Maintenance of sterility in SMS packaging in dental environments: concern with biosafety

Healthcare services must be guided by biosafety practices and microbial control. This control is highly influenced by humidity, which directly impacts the maintenance of sterility of the materials used in the appointments. High concentration of moisture, in the form of aerosol, splashes and spills, is caused during dental care. During the COVID-19 times the contamination by aerosol and droplets worries greatly. Considering that it could cause harm to the sterility of an autoclaved material, especially in dental environments, the objective was to evaluate the behavior of SMS sterilization packages (Spunbonded / Meltblown / Spunbonded) against microbial penetration in an aqueous vehicle. SMS of three brands were challenged, equally divided into two groups: virgin and processed (subjected to a single autoclaving cycle). Each specimen was aseptically deposited on Macconkey agar. Subsequently, 5 µL of Escherichia coliATCC 25922 saline solution [108CFU mL-1] was deposited in center of the SMS specimen and the dish incubated at36°C/ 48h. Reading was performed by the presence or absence of bacterial growth typical of the species under the SMS, observed on the back of Petri dish. The lowest penetration rate observed was 60% for one of the brands in the virgin condition, and 75% for two brands in the processed condition. Statistical analysis showed an association between bacterial penetration and the evaluated group, this association being valid only in the virgin condition. The different SMS behave similarly in terms of resistance to bacterial penetration after being processed. The data show that moisture can assist in bacterial transport through sterilized SMS. Therefore, SMS packages are not able to prevent bacterial penetration, and possibly other microorganisms, when in aqueous vehicles, offering a potential risk of breaking the aseptic chain. Thus, care must be taken in routines for handling and storage sterile packaging.

Magnetohydrodynamic bioconvective flow of Williamson nanofluid containing gyrotactic microorganisms subjected to thermal radiation and Newtonian conditions.

Magnetohydrodynamic (MHD) bioconvective flow of Williamson nanomaterial in frame of gyrotactic microorganisms is addressed. Nanomaterial characterizes gyrotactic microorganism. Bioconvection is generated by buoyancy forces in the communication of nanoparticles and motile microorganisms. The use of gyrotactic microorganisms into nanofluid here is just to stabilize the nanoparticles to suspend due to a phenomenon called bioconvection. Newtonian conditions for thermal, solutal and motile microorganism are employed. The transformed nonlinear systems of momentum, energy, nanoparticles concentration and motile microorganisms density are solved numerically through the bvp4c technique. Significance of various variables on physical quantities is explained graphically.

Some specific microbiological parameters and prevalence of salmonella spp. in retail chicken meat from erzurum province, turkey and characterization of antibiotic resistance of isolates / Alguns parâmetros microbiológicos específicos e prevalência de SalmonellA spp. cortes de carne de frango da província de Erzurum, Turquia e caracterização da resistência aos antibióticos de isolados

Specific microbiological parameters and the presence of Salmonella spp. were investigated in 72 chicken meat samples (36 wings and 36 drumsticks) collected from markets and butcher shops. The specific microbiological parameters were determined using a conventional cultural method and the presence of Salmonella spp. in chicken samples was determined using conventional and immunomagnetic separation (IMS)-polymerase chain reaction (PCR) methods. In addition, antimicrobial susceptibility of the isolates was revealed using the Kirby-Bauer disc diffusion method. The results indicated that 30 of the 72 samples were positive for Salmonella spp. by the conventional method, and 42 of the 72 were positive by the IMS-PCR method. However, 30 of the 72 samples were positive for Salmonella spp. by both methods. The Salmonella spp. isolates were confirmed by the VITEK2 Compact System and PCR. The susceptibilities of the isolates against 10 antibiotics were determined. The results indicated that isolates (27/30) showed the highest susceptibility to gentamycin (90.00%), while the highest resistance was to nalidixic acid and tetracycline at the 100 and 93.34% levels, respectively. These results indicate a high prevalence of Salmonella spp. in poultry meat from Erzurum city, Turkey, and the antimicrobial resistance profile of these isolates should be considered for public health. The results also show that the IMS-PCR technique was superior to the conventional method for detecting Salmonella in poultry meat.KEYWORDS:Chicken meat. Salmonella. IMS. PCR. Antimicrobial. INTRODUCTION Chicken is one of the most popular food products worldwide, because of nutritional, sensorial and economic factors. Chicken is widely consumed in homes and fast-food establishments, but can become contaminated during processing. The contamination of poultry products with Salmonella and other microorganismsis due to unhygienic conditions during the production, processing, distribution, marketing and preparationstages (DOOKERAN et al., 2012). The genus Salmonella includes short rod-shaped, facultative anaerobe, Gram-negative bacteria. Warm-blooded animals and humans are natural hosts for Salmonella spp. Detecting Salmonella spp. during production and before consumption is important to prevent food-borne salmonellosis. A Salmonella infection in humans is usually caused by consuming undercooked meat or other cross-contaminated foods, such as vegetables,milk and eggs (HASSANEIN et al., 2011). According to a report published by the Centres for Disease Control and Prevention (CDC), it is estimated that about 1.2 million people in the US have been exposed to Salmonella infections, and that an average of 23.000 hospitalisations and 450 deaths occur from these infections. The prevalence rates of Salmonella spp. in chicken meat sold in Turkey are 34-68.75%. Not only in Turkey, but in most developing countries, the absence of an epidemiological surveillance system for salmonellosis cases makes it difficult to effectively assess prevalence (KÄFERSTEIN, 2003). However, Received: 09/05/18 Accepted: 05/12/18

Parâmetros microbiológicos específicos e a presença de Salmonella spp. foram investigados em 72 amostras de carne de frango (36 asas e 36 baquetas) coletadas em mercados e açougues. Os parâmetros microbiológicos específicos foram determinados utilizando um método cultural convencional e a presença de Salmonella spp. em amostras de frango foi determinada utilizando métodos de reação em cadeia da polimerase (PCR) por separação convencional e imunomagnética (IMS). Além disso, a suscetibilidade antimicrobiana dos isolados foi revelada pelo método de difusão do disco de Kirby-Bauer. Os resultadosindicaram que 30 das 72 amostras foram positivas para Salmonella spp. pelo método convencional, e 42 das 72 foram positivas pelo método IMS-PCR. No entanto, 30 das 72 amostras foram positivas para Salmonella spp. por ambos os métodos. Os isolados de Salmonella spp. foram confirmados pelo sistema VITEK2 Compact e PCR. As susceptibilidades dos isolados a 10 antibióticos foram determinadas. Os resultados indicaram que os isolados (27/30) apresentaram maior suscetibilidade à gentamicina (90,00%), enquanto a maior resistência foi ao ácido nalidíxico e à tetraciclina nos níveis de 100 e 93,34%, respectivamente. Estes resultados indicam uma alta prevalência de Salmonella spp. em carne de frango da cidade de Erzurum, Turquia, e o perfil de resistência antimicrobiana desses isolados deve ser considerado para a saúde pública. Os resultados também demonstram que a técnica de IMS-PCR foi superior ao método convencional para detecção de Salmonella em carne de frango.

Caracterización de pacientes pediatricos con hemocultivos positivos del servicio de cuidado intensivo pediatrico del Hospital San José Bogotá, abril 2012 a 2017 / Description of Pediatric Patients with Positive Blood Cultures from the Pediatric Intensive Care Unit at Hospital de San José in Bogotá, April 2012 to 2017

Introducción: El cultivo de la sangre es el método más utilizado en la búsqueda de infecciones del paciente pediátrico porque orienta la terapia antimicrobiana. Objetivo: Determinar la incidencia de hemocultivos positivos y su caracterización microbiológica en pacientes de cuidado intensivo pediátrico del Hospital de San José, Bogotá-Colombia. Materiales y métodos: Descripción de hemocultivos positivos en pacientes pediátricos de la unidad desde abril de 2012 a 2017. Se determinó la incidencia de hemocultivos positivos y se describió la población estudiada y los gérmenes aislados incluido su perfl de antibiograma. Resultados: Ingresaron 1773 pacientes a la UCIP, 241 pacientes (13,6%) fueron hemocultivados, de los cuales 80 (33,2%) fueron positivos, pero 50% de estos fueron catalogados como contaminaciones. La mediana de edad fue de 21 meses, con 64% de sexo masculino. El 57% fue ventilado y 45% tuvieron un catéter central. La mortalidad fue de 15,4%. La patología más frecuentemente fue respiratoria (75%). De los gérmenes no contaminantes el más frecuente aislado fue Staphylococcus aureus (30%), seguido de Klebsiella pneumoniae (17,5%) y Streptococcus pneumoniae (17,5%). El germen contaminante más frecuente fue Staphylococcus epidermidis (47,5%). Conclusión: La frecuencia de hemocultivos positivos es baja y es frecuente que se aíslen gérmenes contaminantes. El patrón fue similar a lo reportado por la red GREBO.

Introduction. Blood culture is the method most used in the search for pediatric infections because it guides the antimicrobial therapy. Objective. To determine the incidence of positive blood cultures and their microbiological characterization in patients of the pediatric intensive care service of San José Hospital, Bogotá-Colombia. Materials and methods: Description of positive blood cultures in pediatric patients of the unit from April 2012 to 2017. The incidence of positive blood cultures was determined and the population studied and the isolated germs were described, including their antibiogram profle. Results: 1773 patients were admitted to the PICU, 241 patients (13.6%) were blood cultures, of which 80 (33.2%) were positive, but 50% of these were classifed as contaminations. The median age was 21 months, with 64% male. 57% were ventilated and 45% had a central catheter. Mortality was 15.4%. The most frequent pathology was respiratory (75%). Of the non-polluting organisms, the most frequent isolate was Staphylococcus aureus (30%), followed by Klebsiella pneumoniae (17.5%) and Streptococcus pneumoniae (17.5%). The most frequent contaminant was Staphylococcus epidermidis (47.5%). Conclusion: The frequency of positive blood cultures is low and polluting organisms are often isolated. The pattern was similar to that reported by the GREBO network.

Determinação do pH mínimo de crescimento de Listeria monocytogenes frente a diferentes ácidos orgânicos / Determination of the minimum pH growth of Listeria monocytogenes front of different organic acids

Os ácidos orgânicos são empregados no processamento de alimentos para retardar a multiplicação microbiana. O objetivo foi determinar o pH mínimo de crescimento de Listeria monocytogenes, mediante ao uso dos ácidos lático, acético e cítrico. Para determinar o pH mínimo de crescimento de L. monocytogenes em meio de cultura, frente aos diferentes ácidos orgânicos, foi utilizado caldo Brain Heart Infusion (BHI), que teve o pH ajustado para valo res de 4,0 a 6,0, em um intervalo de 0,2. O crescimento de L. monocytogenes, em diferentes valores de pH, foi monitorado pela medida da Densidade Óptica a 600 nm. Os ensaios foram realizados a 35 ºC, durante 7 dias. As taxas de crescimento foram ajustadas ao modelo de raiz quadrada, sendo um modelo para cada antimicrobiano estudado. Observou-se que o menor valor de pH mínimo para o crescimento de L. monocytogenes ocorreu ao ser empregado o ácido cítrico e o maior valor, ao ser empregado o ácido acético.

Adaptação cruzada de Escherichia coli enteropatogênica ao cinamaldeído e citral / Cross adaptation of enteropatogenic Escherichia coli tocinnamaldehyde and citral

O objetivo do trabalho foi verificar a capacidade de adaptação cruzada de EPEC CDC O55 aos compostos majoritários citral e cinamaldeído. Para isso, foi determinada a Concentração Mínima Bactericida (CMB) do citral e em seguida,as células de EPEC foram expostas a concentração subletal de cinamaldeído (CMB/16). Posteriormente testadas frente a diferentes concentrações do composto citral (CMB/2; CMB; 1,2CMB; 1,4CMB; 1,6CMB; 1,8CMB e 2CMB), estas foram incubadas e plaqueadas em TSA (Ágar Triptona de Soja) empregando-se a técnica de microgotas. As células de EPEC foram classificadas como capazes de se adaptarem, quando cresceram em placas após cultivo em presença do composto em concentração igual ou maior que a CMB. A CMB do citral foi de 1,0% (v/v). As células de EPEC não apresentaram a capacidade de adaptação cruzada. Os resultados demonstram que os compostos majoritários são alternativas eficazes no controle de EPEC.

Adaptação de Escherichia coli enterotoxigênica ao eugenol / Adaptation of enterotoxigenic Escherichia coli to eugenol

O objetivo do trabalho foi verificar a capacidade de adaptação de ETEC- ATCC 35401 ao antimicrobiano eugenol. Para isso, a Concentração Mínima Bactericida (CMB) de eugenol foi determinada e em seguida,as células de ETEC foram expostas a concentrações subletais de eugenol (CMB/4, CMB/8 e CMB/16). Posteriormente testadas frente a diferentes concentrações do composto (CMB/2; CMB; 1,2CMB; 1,4CMB; 1,6CMB; 1,8CMB e 2CMB), estas foram incubadas e plaqueadas em TSA (Ágar Triptona de Soja) empregando a técnica de microgotas. As células de ETEC foram classificadas como capazes de se adaptarem quando essas cresceram em placas após cultivo em presença do componente em concentração igual ou maior que a CMB do eugenol (1,0% (v/v)). As células de ETEC apresentaram a capacidade de adaptação por crescerem na CMB, após exposta a CMB/16. Os resultados demonstram a necessidade de obtenção da concentração de uso adequado de eugenol a fim de evitar a adaptação.

Gas Chromatography-Mass Spectrometry Microbial Metabolomics for Applications in Strain Optimization.

Metabolomics is the systems-scale measurement of biochemical intermediates in biological systems; by virtue of its deep and broad study of metabolism, it has great potential for applications in metabolic engineering. While a number of the analytical techniques used widely in metabolomics are familiar to metabolic engineers performing post hoc analyses of product titers, the requirements for accurately capturing metabolism at a systems scale rather than just measuring a single secreted product are much more complicated. Nonetheless, metabolomics (which is still not widely available as an affordable consumer service like many molecular biology services) is within reach of many properly equipped metabolic engineering groups. To this end, we present a detailed metabolomics protocol with application to strain optimization. Specifically, we focus on characterizing metabolism in the yeast Saccharomyces cerevisiae using gas chromatography coupled to mass spectrometry. The measurement of metabolic intermediates that results from such approaches has the potential to enable more informed and rational efforts towards pathway engineering and strain optimization.

The contribution of respiratory microbiome analysis to a treatable traits model of care.

The composition of the airway microbiome in patients with chronic airway diseases, such as severe asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis and cystic fibrosis (CF), has the potential to inform a precision model of clinical care. Patients with these conditions share overlapping disease characteristics, including airway inflammation and airflow limitation. The clinical management of chronic respiratory conditions is increasingly moving away from a one-size-fits-all model based on primary diagnosis, towards care targeting individual disease traits, and is particularly useful for subgroups of patients who respond poorly to conventional therapies. Respiratory microbiome analysis is an important potential contributor to such a 'treatable traits' approach, providing insight into both microbial drivers of airways disease, and the selective characteristics of the changing lower airway environment. We explore the potential to integrate respiratory microbiome analysis into a treatable traits model of clinical care and provide a practical guide to the application and clinical interpretation of respiratory microbiome analysis.

Isolation and Identification of a Potential Amylolytic Probiotic Bacterium from the Gut of Jundiá Catfish, Rhamdia quelen

ABSTRACT This study aimed to isolate a potential probiotic amylolytic strain from the gut of jundiá catfish to improve carbohydrate digestibility in fish. Two of 31 strains isolated from the foregut of Rhamdia quelen were able to grow on starch-agar medium and were considered amylolytic. The strain that presented higher amylolytic potential, based on a qualitative amylase assay, was chosen. The strain was phenotypically characterized and analysed to determine bile and pH tolerance and extracellular quantitative amylase activity. The probiotic candidate, identified as Aeromonas veronii, showed the ability to survive stresses from a range of pH and bile salt conditions and secreted an interesting enzymatic profile, which may exhibit a synergistic effect when combined with the enzymes secreted by the jundiá catfish, improving carbohydrate digestion in the host. The results demonstrated the potential of A. veronii to improve the digestion process in jundiá by providing exogenous enzymes for the breakdown and absorption of nutrients.

Microbial antioxidant defense enzymes.

Free radicals are often described as chemical compounds characterized by unpaired electrons in their outer orbital rendering them highly reactive species. In mammalians, studies on free radicals were focused on reactive oxygen species (ROS) or reactive nitrogen species (RNS) due to their relative importance in physiological as well as in pathological processes. These cellular compounds are produced by different physiological systems such as the aerobic metabolism and play a major role in cell signaling pathways but also in the host immune defenses against pathogenic microorganisms. ROS and RNS are highly reactive species with potentially harmful effects on any cellular components (lipids, proteins and nucleic acids) when produced with a high level. To maintain ROS and RNS at a non-toxic concentration, enzymatic and non-enzymatic cellular antioxidants coordinate the balance between their production and their degradation. Superoxide dismutases, catalases, glutathione system, thioredoxin system, peroxidase systems, flavohemoglobins and nitrate or nitrite reductases represent the prominent enzymatic antioxidants used to scavenge excess of internal as well as external ROS and RNS. Bacteria, fungi and parasites also display similar enzymatic activities to escape the host oxidative defenses during the immune response against infectious processes. Here we summarize current knowledge on the enzymatic systems that allow microorganisms to fight against ROS and RNS, and shed light on the role that take some of them in microbial infections. Such microbial protective systems are considered as virulence factors, and therefore represent key targets for diagnosis of the infections or development of anti-infectious drugs.

Data-driven modeling reveals cell behaviors controlling self-organization during Myxococcus xanthus development.

Collective cell movement is critical to the emergent properties of many multicellular systems, including microbial self-organization in biofilms, embryogenesis, wound healing, and cancer metastasis. However, even the best-studied systems lack a complete picture of how diverse physical and chemical cues act upon individual cells to ensure coordinated multicellular behavior. Known for its social developmental cycle, the bacterium Myxococcus xanthus uses coordinated movement to generate three-dimensional aggregates called fruiting bodies. Despite extensive progress in identifying genes controlling fruiting body development, cell behaviors and cell-cell communication mechanisms that mediate aggregation are largely unknown. We developed an approach to examine emergent behaviors that couples fluorescent cell tracking with data-driven models. A unique feature of this approach is the ability to identify cell behaviors affecting the observed aggregation dynamics without full knowledge of the underlying biological mechanisms. The fluorescent cell tracking revealed large deviations in the behavior of individual cells. Our modeling method indicated that decreased cell motility inside the aggregates, a biased walk toward aggregate centroids, and alignment among neighboring cells in a radial direction to the nearest aggregate are behaviors that enhance aggregation dynamics. Our modeling method also revealed that aggregation is generally robust to perturbations in these behaviors and identified possible compensatory mechanisms. The resulting approach of directly combining behavior quantification with data-driven simulations can be applied to more complex systems of collective cell movement without prior knowledge of the cellular machinery and behavioral cues.

Microbial stress: From molecules to systems (Sitges, November 2015).

The meeting "Microbial Stress: from Molecules to Systems" - the third in this series - was held in Sitges (Spain) in November 2015. The meeting offered the opportunity for international scientists to share their viewpoints and recent outcomes concerning microbial stress responses. Particular attention was given to the characterisation of mechanisms triggered by stress, from detailed molecular biology through whole organism systems biology up to the level of populations. A deeper understanding of microbial responses to stress is indeed attainable only considering the phenomenon as a whole. Exhaustive knowledge of the various stress response systems, and of their interconnections, is important for different applications, from the prevention and counteraction of bacterial infectious diseases to the engineering of robust cell factories. The presentations covered all of these aspects, enabling an active interaction among participants. It also stimulated discussions and cross-fertilisation among disciplines, which was one of the aims of the meeting. Moreover, since many stress response mechanisms are broadly conserved, data obtained at the microbial scale may facilitate the comprehension of complex phenomena, such as aging, evolution of neurological diseases and cancer.

Characterisation of a novel Type I crustin involved in antibacterial and antifungal responses in the red claw crayfish, Cherax quadricarinatus.

Antimicrobial peptides are important immune effectors involved in mediating innate immune responses against intruding pathogens. Here, we successfully isolated and characterized a novel Type I crustin from the red claw crayfish Cherax quadricarinatus. The full-length cDNA encoded by this gene, designated CqCrs, comprised 608 bp, containing a 5'-untranslated region (UTR) of 55 bp, a 3'-UTR of 229 bp with a poly (A) tail, and an open reading frame (ORF) of 324 bp encoding a polypeptide of 107 amino acids. The deduced amino acid sequence of CqCrs exhibited a configuration typical of other crustacean Type I crustin orthologs, including one signal peptide region at the N-terminus between residues 1 and 16 and a long whey acidic protein (WAP) domain at the C-terminus between residues 60 and 107, along with a WAP-type "four-disulfide core" motif. Phylogenetic analysis showed that CqCrs was clustered first with other crustacean Type I crustins, then with other crustacean Type II crustins, and finally with other crustacean Type III crustins. Transcription of CqCrs was detected in all tissues, especially in immune tissues and was differentially induced in hemocytes post-stimulation with ß-1, 3-glucan, lipopolysaccharides (LPS) and peptidoglycans (PG) at selected time-points. To clarify the biological activity of CqCrs, the recombinant CqCrs protein (rCqCrs) was constructed and expressed in Escherichia coli BL21 (DE3). Purified rCqCrs bound to diverse bacteria and inhibited the growth of different microbes to varying degrees. These findings suggest that CqCrs is involved in a specific innate immune recognition and defense mechanisms against bacterial and fungal in C. quadricarinatus.

Vegetais minimamente processados prontos para o consumo: influência da etapa de desinfecção na inativação de Salmonella Typhimurium, na ocorrência da contaminação cruzada e na avaliação quantitativa de risco microbiológico em relação a este patógeno / Minimally processed ready-to-eat vegetables: influence of washing-disinfection step on Salmonella Typhimurium inactivation, on occurrence of cross-contamination and on quantitative microbiological risk assessment regarding this pathogen

Dados mundiais apontam haver uma associação entre o aumento do comércio de vegetais minimamente processados prontos para o consumo (VPC) e o aumento da ocorrência de surtos de enfermidades transmitidas por alimentos. Durante o processamento industrial de VPC, a desinfecção é a principal etapa de inativação de micro-organismos patogênicos presentes, mas nessa etapa também pode ocorrer contaminação cruzada, com transferência de contaminantes de produtos contaminados para não-contaminados. Neste trabalho, foram coletadas informações sobre as práticas empregadas na etapa de desinfecção em dez importantes indústrias produtoras de VPC no Estado de São Paulo, avaliando-se, em seguida, a influência dessas práticas na qualidade microbiológica dos produtos e na inativação de Salmonella Typhimurium, bem como na ocorrência de contaminação cruzada por este patógeno. Um modelo de avaliação quantitativa de risco microbiológico foi elaborado para estimar o impacto da contaminação cruzada durante a etapa de desinfecção no risco de infecção por Salmonella devido ao consumo de VPC. Observou-se que, em todas as indústrias visitadas, a desinfecção dos vegetais era feita com produtos à base de cloro em concentrações de 50 a 240 mg/L, que resultava em redução de até 1,2 log na carga microbiana dos vegetais que entravam na linha de processamento. Ao avaliar a influência das características da água de processamento (pH, temperatura, concentração de matéria orgânica e concentração de dicloroisocianurato de sódio) e do tempo de contato entre a água clorada e os vegetais na redução de Salmonella, observou-se que a concentração do produto à base de cloro foi o parâmetro que apresentou maior influência (p<0.05). Concentrações de dicloroisocianurato de sódio acima de 10 mg/L foram necessárias para controle da contaminação cruzada durante a etapa de lavagem. O modelo de avaliação de risco construído indicou quantitativamente haver uma relação entre a concentração de dicloroisocianurato de sódio na água de desinfecção e o risco de ocorrência de surtos causados por Salmonella em VPC. Cenários simulando uso de dicloroisocianurato de sódio em concentrações abaixo de 5 mg/L indicaram que mais de 96% dos casos preditos de infecção por Salmonella poderiam ser atribuídos à ocorrência de contaminação cruzada, enquanto que em cenários com concentrações acima de 50 mg/L, casos de infecção devidos à contaminação cruzada não foram preditos. Estes resultados mostram que o controle da qualidade da água e o monitoramento da concentração de sanitizante na etapa de desinfecção são essenciais para evitar a ocorrência de contaminação cruzada e garantir a produção de VPC seguros para o consumo

Surveillance data in several countries show an association between consumption of minimally processed ready-to-eat (RTE) vegetables and increased occurrence of foodborne diseases outbreaks. During RTE vegetables processing, washing-disinfection is the main step aiming to ensure inactivation of pathogenic microorganisms, but also is the step in which cross-contamination may occur, with transfer of contaminants from contaminated to non-contaminated products. In this study, we collected information on the practices employed during the washing-disinfection step in ten RTE vegetables processing plants located in the State of Sao Paulo, Brazil, and evaluated the influence of these washing practices on the microbial quality of the products and inactivation of Salmonella Typhimurium, as well as on the occurrence of cross-contamination by this pathogen. A quantitative microbial risk assessment model was built in order to estimate the impact of cross-contamination during the washing step on the risk of infection by Salmonella due to the consumption of RTE vegetables. In all visited processing plants, the disinfection step was done using chlorine-based products, in concentrations ranging from 50 to 240 mg/L, achieving a reduction of up to 1.2 log in the microbial load of vegetables entering the processing line. When the influence of washing water parameters (pH, temperature, organic load and sodium dichloroisocyanurate concentration) and time of contact between chlorinated water and vegetables on reduction of Salmonella were evaluated, sodium dichloroisocyanurate concentration influenced the most (p<0.05). Concentrations above 10 mg/L were necessary for avoiding cross-contamination during washing step. The risk assessment model indicated quantitatively a relationship between sodium dichloroisocyanurate concentration and the risk of illness caused by Salmonella in RTE vegetables. When simulation was done with less than 5 mg/L of sodium dichloroisocyanurate, most (>96%) of the illnesses arose from cross-contamination. However, when the concentration was 50 mg/L or higher, no illnesses arising from cross-contamination were predicted. These results show that controlling the quality of the water and monitoring the concentration of the sanitizer in the disinfection step are essential to avoid occurrence of cross contamination and ensure production of RTE vegetables that are safe for consumption

Eficácia de dois métodos de degermação das mãos / Effectiveness of two methods of hands degermation

A lavagem das mãos reduz as bactérias da pele, diminuindo as taxas de infecções. Há várias técnicas de higienização das mãos, devendo o profissional escolher a mais adequada. OBJETIVOS: este trabalho avaliou a eficácia da lavagem cirúrgica das mãos e antebraços com escova impregnada com clorexidina a 2%, comparando com o método de fricção das mãos e antebraço com sabonete líquido contendo clorexidina a 2%. MATERIAIS E MÉTODOS: foram analisadas amostras das pontas dos dedos polegar e indicador, palma da mão e antebraço, de 40 alunos do curso de Odontologia da UNIFRA. A primeira degermação realizada foi com a escova impregnada com clorexidina a 2%, e, sete dias após, os mesmos participantes degermaram as mãos com sabonete contendo clorexidina a 2%. As amostras foram coletadas em placas contendo meio Ágar Base Sangue, identificadas e levadas ao laboratório de microbiologia. RESULTADOS:os mostraram que o método de fricção com sabonete contendo clorexidina a 2% apresentou melhores resultados. CONCLUSÃO: a higienização das mãos pelo método de fricção com sabonete contendo clorexidina a 2% foi mais eficaz quando comparada à realizada com escova impregnada com clorexidina a 2%, sugerindo um método de preparo pré-cirúrgico das mãos mais rápido, eficaz e menos oneroso... (AU)

ABSTRACT Hand washing reduces the amount of skin bacteria, thus contributing to reducing infection rates. There are several techniques for hand washing and the health professional should choose the most appropriate one. OBJECTIVES: This study evaluated the effectiveness of surgical hands and forearms washing made with brush impregnated with 2% chlorhexidine, compared with the friction method of hands and forearms with liquid soap containing 2% chlorhexidine. MATERIALS AND METHODS: We analyzed tip of the thumb and index finger, palm and forearm from 40 students of Dentistry from UNIFRA. The first protocol antisepsis was performed with a brush impregnated with 2% chlorhexidine, and seven days later, the same participants washed their hands with soap containing 2% chlorhexidine. The samples were collected in plates containing Blood Agar Base, identified and taken to the microbiology laboratory. RESULTS:The method of rubbing the soap containing 2% chlorhexidine performed better. CONCLUSION: Hand hygiene by friction method with soap containing 2% chlorhexidine is more effective than the one performed with brush impregnated with 2% chlorhexidine, suggesting a faster, effective and less costly presurgical hand preparation... (AU)

Preserved Filamentous Microbial Biosignatures in the Brick Flat Gossan, Iron Mountain, California.

A variety of actively precipitating mineral environments preserve morphological evidence of microbial biosignatures. One such environment with preserved microbial biosignatures is the oxidized portion of a massive sulfide deposit, or gossan, such as that at Iron Mountain, California. This gossan may serve as a mineralogical analogue to some ancient martian environments due to the presence of oxidized iron and sulfate species, and minerals that only form in acidic aqueous conditions, in both environments. Evaluating the potential biogenicity of cryptic textures in such martian gossans requires an understanding of how microbial textures form biosignatures on Earth. The iron-oxide-dominated composition and morphology of terrestrial, nonbranching filamentous microbial biosignatures may be distinctive of the underlying formation and preservation processes. The Iron Mountain gossan consists primarily of ferric oxide (hematite), hydrous ferric oxide (HFO, predominantly goethite), and jarosite group minerals, categorized into in situ gossan, and remobilized iron deposits. We interpret HFO filaments, found in both gossan types, as HFO-mineralized microbial filaments based in part on (1) the presence of preserved central filament lumina in smooth HFO mineral filaments that are likely molds of microbial filaments, (2) mineral filament formation in actively precipitating iron-oxide environments, (3) high degrees of mineral filament bending consistent with a flexible microbial filament template, and (4) the presence of bare microbial filaments on gossan rocks. Individual HFO filaments are below the resolution of the Mars Curiosity and Mars 2020 rover cameras, but sinuous filaments forming macroscopic matlike textures are resolvable. If present on Mars, available cameras may resolve these features identified as similar to terrestrial HFO filaments and allow subsequent evaluation for their biogenicity by synthesizing geochemical, mineralogical, and morphological analyses. Sinuous biogenic filaments could be preserved on Mars in an iron-rich environment analogous to Iron Mountain, with the Pahrump Hills region and Hematite Ridge in Gale Crater as tentative possibilities.

Prelude to oral microbes and chronic diseases: past, present and future.

Associations between oral and systemic health are ancient. Oral opportunistic bacteria, particularly, Porphyromonas gingivalis and Fusobacterium nucleatum, have recently been deviated from their traditional roles as periodontal pathogens and arguably ascended to central players based on their participations in complex co-dependent mechanisms of diverse systemic chronic diseases risk and pathogenesis, including cancers, rheumatoid-arthritis, and diabetes.

Avaliação do crescimento de Salmonella enterica em fórmulas lácteas infantis sob diferentes condições de preparo e armazenamento / Evaluation of the growth of Salmonella enterica in infant milk formulas under different preparation and storage conditions

Salmonella enterica é um dos mais importantes patógenos associados a fórmulas lácteas infantis (FLI). Neste trabalho, foi avaliada a sobrevivência e crescimento de uma estirpe padrão de Salmonella enterica sorotipo Typhi em duas FLI reconstituídas (F1 e F2) sob diferentes condições de preparo e armazenamento similares às utilizadas em lactários hospitalares. Para ambas as FLI inoculadas e incubadas à temperatura ambiente, observou-se um aumento de 3,3 log na população de S. enterica logo nas primeiras 24 horas de incubação e um aumento superior a 4,5 log ao término de 72 horas. A 4ºC, nas primeiras 48 h de incubação, houve leve aumento populacional (< 1,0 log) e, após 72 horas, o crescimento foi similar ao observado sob temperatura ambiente. Em relação ao aquecimento em banho-maria, verificou-se que a 60ºC/ 5 min houve uma redução de um pouco mais de 1 log UFC/ml, entretanto, a 60ºC/ 10 min, a queda observada foi de 2,8 log em F1 e de 2,3 log em F2. Já a 70ºC/ 5 min, ocorreu redução de cerca de 3 log UFC/ml para F1 e F2, enquanto que por 10 min, essa redução foi cerca de 1 log maior. O aquecimento em forno de micro-ondas mostrou ser a forma mais rápida e eficiente de redução da população de Salmonella nas FLI, uma vez que não foi detectada contagem celular após nenhum dos tratamentos utilizados. Os resultados sugerem que FLI contaminadas durante a etapa de preparo podem apresentar um crescimento bacteriano mesmo sob temperatura de refrigeração se mantidos por tempo prolongado e que determinados métodos de tratamento térmico não são suficientes para inibição completa de S. enterica.

Salmonella enterica is one of the most important pathogens associated with infant milk formulas (IMFs). In this study, the survival and growth of an S. enterica serovar Typhi strain in two reconstituted IMFs (F1 and F2) under different conditions of preparation and storage, similar to those used in hospital lactaries, was evaluated. For both IMFs inoculated at room temperature, there was 3.3 log increase in the population of S. enterica by the first 24 h of incubation and > 4.5 log increase at the end of 72 h. At 4ºC, in the first 48 h of incubation, there was a slight increase in population (< 1.0 log) and after 72 h, growth was similar to that observed at room temperature. A heated water bath was used to test the effect of thermal treatment methods on bacterial viability. At 60ºC for 5 min, there was a reduction of slightly more than 1 log CFU/mL; however, at 60ºC for 10 min, the observed decrease was 2.8 log for F1 and 2.3 log for F2. At 70ºC for 5 min, there was a reduction of approximately 3 log CFU/ml for both IMFs and for 10 min, this reduction was approximately 1 log higher. Heating in a microwave oven was the most efficient way of reducing populations of Salmonella in the IMFs, as bacterial cell counts were not detected after any of the treatments used. Our results suggest that IMF contamination during the preparation step may support bacterial growth even under refrigeration if kept for a prolonged time and that some thermal treatment methods are not sufficient for the complete inhibition of S. enterica.

Physico-chemical and microbiological changes in commercial tilapia (Oreochromis niloticus) during cold storage / Cambios fisico-químicos y microbiológicos en tilapia comercial (Oreochromis niloticus) durante almacenamiento refrigerado

Background: The microbiological and chemical processes are the main responsible for deterioration of fresh fish. Therefore, it is essential to avoid these processes by applying good manufacturing practices during fish handling, distribution and storage. Objective: The aim of this paper was to evaluate the physico-chemical and microbial changes in commercial tilapia (Oreochromis niloticus) during cold storage in order to establish the shelf life since its arrival at the supermarket. Methods: 27 aquacultured tilapia specimens were analyzed at 0, 2, 4, and 7 days of storage at 4ºC. Measurements of texture, color, water holding capacity, total volatile basic nitrogen (TVB-N), thiobarbituric acid index, ATP-related compounds, as well as microbial analyses were carried out. Results: The TVB-N content was high at the beginning of the study, remaining stable during the storage. Lipid oxidation of samples was minimum, so this process did not contribute to the fish spoilage. It was observed the breakdown of inosine-5'- monophosphate (IMP) into Ino (inosine), and Ino into Hx (hypoxantine). The texture parameters and colour underwent changes as a consequence of the fish spoilage. Low microbial counts were observed at day 0, but Enterobacteriaceae and mesophilic counts gradually increased throughout storage. Conclusions: The K1 -value showed the progressive spoilage of the fish during the cold storage. The decrease of hardness and firmness confirmed the loss of quality throughout the time of study. The low microbial counts at the beginning of the study demonstrated the good quality of the tilapia; however, the increase of the mesophilic counts at the end of the studied period showed that tilapia was not fit for human consumption at day 7.

Antecedentes: Los procesos microbiológicos y químicos son los principales responsables del deterioro del pescado fresco. Por tanto, es esencial evitar estos procesos aplicando buenas prácticas de fabricación durante la manipulación, distribución y almacenamiento del pescado. Objetivo: El objetivo de este trabajo fue evaluar los cambios físico-químicos y microbiológicos en tilapia comercial (Oreochromis niloticus) durante el almacenamiento refrigerado con el fin de establecer la vida útil desde su llegada al supermercado. Métodos: 27 especímenes de tilapia fueron analizados a día 0, 2, 4 y 7 de almacenamiento a 4 ºC. Se llevaron a cabo medidas de textura, color, capacidad de retención de agua, nitrógeno básico volátil total (N-BVT), índice del ácido tiobarbitúrico, compuestos relacionados con el ATP, así como análisis microbianos. Resultados: El contenido en N-BVT fue alto al principio del estudio, siendo estable durante el almacenamiento. La oxidación lipídica de las muestras fue mínima, por lo que este proceso no contribuyó al deterioro del pescado. Se observó la degradación de inosina-5'- monofosfato (IMP) a Ino (inosina), y de Ino a Hx (hipoxantina). Los parámetros de textura y color sufrieron cambios como consecuencia del deterioro del pescado. Se observaron bajos recuentos microbianos a día 0, pero los recuentos de Enterobacteriaceae y de mesófilos aumentaron gradualmente durante el almacenamiento. Conclusiones: El valor K1 mostró el deterioro progresivo del pescado durante el almacenamiento en refrigeración. La disminución de dureza y firmeza confirmó la pérdida de calidad a lo largo del tiempo de estudio. Los bajos recuentos microbianos al principio del estudio demostraron la buena calidad de la tilapia; sin embargo, el aumento de los recuentos de mesófilos al final del periodo estudiado mostraron que la tilapia no era adecuada para el consumo humado a día 7.