Abstract Pseudomonas fluorescens is known to have the ability to adhere and produce biofilm. The formation of biofilms is enhanced by cellular motility, particularly when mediated by flagella. Biofilm formed on surfaces such as those used for food production act as points of contamination, releasing pathogenic or deteriorating microorganisms and compromising the quality of products. We assessed two strains of Pseudomonas fluorescens PL5.4 and PL7.1, sampled from raw, chilled, buffalo milk, which was obtained from a dairy farm. Twitching and swarming motility assays were performed, in addition to the biofilm production evaluations at a temperature of 7 °C. Regarding the motility assays, only the PL5.4 strain scored positive for the swarming assay. On microplates, both strains presented themselves as strong biofilm producers at 7 °C. The PL5.4 strain was also able to form biofilm on a stainless steel structure and maintain this structure for up to 72 hours at refrigeration. The Pseudomonas fluorescens PL5.4 isolate was identified on the basis of a 99% sequence identity with Pseudomonas fluorescens A506, a strain used as a biocontrol in agriculture. Biofilm-forming bacteria, when adapted to low temperatures, become a constant source of contamination, damaging the production, quality, safety and shelf-life of products.

Abstract To evaluate the performance of MALDI-TOF MS system as a tool for identification and differentiation of Burkholderia cenocepacia from other species of Burkholderia cepacia complex (Bcc). Fifty-three suggestive colonies were submitted to the MALDI-TOF Microflex LT 4.0® (Bruker Daltonik, Bremen, Germany) system for identification. We compared two protocols of protein extraction: (A) Direct Method and (B) Tube Extraction. In parallel, all isolates were subjected to molecular diagnosis (primers for recA gene) to identify species belonging to Bcc and to differentiate B. cenocepacia in genomovar IIIA or IIIB. MALDI-TOF was able to identify all isolates to the genus level and 94.3% (50/53) to species using both methods. The MALDI-TOF system was able to identify 38 out of the 40 isolates identified as B. cenocepacia by molecular techniques. In conclusion, MALDI-TOF Microflex LT 4.0® is a feasible technique and presents a low cost of reagents; it can be used for the reliable differentiation of B. cenocepacia from other species of Bcc.

Abstract INTRODUCTION: The main laboratory test for the diagnosis of coronavirus disease 2019 (COVID-19) is the reverse transcription real-time polymerase chain reaction (RT-qPCR). However, RT-qPCR is expensive because of the number of tests required. This study aimed to evaluate an alternative to the RT-qPCR approach for the detection of sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is half of the total volume currently recommended by the US Centers for Disease Control and Prevention. METHODS: The analytical limit of detection (LoD) and the reaction efficiency using half volumes of the RT-qPCR assay were evaluated for the N1 and N2 regions using a synthetic control RNA. A panel of 76 SARS-CoV-2-positive and 26 SARS-CoV-2-negative clinical samples was evaluated to establish clinical sensitivity and specificity. RESULTS: The RT-qPCR assay efficiency was 105% for the half and standard reactions considering the N2 target and 84% (standard) and 101% (half) for N1. The RT-qPCR half-reaction LoD for N1 and N2 were 20 and 80 copies/µL, respectively. The clinical sensitivity and specificity were 100%. The half reaction presented a decrease of up to 5.5 cycle thresholds compared with standard RT-qPCR. CONCLUSIONS: The use of the RT-qPCR half-reaction proved feasible and economic for the detection of SARS-CoV-2 RNA.

Abstract INTRODUCTION: Considering the persistent positivity on RT-qPCR tests, the results of SARS-CoV-2 were monitored to evaluate the viral RNA shedding period. METHODS: Between March and June 2020, the sequential results of 29 healthcare workers’ were monitored using RT-qPCR. RESULTS: More than 50% of the individuals remained RT-qPCR positive after 14 days. Furthermore, this is the first study to describe positive RT-qPCR for SARS-CoV-2 in a healthcare worker with mild symptoms 95 days after the first positive test. CONCLUSIONS: Sequential RT-qPCR results were heterogeneous, and the viral RNA shedding period is unique for each person.

As doenças de veiculação alimentar representam um problema de ordem global. No Brasil, o patógeno mais prevalente em surtos de intoxicação alimentar é a Salmonella sp. (14,4%), seguido pelo Staphylococcus aureus (7,7%), Escherichia coli (6,5%) e Bacillus cereus (3,1%). Com o objetivo de realizar uma análise regional detalhada da intoxicação alimentar, examinamos os relatórios de 253 surtos, notificados à equipe de Vigilância de Alimentos da Coordenadoria Geral de Vigilância em Saúde de Porto Alegre, Rio Grande do Sul, entre 2003 e 2013. Ao contrário do que é notificado no Brasil, em Porto Alegre, identificamos como principal agente etiológico, o Bacillus cereus (32,2%) e de acordo com os sintomas dos pacientes, a maioria dos casos esteve associada à produção de enterotoxina. A maioria dos surtos foram associados à ingestão de alimentos que continham cereais ou molhos mantidos à temperatura ambiente durante o armazenamento ou preparação. O uso compulsório de ovos pasteurizados em Porto Alegre pode explicar a relativa escassez de surtos de Salmonella sp. no município.

Foodborne diseases are a global concern. In Brazil, the most prevalent pathogen found in foodborne outbreaks is Salmonella sp. (14.4%), followed by Staphylococcus aureus (7.7%), Escherichia coli (6.5%), and Bacillus cereus (3.1%). With the aim to perform a regional detailed analysis of foodborne intoxication, we analyzed 253 outbreaks’ profile reports to Food Surveillance team of the General Secretariat of Health Surveillance of Porto Alegre, Rio Grande do Sul State, between 2003 and 2013. In contrast to what was most notified in Brazil, in Porto Alegre the main outbreak agent identified was Bacillus cereus (32.2%) and, based on the patient symptoms, most cases were linked to enterotoxin production. The majority of the outbreaks were linked to the ingestion of food containing cereals or sauces poorly kept at environment temperature during the stock or preparation. We believe that, due to the compulsory use of pasteurized eggs in our city, Salmonella sp. outbreaks are less important here.

Las enfermedades transmitidas a través de la comida son una preocupación de carácter global. En Brasil, el patógeno encontrado de forma más prevalente en los brotes de epidemias alimentarias es la Salmonella sp. (14,4%), seguida por el Staphylococcus aureus (7,7%), Escherichia coli (6,5%), y el Bacillus cereus (3,1%). Con el fin de realizar un análisis regional detallado de los brotes de infecciones alimentarias, analizamos el perfil de 253 brotes, registrados por el servicio de Vigilancia Alimentaria de la Secretaría General de Vigilancia en Salud de Porto Alegre, Rio Grande do Sul, entre 2003 y 2013. En contraste con lo que fue más notificado en Brasil, en Porto Alegre el principal agente causante de brotes fue identificado como el Bacillus cereus (32.2%) y, basado en los síntomas del paciente, la mayoría de los casos estaban relacionados con la producción de la enterotoxina. Muchos de los brotes estaban relacionados con la ingesta de comida que contenía cereales o salsas mal conservadas a temperatura ambiente durante el almacenaje o la preparación. Creemos que, debido a la utilización obligatoria de huevos pasteurizados en nuestra ciudad, los brotes de Salmonella sp. son menos relevantes aquí.

As doenças de veiculação alimentar representam um problema de ordem global. No Brasil, o patógeno mais prevalente em surtos de intoxicação alimentar é a Salmonella sp. (14,4%), seguido pelo Staphylococcus aureus (7,7%), Escherichia coli (6,5%) e Bacillus cereus (3,1%). Com o objetivo de realizar uma análise regional detalhada da intoxicação alimentar, examinamos os relatórios de 253 surtos, notificados à equipe de Vigilância de Alimentos da Coordenadoria Geral de Vigilância em Saúde de Porto Alegre, Rio Grande do Sul, entre 2003 e 2013. Ao contrário do que é notificado no Brasil, em Porto Alegre, identificamos como principal agente etiológico, o Bacillus cereus (32,2%) e de acordo com os sintomas dos pacientes, a maioria dos casos esteve associada à produção de enterotoxina. A maioria dos surtos foram associados à ingestão de alimentos que continham cereais ou molhos mantidos à temperatura ambiente durante o armazenamento ou preparação. O uso compulsório de ovos pasteurizados em Porto Alegre pode explicar a relativa escassez de surtos de Salmonella sp. no município.

Foodborne diseases are a global concern. In Brazil, the most prevalent pathogen found in foodborne outbreaks is Salmonella sp. (14.4%), followed by Staphylococcus aureus (7.7%), Escherichia coli (6.5%), and Bacillus cereus (3.1%). With the aim to perform a regional detailed analysis of foodborne intoxication, we analyzed 253 outbreaks’ profile reports to Food Surveillance team of the General Secretariat of Health Surveillance of Porto Alegre, Rio Grande do Sul State, between 2003 and 2013. In contrast to what was most notified in Brazil, in Porto Alegre the main outbreak agent identified was Bacillus cereus (32.2%) and, based on the patient symptoms, most cases were linked to enterotoxin production. The majority of the outbreaks were linked to the ingestion of food containing cereals or sauces poorly kept at environment temperature during the stock or preparation. We believe that, due to the compulsory use of pasteurized eggs in our city, Salmonella sp. outbreaks are less important here.

Las enfermedades transmitidas a través de la comida son una preocupación de carácter global. En Brasil, el patógeno encontrado de forma más prevalente en los brotes de epidemias alimentarias es la Salmonella sp. (14,4%), seguida por el Staphylococcus aureus (7,7%), Escherichia coli (6,5%), y el Bacillus cereus (3,1%). Con el fin de realizar un análisis regional detallado de los brotes de infecciones alimentarias, analizamos el perfil de 253 brotes, registrados por el servicio de Vigilancia Alimentaria de la Secretaría General de Vigilancia en Salud de Porto Alegre, Rio Grande do Sul, entre 2003 y 2013. En contraste con lo que fue más notificado en Brasil, en Porto Alegre el principal agente causante de brotes fue identificado como el Bacillus cereus (32.2%) y, basado en los síntomas del paciente, la mayoría de los casos estaban relacionados con la producción de la enterotoxina. Muchos de los brotes estaban relacionados con la ingesta de comida que contenía cereales o salsas mal conservadas a temperatura ambiente durante el almacenaje o la preparación. Creemos que, debido a la utilización obligatoria de huevos pasteurizados en nuestra ciudad, los brotes de Salmonella sp. son menos relevantes aquí.

O objetivo do presente estudo foi caracterizar bacteriocinas produzidas por 70 cepas de Enterococcus mundtii. Estas foram caracterizadas quanto a sua atividade antimicrobiana, sensibilidade ao aquecimento, pH, armazenamento e enzimas proteolíticas. Foi também determinada sua cinética de produção e peso molecular. Entre as 70 cepas analisadas, quatro apresentaram atividade antibiótica contra Listeria innocua, L. monocytogenes, Lactobacillus plantarum, e Salmonella Enteritidis. Esta atividade foi mantida em temperaturas até 121ºC por 20 minutos, e sob condições de pH entre 2,0 e 10,0. A atividade antimicrobiana foi mantida nos testes de armazenamento a -20°C, por 60 dias. A cinética de produção revelou picos de atividade de 1600 AU/mL durante a fase logarítmica de crescimento e o peso molecular foi de aproximadamente 3,0 kDa. A caracterização dos produtos com atividade antimicrobiana revelaram suas naturezas protéicas, cinéticas de metabólito primário e peso molecular semelhante aos das enterocinas já purificadas.

The aim of this study was to characterize bacteriocins produced by 70 strains of Enterococcus mundtii.Four strains exhibited antibiotic activity towards Listeria innocua, L. monocytogenes, Lactobacillus plantarum, and Salmonella Enteritidis. They remained active under temperatures of up to 121ºC for 20 min, and under pH treatments that varied from 2.0 to 10.0. Antimicrobial activity was maintained during the storage test for 60 days under freezing. The kinetics of production revealed the peak activity of 1600 AU /mL during the logarithmic growth phase and the molecular weight found was approximately 3.0 kDa. The characterization of the products with antimicrobial activity indicated their proteic nature, presenting a typical kinetics of primary metabolite and a molecular weight similar to many purified enterocins.