Clostridioides difficile is a key pathogen of antibiotic related diarrhea and hospital associated infection, causing several outbreaks in Europe and North Americans and resulting in severe disease burden. However, the standardized diagnostic principle and detection specifications in C. difficile infection (CDI) survey are limited in China, and the infection rate and disease burden of CDI in China are unclear. Therefore, National Institute for Communicable Disease Control and Prevention,National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, together with another 11 institutions, draft the group standard entitled "Diagnosis of Clostridium difficile infection (T/CPMA 008-2020)" of Chinese Preventive Medicine Association. Based on the principle of "legality, scientificity, advancement, and feasibility", this standard clarifies risk factors, diagnosis principles, diagnoses and differential diagnoses in order to improve the accuracy of CDI diagnosis in clinical practice, guide the surveillance for CDI, and understand the infection rate and disease burden of CDI in China .

Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta oscillations in implicit timing tasks are lacking. In this study, we set up an implicit motor timing task and found a modulation pattern of beta oscillations with temporal perception during movement preparation. We trained two macaques in a repetitive visually-guided reach-to-grasp task with different holding intervals. Spikes and local field potentials were recorded from microelectrode arrays in the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. We analyzed the association between beta oscillations and temporal interval in fixed-duration experiments (500 ms as the Short Group and 1500 ms as the Long Group) and random-duration experiments (500 ms to 1500 ms). The results showed that the peak beta frequencies in both experiments ranged from 15 Hz to 25 Hz. The beta power was higher during the hold period than the movement (reach and grasp) period. Further, in the fixed-duration experiments, the mean power as well as the maximum rate of change of beta power in the first 300 ms were higher in the Short Group than in the Long Group when aligned with the Center Hit event. In contrast, in the random-duration experiments, the corresponding values showed no statistical differences among groups. The peak latency of beta power was shorter in the Short Group than in the Long Group in the fixed-duration experiments, while no consistent modulation pattern was found in the random-duration experiments. These results indicate that beta oscillations can modulate with temporal interval in their power mode. The synchronization period of beta power could reflect the cognitive set maintaining working memory of the temporal structure and attention.

Objective: To evaluate the performance of a chromogenic agar developed by our laboratory for the isolation and culture of Clostridium difficile (CDCA). Methods: The chromogenic specificity of CDCA was evaluated by inoculation of C. difficile and other standard strains, and the sensitivities of CDSA (BD), CDIF (BioMérieux) and CDCA were determined by the C. difficile standard strains respectively. A total of 120 clinical stool specimens were cultured for C. difficile by three chromogenic media respectively. The colonies were further identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and tpi gene was also detected. The sample which could be identified as C. difficile in any of the three chromogenic medium was defined as true positive. Results: Most of standard strains were inhibited by CDCA, however some Clostridium species including C. clostridiiforme, C. bifermentans, C. tertium and Bacteroides fragilis grew lightly with chromogenic reaction. The sensitivities of CDSA, CDIF and CDCA were 2.0×105 CFU/mL, 8.0×101 CFU/mL and 4.0×10 2 CFU/mL, respectively. Among the 120 samples, 31 (25.8%) were defined as true C. difficile positive samples, while the positive rate of CDSA, CDIF and CDCA were 25 (20.8%), 28 (23.3%) and 26 (21.7%), respectively. There was no significant difference for clinical diarrhea specimens among the three chromogenic media (χ 2 =0.418, P=0.811). In comparison to the standard, the sensitivity, specificity, positive predictive value and negative predictive value were 83.8%, 100%, 100% and 94.7% for CDCA; 90.3%, 98.9%, 96.6% and 96.7% for CDIF; and 80.6%, 100%, 100% and 93.7% for CDSA. Conclusion The CDCA developed by our laboratory could be used to preliminarily isolate C. difficile with good specificity and sensitivity.

We employed a multiplex polymerase chain reaction (PCR) coupled with capillary electrophoresis (mPCR-CE) targeting six Clostridium difficile genes, including tpi, tcdA, tcdB, cdtA, cdtB, and a deletion in tcdC for simultaneous detection and characterization of toxigenic C. difficile directly from fecal specimens. The mPCR-CE had a limit of detection of 10 colony-forming units per reaction with no cross-reactions with other related bacterial genes. Clinical validation was performed on 354 consecutively collected stool specimens from patients with suspected C. difficile infection and 45 isolates. The results were compared with a reference standard combined with BD MAX Cdiff, real-time cell analysis assay (RTCA), and mPCR-CE. The toxigenic C. difficile species were detected in 36 isolates and 45 stool specimens by the mPCR-CE, which provided a positive rate of 20.3% (81/399). The mPCR-CE had a specificity of 97.2% and a sensitivity of 96.0%, which was higher than RTCA (x = 5.67, P = 0.017) but lower than BD MAX Cdiff (P = 0.245). Among the 45 strains, 44 (97.8%) were determined as nonribotype 027 by the mPCR-CE, which was fully agreed with PCR ribotyping. Even though ribotypes 017 (n = 8, 17.8%), 001 (n = 6, 13.3%), and 012 (n = 7, 15.6%) were predominant in this region, ribotype 027 was an important genotype monitored routinely. The mPCR-CE provided an alternative diagnosis tool for the simultaneous detection of toxigenic C. difficile in stool and potentially differentiated between RT027 and non-RT027.
Clostridium Infections ; diagnosis ; Clostridium difficile ; genetics ; Electrophoresis, Capillary ; Feces ; microbiology ; Genes, Bacterial ; Humans ; Polymerase Chain Reaction ; Ribotyping ; Sensitivity and Specificity

Objective In comparison with Xpert C.difficile/Epi through detection of Clostridium difficile toxin genes from clinical stool , the performance of a laboratory-developed ( LD) assay was evaluated in detail.Methods A total of 176 stool specimens collected from patients with diarrhea in the First People′s Hospital of Yuhang District and the People′s Hospital of Yingzhou , Ningbo from August 1 to December 30 were detected by the two assays in parallel , and meanwhile the C.difficile strains will be isolated and identified for C.difficile toxin genes by a conventional PCR assay .The Cross-tabs Analysis was used for the results by using SPSS20.0 software.Results In comparison with the results of Xpert C.difficile/Epi as the standard, the LD assay had a sensitivity of 91.7％(22/24), a specificity of 100％(152/152), a positive predictive value (PPV) of 100％(22/22), and negative predictive value (NPV) 98.7％(152/154).The results of two assays were statistically coherent (Kappa=0.950, P<0.001).In comparison with culture and detection of toxin genes results , the LD assay had a sensitivity of 90.0％ ( 18/20 ) , a specificity of 97.0％(152/156), a PPV of 81.8％ (18/22), and NPV of 98.7％ (152/154)(Kappa=0.838, P<0.001), and the Xpert C.difficile/Epi assay had a sensitivity of 90.0％ (18/20), a specificity of 96.0％(150/156), a PPV of 75.0％(18/24), and NPV of 98.7％ (150/152)(Kappa=0.792, P<0.001). Conclusions The performance of the LD assay was similar to that of the Xpert C .difficile/Epi kit in detection of toxigenic C.difficile.The LD assay could be directly applied to detection of toxigenic C.difficile from clinical stool samples .The clinical application of this LD assay will also provide a domestic and promising diagnostic assay for diagnosis of C.difficile infection in China.

Objective In comparison of the performances for the detection of Clostridium difficile toxin B genes from stool between BD MAX Cdiff assay and a laboratory-developed (LD) assay.The LD assay was evaluated in clinical application.Methods This study was a clinical application research.A total of 147 stool specimens from patients with diarrhea in Hangzhou First Hospital affiliated with Zhejiang Chinese Medical University were detected by the two assays from 1 July to 30 September 2014.DNA extraction and amplification of the tcdB gene were performed automatically on the BD MAX platform.Meanwhile, the tcdA and tcdB gene were detected by the LD real-time PCR assay after DNA extraction.Then, the results were analyzed by use of SPSS 10.0.Results A total of 147 stool samples were collected.There were 33 C.difficile positive cases and 114 negative cases detected by both of two assays.However, there were four stool samples had incongruent results.In comparison with BD MAX, the LD assay had a sensitivity of 93.94% (31/33), a specificity of 98.25% (112/114), a positive predictive value of 93.94% (31/33), and negative predictive value 98.25% (112/114).Furthermore, the results of the LD assay were statistically coherent with that of the BD assay (Kappa=0.922, P<0.01).Conclusions The LD assay was highly sensitive and accurate as BD MAX Cdiff assay in the detection of toxigenic Clostridium difficile.Furthermore, this LD assay could be also applied to detection of clinical stool samples directly with low cost.The assay will be more promising in diagnosis of toxigenic C.difficile in clinical application in China due to no additional instrument needed.

Background: Anti-programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) immunotherapy has been proved to be effective on gastric cancer in ongoing clinical trials. However, the value of PD-L1 in predicting responses of patients with gastric cancer to anti-PD-1/PD-L1 immunotherapy is controversial. Some studies suggested that intra- and inter-tumoral heterogeneity of PD-L1 expression might explain the controversy. This study aimed to analyze the expression of PD-L1, PD-L2, and PD-1 as well as CD8(+) T-cell density in primary tumors and lymph nodes from patients with stage T1-4N+M0 gastric adenocarcinoma to explore the heterogeneity of PD-1 signaling pathway molecules. Methods: In primary tumors and metastatic as well as non-metastatic lymph nodes from patients with stage T1-4N+M0 gastric adenocarcinoma, we detected PD-L1 and PD-L2 expression with immunohistochemistry. CD8(+) T-cell density in primary tumors and PD-1 expression on CD8(+) T cells were detected with immunofluorescence. Uni-variate analysis was used to determine the prognostic values of them. Cox proportional hazard regression model was used to identify independent risk factors that affect patients' overall survival and disease-free survival. Results: Among 119 eligible patients who had undergone surgical resection, the positive rate of PD-L1 was higher in metastatic lymph nodes than in primary tumors (45.4％ vs. 38.7％,P= 0.005); the positive rate of PD-1 on CD8(+) T cells was significantly higher in primary tumors and metastatic lymph nodes than in tumor-free lymph nodes (both P < 0.001). The intensity of PD-1 expression on CD8(+) T cells in primary tumors and in metastatic lymph nodes were stronger than that in tumor-free lymph nodes from the same patient. Beside, the positive rate of PD-L2 did not show any differences between primary tumors and metastatic lymph nodes. In multivariate analysis, PD-L1 expression, PD-L2 expression, a low density of CD8(+) T cells in primary tumors, and PD-1 expression on CD8(+) T cells in primary tumors were associated with poor prognosis.Conclusion: The expression of PD-L1 is heterogeneous in primary tumors and in metastatic lymph nodes from patients with stage T1-4N+M0 gastric adenocarcinoma, which might explain the inconsistent results in assessing the prognostic value of PD-L1 expression in previous studies.

TcdA and B toxins secreted by Clostridium difficile( CD) are two important causes of diseases in organisms. The expression of tcdA and tcdB genes is regulated by a few factors located in the pathogenicity locus ( PaLoc) .Studies have indicated that the tcdC gene is likely to act as a negative regulator of toxin gene expression.So far, it has been debatable whether tcdC gene is regarded as a negative regulator.The mechanism of tcdC gene in pathogenesis remains unclear.In this paper, the structure and function of the tcdC gene are summarized, which will help study the mechanism of tcdC gene and obtain optimal drug targets.

Objective To construct prokaryotic expression vectors for glutamate dehydrogenase(GDH)of Clostridium difficile(CD),and express recombinant GDH in Escherichia coli,and identify its antigenicityed.Methods The entire gene of GDH was cloned from ATCC43255 genome DNA.The recombinant antigens were expressed in E.coli with IPTG induction and purified by Ni-NATBeads.The antigenicity was detected using CD Qick Chek Complete dual-antigen EIA. Results Prokaryotic expression vectors of CD GDH were constructed successfully.The antigen could be identified by specific anti-GDH antibodies.Conclusion The GDH antigen can be used to prepare corresponding antibodies,which facilitate the development of immunoassay for CD GDH.