Carbapenem-resistant Klebsiella pneumoniae (CRKP) seriously threaten the efficacy of modern medicine with a high associated mortality rate and unprecedented transmission rate. In this study, we isolated a clinical K. pneumoniae strain DY1928 harboring blaNDM-1 from a neonate with blood infection. Antimicrobial susceptibility testing indicated that DY1928 was resistant to various antimicrobial agents, including meropenem, imipenem, ceftriaxone, cefotaxime, ceftazidime, cefepime, piperacillin-tazobactam, and amoxicillin-clavulanate. S1 nuclease-pulsed field gel electrophoresis (S1-PFGE), southern blot and conjugation experiment revealed that the blaNDM-1 gene was located on a conjugative plasmid of IncA/C2 type with a 147.9 kb length. Whole-genome sequencing showed that there was a conservative structure sequence (blaNDM-1-ble-trpF-dsbD) located downstream of the blaNDM-1 gene. Multilocus sequence typing (MLST) classified DY1928 as ST25, which was a hypervirulent K. pneumoniae type. Phylogenetic analysis of genomic data from all ST25 K. pneumoniae strains available in the NCBI database suggested that all blaNDM-1 positive strains were isolated in China and had clinical origins. A mouse bloodstream infection model was constructed to test the virulence of DY1928, and 11 K. pneumoniae strains homologous to DY1928 were isolated from the feces of infected mice. Moreover, we found that DY1928 had a tendency to flow from the blood into the intestine in mice and caused multiple organ damage. To our knowledge, this is the first study to report an infection caused by blaNDM-1-positive ST25 K. pneumoniae in the neonatal unit. Our findings indicated that stricter surveillance and more effective actions were needed to reduce the risk of disseminating such K. pneumoniae strains in clinical settings, especially in neonatal wards.

Emerging mobile colistin resistance ( mcr ) genes pose a significant threat to public health for colistin was used as the last resort to treat multidrug-resistant (MDR) pathogenic bacterial infections. Hypervirulent Klebsiella pneumoniae (hvKP) is a clinically significant pathogen resulting in highly invasive infections, often complicated by devastating dissemination. Worryingly, the untreatable and severe infections caused by mcr -harbouring hvKP leave the selection of antibiotics for clinical anti-infective treatment in a dilemma. Herein, we screened 3,461 isolates from a tertiary teaching hospital from November 2018 to March 2021, and an mcr-8.2 -harbouring hvKP FAHZZU2591 with a conjugative plasmid was identified from paediatric sepsis. This is the first report of MCR-8-producing hvKP from paediatric sepsis to our best knowledge. The susceptibility, genetic features, and plasmid profiles of the isolate were investigated. Further, we assessed the virulence potential of FAHZZU2591 and verified its pathogenicity and invasive capacity using a mouse model. The phylogenetic analysis of mcr-8 -bearing K. pneumoniae revealed that China is the predominant reservoir of the mcr-8 gene, and the clinic is the primary source. Our work highlights the risk for the spread of mcr -positive hvKP in clinical, especially in paediatric sepsis, and the persistent surveillance of colistin-resistance hvKP is urgent.

Background Despite the global prevalence of Klebsiella pneumoniae Carbapenemase (KPC)-type class A β-lactamases, occurrences of KPC-3-producing isolates in China remain infrequent. This study aims to explore the emergence, antibiotic resistance profiles, and plasmid characteristics of blaKPC-3-carrying Pseudomonas aeruginosa. Methods Species identification was performed by MALDI-TOF-MS, and antimicrobial resistance genes (ARGs) were identified by polymerase chain reaction (PCR). The characteristics of the target strain were detected by whole-genome sequencing (WGS) and antimicrobial susceptibility testing (AST). Plasmids were analyzed by S1-nuclease pulsed-field gel electrophoresis(S1-PFGE), Southern blotting and transconjugation experiment. Results Five P. aeruginosa strains carrying blaKPC-3 were isolated from two Chinese patients without a history of travelling to endemic areas. All strains belonged to the novel sequence type ST1076. The blaKPC-3 was carried on a 395-kb IncP-2 megaplasmid with a conserved structure (IS6100-ISKpn27-blaKPC-3-ISKpn6-korC-klcA), and this genetic sequence was identical to many plasmid-encoded KPC of Pseudomonas species. By further analyzing the genetic context, it was supposed that the original of blaKPC-3 in our work was a series of mutation of blaKPC-2. Conclusions The emergence of a multidrug resistance IncP-2 megaplasmid and clonal transmission of blaKPC-3-producing P. aeruginosa in China underlined the crucial need for continuous monitoring of blaKPC-3 for prevention and control of its further dissemination in China.

The frequent and inappropriate use of antibiotics has caused a dramatic rise in the number, species, and degree of multi-drug resistant bacteria, making them more prevalent and difficult to treat. In this context, the aim of the present study was to characterize the OXA-484-producing strains isolated from a perianal swab of a patient by using whole-genome analysis. Patients and Methods: In this study, carbapenemase-producing Klebsiella variicola was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), average nucleotide identity (ANI) and PCR. S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting were utilized to characterize the plasmid profiles of K. variicola 4717. In particular, WGS was performed to obtain genomic information on this clinical isolate, and assemble all the plasmids of the bla OXA-484 -harboring strain. Results: The antimicrobial susceptibility pattern of K. variicola 4717 revealed that it was resistant to a range of antibiotics, including aztreonam, imipenem, meropenem, ceftriaxone, cefotaxime, ceftazidime, levofloxacin, ciprofloxacin, piperacillin-tazobactam, methylenesulfamer oxazole, amoxicillin-clavulanic acid, cefepime, and tigecycline. Its susceptibility to chloromycin was intermediate, while it was still susceptible to amikacin, gentamicin, fosfomycin, and polymyxin B. The presence of two companion plasmids, p4717_1 and p4717_2, together with a plasmid carrying the bla OXA-484 gene was observed. An in-depth investigation of p4717-OXA-484 uncovered that it is an IncX3-type plasmid and shares a similar segment encoded by IS26. Given the similar genetic background, it was conceivable that bla OXA-484 could have developed from bla OXA-181 through a series of mutations. Conclusion: Herein, we described the first genome sequence of K. variicola strain harbouring the class D β-actamase bla OXA-484 in an Inc-X3-type plasmid. Our work also uncovered the genetic characterization of K. variicola 4717 and the importance of initiating antimicrobial detection promptly.

This study aimed to investigate the mechanism and partial material basis of Jieduquyuziyin prescription (JQZP) reduces systemic lupus erythematosus (SLE) inflammation via regulating Nek7-NLRP3 signaling pathway. The therapeutic effect of JQZP was evaluated by MRL/lpr SLE mice model in vivo and Lipopolysaccharide (LPS)-induced RAW264.7 macrophage inflammation model in vitro. The partial material basis of JQZP was analyzed by network pharmacology, molecular docking and HPLC. The effect of JQZP on inhibiting the Nek7-NLRP3 signaling pathway and the underlying molecular mechanism were investigated by ELISA, RT-qPCR and Western blot. in vivo experiments showed that JQZP could ameliorate renal histopathological changes, decrease spleen index, 24 h urine and urine creatinine (UCR) concentration, and increase urinary microalbumin (ALB) concentration and microalbumin/creatinine ratio (ACR) in MRL/lpr mice. In addition, JQZP down-regulated the levels of pro-inflammatory cytokines IL-18 and IL-1β both in vivo and in vitro. Network pharmacology and HPLC analysis showed that salidroside, luteolin and apigenin in JQZP-medicated serum were partial main active ingredients, and molecular docking showed that all three main active ingredients could bind to Nek7, NLRP3 and ASC well. Western blot further confirmed that JQZP, JQZP-medicated serum and active monomer ingredients could regulate the expression of Nek7, NLRP3, and ASC in Nek7-NLRP3 signaling pathway. JQZP has a certain effect on improving excessive inflammation of SLE, and the mechanism of action may be related to the inhibition of Nek7-NLRP3 signaling pathway. Salidroside, luteolin and apigenin may be partial material basis for exerting this effect.

The emergence of carbapenemase significantly threatens public health. It is prevalent worldwide but rare in Aeromonas caviae. Unlike most bacterial species, A. caviae has two distinct flagella systems, which are closely related to biofilm formation. The ability to form biofilms on host tissues or inert surfaces constitutes an important cause of many persistent infections, which causes difficulties in clinical treatment. Here, we report on a multidrug-resistant (MDR) A. caviae carrying blaNDM–1 with a novel sequence type 1,416. The strong ability of biofilm formation of FAHZZU2447 was verified by a crystal violet assay. The resistome profile and location of the blaNDM–1 gene were determined by antimicrobial susceptibility testing, S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), and Southern blot analysis. Moreover, the strain underwent whole-genome sequencing to identify its genomic characteristics. In addition, the blaNDM–1 gene was located on a ∼243 kb plasmid with genetic context IS1R-blaNDM–1-ble-trpF-dsbD-hp-sul1-qacE. Phylogenetic analysis indicated the transmission of A. caviae in China, Japan, and Thailand. Our study aimed to elucidate the genomic features of blaNDM–1-producing A. caviae, thereby clarifying the distribution of A. caviae worldwide and emphasizing the harmfulness of biofilm formation to the clinic. Further comprehensive surveillance of this species is needed to control further dissemination.

Objective. To clarify the significance of hyaluronidsase 1 (Hyal1) expression in colorectal carcinoma (CRC) and its impact on tumor cell migration and invasiveness. Methods. Human CRC cell lines SW480, HCT116, and SW620 were purchased, ELISA and western blot were used to detect the expression of Hyal1 in cells, CCK-8 assay to detect cell proliferation ability, cell scratch assay to check cell migration rate, and cell invasion was detected by the transwell assay. The correlation of Hyal1 with CRC cell migration and invasiveness capacities was analyzed. Result. ELISA results showed that supernatant Hyal1 level was the lowest in SW480, highest in HCT116, with the level in SW620 in between ( P < 0.05 ). No evident difference was identified by western blot in Hyal1 protein expression among the three cells ( P > 0.05 ). The cell scratch assay and transwell assay showed that the migration and invasion ability of HCT116 cells was higher than that of SW620 ( P < 0.05 ). In vitro, Hyal1 had a synergistic relationship with the invasiveness and migration capacities of CRC cells ( P < 0.05 ). Conclusion. Hyal1 is elevated in CRC and is consistent with the invasiveness and metastasis abilities of CRC cells. It is hoped that this research can provide reference for future prevention and treatment of CRC.

Background: Although Klebsiella pneumoniae Carbapenemase (KPC) -type class A β-lactamases spread widely throughout the world, KPC-3-producing isolates are rarely reported in China. This study aims to explore the emergence, antibiotic resistance profiles, and plasmid characteristics of blaKPC-3-carrying Pseudomonas aeruginosa. Methods: Species identification was performed by MALDI-TOF-MS, and antimicrobial resistance genes (ARGs) were identified by polymerase chain reaction (PCR). The characteristics of the target strain were detected by whole-genome sequencing (WGS) and antimicrobial susceptibility testing (AST). Plasmids were analyzed by S1-nuclease pulsed-field gel electrophoresis(S1-PFGE), Southern blotting and transconjugation experiment. Results: Five P. aeruginosa strains carrying blaKPC-3 were isolated from two Chinese patients without a history of travelling to endemic areas. All strains belonged to the novel sequence type ST1076. The blaKPC-3 was carried on a 395-kb IncP-2 megaplasmid with a conserved structure (IS6100-ISKpn27-blaKPC-3-ISKpn6-korC-klcA), and this genetic sequence was identical to many plasmid-encoded KPC of Pseudomonas species. By further analyzing the genetic context, it was supposed that the original of blaKPC-3 in our work was a series of mutation of blaKPC-2. Conclusions: The emergence of a multidrug resistance IncP-2 megaplasmid and clonal transmission of blaKPC-3-producing P. aeruginosa in China underlined the crucial need for continuous monitoring of blaKPC-3 for prevention and control of its further dissemination in China.