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1.
Artigo em Inglês | MEDLINE | ID: mdl-32006752

RESUMO

OBJECTIVES: Little attention has been paid to heavy metal resistance (HMR) to pathogenic bacteria with the wide use of heavy metals as feed additives in food animals. Therefore, present study was constructed to investigate the presence of HMR in Escherichia coli and Salmonella, and its correlation with disinfectant resistance genes (DRGs) and antibiotic resistance genes (ARGs). METHODS: The heavy metal resistance genes (HMRGs) of 178 E. coli and 294 Salmonella isolated from chicken farms and retail meats were detected by polymerase chain reaction (PCR). The minimal inhibitory concentrations (MICs) of heavy metals were determined by broth micro-dilution method. The complete-genome of E. coli E308 which had indications of multi-resistance was recovered and assembled using third-generation sequencing. RESULTS: Results showed that frequency of different HMRGs in E. coli and Salmonella ranged 0.60 - 77.0% and 0.30 - 87.1%, respectively. MICs of heavy metals for E. coli and Salmonella ranged widely from ≤ 12.5 mg/L to 1600 mg/L. Moreover, the HMRGs (zntA, arsB, merA, pcoR, pcoA, pcoC and chrA) were found to be significantly associated with one or more DRGs (sugE(c), emrE, mdfA, ydgE/ydgF, qacF, sugE(p) and qacEΔ1) and ARGs (sul1, sul2, sul3, tetA, tetB, tetC, blaTEM, blaSHV and blaCTX) (p < 0.05). CONCLUSIONS: The present study demonstrated that HMRGs were widely present in E. coli and Salmonella isolated from chicken farm and retail meats, and the association between HMRGs with DRGs and ARGs may lead to the co-resistance of heavy metals and other antimicrobials.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31802474

RESUMO

BACKGROUND: Microscopic structures of the ossification centers of the odontoid process were studied from the micro-CT images of the axis, and the potential influence of the ossification centers with different microscopic structures on odontoid process fractures was analyzed. MATERIALS AND METHODS: Eighteen odontoid process specimens were randomly collected and scanned by micro-CT. The obtained images were then input into the software for further observation and measurement. Incomplete absorption of the ossification centers in the base was observed, along with the anatomic structure of the regions with incomplete ossification and structural parameters of the trabecular bones. RESULTS: The microscopic structures of the trabecular bones in the ossification centers in the base of the odontoid process could be clearly visualized from the micro-CT images. Among the 18 odontoid process specimens, 11 specimens were found with incomplete absorption of the ossification centers in the axis, the prevalence reaching up to 61%. Regions with incomplete ossification varied in size and morphology, and their 3D morphology was predominantly oval. Of all structural parameters examined for the trabecular bones, there were only significant differences in the degree of anisotropy (DA) between the regions with incomplete absorption of ossification centers and the average vertebral trabecular bones (P < 0.05). CONCLUSIONS: Incomplete absorption of the ossification centers in the base of the odontoid process is a relatively prevalent condition. The cavitation effect of the trabecular bones may be the primary cause for odontoid process fractures.

3.
Chem Commun (Camb) ; 55(94): 14178-14181, 2019 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-31701963

RESUMO

The design of stimuli-responsive hydrogels is attractive but challenging. A multi-stimuli-responsive chiral metallohydrogel was constructed using a rational approach to design a functional metallohydrogel using chiral organic gelators. The as-synthesized metallohydrogel reported here performed remarkably as a visual sensor for discriminating between (R)-phenylglycinol and (S)-phenylglycinol. Furthermore, the metallohydrogel showed a significant capacity for adsorption and enrichment of Cr(vi) in aqueous solution. Besides this, by utilizing anion-induced transformation, the metallohydrogel could be controllably directed to synthesize different types of chiral metal-organic frameworks.

4.
Am J Trop Med Hyg ; 101(6): 1282-1285, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31642424

RESUMO

Infection caused by invasive Salmonella occurs when Salmonella bacteria, which normally cause diarrhea, enter the bloodstream and spread through the body. We report the dramatic increase in florfenicol-resistant invasive non-typhoidal Salmonella (iNTS) in China between 2007 and 2016. Of the 186 iNTS strains isolated during the study period, 34 were florfenicol resistant, most of which harbored known resistance genes. Florfenicol is exclusively used in veterinary medicine in China, but now florfenicol-resistant iNTS is found in clinical patients. This finding indicates that antimicrobial resistance produced in veterinary medicine can be transmitted to humans, which poses a severe threat to public health.

5.
Infect Drug Resist ; 12: 2885-2897, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31571942

RESUMO

Purpose: Human infections caused by invasive non-typhoidal Salmonella (iNTS) are highly prevalent worldwide. However, data for such infections in China are scarce. This study reports the epidemiology of iNTS in China. Methods: INTS isolates were recovered from blood and other clinical specimens collected during 2007-2016 across five provinces (Shanghai, Xinjiang, Fujian, Guangxi, and Chongqing) in China. Antimicrobial susceptibility was performed using the agar dilution method and molecular epidemiology was performed using standard microbiological techniques. Results: A total of 178 iNTS isolates were recovered from approximately 9700 patient specimens during 2007-2016. The predominant serovars were Salmonella Enteritidis (57/178, 32%), Salmonella Choleraesuis (47/178, 26.4%), and Salmonella Typhimurium (24/178, 13.5%). Up to 50 isolates (28.1%) were from patients who were ≤1 year of age, while 28 (15.7%) were from patients who were ≥60 years. Among these isolates, high rates of resistance to nalidixic acid (114/178, 64%), sulfisoxazole (59%), ciprofloxacin (15.2%), and cefotaxime (8.4%) were found. Moreover, 53.4% (95/178) exhibited multidrug resistance, and 3.9% (7/178) showed co-resistance to third-generation cephalosporins and ciprofloxacin. Steadily increasing numbers of nalidixic acid, cefotaxime, and ciprofloxacin-resistant isolates, but decreasing numbers of multidrug resistance isolates were detected during the study period. Detection of quinolone genes in 114 nalidixic acid-resistant isolates showed that 58.3% (67/114) harbored plasmid-mediated quinolone resistance (PMQR) genes [aac(6´)-Ib-cr, qnrA, qnrB, oqxAB, qepA, qnrS, and qnrD] and 98.2% (112/114) exhibited mutations in quinolone resistance determining regions [gyrA, parC, and parE]. Furthermore, we detected beta-lactamases genes in the ceftriaxone-resistant isolates. The most common were blaTEM-1 (93.3%), followed by blaCTX-M-55 (40%), blaCMY-2 (33.3%), and blaOXA-1 (33.3%). Finally, a range of pulsed-field gel electrophoresis patterns were detected among the Salmonella Enteritidis and Salmonella Typhimurium isolates. Conclusion: High rates of multidrug resistance and steadily increasing cefotaxime and ciprofloxacin-resistant iNTS could pose a significant challenge for the effective treatment of salmonellosis in China.

6.
Microorganisms ; 7(6)2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31146495

RESUMO

Although spice extracts are well known to exhibit antibacterial properties, there is lack of a comprehensive evaluation of the antibacterial effect of spices against antibiotic-resistant bacteria. In the present study, ethanolic extracts from a total of 67 spices were comprehensively investigated for their in vitro antibacterial activities by agar well diffusion against two common food-borne bacteria, Staphylococcus aureus and Salmonella enteritidis, with multi-drug resistance. Results showed that S. aureus was generally more sensitive to spice extracts than S. enteritidis. Of the 67 spice extracts, 38 exhibited antibacterial activity against drug-resistant S. aureus, while only four samples were effective on drug-resistant S. enteritidis. In addition, 11 spice extracts with inhibition zones greater than 15 mm were further verified for their broad-spectrum antibacterial properties using another 10 drug-resistant S. aureus strains. It was found that five spice extracts, including galangal, fructus galangae, cinnamon, yellow mustard seed, and rosemary, exhibited the highest antibacterial capacity. Further cytotoxicity of these 11 spices was determined and LC50 values were found to be more than 100 µg/mL except for galangal, rosemary, and sage, whose LC50 values were 9.32 ± 0.83, 19.77 ± 2.17, and 50.54 ± 2.57, respectively. Moreover, the antioxidant activities (ferric-reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) values) and total phenolic content (TPC) of spice extracts were determined to establish possible correlations with the antibacterial activity. Although the antibacterial effect was positively correlated with the antioxidant activities and TPC, the correlation was weak (r < 0.5), indicating that the antibacterial activity could also be attributed to other components besides antioxidant polyphenols in the tested spice extracts. In conclusion, dietary spices are good natural sources of antibacterial agents to fight against antibiotic-resistant bacteria, with potential applications as natural food preservatives and natural alternatives to antibiotics in animal feeding.

7.
Gut Pathog ; 11: 30, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31198443

RESUMO

Background: Internalins are surface proteins that are utilized by Listeria monocytogenes to facilitate its invasion into human intestinal epithelial cells. The expression of a full-length InlA is one of essential virulence factors for L. monocytogenes to cross the intestinal barrier in order to invade epithelial cells. Results: In this study, the gene sequences of inlA in 120 L. monocytogenes isolates from food (n = 107) and humans (n = 13) were analyzed. Premature stop codon (PMSC) mutations in inlA were identified in 51 isolates (50 from food and 1 from human). Six mutation types of PMSCs were identified. Among the 51 isolates with PMSCs in inlA, there were 44 serogroup 1/2c, 3c isolates from food, of which seven belonged to serogroups 1/2a, 3a. A total of 153,382 SNPs in 2247 core genes from 42 genomes were identified and used to construct a phylogenetic tree. Serotype 1/2c isolates with inlA PMSC mutations were grouped together. Cell culture studies on 21 isolates showed that the invasion to Caco-2 cells was significantly reduced among isolates with inlA PMSC mutations compared to those without PMSC mutations (P < 0.01). The PMSC mutations in inlA correlated with the inability of the L. monocytogenes isolates to invade Caco-2 cells (Pearson's coefficient 0.927, P < 0.01). Conclusion: Overall, the study has revealed the reduced ability of L. monocytogenes to invade human intestinal epithelial cells in vitro was linked to the presence of PMSC mutations in inlA. Isolates with PMSC mutations shared the same genomic characteristics indicating the genetic basis on the potential virulence of L. monocytogenes invasion.

8.
BMC Microbiol ; 19(1): 116, 2019 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142259

RESUMO

BACKGROUND: Shigella spp., facultative anaerobic bacilli of the family Enterobacteriaceae, are one of the most common causes of diarrheal diseases in human worldwide which have become a significant public health burden. So, we aimed to analyze the antimicrobial phenotypes and to elucidate the molecular mechanisms underlying resistance to cephalosporins and fluoroquinolones in Shigella isolates from patients with diarrhea in Shanxi Province. RESULTS: During 2006-2016, we isolated a total of 474 Shigella strains (including 337 S. flexneri and 137 S. sonnei). The isolates showed high rates of resistance to traditional antimicrobials, and 26, 18.1 and 3.0% of them exhibited resistance to cephalosporins, fluoroquinolones and co-resistance to cephalosporins and fluoroquinolones, respectively. Notably, 91.1% of these isolates, including 22 isolates that showed an ACTSuT profile, exhibited multidrug resistance (MDR). The resistance rates to cephalosporins in S. sonnei isolates were higher than those in S. flexneri. Conversely, the resistance rates to fluoroquinolones were considerably higher in S. flexneri isolates. Among the 123 cephalosporins-resistant isolates, the most common extended-spectrum beta-lactamase gene was blaTEM-1, followed by blaCTX-M, blaOXA-1, and blaSHV-12. Six subtypes of blaCTX-M were identified, blaCTX-M-14 (n = 36) and blaCTX-M-55 (n = 26) were found to be dominant. Of all the 86 isolates with resistance to fluoroquinolones and having at least one mutation (Ser83Leu, His211Tyr, or Asp87Gly) in the the quinolone resistance-determining regions of gyrA, 79 also had mutation of parC (Ser80Ile), whereas 7 contained plasmid-mediated quinolone resistance genes including qnrA, qnrB, qnrS, and aac(60)-Ib-cr. Furthermore, pulsed-field gel electrophoresis analysis (PFGE) showed a considerable genetic diversity in S. flexneri isolates. However, the S. sonnei isolates had a high genetic similarity. CONCLUSIONS: Coexistence of diverse resistance genes causing the emergence and transmission of MDR might render the treatment of shigellosis difficult. Therefore, continuous surveillance might be needed to understand the actual disease burden and provide guidance for shigellosis.

9.
PLoS One ; 14(4): e0209083, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30986209

RESUMO

An extreme learning machine (ELM) is a novel training method for single-hidden layer feedforward neural networks (SLFNs) in which the hidden nodes are randomly assigned and fixed without iterative tuning. ELMs have earned widespread global interest due to their fast learning speed, satisfactory generalization ability and ease of implementation. In this paper, we extend this theory to hypercomplex space and attempt to simultaneously consider multisource information using a hypercomplex representation. To illustrate the performance of the proposed hypercomplex extreme learning machine (HELM), we have applied this scheme to the task of multispectral palmprint recognition. Images from different spectral bands are utilized to construct the hypercomplex space. Extensive experiments conducted on the PolyU and CASIA multispectral databases demonstrate that the HELM scheme can achieve competitive results. The source code together with datasets involved in this paper can be available for free download at https://figshare.com/s/01aef7d48840afab9d6d.


Assuntos
Dermatoglifia , Aprendizado de Máquina , Adulto , Algoritmos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reconhecimento Automatizado de Padrão/métodos , Adulto Jovem
10.
EBioMedicine ; 42: 133-144, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30905850

RESUMO

BACKGROUND: Colistin resistance mediated by mcr-1-harbouring plasmids is an emerging threat in Enterobacteriaceae, like Salmonella. Based on its major contribution to the diarrhoea burden, the epidemic state and threat of mcr-1-harbouring Salmonella in community-acquired infections should be estimated. METHODS: This retrospective study analysed the mcr-1 gene incidence in Salmonella strains collected from a surveillance on diarrhoeal outpatients in Shanghai Municipality, China, 2006-2016. Molecular characteristics of the mcr-1-positive strains and their plasmids were determined by genome sequencing. The transfer abilities of these plasmids were measured with various conjugation strains, species, and serotypes. FINDINGS: Among the 12,053 Salmonella isolates, 37 mcr-1-harbouring strains, in which 35 were serovar Typhimurium, were detected first in 2012 and with increasing frequency after 2015. Most patients infected with mcr-1-harbouring strains were aged <5 years. All strains, including fluoroquinolone-resistant and/or extended-spectrum ß-lactamase-producing strains, were multi-drug resistant. S. Typhimurium had higher mcr-1 plasmid acquisition ability compared with other common serovars. Phylogeny based on the genomes combined with complete plasmid sequences revealed some clusters, suggesting the presence of mcr-1-harbouring Salmonella outbreaks in the community. Most mcr-1-positive strains were clustered together with the pork strains, strongly suggesting pork consumption as a main infection source. INTERPRETATION: The mcr-1-harbouring Salmonella prevalence in community-acquired diarrhoea displays a rapid increase trend, and the ESBL-mcr-1-harbouring Salmonella poses a threat for children. These findings highlight the necessary and significance of prohibiting colistin use in animals and continuous monitoring of mcr-1-harbouring Salmonella.


Assuntos
Diarreia/epidemiologia , Diarreia/microbiologia , Genes Bacterianos , Genoma Bacteriano , Pacientes Ambulatoriais , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Salmonella/genética , Antibacterianos/farmacologia , Criança , Pré-Escolar , China/epidemiologia , Diarreia/história , Feminino , Genômica/métodos , História do Século XXI , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Tipagem Molecular , Filogenia , Plasmídeos/genética , Vigilância em Saúde Pública , Salmonella/classificação , Salmonella/efeitos dos fármacos , Infecções por Salmonella/história , Sorogrupo
11.
J Cell Mol Med ; 23(5): 3108-3117, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30843345

RESUMO

Glioblastoma (GBM) is the most prevalent primary malignancy of the central nervous system with obvious aggressiveness, and is associated with poor clinical outcome. Studies have indicated that calcium ion (Ca2+ ) can positively regulate the initiation of malignancy with regard to GBM by modulating quiescence, proliferation, migration and maintenance. Hippocalcin like-1 protein (HPCAL1) serves as a sensor of Ca2+ . However, the understanding of HPCAL1 activity in GBM is limited. The present study revealed that the gene HPCAL1 was up-regulated by Ca2+ in the tissues and cells of GBM. Ectopic expression of HPCAL1 promoted proliferation of cells. Exhaustion of HPCAL1 inhibited cell growth not only in vivo, but also in vitro. In addition, HPCAL1 enhanced the Wnt pathway by stimulating ß-catenin accumulation and nuclear translocation in GBM cells, while ß-catenin silencing significantly inhibited the proliferation and growth of the GBM cells. Our results showed that Ser9 phosphorylation of GSK3ß was significantly decreased after HPCAL1 knockdown in GBM cells, and knockdown of the gene GSK3ß in GBM cells enhanced cell proliferation and promoted transcription of the genes CCND1 and c-Myc. Furthermore, the phosphorylation of ERK was decreased in the cells with HPCAL1 knockdown, while it was promoted via overexpression of HPCAL1. The suppression or depletion of the gene ERK decreased proliferation triggered by overexpression of HPCAL1 and impaired transcription of the genes c-Myc and CCND1. These studies elucidate the tumour-promoting activity of HPCAL1. They also offer an innovative therapeutic strategy focusing on the HPCAL1-Wnt/ß-catenin axis to regulate proliferation and development of GBM.

12.
Foodborne Pathog Dis ; 16(4): 244-255, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30779595

RESUMO

OBJECTIVES: This study aimed to trace the transmission source of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis strains associated with enteric infections in Shanghainese children, and understand the molecular mechanism of resistance to third-generation cephalosporins and ciprofloxacin. MATERIALS AND METHODS: The profiles of pulsed-field gel electrophoresis (PFGE) were compared among the isolates from children, animal, and environment. Antimicrobial susceptibility was determined using the minimal inhibitory concentrations and Kirby-Bauer disk diffusion method. Extended-spectrum ß-lactamase (ESBL) producing isolates mediated by resistance genes were identified using polymerase chain reaction and sequencing. RESULTS: Based on PFGE patterns, 49 (33.1%) of 148 human Salmonella Typhimurium isolates located in the dominant PFGE clusters were genetically related to the isolates from poultry source, environment water, aquatic products, and reptiles, whereas 97 (97.0%) of 100 human Salmonella Enteritidis isolates were genetically related to isolates from poultry and water. The rates of resistance to ceftriaxone among clinical Salmonella Typhimurium and Salmonella Enteritidis isolates were 42.0% and 14.2%, respectively. Besides, 35.1% of Salmonella Typhimurium isolates displayed resistance to ciprofloxacin; 64.9% of Salmonella Typhimurium isolates and 97.0% of Salmonella Enteritidis isolates displayed reduced susceptibility to ciprofloxacin. Of 64 ESBL/AmpC-producing strains, CTX-M, TEM, DHA, and CMY were detected at frequencies of 86.0%, 62.5%, 7.8%, 3.1%, and 3.1%, respectively. CONCLUSIONS: The transmission sources of Salmonella Typhimurium and Salmonella Enteritidis infections in Shanghainese children were diverse. The high prevalence of resistance to third-generation cephalosporins and ciprofloxacin mediated by multiple molecular mechanisms needs continuous monitoring and intervention.

13.
Sensors (Basel) ; 19(2)2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30634530

RESUMO

For the past decades, recognition technologies of multispectral palmprint have attracted more and more attention due to their abundant spatial and spectral characteristics compared with the single spectral case. Enlightened by this, an innovative robust L2 sparse representation with tensor-based extreme learning machine (RL2SR-TELM) algorithm is put forward by using an adaptive image level fusion strategy to accomplish the multispectral palmprint recognition. Firstly, we construct a robust L2 sparse representation (RL2SR) optimization model to calculate the linear representation coefficients. To suppress the affection caused by noise contamination, we introduce a logistic function into RL2SR model to evaluate the representation residual. Secondly, we propose a novel weighted sparse and collaborative concentration index (WSCCI) to calculate the fusion weight adaptively. Finally, we put forward a TELM approach to carry out the classification task. It can deal with the high dimension data directly and reserve the image spatial information well. Extensive experiments are implemented on the benchmark multispectral palmprint database provided by PolyU. The experiment results validate that our RL2SR-TELM algorithm overmatches a number of state-of-the-art multispectral palmprint recognition algorithms both when the images are noise-free and contaminated by different noises.

14.
Transbound Emerg Dis ; 66(2): 1044-1048, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30548172

RESUMO

Salmonella enterica Newport (S. Newport), with phylogenetic diversity feature, contributes to significant public health concerns. Our previous study suggested that S. Newport from multiple animal-borne routes, with distinct antibiotic resistant pattern, might transmit to human. However, their genetic information was lacking. As a complement to the earlier finding, we investigate the relationship between each other among the hosts, sources, genotype and antibiotic resistance in S. Newport. We used the multilocus sequence typing (MLST) in conjunction with minimum inhibitory concentration of 16 antibiotics of globally sampled 1842 S. Newport strains, including 282 newly contributed Chinese strains, to evaluate this association. Our analysis reveals that sequence types (STs) are significantly associated with different host sources, including livestock (ST45), birds (ST5), contaminated water and soil (ST118), reptiles (ST46) and seafood (ST31). Importantly, ST45 contained most of (344/553) the multi-drug resistance (MDR) strains, which were believed to be responsible for human MDR bacterial infections. Chinese isolates were detected to form two unique lineages of avian (ST808 group) and freshwater animal (ST2364 group) origin. Taken together, genotyping information of S. Newport could serve to improve Salmonella source-originated diagnostics and guide better selection of antibiotic therapy against Salmonella infections.


Assuntos
Salmonelose Animal/epidemiologia , Infecções por Salmonella/epidemiologia , Salmonella enterica/genética , Salmonella enterica/isolamento & purificação , Animais , Farmacorresistência Bacteriana Múltipla , Genes Bacterianos , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Filogenia , Infecções por Salmonella/microbiologia , Salmonelose Animal/microbiologia , Sorogrupo
15.
Foodborne Pathog Dis ; 15(12): 770-775, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30489150

RESUMO

Salmonella producing ß-lactamases has spread rapidly worldwide and poses a serious threat to human and animal health. In this study, we characterized 220 ceftriaxone (CRO)-resistant isolates identified among 3153 Salmonella from humans, animals, food, and water collected in Shanghai, China. They were assessed for antimicrobial susceptibility, phenotypic identification of extended-spectrum ß-lactamases (ESBLs), and ß-lactamase genes and integrons. CRO resistance in Salmonella increased from 5.0% in 2011 to 8.4% in 2013. Salmonella Enteritidis (45.5%), Salmonella Typhimurium (20.9%) from humans, and Salmonella Indiana (14.5%) from poultry represented the majority of the CRO-resistant isolates. Many isolates were also resistant to other antimicrobials, including nalidixic acid (84.5%), sulfisoxazole (70.5%), and tetracycline (61.8%). Resistance to ciprofloxacin was also found in 33.6% of the isolates. Most isolates (98.2%) were confirmed as ESBL producers. Resistance genes such as blaCTX-M, blaTEM, and blaOXA were detected in 207 (94.1%), 99 (45%), and 53 (24.1%) isolates, respectively. Three types of integron I and one type of integron II were identified in 13 (5.9%) and 2 (0.9%) isolates, respectively. The integrons encompassed 10 different genes: dfrA1/12/17/25, aadA1/2/5, sat2, orfF, and ybeA. Our study underscores concern for increasing CRO resistance, and highlights the widespread ESBL genes in Salmonella enterica.


Assuntos
Antibacterianos/farmacologia , Ceftriaxona/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Salmonella enterica/genética , beta-Lactamases/genética , Animais , China , Microbiologia de Alimentos , Humanos , Integrons/genética , Carne/microbiologia , Testes de Sensibilidade Microbiana , Aves Domésticas/microbiologia , Rios/microbiologia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/enzimologia , Suínos/microbiologia
16.
Front Microbiol ; 9: 2492, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30405560

RESUMO

Diverse mobile genetic elements (MGEs) including plasmids, insertion sequences, and integrons play an important role in the occurrence and spread of multidrug resistance (MDR) in bacteria. It was found in previous studies that IS26 and class 1 integrons integrated on plasmids to speed the dissemination of antibiotic-resistance genes in Salmonella. It is aimed to figure out the patterns of specific genetic arrangements between IS26 and class 1 integrons located in plasmids in MDR Salmonella in this study. A total of 74 plasmid-harboring Salmonella isolates were screened for the presence of IS26 by PCR amplification, and 39 were IS26-positive. Among them, 37 isolates were resistant to at least one antibiotic. The thirty-seven antibiotic-resistant isolates were further involved in PCR detection of class 1 integrons and variable regions, and all were positive for class 1 integrons. Six IS26-class 1 integron arrangements with IS26 inserted into the upstream or downstream of class 1 integrons were characterized. Eight combinations of these IS26-class 1 integron arrangements were identified among 31 antibiotic-resistant isolates. Multidrug-resistance plasmids of the IncHI2 incompatibility group were dominant, which all belonged to ST3 by plasmid double locus sequence typing. These 21 IncHI2-positive isolates harbored six complex IS26-class 1 integron arrangement patterns. Conjugation assays and Southern blot hybridizations confirmed that conjugative multidrug-resistance IncHI2 plasmids harbored the different complex IS26-class 1 integron arrangements. The conjugation frequency of IncHI2 plasmids transferring alone was 10-5-10-6, reflecting that different complex IS26-class 1 integron arrangement patterns didn't significantly affect conjugation frequency (P > 0.05). These data suggested that class 1 integrons represent the hot spot for IS26 insertion, forming diverse MDR loci. And ST3-IncHI2 was the major plasmid lineage contributing to the horizontal transfer of composite IS26-class 1 integron MDR elements in Salmonella.

17.
Int J Food Microbiol ; 286: 190-196, 2018 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-30268051

RESUMO

In this study, 2887 Salmonella strains were mainly obtained from patients and foods in Shanghai from 2006 to 2014 in order to assess the susceptibility to 16 antibiotics. Among them, 3.8% (110/2887) S. Enteritidis isolates were shown to have an ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline) resistance pattern. The resistance genes of ACSSuT included sul2 (74.55%), flo (67.27%), tetA (49.09%), and aph(3)-IIa (46.36%). In addition, class 1 integron profiles were detected in 9 isolates, and 55.6% (5/9) were shown to carry resistant genes against aminoglycosides and sulfonamides. Moreover, these isolates had a high rate of resistance to nalidixic acid (95.29%), cefotaxime (70.64%), cefepime (58.72%), and ceftazidime (48.62%). Detection of quinolone genes showed that 93.64% (103/110) of the strains had gyrA single mutations (D87G, D87Y, D87N, S83Y, and S83F), where D87G was the dominant mutation in 55.45% isolates. 19.1% (21/110) isolates carried plasmid-mediated quinolone resistance (PMQR) genes (qnrB and aac(6')-Ib-cr), and the most prevalent was qnrB. Furthermore, we also detected ESBLS genes. The most common were blaCTX-M-55 (57.27%) followed by blaTEM (23.6%) and blaOXY (4.55%). Mart, prot6E, steB, fimA, and sopE2 genes (100%) were the most in these isolates. The strains in the dominant PFGE profiles of G1 were all co-resistant to quinolones, cephalosporins, and ACSSuT, and were isolated from different sources. This suggests that existence of these genes lead to the emergence of high-levels of resistance to quinolone and cephalosporin in these ACSSuT resistance pattern isolates. And these isolates are transmitted between humans and food.


Assuntos
Antibacterianos/farmacologia , Cefalosporinas/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Quinolonas/farmacologia , Salmonella enteritidis , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Galinhas , Criança , Pré-Escolar , China , Feminino , Microbiologia de Alimentos , Humanos , Lactente , Recém-Nascido , Integrons/genética , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Plasmídeos/genética , Carne Vermelha/microbiologia , Salmonella enteritidis/efeitos dos fármacos , Salmonella enteritidis/genética , Salmonella enteritidis/isolamento & purificação , Adulto Jovem , beta-Lactamases/genética
18.
Front Microbiol ; 9: 2111, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30245675

RESUMO

Salmonellaenterica serovar Enteritidis (Salmonella Enteritidis) is a globally important foodborne pathogen, and the contaminated chicken eggs are the major source of salmonellosis in humans. Salmonella Enteritidis strains are differentially susceptible to the hostile environment of egg whites. Strains with superior survival ability in egg whites are more likely to contaminate eggs and consequently infect humans. However, the genetic basis for this phenotype is unclear. We characterized two Salmonella Enteritidis strains isolated from chicken meat that had similar genetic backgrounds but large differences in survival ability in egg whites. Although genome comparisons indicated that the gene content and genomic synteny were highly conserved, variations including six insertions or deletions (INDELs) and 70 single nucleotide polymorphisms (SNPs) were observed between the two genomes. Of these, 38 variations including four INDELs and 34 non-synonymous SNPs (nsSNP) were annotated to result in amino acid substitutions or INDELs in coding proteins. These variations were located in 38 genes involved in lysozyme inhibition, vitamin biosynthesis, cell division and DNA damage response, osmotic and oxidative protection, iron-related functions, cell envelope maintenance, amino acid and carbohydrate metabolism, antimicrobial resistance, and type III secretion system. We carried out allelic replacements for two nsSNPs in bioC (biotin synthesis) and pliC (lysozyme inhibition), and two INDELs in ftsK and yqiJ (DNA damage response) by homologous recombination, and these replacements did not alter the bacterial survival ability in egg whites. However, the bacterial survival ability in egg whites was reduced when deletion mutation of the genes bioC and pliC occurred. This study provides initial correlations between observed genotypes and phenotypes and serves as an important caveat for further functional studies.

19.
Front Microbiol ; 9: 1642, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30108555

RESUMO

Emerging resistance to the antimicrobial agents of choice for treatment of thermophilic Campylobacter infections is becoming a serious threat to public health. In this study, 548 Campylobacter (372 C. jejuni and 176 C. coli) isolates from diarrheal patients and poultry meat were subjected for antibiotic susceptibility analysis to ciprofloxacin, tetracycline, gentamicin, erythromycin and clindamycin. Among them, 151 Campylobacter (32 C. jejuni and 119 C. coli) were identified as multidrug resistant isolates. PFGE analysis was performed on the 151 multidrug resistant isolates to determine their genetic relatedness, and 103 PFGE genotypes were determined. Some isolates from both human and chicken belonged to identical genotypes, indicating these clones might be able to spread between human and chicken. Antibiotic resistant genes of the 151 isolates were identified. The numbers of isolates carried tet (O), aadE, ermB, and aadE-sat4-aphA were 148 (98%), 89 (58.9%), 31 (20.5%), and 10 (6.6%), respectively. Almost all (n = 150, 99.3%) had gyrA mutation at codon 86. And the 23s rRNA A2075G point mutation was found in 56 (37.1%) isolates. Gene mutations at the cmeR-cmeABC intergenic region may lead to the activation of CmeABC multidrug efflux pump, and in this study novel sequence types of the intergenic region were identified in both C. jejuni and C. coli. This study determined the genetic prerequisites for antibiotic resistance of multidrug resistant Campylobacter isolates from diarrheal patients and poultry meat in Shanghai, China.

20.
Rev Sci Instrum ; 89(7): 074302, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30068128

RESUMO

Brain-computer interface (BCI) systems establish a direct communication channel from the brain to an output device. As the basis of BCIs, recognizing motor imagery activities poses a considerable challenge to signal processing due to the complex and non-stationary characteristics. This paper introduces an optimal and intelligent method for motor imagery BCIs. Because of the robustness to noise, wavelet packet decomposition and common spatial pattern (CSP) methods were implemented to reduce the dimensions of preprocessed signals. And a novel and efficient classifier projection extreme learning machine (PELM) was employed to recognize the labels of electroencephalogram signals. Experiments have been performed on the BCI Competition Dataset to demonstrate the superiority of wavelet-CSP in BCI and the outperformance of the PELM-based method. Results show that the average recognition rate of PELM approaches approximately 70%, while the optimal rate of other methods is 72%, whose training time and classification time are relatively longer as 11.00 ms and 11.66 ms, respectively, compared with 4.75 ms and 4.87 ms obtained by using the proposed BCI system.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Imaginação/fisiologia , Aprendizado de Máquina , Atividade Motora/fisiologia , Análise de Ondaletas , Encéfalo/fisiologia , Calibragem , Eletroencefalografia/métodos , Humanos , Reconhecimento Automatizado de Padrão/métodos , Análise de Componente Principal , Fatores de Tempo
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