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1.
Int J Nanomedicine ; 16: 1819-1836, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33707942

RESUMEN

Background: The development of vaccines is a promising and cost-effective strategy to prevent emerging multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) infections. The purpose of this study was to prepare a multiepitope peptide nanovaccine and evaluate its immunogenicity and protective effect in BALB/c mice. Methods: The B-cell and T-cell epitopes of Omp22 from A. baumannii were predicted using bioinformatics methods and identified by immunological experiments. The optimal epitopes were conjugated in series by 6-aminocaproic acid and chemically synthesized multiepitope polypeptide rOmp22. Then, rOmp22 was encapsulated by chitosan (CS) and poly (lactic-co-glycolic) acid (PLGA) to prepare CS-PLGA-rOmp22 nanoparticles (NPs). The immunogenicity and immunoprotective efficacy of the vaccine were evaluated in BALB/c mice. Results: CS-PLGA-rOmp22 NPs were small (mean size of 272.83 nm) with apparently spherical structures, positively charged (4.39 mV) and nontoxic to A549 cells. A high encapsulation efficiency (54.94%) and a continuous slow release pattern were achieved. Compared with nonencapsulated rOmp22, CS-PLGA-rOmp22 immunized BALB/c mice induced higher levels of rOmp22-specific IgG in serum and IFN-γ in splenocyte supernatant. Additionally, lung injury and bacterial burdens in the lung and blood were suppressed, and potent protection (57.14%-83.3%) against acute lethal intratracheal A. baumannii challenge was observed in BALB/c mice vaccinated with CS-PLGA-rOmp22. Conclusion: CS-PLGA-rOmp22 NPs elicited specific IgG antibodies, Th1 cellular immunity and protection against acute lethal intratracheal A. baumannii challenge. Our results indicate that this nanovaccine is a desirable candidate for preventing A. baumannii infection.


Asunto(s)
Infecciones por Acinetobacter/inmunología , Acinetobacter baumannii/inmunología , Vacunas Bacterianas/inmunología , Quitosano/química , Epítopos/inmunología , Nanopartículas/química , Péptidos/inmunología , Copolímero de Ácido Poliláctico-Ácido Poliglicólico/química , Células A549 , Infecciones por Acinetobacter/sangre , Infecciones por Acinetobacter/microbiología , Secuencia de Aminoácidos , Animales , Anticuerpos Antibacterianos/inmunología , Carga Bacteriana , Peso Corporal , Epítopos/química , Femenino , Humanos , Inmunidad Humoral , Inmunización , Inmunoglobulina G/inmunología , Interferón gamma/metabolismo , Interleucina-4/metabolismo , Pulmón/inmunología , Pulmón/microbiología , Pulmón/patología , Ratones , Ratones Endogámicos BALB C , Nanopartículas/ultraestructura , Péptidos/química , Proteínas Recombinantes/aislamiento & purificación , Bazo/patología , Análisis de Supervivencia
2.
Sci Rep ; 11(1): 5887, 2021 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-33723303

RESUMEN

Based on the current knowledge of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) transmission, wearing a mask has been recommended during the COVID-19 pandemic. Bacterial filtration efficiency (BFE) measurements enable designing and regulating medical masks to prevent bioaerosol dissemination; however, despite the simplicity of these measurements, several scientific questions remain unanswered regarding BFE tests. Here, we investigated (1) the impact of substituting 100-mm Petri dishes with 90-mm disposable Petri dishes, (2) the impact of colony-counting methods on the bioaerosol aerodynamic size, and (3) the impact of colony-counting methods on the total viable particle counts. We demonstrated that disposable 90-mm Petri dishes can be used to replace the 100-mm dishes. We also showed that an automatic high-resolution colony counter can be used to directly count viable particles on collection substrates and to measure the bioaerosol size parameters. Our results enable possible modernization of the outdated testing methods recommended in the US and European standards for BFE measurements. Specifically, use of a modernized colony counter should be clearly regulated and permitted to avoid the counting of positive holes. The median aerodynamic diameter appears to be the most relevant parameter for characterizing bioaerosol size.


Asunto(s)
Bacterias , Filtración/normas , Máscaras/normas , Carga Bacteriana , Microbiología Ambiental , Filtración/métodos , Humanos , Máscaras/microbiología , Tamaño de la Partícula , Porosidad
3.
Medicine (Baltimore) ; 100(10): e24924, 2021 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-33725852

RESUMEN

ABSTRACT: Orthodontic treatment can lead to microbial-induced gingival inflammation and aseptic periodontal inflammations. The aim of this study was to investigate the relationship between salivary pro-inflammatory cytokines levels with gingival health status and oral microbe loads among patients undergoing orthodontic treatment.The present investigation was a cross-sectional study among a sample of 111 consecutive orthodontic patients (mean age 18.4 ±â€Š4.4 years). Clinical examinations were conducted to assess the gingival health status employing the Modified Gingival Index, Gingival Bleeding Index, and Plaque Index. Salivary microbiological assessments of total aerobic and anaerobic bacteria count, streptococci count, and lactobacilli count were undertaken. Saliva immunological assessments included Interleukin-1Beta (IL-1ß) and macrophage migration inhibitory factor (MIF) ELISA assays.The mean ±â€Šstandard deviation of salivary IL-1ß was 83.52 ±â€Š85.62 pg/ml and MIF was 4.12 ±â€Š0.96 ng/ml. Moderate positive correlations were found between salivary IL-1ß levels and total aerobic and anaerobic bacteria count, streptococci count, and lactobacilli count (r = 0.380-0.446, P < .001), and weak positive correlations between salivary MIF levels and total salivary aerobic and anaerobic bacteria counts (r = 0.249-0.306, P < .01) were observed. A positive correlation was found between salivary IL-1ß levels and Bleeding Index (r = 0.216, P < .05).The level of salivary IL-1ß positively correlates with oral bacterial load among orthodontic patients; the relationship between inflammatory cytokines and oral microflora deserved further study.


Asunto(s)
Gingivitis/diagnóstico , Interleucina-1beta/análisis , Aparatos Ortodóncicos/efectos adversos , Saliva/química , Adolescente , Carga Bacteriana , Estudios Transversales , Femenino , Encía/inmunología , Encía/microbiología , Gingivitis/inmunología , Gingivitis/microbiología , Gingivitis/prevención & control , Humanos , Interleucina-1beta/inmunología , Oxidorreductasas Intramoleculares/análisis , Oxidorreductasas Intramoleculares/inmunología , Factores Inhibidores de la Migración de Macrófagos/análisis , Factores Inhibidores de la Migración de Macrófagos/inmunología , Masculino , Microbiota/inmunología , Antisépticos Bucales/administración & dosificación , Adulto Joven
4.
BMC Infect Dis ; 21(1): 238, 2021 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-33663408

RESUMEN

BACKGROUND: The sputum smear bacilliary load is a fundamental indicator of the level of infectiousness in DR-TB patients. However, evidence on DR-TB sputum smear grading and its factors in the study setting is limited. This study was aimed to determine the level of sputum smear grading and associated factors among DR-TB patients in Ethiopia. METHODS: This was an institution based cross-sectional study on 520 bacteriological confirmed pulmonary DR-TB patients from September 2010 to December 2017 in the northwest Ethiopia. Epidata 4.2.00 and SPSS 20 were used for data entry and management, respectively. Ordinary logistic regression was fitted. A cut of p-value less than 0.05 in the multivariable ordinary logistic regression was considered to declare statistically significant variables. RESULTS: Of all 520 bacteriological confirmed pulmonary DR-TB patients; 34.42% had 3+, 15.77% had 2+, 18.27% had 1+, 15.19% had scanty, and 16.35% had negative sputum smear grading results. The odds of having higher sputum smear grades were significantly associated with the patient's educational status of secondary (Adjusted Odds Ratio (AOR) = 0.43, 95% Confidence Interval (CI): 0.21, 0.89), body mass index of 16 to 18.49 kg/m2 (AOR = 1.81, 95%CI: 1.16, 2.84), and TB treatment history of two and more times (AOR = 1.78, 95%CI: 1.24, 2.55). CONCLUSIONS: More than a third of the bacteriological confirmed pulmonary DR-TB patients in the study setting was highly infectious with the highest bacillary load. The odds of having a high bacillary load were significantly associated with the patient's TB treatment history, nutritional, and educational status.


Asunto(s)
Esputo/microbiología , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Adulto , Carga Bacteriana , Estudios Transversales , Etiopía/epidemiología , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Tuberculosis Resistente a Múltiples Medicamentos/patología
5.
BMC Infect Dis ; 21(1): 209, 2021 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-33632129

RESUMEN

BACKGROUND: Urinary tract infection (UTI) is diagnosed combining urinary symptoms with demonstration of urine culture growth above a given threshold. Our aim was to compare the diagnostic accuracy of Urine Flow Cytometry (UFC) with urine test strip in predicting bacterial growth and in identifying contaminated urine samples, and to derive an algorithm to identify relevant bacterial growth for clinical use. METHODS: Species identification and colony-forming unit (CFU/ml) quantification from bacterial cultures were matched to corresponding cellular (leucocytes/epithelial cells) and bacteria counts per µl. Results comprise samples analysed between 2013 and 2015 for which urine culture (reference standard) and UFC and urine test strip data (index tests, Sysmex UX-2000) were available. RESULTS: 47,572 urine samples of 26,256 patients were analysed. Bacteria counts used to predict bacterial growth of ≥105 CFU/ml showed an accuracy with an area under the receiver operating characteristic curve of > 93% compared to 82% using leukocyte counts. The relevant bacteriuria rule-out cut-off of 50 bacteria/µl reached a negative predictive value of 98, 91 and 89% and the rule-in cut-off of 250 bacteria/µl identified relevant bacteriuria with an overall positive predictive value of 67, 72 and 73% for microbiologically defined bacteriuria thresholds of 105, 104 or 103 CFU/ml, respectively. Measured epithelial cell counts by UFC could not identify contaminated urine. CONCLUSIONS: Prediction of a relevant bacterial growth by bacteria counts was most accurate and was a better predictor than leucocyte counts independently of the source of the urine and the medical specialty ordering the test (medical, surgical or others).


Asunto(s)
Bacteriuria/diagnóstico , Citometría de Flujo/métodos , Urinálisis/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Carga Bacteriana , Bacteriuria/microbiología , Bacteriuria/orina , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Tiras Reactivas , Estándares de Referencia , Sensibilidad y Especificidad , Urinálisis/normas , Infecciones Urinarias/diagnóstico , Infecciones Urinarias/microbiología , Infecciones Urinarias/orina , Adulto Joven
6.
Nat Commun ; 12(1): 1141, 2021 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-33602926

RESUMEN

The composition of the gastrointestinal microbiota influences systemic immune responses, but how this affects infectious disease pathogenesis and antibiotic therapy outcome is poorly understood. This question is rarely examined in humans due to the difficulty in dissociating the immunologic effects of antibiotic-induced pathogen clearance and microbiome alteration. Here, we analyze data from two longitudinal studies of tuberculosis (TB) therapy (35 and 20 individuals) and a cross sectional study from 55 healthy controls, in which we collected fecal samples (for microbiome analysis), sputum (for determination of Mycobacterium tuberculosis (Mtb) bacterial load), and peripheral blood (for transcriptomic analysis). We decouple microbiome effects from pathogen sterilization by comparing standard TB therapy with an experimental TB treatment that did not reduce Mtb bacterial load. Random forest regression to the microbiome-transcriptome-sputum data from the two longitudinal datasets reveals that renormalization of the TB inflammatory state is associated with Mtb pathogen clearance, increased abundance of Clusters IV and XIVa Clostridia, and decreased abundance of Bacilli and Proteobacteria. We find similar associations when applying machine learning to peripheral gene expression and microbiota profiling in the independent cohort of healthy individuals. Our findings indicate that antibiotic-induced reduction in pathogen burden and changes in the microbiome are independently associated with treatment-induced changes of the inflammatory response of active TB, and the response to antibiotic therapy may be a combined effect of pathogen killing and microbiome driven immunomodulation.


Asunto(s)
Microbioma Gastrointestinal , Inflamación/microbiología , Inflamación/patología , Tuberculosis/complicaciones , Tuberculosis/microbiología , Adulto , Algoritmos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Antituberculosos/farmacología , Antituberculosos/uso terapéutico , Carga Bacteriana/efectos de los fármacos , Biodiversidad , Estudios de Casos y Controles , Estudios de Cohortes , Microbioma Gastrointestinal/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Inflamación/complicaciones , Modelos Biológicos , Reproducibilidad de los Resultados , Tuberculosis/tratamiento farmacológico , Tuberculosis/patología
7.
Int J Food Microbiol ; 340: 109051, 2021 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-33485099

RESUMEN

Freezing broiler carcasses, industrially or at home, not only delays spoilage, but also is expected to increase food safety by hampering growth of food pathogens. However, detailed knowledge on microbial changes after a short or longer freezing period of fresh broiler meat in home freezing setting is lacking and no comparison between different freezing periods has been published yet. The present study combined classical isolation techniques and identification by MALDI-TOF MS with 16S rRNA amplicon sequencing to assess bacterial contamination on broiler carcasses that were either bought fresh and then frozen for short periods (total n = 20) in home freezing, or industrial frozen one (total n = 4) at retail. Changes in total aerobic bacteria (TAB) were also studied on 78 freshly bought broiler carcasses that were then stored frozen for up to 6 months in domestic freezers. Salmonella and Campylobacter were examined to assess the effect of freezing on controlling common foodborne pathogens. The contamination level of mesophilic and psychrotrophic TAB was numerically equal on carcasses at retail, either fresh or frozen at different time points. After short and long freezing period, a decrease in counts of mesophilic TAB was observed, while changes in counts of psychrotrophic TAB were rarely observed. No correlation between home freezing period and TAB load, either mesophilic (R = -0.006, p = 0.949) or psychrotrophic (R = 0.080, p = 0.389), was observed. No Salmonella and Campylobacter was detected on industrial frozen carcasses but on fresh carcasses at retail, either pre-freezing or after freezing. The bacterial communities were influenced by freezing, in which some genera showed significantly changes in relative abundance after freezing. In conclusion, from a food safety point of view, freezing of meat products does not serve as safety hurdle, and freezing should only be considered as a method for extending shelf life compared with fresh chicken meat. Applying hygienic slaughter procedures to keep the initial contamination as low as possible, and the maintenance of the cold chain during further processing are the key factors in food safety.


Asunto(s)
Bacterias/crecimiento & desarrollo , Pollos/microbiología , Microbiología de Alimentos , Conservación de Alimentos , Congelación , Aves de Corral/microbiología , Animales , Bacterias/aislamiento & purificación , Carga Bacteriana , Campylobacter/crecimiento & desarrollo , Campylobacter/aislamiento & purificación , Recuento de Colonia Microbiana , Manipulación de Alimentos , ARN Ribosómico 16S , Salmonella/crecimiento & desarrollo , Salmonella/aislamiento & purificación
9.
Cochrane Database Syst Rev ; 1: CD013198, 2021 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-33448349

RESUMEN

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a chronic respiratory condition characterised by persistent respiratory symptoms and airflow limitation. Acute exacerbations punctuate the natural history of COPD and are associated with increased morbidity and mortality and disease progression. Chronic airflow limitation is caused by a combination of small airways (bronchitis) and parenchymal destruction (emphysema), which can impact day-to-day activities and overall quality of life. In carefully selected patients with COPD, long-term, prophylactic use of antibiotics may reduce bacterial load, inflammation of the airways, and the frequency of exacerbations. OBJECTIVES: To assess effects of different prophylactic antibiotics on exacerbations, quality of life, and serious adverse events in people with COPD in three separate network meta-analyses (NMAs), and to provide rankings of identified antibiotics. SEARCH METHODS: To identify eligible randomised controlled trials (RCTs), we searched the Cochrane Airways Group Specialised Register of trials and clinical trials registries. We conducted the most recent search on 22 January 2020. SELECTION CRITERIA: We included RCTs with a parallel design of at least 12 weeks' duration evaluating long-term administration of antibiotics prophylactically compared with other antibiotics, or placebo, for patients with COPD. DATA COLLECTION AND ANALYSIS: This Cochrane Review collected and updated pair-wise data from two previous Cochrane Reviews. Searches were updated and additional studies included. We conducted three separate network meta-analyses (NMAs) within a Bayesian framework to assess three outcomes: exacerbations, quality of life, and serious adverse events. For quality of life, we collected data from St George's Respiratory Questionnaire (SGRQ). Using previously validated methods, we selected the simplest model that could adequately fit the data for every analysis. We used threshold analysis to indicate which results were robust to potential biases, taking into account each study's contributions to the overall results and network structure. Probability ranking was performed for each antibiotic class for exacerbations, quality of life, and serious adverse events. MAIN RESULTS: Characteristics of studies and participants Eight trials were conducted at multiple sites that included hospital clinics or academic health centres. Seven were single-centre trials conducted in hospital clinics. Two trials did not report settings. Trials durations ranged from 12 to 52 weeks. Most participants had moderate to severe disease. Mean age ranged from 64 years to 73 years, and more males were recruited (51% to 100%). Forced expiratory volume in one second (FEV1) ranged from 0.935 to 1.36 L. Most participants had previous exacerbations. Data from 12 studies were included in the NMAs (3405 participants; 16 treatment arms including placebo). Prophylactic antibiotics evaluated were macrolides (azithromycin and erythromycin), tetracyclines (doxycyclines), quinolones (moxifloxacin) and macrolides plus tetracyclines (roxithromycin plus doxycycline). Risk of bias and threshold analysis Most studies were at low risk across domains, except detection bias, for which only seven studies were judged at low risk. In the threshold analysis for exacerbations, all comparisons in which one antibiotic was compared with another were robust to sampling variation, especially macrolide comparisons. Comparisons of classes with placebo were sensitive to potential bias, especially macrolide versus placebo, therefore, any bias in the comparison was likely to favour the active class, so any adjustment would bring the estimated relative effect closer to the null value, thus quinolone may become the best class to prevent exacerbations. Exacerbations Nine studies were included (2732 participants) in this NMA (exacerbations analysed as time to first exacerbation or people with one or more exacerbations). Macrolides and quinolones reduced exacerbations. Macrolides had a greater effect in reducing exacerbations compared with placebo (macrolides: hazard ratio (HR) 0.67, 95% credible interval (CrI) 0.60 to 0.75; quinolones: HR 0.89, 95% CrI 0.75 to 1.04), resulting in 127 fewer people per 1000 experiencing exacerbations on macrolides. The difference in exacerbations between tetracyclines and placebo was uncertain (HR 1.29, 95% CrI 0.66 to 2.41). Macrolides ranked first (95% CrI first to second), with quinolones ranked second (95% CrI second to third). Tetracyclines ranked fourth, which was lower than placebo (ranked third). Contributing studies were considered as low risk of bias in a threshold analysis. Quality of life (SGRQ) Seven studies were included (2237 participants) in this NMA. SGRQ scores improved with macrolide treatment compared with placebo (fixed effect-fixed class effect: mean difference (MD) -2.30, 95% CrI -3.61 to -0.99), but the mean difference did not reach the minimally clinical important difference (MCID) of 4 points. Tetracyclines and quinolones did not improve quality of life any more than placebo, and we did not detect a difference between antibiotic classes. Serious adverse events Nine studies were included (3180 participants) in the NMA. Macrolides reduced the odds of a serious adverse event compared with placebo (fixed effect-fixed class effect: odds ratio (OR) 0.76, 95% CrI 0.62 to 0.93). There was probably little to no difference in the effect of quinolone compared with placebo or tetracycline plus macrolide compared with placebo. There was probably little to no difference in serious adverse events between quinolones or tetracycline plus macrolide. With macrolide treatment 49 fewer people per 1000 experienced a serious adverse event compared with those given placebo. Macrolides ranked first, followed by quinolones. Tetracycline did not rank better than placebo. Drug resistance Ten studies reported drug resistance. Results were not combined due to variation in outcome measures. All studies concluded that prophylactic antibiotic administration was associated with the development of antimicrobial resistance. AUTHORS' CONCLUSIONS: This NMA evaluated the safety and efficacy of different antibiotics used prophylactically for COPD patients. Compared to placebo, prolonged administration of macrolides (ranked first) appeared beneficial in prolonging the time to next exacerbation, improving quality of life, and reducing serious adverse events. No clear benefits were associated with use of quinolones or tetracyclines. In addition, antibiotic resistance was a concern and could not be thoroughly assessed in this review. Given the trade-off between effectiveness, safety, and risk of antibiotic resistance, prophylactic administration of antibiotics may be best reserved for selected patients, such as those experiencing frequent exacerbations. However, none of the eligible studies excluded patients with previously isolated non-tuberculous mycobacteria, which would contraindicate prophylactic administration of antibiotics, due to the risk of developing resistant non-tuberculous mycobacteria.


Asunto(s)
Antibacterianos/uso terapéutico , Profilaxis Antibiótica/métodos , Carga Bacteriana/efectos de los fármacos , Progresión de la Enfermedad , Metaanálisis en Red , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Adulto , Anciano , Antibacterianos/efectos adversos , Profilaxis Antibiótica/efectos adversos , Teorema de Bayes , Sesgo , Femenino , Volumen Espiratorio Forzado , Humanos , Macrólidos/efectos adversos , Macrólidos/uso terapéutico , Masculino , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica/complicaciones , Enfermedad Pulmonar Obstructiva Crónica/microbiología , Calidad de Vida , Quinolonas/efectos adversos , Quinolonas/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Tetraciclinas/efectos adversos , Tetraciclinas/uso terapéutico , Resultado del Tratamiento
10.
Int J Food Microbiol ; 341: 109069, 2021 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-33508582

RESUMEN

Listeria monocytogenes has caused outbreaks of foodborne illness from apples in the USA, and is also a major issue for regulatory compliance worldwide. Due to apple's significance as an important export product from New Zealand, we aimed to determine the effect of long-term, low-temperature sea-freight from New Zealand to the USA (July) and Europe (March-April), two key New Zealand markets, on the survival and/or growth of L. monocytogenes on fresh apples. Temperature and humidity values were recorded during a shipment to each market (USA and Europe), then the observed variations around the 0.5 °C target temperature were simulated in laboratory trials using open ('Scired') and closed ('Royal Gala' for the USA and 'Cripps Pink' for Europe) calyx cultivars of apples inoculated with a cocktail of 107-108 cells of seven strains of L. monocytogenes. Samples were analysed for L. monocytogenes quantification at various intervals during the simulation and on each occasion, an extra set was analysed after a subsequent 8 days at 20 °C. When both the sea-freight simulations concluded, L. monocytogenes showed 5 log reductions on the equatorial surface of skin of apples, but only about 2.5 log reduction for USA and about 3.3 log reduction for Europe in the calyx. Cultivar type had no significant effect on the survival of L. monocytogenes for both sea-freight simulations, either in the calyx or on the skin (P > 0.05). Most of the reduction in the culturable cells on the skin occurred during the initial 2 weeks of the long-term storage simulations. There was also no significant difference in the reduction of L. monocytogenes at 0.5 or 20 °C. No correlation was observed between firmness or total soluble solids and survival of L. monocytogenes. Because the inoculated bacterial log reduction was lower in the calyx than on the skin, it is speculated that the risk of causing illness is higher if contaminated apple cores are eaten. The result suggested that the international sea-freight transportation does not result in the growth of L. monocytogenes irrespective of time and temperature. The results of this study provide useful insights into the survival of L. monocytogenes on different apple cultivars that can be used to develop effective risk mitigation strategies for fresh apples during long-term, low-temperature international sea-freight transportation.


Asunto(s)
Manipulación de Alimentos/métodos , Listeria monocytogenes/aislamiento & purificación , Malus/microbiología , Refrigeración/métodos , Carga Bacteriana , Frío , Recuento de Colonia Microbiana , Europa (Continente) , Microbiología de Alimentos/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/prevención & control , Nueva Zelanda
11.
Int J Food Microbiol ; 341: 109047, 2021 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-33515813

RESUMEN

Nowadays, adding biological compounds to food packaging is one of the types of active packaging. The aim of this study was to prepare a new degradable coating with free and nano-encapsulated Cumino cyminum L. essential oil (CCEO) with nanochitosan (Nch) base to evaluate the microbial, chemical and sensory properties of sardine fillet samples for 16 days at 4 °C. Nanoliposome using different soy lecithin ratios and cholesterol concentrations (60:0, 50:10, 40:20, and 30:30) and technique of thin-film hydration-sonication, were prepared with a range of 140-164 nm size. Encapsulation efficiency (EE) and distribution of nanoliposomes size were calculated 0.80-0.90 and 49.85-73.01% respectively. To coat sardine fillet samples, nanoliposomes with the lower size of droplet and higher EE percent were selected. The outcomes indicated that coating treatments can effectively inhibit microbial growth and chemical spoilage reflected at lower pH, peroxide value (PV) and thiobarbituric acid reactive substances (TBARs) (P < 0.05). In fact, the results of chemical and microbiological characteristics showed that the samples treated with nanocitosan/nano essential oil (NEO) showed the lowest value among other treatments during the experimental period, in the following, Nch-EO, Nch and control. pH, PV, TBARs, total viable counts (TVC), total pseudomonads count (TPC), and lactic acid bacteria (LAB) were 6.85, 0.03 (mg MDA/kg), 5.23 (mEq/kg), 3.67 (CFU/g), 3.47 (CFU/g), and 4.7 (CFU/g), respectively for Nch-NEO at the end of storage time. In addition, during the experimental period, the highest sensory properties were obtained for the Nch-NEO group. Encapsulation of CCEO reduces the rate of diffusion, thus increasing antimicrobial and antioxidant activity, as well as improving sensory properties. According to the results of this study, CCEO-encapsulated nanochitosan coatings can be used as a potent coating to increase sardine shelf life.


Asunto(s)
Antibacterianos/farmacología , Quitosano/farmacología , Cuminum/química , Embalaje de Alimentos/métodos , Aceites Volátiles/farmacología , Alimentos Marinos/microbiología , Animales , Antioxidantes/química , Antioxidantes/farmacología , Carga Bacteriana/efectos de los fármacos , Quitosano/química , Colesterol/farmacología , Peces/microbiología , Conservación de Alimentos/métodos , Almacenamiento de Alimentos/métodos , Lecitinas/farmacología
12.
Food Chem ; 340: 127922, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-32889211

RESUMEN

This study aimed to evaluate the fermentation performance of a mixture of Lactobacillus spp. in cloudy apple juices from nine cultivars. The results showed that cultivar influenced most the properties of the fermented cloudy apple juice. The fermented cloudy apple juices made from Changfu had the highest viable bacterial count and acetic acid contents (6.37 × 108 CFU/mL and 2.67 mg/mL, respectively). It also had higher sensory score, second only to Huaniu. The highest total sugar consumption, utilising fructose, glucose, and sucrose (33.07 mg/mL), was seen with Golden Delicious. Qinguan fermented cloudy apple juice had the highest contents of lactic acid (6.74 mg/mL) and total esters (921.36 µg/L); d-limonene also detected in this fermented cloudy apple juice. Of the nine cultivars examined in this study, Changfu, Qinguan, and Golden Delicious were the most suitable for producing fermented cloudy apple juice with better taste, higher viable count and more intense aroma.


Asunto(s)
Alimentos y Bebidas Fermentados/microbiología , Jugos de Frutas y Vegetales/análisis , Jugos de Frutas y Vegetales/microbiología , Malus , Ácido Acético/análisis , Carga Bacteriana , Femenino , Fermentación , Alimentos y Bebidas Fermentados/análisis , Humanos , Lactobacillus acidophilus , Lactobacillus fermentum , Lactobacillus plantarum , Masculino , Odorantes/análisis , Azúcares/análisis , Gusto , Compuestos Orgánicos Volátiles/análisis
13.
J Exp Med ; 218(2)2021 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-33180929

RESUMEN

Typhoid Vi vaccines have been shown to be efficacious in children living in endemic regions; however, a widely accepted correlate of protection remains to be established. We applied a systems serology approach to identify Vi-specific serological correlates of protection using samples obtained from participants enrolled in an experimental controlled human infection study. Participants were vaccinated with Vi-tetanus toxoid conjugate (Vi-TT) or unconjugated Vi-polysaccharide (Vi-PS) vaccines and were subsequently challenged with Salmonella Typhi bacteria. Multivariate analyses identified distinct protective signatures for Vi-TT and Vi-PS vaccines in addition to shared features that predicted protection across both groups. Vi IgA quantity and avidity correlated with protection from S. Typhi infection, whereas higher fold increases in Vi IgG responses were associated with reduced disease severity. Targeted antibody-mediated functional responses, particularly neutrophil phagocytosis, were also identified as important components of the protective signature. These humoral markers could be used to evaluate and develop efficacious Vi-conjugate vaccines and assist with accelerating vaccine availability to typhoid-endemic regions.


Asunto(s)
Fiebre Tifoidea/inmunología , Vacunas Tifoides-Paratifoides/inmunología , Vacunas Conjugadas/inmunología , Adulto , Carga Bacteriana , Humanos , Inmunidad Humoral , Inmunogenicidad Vacunal , Inmunoglobulina G/sangre , Factores de Tiempo , Fiebre Tifoidea/prevención & control , Vacunas Tifoides-Paratifoides/farmacología , Vacunas Conjugadas/farmacología
14.
Methods Mol Biol ; 2248: 211-220, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33185878

RESUMEN

Tuberculosis of the central nervous system (CNS-TB) is the most severe form of extra-pulmonary tuberculosis that is often associated with high mortality. Secretion of tumor necrosis factor (TNF) has important protective and immune modulatory functions for immune responses during CNS-TB. Therefore, by combining the approaches of aerosol and intracerebral infection in mice, this chapter describes the methods to investigate the contribution of TNF in protective immunity against CNS-TB infection.


Asunto(s)
Mycobacterium tuberculosis , Tuberculosis del Sistema Nervioso Central/metabolismo , Tuberculosis del Sistema Nervioso Central/microbiología , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Carga Bacteriana , Biomarcadores , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Citometría de Flujo , Interacciones Huésped-Patógeno , Inmunohistoquímica , Ratones , Microscopía Confocal , Mycobacterium tuberculosis/inmunología , Tuberculosis del Sistema Nervioso Central/tratamiento farmacológico , Tuberculosis del Sistema Nervioso Central/inmunología
15.
Methods Mol Biol ; 2220: 189-200, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32975776

RESUMEN

Listeria monocytogenes is a model intracellular pathogen that can invade the cytoplasm of host mammalian cells. Cellular invasion can be measured using standard techniques, such as the classical gentamicin protection assay, based on the quantification of colony-forming units from lysates of infected cells. In addition, there are methods based on immunofluorescence microscopy which allow for assaying invasion in a medium- to high-throughput manner. In the following sections, we detail two different assays that can be used alone or in combination to quantify the internalization of L. monocytogenes in host cells.


Asunto(s)
Listeria monocytogenes/fisiología , Listeriosis/patología , Carga Bacteriana/métodos , Recuento de Colonia Microbiana/métodos , Células HeLa , Interacciones Huésped-Patógeno , Humanos , Listeriosis/microbiología , Coloración y Etiquetado/métodos
16.
Methods Mol Biol ; 2220: 219-231, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32975778

RESUMEN

Biofilm-forming ability may vary significantly among different Listeria (L.) monocytogenes strains. This interstrain variation is also observed in L. monocytogenes biofilm resistance to antimicrobial compounds commonly used in the food-processing environment. The screening of a large set of L. monocytogenes strains with specific characteristics, such as serotype, MLST type, and other genetic characteristics under various environmental conditions, may lead to a better understanding of the mechanisms underlying the establishment of the pathogen on food contact surfaces. In this chapter, traditional methods for L. monocytogenes strains characterization with regard to biofilm formation and novel biofilm control methods will be described.


Asunto(s)
Biopelículas , Manipulación de Alimentos , Microbiología de Alimentos , Listeria monocytogenes/aislamiento & purificación , Listeria monocytogenes/fisiología , Carga Bacteriana/métodos , Desinfección/métodos , Manipulación de Alimentos/métodos , Humanos , Listeriosis/microbiología , Microscopía Fluorescente/métodos , Propiedades de Superficie
17.
Diving Hyperb Med ; 50(4): 332-337, 2020 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-33325012

RESUMEN

INTRODUCTION: Healthcare acquired infections (HAIs) are associated with increased mortality, morbidity and prolonged hospital stays. Microbiological contamination of the hospital environment directly contributes to HAIs. Optimising environmental cleaning reduces transmission of HAIs. The hyperbaric chamber poses a specific challenge for infection control as certain disinfectants and alcohol-based hand sanitisers are prohibited due to fire risk. Patients often possess multiple risk factors for HAIs. This study compared the bacteria remaining on a surface (bioburden) after a standard clean and after adjunctive disinfection with an ultraviolet-C (UV-C) robot. METHODS: Internal hyperbaric chamber surfaces were first manually cleaned with Clinell® universal wipes and the floor was mopped with Whiteley neutral detergent. Allocated surfaces were swabbed using sterile cotton swabs and processed using a standard microbial culture and a bacteria-specific rapid metabolic assay. Bacterial contamination was also measured by direct contact plating on flat surfaces. The plexiglass ports were covered to protect from potential UV-C mediated damage and used as a negative control. A UV-C disinfection robot was then used to disinfect the chamber for 30 min, whereafter surfaces were swabbed again. RESULTS: There was a significantly greater mean reduction in bioburden following adjunctive UV-C disinfection than with standard cleaning alone. The surfaces not routinely manually cleaned (e.g., bench, phone) showed greatest reduction in bacterial load following UV-C cleaning. CONCLUSIONS: There was a significant reduction in the bacterial load in the chamber following an adjunctive UV-C clean compared with that of a standard clean. Adjunctive cleaning of the hyperbaric chamber environment with a non-touch UV-C device shows promise as a method to reduce HAIs.


Asunto(s)
Infección Hospitalaria , Desinfección , Bacterias , Carga Bacteriana , Infección Hospitalaria/prevención & control , Hospitales , Humanos
18.
PLoS One ; 15(10): e0239587, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33006973

RESUMEN

Resource-deprived coastal peri-urban settlements in Southern Ghana are characterized by indiscriminate solid waste disposal and open defecation practices. Persons engaged in waste handling in such communities perform their activities with little or no personal protective equipment. They are thus confronted with the risk of faecal pollution of the hands and other bodily parts. A mixed method approach was used to investigate 280 waste handlers performing different activities to estimate recent faecal pollution of their hands and to observe the utilization of personal protective equipment and sanitation/hygiene facilities during work. The log concentration of E. coli on hands of waste handlers after work (8.60 ± 4.20 CFU/hand, mean ± standard deviation) was significantly higher compared with the E. coli log concentration before work (2.95 ± 1.89 CFU/hand, mean ± standard deviation) (p<0.001). The odds of faecal pollution was significantly higher (aOR 4.2; 95% CI: 1.9-9.1) for workers aged 35 years and above compared with those less than 35 years; and for workers at public toilet facilities (aOR 3.0; 95% CI: 1.0-8.4) compared with those who worked for private waste handling companies. Female workers were, however, 60% less likely (aOR 0.4; 95% CI: 0.2-0.8) to experience faecal pollution of their hands compared with males. The workers had limited access to water and sanitation and hygiene facilities, and about one-fifth (n = 59; 21.1%) did not use personal protective equipment during work. Waste handlers should be provided and instructed in proper use of personal protective equipment, have access to sanitation facilities and adopt improved hygiene behaviour to avoid the risk of faecal pollution and associated disease risk.


Asunto(s)
Heces , Exposición Profesional , Eliminación de Residuos , Adulto , Carga Bacteriana , Defecación , Contaminación Ambiental/prevención & control , Escherichia coli/aislamiento & purificación , Heces/microbiología , Femenino , Ghana , Mano/microbiología , Humanos , Masculino , Persona de Mediana Edad , Exposición Profesional/prevención & control , Factores de Riesgo , Cuartos de Baño , Población Urbana
19.
PLoS One ; 15(9): e0239668, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32970762

RESUMEN

We developed an approach for substantial attenuation of Mycobacterium tuberculosis by prolonged culturing under gradually acidifying conditions. Bacteria subjected to acidification lost the capacity to form colonies on solid media, but readily resuscitated their growth in the murine host, providing a useful model to study in vivo development of infection mimicking latent and reactivation tuberculosis (TB) in humans. Here we characterize biomarkers of lung pathology and immune responses triggered by such attenuated bacteria in genetically TB-susceptible and resistant mice. In susceptible I/St mice, CFU counts in lungs and spleens were ~1.5-log higher than in resistant B6 mice, accompanied by diffuse pneumonia and excessive lung infiltration with highly activated CD44+CD62L- T-lymphocytes resulting in death between months 7-9 post challenge. B6 mice were characterized by development of local inflammatory foci, higher production of pro-inflammatory IL-6 and IL-11 cytokines and a more balanced T-cell activation in their lungs. CFU counts remained stable in B6 mice during the whole 18-mo observation period, and all mice survived. Thus, we established a mouse model of fatal reactivation TB vs. indefinite mycobacterial possession after identical challenge and characterized the features of immune responses in the lung tissue underlining these polar phenotypes.


Asunto(s)
Predisposición Genética a la Enfermedad , Interleucinas/metabolismo , Pulmón/inmunología , Activación de Linfocitos , Tuberculosis Pulmonar/inmunología , Tuberculosis Esplénica/inmunología , Animales , Carga Bacteriana , Células Cultivadas , Femenino , Receptores de Hialuranos/genética , Receptores de Hialuranos/metabolismo , Interleucinas/genética , Selectina L/genética , Selectina L/metabolismo , Pulmón/microbiología , Ratones , Ratones Endogámicos C57BL , Mycobacterium tuberculosis/patogenicidad , Bazo/inmunología , Bazo/microbiología , Linfocitos T/inmunología , Tuberculosis Pulmonar/genética , Tuberculosis Esplénica/genética
20.
Int J Hematol ; 112(6): 851-859, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32880823

RESUMEN

The aim of this study is to investigate the association between chemotherapy-induced fever with neutropenia less than 1500/µL (FwN) and oral bacteria and/or oral immunity in patients with hematological cancer. Thirty-two patients with hematological cancer were enrolled in the study. Secretory immunoglobulin A (sIgA) in saliva and the anaerobic bacteria in tongue coating of each subject were assessed before the first chemotherapy. Eleven subjects had an onset of FwN and 21 subjects did not during the observation periods. It was revealed by the Cox-proportional hazard model analysis that the levels of sIgA were low (HR 0.98, p < 0.05) and the rate of Fusobacterium nucleatum [F. nucleatum count per total bacterial count (%)] was high (HR 1.65, p < 0.05) in patients with FwN onset. Using ROC curve analysis, the optimal cutoff point based on the AUC in the F. nucleatum/sIgA ratio was 0.023, and this model had a 78.4% probability (p < 0.01). The risk of FwN onset was also significantly higher among the group of ≥ 0.023 F. nucleatum/sIgA ratio (HR 66.06, p < 0.01). These results suggest that the rate of F. nucleatum and the levels of sIgA at baseline might be related to FwN onset as risk factors.


Asunto(s)
Antineoplásicos/efectos adversos , Neutropenia Febril/etiología , Neoplasias Hematológicas/tratamiento farmacológico , Neoplasias Hematológicas/inmunología , Inmunoglobulina A Secretora , Boca/inmunología , Boca/microbiología , Adulto , Anciano , Anciano de 80 o más Años , Carga Bacteriana , Femenino , Fusobacterium nucleatum/aislamiento & purificación , Neoplasias Hematológicas/complicaciones , Neoplasias Hematológicas/microbiología , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Adulto Joven
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