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1.
J Med Microbiol ; 69(1): 120-131, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31916929

RESUMEN

Introduction. Staphylococcus aureus biofilms are difficult to treat and the effect of telithromycin treatment is still unclear.Aim. This study aimed to explore the effect of telithromycin against Staphylococcus aureus biofilms compared with azithromycin, clindamycin, vancomycin and daptomycin.Methodology. Eight methicillin-susceptible and eight methicillin-resistant S. aureus isolates (MSSA and MRSA, respectively) were used for this study. Biofilm biomasses were detected by crystal violet staining and the adherent cells in the established biofilms were quantified by determination of colony-forming units (c.f.u.). The RNA levels of biofilm formation-related genes were determined by RT-qPCR.Results. Telithromycin [8× minimum inhibitory concentration (MIC)] eradicated more established biofilms than azithromycin or clindamycin in the four MSSA isolates, and eliminated the established biofilms of six MRSA isolates more effectively than vancomycin or daptomycin. Telithromycin (8× MIC) killed more adherent cells in the established biofilms than azithromycin or clindamycin in the six MSSA isolates, and killed more adherent cells than vancomycin in all eight MRSA isolates. Daptomycin also showed an excellent effect on the adherent cells of MRSA isolates, with similarresults to telithromycin. The effect of a subinhibitory concentration of telithromycin (1/4× MIC) was significantly superior to that of azithromycin or clindamycin, inhibiting the biofilm formation of six MSSA isolates and seven MRSA isolates more effectively than vancomycin or daptomycin. The RNA levels of agrA, agrC, clfA, icaA and sigB decreased when treated with telithromycin (1/4× MIC).Conclusions. Telithromycin is more effective than azithromycin, clindamycin, vancomycin, or daptomycin against S. aureus biofilms.


Asunto(s)
Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Cetólidos/farmacología , Staphylococcus aureus/efectos de los fármacos , Recuento de Colonia Microbiana , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , ARN Bacteriano/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
2.
World J Microbiol Biotechnol ; 36(2): 24, 2020 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-31965331

RESUMEN

The study evaluated the antibacterial activity of chlorogenic acid (CA) against Salmonella Enteritidis S1, a foodborne pathogen in chilled fresh chicken. Its minimum inhibitory concentration for S. Enteritidis S1 was 2 mM. 1 MIC CA treatment reduced the viable count of S. Enteritidis S1 by 3 log cfu/g in chilled fresh chicken. Scanning electron microscopy examination indicated that CA induced the cell envelope damage of S. Enteritidis S1. Following this, 1-N-Phenylnaphthylamine assay and LPS content analysis indicated that CA induced the permeability of outer membrane (OM). Confocal laser scanning microscopy examination further demonstrated that CA acted on the inner membrane (IM). To support this, the release of intracellular protein and ATP after CA treatment was also observed. CA also suppressed the activities of malate dehydrogenase and succinate dehydrogenase, two main metabolic enzymes in TCA cycle and electron transport chain. Thus, damage of intracelluar and outer membranes as well as disruption of cell metabolism resulted in cell death eventually. The finding suggested that CA has the potential to be developed as a preservative to control S. Enteritidis associated foodborne diseases.


Asunto(s)
Antibacterianos/farmacología , Ácido Clorogénico/farmacología , Salmonella enteritidis/efectos de los fármacos , Animales , Proteínas Bacterianas/antagonistas & inhibidores , Membrana Celular/efectos de los fármacos , Pollos/microbiología , Recuento de Colonia Microbiana , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Malato Deshidrogenasa/antagonistas & inhibidores , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , Microscopía Electrónica de Rastreo , Salmonella enteritidis/enzimología , Salmonella enteritidis/crecimiento & desarrollo , Succinato Deshidrogenasa/antagonistas & inhibidores
3.
J Appl Oral Sci ; 28: e20190100, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31800872

RESUMEN

OBJECTIVE: This clinical study sought to evaluate the effectiveness of passive ultrasonic activation (PUA) in eliminating microorganisms in primary endodontic infection (PEI) after instrumentation of root canals using microbiological culture and checkerboard DNA-DNA hybridization. METHODOLOGY: Twenty root canals with PEI and apical periodontitis were selected. The root canals were instrumented and then randomly divided into 2 groups, according to the irrigation method: PUA and conventional needle irrigation (CNI). Microbiological samples were collected before instrumentation (S1), after instrumentation (S2) and after irrigation with 17% EDTA (S3). The samples were subjected to anaerobic culture technique and checkerboard DNA-DNA hybridization analysis. RESULTS: A statistically significant difference was found between CNI (23.56%) and PUA (98.37%) regarding the median percentage values for culturable bacteria reduction (p<0.05). In the initial samples, the most frequently detected species was S. constellatus (50%), and after root canal treatment was E. faecalis (50%). CONCLUSION: Both treatments significantly decreased the number of bacterial species compared with the initial sample. However, no statistical difference in the total microbial load between PUA and CNI groups was detected. The number of cultivable anaerobic bacteria reduced significantly using PUA, and the bacterial composition and number of bacterial species after using either CNI or PUA was similar.


Asunto(s)
Cavidad Pulpar/microbiología , Periodontitis Periapical/terapia , Tratamiento del Conducto Radicular/instrumentación , Terapia por Ultrasonido/instrumentación , Adolescente , Adulto , Análisis de Varianza , Bacterias/aislamiento & purificación , Carga Bacteriana , Recuento de Colonia Microbiana , Tomografía Computarizada de Haz Cónico , Sondas de ADN , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Irrigantes del Conducto Radicular/uso terapéutico , Tratamiento del Conducto Radicular/métodos , Hipoclorito de Sodio/uso terapéutico , Irrigación Terapéutica/instrumentación , Irrigación Terapéutica/métodos , Resultado del Tratamiento , Terapia por Ultrasonido/métodos , Adulto Joven
4.
Int J Food Microbiol ; 312: 108387, 2020 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-31669763

RESUMEN

Fresh produce-associated outbreaks of foodborne illnesses continue to occur every year in the U.S., suggesting limitations of current practices and the need for effective intervention technologies. Advanced oxidation process involves production of hydrogen radicals, which are the strongest oxidant. The objective of the present study was to evaluate the effectiveness of advanced oxidation process by combining gaseous ozone and aerosolized hydrogen peroxide. Grape tomatoes were inoculated with a 2-strain cocktail of Salmonella typhimurium on both stem scar and smooth surface. Gaseous ozone (800 and 1600 ppm) and aerosolized hydrogen peroxide (2.5, 5 and 10%) were separately or simultaneously introduced into a treatment chamber where the inoculated tomatoes were placed. During the 30 min treatments, hydrogen peroxide was aerosolized using an atomizer operated in two modes: continuously or 15 s on/50 s off. After the treatments, surviving Salmonella on the smooth surface and stem scar were enumerated. Results showed that ozone alone reduced Salmonella populations by <0.6 log CFU/fruit on both the smooth surface and the stem scar area, and aerosolized hydrogen peroxide alone reduced the populations by up to 2.1 log CFU/fruit on the smooth surface and 0.8 log CFU/fruit on stem scar area. However, the combination treatments reduced the populations by up to 5.2 log CFU/fruit on smooth surface and 4.2 log CFU/fruit on the stem scar. Overall, our results demonstrate that gaseous ozone and aerosolized hydrogen peroxide have synergistic effects on the reduction of Salmonella populations on tomatoes.


Asunto(s)
Enfermedades Transmitidas por los Alimentos/prevención & control , Peróxido de Hidrógeno/farmacología , Lycopersicon esculentum/microbiología , Ozono/farmacología , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/crecimiento & desarrollo , Recuento de Colonia Microbiana , Microbiología de Alimentos/métodos , Frutas/microbiología , Oxidación-Reducción
5.
Food Microbiol ; 85: 103306, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500703

RESUMEN

Spray dried egg white powder (EWP) is traditionally processed by hot room treatment for a prolonged period of time (67 °C for 15 days) to enhance its functionality (foaming and gelling) and to improve microbial safety of EWP. Our prior research demonstrated that radio-frequency (RF) assisted thermal processing can considerably reduce the processing time, without compromising the functional properties of EWP. In this study, continuous RF processing was evaluated for pasteurization of EWP. EWP samples were inoculated with a 5-strain Salmonella cocktail or Enterococcus faecium NRRL B-2354 for the microbial challenge studies. To evaluate the inoculation method, stability and homogeneity tests were conducted for both Salmonella and E. faecium in EWP. Continuous RF heating of EWP was conducted in a 6-kW, 27.12 MHz pilot-scale parallel-plate RF heating system. RF-assisted thermal processing of EWP at 80 °C for 2 h provided >6.69 log reduction for Salmonella. E. faecium was found to be a suitable surrogate for Salmonella due to its higher resistance and similar inactivation kinetics during RF heating of EWP. The validated RF-assisted thermal process can be scaled up for use in the egg industry.


Asunto(s)
Clara de Huevo/microbiología , Microbiología de Alimentos/métodos , Análisis de Peligros y Puntos de Control Críticos/métodos , Calor , Pasteurización/métodos , Ondas de Radio , Recuento de Colonia Microbiana , Polvos/análisis , Salmonella
6.
Food Microbiol ; 85: 103285, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500704

RESUMEN

The objective of this study was to determine the kinetic parameters and apply Markov Chain Monte Carlo (MCMC) simulation to predict the growth of Clostridium perfringens from spores in cooked ground chicken meat during dynamic cooling. Inoculated samples were exposed to various cooling conditions to observe dynamic growth. A combination of 4 cooling profiles was used in one-step inverse analysis with the Baranyi model as the primary model and the cardinal parameters model as the secondary model. Six kinetic parameters of the Baranyi model and the cardinal parameters model, including Q0, Ymax, µopt, Tmin, Topt, and Tmax, were estimated. The estimated Tmin, Topt, and Tmax were 14.8, 42.9, and 50.5 °C, respectively, with a µopt of 5.25 h-1 and maximum cell density of 8.4 log CFU/g. Correlation analysis showed that both Q0 and Ymax are weakly correlated to other parameters, while the remaining parameters are mostly mildly to strongly correlated with each other. Although it may be difficult to estimate highly correlated parameters using a single temperature profile, one-step analysis with multiple different temperature profiles helped estimate them successfully. The estimated parameters were used as the prior information to construct the posterior distribution for Bayesian analysis. MCMC simulation was used to predict the bacterial growth using different dynamic temperature profiles for validation of the accuracy of the predictive models. The MCMC simulation results showed that the Bayesian analysis produced more accurate predictions of bacterial growth during cooling than the deterministic method. With Bayesian analysis, the root-mean-square-error (RMSE) of prediction was only 0.1 log CFU/g with all residual errors within ±0.25 log CFU/g. Therefore, Bayesian analysis is recommended for predicting the growth of C. perfringens in cooked meat during cooling.


Asunto(s)
Clostridium perfringens/crecimiento & desarrollo , Culinaria , Manipulación de Alimentos , Productos de la Carne/microbiología , Temperatura Ambiental , Animales , Teorema de Bayes , Pollos , Recuento de Colonia Microbiana , Simulación por Computador , Cinética , Cadenas de Markov , Modelos Biológicos , Método de Montecarlo , Esporas Bacterianas/crecimiento & desarrollo
7.
Food Microbiol ; 85: 103280, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500706

RESUMEN

Listeria monocytogenes causes severe diseases in humans, including febrile gastroenteritis and systemic infections that has a high mortality despite antibiotic treatment. This pathogen may cause massive outbreaks associated to the consumption of contaminated food products, which highlight its importance in public health. In the last decade, L. monocytogenes has emerged as a foodborne pathogen of major importance in Chile. A previous work showed that in Chile during 2008 and 2009, L. monocytogenes serotypes 1/2a, 1/2b and 4b were the most frequently identified in food and clinical strains. Here we report the molecular characterization of L. monocytogenes strains isolated from 2008 to 2017 in the country. Our results indicate that serotypes 1/2a, 1/2b and 4b continue to be the most commonly found in food products. In addition, we identify persistent and widespread PFGE subtypes. This study reports ten years of epidemiological surveillance ofL. monocytogenes in Chile.


Asunto(s)
Monitoreo Epidemiológico , Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos/epidemiología , Listeria monocytogenes/genética , Listeriosis/epidemiología , Chile/epidemiología , Recuento de Colonia Microbiana , ADN Bacteriano/genética , Brotes de Enfermedades , Enfermedades Transmitidas por los Alimentos/microbiología , Gastroenteritis/epidemiología , Gastroenteritis/microbiología , Variación Genética , Humanos , Listeria monocytogenes/patogenicidad , Productos de la Carne/microbiología , Epidemiología Molecular , Salud Pública , Serogrupo , Serotipificación , Factores de Virulencia/genética
8.
Food Microbiol ; 85: 103302, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500708

RESUMEN

This study dealt with the influence of the temperature on the bacterial dynamics of two spontaneously fermented wheat sourdoughs, propagated at 21 ±â€¯1 °C (SD1) and 30 ±â€¯1 °C (SD2), during nine backslopping steps (BS1 to BS9). Proteobacteria was the only phylum found in flour. Escherichia hermannii was predominant, followed by Kosakonia cowanii, besides species belonging to the genera Pantoea and Pseudomonas. After one step of propagation, Clostridium and Bacillus cereus group became predominant. Lactobacillus curvatus was found at low relative abundance. For the second backslopping step, Clostridium was flanked by L. curvatus and Lactobacillus farciminis. From BS4 (6th day) onward, lactic acid bacteria (LAB) became predominant. L. farciminis overcame L. curvatus and remained dominant until the end of propagations for both sourdoughs. At 21 °C, Bacillus, Clostridium, Pseudomonas, and Enterobacteriaceae were gradually inhibited. At the end of propagation, SD1 harbored only LAB. Otherwise, the temperature of 30 °C favored the persistence of atypical bacteria in SD2, as Pseudomonas and Enterobacteriaceae. Therefore, the temperature of 21 °C was more suitable for sourdough propagation in Brazil. This study enhanced the knowledge of temperature's influence on microbial assembly and contributed to the elucidation of sourdough microbial communities in Brazil.


Asunto(s)
Pan/microbiología , Fermentación , Metagenoma , Proteobacteria/clasificación , Brasil , Recuento de Colonia Microbiana , ADN Bacteriano/genética , Harina/microbiología , Variación Genética , Secuenciación de Nucleótidos de Alto Rendimiento , Microbiota , Proteobacteria/crecimiento & desarrollo , ARN Ribosómico 16S/genética , Temperatura Ambiental
9.
Food Microbiol ; 85: 103286, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500709

RESUMEN

Hispanic style soft non-fermented cheeses, such as queso fresco (QF) have been linked to outbreaks and recalls. Salmonella is one of the main causes of these incidents. Due to lack of ripening or post-processing antimicrobial treatments, incorporating GRAS antimicrobials to production process may be a suitable approach to minimize microbial risk in QF. The aim of this study was to evaluate the efficiency of nisin (N), caprylic acid (CA) and trans-cinnamaldehyde (CN) as single or combined treatments to reduce Salmonella populations in QF during storage. Batches of QF were inoculated after curding with approx. 4 Log CFU/g of 5-strain cocktails of Salmonella and stored at 8 °C for 20 days. The final Salmonella counts in control samples ranged from 6.96 to 7.14 Log CFU/g. Application of CN at 0.6 g/kg inhibited Salmonella growth during storage, resulting in at least 3 Log CFU/g difference with the untreated controls (p < 0.05). Addition of N (0.5 g/kg) and CA (0.4 g/kg) with CN (0.3 and 0.6 g/kg) further enhanced the antimicrobial activity resulting in complete suppression of growth and even caused a 1 Log CFU/g reduction by the end of the experimental period compared to initial counts. Samples treated with the combined treatment (N, CA, CN) were evaluated in a consumer panel (n = 112). Participants preferred the control and commercial QF to the treated samples. However, treated samples with 0.3 g/kg CN were still within the acceptable range of neutral to like slightly. Results obtained, revealed that combined treatment of N, CA and CN can provide a solution to reduce the count of Salmonella in QF, whether in process or during storage.


Asunto(s)
Antibacterianos/farmacología , Queso/microbiología , Microbiología de Alimentos/métodos , Viabilidad Microbiana/efectos de los fármacos , Salmonella/efectos de los fármacos , Caprilatos/farmacología , Recuento de Colonia Microbiana , Manipulación de Alimentos , Conservación de Alimentos , Nisina/farmacología
10.
Food Microbiol ; 85: 103274, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500714

RESUMEN

The impact of plant development, environmental conditions at the time of inoculation, and inoculum concentration on survival of attenuated BSL1 Escherichia coli O157:H7 strain ATCC 700728 on field-grown romaine lettuce was evaluated over 3 years. E. coli 700728 was inoculated onto 4- and 6-week-old romaine lettuce plants in the Salinas Valley, CA, at night or the next morning with either low (5 log) or high (7 log) cell numbers per plant to simulate a single aqueous contamination event. At night, when leaf wetness and humidity levels were high, E. coli cell numbers declined by 0.5 log CFU/plant over the first 8-10 h. When applied in the morning, E. coli populations declined up to 2 log CFU/plant within 2 h. However, similar numbers of E. coli were retrieved from lettuce plants at 2 and 7 days. E. coli cell numbers per plant were significantly lower (P < 0.05) 7 days after application onto 4-week-old compared to 6-week-old plants. E. coli 700728 could be recovered by plating or enrichment from a greater proportion of plants for longer times when inoculated at high compared with low initial concentrations and after inoculation of 6-week-old plants compared with 4-week-old plants, even at the low initial inoculum. A contamination event near harvest or when leaf wetness and humidity levels are high may enhance survivability, even when low numbers of E. coli are introduced.


Asunto(s)
Escherichia coli O157/crecimiento & desarrollo , Lechuga/microbiología , Viabilidad Microbiana , Hojas de la Planta/microbiología , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Microbiología de Alimentos , Humedad , Factores de Tiempo
11.
Food Microbiol ; 85: 103283, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500718

RESUMEN

Many countries use Escherichia coli and coliforms as indicators of sanitary quality of foods and have set limits for cheeses, including raw-milk cheeses. This paper reviewed the scientific literature for E. coli and coliform levels that are found in different types of raw milk, the fate of indicators during the manufacturing and ripening of different cheeses and the indicator levels that have been found in the finished cheeses. These studies from worldwide showed that E. coli and coliforms are found in different types of raw milk but usually at <100 CFU/ml or not found. Instances where raw milk contained indicator levels >1000 CFU/ml have mostly been attributed to unsanitary conditions/production. During cheese-making, indicators present in raw milk will often increase in numbers, but the levels decline as the acidity from lactose fermentation decreases the pH. Except for fresh cheeses that are not aged, indicator levels are further reduced by 2-3 log10 CFU/g or more, during the ripening process. As a result, indicator levels in finished cheeses are often low and within the limits of <10 or <100 CFU/g set by many countries. The cited studies also show that raw milk cheeses that are made with quality raw milk, under hygienic conditions and properly aged, should not contain high levels of indicator bacteria in the final product.


Asunto(s)
Bacterias/crecimiento & desarrollo , Queso/microbiología , Microbiología de Alimentos/métodos , Microbiología de Alimentos/normas , Alimentos Crudos/microbiología , Animales , Queso/normas , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Escherichia coli/crecimiento & desarrollo , Contaminación de Alimentos/análisis , Manipulación de Alimentos , Leche/microbiología
12.
Int J Food Microbiol ; 313: 108381, 2020 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-31670167

RESUMEN

As a raw agricultural commodity, wheat is exposed to microbial contamination; therefore, enteric pathogens may be among its microbiota creating a food safety risk in milled products. This research evaluates (1) the effectiveness of organic acids dissolved in saline solutions to reduce the counts of pathogenic microorganisms in soft and hard wheat, and also investigates the effect of seasonal temperature on (2) survivability of pathogens in wheat kernels and on (3) pathogen inactivation during tempering with saline organic acid solutions. Wheat samples were inoculated with cocktails of either 5 serovars of Salmonella enterica, 5 E. coli O157:H7 or 6 non-O157 Shiga toxin-producing E. coli (STEC) strains to achieve a concentration of ~7 log CFU/g. Inoculated samples were allowed to stand for 7-days at temperatures (2.0, 10.8, 24.2, 32 °C) corresponding to those experienced during winter, spring/fall, and summer (average and maximum) in the main wheat growing regions in the state of Nebraska, USA. Besides water, solutions containing acid (acetic or lactic 2.5% or 5.0% v/v) and NaCl (~26% w/v) were used for tempering the wheat to 15.0% (soft) and 15.5% (hard) moisture at the different seasonal temperatures. The survival of pathogenic microorganisms throughout the resting period, and before and after tempering was analyzed by plating samples on injury-recovery media. The survival rate of pathogenic microorganisms on wheat kernels was higher at temperatures experienced during the winter (2.0 °C) and spring/fall (10.8 °C) months. Regardless of tempering temperature, the initial pathogen load was reduced significantly by all solutions when compared to the control tempered with water (P ≤ .05). The combination of lactic acid (5.0%) and NaCl was the most effective treatment against Salmonella enterica, E. coli O157:H7 and non-O157 STEC, with average reduction values of 1.8, 1.8 and 1.6 log CFU/g for soft wheat and 2.6, 2.4 and 2.4 log CFU/g for hard wheat, respectively. Implementation of organic acids and NaCl in tempering water may have the potential to reduce the risk of pathogen contamination in milled products.


Asunto(s)
Ácidos/farmacología , Manipulación de Alimentos/métodos , Cloruro de Sodio/farmacología , Triticum/microbiología , Ácidos/química , Recuento de Colonia Microbiana , Escherichia coli O157/efectos de los fármacos , Escherichia coli O157/crecimiento & desarrollo , Manipulación de Alimentos/instrumentación , Microbiología de Alimentos , Inocuidad de los Alimentos , Salmonella enterica/efectos de los fármacos , Salmonella enterica/crecimiento & desarrollo , Estaciones del Año , Temperatura Ambiental
13.
Int J Food Microbiol ; 313: 108378, 2020 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-31678817

RESUMEN

Vibrio bacteria can accumulate in molluscan shellfish and cause human diseases. The United States (U.S.) has implemented Vibrio Control Plans to mitigate risks associated with these bacteria, which include time and temperature requirements for post-harvest processing and maintaining an unbroken cold chain. In this study, we tracked the performance of cold chains for U.S. farmed oysters distributed nationally and internationally using temperature sensors. Boxes and bags of oysters (n = 125) were shipped from farms in Washington State and the Chesapeake Bay to 143 unique businesses in 20 U.S. states, Washington D.C., and Hong Kong, China. Eighty-one percent of the temperature sensors were returned with usable data. The average product temperature among all participants was 4.4 ±â€¯2.7 °C (40 ±â€¯5 °F), which is 5.6 °C (10 °F) cooler than the 10 °C (50 °F) guidance criterium established by the U.S. government. There were spikes in temperature in some shipments: 18% of shipments (16/91) experienced oyster temperatures above 10 °C for one hour or more, and the median time spent out of temperature control was 2.5 h. We modeled V. parahaemolyticus abundance using temperature sensor data and 75% (68/91) of shipments had a net decrease in V. parahaemolyticus abundance in the cold chain. There are opportunities for improvements in cold chain performance in the shellfish industry and related businesses. In the discussion we provide recommendations for oyster producers related to product cooling, for businesses that handle shellfish, and for government and industry groups to develop guidance for shipping by air, among other issues.


Asunto(s)
Ostreidae/microbiología , Mariscos/microbiología , Vibrio parahaemolyticus/crecimiento & desarrollo , Animales , China , Frío , Recuento de Colonia Microbiana , Granjas , Contaminación de Alimentos/análisis , Manipulación de Alimentos , Humanos , Ostreidae/química , Ostreidae/crecimiento & desarrollo , Refrigeración , Mariscos/análisis , Temperatura Ambiental , Estados Unidos
14.
Int J Food Microbiol ; 313: 108390, 2020 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-31678818

RESUMEN

Growth of L. monocytogenes is among the most important factors affecting the risk of human listeriosis. In ready to eat leafy greens, the use of anti-Listeria treatments represents a good alternative to inhibit growth during storage. Several commercially available antimicrobial agents have been suggested as effective intervention strategies. Among them, phage preparations and bacteriocin-producing strains have shown promising results against L. monocytogenes. In this study, we investigate the efficacy of two commercially available surface treatments, the bacteriophage formulation PhageGuard Listex (Micreos Food Safety B.V., NL) and the bacteriocin-producing culture SafePro® (CHR Hansen, DK) to inactivate L. monocytogenes in fresh-cut curly endive after processing and during storage. Fresh-cut endive was inoculated with a cold-adapted L. monocytogenes cocktail of 6 strains (4.4 ±â€¯0.0 log cfu/g) and treated with the anti-Listeria treatments. The treatments were applied using a spray system at two different places within the processing line, on the conveyor belt and in the centrifuge. A total of 5 different treatments were applied: i) Untreated (CT); ii) PhageGuard Listex on the conveyor belt (Listex_Conveyor); iii) PhageGuard Listex during centrifugation (Listex_Centrifuge); iv) SafePro on the conveyor belt (SafePro_Conveyor); and v) SafePro during centrifugation (SafePro_Centrifuge). Samples were stored 3 days at 5 °C plus 5 days at 8 °C. PhageGuard Listex treatment reduced L. monocytogenes in fresh-cut endive by 2.5 logs, regardless of the place of treatment application (conveyor belt or centrifuge). On the other hand, SafePro only reduced L. monocytogenes by 0.2 and 0.4 logs, at the conveyor belt and centrifuge, respectively. Maximum L. monocytogenes reductions of about 3.5 log units were observed in fresh-cut endive treated with PhageGuard Listex after 3 days of storage. At the end of the shelf life (8 days), the initial trends were maintained and the fresh-cut curly endive treated with PhageGuard Listex showed the lowest L. monocytogenes concentration. However, by the end of the shelf-life, L. monocytogenes showed higher levels (1.3-fold) than immediately after the application of the treatment. One hypothesis could be that L. monocytogenes cells, which were able to survive the anti-Listeria treatments, were also able to proliferate under the specific storage conditions. Based on the obtained results, PhageGuard Listex seems to be a promising decontamination agent for leafy greens aiming to reduce growth of the bacteria but further work is needed.


Asunto(s)
Conservación de Alimentos/métodos , Listeria monocytogenes/crecimiento & desarrollo , Verduras/microbiología , Bacteriocinas/metabolismo , Bacteriófagos/fisiología , Recuento de Colonia Microbiana , Microbiología de Alimentos , Conservación de Alimentos/instrumentación , Inocuidad de los Alimentos , Humanos , Listeria monocytogenes/metabolismo , Listeria monocytogenes/virología , Proyectos Piloto , Hojas de la Planta/microbiología , Temperatura Ambiental
15.
World J Microbiol Biotechnol ; 35(12): 195, 2019 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-31784916

RESUMEN

The search for effective plant-growth-promoting strains of rhizospheric bacteria that would ensure the resistance of plant-microbial associations to environmental stressors is essential for the design of environmentally friendly agrobiotechnologies. We investigated the interaction of potato (cv. Nevsky) microplants with the plant-growth-promoting bacteria Azospirillum brasilense Sp245 and Ochrobactrum cytisi IPA7.2 under osmotic stress in vitro. The bacteria improved the physiological and biochemical variables of the microplants, significantly increasing shoot length and root number (1.3-fold, on average). Inoculation also led a more effective recovery of the plants after stress. During repair, inoculation contributed to a decreased leaf content of malonic dialdehyde. With A. brasilense Sp245, the decrease was 1.75-fold; with O. cytisi IPA7.2, it was 1.4-fold. During repair, the shoot length, node number, and root number of the inoculated plants were greater than the control values by an average of 1.3-fold with A. brasilense Sp245 and by an average of 1.6-fold with O. cytisi IPA7.2. O. cytisi IPA7.2, previously isolated from the potato rhizosphere, protected the physiological and biochemical processes in the plants under stress and repair better than did A. brasilense Sp245. Specifically, root weight increased fivefold during repair, as compared to the noninoculated plants, while chlorophyll a content remained at the level found in the nonstressed controls. The results indicate that these bacteria can be used as components of biofertilizers. A. brasilense Sp245 has favorable prospects for use in temperate latitudes, whereas O. cytisi IPA7.2 can be successfully used in saline and drought-stressed environments.


Asunto(s)
Interacciones Microbiota-Huesped/fisiología , Presión Osmótica , Desarrollo de la Planta , Solanum tuberosum/microbiología , Estrés Fisiológico/fisiología , Azospirillum brasilense/fisiología , Clorofila A , Recuento de Colonia Microbiana , Sequías , Malonatos , Ochrobactrum/fisiología , Hojas de la Planta , Raíces de Plantas/microbiología , Brotes de la Planta , Rizosfera
16.
World J Microbiol Biotechnol ; 36(1): 3, 2019 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-31832784

RESUMEN

Available disinfection methods and therapies against Helicobacter pylori have multiple disadvantages, such as increased prevalence of antibiotic-resistant strains, which requires the search for novel effective antimicrobial agents against H. pylori. Among them, naturally-occurring antimicrobial compounds, like essential oil components (EOCs), have been reported as substances with anti-H. pylori potential. To avoid the disadvantages associated with using EOCs in their free form, including volatility, low water solubility and intense sensory properties, their immobilisation in inert supports has recently been developed. This study sought to evaluate the inhibitory properties of EOCs immobilised on silica microparticles against H. pylori and to elucidate the mechanism of action of the immobilised antimicrobials. After the preparation and characterisation of the antimicrobial supports, the susceptibility of H. pylori in the presence of the immobilised compounds was assessed by plate count, fluorescent viability staining and direct viable count-fluorescent in situ hybridisation analyses. The antimicrobial supports were found to inhibit H. pylori growth, and to induce morphological and metabolic alterations to the H. pylori membrane, with a minimum bactericidal concentration value between 25 and 50 µg/ml according to the tested EOC. These findings indicate that immobilised EOCs can be used as potential antimicrobial agents for H. pylori clearance and treatment.


Asunto(s)
Antiinfecciosos/farmacología , Helicobacter pylori/efectos de los fármacos , Aceites Volátiles/farmacología , Recuento de Colonia Microbiana , Farmacorresistencia Bacteriana Múltiple , Inmovilización , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , Dióxido de Silicio/química
17.
J Contemp Dent Pract ; 20(10): 1190-1194, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31883255

RESUMEN

AIM: Green tea is an antimicrobial agent that has beneficial effects on oral and dental health. The aim of this study was to compare the effect of "green tea" and "green tea with xylitol" mouthwashes on the salivary Streptococcus mutans and Lactobacillus colony count in children. MATERIALS AND METHODS: In this double-blind randomized controlled clinical trial, 64 children aged 6-12 years were randomly divided into two groups. Subjects were instructed to wash their mouth with 5% "green tea" or 20% "green tea with xylitol" mouthwashes twice a day for a period of 2 weeks. Salivary counts of bacteria were determined at the baseline and after 2 weeks of intervention. RESULTS: A significant difference was found between the average number of bacterial colonies between the two groups after intervention (p < 0.001). CONCLUSION: Findings of this study suggest that the effect of the "green tea with xylitol" mouthwash on reducing the number of salivary colonies of S. mutans and Lactobacillus is significantly higher than that of the "green tea" mouthwash. CLINICAL SIGNIFICANCE: The green tea mouthwash can be advised for dental and oral health of children. How to cite this article: Hajiahmadi M, Yegdaneh A, Homayoni A, et al. Comparative Evaluation of Efficacy of "Green Tea" and "Green Tea with Xylitol" Mouthwashes on the Salivary Streptococcus Mutans and Lactobacillus Colony Count in Children: A Randomized Clinical Trial. J Contemp Dent Pract 2019;20(10):1190-1194.


Asunto(s)
Antisépticos Bucales , Streptococcus mutans , Niño , Recuento de Colonia Microbiana , Método Doble Ciego , Humanos , Lactobacillus , Saliva , , Xilitol
18.
Int. microbiol ; 22(4): 511-520, dic. 2019. graf, tab
Artículo en Inglés | IBECS | ID: ibc-185069

RESUMEN

The phylum Firmicutes comprises seven classes where most species are either aerobic or anaerobic endospore former. Inside Firmicutes, species allocated in the genus Bacillus and related genera are collectively named aerobic endospore-forming bacteria (AEFB), and the soil is their major reservoir. AEFB have great importance in health, agriculture, and biotechnology although the more studied species are Bacillus subtilis and the human pathogens Bacillus cereus and Bacillus anthracis. AEFB have great importance in health, agriculture, and biotechnology; although the knowledge about these organisms is based on few species, notably, Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. In this work, we generated partial 16S rRNA gene sequences of both strands of 192 AEFB strains isolated from soils of Distrito Federal, Brazil (SDF strains). The resulting consensus sequences were used to obtain taxonomic assignment and establish the phylogenetic relationships among these strains. Through this approach, we could observe that classified SDF strains were distributed among genera Bacillus (169 strains; 88.02%), Paenibacillus (11; 5.73%), Lysinibacillus (6; 3.13%), Brevibacillus (4; 2.08%), Terribacillus (1; 0.52%), and Rummeliibacillus (1; 0.52%). Phylogenetic trees revealed these 192 SDF strains can be segregated into eight groups spanning families Bacillaceae and Paenibacillaceae belonging to the order Bacillales. To expand the knowledge about the diversity of these SDF strains, further studies regarding characterization with different methodologies are underway


No disponible


Asunto(s)
Contaminantes del Suelo/análisis , Análisis del Suelo , Esporas Bacterianas/aislamiento & purificación , Recuento de Colonia Microbiana , ARN Ribosómico 16S/genética , Bacterias Anaerobias/aislamiento & purificación , Bacillales/aislamiento & purificación , Esporas Fúngicas/genética , Brasil , Bacillales/genética , Perfilación de la Expresión Génica/métodos
19.
An Bras Dermatol ; 94(5): 527-531, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31777352

RESUMEN

BACKGROUND: Malassezia, a skin saprophyte, is frequently isolated from patients with seborrheic dermatitis, which is one of the most common dermatoses in HIV-infected patients. Its role in pathophysiology has not been defined. OBJECTIVE: To determine whether patients living with HIV and seborrheic dermatitis have more Malassezia than those without seborrheic dermatitis. METHOD: This is an descriptive, observational, prospective cross-sectional study to which all adult patients living with HIV that attend the infectious disease outpatient clinic at the Dr. Manuel Gea González General Hospital were invited. Patients presenting with scale and erythema were included in Group 1, while patients without erythema were included in Group 2. Samples were taken from all patients for smear and culture. RESULTS: Thirty patients were included in each group. All patients with seborrheic dermatitis had a positive smear, with varying amounts of yeasts. In the control group, 36.7% of patients had a negative smear. The results are statistically significant, as well as the number of colonies in the cultures. Study limitations The study used a small sample size and the subspecies were not identified. CONCLUSIONS: Patients with clinical manifestations of seborrheic dermatitis have larger amounts of Malassezia. Further studies need to be performed to analyze if the greater amount is related to imbalances in the microbiota of the skin.


Asunto(s)
Dermatitis Seborreica/microbiología , Infecciones por VIH/microbiología , Malassezia/aislamiento & purificación , Adolescente , Adulto , Anciano , Recuento de Linfocito CD4 , Recuento de Colonia Microbiana , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Distribución por Sexo , Piel/microbiología , Adulto Joven
20.
Int J Pharm Compd ; 23(6): 467-471, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31751943

RESUMEN

Selecting an appropriate sanitizer (i.e., "rub") for application to hands and gloves before and, if necessary, during sterile compounding is as important as is its consistent and judicious use. Alcohols and chlorhexidine gluconate, which have long been recognized as safe and powerful biocides, are often essential ingredients in such sanitizing products. In this second article in a 2-part series on alcohol-based hand and glove sanitizers, we review the selection of and need for those rubs in sterile compounding, present considerations for their safe storage, compare the features of several appropriate sanitizing agents, and answer compounders' frequently asked questions about their use. Glove sanitizing is discussed as part of the hand-sanitizing process. In part 1 of this series, we explained, among other topics, the mechanism of action and composition of alcohol-based sanitizers and presented a protocol for their application to hands and gloves.


Asunto(s)
Desinfectantes , Guantes Protectores , Desinfección de las Manos , Recuento de Colonia Microbiana , Mano , Desinfección de las Manos/normas , Humanos , Control de Calidad
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