Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21.158
Filtrar
1.
Vet Rec ; 190(9): 355, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35521841
2.
Microb Genom ; 8(5)2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35511231

RESUMO

Non-typhoidal Salmonella (NTS) is a major cause of bacterial enterocolitis globally but also causes invasive bloodstream infections. Antimicrobial resistance (AMR) hampers the treatment of these infections and understanding how AMR spreads between NTS may help in developing effective strategies. We investigated NTS isolates associated with invasive disease, diarrhoeal disease and asymptomatic carriage in animals and humans from Vietnam. Isolates included multiple serovars and both common and rare phenotypic AMR profiles; long- and short-read sequencing was used to investigate the genetic mechanisms and genomic backgrounds associated with phenotypic AMR profiles. We demonstrate concordance between most AMR genotypes and phenotypes but identified large genotypic diversity in clinically relevant phenotypes and the high mobility potential of AMR genes (ARGs) in this setting. We found that 84 % of ARGs identified were located on plasmids, most commonly those containing IncHI1A_1 and IncHI1B(R27)_1_R27 replicons (33%), and those containing IncHI2_1 and IncHI2A_1 replicons (31%). The vast majority (95%) of ARGS were found within 10 kbp of IS6/IS26 elements, which provide plasmids with a mechanism to exchange ARGs between plasmids and other parts of the genome. Whole genome sequencing with targeted long-read sequencing applied in a One Health context identified a comparatively limited number of insertion sequences and plasmid replicons associated with AMR. Therefore, in the context of NTS from Vietnam and likely for other settings as well, the mechanisms by which ARGs move contribute to a more successful AMR profile than the specific ARGs, facilitating the adaptation of bacteria to different environments or selection pressures.


Assuntos
Antibacterianos , Febre Tifoide , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Humanos , Salmonella , Sorogrupo , Vietnã
3.
PLoS One ; 17(5): e0267510, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35511793

RESUMO

The early detection of infectious disease outbreaks is a crucial task to protect population health. To this end, public health surveillance systems have been established to systematically collect and analyse infectious disease data. A variety of statistical tools are available, which detect potential outbreaks as abberations from an expected endemic level using these data. Here, we present supervised hidden Markov models for disease outbreak detection, which use reported outbreaks that are routinely collected in the German infectious disease surveillance system and have not been leveraged so far. This allows to directly integrate labeled outbreak data in a statistical time series model for outbreak detection. We evaluate our model using real Salmonella and Campylobacter data, as well as simulations. The proposed supervised learning approach performs substantially better than unsupervised learning and on par with or better than a state-of-the-art approach, which is applied in multiple European countries including Germany.


Assuntos
Infecções por Campylobacter , Doenças Transmissíveis , Infecções por Campylobacter/diagnóstico , Infecções por Campylobacter/epidemiologia , Doenças Transmissíveis/epidemiologia , Surtos de Doenças , Alemanha/epidemiologia , Humanos , Vigilância da População , Vigilância em Saúde Pública , Salmonella , Aprendizado de Máquina Supervisionado
4.
Open Vet J ; 12(2): 303-307, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35603068

RESUMO

Background: In Italy, an autogenous registered vaccine, adjuvanted with aluminum hydroxide, can be administrated to contrast Salmonella enterica subsp. enterica serovar abortus equi infection, coupled to a specific antimicrobial treatment. Case Description: Here, we report the case of an abortion outbreak by Salmonella abortus equi in Central Italy where mares were vaccinated but immediately developed a strong local reaction, maybe due to the adjuvant. Promptly, another autogenous vaccine, substituting the aluminum hydroxide with a new generation adjuvant (Montanide™ Seppic IMS1313), was produced and administrated. The new formulated vaccine did not cause any adverse outcome and conferred high protection titers against the infection. To the best of our knowledge, this is the first reported case of immunization by a vaccine adjuvanted with Montanide™ Seppic IMS1313 in horses. Conclusion: This approach may be used as a preventive strategy for further outbreaks in association with the application of recommended biosafety principles.


Assuntos
Autovacinas , Salmonella enterica , Adjuvantes Imunológicos , Adjuvantes Farmacêuticos , Hidróxido de Alumínio , Animais , Surtos de Doenças/prevenção & controle , Surtos de Doenças/veterinária , Feminino , Cavalos , Gravidez , Salmonella , Sorogrupo
5.
PLoS One ; 17(4): e0258435, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35421088

RESUMO

The aim of the present study was to assess the microbial quality of five ready-to-eat food such as bread, pasta, rice with sauce, beans and milk sold in five localities of Burkina Faso namely, Ouagadougou, Bobo-Dioulasso, Dakola, Cinkansé and Niangoloko. One hundred and one samples were collected and microbial quality were assessed by evaluating the food hygiene indicators such as total aerobic mesophilic flora, total coliforms, thermotolerant coliforms, yeast and mould. Food safety indicators such as Escherichia coli, Salmonella, coagulase-positive staphylococci, Clostridium perfringens and Bacillus cereus were also tested for contamination. Samples were tested according to ISO guidelines for all parameters. The results showed that 74 (73.27%) of samples were satisfactory while 15 (14.85%) were acceptable and 12 (11.88%) were not satisfactory according to international standards. Among the food safety indicators sought, Escherichia coli was detected in two samples and Bacillus cereus in four samples. Most of the analyzed food exhibited good hygiene behavior within the acceptable limits and the highest of not satisfactory rate was observed in milk powder and rice with sauce. Ouagadougou samples recorded the highest number of not satisfactory samples. Despite the general quality was satisfactory, the presence of specific microorganisms such as coliforms is indicative of the poor hygiene surrounded these foods. It is therefore necessary to train and follow up the vendors in the handling of equipment, hand-washing practices and selling environment hygiene for better improvement of the quality of the street foods.


Assuntos
Microbiologia de Alimentos , Salmonella , Animais , Bacillus cereus , Burkina Faso , Contagem de Colônia Microbiana , Escherichia coli , Contaminação de Alimentos/análise , Manipulação de Alimentos , Leite
6.
BMC Microbiol ; 22(1): 84, 2022 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-35361106

RESUMO

BACKGROUND: Salmonella is one of the foodborne pathogens affecting public health around the globe. A cross-sectional bacteriological study was conducted from December 2019 to November 2020. This study aimed to isolate, molecularly detect and determine antibiotic susceptibility patterns of Salmonella from raw cows' milk collected from dairy farms and households in Hawassa, Arsi Negele, and Dale districts. MATERIALS AND METHODS: A total of 384 raw milk samples were collected using a simple random sampling technique. Standard bacteriological and biochemical tests were used to isolate Salmonella. The positive samples were further confirmed by the molecular test. Kirby-Bauer disk diffusion method was used for antimicrobial susceptibility testing of Salmonella. RESULTS: Using bacteriological and biochemical detection tests, Salmonella was isolated from 10.42% (N = 40) of the total sample. However, in molecular detection, only 32 of the 40 isolates were confirmed to be Salmonella using PCR test. The prevalence was 8.54, 12.69, and 10.46% in Hawassa, Dale, and Arsi Negele districts, respectively. Bacteriological prevalence did not vary significantly between the districts (P > 0.05). Likewise, no significant (P > 0.05) variation was observed in the Salmonella isolation rate between households (12.5%) and farms (8.33%) as well as between dry (8.85%) and wet (11.98%) seasons. Based on herd size, the isolation rate of Salmonella was significantly higher (P < 0.05) in large-scale farms (19.51%) than in small (5.1%) or medium (5.6%) scale dairy farms. The result of the antibiotic susceptibility test showed that Salmonella isolates were 100% resistant to ampicillin, while they were 100% sensitive to ciprofloxacin. Multi-drug resistance (MDR) was demonstrated in all isolates. CONCLUSION: This study showed that Salmonella is widespread in the raw milk samples and developing MDR, which may be of public health concern in the study area. It is therefore important that dairy farmers and raw milk sellers in the study area take serious measures to avoid contamination of the milk with Salmonella spp. In addition, the active commitment of the animal health departments in the respective districts to sensitizing dairy farmers and the sensible use of antibiotics at the farm level can help to reduce the antibiotic resistance of Salmonella spp.


Assuntos
Leite , Salmonella , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bovinos , Estudos Transversais , Etiópia/epidemiologia , Fazendas , Feminino , Salmonella/genética
7.
Foodborne Pathog Dis ; 19(5): 341-348, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35404147

RESUMO

Weather can impact infectious disease transmission, particularly for heat-sensitive pathogens, such as Salmonella. We conducted an ecological time-series analysis to estimate short-term associations between nonoutbreak-related notifications of Salmonella and weather conditions-temperature and rainfall-in Melbourne, Australia from 2000 to 2019. Distributed lag nonlinear models were created to analyze weather-salmonellosis associations and potential lag times on a weekly time scale, controlling for seasonality and long-term trends. Warmer temperatures were associated with increased risk of notification. Effects were temporally lagged, with the highest associations observed for warm temperatures 2-6 (greatest at 4) weeks before notification. The overall estimated relative risk of salmonellosis increased twofold at 33°C compared to the average weekly temperature (20.35°C) for the 8-week period preceding the disease notification. For Salmonella Typhimurium alone, this occurred at temperatures over 32°C. There were no statistically significant associations with rainfall and notification rates in any of the analyses performed. This study demonstrates the short-term influences of warm temperatures on Salmonella infections in Melbourne over a 20-year period. Salmonelloses are already the second most notified gastrointestinal diseases in Victoria, and these findings suggest that notifications may increase with increasing temperatures. This evidence contributes to previous findings that indicate concerns for public health with continued warm weather.


Assuntos
Intoxicação Alimentar por Salmonella , Infecções por Salmonella , Austrália/epidemiologia , Humanos , Salmonella , Intoxicação Alimentar por Salmonella/epidemiologia , Infecções por Salmonella/epidemiologia , Estações do Ano , Temperatura , Tempo (Meteorologia)
8.
Int J Infect Dis ; 120: 210-216, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35472528

RESUMO

OBJECTIVES: To evaluate a duplex droplet digital polymerase chain reaction (ddPCR) assay targeting Salmonella fimY and Shigella ipaH genes. METHODS: The linear range, precision, analytical sensitivity, and analytical specificity of the ddPCR assay were analyzed. The ddPCR assay was compared with quantitative real-time PCR (qPCR) using 362 stool samples from 187 children with mild diarrhea and 175 children without diarrhea. RESULTS: The duplex ddPCR assay showed good linearity in the range of 5.3 × 100 to 1.24 × 105 copies/reaction for Salmonella and 1.9 × 100 to 1.84 × 105 copies/reaction for Shigella. When analyzed with spiked stool samples, the limit of detection and limit of quantification were 550 and 5500 colony-forming units per mL of stool sample for Shigella, respectively, whereas both were 1.0 × 104 colony-forming units per mL of stool sample for Salmonella. Among 362 stool samples, more samples were detected as positive by ddPCR than by qPCR. Salmonella load was significantly higher in diarrheal samples than in non-diarrheal samples. Determined by receiver-operating characteristic analysis, the optimal cut-off value was 1.25 × 104 copies/mL of stool sample to distinguish between symptomatic and asymptomatic Salmonella infections. CONCLUSION: Salmonella and Shigella prevalence may have been underestimated in the past.


Assuntos
Shigella , Criança , Diarreia/diagnóstico , Humanos , Reação em Cadeia da Polimerase em Tempo Real , Salmonella/genética , Sensibilidade e Especificidade , Shigella/genética
9.
Nucleic Acids Res ; 50(9): 5158-5170, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35489061

RESUMO

Pseudogenes (genes disrupted by frameshift or in-frame stop codons) are ubiquitously present in the bacterial genome and considered as nonfunctional fossil. Here, we used RNA-seq and mass-spectrometry technologies to measure the transcriptomes and proteomes of Salmonella enterica serovars Paratyphi A and Typhi. All pseudogenes' mRNA sequences remained disrupted, and were present at comparable levels to their intact homologs. At the protein level, however, 101 out of 161 pseudogenes suggested successful translation, with their low expression regardless of growth conditions, genetic background and pseudogenization causes. The majority of frameshifting detected was compensatory for -1 frameshift mutations. Readthrough of in-frame stop codons primarily involved UAG; and cytosine was the most frequent base adjacent to the codon. Using a fluorescence reporter system, fifteen pseudogenes were confirmed to express successfully in vivo in Escherichia coli. Expression of the intact copy of the fifteen pseudogenes in S. Typhi affected bacterial pathogenesis as revealed in human macrophage and epithelial cell infection models. The above findings suggest the need to revisit the nonstandard translation mechanism as well as the biological role of pseudogenes in the bacterial genome.


Assuntos
Proteogenômica , Salmonella enterica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Códon de Terminação/metabolismo , Genoma Bacteriano/genética , Humanos , Pseudogenes/genética , Salmonella/genética , Salmonella enterica/genética , Salmonella enterica/metabolismo , Salmonella typhi/genética , Salmonella typhi/metabolismo
10.
Appl Environ Microbiol ; 88(8): e0020422, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35384708

RESUMO

Poultry remains a considerable source of foodborne salmonellosis despite significant reduction of Salmonella incidence during processing. There are multiple entry points for Salmonella during production that can lead to contamination during slaughter, and it is important to distinguish the serovars present between the different stages to enact appropriate controls. National Salmonella data from the U.S. Department of Agriculture-Food Safety Inspection Service (USDA-FSIS) monitoring of poultry processing was analyzed from 2016 to 2020. The overall Salmonella incidence at processing in broiler carcasses and intact parts (parts) decreased from 9.00 to 6.57% over this period. The incidence in parts was higher (11.15%) than in carcasses (4.78%). Regional differences include higher proportions of serovars Infantis and Typhimurium in the Atlantic and higher proportion of serovar Schwarzengrund in the Southeast. For Georgia, the largest broiler-producing state, USDA-FSIS data were compared to Salmonella monitoring data from breeder flocks over the same period, revealing serovar Kentucky as the major serovar in breeders (67.91%) during production but not at processing, suggesting that it is more effectively removed during antimicrobial interventions. CRISPR-SeroSeq was performed on breeder samples collected between 2020 and 2021 to explain the incongruence between pre- and postharvest and showed that 32% of samples contain multiple serovars, with up to 11 serovars found in a single flock. High-resolution sequencing identifies serovar patterns at the population level and can provide insight to develop targeted controls. The work presented may apply to other food production systems where Salmonella is a concern, since it overcomes limitations associated with conventional culture. IMPORTANCE Salmonella is a leading cause of bacterial foodborne illness in the United States, with poultry as a significant Salmonella reservoir. We show the relative decrease in Salmonella over a 5-year period from 2016 to 2020 in processed chicken parts and highlight regional differences with respect to the prevalence of clinically important Salmonella serovars. Our results show that the discrepancy between Salmonella serovars found in pre- and postharvest poultry during surveillance are due in part by the limited detection depth offered by traditional culture techniques. Despite the reduction of Salmonella at processing, the number of human salmonellosis cases has remained stable, which may be attributed to differences in virulence among serovars and their associated risk. When monitoring for Salmonella, it is imperative to identify all serovars present to appropriately assess public health risk and to implement the most effective Salmonella controls.


Assuntos
Doenças das Aves Domésticas , Intoxicação Alimentar por Salmonella , Infecções por Salmonella , Animais , Galinhas/microbiologia , Humanos , Aves Domésticas/microbiologia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Salmonella/genética , Estados Unidos/epidemiologia
11.
J Med Microbiol ; 71(4)2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35476604

RESUMO

Introduction. The conventional adjuvants used in vaccines have limitations like induction of an imbalanced Th1 and Th2 immune response. To overcome this limitation, novel adjuvants and newer forms of existing adjuvants like calcium phosphate nanoparticles are being tested.Hypothesis/Gap Statement. Calcium phosphate adjuvanted outer membrane proteins vaccine may work as an efficient, safe and cost effective vaccine against Salmonella Typhi.Aim. Our goals were to evaluate the potential of calcium phosphate nanoparticles as an adjuvant using outer membrane proteins (Omps) of Salmonella Typhi as antigens for immune response, with montanide (commercially available adjuvant) as control, and its toxicity in rats.Methodology. Calcium phosphate adjuvanted outer membrane proteins nanoparticles were synthesized and characterized. The efficacy of vaccine formulation in mice and toxicity assay were carried out in rats.Results. The calcium phosphate nanoparticles varying in size between 20-50 nm had entrapment efficiency of 41.5% and loading capacity of 54%. The calcium phosphate nanoparticle-Omps vaccine formulation (nanoparticle-Omps) induced a strong humoral immune response, which was significantly higher than the control group for the entire period of study. In the montanide-Omps group the initial very high immune response declined steeply and then remained steady. The immune response induced by nanoparticle-Omps did not change appreciably. The cell mediated immune response as measured by lymphocyte proliferation assay and delayed type hypersensitivity test showed a higher response (P<0.01) for the nanoparticles-Omps group as compared to montanide-Omps group. The bacterial clearance assay also showed higher clearance in the nanoparticles-Omps group as compared to montanide-Omps group (approx 1.4%). The toxicity analysis in rats showed no difference in the values of toxicity biomarkers and blood chemistry parameters, revealing vaccine formulation was non-toxic in rats.Conclusion. Calcium phosphate nanoparticles as adjuvant in vaccines is safe, have good encapsulation and loading capacity and induce a strong cell mediated, humoral and protective immune response.


Assuntos
Nanopartículas , Febre Tifoide , Adjuvantes Imunológicos , Animais , Fosfatos de Cálcio/química , Proteínas de Membrana , Camundongos , Óleo Mineral , Nanopartículas/química , Ratos , Salmonella , Salmonella typhi , Febre Tifoide/prevenção & controle
12.
Int J Food Microbiol ; 370: 109638, 2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35378381

RESUMO

Thermal inactivation of pathogenic and spoilage organisms in low and intermediate moisture foods is of critical importance for guaranteeing microbiological safety and stability of these products. Producers tendentially reduce salt in low and intermediate moisture foods because of nutritional health considerations, but it is unclear how this affects microbial inactivation rates during pasteurization. In this study we predict the time to achieve a pre-defined 6-log reduction for Salmonella enterica subsp. enterica serovar Napoli (hereafter: S. Napoli) and Eurotium herbariorum mould spores (hereafter: E. herbariorum spores) and the relationship with product characteristics. We tested 31 design products for heat inactivation of S. Napoli and 29 design products for heat inactivation of E. herbariorum spores. We used a global Bayesian regression combining primary Weibull models with a secondary regression model to relate pasteurization temperature and product characteristics (water activity (aw), pH, and fractions of sodium chloride, sucrose and oil on product) to microbial counts. With this model, we predict the time to 6-log reduction. Thermal inactivation rates were much higher for vegetative S. Napoli than for E. herbariorum spores. Also, inactivation curves were non-linear for many experiments. There were significant associations between the Weibull model parameters and temperature, and pH and aw for S. Napoli and E. herbariorum spores, respectively. We parameterized an inactivation model for S. Napoli and E. herbariorum spores using design products with a broad range of characteristics and showed how the simplified approach of using D-values does not accurately describe the non-linearity of thermal inactivation for both types of organism. Results of our model can be used to produce accurate heat inactivation predictions as input for the pasteurization process in factories where intermediate moisture foods are manufactured.


Assuntos
Microbiologia de Alimentos , Temperatura Alta , Aspergillus , Teorema de Bayes , Contagem de Colônia Microbiana , Salmonella/fisiologia , Esporos Fúngicos
13.
Int J Food Microbiol ; 370: 109668, 2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35410797

RESUMO

Sprout consumption has become more popular due to a new variety of sprouts being introduced to the market. However, sprout seeds are a major source of sprout contamination and have been linked to most sprout-associated foodborne outbreaks. This study investigated Salmonella reduction in sunflower and roselle seeds using various sanitizing agents including water, water at 55 °C, sodium hypochlorite (NaOCl), diluted vinegar, acidic electrolyzed water (ACEW), and alkaline electrolyzed water (ALEW). Diluted vinegar containing 1.25% (v/v) acetic acid was the most effective treatment to inactivate Salmonella in sunflower seeds, resulting in a 3.82 log reduction after 15-min treatment. High concentrations of NaOCl (available chlorine concentration (ACC) 1692 mg/L) and ACEW (pH 2.76, oxidation-reduction potential 1093 mV, ACC 48 mg/L) had significantly lower antimicrobial activity with 3.20 and 2.39 log reduction, respectively, after 15-min treatment. Disinfecting roselle seeds for 15 min with water at 55 °C and diluted vinegar had comparable efficacy to reduce Salmonella by 2.54 and 2.48 log, respectively. There were no significant changes in Salmonella reduction among the high and low concentrations of NaOCl containing ACC 79 and 1692 mg/L, respectively, and ACEW in roselle seeds during 5-15 min of exposure time. All tested treatment solutions had no negative impact on the percentage of seed germination with over 96% and 92.56-95.89% for sunflower and roselle seeds, respectively. Conversely, the fresh weight and length of sunflower and roselle sprouts were influenced significantly by the types of sanitizing agents used for decontaminating the seeds. Collectively, our findings may contribute to the development of effective seed sanitization measure for sunflower and roselle seeds to reduce the risk of Salmonella-associated outbreaks linked to sprout consumption.


Assuntos
Helianthus , Hibiscus , Ácido Acético/farmacologia , Cloro/farmacologia , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Germinação , Medicago sativa , Salmonella , Sementes , Água/farmacologia
14.
Microb Genom ; 8(4)2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35451954

RESUMO

Although Salmonella Derby ST71 strains have been recognized as poultry-specific by previous studies, multiple swine-associated S. Derby ST71 strains were identified in this long-term, multi-site epidemic study. Here, 15 representative swine-associated S. Derby ST71 strains were sequenced and compared with 65 (one swine-associated and 64 poultry-associated) S. Derby ST71 strains available in the NCBI database at a pangenomic level through comparative genomics analysis to identify genomic features related to the differentiation of swine-associated strains and previously reported poultry-associated strains. The distribution patterns of known Salmonella pathogenicity islands (SPIs) and virulence factor (VF) encoding genes were not capable of differentiating between the two strain groups. The results demonstrated that the S. Derby ST71 population harbours an open pan-genome, and swine-associated ST71 strains contain many more genes than the poultry-associated strains, mainly attributed to the prophage sequence contents in the genomes. The numbers of prophage sequences identified in the swine-associated strains were higher than those in the poultry-associated strains. Prophages specifically harboured by the swine-associated strains were found to contain genes that facilitate niche adaptation for the bacterial hosts. Gene deletion experiments revealed that the dam gene specifically present in the prophage of the swine-associated strains is important for S. Derby to adhere onto the host cells. This study provides novel insights into the roles of prophages during the genome differentiation of Salmonella.


Assuntos
Genoma Bacteriano , Prófagos , Animais , Genoma Bacteriano/genética , Niacinamida/análogos & derivados , Aves Domésticas/genética , Prófagos/genética , Salmonella/genética , Suínos
15.
Biomed Res Int ; 2022: 9977371, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35402608

RESUMO

The release of untreated wastes from abattoirs into the environment and nearby water bodies poses a significant threat to public health. Such litters may contain pathogens, including antibiotic-resistant bacteria. This study investigated 80 samples collected from butchering tables, slaughter slabs, meat rinsing points, and abattoir wastes receiving water from two abattoirs (A and B). Total Enterobacteriaceae count (TEC) for each sample was determined, and Escherichia coli (E. coli), Salmonella spp., Shigella spp., and Staphylococcus aureus (S. aureus) were isolated and identified. Antimicrobial susceptibility testing was done on all bacterial isolates against nine locally used antibiotics. Overall, 118 bacterial isolates, comprising E. coli (42.5%), Salmonella spp. (27.5%), Shigella spp. (37.5%), and S. aureus (40.0%), were recovered. Of the 118 bacterial isolates, 104 (88.1%) were multidrug-resistant, including 58 (55.8%) from abattoir A and 46 (44.2%) from abattoir B; however, this difference was not statistically significant (p = 0.6837). Of the 32 S. aureus isolates, 29 (90.6%) were multidrug-resistant. All S. aureus were 100% sensitive to vancomycin, kanamycin, and amikacin. Similarly, 31 (91.2%) of the 34 E. coli isolates recovered in this study were multidrug-resistant. Salmonella spp. and Shigella spp. also showed high levels of multidrug resistance corresponding to 81.8% and 86.7%, respectively. All isolates of E. coli, Salmonella, and Shigella were 100% resistant to ampicillin and 100% sensitive to ciprofloxacin. Minimum and maximum mean values for TEC were 3.62-5.83 log CFU/mL for abattoir A and 4.08-5.56 log CFU/mL for abattoir B. The highest and lowest TEC counts were from slaughter slab and upstream water, respectively, in each abattoir. Our results indicate a predominance of multidrug-resistant bacteria in abattoir wastes and their receiving waters in the study sites. Hence, we recommend the treatment of abattoir wastes before disposal and improved hygiene and sanitation practices to enhance public health.


Assuntos
Infecções por Escherichia coli , Infecções Estafilocócicas , Matadouros , Antibacterianos/farmacologia , Bactérias , Camarões , Enterobacteriaceae , Escherichia coli , Humanos , Saúde Pública , Salmonella , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus , Água
16.
Anal Chim Acta ; 1205: 339781, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35414391

RESUMO

In this study, a loop-mediated isothermal amplification-based nucleic acid lateral flow assay (LAMP-NALFA) system was developed for the specific and multiplex detection of genetic markers at a low cost. In principle, the LAMP reaction was optimized to generate a single-stranded sequence in the LAMP product, which was designed to serve as a barcode sequence and to specifically bind to the DNA capture on a NALFA strip. As a target genetic marker, the Salmonella enterotoxin (stn) gene was chosen and determined down to 9 aM (∼5.44 copies/µL). Importantly, the proposed system clearly discriminated the specific target amplification products from non-specific amplification products resulting from primers or non-target nucleic acids, proving the high selectivity of the LAMP-NALFA system. Furthermore, the practical applicability of the system was demonstrated by detecting Salmonella bacteria in Luria-Bertani medium, drinking water, and eggshells, with a limit of detection of 1.6 CFU. Finally, two different bacteria (Salmonella and Staphylococcus) were simultaneously determined by the multiplex LAMP-NALFA system. It is expected that the LAMP-NALFA system could be used in a point-of-care setting for the detection of bacteria or viruses, consequently improving both individual and public health.


Assuntos
Técnicas de Amplificação de Ácido Nucleico , Ácidos Nucleicos , Marcadores Genéticos , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Salmonella/genética , Sensibilidade e Especificidade
17.
Environ Monit Assess ; 194(5): 373, 2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35435507

RESUMO

The use of computer-based tools has been becoming popular in the field of produce safety. Various algorithms have been applied to predict the population and presence of indicator microorganisms and pathogens in agricultural water sources. The purpose of this study is to improve the Salmonella prediction success of deep feed-forward neural network (DFNN) in agricultural surface waters with a determined correlation value based on selected features. Datasets were collected from six agricultural ponds in Central Florida. The most successful physicochemical and environmental features were selected by the gain ratio for the prediction of generic Escherichia coli population with machine learning algorithms (decision tree, random forest, support vector machine). Salmonella prediction success of DFNN was evaluated with dataset including selected environmental and physicochemical features combined with predicted E. coli populations with and without correlation value. The performance of correlation value was evaluated with all possible mathematical dataset combinations (nCr) of six ponds. The higher accuracy performances (%) were achieved through DFNN analyses with correlation value between 88.89 and 98.41 compared to values with no correlation value from 83.68 to 96.99 for all dataset combinations. The findings emphasize the success of determined correlation value for the prediction of Salmonella presence in agricultural surface waters.


Assuntos
Monitoramento Ambiental , Escherichia coli , Aprendizado de Máquina , Redes Neurais de Computação , Salmonella
18.
Bull Math Biol ; 84(5): 56, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35380320

RESUMO

Bacteria have developed resistance to antibiotics by various mechanisms, notable amongst these is the use of permeation barriers and the expulsion of antibiotics via efflux pumps. The resistance-nodulation-division (RND) family of efflux pumps is found in Gram-negative bacteria and a major contributor to multidrug resistance (MDR). In particular, Salmonella encodes five RND efflux pump systems: AcrAB, AcrAD, AcrEF, MdsAB and MdtAB which have different substrate ranges including many antibiotics. We produce a spatial partial differential equation (PDE) model governing the diffusion and efflux of antibiotic in Salmonella, via these RND efflux pumps. Using parameter fitting techniques on experimental data, we are able to establish the behaviour of multiple wild-type and efflux mutant Salmonella strains, which enables us to produce efflux profiles for each individual efflux pump system. By combining the model with a gene regulatory network (GRN) model of efflux regulation, we simulate how the bacteria respond to their environment. Finally, performing a parameter sensitivity analysis, we look into various different targets to inhibit the efflux pumps. The model provides an in silico framework with which to test these potential adjuvants to counter MDR.


Assuntos
Farmacorresistência Bacteriana Múltipla , Proteínas de Membrana Transportadoras , Modelos Biológicos , Salmonella , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Membrana Transportadoras/genética , Salmonella/efeitos dos fármacos , Salmonella/genética
19.
BMC Genomics ; 23(1): 268, 2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35387579

RESUMO

BACKGROUND: Of the > 2600 Salmonella serovars, Salmonella enterica serovar I 4,[5],12:i:- (serovar I 4,[5],12:i:-) has emerged as one of the most common causes of human salmonellosis and the most frequent multidrug-resistant (MDR; resistance to ≥3 antimicrobial classes) nontyphoidal Salmonella serovar in the U.S. Serovar I 4,[5],12:i:- isolates have been described globally with resistance to ampicillin, streptomycin, sulfisoxazole, and tetracycline (R-type ASSuT) and an integrative and conjugative element with multi-metal tolerance named Salmonella Genomic Island 4 (SGI-4). RESULTS: We analyzed 13,612 serovar I 4,[5],12:i:- strain sequences available in the NCBI Pathogen Detection database to determine global distribution, animal sources, presence of SGI-4, occurrence of R-type ASSuT, frequency of antimicrobial resistance (AMR), and potential transmission clusters. Genome sequences for serovar I 4,[5],12:i:- strains represented 30 countries from 5 continents (North America, Europe, Asia, Oceania, and South America), but sequences from the United States (59%) and the United Kingdom (28%) were dominant. The metal tolerance island SGI-4 and the R-type ASSuT were present in 71 and 55% of serovar I 4,[5],12:i:- strain sequences, respectively. Sixty-five percent of strain sequences were MDR which correlates to serovar I 4,[5],12:i:- being the most frequent MDR serovar. The distribution of serovar I 4,[5],12:i:- strain sequences in the NCBI Pathogen Detection database suggests that swine-associated strain sequences were the most frequent food-animal source and were significantly more likely to contain the metal tolerance island SGI-4 and genes for MDR compared to all other animal-associated isolate sequences. CONCLUSIONS: Our study illustrates how analysis of genomic sequences from the NCBI Pathogen Detection database can be utilized to identify the prevalence of genetic features such as antimicrobial resistance, metal tolerance, and virulence genes that may be responsible for the successful emergence of bacterial foodborne pathogens.


Assuntos
Salmonella enterica , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Ilhas Genômicas/genética , Testes de Sensibilidade Microbiana , Salmonella/genética , Sorogrupo , Suínos , Estados Unidos/epidemiologia
20.
Sci Rep ; 12(1): 5732, 2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35388062

RESUMO

Salmonella enterica serovar Typhimurium is a foodborne pathogen causing occasional outbreaks of enteric infections in humans. Salmonella has one of the largest pools of temperate phages in its genome that possess evolutionary significance for pathogen. In this study, we characterized a novel temperate phage Salmonella phage BIS20 (BIS20) with unique tail fiber genes. It belongs to the subfamily Peduovirinae genus Eganvirus and infects Salmonella Typhimurium strain (SE-BS17; Acc. NO MZ503545) of poultry origin. Phage BIS20 was viable only at biological pH and temperature ranges (pH7 and 37 °C). Despite being temperate BIS20 significantly slowed down the growth of host strain for 24 h as compared to control (P < 0.009). Phage BIS20 features 29,477-base pair (bp) linear DNA genome with 53% GC content and encodes for 37 putative ORFs. These ORFs have mosaic arrangement as indicated by its ORF similarity to various phages and prophages in NCBI. Genome analysis indicates its similarity to Salmonella enterica serovar Senftenberg prophage (SEStP) sequence (Nucleotide similarity 87.7%) and Escherichia virus 186 (~ 82.4% nucleotide similarity). Capsid genes were conserved however those associated with tail fiber formation and assembly were unique to all members of genus Eganvirus. We found strong evidence of recombination hotspot in tail fiber gene. Our study identifies BIS20 as a new species of genus Eganvirus temperate phages as its maximum nucleotide similarity is 82.4% with any phage in NCBI. Our findings may contribute to understanding of origin of new temperate phages.


Assuntos
Bacteriófagos , Fagos de Salmonella , Bacteriófagos/genética , Genoma Viral , Humanos , Myoviridae/genética , Nucleotídeos , Prófagos/genética , Salmonella , Fagos de Salmonella/genética , Salmonella typhimurium/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...