Incidence, associated disease burden and healthcare utilization due to Staphylococcus aureus prosthetic joint infection in European hospitals: the COMBACTE-NET ARTHR-IS multi-centre study.

BACKGROUND: The aim of this study was to estimate the incidence, associated disease burden and healthcare utilization due to Staphylococcus aureus prosthetic joint infections (SA-PJI) after primary hip and knee arthroplasty in European centres. METHODS: This study was conducted in patients who underwent primary hip and knee arthroplasty in 19 European hospitals between 2014 and 2016. The global incidence of PJI and SA-PJI was calculated. The associated disease burden was measured indirectly as infection-related mortality plus loss of function. For healthcare utilization, number and duration of hospitalizations, number and type of surgical procedures, duration of antibiotic treatments, and number of outpatient visits were collected. Subgroup and regression analyses were used to evaluate the impact of SA-PJI on healthcare utilization, controlling for confounding variables. RESULTS: The incidence of PJI caused by any micro-organism was 1.41%, and 0.40% for SA-PJI. Among SA-PJI, 20.7% were due to MRSA with substantial regional differences, and were more frequent in partial hip arthroplasty (PHA). Related deaths and loss of function occurred in 7.0% and 10.2% of SA-PJI cases, respectively, and were higher in patients with PHA. Compared with patients without PJI, patients with SA-PJI had a mean of 1.4 more readmissions, 25.1 more days of hospitalization, underwent 1.8 more surgical procedures, and had 5.4 more outpatient visits, controlling for confounding variables. Healthcare utilization was higher in patients who failed surgical treatment of SA-PJI. CONCLUSIONS: This study confirmed that the SA-PJI burden is high, especially in PHA, and provided a solid basis for planning interventions to prevent SA-PJI.

SARS-CoV-2 ORF8 accessory protein is a virulence factor.

IMPORTANCE: The relevance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ORF8 in the pathogenesis of COVID-19 is unclear. Virus natural isolates with deletions in ORF8 were associated with wild milder disease, suggesting that ORF8 might contribute to SARS-CoV-2 virulence. This manuscript shows that ORF8 is involved in inflammation and in the activation of macrophages in two experimental systems: humanized K18-hACE2 transgenic mice and organoid-derived human airway cells. These results identify ORF8 protein as a potential target for COVID-19 therapies.

[Impact of days elapsed from the onset of symptoms to hospitalization in COVID-19 in-hospital mortality: Time matters]. / Impacto de los días transcurridos desde el inicio de los síntomas hasta la hospitalización en la mortalidad hospitalaria por COVID-19: el tiempo importa.

Background: COVID-19 shows different clinical and pathophysiological stages over time. Theeffect of days elapsed from the onset of symptoms (DEOS) to hospitalization on COVID-19prognostic factors remains uncertain. We analyzed the impact on mortality of DEOS to hospital-ization and how other independent prognostic factors perform when taking this time elapsedinto account. Methods: This retrospective, nationwide cohort study, included patients with confirmed COVID-19 from February 20th and May 6th, 2020. The data was collected in a standardized online datacapture registry. Univariate and multivariate COX-regression were performed in the generalcohort and the final multivariate model was subjected to a sensitivity analysis in an earlypresenting (EP; < 5 DEOS) and late presenting (LP; ≥5 DEOS) group. Results: 7915 COVID-19 patients were included in the analysis, 2324 in the EP and 5591 in theLP group. DEOS to hospitalization was an independent prognostic factor of in-hospital mortalityin the multivariate Cox regression model along with other 9 variables. Each DEOS incrementaccounted for a 4.3% mortality risk reduction (HR 0.957; 95% CI 0.93---0.98). Regarding variationsin other mortality predictors in the sensitivity analysis, the Charlson Comorbidity Index onlyremained significant in the EP group while D-dimer only remained significant in the LP group. Conclusion: When caring for COVID-19 patients, DEOS to hospitalization should be consideredas their need for early hospitalization confers a higher risk of mortality. Different prognosticfactors vary over time and should be studied within a fixed timeframe of the disease.

Impacto de los días transcurridos desde el inicio de los síntomas hasta la hospitalización en la mortalidad hospitalaria por COVID-19: el tiempo importa / Impact of days elapsed from the onset of symptoms to hospitalization in COVID-19 in-hospital mortality: Time matters

Antecedentes La COVID-19 muestra diferentes fases clínicas y fisiopatológicas a lo largo del tiempo. El efecto de los días transcurridos desde el comienzo de los síntomas (DTCS) hasta la hospitalización sobre los factores pronósticos de la COVID-19 sigue siendo incierto. Analizamos el impacto en la mortalidad de los DTCS hasta la hospitalización y cómo se comportan otros factores pronósticos independientes al tener en cuenta dicho tiempo transcurrido. Métodos En este estudio de cohortes nacional retrospectivo se incluyó a pacientes con COVID-19 confirmada entre el 20 de febrero y el 6 de mayo de 2020. Los datos se recopilaron en un registro normalizado de captura de datos en línea. Se realizó una regresión de Cox uni y multifactorial en la cohorte general y el modelo multifactorial final se sometió a un análisis de sensibilidad en un grupo de presentación precoz (PP) < 5 DTCS y otro de presentación tardía (PT) ≥ 5 DTCS). Resultados En el análisis se incluyó a 7.915 pacientes con COVID-19, 2.324 en el grupo de PP y 5.591 en el de PT. Los DTCS hasta la hospitalización fueron un factor pronóstico independiente de mortalidad intrahospitalaria en el modelo de regresión de Cox multifactorial junto con otras nueve variables. Cada incremento en un DTCS supuso una reducción del riesgo de mortalidad del 4,3% (RRI = 0,957; IC 95%, 0,93-0,98). En cuanto a las variaciones de otros factores predictivos de la mortalidad en el análisis de sensibilidad, únicamente el índice de comorbilidad de Charlson siguió siendo significativo en el grupo de PP, mientras que únicamente el dímero D lo siguió siendo en el grupo de PT. Conclusiones Al atender a pacientes con COVID-19 hay que tener en cuenta los DTCS hasta la hospitalización porque la necesidad de hospitalización precoz confiere un mayor riesgo de mortalidad. Los diferentes factores pronósticos varían con el tiempo y deberían estudiarse dentro de un marco temporal fijo de la enfermedad (AU)

Background COVID-19 shows different clinical and pathophysiological stages over time. Theeffect of days elapsed from the onset of symptoms (DEOS) to hospitalization on COVID-19prognostic factors remains uncertain. We analyzed the impact on mortality of DEOS to hospital-ization and how other independent prognostic factors perform when taking this time elapsedinto account. Methods This retrospective, nationwide cohort study, included patients with confirmed COVID-19 from February 20th and May 6th, 2020. The data was collected in a standardized online datacapture registry. Univariate and multivariate COX-regression were performed in the generalcohort and the final multivariate model was subjected to a sensitivity analysis in an earlypresenting (EP; <5 DEOS) and late presenting (LP; ≥5 DEOS) group. Results 7915 COVID-19 patients were included in the analysis, 2324 in the EP and 5591 in theLP group. DEOS to hospitalization was an independent prognostic factor of in-hospital mortalityin the multivariate Cox regression model along with other 9 variables. Each DEOS incrementaccounted for a 4.3% mortality risk reduction (HR 0.957; 95% CI 0.93---0.98). Regarding variationsin other mortality predictors in the sensitivity analysis, the Charlson Comorbidity Index onlyremained significant in the EP group while D-dimer only remained significant in the LP group. Conclusion When caring for COVID-19 patients, DEOS to hospitalization should be consideredas their need for early hospitalization confers a higher risk of mortality. Different prognosticfactors vary over time and should be studied within a fixed timeframe of the disease (AU)

Impact of days elapsed from the onset of symptoms to hospitalization in COVID-19 in-hospital mortality: time matters.

BACKGROUND: COVID-19 shows different clinical and pathophysiological stages over time. The effect of days elapsed from the onset of symptoms (DEOS) to hospitalization on COVID-19 prognostic factors remains uncertain. We analyzed the impact on mortality of DEOS to hospitalization and how other independent prognostic factors perform when taking this time elapsed into account. METHODS: This retrospective, nationwide cohort study, included patients with confirmed COVID-19 from February 20th and May 6th, 2020. The data was collected in a standardized online data capture registry. Univariate and multivariate COX-regression were performed in the general cohort and the final multivariate model was subjected to a sensitivity analysis in an early presenting (EP; <5 DEOS) and late presenting (LP; ≥5 DEOS) group. RESULTS: 7915 COVID-19 patients were included in the analysis, 2324 in the EP and 5591 in the LP group. DEOS to hospitalization was an independent prognostic factor of in-hospital mortality in the multivariate Cox regression model along with other 9 variables. Each DEOS increment accounted for a 4.3% mortality risk reduction (HR 0.957; 95% CI 0.93-0.98). Regarding variations in other mortality predictors in the sensitivity analysis, the Charlson Comorbidity Index only remained significant in the EP group while D-dimer only remained significant in the LP group. CONCLUSION: When caring for COVID-19 patients, DEOS to hospitalization should be considered as their need for early hospitalization confers a higher risk of mortality. Different prognostic factors vary over time and should be studied within a fixed timeframe of the disease.

Antimicrobial resistance in Gram-negative bacilli in Spain: an experts' view.

BACKGROUND: Antibiotic resistance in Gram-negative bacilli poses a serious problem for public health. In hospitals, in addition to high mortality rates, the emergence and spread of resistance to practically all antibiotics restricts therapeutic options against serious and frequent infections. OBJECTIVE: The aim of this work is to present the views of a group of experts on the following aspects regarding resistance to antimicrobial agents in Gram-negative bacilli: 1) the current epidemiology in Spain, 2) how it is related to local clinical practice and 3) new therapies in this area, based on currently available evidence. METHODS: After reviewing the most noteworthy evidence, the most relevant data on these three aspects were presented at a national meeting to 99 experts in infectious diseases, clinical microbiology, internal medicine, intensive care medicine, anaesthesiology and hospital pharmacy. RESULTS AND CONCLUSIONS: Subsequent local debates among these experts led to conclusions in this matter, including the opinion that the approval of new antibiotics makes it necessary to train the specialists involved in order to optimise how they use them and improve health outcomes; microbiology laboratories in hospitals must be available throughout a continuous timetable; all antibiotics must be available when needed and it is necessary to learn to use them correctly; and the Antimicrobial Stewardship Programs (ASP) play a key role in quickly allocating the new antibiotics within the guidelines and ensure appropriate use of them.

The early use of sepsis scores to predict respiratory failure and mortality in non-ICU patients with COVID-19.

This observational retrospective study aimed to investigate the usefulness of Sequential Organ Failure Assessment (SOFA), Quick SOFA (qSOFA), National Early Warning Score (NEWS), and quick NEWS in predicting respiratory failure and death among patients with COVID-19 hospitalized outside of intensive care units (ICU). We included 237 adults hospitalized with COVID-19 who were followed-up on for one month or until death. Respiratory failure was defined as a PaO2/FiO2 ratio ≤200mmHg or the need for mechanical ventilation. Respiratory failure occurred in 77 patients (32.5%), 29 patients (12%) were admitted to the ICU, and 49 patients (20.7%) died. Discrimination of respiratory failure was slightly higher in NEWS, followed by SOFA. Regarding mortality, SOFA was more accurate than the other scores. In conclusion, sepsis scores are useful for predicting respiratory failure and mortality in COVID-19 patients. A NEWS score ≥4 was found to be the best cutoff point for predicting respiratory failure.

Utilidad de las escalas de sepsis para predecir el fallo respiratorio y la muerte en pacientes con COVID-19 fuera de las Unidades de Cuidados Intensivos / The early use of sepsis scores to predict respiratory failure and mortality in non-ICU patients with COVID-19

El presente estudio retrospectivo observacional tiene como objetivo analizar la utilidad de las escalas SOFA (Sequential Organ Failure Assessment), qSOFA (Quick SOFA), NEWS (National Early Warning Score ) y Quick NEWS para predecir el fallo respiratorio y la muerte en pacientes con COVID-19 atendidos fuera de la Unidad de Cuidados Intensivos (UCI). Se incluyeron 237 adultos con COVID-19 hospitalizados seguidos durante un mes o hasta su fallecimiento. El fallo respiratorio se definió como un cociente PaO2/FiO2 ≤ 200 mmHg o la necesidad de ventilación mecánica. Setenta y siete pacientes (32,5%) desarrollaron fallo ventilatorio; 29 (12%) precisaron ingreso en UCI, y 49 fallecieron (20,7%). La discriminación del fallo ventilatorio fue algo mayor con la puntuación NEWS, seguida de la SOFA. En cuanto a la mortalidad, la puntuación SOFA fue más exacta que las otras escalas. En conclusión, las escalas de sepsis son útiles para predecir el fallo respiratorio y la muerte en COVID-19. Una puntuación ≥ 4 en la escala NEWS sería el mejor punto de corte para predecir fallo respiratorio (AU)

This observational retrospective study aimed to investigate the usefulness of Sequential Organ Failure Assessment (SOFA), Quick SOFA (qSOFA), National Early Warning Score (NEWS), and quick NEWS in predicting respiratory failure and death among patients with COVID-19 hospitalized outside of intensive care units (ICU). We included 237 adults hospitalized with COVID-19 who were followed-up on for one month or until death. Respiratory failure was defined as a PaO2/FiO2 ratio ≤ 200 mmHg or the need for mechanical ventilation. Respiratory failure occurred in 77 patients (32.5%), 29 patients (12%) were admitted to the ICU, and 49 patients (20.7%) died. Discrimination of respiratory failure was slightly higher in NEWS, followed by SOFA. Regarding mortality, SOFA was more accurate than the other scores. In conclusion, sepsis scores are useful for predicting respiratory failure and mortality in COVID-19 patients. A NEWS score ≥ 4 was found to be the best cutoff point for predicting respiratory failure (AU)

[The early use of sepsis scores to predict respiratory failure and mortality in non-ICU patients with COVID-19]. / Utilidad de las escalas de sepsis para predecir el fallo respiratorio y la muerte en pacientes con COVID-19 fuera de las Unidades de Cuidados Intensivos.

This observational retrospective study aimed to investigate the usefulness of Sequential Organ Failure Assessment (SOFA), Quick SOFA (qSOFA), National Early Warning Score (NEWS), and quick NEWS in predicting respiratory failure and death among patients with COVID-19 hospitalized outside of intensive care units (ICU). We included 237 adults hospitalized with COVID-19 who were followed-up on for one month or until death. Respiratory failure was defined as a PaO2/FiO2 ratio ≤ 200 mmHg or the need for mechanical ventilation. Respiratory failure occurred in 77 patients (32.5%), 29 patients (12%) were admitted to the ICU, and 49 patients (20.7%) died. Discrimination of respiratory failure was slightly higher in NEWS, followed by SOFA. Regarding mortality, SOFA was more accurate than the other scores. In conclusion, sepsis scores are useful for predicting respiratory failure and mortality in COVID-19 patients. A NEWS score ≥ 4 was found to be the best cutoff point for predicting respiratory failure.

Staphylococcus aureus native arthritis over 10 years.

OBJECTIVES: Septic arthritis is associated with significant case fatality and morbidity. Staphylococcus aureus is the most common cause of arthritis. We aimed to analyze the microbiological features of S. aureus causing native arthritis and to investigate their influence on the clinical outcome of the infection. PATIENTS AND METHODS: We conducted a retrospective study including all episodes of S. aureus native arthritis between 2005-2015. Phenotypic (antimicrobial susceptibility, ß-hemolysis, agr functionality, biofilm formation) and genotypic characteristics (pulsed-field gel electrophoresis, DNA microarrays) were investigated. The primary endpoint was microbiological failure of treatment, including infection relapse, persistence, or attributable death. RESULTS: Twenty-nine patients were included (65.5% of men, mean age: 59): seven (24.1%) patients presenting with methicillin-resistant S. aureus (MRSA) native arthritis and 19 with methicillin-susceptible S. aureus (MSSA) native arthritis. Treatment failure occurred in seven (26.9%) patients (4/7 patients [57.1%] among MRSA infections vs. 3/19 [15.8%] among MSSA infections). The persistence rate was similar in MRSA and MSSA infections (1/7 vs. 3/19). However, the case fatality was significantly higher in patients with MRSA infection (3/7 vs. 0/19). The most frequent clonal complex (CC) was CC5 (38.1%). MSSA showed higher genetic variability (nine CCs) versus MRSA (3 CCs). CONCLUSIONS: Beyond methicillin resistance, we did not find phenotypic or genotypic factors associated with the poor outcome of S. aureus native arthritis. CC5 was the major CC, showing the higher genetic variability of MSSA versus MRSA.

Safety and Efficacy of Prolonged Use of Dalbavancin in Bone and Joint Infections.

Dalbavancin is a lipoglycopeptide with potent activity against Gram-positive microorganisms, a long half-life, a favorable safety profile, and a high concentration in bone, which makes it an interesting alternative for treatment of osteoarticular infections. We performed a multicentric retrospective study of all patients with an osteoarticular infection (septic arthritis, spondylodiscitis, osteomyelitis, or orthopedic implant-related infection) treated with at least one dose of dalbavancin between 2016 and 2017 in 30 institutions in Spain. In order to evaluate the response, patients with or without an orthopedic implant were separated. A total of 64 patients were included. Staphylococcus epidermidis and Staphylococcus aureus were the most frequent microorganisms. The reasons for switching to dalbavancin were simplification (53.1%), adverse events (25%), or failure (21.9%). There were 7 adverse events, and no patient had to discontinue dalbavancin. In 45 cases, infection was related to an orthopedic implant. The implant material was retained in 23 cases, including that in 15 (65.2%) patients that were classified as cured and 8 (34.8%) that presented improvement. In 21 cases, the implants were removed, including those in 16 (76.2%) cases that were considered successes, 4 (19%) cases were considered improved, and 1 (4.8%) case that was considered a failure. Among the 19 cases without implants, 14 (73.7%) were considered cured, 3 (15.8%) were considered improved, and 2 (10.5%) were considered failures. The results show that dalbavancin is a well-tolerated antibiotic, even when >2 doses are administered, and is associated with a high cure rate. These are preliminary data with a short follow-up; therefore, it is necessary to gain more experience and, in the future, to establish the most appropriate dose and frequency.

Staphylococcus aureus meningitis in adults: A comparative cohort study of infections caused by meticillin-resistant and meticillin-susceptible strains.

BACKGROUND: Staphylococcus aureus meningitis is an uncommon nosocomial infection usually associated with neurosurgical procedures, but spontaneous infections may occasionally appear. AIMS: To compare the features of meningitis caused by meticillin-resistant (MRSA) and meticillin-susceptible (MSSA) S. aureus and examine the prognostic factors for mortality, including MRSA infection and combined antimicrobial therapy. METHODS: Retrospective cohort study of 350 adults with S. aureus meningitis admitted to 11 hospitals in Spain (1981-2015). Logistic regression and propensity score matching were used to analyse prognostic factors. RESULTS: There were 118 patients (34%) with MRSA and 232 (66%) with MSSA. Postoperative infection (91% vs 73%) and nosocomial acquisition (93% vs 74%) were significantly more frequent in MRSA than in MSSA meningitis (P < 0.001). Combined therapy was given to 118 (34%) patients. Overall 30-day mortality rate was 23%. On multivariate analysis, mortality was associated with severe sepsis or shock (odds ratio (OR) 9.9, 95% confidence interval (CI) 4.5-22.0, P < 0.001), spontaneous meningitis (OR 4.2, 95% CI 1.9-9.1, P < 0.001), McCabe-Jackson score rapidly or ultimately fatal (OR 2.8, 95% CI 1.4-5.4, P = 0.002), MRSA infection (OR 2.6, 95% CI 1.3-5.3, P = 0.006), and coma (OR 2.6, 95% CI 1.1-6.1, P < 0.029). In postoperative cases, mortality was related to retention of cerebrospinal devices (OR 7.9, 95% CI 3.1-20.3, P < 0.001). CONCLUSIONS: Clinical and epidemiological differences between MRSA and MSSA meningitis may be explained by the different pathogenesis of postoperative and spontaneous infection. In addition to the severity of meningitis and underlying diseases, MRSA infection was associated with increased mortality. Combined antimicrobial therapy was not associated with increased survival.

IgE promotes type 2 innate lymphoid cells in murine food allergy.

BACKGROUND: Mast cells serve an important sentinel function at mucosal barriers and have been implicated as key early inducers of type 2 immune responses in food allergy. The generation of Th2 and IgE following food allergen ingestion is inhibited in the absence of mast cells. Group 2 innate lymphoid cells are also thought to play an important early role in nascent allergic responses. OBJECTIVE: To test whether IgE-mediated mast cell activation promotes intestinal ILC2 responses following ingestion of food allergens and whether ILC2 amplify food allergy. METHODS: Two different mouse models of food allergy, one using intraperitoneally ovalbumin (OVA)-primed BALB/c animals and the other using enterally peanut-sensitized inherently atopic IL4raF709 mice, were applied to test the contributions of IgE antibodies and mast cells to ILC2 responses. The effect of ILC2 on mast cell activation and on anaphylaxis was tested. RESULTS: ILC2 responses were significantly impaired in both models of food allergy in Igh7-/- mice harbouring a targeted deletion of the gene encoding IgE. A similar reduction in food allergen-induced ILC2 was observed in mast cell-deficient Il4raF709 KitW-sh mice, and this was partially corrected by reconstituting these animals using cultured bone marrow mast cells. Mast cells activated ILC2 for IL-13 production in an IL-4Rα-dependent manner. Activated ILC2 amplified systemic anaphylaxis by increasing target tissue sensitivity to mast cell mediators. CONCLUSIONS AND CLINICAL RELEVANCE: These findings support an important role for IgE-activated mast cells in driving intestinal ILC2 expansion in food allergy and reveal that ILC2, in turn, can enhance responsiveness to the mediators of anaphylaxis produced by mast cells. Strategies designed to inhibit IgE signalling or mast cell activation are likely to inhibit both type 2 immunity and immediate hypersensitivity in food allergy.

Mexican consensus on dyspepsia. / Consenso mexicano sobre la dispepsia.

Since the publication of the 2007 dyspepsia guidelines of the Asociación Mexicana de Gastroenterología, there have been significant advances in the knowledge of this disease. A systematic search of the literature in PubMed (01/2007 to 06/2016) was carried out to review and update the 2007 guidelines and to provide new evidence-based recommendations. All high-quality articles in Spanish and English were included. Statements were formulated and voted upon using the Delphi method. The level of evidence and strength of recommendation of each statement were established according to the GRADE system. Thirty-one statements were formulated, voted upon, and graded. New definition, classification, epidemiology, and pathophysiology data were provided and include the following information: Endoscopy should be carried out in cases of uninvestigated dyspepsia when there are alarm symptoms or no response to treatment. Gastric and duodenal biopsies can confirm Helicobacter pylori infection and rule out celiac disease, respectively. Establishing a strong doctor-patient relationship, as well as dietary and lifestyle changes, are useful initial measures. H2-blockers, proton-pump inhibitors, prokinetics, and antidepressants are effective pharmacologic therapies. H.pylori eradication may be effective in a subgroup of patients. There is no evidence that complementary and alternative therapies are beneficial, with the exception of Iberogast and rikkunshito, nor is there evidence on the usefulness of prebiotics, probiotics, or psychologic therapies. The new consensus statements on dyspepsia provide guidelines based on up-to-date evidence. A discussion, level of evidence, and strength of recommendation are presented for each statement.

Mass and stiffness spectrometry of nanoparticles and whole intact bacteria by multimode nanomechanical resonators.

The identification of species is a fundamental problem in analytical chemistry and biology. Mass spectrometers identify species by their molecular mass with extremely high sensitivity (<10-24 g). However, its application is usually limited to light analytes (<10-19 g). Here we demonstrate that by using nanomechanical resonators, heavier analytes can be identified by their mass and stiffness. The method is demonstrated with spherical gold nanoparticles and whole intact E. coli bacteria delivered by electrospray ionization to microcantilever resonators placed in low vacuum at 0.1 torr. We develop a theoretical procedure for obtaining the mass, position and stiffness of the analytes arriving the resonator from the adsorption-induced eigenfrequency jumps. These results demonstrate the enormous potential of this technology for identification of large biological complexes near their native conformation, a goal that is beyond the capabilities of conventional mass spectrometers.

Outcome of patients with streptococcal prosthetic joint infections with special reference to rifampicin combinations.

BACKGROUND: Outcome of patients with streptococcal prosthetic joint infections (PJIs) is not well known. METHODS: We performed a retrospective multicenter cohort study that involved patients with total hip/knee prosthetic joint (THP/TKP) infections due to Streptococcus spp. from 2001 through 2009. RESULTS: Ninety-five streptococcal PJI episodes (50 THP and 45 TKP) in 87 patients of mean age 69.1 ± 13.7 years met the inclusion criteria. In all, 55 out of 95 cases (57.9 %) were treated with debridement and retention of the infected implants with antibiotic therapy (DAIR). Rifampicin-combinations, including with levofloxacin, were used in 52 (54.7 %) and 28 (29.5 %) cases, respectively. After a mean follow-up period of 895 days (IQR: 395-1649), the remission rate was 70.5 % (67/95). Patients with PJIs due to S. agalactiae failed in the same proportion as in the other patients (10/37 (27.1 %) versus 19/58 (32.7 %); p = .55). In the univariate analysis, antibiotic monotherapy, DAIR, antibiotic treatments other than rifampicin-combinations, and TKP were all associated with a worse outcome. The only independent variable significantly associated with the patients' outcomes was the location of the prosthesis (i.e., hip versus knee) (OR = 0.19; 95 % CI 0.04-0.93; p value 0.04). CONCLUSIONS: The prognosis of streptococcal PJIs may not be as good as previously reported, especially for patients with an infected total knee arthroplasty. Rifampicin combinations, especially with levofloxacin, appear to be suitable antibiotic regimens for these patients.

Significance of the isolation of Staphylococcus aureus from a central venous catheter tip in the absence of concomitant bacteremia: a clinical approach.

The optimal approach following the isolation of Staphylococcus aureus from an intravascular catheter tip in the absence of concomitant bacteremia remains unclear. We aimed to determine the rate of delayed complications in these patients. We performed a retrospective observational study (during the period 2002-2012) including patients with a catheter tip culture yielding S. aureus. Patients were followed up for ≥6 months. The primary endpoint was the occurrence of delayed staphylococcal complications (either bacteremia and/or metastatic distant infections). A total of 113 patients were included (75 % male, median age 61 years): 46 and 67 with negative and positive blood cultures, respectively. We found a lower rate of delayed staphylococcal complications in cases with no bacteremia within 48 h since catheter removal than in cases of confirmed S. aureus catheter-related bacteremia (0.0 % vs. 25.4 %; p-value < 0.001). In the group without bacteremia, there was a subgroup of 15 patients (32.6 %) who did not receive antimicrobial treatment. Again, delayed complications occurred less commonly in this subgroup of patients without bacteremia (0.0 % vs. 25.4 %; p-value = 0.033). In contrast to patients with S. aureus catheter-related bacteremia, no delayed infectious complications were observed in patients with an isolated catheter tip culture yielding S. aureus and negative blood cultures within 48 h of catheter removal. Futures studies are needed to assess if the therapeutic approach could be different for this group of patients.

How two-dimensional bending can extraordinarily stiffen thin sheets.

Curved thin sheets are ubiquitously found in nature and manmade structures from macro- to nanoscale. Within the framework of classical thin plate theory, the stiffness of thin sheets is independent of its bending state for small deflections. This assumption, however, goes against intuition. Simple experiments with a cantilever sheet made of paper show that the cantilever stiffness largely increases with small amounts of transversal curvature. We here demonstrate by using simple geometric arguments that thin sheets subject to two-dimensional bending necessarily develop internal stresses. The coupling between the internal stresses and the bending moments can increase the stiffness of the plate by several times. We develop a theory that describes the stiffness of curved thin sheets with simple equations in terms of the longitudinal and transversal curvatures. The theory predicts experimental results with a macroscopic cantilever sheet as well as numerical simulations by the finite element method. The results shed new light on plant and insect wing biomechanics and provide an easy route to engineer micro- and nanomechanical structures based on thin materials with extraordinary stiffness tunability.

Spatially multiplexed dark-field microspectrophotometry for nanoplasmonics.

Monitoring the effect of the substrate on the local surface plasmon resonance (LSPR) of metallic nanoparticles is key for deepening our understanding of light-matter interactions at the nanoscale. This coupling gives rise to shifts of the LSPR as well as changes in the scattering pattern shape. The problem requires of high-throughput techniques that present both high spatial and spectral resolution. We present here a technique, referred to as Spatially Multiplexed Micro-Spectrophotometry (SMMS), able to perform polarization-resolved spectral and spatial analysis of the scattered light over large surface areas. The SMMS technique provides three orders of magnitude faster spectroscopic analysis than conventional dark-field microspectrophotometry, with the capability for mapping the spatial distribution of the scattered light intensity with lateral resolution of 40 nm over surface areas of 0.02 mm(2). We show polarization-resolved dark-field spectral analysis of hundreds of gold nanoparticles deposited on a silicon surface. The technique allows determining the effect of the substrate on the LSPR of single nanoparticles and dimers and their scattering patterns. This is applied for rapid discrimination and counting of monomers and dimers of nanoparticles. In addition, the diameter of individual nanoparticles can be rapidly assessed with 1 nm accuracy.