Neuromedin U and neurotensin may promote the development of the tumour microenvironment in neuroblastoma.

Stage 4S neuroblastoma, as defined by the International Neuroblastoma Staging System committee (INSS), is known to regress spontaneously and have a more favourable outcome compared with stage 4 tumours. Comparing the molecular differences between these two stages may provide insights into the progression of neuroblastoma. Our study aimed to explore the molecular differences in the tumour microenvironment (TME) between INSS stage 4S and stage 4 tumours to provide an insight into the mechanisms underlying the biological processes of neuroblastoma. We downloaded the datasets GSE120572 and GSE73517 from the GEO database and pre-processed them using the limma package. CIBERSORT deconvolution agorithm was applied to analyse the differences in 22 infiltrating immune leukocyte subsets between the two stages. We used gene ontology (GO) enrichment analysis to determine the biological process (BP) annotation of differentially expressed genes (DEGs) using the online WebGestalt tool. Hub genes were determined in the STRING database and Cytoscape, and the expression of these genes was verified in the Oncomine database. Then these critical genes were performed survival analysis in TARGET database. We further validated the hub genes using a transwell assay and wound healing assay to detect the function of the genes in the neuroblastoma cell line SK-N-BE(2). GO analysis revealed that the 216 DEGs between stage 4S and stage 4 were enriched in aggressive biological processes. Neuromedin U (NMU) and neurotensin (NTS), which were significantly associated with patients' overall survival rate, were verified to be elevated in stage 4, and to promote the proliferation and invasion of the SK-N-BE(2) cell. Tumour infiltrating leukocyte analysis showed a high infiltration of regulatory T cells and type 2 tumour-associated macrophages in stage 4 but not in stage 4S. Results of gene co-expression correlation, and the results of previous studies, suggest that NMU and NTS may play certain roles in modulating TME, thus facilitating the progression of neuroblastoma.

A 2-step algorithm combining glutamate dehydrogenase and nucleic acid amplification tests for the detection of Clostridioides difficile in stool specimens.

The optimized diagnosis algorithm of Clostridioides difficile infection (CDI) is worldwide concerns. The purpose of this study was to assess the toxigenic C. difficile test performance and propose an optimal laboratory workflow for the diagnosis of CDI in mild virulent epidemic areas. Diarrhea samples collected from patients were analyzed by glutamate dehydrogenase (GDH), toxin AB (CDAB), and nucleic acid amplification test (NAAT). We assessed the performance of GDH, the GDH-CDAB algorithm, and the GDH-NAAT algorithm using toxigenic culture (TC) as a reference method. In this study, 186 diarrhea samples were collected. The numbers of TC-positive and TC-negative samples were 39 and 147, respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and kappa of the GDH assay were 100%, 80.3%, 57.4%, 100%, and 0.63; of the GDH-CDAB algorithm were 48.7%, 97.3%, 82.6%, 87.7%, and 0.54; and of the GDH-NAAT algorithm were 74.4%, 100%, 100%, 93.6%, and 0.82, respectively. The GDH-NAAT algorithm has great concordance with TC in detecting toxigenic C. difficile (kappa = 0.82), while the sensitivity of the GDH-CDAB algorithm was too low to meet the demand of CDI diagnosis clinically. GDH-NAAT algorithm is recommended for the detection of toxigenic C. difficile with high specificity, increased sensitivity, and cost-effective.

Characterization Of bla NDM-5-Positive Escherichia coli Prevalent In A University Hospital In Eastern China.

PURPOSE: The emergence and spread of carbapenem-resistant Enterobacteriaceae deserves special concern worldwide. Unlike the epidemiological characteristics reported in other studies, we found that the production of New Delhi metallo-ß-lactamase 5 was the main mechanism for the resistance of Escherichia coli to carbapenems. METHODS: All carbapenem-resistant strains were collected from July 2017 to July 2018 of the First Affiliated Hospital of Nanjing Medical University. The presence of carbapenemase-encoding genes was detected using PCR and gene sequencing. Genetic relatedness of the bla NDM-5-positive E. coli strains was determined with PFGE and MLST. Susceptibility profiles were measured with broth microdilution method and E-test strips. Transferability features of bla NDM-5 gene were assessed by conjugation experiments, S1-PFGE, southern blotting and PCR-based replicon typing methods. The genetic structures surrounding bla NDM-5 were acquired by whole genome sequencing and PCR mapping. RESULTS: Among the 28 carbapenem-resistant E. coli strains, 18 (64%) were verified as NDM-5 producers. The 18 bla NDM-5-positive E. coli strains showed high resistance to most antibiotics, but 100% were sensitive to colistin and tigecycline. In addition, the 18 bla NDM-5-positive E. coli strains belonged to eight STs, among which ST167, ST410 and ST101 were found to cause clonal spread in the hospital. Further studies found that the bla NDM-5 gene was located on an IncX3-type plasmid, and all plasmids harbored an IS3000-ΔISAba125-IS5-bla NDM-5-bleMBL-trpF-dsbC-IS26 structure. CONCLUSION: The clonal spread of bla NDM-5-positive E. coli strains and horizontal dissemination via the pNDM-MGR 194-like plasmids should draw more attention. Appropriate infection control operations should be performed to prevent the further spread of bla NDM-5.

Characteristics of NDM-1-producing Klebsiella pneumoniae ST234 and ST1412 isolates spread in a neonatal unit.

BACKGROUND: The emergence of carbapenem-resistant Klebsiella pneumoniae (CR-KP) has become a significant problem worldwide and also being a major threat to children and newborns. Here we report an outbreak of NDM-1-producing K. pneumoniae in a neonatal unit. RESULTS: Six CR-KP strains, isolated from neonates with symptoms of infection, were identified using a VITEK-2 compact system, and the clinical data were retrieved from the electronic case records. In vitro susceptibility testing with broth dilution method showed that all six K. pneumoniae isolates were resistant to carbapenems and susceptible to colistin, aminoglycosides, fluoroquinolones and tigecycline. Based on the polymerase chain reaction results, each isolate was found to be blaNDM-1 gene positive. Clonal relationships were analysed using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) and showed that two different PFGE patterns were formed, which belonged to sequence types ST234 and ST1412. Plasmids carrying blaNDM-1 were successfully transferred from four of the six isolates to an Escherichia coli recipient through conjugative assays. S1-PFGE and Southern blot hybridization showed that four NDM-1-producing K. pneumoniae were clonal and carried blaNDM-1 on the same plasmid. The outbreak was effectively controlled by reducing the potential infection sources. All the patients were successfully treated and recovered after receiving an increased dose of carbapenems. Although the source of this outbreak was not clear, comprehensive measures were carried out and the outbreak was effectively controlled. CONCLUSIONS: ST234 and ST1412 of NDM-1-producing Klebsiella pneumoniae are the resistant clone spread in the neonatal unit, comprehensive infection control measures and optimized carbapenem therapy played an important role in controlling this NDM-1-producing K. pneumoniae outbreak.

Epidemiology and risk factors for Clostridium difficile-associated diarrhea in adult inpatients in a university hospital in China.

BACKGROUND: Clostridium difficile-associated diarrhea (CDAD) is an important disease with rising incidence and mortality in western countries. However, studies about CDAD in China are limited. The aims of this study are to investigate the epidemiology and risk factors of CDAD in a university hospital located in Eastern China. METHODS: Diarrhea samples of all adult inpatients were collected for C difficile culture prospectively from August 2013-April 2014. Suspected colonies were identified by biochemical identification cards. Confirmed C difficile isolates were further analyzed for the presence of toxin genes and typed by polymerase chain reaction ribotyping. Patient demographics, presumed risk factors, clinical manifestations, and laboratory findings were collected through inpatient medical record systems retrospectively. RESULTS: In total, 45 stains of toxigenic C difficile were isolated from 315 nonrepetitive diarrhea samples. The isolation rate was 14.29% (45/315). No RT027/ST1 strain was found. An outbreak of CDAD occurred in the digestive ward and was finally found to be caused by ST35 strains during this study. Coloclysis and diabetes were found to be independent risk factors of CDAD, besides the common risk factors previously reported. CONCLUSIONS: CDAD is not uncommon in Chinese hospitals. C difficile ST35 as a new strain causing outbreaks should be noticed. Coloclysis and diabetes are new independent risk factors for CDAD, and further study is needed.

The incidence and drug resistance of Clostridium difficile infection in Mainland China: a systematic review and meta-analysis.

It has been widely reported that the incidence and severity of Clostridium difficile infection (CDI) have increased dramatically in North America and Europe. However, little is known about CDI in Mainland China. In this study, we aimed to investigate the incidence of CDI and the main epidemic and drug-resistant strains of C. difficile in Mainland China through meta-analysis of related studies published after the year 2010. A total of 51 eligible studies were included. The pooled incidence of toxigenic C. difficile among patients with diarrhoea was 14% (95% CI = 12-16%). In Mainland China, ST-37 and ST-3 were the most prevalent strains; fortunately, hypervirulent strains, such as ST-1 (BI/NAP1/027) and ST-11 (RT 078), have only occurred sporadically to date. The rates of C. difficile resistance to ciprofloxacin (98.3%; 95% CI = 96.9-99.7%), clindamycin (81.7%; 95% CI = 76.1-87.3%) and erythromycin (80.2%; 95% CI = 73.5-86.9%) are higher than in other counties; however, none of the C. difficile isolates reported in Mainland China were resistant to metronidazole (n/N = 0/960), vancomycin (n/N = 0/960), tigecycline (n/N = 0/41) or piperacillin/tazobactam(n/N = 0/288).

Influence of long-term inundation and nutrient addition on denitrification in sandy wetland sediments from Poyang Lake, a large shallow subtropical lake in China.

Wetlands at aquatic/terrestrial transition zones may play an important role in nitrogen removal due to the denitrification during inundation events. In this study, air-dried sandy sediment cores from Poyang Lake's wetlands were continuously inundated in the laboratory to investigate the rate, efficiency, and pattern of denitrification at the sediment-water interface (SWI). Denitrification rates responded to inundation in three stages: an adaptive period, a rapid growth period, and a stable period. The average denitrification rates during these stages were 52.62 ± 11.33 µmol N2 m-2 h-1, 115.74 ± 58.40 µmol N2 m-2 h-1 and 187.74 ± 16.44 µmol N2 m-2 h-1, respectively. Multiple regression analysis showed that inundation duration was the most important factor controlling denitrification rates at the SWI rather than nitrate concentrations, which were also positively correlated with denitrification rates. Changes in water content, oxidation-reduction potential (Eh), and pH in the surface sediments, which were consequences of inundation, significantly influenced the denitrification rate (p < 0.05). The N2O/(N2O + N2) flux ratio in denitrification production varied from 1.61% during the adaptive period to 0.03% in the stable period, suggesting that continuous inundation of sediments in aquatic-terrestrial transition zones of Poyang Lake could decrease the proportion of greenhouse gases (N2O). Since inputs of bioavailable nitrogen and phosphorus to Poyang Lake have increased in recent decades, the influence of elevated nutrients on denitrification under continuous inundation were also evaluated by simulation experiments. The results showed that increased nitrate or phosphate loading stimulate denitrification rates in sandy sediments during the inundation process. The addition of nitrate plus phosphate showed a stronger influence on denitrification than single nutrient additions. This study facilitates understanding of the influence of continuous inundation and elevated nutrients on denitrification in sandy sediments in aquatic/terrestrial transition zones.