[Etiological characterization of invasive non-typhoid Salmonella strains in Guangdong Province from 2018 to 2022].

Objective: To understand the serotype distribution, drug resistance and molecular characterization of invasive non-typhoid Salmonella (iNTS) in Guangdong Province from 2018 to 2022 and provide scientific evidence for the prevention and treatment of blood flow infection caused by Salmonella. Methods: Serological identification, antimicrobial susceptibility testing, multilocus sequence typing (MLST), and whole genome sequencing were performed on Salmonella isolated from blood and stool samples in Guangdong from 2018 to 2022. Simultaneously, annotated the sequencing results for drug resistance genes and virulence factors by a microbial gene annotation system. Results: The 136 iNTS strains were divided into 25 serotypes, and Salmonella enteritidis accounted for 38.24% (52/136). The OR of other iNTS serotypes were calculated with Salmonella typhimurium as the control. The OR values of Oreninburg, Rysson, and Pomona serotypes were the highest, which were 423.50, 352.92, and 211.75, respectively. The drug resistance rate of iNTS was 0.74%-66.91%, which was lower than that of non-iNTS (3.90%-77.21%). The main iNTS of drug resistance were ampicillin and tetracycline, with resistance rates of 66.91% (91/136) and 50.00% (68/136), respectively, while the resistance rates to ciprofloxacin (5.88%,8/136), ceftazidime (5.88%,8/136), gentamicin (5.13%,7/136) and cefoxitin (0.74%, 1/136) were relatively low. iNTS carried a variety of drug-resistance genes and virulence factors, but no standard virulence factor distribution has been found. MLST cluster analysis showed that iNTS was divided into 26 sequence types, and ST11 accounted for 38.24% (52/136). Conclusions: The iNTS strains in Guangdong were dominated by Salmonella enteritidis, of which three serotypes, Oreninburg, Rison, and Pomona, may be associated with a higher risk of invasive infection during 2018 to 2022. iNTS was sensitive to clinical first-line therapeutic drugs (cephalosporins and fluoroquinolones), with highly diverse sequences and clear phylogenetic branches. ST11 was the local dominant clone group.

VMAT partial arc technique decreases dose to organs at risk in whole pelvic radiotherapy for prostate cancer when compared to full arc VMAT and IMRT.

Whole pelvic radiotherapy (WPRT) can sterilize microscopic lymph node metastases in treatment of prostate cancer. WPRT, compared to prostate only radiotherapy (PORT), is associated with increased acute gastrointestinal, and hematological toxicities. To further explore minimizing normal tissue toxicities associated with WPRT in definitive IMRT for prostate cancer, this planning study compared dosimetric differences between static 9-field-IMRT, full arc VMAT, and mixed partial-full arc VMAT techniques. In this retrospective study, 12 prostate cancer patients who met the criteria for WPRT were randomly selected for this study. The initial volume, PTV46, included the prostate, seminal vesicles, and pelvic nodes with margin and was prescribed to 4600 cGy. The cone-down volume, PTV78, included the prostate and proximal seminal vesicles with margin to a total dose of 7800 cGy. For each CT image set, 3 plans were generated for each of the PTVs: an IMRT plan, a full arc (FA) VMAT plan, and a mixed partial-full arc (PFA) VMAT plan, using 6MV photons energy. According to RTOG protocols none of the plans had a major Conformity Index (CI) violation by any of the 3 planning techniques. PFA plan had the best mean CI index of 1.00 and significantly better than IMRT (p = 0.03) and FA (p = 0.007). For equivalent PTV coverage, the average composite gradient index of the PFA plans was better than the IMRT and the FA plans with values 1.92, 2.03, and 2.01 respectively. The defference was statistically significant between PFA/IMRT and PFA/FA, with p- values of < 0.001. The IMRT plans and the PFA plans provided very similar doses to the rectum, bladder, sigmoid colon, and femoral heads, which were lower than the dose in the FA plans. There was a significant decrease in the mean dose to the rectum from 4524 cGy with the FA to 4182 cGy with the PFA and 4091 cGy with IMRT (p < 0.001). The percent of rectum receiving 4000 cGy was also the highest with FA at 66.1% compared to 49.9% (PFA) and 47.5% (IMRT). There was a significant decrease in the mean dose to the bladder from 3922 cGy (FA) to 3551 cGy (PFA) and 3612 cGy (IMRT) (p < 0.001). The percent of bladder receiving 4000 cGy was also the highest with FA at 45.4% compared to 36.6% (PFA) and 37.4% (IMRT). The average mean dose to the sigmoid colon decreased from 4177 cGy (FA) to 3893 cGy (PFA) and 3819 cGy (IMRT). The average mean dose to the femoral heads decreased from 2091 cGy (FA) to 2026 cGy (PFA) and 1987 cGy (IMRT). Considering the improvement in plan quality indices recorded in this study including the dose gradient and the dose to organs at risk, mixed partial-full arc plans may be the preferred VMAT treatment technique over full arc plans for prostate cancer treatments that include nodal volumes.

Patterning Chronic Active Demyelination in Slowly Expanding/Evolving White Matter MS Lesions.

BACKGROUND AND PURPOSE: Slowly expanding/evolving lesions measured by conventional T1-weighted/T2-weighted brain MR imaging may contribute to progressive disability accumulation in MS. We evaluated the longitudinal change in myelin and axonal tissue integrity in white matter slowly expanding/evolving lesions by means of the magnetization transfer ratio and DTI radial diffusivity. MATERIALS AND METHODS: Slowly expanding/evolving lesions were detected within the Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of BIIB033 in Participants With Relapsing Forms of Multiple Sclerosis When Used Concurrently With Avonex (SYNERGY) Phase 2 clinical trial dataset (NCT01864148), comprising patients with relapsing-remitting and secondary-progressive MS (n = 299) with T1-weighted/T2-weighted MR imaging at all trial time points (baseline to week 72). RESULTS: Compared with non-slowly expanding/evolving lesions (areas not classified as slowly expanding/evolving lesion) of baseline nonenhancing T2 lesions, slowly expanding/evolving lesions had a lower normalized magnetization transfer ratio and greater DTI radial diffusivity, both in patients with relapsing-remitting MS (n = 242) and secondary-progressive MS (n = 57, P < .001 for all). Although the changes with time in both the normalized magnetization transfer ratio and DTI radial diffusivity between slowly expanding/evolving lesions and non-slowly expanding/evolving lesions were positively correlated (P < .001), a decrease in the normalized magnetization transfer ratio and a greater increase in DTI radial diffusivity were observed in slowly expanding/evolving lesions versus non-slowly expanding/evolving lesions from baseline to week 72 in relapsing-remitting MS and secondary-progressive MS (P < .001 for all). CONCLUSIONS: Patterns of longitudinal change in the normalized magnetization transfer ratio and DTI radial diffusivity in slowly expanding/evolving lesions were consistent with progressive demyelination and tissue loss, as seen in smoldering white matter MS plaques.

First co-infection case of melioidosis and Japanese encephalitis in China.

BACKGROUND: Melioidosis is endemic in Southeast Asia and northern Australia. Infection usually follows percutaneous inoculation or inhalation or ingestion of the causative bacterium, Burkholderia pseudomallei, which is present in soil and surface water in endemic regions. Japanese encephalitis (JE) is a vector-borne viral zoonosis caused by Japanese encephalitis virus (JEV), leading to epidemic encephalitis in Southeast Asia. Both B. pseudomallei and JEV have spread dominantly in the Hainan and Guangdong provinces in China. Here we reported the first case of co-infection of B. pseudomallei and JEV, which was discovered in Huizhou in the Guangdong province in June 2016. CASE PRESENTATION: A 52-year-old man was admitted to the hospital with acute febrile illness and headache, diagnosed as respiratory infection, central nervous system (CNS) infection, septicemia, and hepatic dysfunction. Based on B. pseudomallei-positive blood and cerebrospinal fluid (CSF) cultures, the patient was diagnosed with melioidosis and treated aggressively with antibiotics. However, the patient failed to make a full recovery. Further laboratory tests focused on CNS infection were conducted. The co-infection of B. pseudomallei and JEV was confirmed after the positive IgM antibodies of JEV were detected in both CSF and blood. After diagnosis of co-infection with B. pseudomallei and JEV, the patient was provided supportive care in hospital and recovered after approximately 3 weeks. CONCLUSION: Given the possibility of co-infection of B. pseudomallei and JEV, as well as variable case presentations, it is critical to enhance the awareness, detection, and treatment of co-infection in regard to melioidosis.

Exploration of Fecal Microbiota Transplantation in the Treatment of Refractory Diarrhea After Renal Transplantation.

OBJECTIVE: Exploration of fecal microbiota transplantation in the treatment of refractory diarrhea after renal transplantation. METHODS: Summarize the etiology of 120 cases with diarrhea after renal transplantation from 2014 to 2017 in our hospital. There were 4 recipients of refractory diarrhea who accepted fecal microbiota transplantation with informed consent, and we collected clinical data of stool and bacterial culture, gut microbiota analysis, graft function, electrolytes, immunosuppressant concentrations of prognostic evaluation of patients with fecal transplantation. RESULTS: The absorption of electrolyte is slightly higher and concentration of tacrolimus and creatinine were not significantly changed compared with before. CONCLUSION: Fecal microbiota transplantation provides a new choice to refractory diarrhea after renal transplantation as an innovative treatment, but the effectiveness of fecal microbiota transplantation needs long-term observation and further evaluation through large sample data.

[Emergency cholecystectomy versus percutaneous transhepatic gallbladder drainage followed by delayed cholecystectomy in patients with moderate acute cholecystitis].

Objective: To analysis the curative effect of emergency cholecystectomy (EC) and percutaneous transhepatic gallbladder drainage (PTGBD) followed by delayed cholecystectomy (DC) on the patients with moderate acute cholecystitis. Methods: The perioperative dataof patients in EC group (n=47) and in PTGBD-DC group (n=49) were compared retrospectively. Results: Compared to PTGBD+ DC group, EC patients had a significantly more postoperative abdominal drainage time [(9.0±12.9) vs (3.4±2.1) days, P=0.041], more postoperative hospital stay after cholecystectomy [(8.2±3.2) vs (5.1±1.8) days, P=0.004], more intraoperative bleeding [(101±125) vs (33±37) ml, P=0.003], more patients of LC conversion to open cholecystectomy (OC) (19.1% vs 4.1%, P=0.021) and more patients of OC(14.9% vs 0, P=0.005). Also, there were higher incidence of respiratory failure(14.8% vs 2.0%, P=0.029), and admission for ICU(21.3% vs 2.0 %, P=0.003). Also, patients of total OC in non-biliary surgeons group were more than that of biliary surgeons group statistically(63.2% vs 14.3 %, P=0.001). Conclusion: PTGBD followed by DC in the treatment of moderate acute cholecystitis was better than EC, especially in patients with complicated comorbidities and in non-biliary surgeons.

The significant role of ATG5 in the maintenance of normal functions of Mc3T3-E1 osteoblast.

OBJECTIVE: To observe the effects of autophagy-related gene 5 (ATG5) on the proliferation, differentiation, and apoptosis of Mc3T3-E1 osteoblast as well as the effects of ATG5 on apoptosis of osteoblasts under the conditions of non-oxidative stress and oxidative stress. MATERIALS AND METHODS: ATG5 overexpressing and silencing cell lines were established in this experiment with lentiviral vector and transcription activator-like effect or nuclease (Talen) technique, respectively, using Mc3T3-E1 cells. Cell counting kit-8 (CCK-8) was used to detect the proliferation rate of osteoblasts, and flow cytometry was applied to detect the impacts of overexpressed and silenced ATG5 on the cell cycle. Alizarin red staining was used to detect the mineralization capacity of osteoblasts after 4-week osteoinduction differentiation. Quantitative Real-time polymerase chain reaction (qRT-PCR) and Western blot methods were adopted to detect the levels of gene and protein expressions of runt-related transcription factor 2 (Runx2), osteocalcin (OCN) and collagen I (COL-I) correlated with osteoblast differentiation after 48 h of osteoinduction differentiation. The staining with Annexin V-phycoerythrin/7-amino-actinomycin D (Annexin V-PE/7AAD) and flow cytometry were performed to detect the influence of ATG5 on osteoblast apoptosis. RESULTS: Stable ATG5 overexpressing and silencing Mc3T3-E1 cell lines were established successfully. CCK-8 test results showed that ATG5 silence inhibited cell proliferation, but the overexpression of ATG5 did not result in an obvious change in cell proliferation. Cell cycle did not change when ATG5 was overexpressed, while was stagnated in S-phase when silenced. The number of mineralized nodules of cells was reduced notably when ATG5 was silenced, while the overexpression of ATG5 did not have an impact on mineralization capacity of the cell after 4-week of osteoinduction differentiation. The test results of qRT-PCR and Western blotting suggested that ATG5 silence inhibited the gene and protein expressions of Runx2, OCN, and COL-I, while the influence of overexpressed ATG5 on the expressions of genes related to osteoblastic differentiation was not obvious after 48 h of osteoinduction differentiation. ATG5 silence made the cells easier to be damaged by hydrogen peroxide, which resulted in the rise of apoptosis rate of osteoblasts, while the overexpressed ATG5 inhibited osteoblast apoptosis after treatment with hydrogen peroxide for 12 h. CONCLUSIONS: ATG5 silence can lead to inhibition of osteoblast proliferation and differentiation. Moreover, it makes the cells easier to be damaged by oxidative stress, and it causes an increase in apoptosis. However, the overexpression of ATG5 strengthens the anti-oxidative capacity of osteoblasts and reduces apoptosis. ATG5 may be an effective target of anti-oxidative therapy for osteoporosis, which brings a new direction for the treatment of osteoporosis.

[Circulation and etiological characterization of Salmonella enterica serotype in human in Guangdong province, 2007-2016].

Objective: To understand the circulation, drug resistance and molecular characteristics of Salmonella1, 4, [5], 12: i:- in human in Guangdong province. Methods:Salmonella1, 4, [5], 12: i:- isolated from diarrhea patients in Guangdong during 2007-2016 were detected for drug resistance, genes and PFGE characteristics. Results: A total of 2 960 strains Salmonella1, 4, [5], 12: i: - were isolated from human diarrhea cases during this period. The positive rates of the isolation increased year by year. The male to female ratio of the infection cases was 1.58∶1, and the infection mainly occurred in infants and young children. Except imipenem, Salmonella1, 4, [5], 12: i: - was resistant to other 17 antibiotics to some extent. The drug resistant rates to ceftazidime, cefotaxime and ciprofloxacin increased from 2011 to 2016. Multi-drug resistance was serious, for example, the multi-drug resistant strains with ASSuT accounted for 70.62% (435/616) and the multi-drug resistant strains with ACSuGSTTm accounted for 27.11% (167/616). The lack of fljA, fljB and hin genes, as well as the retaining of iroB, STM2740, STM2757 genes, resulted in the unable expression of FljBenx gene with 8 different defection profiles. There were 934 different PFGE patterns observed in 2 347 strains, which displayed a relatively large fingerprint polymorphism. The major PFGE pattern was JPXX01. GD0226, which was found in 97 strains, accounting for 4.13% (97/2 347). The PFGE patterns in 168 Salmonella1, 4, [5], 12: i: - strains were consistent with that of Salmonella typhimurium. Conclusions:Salmonella1,4,[5], 12: i: - strains has become the major serotype of Salmonella that cause diarrhea in human in Guangdong. The multi-drug resistance of Salmonella1,4, [5], 12: i: - was serious, and since the defection of fljA, fljB and hin genes, the expression of FljBenx protein failed. The PFGE results were diverse, which displayed polymorphism in inheritance.

[Etiologic characteristics of Shigella sonnei strains isolated from some areas of Guangdong province and Guangxi Zhuang Autonomous Region of China, 2014-2016].

Objective: To investigated the etiologic characteristics of Shigella (S.) sonnei strains causing outbreaks and sporadic cases in some areas of Guangdong province and Guangxi Zhuang Autonomous Region during 2014-2016. Methods: Fourteen S. sonnei strains isolated from outbreaks and 6 S. sonnei strains from sporadic cases from Guangdong and Liuzhou of Guangxi Zhuang Autonomous Region were tested for antimicrobial resistance and analyzed by pulsed-field gel electrophoresis (PFGE). Six typical strains were selected for whole genome sequencing typing and compared with 51 strains isolated both at home and abroad from NCBI genome database. Results: The antibiotic resistance test indicated the isolates had high resistance rate to ampicillin, tetracycline, gentamicin, trimethoprim/sulfamethoxazole and nalidixic acid, while sensitive to azithromycin, chloromycetin and imipenem. PFGE showed high similarity (93.2%) among the strains isolated from different areas. The whole genome sequencing analysis also revealed that all the typical strains were clustered into a same evolution branch, close to some strains from Korea. Conclusions: The S. sonnei strains isolated from some areas of Guangdong and Guangxi Zhuang Autonomous Region showed high resistance to commonly used antibiotics, but they were sensitive to azithromycin, chloramphenicol and imipenem. The isolates in this study also showed similar PFGE patterns and close phylogenic evolution.

Role of MLL3 in regulating cardiac stem cells following cardiac cachexia.

OBJECTIVE: Cardiac cachexia is a form of serious illness that results with terminal stage of heart failure. It is associated with unreasonable weight loss and muscle loss with poor prognosis. Cardiac stem cells play a major role in repairing, damaged cardiac tissue and they are regulated by different mechanisms. In the present study, we investigated the role of MLL3 in regulating cardiac stem cells following cardiac cachexia. MATERIALS AND METHODS: To effectively study the cardiac cachexia, we established a Dahl rat model that produces symptoms similar to cachexia. Using histology, we analyzed the acute and chronic stage of cardiac cachexia. Immunohistochemistry and Western blotting were used to analyze the expression of MLL3 and Oct-4. RESULTS: The rat develops an acute form of cachexia after 2 months of fed with high-salt (8% NaCl) diet, which is characterized by inflammation and tissue damage that are observed through the histological sectioning. The chronic cardiac cachexia developed after 5 months of high-salt diet and histologically it shows tissue loss. At the molecular level the stem cell marker, Oct-4, shows elevated expression at acute stage, but down regulated latter in the chronic stage of cardiac cachexia. Also, MLL3 shows a similar pattern of upregulated expression in acute stage of cachexia, but significantly down regulated in the chronic stage of cachexia that implies their role in regulating the cardiac stem cell and their proliferation. CONCLUSIONS: Our results show that the cardiac stem cells in association with MLL3 support in maintaining homeostatic after initial pathological stages of cachexia but not in the chronic stage of cachexia.

[Analysis on risk factors for norovirus outbreaks in Guangdong province, 2008-2015].

Objective: To analyze transmission factors of norovirus outbreaks in Guangdong province during 2008-2015 and provide evidence for the prevention and control of norovirus infection. Methods: Epidemiological analysis was performed on the data of norovirus outbreaks reported in Guangdong from January 1, 2008 to December 31, 2015, which were obtained from the Public Health Emergency Management Information System of Guangdong province. The samples collected from the norovirus outbreaks were detected for norovirus by RT-PCR and the gene sequencing of the positive PCR products were performed. Results: A total of 96 norovirus outbreaks were reported in Guangdong during 2008-2015. Sixteen outbreaks were reported during 2008-2012 and 80 outbreaks were reported during 2013-2015 (83.3%). Eighty-two outbreaks (85.4%) occurred in schools. The infection routes included foodborne transmission in 39 outbreaks (40.6%), person to person transmission in 23 outbreaks (24.0%) and waterborne transmission in 8 outbreaks (7.3%). The gene sequencing results showed that variant GⅡ.4/Sydney2012 was the predominant pathogen for 6 of the 20 outbreaks (30.0%) during 2012-2013. Variant GⅡ.17 was the predominant pathogens for 33 of the 53 outbreaks (62.3%) during 2014-2015. Conclusion: The norovirus outbreaks in Guangdong during 2008-2015 were caused by foodborne and person to person transmissions of two emerging variant: GⅡ.4/Sydney2012 and GⅡ.17.

Serological evidence for exposure to avian influenza viruses within poultry workers in southern China.

The risk of infection with avian influenza viruses for poultry workers is relatively unknown in China, and study results are often biased by the notification of only the severe human cases. Protein microarray was used to detect binding antibodies to 13 different haemagglutinin (HA1-part) antigens of avian influenza A(H5N1), A(H7N7), A(H7N9) and A(H9N2) viruses, in serum samples from poultry workers and healthy blood donors collected in the course of 3 years in Guangdong Province, China. Significantly higher antibody titre levels were detected in poultry workers when compared to blood donors for the most recent H5 and H9 strains tested. These differences were most pronounced in younger age groups for antigens from older strains, but were observed in all age groups for the recent H5 and H9 antigens. For the H7 strains tested, only poultry workers from two retail live poultry markets had significantly higher antibody titres compared to blood donors.

PTPRO represses ERBB2-driven breast oncogenesis by dephosphorylation and endosomal internalization of ERBB2.

The plasma membrane-associated tyrosine phosphatase PTPRO is frequently transcriptionally repressed in cancers and signifies poor prognosis of breast cancer patients. In this study, deletion of Ptpro in MMTV-Erbb2 transgenic mice dramatically shortened the mammary tumor latency and accelerated tumor growth due to loss of Ptpro within the breast cancer cells but not in surrounding tissue as confirmed by hetero-transplantation studies. Both in vitro and in vivo data demonstrated that the phosphatase activity was required for the inactivation of ERBB2 and its downstream signaling. PTPRO regulated the phosphorylation status of ERBB2 at Y1248. Co-immunoprecipitation and proximity ligation assay (Duolink) indicated that PTPRO directly physically interacted with ERBB2. Moreover, PTPRO phosphatase activity shortened the half-life of ERBB2 by increasing endocytotic degradation. PTPRO reexpression by demethylation treatment using 5-azacytidine reduced the proliferation and colony formation potential in ERBB2-positive breast cancer cells. Taken together, PTPRO inhibited ERBB2-driven breast cancer through dephosphorylation leading to dual effects of ERBB2 signaling suppression and endosomal internalization of ERBB2, Therefore, reexpression of PTPRO may be a potential therapy for ERBB2-overexpressing breast cancer.

Ballistic Graphene Josephson Junctions from the Short to the Long Junction Regimes.

We investigate the critical current I_{C} of ballistic Josephson junctions made of encapsulated graphene-boron-nitride heterostructures. We observe a crossover from the short to the long junction regimes as the length of the device increases. In long ballistic junctions, I_{C} is found to scale as ∝exp(-k_{B}T/δE). The extracted energies δE are independent of the carrier density and proportional to the level spacing of the ballistic cavity. As T→0 the critical current of a long (or short) junction saturates at a level determined by the product of δE (or Δ) and the number of the junction's transversal modes.

[Active etiological surveillance for foodborne diseases in Guangdong province, 2013-2014].

Objective: To study the infection status, serotypes, drug resistance and molecular characteristics of Salmonella, Shigella, Vibrio parahemolyticus, enterotoxigenic Escherichia (E.) coli (ETEC), pathogenic E. coli (EPEC), Shiga Toxin producing E. coli (STEC) and Enteroinvasive E. coli (EIEC) collected from diarrhea patients in Guangdong. Methods: The strains of Salmonella, Shigella, V. parahemolyticus and 4 kinds of E. coli isolated from foodborne diseases surveillance during 2013-2014 were collected to conduct serotyping, drug resistance test and pulsed-field gel electrophoresis (PFGE). Results: A total of 3 372 stains of pathogens were isolated from 57 834 stool samples during 2013-2014, the overall positive rate was 5.83% and the positive rate of Salmonella was highest, followed by that of V. parahemolyticus, 4 kinds of E. coli and Shigella. And 3 213 strains of Salmonella were divided into 143 serotypes. The most prevalent serotypes were Salmonella typhimurium, 4, 5, 12: i:-, Enteritidis, Stanley and Derby. Salmonella was sensitive to cephalosporin and fluoroquinolones, and showed significant differences in drug resistance rate among different serotypes. In top 10 common serotypes, S. enteritidis and S. derby were most resistant to cephalosporin and ciprofloxacin respectively. PFGE was performed for 2 289 strains of Salmonella, showing distribution diversity and significant fingerprint polymorphisms. The 85 strains of V. parahemolyticus were divided into 10 serotypes, O3∶K6 (61.18%) was the most common serotype, followed by O4∶K8. The results showed that the carrying rate of virulence genes tdh (81.18%) was high, while the carrying rate of trh was low (7.06%), and there were 10 strains carrying no the two kinds of virulence genes. The sensitive rate of V. parahemolyticus to imipenem, nalidixic acid, SMZ-TMP, chloramphenicol and tetracycline were more than 95%. Thirteen strains of Shigella were detected, including 9 strains of Shigella sonnei, 3 strains of Shigella flexneri and 1 strains of Shigella bogdii. The strains all showed sensitivity to ceftazidime, ciprofloxacin and chloramphenicol (76.92%). There were 86 strains of E. coli detected, including 29 strains of ETEC (33.72%), 27 strains of EPEC (31.39%), 27 strains of STEC (31.39%) and 3 strains of EIEC (3.48%). Conclusions: In the active etiological surveillance for foodborne diseases in Guangdong during 2013-2014, the detection rate of Salmonella was highest (5.57% ), followed by that of V. parahemolyticus, 4 kinds of E. coli and Shigella. Salmonella, V. parahemolyticus and Shigella were sensitive to cephalosporin and fluoroquinolones. Clustered cases of Salmonella infection were found in the surveillance, but no outbreaks occurred.

[Study on Salmonella serotyping by use of Microsphere-based Liquid Array method].

OBJECTIVE: To understand the effect of serotyping on Salmonella isolates, by use of Microsphere-based Liquid Array method, among diarrhea patients, in Guangdong. METHODS: Salmonella isolated from humans in Guangdong province were serotyped on the Microsphere-based Liquid Array platform with SSA kit. RESULTS: A total of 4 942 Salmonella strains with 189 serotypes, were identified in Guangdong province in 2010-2014. The top 100 serotypes accounted for 98.08% (4 847/4 942) of all the strains. 98% of the top 100 species serotypes could completely be serotyped with SSA kit. In order to detect O antigen among 198 isolates with SSA kit, 181 strains were carrying the O antigen, with the coincidence rate as 100%. However, under the SSA, 98.32% (528/537) of the H antigen could be detected and were consistent with the traditional serum agglutination test. The coincidence rate of fljB gene was 93.09% (175/188), with false negative rate and false positive rate of fljB gene as 7.35% (9/134) and 7.41% (4/54) respectively. The coincidence rate of sdf gene and Vi gene were 100%. 11 out of the 12 Salmonella strains could not be serotyped under the traditional methods but were successfully serotyped by the molecular serotyping method. CONCLUSIONS: Using the SSA kit, more than 96% of the anthropogenic Salmonella strains could be serotyped in Guangdong province. Comparing with the traditional methods, the coincidence rate of serotyping appeared over 98% . Under the Microsphere-based Liquid Array techniques, the molecular serotyping method appeared faster and more accurate on Salmonella serotyping than those traditional methods.

Genetic relatedness of selected clinical Vibrio cholerae O139 isolates from the southern coastal area of China over a 20-year period.

Vibrio cholerae O139 emerged as a causative agent of epidemic cholera in 1992 in India and Bangladesh, and was subsequently reported in China in 1993. The genetic relatedness and molecular characteristics of V. cholerae O139 in Guangdong Province, located in the southern coastal area of China, remains undetermined. In this study, we investigated 136 clinical V. cholerae O139 isolates from 1993 to 2013 in Guangdong. By conventional PCR, 123 (90·4%) isolates were positive for ctxB, ace and zot. Sequencing of the positive amplicons indicated 113 (91·7%) isolates possessed the El Tor allele of ctxB (genotype 3); seven carried the classical ctxB type (genotype 1) and three harboured a novel ctxB type (genotype 5). With respect to tcpA, 123 (90·4%) isolates were positive for the El Tor allele. In addition, pulsed-field gel electrophoresis (with NotI digestion) differentiated the isolates into clusters A and B. Cluster A contained seven of the non-toxigenic isolates from 1998 to 2000; another six non-toxigenic isolates (from 1998 and 2007) and all of the toxigenic isolates formed cluster B. Our results suggest that over a 20-year period, the predominant O139 clinical isolates have maintained a relatively tight clonal structure, although some genetic variance and shift has occurred. Our data highlight the persistence of toxigenic V. cholerae O139 in clinical settings in the southern coastal area of China.

Supercurrent in the quantum Hall regime.

A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing.

Imported case of MERS-CoV infection identified in China, May 2015: detection and lesson learned.

At the end of May 2015, an imported case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection was confirmed in China. The patient is in a stable condition and is still undergoing treatment. In this report, we summarise the preliminary findings for this imported case and the results of contact tracing. We identified 78 close contacts and after 14 days of monitoring and isolation, none of the contacts presented symptoms and all tested negative for MERS-CoV.