Niche Differentiation in the Composition, Predicted Function, and Co-occurrence Networks in Bacterial Communities Associated With Antarctic Vascular Plants.

Climate change directly affecting the Antarctic Peninsula has been reported to induce the successful colonization of ice-free lands by two Antarctic vascular plants (Deschampsia antarctica and Colobanthus quitensis). While studies have revealed the importance of microbiota for plant growth and stress tolerance in temperate climates, the role that plant-associated microbes play in the colonization of ice-free lands remains unknown. Consequently, we used high-throughput DNA sequence analyses to explore the composition, predicted functions, and interactive networks of plant-associated microbial communities among the rhizosphere, endosphere, and phyllosphere niches of D. antarctica and C. quitensis. Here we report a greater number of operational taxonomic units (OTUs), diversity, and richness in the microbial communities from the rhizosphere, relative to endosphere and phyllosphere. While taxonomic assignments showed greater relative abundances of Proteobacteria, Bacteroidetes, and Actinobacteria in plant niches, principal coordinate analysis revealed differences among the bacterial communities from the other compartments examined. More importantly, however, our results showed that most of OTUs were exclusively found in each plant niche. Major predicted functional groups of these microbiota were attributed to heterotrophy, aerobic heterotrophy, fermentation, and nitrate reduction, independent of plant niches or plant species. Co-occurrences network analyses identified 5 (e.g., Microbacteriaceae, Pseudomonaceae, Lactobacillaceae, and Corynebacteriaceae), 23 (e.g., Chitinophagaceae and Sphingomonadaceae) and 7 (e.g., Rhodospirillaceae) putative keystone taxa present in endosphere, phyllosphere, and rhizosphere, respectively. Our results revealed niche differentiation in Antarctic vascular plants, highlighting some putative microbial indicators and keystone taxa in each niche. However, more studies are required to determine the pivotal role that these microbes play in the successful colonization of ice-free lands by Antarctic plants.

Chlorhexidine-silver sulfadiazine-impregnated venous catheters are efficient even at subclavian sites without tracheostomy.

BACKGROUND: Chlorhexidine-silver sulfadiazine (CHSS)-impregnated catheters have been found to decrease the risk of catheter-related bloodstream infection (CRBSI) and central venous catheter (CVC)-related costs. However, there are no published data about cost-effectiveness of the use of CHSS-impregnated catheters in subclavian venous access without the presence of tracheostomy (thus, with a very low risk of CRBSI). That was the objective of this study. METHODS: This was a retrospective study of patients admitted to a mixed intensive care unit who underwent placement of subclavian venous catheters without the presence of tracheostomy. RESULTS: Patients with standard catheters (n = 747) showed a higher CRBSI incidence density (0.95 vs 0/1,000 catheter-days; P = .02) and higher CVC-related cost per day ($3.78 ± $7.43 vs $3.31 ± $2.72; P < .001) than patients with a CHSS-impregnated catheter (n = 879). Exact logistic regression analysis showed that catheter duration (P = .02) and the type of catheter used (P = .01) were associated with the risk of CRBSI. Kaplan-Meier method showed that CHSS-impregnated catheters were associated with more prolonged CRBSI-free time than standard catheters (log-rank = 9.76; P = .002). Poisson regression analysis showed that CHSS-impregnated catheters were associated with a lower central venous catheter-related cost per day than standard catheters (odds ratio, 0.87; 95% confidence interval, 0.001-0.903; P < .001). CONCLUSIONS: The use of CHSS-impregnated catheters is an effective and efficient measure for the prevention of CRBSI even at subclavian venous access sites without the presence of tracheostomy.

Chlorhexidine-silver sulfadiazine- or rifampicin-miconazole-impregnated venous catheters decrease the risk of catheter-related bloodstream infection similarly.

BACKGROUND: The objective of this study was to compare the incidence of catheter-related bloodstream infection (CRBSI) with the use of second-generation chlorhexidine-silver sulfadiazine (CHSS)-impregnated catheters, rifampicin-miconazole (RM)-impregnated catheters, and standard catheters. METHODS: Retrospective study of patients admitted to an intensive care unit who received CHSS, RM, or standard catheters in femoral venous access. RESULTS: We diagnosed 18 CRBSIs in 245 patients with standard catheters in 2,061 days, zero CRBSI in 169 patients with CHSS-impregnated catheters in 1,489 days, and zero CRBSI in 227 patients with RM-impregnated catheters in 2,009 days. Patients with standard catheters compared with CHSS- and RM-impregnated catheters showed a higher rate of CRBSI (7.3%, 0%, and 0%, respectively; P < .001) and higher incidence density of CRBSI (8.7, 0, and 0 per 1,000 catheter days, respectively; P < .001). We found in the exact Poisson regression that standard catheters were associated with a higher CRBSI incidence than CHSS-impregnated catheters (P < .001) and RM-impregnated catheters (P < .001), controlling for catheter duration. We found in survival analysis that standard catheters were associated with a lower CRBSI-free time than CHSS-impregnated catheters (P < .001) and RM-impregnated catheters (P < .001). CONCLUSION: We found that CHSS- and RM-impregnated catheters decreased similarly the risk of CRBSI.

Efficiency of chlorhexidine-silver sulfadiazine-impregnated venous catheters at subclavian sites.

BACKGROUND: Cost-effectiveness analyses show that chlorhexidine-silver sulfadiazine (CHSS)-impregnated catheters reduce catheter-related bloodstream infection (CRBSI) and central venous catheter (CVC)-related costs. However, no studies have reported the efficiency of CHSS-impregnated catheters for venous access when the risk of CRBSI is low; for example, at the subclavian site. This study determined the cost of a CVC, diagnosis of CRBSI, and antimicrobial agents to treat CRBSI; we did not consider the cost of increased hospital stay. METHODS: This retrospective study included patients admitted to the intensive care unit at Hospital Universitario de Canarias (Tenerife, Spain) who had a subclavian venous catheter. RESULTS: Patients with CHSS catheters (n = 353) had a lower incidence density of CRBSI (2.12 vs 0 out of 1,000 catheter-days; P = .02) and lower CVC-related cost per catheter-day (3.35 ± 3.75 vs 3.94 ± 9.95; P = .002) than those with standard catheters (n = 518). CHSS-impregnated catheters were associated with a lower risk of CRBSI (exact logistic regression) (odds ratio, 0.10; 95% confidence interval, -∞ to 0.667; P = .008) than standard catheters when controlling for catheter duration. CHSS-impregnated catheters were also associated with a lower CVC-related cost per catheter day than standard catheters (Poisson regression) (odds ratio, 0.85; 95% confidence interval, 0.001-0.873; P < .001). CONCLUSIONS: CHSS-impregnated catheters may be efficient in preventing CRBSI in patients with subclavian venous access.

Subglottic secretion drainage and continuous control of cuff pressure used together save health care costs.

BACKGROUND: Preventive strategies to reduce ventilator-associated respiratory infection (VARI) include the use of an endotracheal tube incorporating a lumen for subglottic secretion drainage (SSD) and a system for continuous control of endotracheal tube cuff pressure (CCCP). The health care costs associated with the combined use of these 2 measures aimed at preventing VARI are not known, however. The objective of this study was to determine whether the simultaneous use of these 2 preventive measures for VARI could save health care costs. METHODS: We performed a prospective observational study of patients who needed mechanical ventilation in an intensive care unit. The health care costs considered here included only the costs of the endotracheal tube, cuff control, and antimicrobials used to treat VARI. RESULTS: The study cohort comprised 656 patients, including 241 with intermittent control of cuff pressure and without SSD (standard group), 260 with CCCP and without SSD (CCCP group), 84 with intermittent control of cuff pressure and with SSD (SSD group), and 71 with CCCP and SSD (CCCP + SSD group). The incidence of VARI and health care costs were lower in the CCCP + SSD group compared with the standard, CCCP, and SSD groups. CONCLUSIONS: The combined use of SSD and CCCP reduced the incidence of VARI and saved health care costs.

Cost/benefit analysis of chlorhexidine-silver sulfadiazine-impregnated venous catheters for femoral access.

Sixty-four patients with chlorhexidine-silver sulfadiazine-impregnated catheters had a lower rate of catheter-related bloodstream infection and lower central venous catheter-related costs per catheter day than 190 patients with a standard catheter.

Continuous endotracheal tube cuff pressure control system protects against ventilator-associated pneumonia.

INTRODUCTION: The use of a system for continuous control of endotracheal tube cuff pressure reduced the incidence of ventilator-associated pneumonia (VAP) in one randomized controlled trial (RCT) with 112 patients but not in another RCT with 142 patients. In several guidelines on the prevention of VAP, the use of a system for continuous or intermittent control of endotracheal cuff pressure is not reviewed. The objective of this study was to compare the incidence of VAP in a large sample of patients (n = 284) treated with either continuous or intermittent control of endotracheal tube cuff pressure. METHODS: We performed a prospective observational study of patients undergoing mechanical ventilation during more than 48 hours in an intensive care unit (ICU) using either continuous or intermittent endotracheal tube cuff pressure control. Multivariate logistic regression analysis (MLRA) and Cox proportional hazard regression analysis were used to predict VAP. The magnitude of the effect was expressed as odds ratio (OR) or hazard ratio (HR), respectively, and 95% confidence interval (CI). RESULTS: We found a lower incidence of VAP with the continuous (n = 150) than with the intermittent (n = 134) pressure control system (22.0% versus 11.2%; p = 0.02). MLRA showed that the continuous pressure control system (OR = 0.45; 95% CI = 0.22-0.89; p = 0.02) and the use of an endotracheal tube incorporating a lumen for subglottic secretion drainage (SSD) (OR = 0.39; 95% CI = 0.19-0.84; p = 0.02) were protective factors against VAP. Cox regression analysis showed that the continuous pressure control system (HR = 0.45; 95% CI = 0.24-0.84; p = 0.01) and the use of an endotracheal tube incorporating a lumen for SSD (HR = 0.29; 95% CI = 0.15-0.56; p < 0.001) were protective factors against VAP. However, the interaction between type of endotracheal cuff pressure control system (continuous or intermittent) and endotracheal tube (with or without SSD) was not statistically significant in MLRA (OR = 0.41; 95% CI = 0.07-2.37; p = 0.32) or in Cox analysis (HR = 0.35; 95% CI = 0.06-1.84; p = 0.21). CONCLUSIONS: The use of a continuous endotracheal cuff pressure control system and/or an endotracheal tube with a lumen for SSD could help to prevent VAP in patients requiring more than 48 hours of mechanical ventilation.

Association between serum tissue inhibitor of matrix metalloproteinase-1 levels and mortality in patients with severe brain trauma injury.

OBJECTIVE: Matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) play a role in neuroinflammation after brain trauma injury (TBI). Previous studies with small sample size have reported higher circulating MMP-2 and MMP-9 levels in patients with TBI, but no association between those levels and mortality. Thus, the aim of this study was to determine whether serum TIMP-1 and MMP-9 levels are associated with mortality in patients with severe TBI. METHODS: This was a multicenter, observational and prospective study carried out in six Spanish Intensive Care Units. Patients with severe TBI defined as Glasgow Coma Scale (GCS) lower than 9 were included, while those with Injury Severity Score (ISS) in non-cranial aspects higher than 9 were excluded. Serum levels of TIMP-1, MMP-9 and tumor necrosis factor (TNF)-alpha, and plasma levels of tissue factor (TF) and plasminogen activator inhibitor (PAI)-1 plasma were measured in 100 patients with severe TBI at admission. Endpoint was 30-day mortality. RESULTS: Non-surviving TBI patients (n = 27) showed higher serum TIMP-1 levels than survivor ones (n = 73). We did not find differences in MMP-9 serum levels. Logistic regression analysis showed that serum TIMP-1 levels were associated 30-day mortality (OR = 1.01; 95% CI = 1.001-1.013; P = 0.03). Survival analysis showed that patients with serum TIMP-1 higher than 220 ng/mL presented increased 30-day mortality than patients with lower levels (Chi-square = 5.50; P = 0.02). The area under the curve (AUC) for TIMP-1 as predictor of 30-day mortality was 0.73 (95% CI = 0.624-0.844; P<0.001). An association between TIMP-1 levels and APACHE-II score, TNF- alpha and TF was found. CONCLUSIONS: The most relevant and new findings of our study, the largest series reporting data on TIMP-1 and MMP-9 levels in patients with severe TBI, were that serum TIMP-1 levels were associated with TBI mortality and could be used as a prognostic biomarker of mortality in TBI patients.

Chlorhexidine-silver sulfadiazine-impregnated venous catheters save costs.

BACKGROUND: Previous cost-effectiveness analyses have found that the use of chlorhexidine-silver sulfadiazine (CHSS)-impregnated catheters is associated with decreased catheter-related bloodstream infections (CRBSI) and central venous catheter (CVC)-related costs. However, in these analyses, the CVC-related cost included the increase of hospital stay. OBJECTIVE: Our aim was to determine the immediate CVC-related cost (including only the cost of CVC, diagnosis of CRBSI, and antimicrobials for the treatment of CRBSI) of using a CHSS or a standard catheter in internal jugular venous access. METHODS: We performed a prospective, observational, cohort study of patients admitted to the intensive care unit (ICU), Hospital Universitario de Canarias (Tenerife, Spain), who received 1 or more internal jugular venous catheters. RESULTS: The study included 245 CHSS-impregnated catheters and 391 standard catheters. Exact logistic regression analysis showed that CHSS-impregnated catheters were associated with a lower incidence of CRBSI, controlling for catheter duration, than standard catheters (0 vs 5.04 CRBSI per 1,000 catheter-days, respectively; odds ratio, 0.80; 95% confidence interval: 0.712-0.898; P < .001). Poisson regression showed that CHSS-impregnated catheters were associated with lower CVC-related cost per day than standard catheters (€3.78 ± €4.45 vs €7.28 ± €16.71, respectively; odds ratio, 0.52; 95% confidence interval: 0.504-0.535; P < .001). Survival analysis showed that CHSS-impregnated catheters were associated with increased CRBSI-free time compared with standard catheters (χ(2) = 14.9; P < .001). CONCLUSION: The use of CHSS-impregnated catheters reduced the incidence of CRBSI and immediate CVC-related costs in the internal jugular venous access.

Effect of nitrogen and phosphorus fertilization on the composition of rhizobacterial communities of two Chilean Andisol pastures.

The effect of nitrogen (N) and phosphorus (P) fertilization on composition of rhizobacterial communities of volcanic soils (Andisols) from southern Chile at molecular level is poorly understood. This paper investigates the composition of rhizobacterial communities of two Andisols under pasture after 1- and 6-year applications of N (urea) and P (triple superphosphate). Soil samples were collected from two previously established sites and the composition of rhizobacterial communities was determined by denaturing gradient gel electrophoresis (PCR-DGGE). The difference in the composition and diversity between rhizobacterial communities was assessed by nonmetric multidimensional scaling (MDS) analysis and the Shannon-Wiener index. In Site 1 (fertilized for 1 year), PCR-DGGE targeting 16S rRNA genes and MDS analysis showed that moderate N application (270 kg N ha(-1) year(-1)) without P significantly changed the composition of rhizobacterial communities. However, no significant community changes were observed with P (240 kg P ha(-1) year(-1)) and N-P application (270 kg N ha(-1) year(-1) plus 240 kg P ha(-1) year(-1)). In Site 2 (fertilized for 6 years with P; 400 kg P ha(-1) year(-1)), PCR-DGGE targeting rpoB, nifH, amoA and alkaline phosphatase genes and MDS analysis showed changes in rhizobacterial communities only at the highest rate of N application (600 kg N ha(-1) year(-1)). Quantitative PCR targeting 16S rRNA genes also showed higher abundance of bacteria at higher N application. In samples from both sites, the Shannon-Wiener index did not show significant difference in the diversity of rhizobacterial communities. The changes observed in rhizobacterial communities coincide in N fertilized pastures with lower soil pH and higher pasture yields. This study indicates that N-P application affects the soil bacterial populations at molecular level and needs to be considered when developing fertilizer practices for Chilean pastoral Andisols.

Safety and effectiveness of two treatment regimes with tranexamic acid to minimize inflammatory response in elective cardiopulmonary bypass patients: a randomized double-blind, dose-dependent, phase IV clinical trial.

BACKGROUND: In cardiopulmonary bypass (CPB) patients, fibrinolysis may enhance postoperative inflammatory response. We aimed to determine whether an additional postoperative dose of antifibrinolytic tranexamic acid (TA) reduced CPB-mediated inflammatory response (IR). METHODS: We performed a randomized, double-blind, dose-dependent, parallel-groups study of elective CPB patients receiving TA. Patients were randomly assigned to either the single-dose group (40 mg/Kg TA before CPB and placebo after CPB) or the double-dose group (40 mg/Kg TA before and after CPB). RESULTS: 160 patients were included, 80 in each group. The incident rate of IR was significantly lower in the double-dose-group TA2 (7.5% vs. 18.8% in the single-dose group TA1; P = 0.030). After adjusting for hypertension, total protamine dose and temperature after CPB, TA2 showed a lower risk of IR compared with TA1 [OR: 0.29 (95% CI: 0.10-0.83), (P = 0.013)]. Relative risk for IR was 2.5 for TA1 (95% CI: 1.02 to 6.12). The double-dose group had significantly lower chest tube bleeding at 24 hours [671 (95% CI 549-793 vs. 826 (95% CI 704-949) mL; P = 0.01 corrected-P significant] and lower D-dimer levels at 24 hours [489 (95% CI 437-540) vs. 621(95% CI: 563-679) ng/mL; P = 0.01 corrected-P significant]. TA2 required lower levels of norepinephrine at 24 h [0.06 (95% CI: 0.03-0.09) vs. 0.20(95 CI: 0.05-0.35) after adjusting for dobutamine [F = 6.6; P = 0.014 corrected-P significant]. We found a significant direct relationship between IL-6 and temperature (rho = 0.26; P < 0.01), D-dimer (rho = 0.24; P < 0.01), norepinephrine (rho = 0.33; P < 0.01), troponin I (rho = 0.37; P < 0.01), Creatine-Kinase (rho = 0.37; P < 0.01), Creatine Kinase-MB (rho = 0.33; P < 0.01) and lactic acid (rho = 0.46; P < 0.01) at ICU arrival. Two patients (1.3%) had seizure, 3 patients (1.9%) had stroke, 14 (8.8%) had acute kidney failure, 7 (4.4%) needed dialysis, 3 (1.9%) suffered myocardial infarction and 9 (5.6%) patients died. We found no significant differences between groups regarding these events. CONCLUSIONS: Prolonged inhibition of fibrinolysis, using an additional postoperative dose of tranexamic acid reduces inflammatory response and postoperative bleeding (but not transfusion requirements) in CPB patients. A question which remains unanswered is whether the dose used was ideal in terms of safety, but not in terms of effectiveness.

Lower associated costs using rifampicin-miconazole‒impregnated catheters compared with standard catheters.

Previous cost-effectiveness analyses found that antibiotic-impregnated catheters decrease the incidence of catheter-related bloodstream infection (CRBSI) as well as the costs related to central venous catheter (CVC) use, including increased hospital length of stay. The effect varied greatly among the studies, however. In this retrospective cohort study, compared with standard catheters, the use of rifampicin-miconazole-impregnated catheters was associated with lower CRBSI incidence and immediate CVC-related costs (taking into account only the costs of CVC, diagnosis, and treatment of CRBSI) (P < .001). Our data indicate that the use of rifampicin-miconazole-impregnated catheters can save associated costs.

Lower incidence of catheter-related bloodstream infection in cubital than in femoral artery access.

Data on catheter-related bloodstream infection (CRBSI) in cubital artery access are scarce. Thus, the objective of this study was to compare the incidence of CRBSI in a large series of patients with femoral or cubital artery catheters. We found 11 events of CRBSI in 1085 femoral artery catheters during 6497 days and none in 449 cubital artery catheters during 2709 days. Poisson regression analysis showed a higher incidence of CRBSI in femoral than in cubital artery site access (1.69 vs 0 CRBSI events per 1000 catheter-days; odds ratio 6.41, 95% confidence interval 1.05-infinite; p = 0.02). In conclusion, according to the results of our observational study, cubital artery access could have a lower risk of CRBSI than femoral artery access. However the development of randomized controlled trials is necessary before this conclusion can be definitively established. In addition, it is necessary to consider other potential mechanical complications when decision-making.

Platelet cytochrome c oxidase activity and quantity in septic patients.

OBJECTIVE: The cytopathic hypoxia theory proposes that there is an impaired cellular oxygen utilization during sepsis. Respiratory complex IV, or cytochrome c oxidase, was only previously studied in muscle biopsies of 16 surviving and 12 nonsurviving septic patients. We hypothesized that higher activities and quantities of this enzyme complex could be associated with septic patient survival. The objective was to evaluate the relationship between cytochrome c oxidase activities and quantities and 6-month survival in a larger series of septic patients using a less invasive method (circulating platelets). DESIGN: Prospective, multicenter, observational study. SETTING: The study was carried out in six Spanish intensive care units. PATIENTS: We included 96 septic patients. INTERVENTIONS: We determined the cytochrome c oxidase activity per citrate synthase activity ratio and cytochrome c oxidase quantity per citrate synthase activity ratio in circulating platelets at the time of diagnosis and related them to 6-month survival. The written informed consent from the family members was obtained. MEASUREMENTS AND MAIN RESULTS: Survivor patients (n = 54) showed higher cytochrome c oxidase activity per citrate synthase activity ratio (p = .04) and cytochrome c oxidase quantity per citrate synthase activity ratio (p = .006) than nonsurvivors (n = 42). Logistic regression analyses confirmed that the cytochrome c oxidase activity per citrate synthase activity ratio (p = .04) and cytochrome c oxidase quantity per citrate synthase activity ratio (p = .02) were independent predictors of 6-month survival. The area under the curve to predict 6-month survival was 0.62 (95% confidence interval 0.51-0.74; p = .04) for the cytochrome c oxidase activity per citrate synthase activity ratio and 0.67 (95% confidence interval 0.56-0.76; p = .003) for the cytochrome c oxidase quantity per citrate synthase activity ratio. A negative correlation was found between the cytochrome c oxidase quantity per citrate synthase activity ratio and Sepsis-Related Organ Failure Assessment score (p = .04). CONCLUSIONS: Platelet cytochrome c oxidase activity and quantity were independent predictors of 6-month survival and could be used as biomarkers of sepsis mortality. This is a rapid, easy, and less invasive protocol to assess mitochondrial function. Patients with lower cytochrome c oxidase activity and quantity could benefit from drugs that improve mitochondrial function.

Lower arterial catheter-related infection in brachial than in femoral access.

Recent guidelines do not establish a recommendation about the arterial catheter site to minimize the arterial catheter-related infection risk. In this prospective and observational study, we found a higher arterial catheter-related infection in 1085 arterial femoral sites than in 141 arterial brachial sites (5.08 vs 0 per 1000 catheter-days, respectively; odds ratio, 6.18; 95% confidence interval: 1.11-infinite; P = .02). Thus, arterial brachial access should be used in preference to femoral access.

Relative adrenal insufficiency and hemodynamic status in cardiopulmonary bypass surgery patients. A prospective cohort study.

BACKGROUND: The objectives of this study were to determine the risk factors for relative adrenal insufficiency in cardiopulmonary bypass patients and the impact on postoperative vasopressor requirements. METHODS: Prospective cohort study on cardiopulmonary bypass patients who received etomidate or not during anesthetic induction. Relative adrenal insufficiency was defined as a rise in serum cortisol

Matrix metalloproteinase-9, -10, and tissue inhibitor of matrix metalloproteinases-1 blood levels as biomarkers of severity and mortality in sepsis.

INTRODUCTION: Matrix metalloproteinases (MMPs) play a role in infectious diseases through extracellular matrix (ECM) degradation, which favors the migration of immune cells from the bloodstream to sites of inflammation. Although higher levels of MMP-9 and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) have been found in small series of patients with sepsis, MMP-10 levels have not been studied in this setting. The objective of this study was to determine the predictive value of MMP-9, MMP-10, and TIMP-1 on clinical severity and mortality in a large series of patients with severe sepsis. METHODS: This was a multicenter, observational, and prospective study carried out in six Spanish Intensive Care Units. We included 192 (125 surviving and 67 nonsurviving) patients with severe sepsis and 50 age- and sex-matched healthy controls in the study. Serum levels of MMP-9, MMP-10, TIMP-1, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-10 were measured in patients with severe sepsis at the time of diagnosis and in healthy controls. RESULTS: Sepsis patients had higher levels of MMP-10 and TIMP-1, higher MMP-10/TIMP-1 ratios, and lower MMP-9/TIMP-1 ratios than did healthy controls (P < 0.001). An association was found between MMP-9, MMP-10, TIMP-1, and MMP-9/TIMP-1 ratios and parameters of sepsis severity, assessed by the SOFA score, the APACHE-II score, lactic acid, platelet count, and markers of coagulopathy. Nonsurviving sepsis patients had lower levels of MMP-9 (P = 0.037), higher levels of TIMP-1 (P < 0.001), lower MMP-9/TIMP-1 ratio (P = 0.003), higher levels of IL-10 (P < 0.001), and lower TNF-alpha/IL-10 ratio than did surviving patients. An association was found between MMP-9, MMP-10, and TIMP-1 levels, and TNF-alpha and IL-10 levels. The risk of death in sepsis patients with TIMP-1 values greater than 531 ng/ml was 80% higher than that in patients with lower values (RR = 1.80; 95% CI = 1.13 to 2.87;P = 0.01; sensitivity = 0.73; specificity = 0.45). CONCLUSIONS: The novel findings of our study on patients with severe sepsis (to our knowledge, the largest series reporting data about MMP levels in sepsis) are that reduced MMP-9/TIMP-1 ratios and increased MMP-10 levels may be of great pathophysiologic significance in terms of severity and mortality, and that TIMP-1 levels may represent a biomarker to predict the clinical outcome of patients with sepsis.

Left atrial dysfunction and new-onset atrial fibrillation after cardiac surgery.

INTRODUCTION AND OBJECTIVES: Postoperative atrial fibrillation is a common complication of carrying out cardiac surgery with extracorporeal circulation (ECC). The aim of this study was to determine whether preoperative left atrial contractile dysfunction, as assessed by tissue Doppler echocardiography, is associated with the development of postoperative new-onset atrial fibrillation (PAF). METHODS: Transthoracic Doppler echocardiography was performed preoperatively in patients undergoing elective cardiac surgery. Left atrial contractile function was evaluated by tissue Doppler imaging (TDI) of the mitral annulus. RESULTS: The study included 92 patients in sinus rhythm preoperatively who underwent elective cardiac surgery with ECC: 73 (79%) were male and 19 (21%) were female, and their mean age was 67 (10) years. Of these, 19 (20.6%) developed PAF 34 (12) h postoperatively. Bivariate analysis showed that PAF was associated with older age (71 [7] years vs 66 [10] years; P=.034), a large left atrial diameter (LAD), and a low peak atrial systolic mitral annular velocity (A velocity) and a high mitral E/A ratio on TDI. Logistic regression analysis showed that PAF was independently associated with a large LAD (odds ratio [OR] =2.23; 95% confidence interval [CI], 1.05-4.76; P=.033) and a low A velocity (OR=0.70; 95% CI, 0.55-0.99; P=.034). CONCLUSIONS: Preoperative left atrial dysfunction, as assessed by TDI, was associated with an increased risk of PAF.

Clinical cure of ventilator-associated pneumonia treated with piperacillin/tazobactam administered by continuous or intermittent infusion.

The standard mode of administration of piperacillin treatment is by intermittent infusion. However, continuous infusion may be advantageous as beta-lactam antibiotics exhibit time-dependent antibacterial activity. In previous studies, we found a higher rate of clinical cure of ventilator-associated pneumonia (VAP) by continuous infusion rather than intermittent infusion of meropenem and ceftazidime. Therefore, the objective of this historical cohort study was to establish the clinical efficacy of piperacillin/tazobactam (PIP/TAZ) administered by continuous and intermittent infusion in the treatment of VAP in patients without renal failure. Logistic regression analysis showed a higher probability of clinical cure of VAP by continuous compared with intermittent infusion when the microorganism responsible for VAP had a minimum inhibitory concentration (MIC) of 8 microg/mL [8/9 (88.9%) vs. 6/15 (40.0%); odds ratio (OR)=10.79, 95% confidence interval (CI) 1.01-588.24; P=0.049] or 16 microg/mL [7/8 (87.5%) vs. 1/6 (16.7%); OR=22.89, 95% CI 1.19-1880.78; P=0.03]. Thus, administration of PIP/TAZ by continuous infusion may be considered more effective than intermittent infusion for the treatment of VAP caused by Gram-negative bacteria when the MIC of the microorganism responsible for VAP is 8-16 microg/mL in patients without renal failure.