Novel phenylalanine-modified magnetic ferroferric oxide nanoparticles for ciprofloxacin removal from aqueous solution.

The pollution of natural water bodies by pharmaceutical compounds has led to serious concerns regarding ecological and public health safety. In this study, novel recyclable phenylalanine (Phe)-modified magnetic ferroferric oxide nanoparticles (Fe3O4@Phe NPs) were successfully synthesized for the first time using a simple one-pot method to remove ciprofloxacin (CIP) from aqueous solutions. Fe3O4 and Fe3O4@Phe NPs were characterized using different techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Turbiscan analysis and vibrating-sample magnetometry (VSM). The results show that Fe3O4 NPs are fully encapsulated by Phe, exhibiting an average diameter of 200 nm, a high specific surface area (35.79 m2 g-1), good dispersion and superparamagnetic properties. The effects of Phe content, initial pH and ionic strength on CIP adsorption onto Fe3O4 and Fe3O4@Phe NPs are investigated. The maximal adsorption capacity of CIP onto Fe3O4@Phe NPs is determined to be 49.27 mg g-1. The adsorption kinetics and isotherms show that the adsorption process follows the pseudo-second-order-kinetic and Langmuir isotherm models, respectively. This indicates that the adsorption involves a rate-controlled monolayer chemisorption process. The regeneration experiments show that Fe3O4 and Fe3O4@Phe NPs exhibit good reusability for CIP adsorption. Adsorption mechanisms include electrostatic interactions, hydrogen bonding, hydrophobicity and π-π interactions. This study presents a promising strategy for the design and preparation of multifunctional nanoparticles to remove contaminants from the environment.

Safety application of muscle relaxants and the traditional low-frequency ventilation during the flexible or rigid bronchoscopy in patients with central airway obstruction: a retrospective observational study.

BACKGROUND: Bronchoscopy treatments of central airway obstruction (CAO) under general anesthesia are high-risky procedures, and posing a giant challenge to the anesthesiologists. We summarized and analyzed our clinical experience in patients with CAO undergoing flexible or rigid bronchoscopy, to estimate the safety of skeletal muscle relaxants application and the traditional Low-frequency ventilation. METHODS: Clinical data of 375 patients with CAO who underwent urgent endoscopic treatments in general anesthesia from January 2016 to October 2019 were retrospectively reviewed. The use ratio of skeletal muscle relaxants, dose of skeletal muscle relaxants used, the incidence of perioperative adverse events, adequacy of ventilation and gas exchange, post-operative recovery between rigid bronchoscopy and flexible bronchoscopy therapy, and risk factors for postoperative ICU admission were evaluated. RESULTS: Of the 375 patients with CAO, 204 patients were treated with flexible bronchoscopy and 171 patients were treated with rigid bronchoscopy. Muscle relaxants were used in 362 of 375 patients (including 313 cisatracurium, 45 rocuronium, 4 atracurium, and 13 unrecorded). The usage rate of muscle relaxants (96.5% in total) was very high in patients with CAO who underwent either flexible bronchoscopy (96.6%) or rigid bronchoscopy (96.5%) therapy. The dosage of skeletal muscle relaxants (Cisatracium) used was higher in rigid bronchoscopy compared with flexible bronchoscopy therapy (10.8 ± 3.8 VS 11.6 ± 3.6 mg, respectively, p < 0.05). No patient suffered the failure of ventilation, bronchospasm and intraoperative cough either in flexible or rigid bronchoscopy therapy. Hypoxemia was occurred in 13 patients (8 in flexible, 5 in rigid bronchoscopy) during the procedure, and reintubation after extubation happened in 2 patients with flexible bronchoscopy. Sufficient ventilation was successfully established using the traditional Low-frequency ventilation with no significant carbon dioxide accumulation and hypoxemia occurred both in flexible and rigid bronchoscopy group (p > 0.05). Three patients (1 in flexible and 2 in rigid) died, during the post-operative recovery, and the higher grade of American Society of Anesthesiologists (ASA) and obvious dyspnea or orthopnea were the independent risk factors for postoperative ICU admission. CONCLUSION: The muscle relaxants and low-frequency traditional ventilation can be safely used both in flexible and rigid bronchoscopy treatments in patients with CAO. These results may provide strong clinical evidence for optimizing the anesthesia management of bronchoscopy for these patients.

Heteroresistance to cefepime in Pseudomonas aeruginosa bacteraemia.

INTRODUCTION: Heteroresistance to antibiotic agents can lead to diagnostic and therapeutic failures; however, to date, cefepime heteroresistance (FEP-HR) in Pseudomonas aeruginosa (P. aeruginosa) bacteraemia has not been characterised. The primary goal of this study was to investigate the molecular epidemiology, mechanisms and risk factors for cefepime-heteroresistant P. aeruginosa bacteraemia over approximately 6 years in Southwest China. RESULTS: A high prevalence (57.3%) of heteroresistance to cefepime was observed during the study period, and these FEP-HR isolates were not clonally related. Mechanistic studies revealed that AmpC hyperproduction contributed to the development of this phenomenon. In addition, patients with advanced age, haematological malignancies, central venous catheters, and previous cephalosporin therapy were identified as independent risk factors for acquiring FEP-HR P. aeruginosa bacteraemia. Furthermore, patients infected with FEP-HR were generally at a greater risk for an adverse prognosis compared with those with non-FEP-HR. More importantly, characterisation of three successive P. aeruginosa isolates recovered from the same patient revealed that heteroresistance can act as an intermediate stage during the evolution from susceptibility to full resistance in patients undergoing antibiotic therapy for prolonged periods. CONCLUSION: These findings emphasised the necessity of antimicrobial stewardship programs in clinical settings, as well as the need for some rapid screening methods for detecting this phenomenon.

Corrigendum: Carbapenem-Resistant E. cloacae in Southwest China: Molecular Analysis of Resistance and Risk Factors for Infections Caused by NDM-1-Producers.

[This corrects the article DOI: 10.3389/fmicb.2018.00658.].

Carbapenem-Resistant E. cloacae in Southwest China: Molecular Analysis of Resistance and Risk Factors for Infections Caused by NDM-1-Producers.

Carbapenem-resistant Enterobacteriaceae (CRE) has been considered a serious global threat, but carbapenem resistance remains relatively uncommon in E. cloacae, especially in China. The aim of this study was to characterize carbapenem-resistant E. cloacae (CR-ECL) isolates from 2012 to 2016 in Southwest China. Our study revealed that 20 (15.2%) of the 132 CR-ECL isolates obtained from patients were identified as NDM-1, with most isolates carrying the IncFIIA plasmids. Notably, we initially observed that the E. cloacae strain co-harbored NDM-1 and IMP-8 carbapenemases simultaneously. Analysis of the genetic environment of these two genes has revealed that the highly conserved regions (blaNDM-1-bleMBL-trpF-tat) are associated with the dissemination of NDM-1, while IS26, intI1, and tniC could be involved in the spread of IMP-8. Molecular epidemiology studies showed the nosocomial outbreak caused by NDM-1-producing E. cloacae ST88. Transferring from another hospital and previous carbapenem exposure were identified as independent risk factors for the acquisition of NDM-1-producing E. cloacae. These findings emphasize the need for intensive surveillance and precautions to monitor the further spread of NDM-1 in China.

Functionalization of Nanodiamond with Four Kinds of Expoxies.

In this work, a simple and effective method for the covalent functionalization of nanodiamond (ND) with four epoxies has been developed. After homogenization by mixed acids and thionyl chlorides, the surface of ND was modified with triethylenetetramine (TETA) to possess amine groups, which were used as active points to react with epoxy by ring opening reaction. Four different epoxies used are bifunctional diglycidyl ether of bisphenol-A (DGEBA), trifunctional triglycidyl p-amino phenol (TGAP), tetrafunctional tetraglycidyldiamino diphenylmethane (TGDDM) and bisphenol-A novolac epoxy resin (BAEPN). FT-IR spectra revealed that the epoxy was covalently attached to the ND (ND-g-epoxy). In addition, functionalized ND particles were characterized with WAXD and UV-Vis spectra to confirm the result. The weight gains as a result of the epoxy-functionalized ND were determined by TGA analysis. The ND-g-epoxy particles were better dispersed in common organic solvents and the average diameters were characterized. The better dispersion and of the modified ND were identified from the SEM images.

[Preparation and application of polyclonal antibody against Ras-related C3 botulinum toxin substrate 1].

OBJECTIVE: To prepare rabbit polyclonal antibody (pAb) against Ras-related C3 botulinum toxin substrate 1 (Rac1) and identify the functions of the antibody. METHODS: The Rac1 fragment was amplified from cDNA of human cervical cancer HeLa cells, and then inserted into the vector pET-32a to construct the recombinant plasmid pET-32a-Rac1. The recombinant protein Rac1 was fused with His-tag and the fusion protein His-Rac1 was expressed in E.coli expression system. Thereafter, His-tagged Rac1 was purified to immunize rabbits as immunogen. The titer and specificity of rabbit polyclonal antibody against Rac1 were identified by ELISA, Western blotting and immunohistochemistry, respectively. RESULTS: The fusion protein His-Rac1 was successfully expressed in E.coli. The pAb could specifically detect Rac1 in human HeLa cells and MCF-7 cells in Western blotting. Moreover, the pAb could specifically recognized Rac1 protein in human kidney tissues. CONCLUSION: The pAb of human Rac1 protein was successfully prepared, which could specifically recognize Rac1 protein in several natural samples.

Retrospective analysis of hospital-acquired linezolid-nonsusceptible enterococci infection in Chongqing, China, 2011-2014.

BACKGROUND: Linezolid-nonsusceptible enterococci (LNSE) is an increasingly emerging multidrug-resistant pathogen, and the caused nosocomial infections are difficult to manage. However, data on the host-related risk factors and clinical outcomes for LNSE infection are poorly characterized. METHODS: A retrospective case-case-control study of risk factors and clinical outcomes of hospitalized patients with LNSE infection during the period 2011-2014 was conducted in a teaching hospital in Chongqing, China. Case patients with LNSE and those with linezolid-susceptible enterococci (LSE) and controls with no enterococcal infection were compared at a ratio of 1:1:4. Two parallel multivariate logistic regression models were used to evaluate independent predictors for acquiring LNSE and LSE, respectively. RESULTS: Forty-four LNSE cases, 44 LSE cases, and 176 uninfected controls were analyzed. Multivariable analysis indicated that transferring from another hospital (odds ratio [OR], 3.57; 95% confidence interval [CI], 1.58-8.09), peripheral vascular disease (OR, 4.36; 95% CI, 1.64-11.60), and exposure to cephalosporins (OR, 4.24; 95% CI, 1.85-9.71) were unique independent predictors for acquiring LNSE. Gallbladder disease (OR, 3.64; 95% CI, 1.36-9.74) was independently associated with LSE acquisition. Polymicrobial infection was the only factor identified in both LNSE and LSE groups compared with controls; however, no statistical significance was observed in in-hospital mortality. CONCLUSION: Timely control efforts and appropriate antibiotic stewardship programs are necessary to effectively reduce the burden of LNSE infections among high-risk patients.