody titers had better geometric mean titers (GMT)-post after pandemic vaccination (339.4 vs. 121.4, p < 0.001). Younger age, liver disease and m-TOR inhibitor therapy were independently associated with lower seroprotection and GMT-post. There were no major adverse effects or rejection episodes. Pandemic vaccine was safe in SOTR and elicited an adequate response, although lower than in healthy individuals. This is the first study describing a decreased response after vaccination in patients receiving mTOR inhibitors who presented lower seroprotection rates and lower GMT-post.