In-host intra- and inter-species transfer of blaKPC-2 and blaNDM-1 in Serratia marcescens and its local and global epidemiology.

OBJECTIVES: This study aimed to investigate interspecies transfer of resistance gene blaNDM-1 and intraspecies transfer of blaKPC-2 in Serratia marcescens, and explore the epidemical and evolutionary characteristics of carbapenemase-producing S. marcescens (CPSM) regionally and globally. METHODS: Interspecies and intraspecies transfer of blaKPC-2- or blaNDM-1 were identified by antimicrobial susceptibility testing, plasmid conjugation and curing, discovery of transposable units (TUs), outer membrane vesicles (OMVs), qPCR, whole-genome sequencing and bioinformatic analysis. The genomic evolution of CPSM strains was explored by cgSNP and maximum-likelihood phylogenetic tree. RESULTS: CPSM S50079 strain, co-carrying blaKPC-2 and blaNDM-1 on one plasmid, was isolated from the blood of a patient with acute pancreatitis and could generate TUs carrying either blaKPC-2 or blaNDM-1. We identified the interspecies transfer of blaNDM-1-carrying plasmid from Providencia rettgeri P50213, producing the identical blaNDM-1-carrying TUs, to S. marcescens S50079K, an S50079 variant via plasmid curing, through blaNDM-1-harboring plasmid conjugation and OMVs transfer. Furthermore, the intraspecies transfer of blaKPC-2, mediated by IS26 from plasmid to chromosome in S50079, was identified. Likely, in another lung transplant patient, interspecies transfer of blaNDM-1 carried by IncX3 plasmid was also identified among S. marcescens and Citrobacter freundii as well as Enterobacter hormaechei via plasmid transfer. Furthermore, 11 CPSM from 349 non-repetitive S. marcescens strains were identified in the same hospital and clonal dissemination, with carbapenemase evolution from blaKPC-2 to both blaKPC-2 and blaNDM-1 was found in the 8 CPSM across four years. Finally, the analysis of 236 global CPSM from 835 non-repetitive S. marcescens genomes, retrieved from NCBI database, revealed long-term spread and evolution worldwide, and would cause the convergence of more carbapenemase genes. CONCLUSIONS: Interspecies transfer of resistance gene blaNDM-1 and intraspecies transfer of resistance gene blaKPC-2 in CPSM were identified. Nosocomial and global dissemination of CPSM were revealed and more urgent surveillance was acquired.

Liraglutide alleviates ferroptosis in renal ischemia reperfusion injury via inhibiting macrophage extracellular trap formation.

BACKGROUND AND PURPOSE: Renal transplantation and other conditions with transiently reduced blood flow is major cause of renal ischemia/reperfusion injury (RIRI), a therapeutic challenge clinically. This study investigated the role of liraglutide in ferroptosis-associated RIRI via macrophage extracellular traps (METs). METHODS: Animal model with RIRI was established in C57BL/6J mice. A total of 72 C57BL/6J mice were used with 8 mice per group. Primary tubular epithelium was co-culture with RAW264.7 under hypoxia/reoxygenation (H/R) condition to mimic in vitro. Liraglutide was administrated into mice and cells. Extracellular DNA, neutrophil elastase and myeloperoxidase in serum and supernatant of cell medium were collected for measuring METs. F4/80 and citH3 were labeled to show METs. RESULTS: Liraglutide relieved RIRI and ferroptosis in vivo, and inhibited renal I/R-induced METs both in vivo and in vitro. F4/80 and citrullinated histone H3 (citH3) were highly co-localized after RIRI. Liraglutide attenuated the co-localization of citH3 and F4/80. Expressions of M2 markers were enhanced whereas these of M1 markers suppressed during liraglutide treatment in RIRI. Phosphorylation of signal transducer and activator of transcription (STAT)1, 3 and 6 were increased in RIRI mice and H/R-induced RAW264.7. However, liraglutide decreased phosphorylation of STAT1 and increased phosphorylation of STAT3 and STAT6. STAT3/6 inhibition reversed liraglutide-inhibited M1 polarization, extracellular traps and ferroptosis. CONCLUSION: Liraglutide inhibited ferroptosis-induced renal dysfunction since it skewed macrophage polarization into M2 phenotype that interfered the formation of extracellular traps based on STAT3/6 pathway during RIRI. Liraglutide was proposed to be used for RIRI clinical treatment.

Two outbreaks and sporadic occurrences of Candida auris from one hospital in China: an epidemiological, genomic retrospective study.

OBJECTIVES: To investigate the clinical relevance, origin, transmission, and resistance of Candida auris (C. auris) isolates from two outbreaks and sporadic occurrences from one hospital in China. METHODS: A total of 135 C. auris isolates were collected. Clinical characteristics were obtained and antifungal susceptibility testing (AFST) was performed using the method of broth microdilution. Phylogenetic tree, WGS analysis, and single nucleotide polymorphisms (SNPs) were used to determine the origin, transmission, and resistance mechanisms. RESULTS: A total of 31 patients (91.2%, 31/34) received invasive medical procedures and 13 patients (38.2%, 13/34) had antifungal agents before C. auris infection/colonization, except one patient whose clinical information was missing. Only 4 cases of C. auris candidemia were observed. 18 patients died, 13 patients recovered, and the outcomes of 3 patients were not available. A total of 35 C. auris isolates, which were successfully cultivated and the first isolated or harbored specific drug-resistant phenotype from each patient, were selected to be sequenced and further analyzed. C. auris isolates presented low genetic variability and belonged to clade I, possibly originating from BJ004-H7 in Beijing. All 35 isolates were resistant to Fluconazole (FCZ) and amphotericin B (AMB), and 3 isolates were resistant to caspofungin (CAS). Mutations in ERG11 and FKS1 were linked to reduced azole and echinocandin susceptibility, respectively. CONCLUSIONS: Two outbreaks of highly clonal, multidrug-resistant C. auris isolates within the medical facility were reported. The intensive performance of disinfection measures helped block in-hospital transmission. Understanding the epidemiology, drug resistance and management of C. auris will be helpful for implementing effective infection control and treatment strategies.

Bioinspired radiative cooling coating with high emittance and robust self-cleaning for sustainably efficient heat dissipation.

To overcome the overheating phenomena of electronic devices and energy components, developing advanced energy-free cooling coatings with promising radiative property seem an effective and energy-saving way. However, the further application of these coatings is greatly limited by their sustainability because of their fragile and easy contamination. Herein, it is reported that a bioinspired radiative cooling coating (BRCC) displayed sustainably efficient heat dissipation by the combination of high emittance and robust self-cleaning property. With the hierarchical porous structure constructed by multiwalled carbon nanotubes (MWCNTs), modified SiO2 and fluorosilicone (FSi) resin, the involvement of the BRCC improves the cooling performance by increasing ≈25% total heat transfer coefficient. During the abrasion and soiling tests, the BRCC-coated Al alloy heat sink always displays stable radiative cooling performance. Moreover, the simulation and experimental results both revealed that reducing surface coverage of BRCC (≈80.9%) can still keep highly cooling efficiency, leading to a cost-effective avenue. Therefore, this study may guide the design and fabrication of advanced radiative cooling coating.

Identification of bladder cancer subtypes and predictive signature for prognosis, immune features, and immunotherapy based on immune checkpoint genes.

Immunotherapy based on immune checkpoint genes (ICGs) has recently made significant progress in the treatment of bladder cancer patients, but many patients still cannot benefit from it. In the present study, we aimed to perform a comprehensive analysis of ICGs in bladder cancer tissues with the aim of evaluating patient responsiveness to immunotherapy and prognosis. We scored ICGs in each BLCA patient from TCGA and GEO databases by using ssGSEA and selected genes that were significantly associated with ICGs scores by using the WCGNA algorithm. NMF clustering analysis was performed to identify different bladder cancer molecular subtypes based on the expression of ICGs-related genes. Based on the immune related genes differentially expressed among subgroups, we further constructed a novel stratified model containing nine genes by uni-COX regression, LASSO regression, SVM algorithm and multi-COX regression. The model and the nomogram constructed based on the model can accurately predict the prognosis of bladder cancer patients. Besides, the patients classified based on this model have large differences in sensitivity to immunotherapy and chemotherapy, which can provide a reference for individualized treatment of bladder cancer.

Influence of ABC stroke score on late recurrence of paroxysmal atrial fibrillation following radiofrequency catheter ablation.

BACKGROUND: In this study we investigated the impact of ABC stroke score on the recurrence of paroxysmal atrial fibrillation (PAF) following radiofrequency catheter ablation (RFCA). METHODS: A total of 132 patients with PAF who underwent RFCA from October 2018 to September 2019 were included in this study. During the first phase of this study the patients were categorized into two groups based on late recurrence of atrial fibrillation after RFCA. In the second phase, the patients were further divided into two groups based on whether their ABC stroke score was ≥ 6.5. RESULT: The univariate analysis indicated that the risk factors for late recurrence of PAF included early recurrence, ABC stroke score, CHA2DS2-VASc score, and NT-proBNP (P < 0.05). Cox multivariate regression analysis revealed that ABC stroke score (P = 0.006) and early recurrence (P = 0.000) were independent predictors of late recurrence, and ABC stroke score ≥ 6.5 was a risk for predicting recurrence of PAF after RFCA with a sensitivity of 66.7% and specificity of 65.7%. After the completion of the 1:1 matching, the univariate Cox analysis indicated that an elevated score of ABC stroke (≥ 6.5) was an independent predictor of late recurrence of PAF (HR = 2.687, 95% CI: 1.036-6.971, P = 0.042). However, using an ABC stroke score cut off at 6.4 predicted the recurrence of atrial tachyarrhythmia with 85% sensitivity and 58.5% specificity. CONCLUSION: An ABC stroke score ≥ 6.4 is a predictor for late recurrence of PAF after RFCA.

Effects of intensive, targeted education by pharmacists on anticoagulant patients with atrial fibrillation: a multicenter randomized controlled trial from China.

AIMS: Many people diagnosed with atrial fibrillation (AF) may lack awareness of AF and anticoagulants. The purpose of this study is to investigate the effects of intensive, targeted education by pharmacists on anticoagulant patients with AF. METHODS AND RESULTS: Three hundred seventy-six AF patients were randomly assigned to receive standard care or pharmacist education. Follow-up is scheduled after 1, 3, 6, and 12 months. Pharmacists provided intensive education on knowledge deficits revealed by the Jessa Atrial Fibrillation Knowledge Questionnaire (JAKQ) during each visit. Patients also completed two questionnaires to assess their medication adherence and satisfaction. Clinical outcomes were recorded during follow-up. 361 patients completed follow-up. Baseline scores on the JAKQ were similar in the education group (median: 31.3%) and the standard care group (median: 31.3%) (p = 0.911). Over time, the knowledge score of the education group increased significantly (1 month: 68.8%, 3 months: 81.3%; P <0.001), while there was no significant improvement in the standard care group (1 month: 37.5%, 3 months: 37.5%; P = 0.314). Adherence scores improved significantly over time in the education group (P < 0.001) but not in the standard care group (P =0.101). Compared with standard care, pharmacist education was associated with a significantly lower risk of bleeding (P=0.034). CONCLUSIONS: Given the knowledge deficiency of AF patients in China, standardized patient education should be a part of their daily care. Pharmacist-led education intervention can significantly improve the disease-related knowledge, medication adherence, and drug treatment satisfaction of AF patients while significantly reducing the risk of bleeding.

Insights into the effects of coating and single crystallization on the rate performance and cycle life of LiNi0.9Mn0.1O2 cathode.

Coating and single crystal are two common strategies for cobalt-free nickel-rich layered oxides to solve its poor rate performance and cycle stability. However, the action mechanism of different modification protocols to suppress the attenuation are unclear yet. Herein, the Li2MoO4 layer-coated polycrystalline LiNi0.9Mn0.1O2 (1.0 %-Mo + NM91) and single crystal LiNi0.9Mn0.1O2 (SC-NM91) are prepared to investigate this difference, respectively. By focusing on the interior of particles, the relationship between structure evolution and electrochemical behavior is systematically studied, and the intrinsic mechanism of coating/single-crystallization modifications on suppressing the attenuation is clarified. The results show that microcracks in LiNi0.9Mn0.1O2 (NM91) are the main culprit leading to the rate capability decay, and the coating can effectively prevent the radial diffusion of microcracks from the center to surface, inhibiting the generation of surface side reactions. Therefore, the coating has a more advantage in improving the rate performance at 5.0C, the discharge capacity of 1.0 %-Mo + NM91 (130.6 mAh/g) is 7.9 % higher than that of SC-NM91 (121.0 mAh/g). In contrast, the single-crystallization can effectively prevent the formation of intergranular cracks arising from the anisotropic stress in NM91, which causes the severe cycle degradation. Correspondingly, the grain boundary-free SC-NM91 shows superior cyclability. The capacity retention rate of SC-NM91 (80.8 %) at 0.2C after 100cycles is 6.3 % higher than that of 1.0 %-Mo + NM91 (74.5 %). This work concludes the effect difference of different modification methods on enhancing the electrochemical performance, which provides theoretical and technical guidance for the optimized and targeted modification design in the cobalt-free high nickel cathode materials.

A terahertz meta-sensor array for 2D strain mapping.

Large-scale stretchable strain sensor arrays capable of mapping two-dimensional strain distributions have gained interest for applications as wearable devices and relating to the Internet of Things. However, existing strain sensor arrays are usually unable to achieve accurate directional recognition and experience a trade-off between high sensing resolution and large area detection. Here, based on classical Mie resonance, we report a flexible meta-sensor array that can detect the in-plane direction and magnitude of preloaded strains by referencing a dynamically transmitted terahertz (THz) signal. By building a one-to-one correspondence between the intrinsic electrical/magnetic dipole resonance frequency and the horizontal/perpendicular tension level, arbitrary strain information across the meta-sensor array is accurately detected and quantified using a THz scanning setup. Particularly, with a simple preparation process of micro template-assisted assembly, this meta-sensor array offers ultrahigh sensor density (~11.1 cm-2) and has been seamlessly extended to a record-breaking size (110 × 130 mm2), demonstrating its promise in real-life applications.

Multiscale Heterogeneities-Based Piezoresistive Interfaces with Ultralow Detection Limitation and Adaptively Switchable Pressure Detectability.

Mechanical compliance and electrical enhancement are crucial for pressure sensors to promote performances when perceiving external stimuli. Here we propose a bioinspired multiscale heterogeneity-based interface to adaptively regulate its structure layout and switch to desirable piezoresistive behaviors with ultralow detection limitation. In such a multiscale heterogeneities system, the micro-/nanoscale spiny Ag-MnO2 heterostructure contributes to an ultralow detection limitation of 0.008 Pa and can perceive minor pressure increments under preloads with high resolution (0.0083%). The macroscale heterogeneous orientation of the cellular backbone enables anisotropic deformation, allowing the sensor to switch to rational sensitivity and working range (e.g., 580 kPa-1 for 0-20 kPa/54 kPa-1 for 60-140 kPa) as required. The sensor's stepwise activation progresses from the micro-/nanoscale heterostructure to the macroscale heterogeneous orientation, which can adaptively match diverse sensing tasks in complex applications scenarios. This multiscale heterogeneous and switchable design holds immense potential in the development of intelligent electromechanical devices, including wearable sensors, soft robotics, and smart actuators.

Coexistence of virulent and multidrug-resistant plasmids in an uropathogenic Escherichia coli.

OBJECTIVES: The emergence of pathogens co-harbouring multiple mobile resistance and virulence elements is of great concern in clinical settings. Herein, we report an O101: H10-ST167 Escherichia coli Hu106 strain isolated from the urinary tract of a female in China. METHODS: Antibiotic susceptibility testing was used to present the antimicrobial resistance spectrum. Whole-genome sequencing (WGS) and bioinformatic analysis were used to clarify the virulent and resistance mechanisms. Furthermore, the virulence of this strain was tested by the Greater wax moth larvae and siderophore production experiment. RESULTS: The strain E. coli Hu106 was resistant to almost all antimicrobials tested, and only susceptible to aztreonam, amikacin, and tigecycline. WGS analysis revealed that the strain Hu106 co-harboured blaNDM-9 and mcr-1 on p2-Hu106, belonging to IncHI2/IncHI2A (256,000 bp). The co-existence of both resistance genes, blaNDM-9 and mcr-1, on the plasmid p2-Hu106 was mainly acquired by transposition recombination of mobile antibiotic elements mediated by IS26 and/or IS1 on IncHI2/IncHI2A type plasmid. In addition, the virulence clusters aerobactin (iutA-iucABCD) and salmochelin (iroBCDEN) were identified on an IncFIB/IncFIC(IncFII) type plasmid p1-Hu106, flanked by small mobile elements such as IS1A, ISkpn28, and IS3, respectively. After performing genomic comparison of p1-Hu106 with the WGS in NCBI, we identified that the virulent plasmid p1-Hu106-like could spread in different clones of E. coli and Klebsiella pneumoniae, revealing its underlying dissemination mechanism between Enterobacterales. Furthermore, the strain caused a decreased survival rate of larvae and produced high siderophore units (62.33%), similar to hypervirulent K. pneumoniae NTUH-K2044. CONCLUSIONS: The strains co-carrying the multidrug-resistant plasmid p2-Hu106 and virulent plasmid p1-Hu106 should be closely monitored to prevent its further spreading.

Skin-Inspired Multi-Modal Mechanoreceptors for Dynamic Haptic Exploration.

Active sensing is a fundamental aspect of human and animal interactions with the environment, providing essential information about the hardness, texture, and tackiness of objects. This ability stems from the presence of diverse mechanoreceptors in the skin, capable of detecting a wide range of stimuli and from the sensorimotor control of biological mechanisms. In contrast, existing tactile sensors for robotic applications typically excel in identifying only limited types of information, lacking the versatility of biological mechanoreceptors and the requisite sensing strategies to extract tactile information proactively. Here, inspired by human haptic perception, a skin-inspired artificial 3D mechanoreceptor (SENS) capable of detecting multiple mechanical stimuli is developed to bridge sensing and action in a closed-loop sensorimotor system for dynamic haptic exploration. A tensor-based non-linear theoretical model is established to characterize the 3D deformation (e.g., tensile, compressive, and shear deformation) of SENS, providing guidance for the design and optimization of multimode sensing properties with high fidelity. Based on SENS, a closed-loop robotic system capable of recognizing objects with improved accuracy (≈96%) is further demonstrated. This dynamic haptic exploration approach shows promise for a wide range of applications such as autonomous learning, healthcare, and space and deep-sea exploration.

An Antidehydration Hydrogel Based on Zwitterionic Oligomers for Bioelectronic Interfacing.

Hydrogels are ideal interfacing materials for on-skin healthcare devices, yet their susceptibility to dehydration hinders their practical use. While incorporating hygroscopic metal salts can prevent dehydration and maintain ionic conductivity, concerns arise regarding metal toxicity due to the passage of small ions through the skin barrier. Herein, an antidehydration hydrogel enabled by the incorporation of zwitterionic oligomers into its network is reported. This hydrogel exhibits exceptional water retention properties, maintaining ≈88% of its weight at 40% relative humidity, 25 °C for 50 days and about 84% after being heated at 50 °C for 3 h. Crucially, the molecular weight design of the embedded oligomers prevents their penetration into the epidermis, as evidenced by experimental and molecular simulation results. The hydrogel allows stable signal acquisition in electrophysiological monitoring of humans and plants under low-humidity conditions. This research provides a promising strategy for the development of epidermis-safe and biocompatible antidehydration hydrogel interfaces for on-skin devices.

Comparison of Second-Generation Cryoballoon Ablation and Quantitative Radiofrequency Ablation Guided by Ablation Index for Atrial Fibrillation.

We compared the efficacy and complication rates of quantitative radiofrequency ablation guided by ablation index (RFCA-AI) with those of second-generation cryoballoon ablation (CBA-2). Consecutive patients (n = 230) with symptomatic atrial fibrillation (AF) undergoing a first ablation CBA-2 (92 patients) or RFCA-AI (138 patients) procedure were enrolled in this study. The late recurrence rate in the CBA-2 group was higher than that in the RFCA-AI group (P = .012). Subgroup analysis showed the same result in patients with paroxysmal AF (PAF) (P = .039), but no difference was found in patients with persistent AF (P = .21). The average operation duration in the CBA-2 group (85 [75-99.5] minutes) was shorter than that in the RFCA-AI group (100 [84.5-120] minutes) (P < .0001), but the average exposure time (17.36(13.87-22.49) vs 5.49(4.00-8.24) minutes) in the CBA-2 group and X-ray dose (223.25(149.15-336.95) vs 109.15(80.75-168.7) mGym) were significantly longer than those in RFCA-AI group (P < .0001). Multivariate logistic regression analysis showed that left atrial diameter (LAD), early recurrence, and methods of ablation (cryoballoon ablation) were independent risk factors for late recurrence after AF ablation. Early recurrence of AF and LAD were independent risk factors for predicting late recurrence after AF ablation.

Water-responsive supercontractile polymer films for bioelectronic interfaces.

Connecting different electronic devices is usually straightforward because they have paired, standardized interfaces, in which the shapes and sizes match each other perfectly. Tissue-electronics interfaces, however, cannot be standardized, because tissues are soft1-3 and have arbitrary shapes and sizes4-6. Shape-adaptive wrapping and covering around irregularly sized and shaped objects have been achieved using heat-shrink films because they can contract largely and rapidly when heated7. However, these materials are unsuitable for biological applications because they are usually much harder than tissues and contract at temperatures higher than 90 °C (refs. 8,9). Therefore, it is challenging to prepare stimuli-responsive films with large and rapid contractions for which the stimuli and mechanical properties are compatible with vulnerable tissues and electronic integration processes. Here, inspired by spider silk10-12, we designed water-responsive supercontractile polymer films composed of poly(ethylene oxide) and poly(ethylene glycol)-α-cyclodextrin inclusion complex, which are initially dry, flexible and stable under ambient conditions, contract by more than 50% of their original length within seconds (about 30% per second) after wetting and become soft (about 100 kPa) and stretchable (around 600%) hydrogel thin films thereafter. This supercontraction is attributed to the aligned microporous hierarchical structures of the films, which also facilitate electronic integration. We used this film to fabricate shape-adaptive electrode arrays that simplify the implantation procedure through supercontraction and conformally wrap around nerves, muscles and hearts of different sizes when wetted for in vivo nerve stimulation and electrophysiological signal recording. This study demonstrates that this water-responsive material can play an important part in shaping the next-generation tissue-electronics interfaces as well as broadening the biomedical application of shape-adaptive materials.

In vitro activity of cefiderocol, a siderophore cephalosporin, against carbapenem-resistant hypervirulent Klebsiella pneumoniae in China.

Cefiderocol is a siderophore cephalosporin that binds ferric iron and utilizes iron transporters to cross the cell membrane. Hypervirulent Klebsiella pneumoniae (hvKp) is known to produce more siderophores; in this case, the uptake of cefiderocol may be decreased. Therefore, the objective of this study was to evaluate the in vitro activity of cefiderocol against hvKp isolates. A total of 320 carbapenem-resistant K. pneumoniae (CRKp) isolates were collected in China between 2014 and 2022, including 171 carbapenem-resistant hvKp (CR-hvKp) and 149 carbapenem-resistant classical K. pneumoniae (CR-cKp). Quantitative detection of siderophores showed that the average siderophore production of CR-hvKp (234.6 mg/L) was significantly higher than that of CR-cKp (68.9 mg/L, P < 0.001). The overall cefiderocol resistance rate of CR-hvKp and CR-cKp was 5.8% (10/171) and 2.7% (4/149), respectively. The non-susceptible rates of both cefiderocol and siderophore production of CR-hvKp isolates were higher than those of CR-cKp in either NDM-1- or KPC-2-producing groups. The MIC90 and MIC50 for CR-hvKp and CR-cKp were 8 mg/L and 2 mg/L and 4 mg/L and 1 mg/L, respectively. The cumulative cefiderocol MIC distribution for CR-hvKp was significantly lower than that of CR-cKp isolates (P = 0.003). KL64 and KL47 consisted of 53.9% (83/154) and 75.7% (53/70) of the ST11 CR-hvKp and CR-cKp, respectively, and the former had significantly higher siderophore production. In summary, cefiderocol might be less effective against CR-hvKp compared with CR-cKp isolates, highlighting the need for caution regarding the prevalence of cefiderocol-resistant K. pneumoniae strains, particularly in CR-hvKp isolates.

Carbapenem-resistant Citrobacter freundii harboring blaKPC-2 and blaNDM-1: a study on their transferability and potential dissemination via generating a transferrable hybrid plasmid mediated by IS6100.

Introduction: The increase in clinical Enterobacteriaceae with dual carbapenemase has become a serious healthcare concern. It is essential to characterize the transferability and potential dissemination of blaKPC-2- and blaNDM-1-coharboring carbapenem-resistant Citrobacter freundii (CRCF). Methods: Four blaKPC-2- and blaNDM-1-coharboring CRCF strains were collected from our surveillance of the prevalence of carbapenem-resistant Enterobacteriaceae. The isolates were assessed using species identification, antimicrobial susceptibility testing, conjugation assays, whole-genome sequencing, plasmid stability, and fitness costs. Clonality, genome, plasmidome, and phylogeny were analyzed to reveal potential dissemination. Results: Three ST523 blaKPC-2- and blaNDM-1-coharboring CRCF strains, collected from the same hospital within 1 month, exhibited high homology (both identity and coverage >99%), implying clonal dissemination and a small-scale outbreak. Moreover, the blaKPC-2 and blaNDM-1 genes were coharbored on an IncR plasmid, probably generated by a blaKPC-2-harboring plasmid acquiring blaNDM-1, in these three strains. Importantly, the IncR plasmid may form a transferable hybrid plasmid, mediated by IS6100 via transposition, with another IncFII plasmid included in the same C. freundii strain. Furthermore, the blaKPC-2 and blaNDM-1 of the fourth CRCF strain are located on two different non-transferable plasmids lacking complete transfer elements. Additionally, throughout the course of the 10-day continuous passage, the genetic surroundings of blaNDM-1 in four CRCF strains were gradually excised from their plasmids after the 8th day, whereas they maintained 100% retention for blaKPC-2. Genome and plasmidome analyses revealed that blaKPC-2- or blaNDM-1-harboring C. freundii were divergent, and these plasmids have high homology to plasmids of other Enterobacteriaceae. Conclusion: Clonal dissemination of ST523 blaKPC-2- and blaNDM-1-coharboring CRCF strains was detected, and we first reported blaKPC-2 and blaNDM-1 concomitantly located on one plasmid, which could be transferred with mediation by IS6100 via transposition. Continued surveillance should urgently be implemented.

Within-host acquisition of colistin-resistance of an NDM-producing Klebsiella quasipneumoniae subsp. similipneumoniae strain through the insertion sequence-903B-mediated inactivation of mgrB gene in a lung transplant child in China.

Background: Colistin, as the antibiotic of "last resort" for carbapenem-resistant Klebsiella, develop resistance during administration of this antimicrobial agent. We identified an NDM-1-producing Klebsiella quasipneumonuae subsp. similipneumoniae (KQSS) strain KQ20605 recovered from a child, which developed resistance to colistin (KQ20786) through acquiring an IS903B element between the -27th and -26th bp of mgrB promoter region after 6-day colistin usage. Objectives: The aim of this study is to explore the source of IS903B in the disruptive mgrB gene and its underlying mechanisms. Materials and methods: Antibiotics susceptibility testing was conducted via microbroth dilution method. The in vitro colistin-induced experiment of KQ20605 was performed to mimic the in vivo transition from colistin-sensitive to resistant. Whole-genome sequencing was used to molecular identification of colistin resistance mechanism. Results: The IS903B element integrated into mgrB gene of KQ20786 had a 100% nucleotide identity and coverage match with one IS903B on plasmid IncR, and only 95.1% (1005/1057) identity to those on chromosome. In vitro, upon the pressure of colistin, KQ20605 could also switch its phenotype from colistin-sensitive to resistant with IS elements (e.g., IS903B and IS26) frequently inserted into mgrB gene at "hotspots", with the insertion site of IS903B nearly identical to that of KQ20786. Furthermore, IS26 elements in this isolate were only encoded by plasmids, including IncR and conjugative plasmid IncN harboring bla NDM. Conclusion: Mobilizable IS elements on plasmids tend to be activated and integrated into mgrB gene at "hotspots" in this KQSS, thereby causing the colistin resistance emergence and further dissemination.

Effects of ivabradine on ventricular electrophysiological remodeling after myocardial infarction in rats.

Introduction: This study aims to investigate the effects of ivabradine (IVA) on ventricular electrophysiological remodeling after myocardial infarction (MI) in rats. Material and methods: A total of 60 male Sprague-Dawley rats were randomly divided into five groups: an MI group, an IVA group, a metoprolol (MET) group, an IVA + MET group, and a sham group. After a four-week intervention, the ventricular electrophysiological parameters were detected by multichannel electrophysiological polygraph. Then, the morphological characteristics were evaluated using hematoxylin and eosin (H&E) and Masson's staining, and the expression of phosphorylated connexin 43 (p-Cx43) in the left ventricular wall was detected through immunohistochemistry and the Western blot test. Results: The electrophysiological examination revealed that the induction rate and fatality rate of ventricular tachycardia (VT)/ventricular fibrillation (VF) were lower in both the IVA and the MET group, compared with the MI group (6/12, 6/12 vs. 10/11; and 1/12, 1/12 vs. 5/11; all p < 0.05), as well as the IVA + MET group (1/11 vs. 10/11, p < 0.01; and 1/11 vs. 5/11, p < 0.05). The induction rate of VT/VF was lower in the IVA + MET group, compared to the MET group (1/11 vs. 6/12, p < 0.05). H&E and Masson's staining revealed that compared with the MI group, the left ventricular infarction area was lower in the IVA, MET, and IVA + MET groups (p < 0.05, p < 0.05, and p < 0.01, respectively), while collagen volume fraction (CVF) also was lower in the other groups (all p < 0.01). The left ventricular infarction area and CVF both were lower in the IVA + MET group, compared to the MET group (p < 0.05 and p < 0.01, respectively). The immunohistochemistry and Western blot revealed that p-Cx43 expression was higher in the treatment groups, compared with the MI group (all p < 0.01). Conclusions: IVA can reduce the incidence of ventricular arrhythmia after MI in male rats by improving both structural and electrical remodeling, and the combination of IVA and MET is even more effective.