Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35.895
Filtrar
1.
Front Cell Infect Microbiol ; 11: 670211, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34222041

RESUMO

The contamination of dental unit waterlines (DUWLs) is a serious problem and directly affects the dental care. This study aims to explore the microbial community of biofilm in DUWL from different specialties and investigate the associated factors. A total of 36 biofilm samples from 18 DUWL of six specialties (i.e., prosthodontics, orthodontics, pediatrics, endodontics, oral surgery, and periodontics) at two time points (i.e., before and after daily dental practice) were collected with a novel method. Genomic DNA of samples was extracted, and then 16S ribosomal DNA (rDNA) (V3-V4 regions) and ITS2 gene were amplified and sequenced. Kruskal-Wallis and Wilcoxon rank test were adopted for statistical analysis. Microbial community with high diversity of bacteria (631 genera), fungi (193 genera), and viridiplantae was detected in the biofilm samples. Proteobacteria was the dominant bacteria (representing over 65.74-95.98% of the total sequences), and the dominant fungi was Ascomycota (93.9-99.3%). Microorganisms belonging to multiple genera involved in human diseases were detected including 25 genera of bacteria and eight genera of fungi, with relative abundance of six genera over 1% (i.e., Acinetobacter, Pseudomonas, Enterobacter, Aspergillus, Candida, and Penicillium). The biofilm microbiome may be influenced by the characteristics of dental specialty and routine work to some extent. The age of dental chair unit and overall number of patients had the strongest impact on the overall bacteria composition, and the effect of daily dental practices (associated with number of patients and dental specialty) on the fungi composition was the greatest. For the first time, biofilm in DUWL related to dental specialty was comprehensively evaluated, with more abundance of bacterial and fungal communities than in water samples. Biofilm accumulation with daily work and multiple kinds of opportunistic pathogen emphasized the infectious risk with dental care and the importance of biofilm control.


Assuntos
Microbiota , Microbiologia da Água , Biofilmes , Criança , Contagem de Colônia Microbiana , Contaminação de Equipamentos , Humanos
2.
Molecules ; 26(11)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34063892

RESUMO

Sea buckthorn (Hippophae rhamnoides L.) is recognized as a valuable source of vitamin C and antioxidants, frequently used as nutraceuticals and cosmeceuticals. In the present study, attempts are made to produce and characterize a novel type of marmalade using sea buckthorn berries processed at 102 °C into marmalade in two combinations, with whole cane or stevia sugar. Changes in the phytochemical profile, antioxidant activity, color, shelf-life, texture, microbiological, and sensorial characteristics were determined. The total carotenoids content in the marmalades were significantly different, with values of 0.91 ± 0.03 mg/g dry weight (DW) in the sample with whole sugar cane (Cz) and 2.69 ± 0.14 mg/g DW in the sample with Stevia sugar (Cs). Significant values of polyphenols were found, of 59.41 ± 1.13 mg GAE/g DW in Cz and 72.44 ± 2.31 mg GAE/g DW in Cs, leading to an antioxidant activity of 45.12 ± 0.001 µMol Trolox/g DW and 118.07 ± 0.01 µMol Trolox/g DW, respectively. Accelerated storage study showed a decrease in all the phytochemicals, however no significant changes were found in antioxidant activity. Values of <100 CFU/g for yeasts and molds and <5 CFU/g for Enterobacteriaceae after 21 days of storage at the room temperature of the marmalades were determined. The sensorial and color results were more than acceptable. Overall, the results highlighted the potential of using sea buckthorn as a potential rich source of bioactive compounds to be used in the sugar-based products manufacturing.


Assuntos
Manipulação de Alimentos , Hippophae/química , Stevia , Açúcares , Antioxidantes/análise , Carotenoides/análise , Contagem de Colônia Microbiana , Enterobacteriaceae/isolamento & purificação , Análise de Alimentos , Microbiologia de Alimentos , Fungos/isolamento & purificação , Compostos Fitoquímicos/análise , Leveduras/isolamento & purificação
3.
Int J Mol Sci ; 22(9)2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-34063173

RESUMO

Recent studies have suggested that flavonoids such as quercetin and probiotics such as Bifidobacterium bifidum (Bf) and Lactobacillus gasseri (Lg) could play a relevant role in inhibiting colon cancer cell growth. Our study investigated the role of dietary supplementation with microencapsulated probiotics (Bf and Lg) along with quercetin in the development of mouse colorectal cancer (CRC). Methods: Adenomatous polyposis coli/multiple intestinal neoplasia (ApcMin/+) mice were fed a standard diet or the same diet supplemented with microencapsulated probiotics (Bf and Lg strains, 107 CFU/100 g food) or both probiotics strains plus microencapsulated quercetin (15 mg/100 g food) for 73 days. Changes in body and organ weights, energy metabolism, intestinal microbiota, and colon tissue were determined. The expression of genes related to the Wnt pathway was also analyzed in colon samples. Results: Dietary supplementation with microencapsulated probiotics or microencapsulated probiotics plus quercetin reduced body weight loss and intestinal bleeding in ApcMin/+ mice. An improvement in energy expenditure was observed after 8 weeks but not after 10 weeks of treatment. A supplemented diet with microencapsulated Bf and Lg reduced the number of aberrant crypt foci (ACF) and adenomas by 45% and 60%, respectively, whereas the supplementation with Bf, Lg and quercetin decreased the number of ACF and adenomas by 57% and 80%, respectively. Microencapsulated Bf and Lg in combination with quercetin could exert inhibition of the canonical Wnt/ß-catenin signaling pathway in the colon of ApcMin/+ mice Conclusions: The administration of microencapsulated Bf and Lg, individually or in combination with quercetin, inhibits the CRC development in ApcMin/+ mice.


Assuntos
Polipose Adenomatosa do Colo/metabolismo , Bifidobacterium bifidum/citologia , Carcinogênese/patologia , Células Imobilizadas/citologia , Neoplasias Colorretais/patologia , Lactobacillus gasseri/citologia , Quercetina/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Carcinogênese/efeitos dos fármacos , Colo/patologia , Contagem de Colônia Microbiana , Neoplasias Colorretais/genética , Metabolismo Energético/efeitos dos fármacos , Fezes/microbiologia , Comportamento Alimentar , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Sangue Oculto , Tamanho do Órgão/efeitos dos fármacos , Probióticos/farmacologia , Via de Sinalização Wnt/efeitos dos fármacos
4.
Int J Food Microbiol ; 351: 109076, 2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34090034

RESUMO

To identify the microbial community and origin of the spoilage flora of bacon, the changes in microbial population numbers and community structure were followed along the processing line, using culture-independent and culture-dependent methods. 16S rRNA gene amplicon sequencing (16S-seq) analysis showed that community complexity and structure significantly differed at different processing stages. Some 428 bacterial groups were ascertained at genus level, and Acinetobacter, Pseudomonas, Psychrobacter, and Brochothrix were the predominant bacteria on raw meats. After curing specimens dominated by Psychrobacter, Weissella, Vibrio, Leuconostoc, Myroides, Acinetobacter, and Lactobacillus, a total of 33 species were identified by traditional microbiological analyses and direct sequence determination methods. Our results indicated that curing should be considered one of the primary factors during various processing steps, presumably contaminating the products directly or indirectly.


Assuntos
Bactérias/isolamento & purificação , Manipulação de Alimentos , Microbiota , Carne de Porco/microbiologia , Animais , Bactérias/classificação , Bactérias/genética , Contagem de Colônia Microbiana , Microbiologia de Alimentos , RNA Ribossômico 16S/genética
5.
Nat Commun ; 12(1): 3960, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34172727

RESUMO

The Greenland Ice Sheet harbours a wealth of microbial life, yet the total biomass stored or exported from its surface to downstream environments is unconstrained. Here, we quantify microbial abundance and cellular biomass flux within the near-surface weathering crust photic zone of the western sector of the ice sheet. Using groundwater techniques, we demonstrate that interstitial water flow is slow (~10-2 m d-1), while flow cytometry enumeration reveals this pathway delivers 5 × 108 cells m-2 d-1 to supraglacial streams, equivalent to a carbon flux up to 250 g km-2 d-1. We infer that cellular carbon accumulation in the weathering crust exceeds fluvial export, promoting biomass sequestration, enhanced carbon cycling, and biological albedo reduction. We estimate that up to 37 kg km-2 of cellular carbon is flushed from the weathering crust environment of the western Greenland Ice Sheet each summer, providing an appreciable flux to support heterotrophs and methanogenesis at the bed.


Assuntos
Biomassa , Camada de Gelo/microbiologia , Carbono/análise , Ciclo do Carbono , Contagem de Colônia Microbiana , Groenlândia , Hidrologia , Camada de Gelo/química , Tempo (Meteorologia)
6.
Food Chem ; 362: 130201, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34090044

RESUMO

The research on a new type of low-cost, less-loss and adjustable sustained antibacterial activity food packaging films with self-activation ability and great industrialization potentiality is of great scientific and technological interest. Herein, a novel chitosan/negatively charged graphitic carbon nitride self-activation bionanocomposite films was prepared by one-step electrostatic self-assembly. First, the antibacterial efficiency of this film could reach to 99.8 ± 0.26% against E. coli and 99.9 ± 0.04% against S. aureus through self-activated under visible light. Second, this film can effectively extend the shelf life of tangerines to 24 days. Hemolysis and cell experiment test proved that this film was safe and nontoxic. Finally, negatively charged graphitic carbon nitride with low-cost can improve the mechanical, thermal and hydrophobic properties of neat chitosan films. This work can provide a new pathway for the preparation of low-cost packaging films with excellent visible light responsive property and sustainable antibacterial activity.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Embalagem de Alimentos/instrumentação , Nanoestruturas/química , Quitosana/química , Citrus , Contagem de Colônia Microbiana , Escherichia coli/efeitos dos fármacos , Luz , Nitrilas/química , Staphylococcus aureus/efeitos dos fármacos , Eletricidade Estática
7.
Int J Mol Sci ; 22(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067069

RESUMO

Banana (Musa spp.), one of the most important fruits worldwide, is generally cold sensitive. In this study, by using the cold-sensitive banana variety Tianbaojiao (Musa acuminate) as the study material, we investigated the effects of Piriformospora indica on banana cold resistance. Seedlings with and without fungus colonization were subjected to 4 °C cold treatment. The changes in plant phenotypes, some physiological and biochemical parameters, chlorophyll fluorescence parameters, and the expression of eight cold-responsive genes in banana leaves before and after cold treatment were measured. Results demonstrated that P. indica colonization reduced the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2) but increased the activities of superoxide dismutase (SOD) and catalase (CAT) and the contents of soluble sugar (SS) and proline. Noteworthily, the CAT activity and SS content in the leaves of P. indica-colonized banana were significant (p < 0.05). After 24 h cold treatment, the decline in maximum photochemistry efficiency of photosystem II (Fv/Fm), photochemical quenching coefficient (qP), efficient quantum yield [Y(II)], and photosynthetic electron transport rate (ETR) in the leaves of P. indica-colonized banana was found to be lower than in the non-inoculated controls (p < 0.05). Moreover, although the difference was not significant, P. indica colonization increased the photochemical conversion efficiency and electron transport rate and alleviated the damage to the photosynthetic reaction center of banana leaves under cold treatment to some extent. Additionally, the expression of the most cold-responsive genes in banana leaves was significantly induced by P. indica during cold stress (p < 0.05). It was concluded that P. indica confers banana with enhanced cold resistance by stimulating antioxidant capacity, SS accumulation, and the expression of cold-responsive genes in leaves. The results obtained from this study are helpful for understanding the P. indica-induced cold resistance in banana.


Assuntos
Basidiomycota/fisiologia , Temperatura Baixa , Resistência à Doença , Endófitos/fisiologia , Musa/enzimologia , Basidiomycota/crescimento & desenvolvimento , Catalase/metabolismo , Clorofila/metabolismo , Contagem de Colônia Microbiana , Eletrólitos/metabolismo , Fluorescência , Regulação da Expressão Gênica de Plantas , Musa/genética , Musa/microbiologia , Peroxidase/metabolismo , Fenótipo , Folhas de Planta/enzimologia , Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Superóxido Dismutase/metabolismo
8.
Molecules ; 26(10)2021 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-34070170

RESUMO

The aim of this study was to investigate the possibility of using Aronia melanocarpa, Chaenomeles superba, and Cornus mas leaf extracts as natural preservatives for pork meat products. Pork sausages were stored in modified atmosphere packaging (MAP) (80% N2 and 20% CO2) at 4 °C for 29 days. The total psychrotrophic counts (TPC) were determined during the storage period, along with the numbers of Enterobacteriaceae and lactic acid bacteria (LAB). The extracts improved the microbial quality of the meat products but to a lesser extent than sodium nitrate (III). They reduced the amounts of Enterobacteriaceae and LAB. The A.melanocarpa leaf extract showed the strongest preservative effect. The bacterial biodiversity of the meat products was investigated based on high-throughput sequencing of the 16S rRNA gene. Two predominant bacteria phyla were identified, Proteobacteria and Firmucutes, mostly consisting of genera Photobacterium, Brochothrix, and Carnobacterium. The extracts also influenced microbial community in sausages decreasing or increasing bacterial relative abundance. The extracts significantly inhibited lipid oxidation and improved the water-holding capacity of the meat, with C. superba extract showing the strongest influence. In addition, A. melanocarpa and C. superba improved the redness (a*) of the sausages. The results of this study show that A. melanocarpa, C. superba, and C. mas leaf extracts can extend the shelf life of meat products stored in MAP at 4 °C.


Assuntos
Cornus/química , Conservação de Alimentos , Photinia/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Carne de Porco/análise , Rosaceae/química , Animais , Atmosfera , Contagem de Colônia Microbiana , Cor , Embalagem de Alimentos , Humanos , Filogenia , Análise de Componente Principal , RNA Ribossômico 16S/genética , Sensação , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
9.
BMC Infect Dis ; 21(1): 509, 2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34059003

RESUMO

BACKGROUND: Readily-available diagnostics do not reliably discriminate between viral and bacterial pediatric uncomplicated pneumonia, both of which are common. Some have suggested that assessment of pneumococcal carriage could be used to identify those children with bacterial pneumonia. The objective of this study was to determine if nasopharyngeal pneumococcal colonization patterns differed between children with definite viral disease, definite bacterial disease, and respiratory disease of indeterminate etiology. METHODS: Three groups of subjects were recruited: children with critical respiratory illness, previously healthy children with respiratory illness admitted to the ward, and previously healthy children diagnosed in the emergency department with non-severe pneumonia. Subjects were categorized as follows: a) viral infection syndrome (eg. bronchiolitis), b) bacterial infection syndrome (ie. pneumonia complicated by effusion/empyema), or c) 'indeterminate' pneumonia. Subjects' nasopharyngeal swabs underwent quantitative PCR testing for S. pneumoniae. Associations between categorical variables were determined with Fisher's exact, chi-square, or logistic regression, as appropriate. Associations between quantitative genomic load and categorical variables was determined by linear regression. RESULTS: There were 206 children in Group 1, 122 children in Group 2, and 179 children in Group 3. Only a minority (227/507, 45%) had detectable pneumococcal carriage; in those subjects, there was no association of quantitative genomic load with age, recruitment group, or disease category. In multivariate logistic regression, pneumococcal colonization > 3 log copies/mL was associated with younger age and recruitment group, but not with disease category. CONCLUSIONS: The nasopharyngeal S. pneumoniae colonization patterns of subjects with definite viral infection were very similar to colonization patterns of those with definite bacterial infection or indeterminate pneumonia. Assessment and quantification of nasopharyngeal pneumococcal colonization does not therefore appear useful to discriminate between acute viral and bacterial respiratory disease; consequently, this diagnostic testing is unlikely to reliably determine which children with indeterminate pneumonia have a bacterial etiology and/or require antibiotic treatment.


Assuntos
Nasofaringe/microbiologia , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/etiologia , Streptococcus pneumoniae/isolamento & purificação , Antibacterianos/uso terapêutico , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/epidemiologia , Canadá/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Contagem de Colônia Microbiana , Estudos Transversais , Humanos , Lactente , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/epidemiologia , Streptococcus pneumoniae/genética , Viroses/diagnóstico , Viroses/tratamento farmacológico , Viroses/epidemiologia
10.
BMC Infect Dis ; 21(1): 513, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34074248

RESUMO

BACKGROUND: In resource-limited settings, sputum smear conversion is used to document treatment response. Many People living with HIV (PLHIV) are smear-negative at baseline. The Xpert MTB/RIF test can indirectly measure bacterial load through cycle threshold (ct) values. This study aimed to determine if baseline Xpert MTB/RIF could predict time to culture negativity in PLHIV with newly diagnosed TB. METHODS: A subset of 138 PLHIV from the 'SOUTH' study on outcomes related to TB and antiretroviral drug concentrations were included. Bacterial load was estimated by Mycobacterium Growth Indicator Tubes (MGIT) culture time-to-positivity (TTP) and Lowenstein Jensen (LJ) colony counts. Changes in TTP and colony counts were analyzed with Poisson Generalised Estimating Equations (GEE) and multilevel ordered logistic regression models, respectively, while time to culture negativity analysed with Cox proportional hazard models. ROC curves were used to explore the accuracy of the ct value in predicting culture negativity. RESULTS: A total of 81 patients (58.7%) were males, median age 34 (IQR 29  ̶ 40) years, median CD4 cell count of 180 (IQR 68  ̶ 345) cells/µL and 77.5% were ART naive. The median baseline ct value was 25.1 (IQR 21.0  ̶ 30.1). A unit Increase in the ct value was associated with a 5% (IRR = 1.05 95% CI 1.04  ̶ 1.06) and 3% (IRR = 1.03 95% CI 1.03  ̶ 1.04) increase in TTP at week 2 and 4 respectively. With LJ culture, a patient's colony grade was reduced by 0.86 times (0R = 0.86 95% CI 0.74  ̶ 0.97) at week 2 and 0.84 times (OR = 0.84 95% CI 0.79  ̶ 0.95 P = 0.002) at week 4 for every unit increase in the baseline ct value. There was a 3% higher likelihood of earlier conversion to negativity for every unit increase in the ct value. A ct cut point ≥28 best predicted culture negativity at week 4 with a sensitivity of 91. 7% & specificity 53.7% while a cut point ≥23 best predicted culture negativity at week 8. CONCLUSION: Baseline Xpert MTB/RIF ct values predict sputum conversion in PLHIV on anti-TB treatment. Surrogate biomarkers for sputum conversion in PLHIV are still a research priority.


Assuntos
Carga Bacteriana/métodos , Infecções por HIV/epidemiologia , Mycobacterium tuberculosis/isolamento & purificação , Escarro/microbiologia , Tuberculose Pulmonar/diagnóstico , Adulto , Antirretrovirais/sangue , Antituberculosos/uso terapêutico , Contagem de Linfócito CD4 , Contagem de Colônia Microbiana , Feminino , Infecções por HIV/sangue , Humanos , Masculino , Técnicas de Amplificação de Ácido Nucleico , Razão de Chances , Estudos Retrospectivos , Sensibilidade e Especificidade , Tuberculose Pulmonar/tratamento farmacológico , Tuberculose Pulmonar/epidemiologia , Uganda/epidemiologia
11.
Int J Food Microbiol ; 352: 109267, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34102464

RESUMO

The use of bacteriocins is a promising alternative to improve food security through the biocontrol of food pathogens and spoilage microorganisms. Gram-negative produced microcin J25(G12Y), known as (MccJ25(G12Y)) is a variant of the well-studied and characterized antimicrobial peptide, microcin J25 (MccJ25). In the present work, we explored the activity of this microcin against Gram-negative bacteria linked to foodborne diseases. We evaluated the in vitro antimicrobial activity of MccJ25(G12Y) in solid medium against a collection of pathogenic and food-altering strains and studied its activity and stability in meat and dairy food systems. We show that MccJ25(G12Y) exhibited the same in vitro antimicrobial spectrum as its parental microcin (MccJ25) against different Gram-negative foodborne pathogens and spoilage strains. We highlight that low concentrations of MccJ25(G12Y) between 0.45 and 29.4 µM were able to inhibit a substantial number of pathogens, including Salmonella, Escherichia, Shigella and Enterobacter genus. We also demonstrate the antimicrobial effectiveness of the peptide against Escherichia coli O157:H7 NCTC 12900, Enterobacter cloacae CECT 194, and Salmonella enterica CECT 4396 in fish and beef burgers and yogurt. MccJ25(G12Y) was added or not to food matrices inoculated with the foodborne pathogens at 105 CFU/g or mL. Afterward, food products were stored at 4 °C and selective media for the specific enumeration were used to determine the antimicrobial susceptibility of each pathogen to MccJ25(G12Y). The viability of the three pathogens was significantly reduced in the different food biological environments. In yogurt, the peptide decreased E. coli numbers on day 5 by about 4 log 10 CFU/mL as compared to non-treated samples. For S. enterica and E. cloacae no viable cells were detected at the end of the treatment. Adding MccJ25(G12Y) to fish burgers decreased E. cloacae numbers during storage 2 log10 CFU/g on the first day, reaching a difference of about 5 log 10 CFU/g after 10 days compared to non-treated control. Finally, the peptide decreased E. coli O157:H7 numbers on the beef burgers samples during storage on day 10 by about 3 log 10 CFU/g as compared to non-treated samples. The stability analysis demonstrated that MccJ25(G12Y) is capable of remaining active in these food matrices for a considerable time during the storage at refrigeration temperatures. These results reinforce the studies on the potential applicability of this microcin as a biopreservative in the food industry.


Assuntos
Bacteriocinas/farmacologia , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Bactérias Gram-Negativas/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Contagem de Colônia Microbiana , Escherichia coli O157/efeitos dos fármacos , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Salmonella/efeitos dos fármacos
12.
Int J Food Microbiol ; 352: 109265, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34116257

RESUMO

Listeria monocytogenes is a potentially fatal foodborne pathogen that can be found in various ready-to-eat (RTE) products. It tolerates adverse conditions such as high salt concentrations and refrigerated storage, thus, the elimination of the pathogen in food processing often relies on heat processing. The objective of this study was to create a model to predict the effect of salt on heat tolerance of L. monocytogenes in meat and seafood products during heat treatments conducted at 57 to 65 °C to reduce numbers by ≥3 log10 cycles. Salt concentrations, up to 6% in the water phase (WPS%), were applied to cover a variety of lightly salted RTE meat and seafood products. The experimental work involved samples of ground pork tenderloin, ground chicken breast fillet and skinned, ground salmon fillet adjusted to different WPS% i.e., 3.6 and 5.2 WPS% for pork samples, 2.0, 3.0, 3.5 and 6.0 WPS% for chicken samples and 3.0 and 6.0 WPS% for salmon samples. All samples were inoculated with late-stationary phase L. monocytogenes cultures. For pork samples, a two-strain mixture of a pork isolate (MS22254) and an environmental isolate (MS22246) was applied. For chicken and salmon samples, a seafood isolate (MS22258) and isolate MS22246 was applied as single cultures. Samples were vacuum-packed in sterile bags, immerged in water bath, and held at constant temperatures of 57, 60 and 65 °C for pork samples and 58, 61 and 62.5 °C for chicken and salmon samples. For survivor curves, where at least 3 log10-reduction were obtained, heat tolerance was expressed as decimal reduction times, D-values. D-values were observed to increase with increasing WPS%. The effect of salt on heat tolerance of L. monocytogenes was defined as the relative increase (RI-value) in D-value obtained when salt had been added to the food. The effect of WPS% on RI-values was independent of heating temperatures, foods and strains. For secondary modelling, RI-values were transformed using the natural logarithm, ln(RI) and fitted to a linear model as a function of WPS%. Model validation, with 56 independent values collected from the scientific literature, resulted in bias and accuracy factors of 0.89 and 1.26, respectively, suggesting acceptable performance with tendency to slightly under-predict. The developed predictive model can be used to guide the design of heat processes for manufacturers of lightly preserved and mildly processed meat and seafood products requiring more than 3 log10 reduction of L. monocytogenes to ensure safety.


Assuntos
Produtos Pesqueiros/microbiologia , Manipulação de Alimentos/métodos , Listeria monocytogenes/efeitos dos fármacos , Produtos da Carne/microbiologia , Modelos Biológicos , Cloreto de Sódio/farmacologia , Termotolerância/efeitos dos fármacos , Animais , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Microbiologia de Alimentos , Temperatura Alta
13.
Int J Food Microbiol ; 352: 109281, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34126526

RESUMO

Food-borne pathogenic bacteria are dispersed throughout the entire chain of the food industry. However, many food preservatives are limited by poor biocompatibility such as cumulative poisoning. The antimicrobial peptide is increasingly regarded as a promising preservative in food research due to its high bioactivity and low cytotoxicity. In this study, thirteen peptides were designed, synthesized, and screened for application as food preservatives. One of them, termed zp65, whose sequence is GIOAOIIIOIOO-NH2, demonstrated potent bactericidal effect against common Gram-negative strains including enterohemorrhagic Escherichia coli, Salmonella, and Citrobacter freundii. Encouragingly, zp65 showed negligible cytotoxicity to both mammalian cells and Galleria mellonella larvae. Peptide zp65 was prone to form α-helix structure in amphiphilic environments, facilitating its affinity with bacterial membrane. Furthermore, the proteolytic stability of zp65 was much higher than its derivatives consisting of totally natural amino acids. Isothermal titration calorimetry indicated that zp65 has a strong binding affinity to lipopolysaccharide with Kd = 1.3 µM, suggesting its possible action target on the bacterial envelope. Mechanistic studies revealed that this peptide also influenced the membrane potential of E.coli O157:H7 (O157) in a dose-dependent manner. Surprisingly, peptide zp65 did not induce disruption of membrane permeability even at a higher concentration of 4-fold minimal inhibitory concentration. By employing confocal microscopy, peptide zp65 labeled by fluorescein isothiocyanate mainly aggregated on the bacterial membrane. These results suggested that the bactericidal mode of action of zp65 is likely attributed to depolarization of the cell membrane. The minced lean beef experiment indicated that the maximum reduction of O157 reached 1.46 log colony-forming unit (CFU) per gram on day 1 after zp65 treatment at the dosage of 40 µg/g. Compared with the untreated cooked beef sample, the CFU of the zp65-treated group remained at a much lower level after 10-day storage. Subsequently, treatment with zp65 at concentrations above 32 µM also significantly reduced O157 viable counts in fresh tomato juice. And the zp65 treatment could rescue about 40% of Galleria mellonella larvae injected with O157-contaminated tomato juice. The peptide zp65 exhibits great potential and deserves further study as a candidate for food preservative.


Assuntos
Escherichia coli O157/efeitos dos fármacos , Microbiologia de Alimentos , Conservantes de Alimentos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Animais , Antibacterianos/farmacologia , Bovinos , Contagem de Colônia Microbiana , Larva/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Mariposas/efeitos dos fármacos , Ornitina/química , Carne Vermelha/microbiologia
14.
Artigo em Inglês | MEDLINE | ID: mdl-34065424

RESUMO

Water in dental unit waterlines (DUWL) represents a risk for vulnerable patients if its microbiological quality is not controlled. The aim of this prospective study was to evaluate two systems for its management under real conditions: Hygowater® and IGN Calbenium®. Samples of the output water of DUWL were obtained for 5 previously contaminated units connected to Hygowater®, and 5 non-contaminated units connected to IGN Calbenium®, which was already effective for more than 1 year, as a control group. Samples were regularly collected up to 6 months after the implementation of Hygowater®, and were then cultured and analyzed. With IGN Calbenium®, except for a technical problem and a sample result in one unit at 6 months (Heterotrophic Plate Count (HPC) at 37 °C of 66 colony forming units (cfu)/mL), the results showed an absence of contamination. Hygowater® took a couple of weeks to be effective on initially contaminated DUWL (over 200 cfu/mL for all the units), then showed its efficacy for 2 months (HPC at 37 °C with a mean of 40.2 ufc/mL, and HPC at 22 °C with a mean of 0.2 ufc/mL). At 6 months, results were satisfactory for HPC at 22 °C (mean of 12 ufc/mL), but HPC at 37 °C gave non-satisfactory results for 4 of the 5 units (mean of 92.2 ufc/mL). Both systems have an effect on the microbiological quality of DUWL. IGN Calbenium® appears to be more reliable on a long-term basis.


Assuntos
Microbiologia da Água , Água , Biofilmes , Contagem de Colônia Microbiana , Equipamentos Odontológicos , Contaminação de Equipamentos , Humanos , Estudos Prospectivos
15.
Poult Sci ; 100(7): 101206, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34111613

RESUMO

Peroxyacetic acid (PAA) is a widely used antimicrobial during poultry processing that requires to be shipped in a concentrated solution, stored under hazardous conditions and diluted for use. On-site PAA generation using nonhazardous ingredients can help eliminate transportation and storage issues at the processing plant and reduce the risk of occupational hazards. The objective of the proposed research was to 1) evaluate the efficacy of on-site generated PAA in reducing Salmonella and Campylobacter populations compared to the commercially available PAA stock solutions and 2) to perform color measurements to evaluate any deviations between treatments. PAA solutions at 50 and 100 ppm were used for treating the chicken wings. Fresh chicken wings (0.45 kg) were inoculated with a cocktail of nalidixic acid resistant Salmonella Typhimurium (STNR) and gentamicin resistant Campylobacter coli (CCGR) and immersed in PAA solutions (50 and 100 ppm) adjusted to pH 8.5 and 10.0 or 10.5, for either 10 s or 60 min. Treated chicken wings were rinsed for 1 min in chilled BPW (100 mL), serially diluted and plated on APC Petrifilm for Salmonella, spread plated on Campy-cefex agar supplemented with gentamicin (200 ppm) for Campylobacter enumeration. Immersion of chicken wings in 100 ppm PAA for 60 min irrespective of pH levels and PAA solutions resulted in greater microbial reductions (P < 0.05) of Salmonella by 1.68 and 1.42 log CFU/mL for SaniDate, 1.82 and 1.83 log CFU/mL for OxyFusion (on-site generated). For the same treatments, Campylobacter reductions of 1.59 and 1.36 log CFU/mL for SaniDate, 1.63 and 1.71 log CFU/mL for OxyFusion were achieved. The antimicrobial efficiency of PAA was not affected by pH and type of PAA solution. No significant differences (P > 0.05) in color were observed between treatments and controls. On-site generated PAA provides poultry processors an effective, safer, and less hazardous alternative to commercially available PAA solutions, ensuring poultry workers' health and safety.


Assuntos
Campylobacter , Ácido Acético , Animais , Galinhas , Contagem de Colônia Microbiana/veterinária , Manipulação de Alimentos , Microbiologia de Alimentos , Carne , Ácido Peracético , Tecnologia
16.
Ars pharm ; 62(2): 175-181, abr.-jun. 2021. tab
Artigo em Espanhol | IBECS | ID: ibc-202443

RESUMO

INTRODUCCIÓN: Los desinfectantes son utilizados en las empresas farmacéuticas para garantizar la disminución o eliminación de los microorganismos que puedan estar presentes en las líneas de producción, equipamiento, personal o ambiente. Aunque el fabricante garantiza la efectividad de los mismos es necesario probarlos en el entorno farmacéutico donde se van a utilizar. MÉTODO: se evaluaron tres desinfectantes, NDP-Surfaplus en concentración del 70%, NDP-Surfaclin en concentración del 2% y 0,5% y Tristel Jet gel activado a la concentración 0,12%. Se practicaron hisopados antes y después de la aplicación del desinfectante a tramos de superficies de paredes, pisos, mesetas de mármol y fregaderos de acero inoxidable, De cada superficie se escogieron los tramos que presentaban mayor dificultad para realizar los procesos de limpieza y desinfección. El método de conteo utilizado fue el de placa vertida. RESULTADOS: se demostró que los desinfectantes cumplieron con la reducción del 90% de la población microbiana inicial, exceptuando la concentración del 0,5% del desinfectante NDP-Surfaclin. Se aisló mayor número de microorganismos en las superficies que tenían tendencia a formar poros debido a la erosión de los procesos de limpieza y desinfección, así mismo se demostró que los desinfectantes tenían una mejor actividad en las superficies de acero inoxidable. CONCLUSIONES: se demostró la efectividad de los desinfectantes en el entorno farmacéutico de la línea de formulación aprobándose su uso para los procesos de limpieza y desinfección. El desinfectante de mejor actividad fue el NDP-Surfaplus a la concentración del 70%


INTRODUCTION: Disinfectants are used in pharmaceutical companies to guarantee the reduction or elimination of microorganisms that may be present in production lines, equipment, personnel or the environment. Although the manufacturer guarantees their effectiveness, it is necessary to test them in the pharmaceutical environment where they are to be used. METHOD: Three disinfectants were evaluated, NDP-Surfaplus in 70% concentration, NDP-Surfaclin in 2% and 0,5% concentration and Tristel Jet gel activated at 0,12% concentration. Swabs were performed before and after the application of the disinfectant to sections of wall surfaces, floors, marble plateaus and stainless-steel sinks. From each surface the sections that were most difficult to carry out the cleaning and disinfection processes were chosen. The counting method used was the poured plate method. RESULTS: The disinfectants were shown to meet the stipulated acceptance criteria with a 90% reduction in the initial microbial population, except for the 0,5% concentration of the NDP-Surfaclin disinfectant. A greater number of microorganisms were isolated on surfaces that had a tendency to form pores due to erosion from cleaning and disinfection processes, and it was also shown that disinfectants had a better activity on stainless steel surfaces. CONCLUSIONS: The effectiveness of disinfectants in the pharmaceutical environment of the formulation line was demonstrated, approving their use for cleaning and disinfection processes. The best-performing disinfectant was NDP-Surfaplus at the 70% concentration


Assuntos
Dióxido de Cloro , Desinfetantes/farmacologia , Farmácia , Desinfecção/métodos , Ambiente de Instituições de Saúde , Desinfetantes/química , Contagem de Colônia Microbiana , Bactérias/efeitos dos fármacos , Reprodutibilidade dos Testes , Aço Inoxidável
17.
Orthopedics ; 44(3): e414-e416, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34039206

RESUMO

One method of preventing surgical-site infection is lowering intraoperative environmental contamination. The authors sought to evaluate their hospital's operating room (OR) contamination rate and compare it with the remainder of the hospital. They tested environmental contamination in preoperative, intraoperative, and postoperative settings for a total joint arthroplasty patient. A total of 190 air settle plates composed of trypsin soy agar were placed in 19 settings within the hospital. Locations included the OR with light and heavy traffic, with and without masks, jackets, and shoe covers; the substerile room; OR hallways; the sterile equipment processing center; preoperative areas; post-anesthesia care units; orthopedic floors; the emergency department; OR locker rooms and restrooms; a resident's home; and controls. The trypsin soy agar plates were incubated at 36 °C for 48 hours. Colony counts were performed for each plate. Average colony-forming units (CFUs) were calculated in each setting. The highest CFUs were in the OR locker room, at 28 CFUs per plate per hour. Preoperative and post-anesthesia care unit holding areas were 7.4 CFUs and 9.6 CFUs, respectively. The main orthopedic surgical ward had 10.0 CFUs per plate per hour, whereas the VIP hospital ward had 17.0 CFUs per plate per hour. All OR environments had low CFUs. A live OR had slightly higher CFUs than settings without OR personnel. In comparison with the local community household, the OR locker room, restrooms, hospital orthopedic wards, emergency department, preoperative holding, post-anesthesia care unit, and OR hallway all had higher airborne contamination. On the basis of these results, the authors recommend environmental sampling as a simple, fast, inexpensive tool for monitoring airborne contamination. [Orthopedics. 2021;44(3):e414-e416.].


Assuntos
Microbiologia do Ar , Hospitais , Salas Cirúrgicas , Infecção da Ferida Cirúrgica/prevenção & controle , Artroplastia de Substituição , Contagem de Colônia Microbiana , Serviço Hospitalar de Emergência , Humanos , Quartos de Pacientes , Roupa de Proteção/microbiologia , Equipamentos Cirúrgicos/microbiologia , Toaletes
18.
New Microbiol ; 44(2): 117-124, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33978196

RESUMO

The highly structured biofilms on the surface of internal tubing are regarded as the most important source of water pollution in the dental unit waterline (DUWL). Herein, the study aimed to evaluate the anti-biofilm effect of combined application of chlorine-containing disinfectant with multi-enzyme detergent in the dental unit waterline. Six dental units were included and randomly divided into two groups - Group A was treated with chlorine-containing disinfectant and multi-enzyme detergent; Group B was treated only with chlorine-containing disinfectant as control. All groups were treated once a day for four weeks. The anti-biofilm effect was evaluated by heterotrophic plate counts in output water, structure of biofilms, and fluorescence density of biofilms before and after treatment. Abundant opportunistic bacteria forming dense biofilms were observed before treatment. After one week, scanning electron microscopy showed the extracellular polymeric substance of biofilms in Group A was partially destroyed. The biofilms of Group A were completely removed in the third week, while the biofilms of Group B were still present. The combined application of chlorine-containing disinfectant and multi-enzyme detergent achieved a satisfactory effect on biofilms removal, demonstrating this strategy may play a significant role in reducing contamination in the dental clinic.


Assuntos
Desinfetantes , Biofilmes , Cloro , Contagem de Colônia Microbiana , Equipamentos Odontológicos , Detergentes/farmacologia , Desinfetantes/farmacologia , Contaminação de Equipamentos , Matriz Extracelular de Substâncias Poliméricas , Humanos , Microbiologia da Água
19.
J Dairy Sci ; 104(8): 8568-8581, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34024598

RESUMO

The present study describes the effects of modified atmosphere packaging (MAP) on shelf-life extension, chemical, microbiological, and sensory properties of Domiati cheese. Five different MAP were studied [10% CO2/90% N2 (G1), 15% CO2/85% N2 (G2), 25% CO2/75% N2 (G3), 100% CO2 (G4), and 100% N2 (G5)]. Control samples were packaged in air (CA) and under vacuum. In both groups of cheeses, chemical analysis was significantly affected by MAP during cold storage. Ripening indexes were significantly affected by MAP during cold storage. Microbiological data showed that G4, followed by G5, were the most effective groups inhibiting the growth of total aerobic mesophilic and psychrotrophic bacteria, and yeasts and molds until the end of storage. Sensory evaluation was significantly affected by MAP and storage period, at 45 d CA cheese samples were judged as unacceptable. The best sensory properties were obtained in G5, G4, and G3 treatments, and recorded a relatively higher sensory evaluation scores. The best shelf-life extension was obtained in G5, G4, and G3 treatments.


Assuntos
Queijo , Animais , Atmosfera , Contagem de Colônia Microbiana/veterinária , Microbiologia de Alimentos , Embalagem de Alimentos , Conservação de Alimentos
20.
Int J Food Microbiol ; 349: 109232, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34022615

RESUMO

Biofilms are formed by microorganisms protected by a self-produced matrix, most often attached to a surface. In the food processing environments biofilms endanger the product safety by the transmission of spoilage and pathogenic bacteria. In this study, we characterised the biofilm formation of the following eleven strains isolated from biofilms in a meat-processing environment: Acinetobacter harbinensis BF1, Arthrobacter sp. BF1, Brochothrix thermosphacta BF1, Carnobacterium maltaromaticum BF1, Kocuria salsicia BF1, Lactococcus piscium BF1, Microbacterium sp. BF1, Pseudomonas fragi BF1, Psychrobacter sp. BF1, Rhodococcus erythropolis BF1, Stenotrophomonas sp. BF1. We applied whole- genome sequencing and subsequent genome analysis to elucidate genetic features associated with the biofilm lifestyle. We furthermore determined the motility and studied biofilm formation on stainless steel using a static mono-species biofilm model mimicking the meat processing environment. The biomass and the EPS components carbohydrates, proteins and extracellular DNA (eDNA) of the biofilms were investigated after seven days at 10 °C. Whole-genome analysis of the isolates revealed that all strains except the Kocuria salsicia BF1 isolate, harboured biofilm associated genes, including genes for matrix production and motility. Genes involved in cellulose metabolism (present in 82% of the eleven strains) and twitching motility (present in 45%) were most frequently found. The capacity for twitching was confirmed using plate assays for all strains except Lactococcus piscium BF1, which showed the lowest motility behaviour. Differences in biofilm forming abilities could be demonstrated. The bacterial load ranged from 5.4 log CFU/cm2 (Psychrobacter sp. isolate) to 8.7 log CFU/cm2 (Microbacterium sp. isolate). The amount of the matrix components varied between isolates. In the biofilm of six strains we detected all three matrix components at different levels (carbohydrates, proteins and eDNA), in two only carbohydrates and eDNA, and in three only carbohydrates. Carbohydrates were detected in biofilms of all strains ranging from 0.5 to 4.3 µg glucose equivalents/cm2. Overall, the Microbacterium sp. strain showed the highest biofilm forming ability with high bacterial load (8.7 log CFU/cm2) and high amounts of carbohydrates (2.2 µg glucose equivalents/cm2), proteins (present in all experiments) and eDNA (549 ng/cm2). In contrast, Brochothrix thermosphacta was a weak biofilm former, showing low bacterial load and low levels of carbohydrates in the matrix (6.2 log CFU/cm2 and 0.5 µg glucose equivalents/cm2). This study contributes to our understanding of the biofilm forming ability of bacteria highly abundant in the meat processing environment, which is crucial to develop strategies to prevent and reduce biofilm formation in the food producing environment.


Assuntos
Bactérias/isolamento & purificação , Biofilmes/crescimento & desenvolvimento , Carne/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Matriz Extracelular de Substâncias Poliméricas/química , Matriz Extracelular de Substâncias Poliméricas/genética , Microbiologia de Alimentos , Indústria de Processamento de Alimentos , Genoma Bacteriano/genética , Locomoção/genética , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...