Designed polyelectrolyte shell on magnetite nanocore for dilution-resistant biocompatible magnetic fluids.

Magnetite nanoparticles (MNPs) coated with poly(acrylic acid-co-maleic acid) polyelectrolyte (PAM) have been prepared with the aim of improving colloidal stability of core-shell nanoparticles for biomedical applications and enhancing the durability of the coating shells. FTIR-ATR measurements reveal two types of interaction of PAM with MNPs: hydrogen bonding and inner-sphere metal-carboxylate complex formation. The mechanism of the latter is ligand exchange between uncharged -OH groups of the surface and -COO(-) anionic moieties of the polyelectrolyte as revealed by adsorption and electrokinetic experiments. The aqueous dispersion of PAM@MNP particles (magnetic fluids - MFs) tolerates physiological salt concentration at composition corresponding to the plateau of the high-affinity adsorption isotherm. The plateau is reached at small amount of added PAM and at low concentration of nonadsorbed PAM, making PAM highly efficient for coating MNPs. The adsorbed PAM layer is not desorbed during dilution. The performance of the PAM shell is superior to that of poly(acrylic acid) (PAA), often used in biocompatible MFs. This is explained by the different adsorption mechanisms; metal-carboxylate cannot form in the case of PAA. Molecular-level understanding of the protective shell formation on MNPs presented here improves fundamentally the colloidal techniques used in core-shell nanoparticle production for nanotechnology applications

Simple scoring system to predict in-hospital mortality after surgery for infective endocarditis

BACKGROUND: Aspecific scoring systems are used to predict the risk of death postsurgery in patients with infective endocarditis (IE). The purpose of the present study was both to analyze the risk factors for in-hospital death, which complicates surgery for IE, and to create a mortality risk score based on the results of this analysis. METHODS AND RESULTS: Outcomes of 361 consecutive patients (mean age, 59.1\ub115.4 years) who had undergone surgery for IE in 8 European centers of cardiac surgery were recorded prospectively, and a risk factor analysis (multivariable logistic regression) for in-hospital death was performed. The discriminatory power of a new predictive scoring system was assessed with the receiver operating characteristic curve analysis. Score validation procedures were carried out. Fifty-six (15.5%) patients died postsurgery. BMI >27 kg/m2 (odds ratio [OR], 1.79; P=0.049), estimated glomerular filtration rate 55 mm Hg (OR, 1.78; P=0.032), and critical state (OR, 2.37; P=0.017) were independent predictors of in-hospital death. A scoring system was devised to predict in-hospital death postsurgery for IE (area under the receiver operating characteristic curve, 0.780; 95% CI, 0.734-0.822). The score performed better than 5 of 6 scoring systems for in-hospital death after cardiac surgery that were considered. CONCLUSIONS: A simple scoring system based on risk factors for in-hospital death was specifically created to predict mortality risk postsurgery in patients with IE

Applicability of Pulse Pressure Variation during Unstable Hemodynamic Events in the Intensive Care Unit: A Five-Day Prospective Multicenter Study

International audienc

First report of Klebsiella quasipneumoniae harboring bla(KPC-2) in Saudi Arabia

Background Nosocomial infections caused by multi-drug resistant Enterobacteriaceae are a global public health threat that ought to be promptly identified, reported, and addressed accurately. Many carbapenem-resistant Enterobacteriaceae-associated genes have been identified in Saudi Arabia but not the endemic Klebsiella pneumoniae carbapenemases (KPCs), which are encoded by bla(KPC-type) genes. KPCs are known for their exceptional spreading potential. Methods We collected n = 286 multi-drug resistant (MDR) Klebsiella spp. isolates as part of screening for resistant patterns from a tertiary hospital in Saudi Arabia between 2014 and 2018. Antimicrobial susceptibility testing was carried out using both VITEK II and the broth microdilution of all collected isolates. Detection of resistance-conferring genes was carried out using Illumina whole-genome shotgun sequencing and PacBio SMRT sequencing protocols. Results A Carbapenem-resistant Enterobacteriaceae (CRE) Klebsiella quasipneumoniae subsp. similipneumoniae strain was identified as a novel ST-3510 carrying a bla(KPC-2) carbapenemase encoding gene. The isolate, designated as NGKPC-421, was obtained from shotgun Whole Genome Sequencing (WGS) surveillance of 286 MDR Klebsiella spp. clinical isolates. The NGKPC-421 isolate was collected from a septic patient in late 2017 and was initially misidentified as K. pneumoniae. The sequencing and assembly of the NGKPC-421 genome resulted in the identification of a putative similar to 39.4 kb IncX6 plasmid harboring a bla(KPC-2) gene, flanked by transposable elements (ISKpn6-bla(KPC-2)-ISKpn27). Conclusion This is the first identification of a KPC-2-producing CRE in the Gulf region. The impact on this finding is of major concern to the public health in Saudi Arabia, considering that it is the religious epicenter with a continuous mass influx of pilgrims from across the world. Our study strongly highlights the importance of implementing rapid sequencing-based technologies in clinical microbiology for precise taxonomic classification and monitoring of antimicrobial resistance patterns

First report of Klebsiella quasipneumoniae harboring bla KPC-2 in Saudi Arabia

Background: Nosocomial infections caused by multi-drug resistant Enterobacteriaceae are a global public health threat that ought to be promptly identified, reported, and addressed accurately. Many carbapenem-resistant Enterobacteriaceae-associated genes have been identified in Saudi Arabia but not the endemic Klebsiella pneumoniae carbapenemases (KPCs), which are encoded by bla genes. KPCs are known for their exceptional spreading potential. Methods: We collected n = 286 multi-drug resistant (MDR) Klebsiella spp. isolates as part of screening for resistant patterns from a tertiary hospital in Saudi Arabia between 2014 and 2018. Antimicrobial susceptibility testing was carried out using both VITEK II and the broth microdilution of all collected isolates. Detection of resistance-conferring genes was carried out using Illumina whole-genome shotgun sequencing and PacBio SMRT sequencing protocols. Results: A Carbapenem-resistant Enterobacteriaceae (CRE) Klebsiella quasipneumoniae subsp. similipneumoniae strain was identified as a novel ST-3510 carrying a bla carbapenemase encoding gene. The isolate, designated as NGKPC-421, was obtained from shotgun Whole Genome Sequencing (WGS) surveillance of 286 MDR Klebsiella spp. clinical isolates. The NGKPC-421 isolate was collected from a septic patient in late 2017 and was initially misidentified as K. pneumoniae. The sequencing and assembly of the NGKPC-421 genome resulted in the identification of a putative ~ 39.4 kb IncX6 plasmid harboring a bla gene, flanked by transposable elements (ISKpn6-bla -ISKpn27). Conclusion: This is the first identification of a KPC-2-producing CRE in the Gulf region. The impact on this finding is of major concern to the public health in Saudi Arabia, considering that it is the religious epicenter with a continuous mass influx of pilgrims from across the world. Our study strongly highlights the importance of implementing rapid sequencing-based technologies in clinical microbiology for precise taxonomic classification and monitoring of antimicrobial resistance patterns