The correlation between intestinal colonization and infection of carbapenem-resistant Klebsiella pneumoniae: a systemactic review.

As a widely spread Gram-negative bacteria, klebsiella pneumoniae mainly causes acquired infections in hospitals, such as lung infections, urinary tract infections, bloodstream infections, etc. In recent years, the number of multidrug-resistant K. pneumoniae strains has increased dramatically, posing a great threat to human health. Carbapenem-resistant Klebsiella pneumoniae (CRKP) can be colonized in human body, especially in gastrointestinal tract, and some colonized patients can be infected during hospitalization, among which invasive operation, underlying disease, admission to intensive care unit, antibiotic use, severity of the primary disease, advanced age, operation, coma and renal failure are common risk factors for secondary infection. Active screening and preventive measures can effectively prevent the occurrence of CRKP infection. Based on the epidemiological status, this study aims to discuss the correlation between colonization and secondary infection induced by carbapenem-resistant Klebsiella pneumoniae and risk factors for their happening, and provide some reference for nosocomial infection prevention and control.

Integration of single-cell RNA sequencing of endothelial cells and proteomics to unravel the role of ICAM1-PTGS2 communication in apical periodontitis: A laboratory investigation.

AIM: Endothelial cells (EDs) play a key role in angiogenesis and are associated with granulomatous lesions in patients with chronic apical periodontitis (CAP). This study aimed to investigate the diversity of EDs using single-cell ribonucleic acid sequencing (scRNA-seq) and to evaluate the regulation of intercellular adhesion molecule 1 (ICAM1) on the ferroptosis-related protein, prostaglandin-endoperoxide synthase 2 (PTGS2), in CAP. METHODOLOGY: EDs from the uploaded scRNA-seq data of five CAP samples (GSE181688 and GSE197680) were categorized using distinct marker genes. The interactions between vein EDs (veinEndo) and other cell types were analysed using CellPhoneDB. Differentially expressed proteins in the proteomics of human umbilical vein EDs (HUVECs) and THP-1-derived macrophages infected with Porphyromonas gingivalis were compared with the differentially expressed genes (DEGs) of VeinEndo in scRNA-seq of CAP versus healthy control periodontal tissues. The protein-protein interaction of ICAM1-PTGS2 in macrophages and HUVECs was validated by adding recombinant ICAM1, ICAM1 inhibitor and PTGS2 inhibitor using real-time polymerase chain reaction (PCR), western blotting, and immunofluorescence staining. RESULTS: EDs in patients with CAP were divided into eight subclusters: five vein ED, capillaries, arterials and EC (PLA). There were 29 mutually upregulated DEGs and two mutually downregulated DEGs in vein cells in the scRNA-seq data, as well as differentially expressed proteins in the proteomics of HUVECs. Real-time PCR and immunofluorescence staining showed that ICAM1 and PTGS2 were highly expressed in CAP, infected HUVECs, and macrophages. Recombinant protein ICAM1 may improve PTGS2 expression, reactive oxygen species (ROS), and Fe2+ levels and decrease glutathione peroxidase 4 (GPX4) and SLC7A11 protein levels. ICAM1 inhibitor may inverse the above changes. CONCLUSIONS: scRNA-seq revealed the diversity of EDs in CAP and identified the possible regulation of ICAM1 by the ferroptosis-related protein, PTGS2, in infected HUVECs and macrophages, thus providing a basis for therapeutic approaches that target the inflammatory microenvironment of CAP.

Chromosomal integration and plasmid fusion occurring in ST20 carbapenem-resistant Klebsiella pneumoniae isolates coharboring blaNDM-1 and blaIMP-4 induce resistance transmission and fitness variation.

To investigate the epidemiology of ST20 carbapenem-resistant Klebsiella pneumoniae (CRKP) in China, and further explore the genomic characteristics of blaIMP-4 and blaNDM-1 coharboring isolates and plasmid contributions to resistance and fitness. Seven ST20 CRKP isolates were collected nationwide, and antimicrobial susceptibility testing was performed. Antimicrobial resistance genes, virulence genes, and plasmid replicons were identified via whole-genome sequencing, and clonality assessed via core-genome multilocus sequence typing. Furthermore, we found four dual-metallo-ß-lactamases (MBL)-harbouring isolates, the gene location was detected by Southern blotting, and plasmid location analysis showed that blaIMP-4 was located on a separate plasmid, a self-conjugative fusion plasmid, or the bacterial chromosome. These isolates were subjected to long-read sequencing, the presence of blaIMP-4 in different locations was identified by genomic comparison, and transposon units were detected via inverse PCR. We subsequently found that blaIMP-4 on the fusion plasmid and bacterial chromosome was formed via intact plasmid recombination by the IS26 and ltrA, respectively, and the circular transposon unit was related to cointegration, however, blaIMP-4 in different locations did not affect the gene stability. The blaNDM-1-harbouring plasmid contributed to the increased resistance to ß-lactams and shortened survival lag time which was revealed in plasmid cured isolates. In summary, the K. pneumoniae ST20 clone is a high-risk resistant clone. With the use of ceftazidime/avibactam, MBL-positive isolates, especially dual-MBL-harbouring isolates, should be given additional attention.

PM2.5 induces renal tubular injury by activating NLRP3-mediated pyroptosis.

Fine particulate matter (PM2.5)-related health issues have received increasing attention as a worldwide public health problem, and PM2.5-related chronic kidney disease (CKD) has been emerging over the years. Limited research has focused on the mechanism of PM2.5-induced kidney disease. To investigate the impact of PM2.5 on the kidney and its potential mechanism, we generated a PM2.5-exposed C57BL/6 mouse model by using Shanghai Meteorological and Environment Animal Exposure System (Shanghai-METAS) for 12 weeks, urine, blood and kidney tissues were collected. The pathological changes and the function of the kidney were measured after PM2.5 exposure for 12 weeks. Along with glomerular damage, tubular damage was also severe in PM2.5-induced mice. The results of mRNA-seq indicate that pyroptosis is involved. Pyroptosis is defined as caspase-1-dependent programmed cell death in response to insults. The expression of the nucleotide-binding and oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3), Caspase-1, gasdermin D (GSDMD) and IL-1ß was detected. NLRP3 inflammasome activation and subsequent pyroptosis were observed in PM2.5-exposed kidney tissues and PM2.5-exposed Bumpt cells too. At the meantime, the inhibitors of NLRP3 and caspase-1 were applied to the PM2.5 exposed Bumpt cells. It turned out to have a significant rescue effect of the inhibitors. This study revealed new insights into PM2.5-induced kidney injury and specific kidney pathological damage, as well as morphological changes, and defined the important role of pyroptosis in PM2.5-induced kidney dysfunction.

PCSK9 causes inflammation and cGAS/STING pathway activation in diabetic nephropathy.

Our previous research revealed that an increase in PCSK9 is linked to aggravated inflammation in the kidneys of mice affected by a high-fat diet and streptozotocin (HFD/STZ) or in HGPA-induced HK-2 cells. Furthermore, the cGAS/STING pathway has been reported to be involved in diabetic nephropathy (DN). Therefore, in this study, we aimed to examine the correlation between the proinflammatory effect of PCSK9 and the cGAS/STING pathway in DN. We used PCSK9 mAbs to inhibit PCSK9 in vivo and PCSK9 siRNA in vitro and measured the inflammatory phenotype in HFD/STZ-treated mice or HGPA-induced HK-2 cells, and observed decreased blood urea nitrogen, creatinine, UACR, and kidney injury in response to the PCSK9 mAb in HFD/STZ-treated mice. Moreover, IL-1 ß, MCP-1, and TNF-α levels were reduced by the PCSK9 mAb in vivo and PCSK9 siRNA in vitro. We observed increased mtDNA damage and activation of the cGAS-STING signaling pathway during DN, as well as the downstream targets p-TBK1, p-NF-κB p65, and IL-1ß. In a further experiment with an HGPA-induced DN model in HK-2 cells, we revealed that mtDNA damage was increased, which led to the activation of the cGAS/STING system and its downstream targets. Notably, the cGAS-STING signaling pathway was inhibited by the PCSK9 mAb in vivo and PCSK9 siRNA in vitro. In addition, inhibition of STING with C-176 in HGPA-induced HK-2 cells markedly blocked inflammation. In conclusion, we report for the first time that PCSK9 triggers mitochondrial DNA damage and activates the cGAS-STING pathway in DN, which leads to a series of inflammation cascades. PCSK9-targeted intervention can effectively reduce DN inflammation and delay its progression. Moreover, the inhibition of STING significantly abrogated the inflammation triggered by HGPA in HK-2 cells.

Prevalence and molecular characteristics of colistin-resistant isolates among clinically isolated carbapenem-resistant Klebsiella pneumoniae in China.

Colistin resistance in carbapenem-resistant Klebsiella pneumoniae (CRKP) poses health challenges. To investigate the prevalence and molecular characteristics of colistin-resistant CRKP, 708 isolates were collected consecutively from 28 tertiary hospitals in China from 2018 to 2019, and 14 colistin-resistant CRKP were identified. Two-component systems (TCSs) related to colistin resistance (PmrA/B, PhoP/Q, and CrrA/B), the negative regulator mgrB gene and mcr genes, were analysed using genomic sequencing. The relative expression of TCSs genes along with their downstream pmrC and pmrK genes was determined using quantitative real-time PCR (qRT‒PCR). A novel point mutation in PhoQ was confirmed by site-directed mutagenesis, and the subsequent transcriptome changes were analysed by RNA sequencing (RNA-Seq). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to detect modifications in lipid A. The results showed that only one isolate carried the mcr-8.1 gene, nine exhibited MgrB inactivation or absence, and three exhibited mutations in PmrB. One novel point mutation, L247P, in PhoQ was found to lead to a 64-fold increase in the minimum inhibitory concentration (MIC) of colistin. qRT‒PCR revealed overexpression of phoP/Q and pmrK in isolates with or without MgrB inactivation, and pmrB mutation resulted in overexpression of pmrA and pmrC. Furthermore, transcriptome analysis revealed that the PhoQ L247P novel point mutation caused upregulated expression of phoP/Q and its downstream operon pmrHFIJKLM. Meanwhile, the pmrA/B regulatory pathway did not evolve colistin resistance. Mass spectrometry analysis showed the addition of 4-amino-4-deoxy-L-arabinose (L-Ara4N) to lipid A in colistin-resistant isolates with absence of MgrB. These findings illustrate that the molecular mechanisms of colistin resistance in CRKP isolates are complex, and that MgrB inactivation or absence is the predominant molecular mechanism. Interventions should be initiated to monitor and control colistin resistance.

Investigating Possible Interspecies Communication of Plasmids Associated with Transfer of Third-Generation Cephalosporin, Quinolone, and Colistin Resistance Between Simultaneously Isolated Escherichia Coli and Klebsiella Pneumoniae.

The coinfection process producing multiple species of pathogens provides a specific ecological niche for the exchange of genetic materials between pathogens, in which plasmids play a vital role in horizontal gene transfer, especially for drug resistance, but the underlying transfer pathway remains unclear. Interspecies communication of the plasmids associated with the transfer of third-generation cephalosporins, quinolones, and colistin resistance has been observed in simultaneously isolated Escherichia coli and Klebsiella pneumoniae from abdominal drainage following surgery. The MICs of antimicrobial agents were determined by the broth microdilution method. The complete chromosome and plasmid sequences were obtained by combining Illumina paired-end short reads and MinION long reads. S1-PFGE, southern blot analysis and conjugation assay confirmed the transferability of the mcr-1-harboring plasmid. Both the E. coli isolate EC15255 and K. pneumoniae isolate KP15255 from the same specimen presented multidrug resistance. Each of them harbored one chromosome and three plasmids, and two plasmids and their mediated resistance could be transferred to the recipient by conjugation. Comparison of their genome sequences suggested that several genetic communication events occurred between species, especially among their plasmids, such as whole-plasmid transfer, insertion, deletion, amplification, or inversion. Exchange of plasmids or the genetic elements they harbor plays a critical role in antimicrobial resistance gene transmission and poses a substantial threat to nosocomial infection control, necessitating the continued surveillance of multidrug resistant pathogens, especially during coinfection. IMPORTANCE The genome sequence of bacterial pathogens commonly provides a detailed clue of genetic communication among clones or even distinct species. The intestinal microecological environment is a representative ecological niche for genetic communication. However, it is still difficult to describe the details of horizontal gene transfer or other genetic events within them because the evidence in the genome sequence is incomplete and limited. In this study, the simultaneously isolated Escherichia coli and Klebsiella pneumoniae from a coinfection process provided an excellent example for observation of interspecies communication between the two genomes and the plasmids they harbor. A complete genome sequence acquired by combining the Illumina and MinION sequencing platforms facilitated the understanding of genetic communication events, such as whole-plasmid transfer, insertion, deletion, amplification, or inversion, which contribute to antimicrobial resistance gene transmission and are a substantial threat to nosocomial infection control.

Aggregated coordination polymers of Ag+ with a cysteine derivative ligand containing an AIEgen.

We investigated coordination polymers of Ag+ with a cysteine-based thiol ligand designed to contain a tetraphenylethylene AIEgen (L- and D-1). The coordination polymers, forming in a variety of protic and aprotic organic solvents, such as THF, CH3CN and CH3OH, were shown to undergo aggregation in H2O/THF binary solvents at water volume fractions above 50%, where emission was substantially enhanced while the CD profile was reversed, yet the dependence of the CD signal on ee remained S-shaped for the polymers in the aprotic organic solvents THF and CH3CN, in contrast to that in protic solvents CH3OH and C2H5OH.

Clonal outbreak of NDM-1-producing Enterobacter hormaechei belonging to high-risk international clone ST78 with the coexistence of tmexCD2-toprJ2 and mcr-9 in China.

OBJECTIVES: The emergence of carbapenem-resistant Enterobacter cloacae complex (CR-ECC) has posed significant global challenges to the clinical treatment of healthcare-associated infections. This study reports the clonal outbreak of NDM-1-producing Enterobacter hormaechei (E. hormaechei) with the coexistence of tmexCD2-toprJ2 and mcr-9 in China. METHODS: During the outbreak (January 2018 - December 2021), 15 non-repetitive multidrug-resistant E. hormaechei strains were obtained from 13 patients in a tertiary hospital. Antimicrobial susceptibility testing, plasmid stability, plasmid conjugation, plasmid fitness evaluation, colistin induction, whole-genome sequencing, and bioinformatics analysis were performed. A phylogenetic tree was constructed based on single nucleotide polymorphisms of core genomes to illustrate the evolutionary dynamics of mcr-9-carrying E. hormaechei strains worldwide. RESULTS: The 15 E. hormaechei strains belonged to the high-risk international clone ST78 and co-harboured tmexCD2-toprJ2 and blaNDM-1, of which 12 E. hormaechei strains carried the mcr-9 gene. Whole-genome sequencing analysis revealed that tmexCD2-toprJ2 and blaNDM-1 coexisted on the IncFIB/IncFII-type plasmid, which could be transferred to Escherichia coli J53 by conjugation and had a significant effect on host fitness. The mcr-9 gene was located between two insertion sequences, IS903B and IS1R, but lacked the two-component system regulatory gene qseBC, which might be the reason for all mcr-9-positive E. hormaechei strains remaining susceptible to colistin. The expression of mcr-9 was not inducible in strains confirmed by colistin induction assays. Phylogenetic analysis illustrated the silent spread and rapid evolution of mcr-9-carrying E. hormaechei worldwide. CONCLUSION: This study enriched the epidemiological and genomic characterisation of the coexistence of tmexCD2-toprJ2 and mcr-9 in ST78 CR-ECC isolates and demonstrated that they could prolong clonal dissemination in a tertiary hospital in China. Continuous epidemiological surveillance and molecular characterisation of CR-ECC should be conducted to monitor the evolution of CR-ECC around the world.

Coexposure to multiple metals and renal tubular damage: a population-based cross-sectional study in China's rural regions.

Previous studies have indicated that exposure to a single toxic metal can cause renal tubular damage, while evidence about the effects of multimetal exposure on renal tubular damage is relatively limited. We aimed to evaluate the relationships of multimetal coexposure with renal tubular damage in adults in heavy metal-polluted rural regions of China. A cross-sectional study of 1918 adults in China's heavy metal-contaminated rural regions was conducted. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to measure the plasma levels of 18 metals in participants, and immune turbidimetry was used to measure sensitive biological indicators, reflecting renal tubular damage (including retinol-binding protein and ß2-microglobulin). Least absolute shrinkage and selection operator (LASSO) penalized regression analysis, logistic and linear regression analysis, restricted cubic spline (RCS) regression analysis and the Bayesian kernel machine regression (BKMR) method were used to explore associations of multimetal coexposure with renal tubular damage risk or renal tubular damage indicators. Plasma selenium, cadmium, arsenic, and iron were identified as the main plasma metals associated with renal tubular damage risk after dimensionality reduction. Multimetal regression models showed that selenium was positively associated, and iron was negatively associated with renal tubular damage risk or its biological indicators. Multimetal RCS analyses additionally revealed a non-linear relationship of selenium with renal tubular damage risk. The BKMR models showed that the metal mixtures were positively associated with biological indicators of renal tubular damage when the metal mixtures were above the 50th percentile of concentration. Our findings indicated that natural exposure to high levels of multimetal mixtures increases the risk of renal tubular damage. Under the conditions of multimetal exposure, selenium was positively associated, and iron was negatively associated with renal tubular damage risk or its biological indicators.

Emergence of coexistence of a novel blaNDM-5-harbouring IncI1-I plasmid and an mcr-1.1-harbouring IncHI2 plasmid in a clinical Escherichia coli isolate in China.

BACKGROUND: Co-harbouring of carbapenem and colistin resistance genes in multidrug-resistant Enterobacterales strains poses a serious public health problem. In this study, an MCR-1.1 and NDM-5 coproducing Escherichia coli strain named EC6563 was isolated and characterized. OBJECTIVES: This study aimed to characterize a clinical carbapenem-resistant E. coli isolate which co-harbours mcr-1.1 and blaNDM-5 on separate plasmids, and explored the phenotypic and genotypic characteristics of the mcr-1.1- and blaNDM-5-harbouring plasmids. METHODS: E. coli isolate EC6563 was subjected to antimicrobial susceptibility testing, conjugation assay, stability of the plasmid and growth rate determination. In addition, the whole genome sequence of this strain was obtained and the genetic characteristics of the mcr-1.1- and blaNDM-5-harbouring plasmids were analyzed. RESULTS: Carbapenem-resistant E. coli isolate EC6563 was resistant to all the tested antibiotics except tigecycline. Bioinformatic analysis confirmed that the IncHI2 plasmid carrying mcr-1.1 was highly similar to the previously reported mcr-1.1-harbouring plasmid pGDP37-4, and carried multiple drug resistance genes and the IncI1-I plasmid carrying blaNDM-5 had low similarity to the published blaNDM-5-carrying IncI1-I plasmid pEC-16-10-NDM-5. The pEC6563-NDM5 plasmid was capable of conjugation with an efficiency of 1.34 × 10-2 in a filter mating experiment. The transconjugant J53/pEC6563-NDM5 was able to be stably inherited after 12 days of passage. CONCLUSIONS: To the best of our knowledge, this is the first time that an IncHI2 plasmid carrying mcr-1.1 and an IncI1-I plasmid carrying blaNDM-5 is found to coexist in an E. coli isolate. Our research expands the known diversity of plasmids in NDM-5-producing Enterobacterales strains. Meanwhile, effective measures should be taken to prevent the spread of these plasmids.

The practicability of different preparation of mandibular molar restored by modified endocrown with intracanal extension: Computational analysis using finite element models.

BACKGROUND AND OBJECTIVE: Post-core-crown (PCC) and endocrown are two common restorative methods for severely damaged molars, but exhibit disadvantages. This study aimed to explore the practicability of modified endocrown with a 2 mm intracanal extension (MED) to restore defective teeth using finite element analysis (FEA). METHODS: Five groups of numerical models of mandibular molars restored by three MEDs, a PCC, and a routine endocrown after root canal treatment were devised by FEA software. We constructed 4 mm, 3 mm, and 2 mm thickness of MED restorations to restore mandibular molars that were prepared to 1 mm, 2 mm, and 3 mm from the cemento-enamel junction (CEJ). Furthermore, PCC and routine endocrown were used to compare the stress distribution with MED. Lithium disilicate glass-ceramics (EMAX) and resin nanoceramics (LU) were considered restorative materials, and a vertical load of 600 N and an oblique load of 200 N were applied to the restorations. RESULTS: In three MEDs by LU, 2 mm thickness of restoration generated the highest stress on prepared teeth, while the thickness of EMAX did not significantly influence the stress value. MED by LU generated higher stress around the CEJ, and reduced the stress on the middle and lower root compared to MEDs by EMAX, PCC by EMAX, and PCC by LU. MED by EMAX caused lower stress around the CEJ, and generated higher stress in the chamber walls after extended root canals compared with MED by LU, endocrowns by LU, and endocrowns by EMAX. There was an evident stress concentration at the last but one layer, which was a thin area of the tooth root in all restorative models. CONCLUSIONS: The use of modified endocrown may be considered an effective restorative method to restore defective mandibular molar, but suitable restorative material must be selected based on the tooth preparation method and deficiencies in the tooth structure.

Single-cell RNA analysis of chemokine expression in heterogeneous CD14+ monocytes with lipopolysaccharide-induced bone resorption.

Lipopolysaccharide (LPS)-induced bone resorption has normally been found in inflammatory bone diseases, but the underlying mechanism is currently unclear. Since LPS binds to CD14 and activates Toll-like receptor 4 (TLR4) in monocytes, the present study focused on CD14+ monocytes and observed their responses after LPS treatment during the progression of local bone destruction. CD14+ monocytes were obtained from human peripheral blood mononuclear cells (PBMCs) by magnetic cell separation (MACS), and their classification was confirmed by fluorescence-activated cell sorting (FACS). Single-cell RNA sequencing (scRNA-seq) was further utilized to analyze their subpopulations, and the results showed that physiological CD14+ monocytes were heterogeneous and divided into 6 subsets, that could be easily agitated. After priming with a suitable concentration of LPS, heterogeneous CD14+ monocytes became pathological and expressed a large number of chemokines as a "cascade effect". Some of these chemokines have been validated in an animal model of mouse calvarial bone invasion. Taken together, our research has linked enhanced chemokine expression with stimulation of heterogeneous CD14+ monocytes, and indicated that inflammatory responses caused by microbiome infection are responsible for the recruitment and mobilization of CD14+ monocytes into bone resorption sites, which may explain the pathogenesis of LPS-associated bone diseases.

Epidemiological Characteristics of OXA-232-Producing Carbapenem-Resistant Klebsiella pneumoniae Strains Isolated during Nosocomial Clonal Spread Associated with Environmental Colonization.

Here, a program was designed to surveil the colonization and associated infection of OXA-232-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) (OXA-232-CRKP) in an intensive care unit (ICU) and to describe the epidemiological characteristics during surveillance. Samples were sourced from patient and environment colonization sites in the ICU from August to December 2019. During the surveillance, 106 OXA-232-CRKP strains were isolated from 8,656 samples of colonization sites, with an average positive rate of 1.22%. The rate from patient colonization sites was 3.59% (60/1,672 samples), over 5 times higher than that of the environment (0.66% [46/6,984 samples]). Rectal swabs and ventilator-related sites had the highest positive rates among patient and environment colonization sites, respectively. Six of the 15 patients who had OXA-232-CRKP at colonization sites suffered from OXA-232-CRKP-related infections. Patients could obtain OXA-232-CRKP from the environment, while long-term patient colonization was mostly accompanied by environmental colonization with subsequent infection. Antimicrobial susceptibility testing presented similar resistance profiles, in which all isolates were resistant to ertapenem but showed different levels of resistance to meropenem and imipenem. Whole-genome sequencing and single-nucleotide polymorphism (SNP) analysis suggested that all OXA-232-CRKP isolates belonged to the sequence type 15 (ST15) clone and were divided into two clades with 0 to 45 SNPs, sharing similar resistance genes, virulence genes, and plasmid types, indicating that the wide dissemination of OXA-232-CRKP between the environment and patients was due to clonal spread. The strains all contained ß-lactam resistance genes, including blaOXA-232, blaCTX-M-15, and blaSHV-106, and 75.21% additionally carried blaTEM-1. In brief, wide ST15 clonal spread and long-term colonization of OXA-232-CRKP between patients and the environment were observed, with microevolution and subsequent infection. IMPORTANCE OXA-232 is a variant of OXA-48 carbapenemase, which has been increasingly reported in nosocomial outbreaks in ICUs. However, the OXA-232-CRKP transmission relationship between the environment and patients in ICUs was still not clear. Our study demonstrated the long-term colonization of OXA-232-CRKP in the ICU environment, declared that the colonization was a potential risk to ICU patients, and revealed the possible threat that this OXA-232-CRKP clone would bring to public health. The wide dissemination of OXA-232-CRKP between the environment and patients was due to ST15 clonal spread, which presented a multidrug-resistant profile and carried disinfectant resistance genes and virulence clusters, posing a challenge to infection control. The study provided a basis for environmental disinfection, including revealing common environmental colonization sites of OXA-232-CRKP and suggesting appropriate usage of disinfectants to prevent the development of disinfectant resistance.

Probiotics improve renal function, glucose, lipids, inflammation and oxidative stress in diabetic kidney disease: a systematic review and meta-analysis.

AIMS: The role of probiotics in the management of diabetic kidney disease (DKD) has been shown. Several current trials are investigating the effect of probiotics, which are widely used to modulate biomarkers of renal function, glucose, lipids, inflammation and oxidative stress in patients with DKD. However, their findings are controversial. This study aimed to systematically evaluate the impact of probiotics on patients with DKD via meta-analysis. METHODS: PubMed, The Cochrane Library, Web of Science, Scopus, Embase, China National Knowledge Infrastructure, Chinese Wanfang Database and Chinese VIP Database were searched for relevant studies from the establishment of these databases to September 2021. The pooled results evaluated the impact of probiotics on renal function, glucose, lipids, inflammation and oxidative stress indicators in patients with DKD. Additionally, subgroup analysis was performed based on intervention duration, probiotic dose and probiotic consumption patterns, respectively. RESULTS: Ten trials that included 552 participants were identified for analysis. Compared with the controls, probiotics significantly decreased serum creatinine (Scr) [WMD = -0.17 mg/dL; 95%CI = -0.29, -0.05; p = 0.004], blood urea nitrogen (BUN) [WMD = -1.36 mg/dL; 95%CI = -2.20, -0.52; p = 0.001], cystatin C (Cys C) [WMD = -29.50 ng/mL; 95%CI = -32.82, -26.18; p < 0.00001], urinary albumin/creatinine ratio (UACR) [WMD = -16.05 mg/g; 95%CI = -27.12, -4.99; p = 0.004] and natrium (Na) [WMD = -0.94 mmol/L; 95%CI = -1.82, -0.05; p = 0.04] in patients with DKD. Enhanced glycemic control was observed in patients with DKD receiving probiotics compared with controls, as demonstrated by reduced levels of fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), homeostasis model of assessment-estimated insulin resistance (HOMA-IR), and increased quantitative insulin sensitivity check index (QUICKI). Probiotics affected lipid metabolism parameters with decreasing triglycerides (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c) levels in patients with DKD. Probiotics could also could improve inflammation and oxidative stress by decreasing high-sensitivity C-reactive protein (hs-CRP), plasma malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione (GSH) and nitric oxide (NO). Additionally, subgroup analysis showed that those who received multiple species probiotics had a statistically significant difference in BUN, FPG, HOMA-IR, high-density lipoprotein cholesterol (HDL-c), MDA, TAC, and NO. Meanwhile, Scr, LDL-c, HDL-c, MDA, and TAC were ameliorated when the intervention duration was more than eight weeks and BUN, FPG, HOMA-IR, and MDA were improved when the probiotic dose was greater than four billion CFU/day. CONCLUSIONS: Our analysis revealed that probiotics could delay the progression of renal function injury, improve glucose and lipid metabolism, and reduce inflammation and oxidative stress in patients with DKD. Subgroup analysis showed that intervention duration, probiotic dose and probiotic consumption patterns had an effect of probiotics on outcomes.

High prevalence of colistin resistance and mcr-9/10 genes in Enterobacter spp. in a tertiary hospital over a decade.

Enterobacter spp. are members of the 'ESKAPE' group of pathogens, which which are recognised as the leading cause of multidrug-resistant (MDR) hospital-acquired infections. Colistin is usually regarded as a last-line therapeutic option for MDR Gram-negative bacilli infections. However, colistin-resistant Enterobacter spp. have emerged in the last decade. Here we investigated the prevalence of colistin resistance and mcr genes in Enterobacter spp. of clinical origin between 2011 and 2020 in a tertiary hospital in China. Colistin resistance rates ranged between 17.1% and 34.5%, with an overall prevalence of 22.2% (190/854). No mcr-1 to mcr-8 genes were identified in the colistin-resistant Enterobacter spp. isolates, while mcr-9 and mcr-10 were detected at rates of 8.4% (16/190) and 12.6% (24/190), respectively. All of the mcr-9/10-positive Enterobacter isolates belonged to the Enterobacter cloacae complex (ECC). Meanwhile, 14.8% (98/664) and 6.0% (40/664) of non-colistin-resistant Enterobacter spp. isolates carried mcr-9 and mcr-10 genes, respectively. For the 40 mcr-9/10-positive colistin-resistant ECC isolates, mcr-9-positive ECC isolates usually co-produced extended-spectrum ß-lactamases (ESBLs) or carbapenemases, while mcr-10-positive ECC isolates produced neither. Most mcr-9/10 genes were located on plasmids. The backbone of mcr-9-harbouring plasmids was conserved, while that of mcr-10-harbouring plasmids was diverse. Our findings revealed a high prevalence of colistin resistance and a silent distribution of mcr-9/10 genes in clinical Enterobacter spp. isolates in China. It is urgent to take steps and interventions to control the prevalence of colistin resistance and prevent the dissemination of mcr-9/10 genes.

Prevalence and Characteristics of Ceftriaxone-Resistant Salmonella in Children's Hospital in Hangzhou, China.

The non-Typhi Salmonella (NTS) infection is critical to children's health, and the ceftriaxone is the important empirical treatment choice. With the increase resistance rate of ceftriaxone in Salmonella, the molecular epidemiology and resistance mechanism of ceftriaxone-resistant Salmonella needs to be studied. From July 2019 to July 2020, a total of 205 NTS isolates were collected, 195 of which (95.1%) were cultured from stool, but 10 isolates were isolated from an extraintestinal site. Serogroup B accounted for the vast majority (137/205) among the isolates. Fifty-three isolates were resistant to ceftriaxone, and 50 were isolated from children younger than 4years of age. The resistance rates for ceftriaxone, ciprofloxacin, and levofloxacin were significantly higher in younger children than the older children. The resistance genes in the ceftriaxone-susceptible isolates were detected by PCR, and ceftriaxone-resistant Salmonella were selected for further whole-genome sequencing. Whole-genome analysis showed that serotype Typhimurium and its monophasic variant was the most prevalent in ceftriaxone-resistant isolates (37/53), which comprised ST34 (33/53), ST19 (2/53), and ST99 (2/53), and they were close related in the phylogenetic tree. However, the other isolates were diverse, which included one Enteritidis (ST11), one Indiana (ST17), one Derby (ST40), four Kentucky (ST198), two Goldcoast (ST2529, ST358), one Muenster (ST321), one Virchow (ST359), one Rissen (ST469), one Kedougou (ST1543), two Uganda (ST684), and one Kottbus (ST8839). Moreover, CTX-M-55 ESBLs production (33/53) was found to be mainly responsible for ceftriaxone resistance, followed by bla CTX-M-65 (12/53), bla CTX-M-14 (4/53), bla CTX-M-9 (2/53), bla CTX-M-64 (1/53), bla CTX-M-130 (1/53), and bla CMY-2 (1/53). ISEcp1, IS903B, IS Kpn26, IS1F, and IS26 were connected to antimicrobial resistance genes transfer. In conclusion, the dissemination of ESBL-producing Salmonella isolates resulted in an increased prevalence of ceftriaxone resistance in young children. The high rate of multidrug resistance should be given additional attention.

Emergence of Ceftazidime/Avibactam and Tigecycline Resistance in Carbapenem-Resistant Klebsiella pneumoniae Due to In-Host Microevolution.

Klebsiella pneumoniae can cause both hospital- and community-acquired clinical infections. Last-line antibiotics against carbapenem-resistant K. pneumoniae (CRKP), such as ceftazidime/avibactam (CZA) and tigecycline (TGC), remain limited as treatment choices. This study aimed to investigate the mechanisms by which CRKP acquires CZA and TGC resistance in vivo under ß-lactam antibiotic and TGC exposure. Three CRKP strains (XDX16, XDX31 and XDX51) were consecutively isolated from an inpatient with a urinary tract infection in two months. PFGE and MLST showed that these strains were closely related and belonged to sequence type (ST) 4496, which is a novel ST closely related to ST11. Compared to XDX16 and XDX31, XDX51 developed CZA and TGC resistance. Sequencing showed that double copies of blaKPC-2 were located on a 108 kb IncFII plasmid, increasing blaKPC-2 expression in XDX51. In addition, ramR was interrupted by Insertion sequence (IS) Kpn14 in XDX51, with this strain exhibiting upregulation of ramA, acrA and acrB expression compared with XDX16 and XDX31. Furthermore, LPS analysis suggested that the O-antigen in XDX51 was defective due to ISKpn26 insertion in the rhamnosyl transferase gene wbbL, which slightly reduced TGC susceptibility. In brief, CZA resistance was caused mainly by blaKPC-2 duplication, and TGC resistance was caused by ramR inactivation with additional LPS changes due to IS element insertion in wbbL. Notably, CRKP developed TGC and CZA resistance within one month under TGC and ß-lactam treatment without exposure to CZA. The CRKP clone ST4496 has the ability to evolve CZA and TGC resistance rapidly, posing a potential threat to inpatients during antibiotic treatment.

Emergence of a KPC Variant Conferring Resistance to Ceftazidime-Avibactam in a Widespread ST11 Carbapenem-Resistant Klebsiella pneumoniae Clone in China.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection poses a great threat to public health worldwide, and KPC-2-producing strains are the main factors responsible for resistance to carbapenems in China. Ceftazidime/avibactam (CZA) is a novel ß-lactam/ß-lactamase inhibitor combination with good activity against KPC-2 carbapenemase and is becoming the most important option for treating KPC-producing CRKP infection. Here, we report the emergence of a novel KPC-2 variant, designated KPC-74, produced by K. pneumoniae strain KP55, that conferred CZA resistance in a patient after CZA exposure. The novel bla KPC-74 variant showed a deletion of 6 nucleotides at positions 712-717 compared with bla KPC-2, and this deletion resulted in the consequent deletion of glycine and valine at positions 239 and 240. Antimicrobial susceptibility testing showed that KP55 presents multidrug resistance, including resistance to CZA and ertapenem, but is susceptible to imipenem, meropenem, and colistin. The bla KPC-74 gene was located on a plasmid, as determined by S1-nuclease pulsed-field gel electrophoresis followed by southern blotting, and confirmed to be 133,766 bp in length by whole-genome sequencing on both the Illumina and MinION platforms. The CZA resistance phenotype of the novel KPC variant was confirmed by both transformation of the bla KPC-74-harboring plasmid and a bla KPC-74 gene cloning assay, showing a 64-fold higher CZA minimum inhibitory concentration (MIC) than the recipient strains. The G239_V240del observed in KPC-74 was outside the omega-loop region but was still close to the active site Ser70 and omega-loop in the protein tertiary structure. The enzyme kinetic parameters and IC50 values further indicated that the hydrolytic activity of the KPC-74 enzyme against ceftazidime was potentiated twofold and that the affinity between KPC-74 and avibactam was alleviated 17-fold compared with that of the KPC-2 allele. This CZA resistance mediated by KPC-74 could be selected after CZA therapy and evolved to be more diverse and heterogeneous. Surveillance of CZA resistance is urgently needed in clinical settings.

The Emergence of Novel Sequence Type Strains Reveals an Evolutionary Process of Intraspecies Clone Shifting in ICU-Spreading Carbapenem-Resistant Klebsiella pneumoniae.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an urgent public health problem worldwide, and its rapid evolution in the clinical environment has been a major concern. A total of 99 CRKP isolates spreading in the intensive care unit (ICU) setting were included and subjected to whole-genome sequencing, and their sequence types (STs), serotype loci, and virulence determinants were screened based on genome data. The phylogenetic structure was reconstructed based on the core genome multilocus sequence typing method. Regions of recombination were assessed. Biofilm formation, serum resistance assays, and a Galleria mellonella infection model were used to evaluate strain virulence. A novel ST, designated ST4496, emerged in the ICU and spread for 6 months before its disappearance. ST4496 was closely related to ST11, with only a single-allele variant, and ST11 is the most dominant clinical clone in China. Recombination events occurred at capsule biosynthesis loci and divided the strains of ST11 and its derivative ST4496 into three clusters, including ST11-KL47, ST11-KL64, and ST4496-KL47. The phylogenetic structure indicated that ST11-KL47 was probably the origin of ST11-related strain evolution and presented more diversity in terms of both sequence similarity and phenotypes. ST4496-KL47 cluster strains presented less virulence than ST11-KL64, which was probably one of the factors preventing the former from spreading widely. In conclusion, ST4496-KL47 was probably derived from ST11-KL47 via intraspecies shifting but was less competitive than ST11-KL64, which also evolved from ST11-KL47 and developed increased virulence via capsule biosynthesis locus recombination. ST11-KL64 has the potential to be the predominant CRKP clone in China.