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1.
MMWR Morb Mortal Wkly Rep ; 68(33): 713-717, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31437141

RESUMO

In September 2018, CDC identified Salmonella enterica serotype Newport (Newport) infections that were multidrug resistant (MDR), with decreased susceptibility to azithromycin, a recommended oral treatment agent. Until 2017, decreased susceptibility to azithromycin had occurred in fewer than 0.5% of Salmonella isolates from U.S. residents. This report summarizes the investigation of a multistate MDR Salmonella outbreak conducted by CDC, state and local health departments, and the U.S. Department of Agriculture's Food Safety and Inspection Service. During June 2018-March 2019, 255 cases of infection with the outbreak strain were identified in 32 states; 43% of patients (89 of 206 with information on travel) reported recent travel to Mexico. Infections were linked to consumption of soft cheese obtained in Mexico and beef obtained in the United States. Consumers should avoid eating soft cheese that could be made from unpasteurized milk, regardless of the source of the cheese. When preparing beef, a food thermometer should be used to ensure that appropriate cooking temperatures are reached. When antibiotic treatment is needed for a patient, clinicians should choose antibiotics based on susceptibility testing wherever possible.


Assuntos
Azitromicina/farmacologia , Surtos de Doenças , Farmacorresistência Bacteriana Múltipla , Intoxicação Alimentar por Salmonella/epidemiologia , Salmonella/efeitos dos fármacos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Queijo/microbiologia , Criança , Pré-Escolar , Feminino , Microbiologia de Alimentos , Humanos , Lactente , Masculino , México , Pessoa de Meia-Idade , Carne Vermelha/microbiologia , Salmonella/genética , Intoxicação Alimentar por Salmonella/tratamento farmacológico , Doença Relacionada a Viagens , Estados Unidos/epidemiologia , Adulto Jovem
2.
J Agric Food Chem ; 67(33): 9390-9398, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31365249

RESUMO

Various pathogens may coexist in one sample; however, detection methods that rely on traditional selective culture media or immune agents designed specifically for a certain target are unsuitable for multiple targets. It is important to develop a simultaneous and sensitive detection method for multiple pathogens. Here, a multicolor and ultrasensitive enzyme-linked immunosorbent assay (ELISA) platform based on the fluorescence hybridization chain reaction (HCR) was developed. In the assay, multicolor fluorescence concatemers formed as signal amplifiers and signal reporters in the presence of target pathogens. When HCR occurred, Escherichia coli O157:H7, Salmonella serotype Choleraesuis, and Listeria monocytogenes were detected simultaneously with three different fluorescences. Additionally, the limits of detection for E. coli O157:H7, Salmonella Choleraesuis, and L. monocytogenes were 3.4 × 101, 6.4 × 100, and 7.0 × 101 CFU/mL, respectively. The assay achieved ultrasensitive, specific, and simultaneous detection of three pathogens and can be applied to the detection of pathogens in milk samples. Therefore, this multicolor and ultrasensitive ELISA platform has great potential in the application of simultaneous detection of pathogens.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Escherichia coli O157/isolamento & purificação , Listeria monocytogenes/isolamento & purificação , Leite/microbiologia , Salmonella/isolamento & purificação , Animais , Bovinos , Ensaio de Imunoadsorção Enzimática/instrumentação , Fluorescência , Microbiologia de Alimentos , Sensibilidade e Especificidade
3.
Rev Inst Med Trop Sao Paulo ; 61: e36, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31340248

RESUMO

During the last years, Brazilian government control programs have detected an increase of Salmonella Heidelberg in poultry slaughterhouses a condition that poses a threat to human health However, the reasons remain unclear. Differences in genetic virulence profiles may be a possible justification. In addition, effective control of Salmonella is related to an efficient epidemiological surveillance system through genotyping techniques. In this context, the aim of this study was the detection of 24 virulence-associated genes in 126 S. Heidelberg isolates. We classified the isolates into 56 different genetic profiles. None of the isolates presented all the virulence genes. The prevalence of these genes was high in all tested samples as the lowest number of genes detected in one isolate was 10/24. The lpfA and csgA (fimbriae), invA and sivH (TTSS), and msgA and tolC (intracellular survival) genes were present in 100% of the isolates analyzed. Genes encoding effector proteins were detected in the majority of SH isolates. No single isolate had the sefA gene. The pefA gene was found in only four isolates. We have also performed a screening of genes associated with iron metabolism: 88.9% of isolates had the iroN geneand 79.4% the sitC gene . Although all the isolates belong to the same serotype, several genotypic profiles were observed. These findings suggest that there is a diversity of S. Heidelberg isolates in poultry products. The fact that a single predominant profile was not found in this study indicates the presence of variable sources of contamination caused by SH. The detection of genetic profiles of Salmonella strains can be used to determine the virulence patterns of SH isolates.


Assuntos
Doenças das Aves Domésticas/microbiologia , Produtos Avícolas/microbiologia , Salmonelose Animal/microbiologia , Salmonella/genética , Salmonella/patogenicidade , Fatores de Virulência/genética , Virulência/genética , Animais , Microbiologia de Alimentos , Genótipo , Reação em Cadeia da Polimerase
4.
Vet Microbiol ; 233: 118-123, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31176397

RESUMO

The vast capacity for maintenance and dissemination in the environment are major challenges for the control of Salmonella spp. in poultry farms. The aim of this study was to assess environmental contamination by non-typhoidal Salmonella in successive broiler flocks in nine commercial broiler farms integrated with three companies in the south of Brazil, for a twelve-month production period. Recycled broiler litter, feed and swabs from the evaporative cooling system pads were analyzed, and the total enterobacteria count in the litter samples was ascertained. Positive broiler houses were identified in two of the three broiler companies studied, in which non-typhoidal Salmonella were detected for the first time in the first or second flock, and recurred in the recycled litter of subsequent flocks. Feed and evaporative cooling pad swab samples were also positive in at least one of the assessed flocks. The majority of the isolates (87.5%) originating from different flocks, broiler houses and companies that were sampled were identified as S. Heidelberg, with the prevalence of one single genotype. The total enterobacteria levels in the litter diminished as the flocks progressed, but the presence of Salmonella spp. was constant over the course of time, indicating that the litter management procedures were not capable of interrupting the cycle of residual contamination. The predominance of S. Heidelberg highlights its emergence and dissemination in this region, as well as its resistance and maintenance in the environment, and reinforces the need to improve prevention and recycled litter management measures.


Assuntos
Galinhas/microbiologia , Microbiologia Ambiental , Aves Domésticas/microbiologia , Salmonelose Animal/epidemiologia , Salmonella/genética , Criação de Animais Domésticos , Animais , Brasil/epidemiologia , Genótipo , Abrigo para Animais/normas , Estudos Longitudinais , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/prevenção & controle , Prevalência , Salmonella/isolamento & purificação , Sorogrupo
5.
Microbiol Res ; 223-225: 63-71, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178053

RESUMO

The phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) catalyzes the translocation of sugar substrates with their concomitant phosphorylation in bacteria. In addition to its intrinsic role in sugar transport and metabolism, numerous recent studies report the versatility of the PTS to interconnect energy and signal transduction in response to sugar availability. In this study, the role of PTS in Salmonella virulence regulation was explored. To decipher the regulatory network coordinated by the PTS during Salmonella infection, a transcriptomic approach was applied to a transposon insertion mutant with defective expression of ptsI and crr, which encode enzyme I and enzyme IIAGlc of the PTS, respectively. There were 114 differentially expressed genes (DEGs) exhibiting two-fold or higher expression changes in the transposon mutant strain, with 13 up-regulated genes versus 101 down-regulated genes. One-third of the DEGs were associated with energy production and carbohydrate/amino acid metabolism pathways, implicating the prominent role of the PTS in carbohydrate transport. With regard to regulation of virulence, the tested mutant decreased the expression of genes associated with quorum sensing, Salmonella pathogenicity islands, flagella, and the PhoPQ regulon. We investigated the possibility of PTS-mediated regulation of virulence determinants identified in the transcriptomic analysis and proposed a regulatory circuit orchestrated by the PTS in Salmonella infection of host cells. These results suggest that Salmonella divergently controls virulence attributes in accordance with the availability of carbohydrates in the environment.


Assuntos
Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Fosfoenolpiruvato/metabolismo , Fosfotransferases/metabolismo , Salmonella/genética , Salmonella/metabolismo , Fatores de Virulência/genética , Transporte Biológico , Elementos de DNA Transponíveis , Flagelos/genética , Perfilação da Expressão Gênica , Proteínas de Membrana/genética , Mutação , Fosforilação , Regulon , Salmonella/patogenicidade , Infecções por Salmonella , Salmonella typhimurium/genética , Transdução de Sinais , Transcriptoma , Sistemas de Secreção Tipo III/genética , Virulência/genética
6.
Food Chem ; 295: 671-679, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174811

RESUMO

The aim of this work was to develop and optimize a pH-responsive nanoparticle based on poly(D,L-lactide-co-glycolide) (PLGA) and chitosan (CHIT) for delivery of natural antimicrobial using trans-cinnamaldehyde (TCIN) as a model compound. The optimization was performed using a central composite design and the desirability function approach. The optimized levels of variables considering all significant responses were 4% (w/w) of TCIN and 6.75% (w/w) of CHIT. After, optimized nanoparticles were produced and characterized according to their physicochemical properties and their antimicrobial activity against Salmonella Typhimurium and Staphylococcus aureus. Optimized nanoparticles characterization indicated a satisfactory TCIN encapsulation (33.20 ±â€¯0.85%), spherical shape, pH-responsive controlled release, with faster release in the presence of CHIT at low pH, and enhanced antimicrobial activity against both pathogens. TCIN encapsulation using PLGA coated with CHIT enhanced its antimicrobial activity and generated a delivery system with pH-sensitivity for controlled release with promising properties for food safety applications.


Assuntos
Anti-Infecciosos/química , Quitosana/sangue , Nanopartículas/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Acroleína/análogos & derivados , Acroleína/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Varredura Diferencial de Calorimetria , Quitosana/química , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Salmonella/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
7.
Klin Lab Diagn ; 64(6): 368-375, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31200410

RESUMO

Salmonella is one of the leading food-borne infection pathogen: annually in the Russian Federation about 50 thousand cases of salmonellosis are registered. Antimicrobial therapy is necessary in the case of severe infection in children under 6 years and persons over 50 years, in patients with severe accompanying disease, as well as in the case of generalization of the infection. Beta-lactam antibiotics, quinolones and azithromycin are included in the list of drugs recommended for antimicrobial therapy of salmonellosis, including typhoid fever. The effectiveness of therapy largely depends on the appropriate antimicrobial susceptibility testing: the choice of testing method, indicator antibiotics and result interpretation. Salmonella belong to the Enterobacteriacae family and are characterized by common mechanisms of resistance to quinolones and beta-lactams, but antimicrobial susceptibility testing of Salmonella to these groups of antibiotics has a number of features. The article presents current data on the susceptibility of Salmonella, including S. Typhi, to antibiotics and leading clinically significant resistance mechanisms. The methodical aspects of Salmonella antimicrobial susceptibility testing of the drugs used for the treatment of salmonellosis (quinolones, beta-lactams and azithromycin) are described in detail. Interpretation of Salmonella testing results according the modern international and Russian recommendations are presented. The authors propose the algorithms for Salmonella antimicrobial susceptibility testing of quinolones, cephalosporins and carbapenems, as well as criteria for result interpretation, allowing the detection of clinically significant mechanisms of resistance to beta-lactams (production of beta-lactamases of different molecular classes) and quinolones (chromosomal mutations and acquired resistance genes).


Assuntos
Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Salmonella/efeitos dos fármacos , Humanos , Federação Russa
8.
Environ Monit Assess ; 191(7): 456, 2019 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-31230187

RESUMO

The objective of the study was to assess the microbiological safety of popular recreational swimming sites in Central California. Water samples were collected from eleven monitoring sites across the lower reaches of two watersheds for two consecutive swimming seasons (2012-2013), and levels of indicator and pathogenic microorganisms were determined. Data on ambient weather and water chemistry were collected for analyzing their associations with microorganisms in water. All water samples were positive for indicator E. coli with mean concentrations per site ranging from 3.07 to 216.11 MPN/100 ml in 2012 and 13.4 to 226.97 MPN/100 ml in 2013. Mean E. coli concentrations in 27% and 36% samplings sites exceeded the EPA 2012 Recreational Water Quality Criteria recommended mean concentration of ≤ 126 CFU/100 ml of E. coli, in 2012 and 2013, respectively. Cryptosporidium spp. oocysts were detected in all water samples from all sampling sites, with an overall prevalence of 50% and mean concentrations of 0.08 oocysts/l in 2012 and 0.19 oocysts/l in 2013. Giardia spp. cysts were detected at eight sites, with an overall prevalence of 28.8% and mean concentration of 0.2 cysts/l in both years. The majority of the detected Cryptosporidium spp. oocysts and Giardia spp. cysts appeared damaged under microscopy. E. coli O157:H7 was detected in 9% of water samples, with positive samples limited to three sites. Salmonella spp. were detected in all but one site across the two years, with mean concentrations of 0.94 MPN/l in 2012 and 1.85 MPN/l in 2013. Cryptosporidium spp. oocyst concentrations were negatively associated with 30-day mean wind speed and cumulative precipitation and dissolved oxygen in water. Giardia spp. cyst concentrations were positively associated with turbidity and pH of water and negatively associated with E. coli concentrations and 24-h mean air temperature. Salmonella spp. concentrations were positively associated with 30-day mean air temperature. The occurrence of E. coli O157:H7 was positively associated with previous 30-day cumulative precipitation.


Assuntos
Cryptosporidium/isolamento & purificação , Monitoramento Ambiental/métodos , Escherichia coli O157/isolamento & purificação , Giardia/isolamento & purificação , Oocistos/isolamento & purificação , Salmonella/isolamento & purificação , Qualidade da Água , Água/parasitologia , Animais , California , Parques Recreativos , Estações do Ano , Natação , Microbiologia da Água , Tempo (Meteorologia)
9.
Food Chem ; 296: 23-28, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202302

RESUMO

Cronobacter sakazakii and Salmonella spp. are foodborne pathogens associated with low moisture foods. An intense pulsed light (IPL) system is being developed as an alternative novel method to pasteurize powdered food. The aim of the study is to investigate the microorganism inactivation in different powdered foods and a variety of related variables using a vibratory-assisted IPL system. The results showed that C. sakazakii on non-fat dry milk (NFDM), wheat flour, and egg white powder were significantly inactivated by 5.27, 4.92, and 5.30 log10 CFU/g, respectively, after 3 or 4 passes of IPL treatments. For decontamination of E. faecium, 3-4 passes of IPL treatments reduced the E. faecium level on NFDM, wheat flour, and egg white by 3.67, 2.79, 2.74 log10 CFU/g, respectively. These results demonstrated that the enhanced microbiological inactivation can be achieved using this vibratory-assisted IPL system after multiple passes.


Assuntos
Cronobacter sakazakii/efeitos da radiação , Enterococcus faecium/efeitos da radiação , Farinha/microbiologia , Luz , Salmonella/efeitos da radiação , Animais , Cronobacter sakazakii/crescimento & desenvolvimento , Clara de Ovo/microbiologia , Enterococcus faecium/crescimento & desenvolvimento , Microbiologia de Alimentos , Leite/microbiologia , Pós/química , Salmonella/crescimento & desenvolvimento , Temperatura Ambiente
11.
Chemosphere ; 231: 518-527, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31151012

RESUMO

Retene (RET) is the most abundant polycyclic aromatic hydrocarbon (PAH) released upon burning of cellulose, although it is not considered as one of the priority PAHs and is not included for risk assessments by the US Environmental Protection Agency (US-EPA). There are only a few studies concerning the toxic effects of RET. To the best of our knowledge, this study is the first one to examine whether RET, in an environmental concentration, plays a crucial role in the induction of oxidative stress in A549 lung cell line, and its consequence as such as mutagenicity and cell death. Our results revealed that RET was able to significantly decrease cell viability only at 72 h of exposure, increase oxidative stress, mitochondrial membrane potential and mitochondrial contents, leading an increased reactive oxygen species (ROS) production. Mutagenic activity was not detected in Salmonella strains, suggesting that RET does not induce base-pair substitution (TA100), frameshift (TA98 and TA97a) and transition/transversion (TA102) mutations. However, exposure to RET led to a significant increase in micronuclei (MN), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs) frequency, as well as cell death, mainly due to necrosis. Taken together, the results of our study provide new evidence suggesting that RET promotes oxidative stress, contributes to the processes of genomic instability, and favors necrosis. Thus, we highlight the importance of including RET in routine environmental analyses in the future as a potential risk factor involved in complex diseases and carcinogenesis.


Assuntos
Mutagênicos/toxicidade , Estresse Oxidativo , Fenantrenos/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Células A549 , Morte Celular , Humanos , Potencial da Membrana Mitocondrial , Mutagênese , Testes de Mutagenicidade/métodos , Mutação , Hidrocarbonetos Policíclicos Aromáticos/análise , Salmonella/efeitos dos fármacos
12.
Emerg Microbes Infect ; 8(1): 857-865, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31169081

RESUMO

Ciprofloxacin resistance in Salmonella has been increasingly reported due to the emergence and dissemination of multiple Plasmid-Mediated Quinolone Resistance (PMQR) determinants, which are mainly located in non-conjugative plasmids or chromosome. In this study, we aimed to depict the molecular mechanisms underlying the rare phenomenon of horizontal transfer of ciprofloxacin resistance phenotype in Salmonella by conjugation experiments, S1-PFGE and complete plasmid sequencing. Two types of non-conjugative plasmids, namely an IncX1 type carrying a qnrS1 gene, and an IncH1 plasmid carrying the oqxAB-qnrS gene, both ciprofloxacin resistance determinants in Salmonella, were recovered from two Salmonella strains. Importantly, these non-conjugative plasmids could be fused with a novel Incl1 type conjugative helper plasmid, which could target insertion sequence (IS) elements located in the non-conjugative, ciprofloxacin-resistance-encoding plasmid through replicative transcription, eventually forming a hybrid conjugative plasmid transmissible among members of Enterobacteriaceae. Since our data showed that such conjugative helper plasmids are commonly detectable among clinical Salmonella strains, particularly S. Typhimurium, fusion events leading to generation and enhanced dissemination of conjugative ciprofloxacin resistance-encoding plasmids in Salmonella are expected to result in a sharp increase in the incidence of resistance to fluoroquinolone, the key choice for treating life-threatening Salmonella infections, thereby posing a serious public health threat.


Assuntos
Antibacterianos/farmacologia , Ciprofloxacino/farmacologia , Conjugação Genética , Farmacorresistência Bacteriana , Plasmídeos/genética , Salmonella/efeitos dos fármacos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Enterobacteriaceae/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Plasmídeos/metabolismo , Salmonella/genética , Salmonella/metabolismo , Infecções por Salmonella/microbiologia
13.
BMC Vet Res ; 15(1): 212, 2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31234834

RESUMO

BACKGROUND: Multi-drug resistant bacteria are seen increasingly and there are gaps in our understanding of the complexity of antimicrobial resistance, partially due to a lack of appropriate statistical tools. This hampers efficient treatment, precludes determining appropriate intervention points and renders prevention very difficult. METHODS: We re-analysed data from a previous study using additive Bayesian networks. The data contained information on resistances against seven antimicrobials and seven potential risk factors from 86 non-typhoidal Salmonella isolates from laying hens in 46 farms in Uganda. RESULTS: The final graph contained 22 links between risk factors and antimicrobial resistances. Solely ampicillin resistance was linked to the vaccinating person and disposal of dead birds. Systematic associations between ampicillin and sulfamethoxazole/trimethoprim and chloramphenicol, which was also linked to sulfamethoxazole/trimethoprim were detected. Sulfamethoxazole/trimethoprim was also directly linked to ciprofloxacin and trimethoprim. Trimethoprim was linked to sulfonamide and ciprofloxacin, which was also linked to sulfonamide. Tetracycline was solely linked to ciprofloxacin. CONCLUSIONS: Although the results needs to be interpreted with caution due to a small data set, additive Bayesian network analysis allowed a description of a number of associations between the risk factors and antimicrobial resistances investigated.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Salmonella/efeitos dos fármacos , Animais , Teorema de Bayes , Feminino , Fatores de Risco , Salmonella/classificação , Salmonella/isolamento & purificação , Uganda
14.
Vet Res ; 50(1): 45, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31215485

RESUMO

Field studies on Salmonella infection in suckling piglets are scarce due to the intrinsic difficulties of collecting proper samples (i.e. tonsils or mesenteric lymph nodes), and most of them rely on the analysis of rectal swabs that limit their accuracy. We used 495 slaughtered 4-weeks-old male piglets intended for human consumption from 5 Salmonella-seropositive breeding farms to collect gastrointestinal packages and perform a thorough detection of Salmonella on mesenteric lymph nodes and intestinal content. The overall prevalence of both infection and shedding was high (≈ 36%) indicating that piglets played an active role in Salmonella maintenance in the farms. Major serotypes found in piglets included 4,[5],12:i: (35.4%), Rissen (17.1%), Derby (10.9%) and Bovismorbificans (10.3%). In most of the infected animals (72.8%) the same serotype was found in mesenteric lymph nodes and feces. Significant higher ELISA OD% values were found in meat juice samples from non-infected piglets compared to infected ones (median OD% of 12.0 and 17.3, respectively; P = 0.002) suggesting some protective effect of sow's colostrum. Salmonella was also isolated from feces from weaned sows contemporary of the slaughtered piglets, and 89% of the serotypes identified in sows were also detected in piglets. Pulsed field gel electrophoresis analyses showed that 75% of the piglet isolates that were compared to those of sows were related to them, suggesting the circulation of Salmonella strains between sows and piglets. It appears that improving piglet colostrum intake along with the reduction of the shedding in sows may favor the control of Salmonella infection in breeding farms.


Assuntos
Derrame de Bactérias , Salmonelose Animal/epidemiologia , Salmonella/fisiologia , Doenças dos Suínos/epidemiologia , Desmame , Animais , Intestinos/microbiologia , Linfonodos/microbiologia , Masculino , Prevalência , Salmonelose Animal/prevenção & controle , Salmonelose Animal/transmissão , Estudos Soroepidemiológicos , Espanha/epidemiologia , Sus scrofa , Suínos , Doenças dos Suínos/prevenção & controle , Doenças dos Suínos/transmissão
15.
J Appl Microbiol ; 127(3): 701-712, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31216601

RESUMO

AIMS: Metal nanoparticles are promising materials for the management of infectious diseases as known to have various antimicrobial activities in pathogenic micro-organisms. Among them, gold nanoparticles (AuNPs) are used in a wide range of fields such as photodynamic therapy, molecular diagnostics and drug delivery because of their unique physicochemical properties. However, little is known about the synergistic antibacterial activity and mechanism of AuNPs on pathogenic bacteria. METHODS AND RESULTS: Combinations of AuNPs and cefotaxime and ciprofloxacin showed synergistic interaction against all Salmonella species, however the combination with kanamycin exhibited no interaction. We determined that AuNPs and in combinations with antibiotics exert its antibacterial effect through bacterial apoptosis-like death. AuNPs caused collapse of intracellular divalent cation homeostasis, and conventional antibiotics caused accumulation of reactive oxygen species, which induced apoptotic hallmarks such as membrane depolarization, caspase-like protein activation, cell filamentation and phosphatidylserine externalization. CONCLUSIONS: The cation homeostasis disruption by AuNPs and the accumulation of reactive oxygen species by conventional antibiotics synergistically affected bacterial cell death and induced apoptosis-like death in Salmonella cells. SIGNIFICANCE AND IMPACT OF THE STUDY: The synergistic activity between AuNPs and antibiotics propose that the AuNPs are a potential antibacterial agent and adjuvant for antimicrobial chemotherapy.


Assuntos
Antibacterianos/farmacologia , Ouro/farmacologia , Nanopartículas Metálicas , Apoptose/efeitos dos fármacos , Cefotaxima/farmacologia , Ciprofloxacino/farmacologia , Sinergismo Farmacológico , Espécies Reativas de Oxigênio/metabolismo , Salmonella/efeitos dos fármacos , Salmonella/metabolismo
16.
Talanta ; 201: 126-133, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122402

RESUMO

Upconversion nanoparticle-based lateral flow assays (UCNP-LFAs) have attracted significant attention in point-of-care testing (POCT) applications, due to the long-term photostability and enhanced signal-to-background noise ratio. The existing UCNP-LFAs generally require peripheral equipment for exciting fluorescent signals and reading out fluorescence results, which are generally bulky and expensive. Herein, we developed a miniaturized and portable UCNP-LFA platform, which is composed of a LFA detection system, an UCNP-LFA reader and a smartphone-assisted UCNP-LFA analyzer. The LFA detection system is based on three types of UCNPs for multiplexed detection. The reader has a dimension of 24.0 cm × 9.4 cm × 5.4 cm (L × W × H) and weight of 0.9 kg. The analyzer based on the custom-designed software of a smartphone (termed as UCNP-LFA analyzer) can get the quantitative analysis results in a real-time manner. We demonstrated the universality of this platform by highly sensitive and quantitative detections of several kinds of targets, including small molecule (ochratoxin A, OTA), heavy metal ion (Hg2+), bacteria (salmonella, SE), nucleic acid (hepatitis B virus, HBV) and protein (growth stimulation expressed gene 2, ST-2). Our developed UCNP-LFA platform holds great promise for applications in disease diagnostics, environmental pollution monitoring and food safety at the point of care.


Assuntos
Imunoensaio/métodos , Nanopartículas/química , Testes Imediatos , Anticorpos/química , Biomarcadores/sangue , DNA/análise , DNA/química , DNA/genética , Érbio/química , Fluoretos/química , Fluoretos/efeitos da radiação , Vírus da Hepatite B/genética , Humanos , Imunoensaio/instrumentação , Proteína 1 Semelhante a Receptor de Interleucina-1/sangue , Proteína 1 Semelhante a Receptor de Interleucina-1/imunologia , Limite de Detecção , Mercúrio/análise , Nanopartículas/efeitos da radiação , Hibridização de Ácido Nucleico , Salmonella/isolamento & purificação , Smartphone , Espectrometria de Fluorescência/métodos , Itérbio/química , Ítrio/química , Ítrio/efeitos da radiação
17.
Prev Vet Med ; 168: 39-51, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31097122

RESUMO

A national baseline study was conducted between December 2012 and December 2013 to determine the pre-packaging prevalence and concentration of foodborne pathogens on broiler chicken carcasses and parts at processing; a survey was implemented simultaneously to collect data on the processing practices used to control these pathogens. Thirty federally-registered Canadian poultry processing establishments completed the questionnaire. A total of 2,732 samples of carcasses and parts (breast and thigh pieces) were collected over the study period from these establishments. For Salmonella, the overall proportion positive was 0.22 (95% CI 0.20, 0.23), and the mean concentration was 0.67 (95% CI 0.51, 0.83) MPN/mL of rinse fluid. Multivariable regression models with random intercepts for the establishment and the date of sampling were used to identify associations between Salmonella prevalence and concentration and processing practices. In the final logistic regression model for the prevalence outcome (positive or negative sample), there were three statistically significant variables: product type (carcass or part); chilling method (water or air); and chlorine use in the establishment (chlorine, cetylpyridinium chloride, or neither). The likelihood of testing positive for Salmonella was higher on parts than carcasses (OR 3.03, 95% CI 2.38, 3.86), and higher when cetylpyridinium chloride was used (OR 2.00, 95% CI 1.36, 2.95), or when other processing aids were used (OR 1.99, 95% CI 1.26, 3.15), than when chlorine was used. Water chilling was negatively associated with testing positive for Salmonella when compared with air chilling (OR 0.68, 95% CI 0.48, 0.96). In the final linear regression model for the concentration outcome (log10 MPN/mL), there was one statistically significant variable chilling method, where water chilling was associated with a decrease in concentration (ß -0.23, 95% CI -0.38, -0.08 log10 MPN/mL). The intraclass correlation coefficients for establishment and date sampling were 0.02 and 0.23 in the linear regression model, and 0.01 and 0.34 in the logistic regression model, respectively. Further studies to explore the methods to reduce microbial contamination during the air chilling and cut-up and boning processes in broiler chicken establishments in Canada are recommended.


Assuntos
Galinhas , Manipulação de Alimentos , Doenças das Aves Domésticas/epidemiologia , Produtos Avícolas/microbiologia , Salmonelose Animal/epidemiologia , Matadouros , Animais , Canadá/epidemiologia , Indústria de Embalagem de Carne , Doenças das Aves Domésticas/microbiologia , Prevalência , Salmonella , Salmonelose Animal/etiologia
19.
J Food Sci ; 84(6): 1494-1500, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31059142

RESUMO

Strawberry is a healthy fruit with numerous health-benefit compounds. Unfortunately, it is highly perishable and occasionally can be contaminated with foodborne pathogens. The overall goal of this study is to evaluate pulsed light (PL) processing for disinfection of strawberries, extension of shelf life, and preservation of quality attributes and compounds that are beneficial to health. Preliminary screening of PL conditions based on visual appearance of strawberries was conducted, and 3 PL treatments were identified for full evaluation. Salmonella inoculum was artificially deposited onto the skin of strawberries via spot-inoculation or dip-inoculation. The 3 PL treatments slightly reduced the level of inoculated Salmonella on strawberries, ranging from approximately 0.4 to 0.8 log reduction. They also slowed down the visible mold development on strawberries by 2 to 4 days compared with the untreated control. Regarding the natural yeasts and molds, the quality attributes (weight loss and firmness), and the bioactive compounds (total anthocyanin, total phenolics, and total antioxidant activity). The 3 PL treatment showed no significant or negligible difference comparing to the control group. Overall, the 3 PL treatments demonstrated potential in extending the shelf life of strawberries. The quality attributes or the bioactive compounds of strawberries showed no significant or minimal change after these PL treatments. PRACTICAL APPLICATION: Pulsed light (PL) processing for strawberry decontamination and shelf life extension was evaluated. Results demonstrated that PL processing could have the potency to improve strawberry shelf life without significantly affecting the quality and bioactive compounds of strawberries.


Assuntos
Qualidade dos Alimentos , Inocuidade dos Alimentos/métodos , Armazenamento de Alimentos/métodos , Fragaria , Frutas/microbiologia , Luz , Antocianinas/análise , Antioxidantes/análise , Descontaminação/métodos , Microbiologia de Alimentos/métodos , Frutas/química , Fungos/crescimento & desenvolvimento , Fenóis/análise , Salmonella/crescimento & desenvolvimento
20.
Food Chem ; 294: 468-476, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126489

RESUMO

Detection of pathogenic bacteria by polymerase chain reaction (PCR) is progressively emerging, although it is still hindered by a complex matrix, long-term bacterial enrichment and low bacterial abundance. Here, we report a novel material based on boronate affinity for recognition and enrichment of bacteria using a pre-PCR method. After optimization, the material exhibited high boronate affinity toward bacteria, with adsorption capacities of S. aureus and Salmonella spp. incubated in 0.01 M PBS (pH 7.4) at 37 °C for 15 min calculated as (906.60 ±â€¯15.73) × 107 cfu/g and (582.59 ±â€¯13.19) × 107 cfu/g, respectively, without any bacterial death during the binding process. The material was then applied to enrich S. aureus and Salmonella spp. from the spiked water and 25% cow milk samples followed by mPCR, which resulted in high bacterial enrichment and demonstrated great potential for selective enrichment of bacteria in food samples.


Assuntos
Compostos de Boro/química , Microbiologia de Alimentos/métodos , Salmonella/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Adsorção , Animais , Compostos de Boro/síntese química , Bovinos , Água Potável/microbiologia , Doenças Transmitidas por Alimentos/microbiologia , Concentração de Íons de Hidrogênio , Leite/microbiologia , Polietilenoimina/química , Reação em Cadeia da Polimerase , Salmonella/genética , Sensibilidade e Especificidade , Sefarose/química , Staphylococcus aureus/genética
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