Serotype distribution, trend of multidrug resistance and prevalence of ß-lactamase resistance genes in human Salmonella isolates from clinical specimens in Guizhou, China.

Salmonella, one of the major causes of foodborne infections, can cause bacterial foodborne illness. We investigated the serotype distribution, multidrug resistance (MDR), and ß-lactamase resistance genes of human Salmonella isolates collected from clinical specimens in Guizhou, China, between 2013 and 2018. A total of 363 Salmonella isolates were collected from clinical specimens at 17 surveillance hospitals. Twenty-four serotypes were identified by sliding agglutination test. S. Enteritidis (33.9%), Salmonella 4,[5],12:i:- (24.0%), S. Typhimurium (16.3%), S. London (6.3%), and S. Derby (3.9%) were the top five serotypes. In 2018, the most common serotype changed from S. Enteritidis to S. Typhimurium. Among the 363 Salmonella isolates, 97.5% of isolates were resistant to at least one class of antimicrobial agents. For cephalosporins, ceftriaxone had the highest resistance rate of 10.5%, and cefepime and cefoxitin were 8.0% and 2.2%, respectively. Three hundred and one (82.9%) Salmonella isolates showed MDR. Salmonella 4,[5],12:i:- had the highest MDR rate with 94.2%, followed by S. London (91.3%) and S. Typhimurium (88.1%). Multidrug resistance rates of Salmonella isolates in Guizhou from 2013 to 2017 increased from 75.8% to 86.7%. Sixteen isolates (4.4%) showed extensive drug resistance. One hundred thirty-four antimicrobial resistance patterns were found. Two hundred and forty-one (66.4%) isolates carried at least one ß-lactamase resistance gene. The blaTEM gene (61.2%) was the most prevalent resistant gene in all Salmonella isolates, followed by the blaCTX-M gene (6.1%) and blaOXA-1 gene (4.1%). Our findings showed that the MDR rate of Salmonella isolates from Guizhou province increased year by year. Therefore, systematic and long-term surveillance on MDR Salmonella isolates from clinical patients should be further strengthened.

The CRISPR genotypes and genetic diversity of different serogroups of nontyphoidal Salmonella in Guizhou Province, 2013-2018.

Nontyphoidal Salmonella is a bacterial and foodborne pathogen that poses a severe public health threat. However, the genetic diversity of different serogroups of nontyphoidal Salmonella in Guizhou is unknown. This study aimed to obtain the RNA secondary structure of the typical direct repeat sequences, the characteristics of clustered regularly interspaced short palindromic repeats (CRISPR) genotypes, and the genetic diversity of different serogroups of nontyphoidal Salmonella strains. The 342 nontyphoidal Salmonella strains were collected from nine cities (prefectures) of Guizhou province during 2013-2018, serotyped by slide agglutination, and examined the molecular genotypes by CRISPR method. The strains were divided into five serogroups. The dominant serogroup was group B (47.08%), followed by group D1 (36.55%). One hundred and thirty-five CRISPR genotypes were detected with 108 novel spacer sequences amongst 981 unique spacer sequences. The diversity of nontyphoidal Salmonella CRISPR loci was not only the deletion, duplication, or point mutation of spacer sequences but also the acquisition of new spacer sequences to form novel genotypes. The CRISPR genotyping was an effective typing method that could reveal the genetic diversity of different nontyphoidal Salmonella serotypes except for S. Enteritidis.

Highly prevalent MDR, frequently carrying virulence genes and antimicrobial resistance genes in Salmonella enterica serovar 4,[5],12:i:- isolates from Guizhou Province, China.

Salmonella enterica serovar 4,[5],12:i:-, a monophasic variant of Salmonella Typhimurium lacking the phase 2 flagellin, is one of the common serotypes causing Salmonellosis worldwide. However, information on Salmonella serovar 4,[5],12:i:- from Guizhou Province has lacked so far. This study aimed to investigate the antimicrobial resistance, the presence of antimicrobial resistance genes and virulence genes, and characterize the MLST genotypes of Salmonella serovar 4,[5],12:i:- isolates from Guizhou province, China. We collected 363 non-typhoid Salmonella (NTS) isolates of Guizhou from 2013 to 2018. Biochemical identification, serogroups testing, and specific multiplex polymerase chain reaction (mPCR) assay were conducted to identify Salmonella 4,[5],12:i:- isolates. Isolates were determined the antimicrobial resistance by the micro broth dilution method, detected the presence of antimicrobial resistance genes and virulence genes by PCR, and examined the molecular genotyping by Multilocus sequence typing (MLST). Eighty-seven Salmonella 4,[5],12:i:- isolates were detected, accounting for 23.9% (87/363) of the total NTS isolates. All Salmonella 4,[5],12:i:- isolates showed highly resistant to sulfaoxazole (93.1%), streptomycin (90.8%), ampicillin (88.5%), tetracycline (86.2%) and doxycycline (86.2%). A high proportion (94.2%) of multi-drug resistance (MDR) isolates were found. Most (83.9%) Salmonella 4,[5],12:i:- isolates carried four antimicrobial resistance genes, especially blaTEM-1, strA-strB, sul2, and tetB genes. Salmonella 4,[5],12:i:- isolates showed a high rate of invA, sseL, mgtC, siiE, sopB, gipA, gtgB, sspH1, and sspH2 (72.4%~98.9%). On the contrary, none of the isolates were detected the spvC and pefA genes. MLST analysis revealed three sequence types (STs), and ST34 (97.7%) was the dominant sequence type. This study is the first report of Salmonella 4,[5],12:i:- in humans from Guizhou province, China. The data might be useful for rational antimicrobial usage against Salmonella 4,[5],12:i:- infections, risk management, and public health strategies in Guizhou.

Inhibition studies of ketol-acid reductoisomerases from pathogenic microorganisms.

Ketol-acid reductoisomerase (KARI), the second enzyme in the branched-chain amino acid (BCAA) biosynthesis pathway, is an emerging target for the discovery of biocides. Here, we demonstrate that cyclopropane-1,1-dicarboxylate (CPD) inhibits KARIs from the pathogens Mycobacterium tuberculosis (Mt) and Campylobacter jejuni (Cj) reversibly with Ki values of 3.03 µM and 0.59 µM, respectively. Another reversible inhibitor of both KARIs, Hoe 704, is more potent than CPD with Ki values of 300 nM and 110 nM for MtKARI and CjKARI, respectively. The most potent inhibitor tested here is N-hydroxy-N-isopropyloxamate (IpOHA). It has a Ki of ~26 nM for MtKARI, but binds rather slowly (kon ~900 M-1s-1). In contrast, IpOHA binds more rapidly (kon ~7000 M-1s-1) to CjKARI and irreversibly.

Antimicrobial resistance and molecular genotyping of Salmonella enterica serovar Enteritidis clinical isolates from Guizhou province of Southwestern China.

Salmonella enterica serovar Enteritidis (S. Enteritidis) is the most common and essential serotype that causes salmonellosis in Guizhou province. This study aimed to investigate the antimicrobial resistance (AMR) and molecular genotyping of 79 S. Enteritidis clinical isolates from 2011 to 2016 in Guizhou, China. Antimicrobial resistance and minimum inhibitory concentrations (MICs) of S. Enteritidis clinical isolates were detected by micro broth dilution method against ten classes 16 antimicrobial agents, and molecular genotyping were examined by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA). All (100%) isolates showed resistance to at least one antimicrobial. Resistance to nalidixic acid (98.7%) was the highest, followed by sulfamethoxazole (87.3%) and ampicillin (77.2%). The majority of isolates (92.4%) showed decreased susceptibility to ciprofloxacin. Resistance to the third and fourth-generation cephalosporins was observed. Twenty-six AMR profiles were observed, and the predominant AMR profile was ampicillin-streptomycin-sulfamethoxazole-amoxicillin/clavulanic acid-nalidixic acid. A high burden of multidrug resistance (MDR) (81.0%) was found. Seventy-nine S. Enteritidis isolates were divided into 33 different pulsotypes (PTs), and the most frequent PT was PT18. Twenty-six different MLVA types (MTs) were generated with seven VNTR loci analysis of these isolates. The dominant PTs and MTs were persistent during 2011-2016. S. Enteritidis clinical isolates showed higher genetic diversity using PFGE combined with MLVA grouped into 60 PT-MT genotypes. No correlation was observed between genotypes, AMR profiles and geographic location. These data revealed the characteristics of AMR and molecular genotyping of S. Enteritidis clinical isolates in Guizhou province. These results highlight that strengthening the AMR and molecular genotyping surveillance is essential to prevent and control salmonellosis in Guizhou. PFGE combined with MLVA should be powerful tools for the molecular genotyping of S. Enteritidis isolates.

Correction to: Genetic characterization of Bacillus anthracis in Guizhou Province, Southwest of China.

ERRATUM: Upon publication of the original article (1) it was highlighted by the authors that a grant awarded to support the research work of the study was missed in the acknowledgements. It should also be acknowledged that the grant titled "Genotyping and Molecular Epidemiological Characteristic of Bacillus anthracis in Guizhou Province" awarded by the Program of Natural Science Foundation of Guizhou Province (Grant No. Qian Ke He J Word [2015] 2084)also contributed to the resources for this research. This has since been formally noted in this correction article.

Mechanism study on a plague outbreak driven by the construction of a large reservoir in southwest china (surveillance from 2000-2015).

BACKGROUND: Plague, a Yersinia pestis infection, is a fatal disease with tremendous transmission capacity. However, the mechanism of how the pathogen stays in a reservoir, circulates and then re-emerges is an enigma. METHODOLOGY/PRINCIPAL FINDINGS: We studied a plague outbreak caused by the construction of a large reservoir in southwest China followed 16-years' surveillance. CONCLUSIONS/SIGNIFICANCE: The results show the prevalence of plague within the natural plague focus is closely related to the stability of local ecology. Before and during the decade of construction the reservoir on the Nanpan River, no confirmed plague has ever emerged. With the impoundment of reservoir and destruction of drowned farmland and vegetation, the infected rodent population previously dispersed was concentrated together in a flood-free area and turned a rest focus alive. Human plague broke out after the enzootic plague via the flea bite. With the construction completed and ecology gradually of human residential environment, animal population and type of vegetation settling down to a new balance, the natural plague foci returned to a rest period. With the rodent density decreased as some of them died, the flea density increased as the rodents lived near or in local farm houses where had more domestic animals, and human has a more concentrated population. In contrast, in the Himalayan marmot foci of the Qinghai-Tibet Plateau in the Qilian Mountains. There are few human inhabitants and the local ecology is relatively stable; plague is prevalence, showing no rest period. Thus the plague can be significantly affected by ecological shifts.

Influence of angiogenesis on neural stem cell proliferation in the subventricular zone after focal cerebral ischemia/reperfusion / 中国组织工程研究

BACKGROUND:The angiogenesis may be related to the proliferation of neural stem ceils,but there is still no unified view.OBJECTIVE:To observe the influence of angiogenesis on neural stem cell proliferation in the subventricular zone of rats after focal cerebral ischemia/reperfusion.METHODS:Male Sprague-Dawley rats were randomly divided into normal group,sham group,vascular endothelial growth factor (VEGF)+cerebral ischemia/reperfusion group,normal saline (NS)+cerebral ischemia/reperfusion group.The injection was done via the lateral cerebral ventricle.Then,each group was subdivided into four groups (1,2,7,14 days after ischemia/reperfusion).Focal cerebral ischemia/reperfusion models were made by the thread method.After modeling,the corresponding intervention was given in each group.The expression changes of Nestin and vWF mRNA in the subventricular zone were detected in all groups by immunohistochemical staining and real-time PCR,respectively.RESULTS AND CONCLUSION:There was a certain increase in vWF and Nestin positive expression in the subventricular zone after cerebral ischemia/reperfusion.At 7 days after ischemia,the expression of vWF mRNA and Nestin reached the peak,indicating the proliferation of neural stem cells in the subventricular zone after cerebral ischemia/reperfusion is associated with the time of angiogenesis.In addition,the expression of vWF mRNA and Nestin was significantly higher in the VEGF+cerebral ischemia/reperfusion group than the other two groups,indicating angiogenesis could promote the proliferation of neural stem ceils in the subventricular zone of rats after cerebral ischemia/reperfusion.

Genetic characterization of Bacillus anthracis in Guizhou Province, Southwest of China.

BACKGROUND: Bacillus (B.) anthracis is the pathogen that causes fatal anthrax. Guizhou Province is an old foci of anthrax in the southwest of China. Human anthrax has also been frequently reported in Guizhou in recent year. However, there is limited information on the genetic background of local B. anthracis isolates in Guizhou Province. Strain-specific detection of this bacterium using molecular approaches has enhanced our knowledge of microbial genetics. In the present study, we employed Multiple Locus Variable Number Tandem Repeats (VNTR) Analysis (MLVA) assay to analyze the genetic characteristics of B. anthracis strains isolated in Guizhou Province and their relationships to worldwide distributed isolates. RESULTS: A total of 32 isolates of B. anthracis from soil, human, cattle, dog and water of different anthrax epidemics in Guizhou Province from 2006 to 2011 were confirmed with phage lysis test, penicillin inhibition test and PCR. MLVA-8 discriminated them into 28 unique MLVA types (MT G1 - G28), which were novel MTs compared with the previous reports. Cluster tree based on 32 isolates from Guizhou Province and 76 worldwide distributed isolates (30 MTs) showed they were divided into three clusters, designated A, B and C. All the 32 isolates were distributed in cluster A, which were further grouped into A1, A2, A3 and A4 sub-clusters. 32 isolates from Guizhou Province were closely grouped in each of the sub-clusters, respectively. Minimum Spanning Tree (MST) based on the MLVA data showed that the 28 MLVA profiles of isolates from Guizhou Province and 30 MLVA profiles of worldwide distributed isolates formed three clonal complexes (CCs) and ten singletons. CONCLUSIONS: 28 novel MTs of B. anthracis from Guizhou were revealed and their relationships to worldwide isolates were showed. The results will provide important information for prevention of anthrax and also enhances our understanding of genetic characteristics of B. anthracis in China.

Feasibility and safety of three periprocedure anticoagulation therapy in patients over 75 years ;undergoing radiofrequency ablation for atrial ifbrillation / 中国介入心脏病学杂志

Objective To observe the safety and efficacy of different periprocedural anticoagulation strategies in patients undergoing catheter ablation of atrial ifbrillation. Methods Eighty-five patients aged over 75 undergoing catheter ablation of atrial fibrillation from Jul 2011 to Nov 2013 were enrolled. They all took warfarin and transesophageal echocardiograms were performed to rule out left atrium appendage thrombus before ablation. They were divided into 3 groups. In Group 1 (30 cases), warfarin was stopped and bridged with low molecular weight heparin (LMWH) 3 days before procedure and LMWH bridging followed by warfarin alone after procedure. In Group 2 (32 cases), warfarin was continued during periprocedural period. In Group 3 (23 cases), Dabigatran or Rivaroxaban alone was used 4 hours after procedure respectively. Unfractionated heparin was used during procedure in all three groups. These three anticoagulation strategies were compared in bleeding, embolism events and other complications during 3-month follow-up. Results In Group 1, there were 1 new-onset ischemic stroke during hospitalization, 7 lower extremity hematomas, 1 subdural hemorrhage during 3-month follow-up and 6 minor bleeding events. In Group 2, there were 4 lower extremity hematomas and 4 minor bleeding events during 3-month follow-up. As for Group 3, only 2 lower extremity hematomas during hospitalization was observed in each without any minor bleeding events during follow-up. Conclusions Catheter ablation in elderly atrial ifbrillation patients was safe and effective in general. Compared with traditional anticoagulation strategy, continuing warfarin or novel oral anticoagulants could reduce bleeding complications without increasing thromboembolism risk.

Animal experimental study of biodegradable magnesium alloy stapler for gastrointestinal anastomosis / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To explore the safety and feasibility of biodegradable magnesium alloy stapler based on the result of animal experimental study for gastrointestinal anastomosis.</p><p><b>METHODS</b>Sixteen beagle dogs were equally and randomly divided into experimental (magnesium alloy) group and control (titanium alloy) group. A gastrojejunal and a colonic anastomosis were performed in each beagle dog. The anastomosis time, postoperative complications, body weight, blasting pressure of anastomosis and serum glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, creatinine, blood urea nitrogen, and serum magnesium were compared between the two groups. The healing of anastomosis and degradation of magnesium alloy were observed. The histopathological features of heart, liver, spleen and kidney were examined in the two groups.</p><p><b>RESULTS</b>There were no significant differences in anastomosis time, body weight, postoperative complications, anastomotic bursting pressure between the two groups. The anastomosis was healed well, and no dramatic inflammatory cell infiltration was observed. Magnesium alloy could be degraded completely in the animal body within 90 days. There were no significant differences in serum glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, creatinine, blood urea nitrogen and serum magnesium between the two groups. Histopathological examination showed that the degradation of magnesium alloy did not harm the important organs (liver, kidney, heart, brain and spleen).</p><p><b>CONCLUSIONS</b>Magnesium alloy stapler is safe and feasible for gastrointestinal anastomosis in beagle dogs. The degradation of magnesium alloy does not harm the healing of anastomosis and other important organs. Magnesium alloy stapler may be a candidate of biodegradable and safe material of stapler for gastrointestinal anastomosis in human.</p>

Surgical treatment for recurrent lumbar disc herniation / 中国矫形外科杂志

[Objective]To investigate the surgical treatment of recurrent lumbar disc herniation. [Methods]A total of 17 patients with recurrent lumbar disc herniation were grouped into stable,unstable and severe unstable groups according to the dynamic X-ray film. Patients in stable group and unstable group were treated with open-window discectomy, and those of severe unstable group were treated with full laminectomy, decompression, pedicle screw fixation and fusion. JOA and VAS system were used to follow up before and after operation. Statistic analysis was performed between the stable and unstable groups in pain score and recovery rate.[Results]All the patients were followed up for 3 month to 3 years. The average JOA score was 4.94 before operation, and 12.18 at follow-up,with an average recovery rate of 71.74%. There was no statistic difference between stable group and unstable group in recovery rate.[Conclusion]For patients with spinal instability and chief complaint of leg symptom, reoperative treatment for recurrent lumbar disc herniation can be done with open-window discectomy which may offer good outcome.

Relevant factors and preventive strategy for recurrent lumbar disc herniation / 中国矫形外科杂志

[Objective]To analyze and evaluate the relevant factors of recurrent lumbar disc herniation for providing strategy of prevention of this syndrome.[Method]Sixteen cases of recurrent lumbar disc herniation were analyzed according to medical history,physical examination and image examination before re-operation and the primary operation,and all the patients received exploration during operation.[Result]The relevant factors of recurrent lumbar disc herniation were as follows:the extent of disc degeneration,the stability of lumbar spine,the time of getting out of bed after primary operation and the weight of the patients.[Conclusion]Besides iatrogenic factors,there are several factors related to recurrent lumbar disc herniation,including the characteristics of disc and lumbar spine,as well as the compliance of patients.To remove these factors is the main preventive strategy of recurrent lumbar disc herniation.

Observation on the Ultrastructure of Liver Cells around Hydatid Cyst / 中国寄生虫学与寄生虫病杂志

Liver tissues around hydatid from 8 patients with cystic echinococcosis were observed by transmission electron microscopy,normal hepatic tissues of 6 cases were used as control.The results demonstrated predominant atrophy and necrosis of hepatocytes.These changes seem to be the major hepatic lesion in cystic echinococcosis.