In Silico Detection of Integrons and Their Relationship with Resistance Phenotype of Salmonella Isolates from a Brazilian Pork Production Chain.

The pork production chain is an important reservoir of antimicrobial resistant bacteria. This study identified and characterized integrons in Salmonella isolates from a Brazilian pork production chain and associate them with their antibiotic resistance pattern. A total of 41 whole-genome sequencing data of nontyphoidal Salmonella were analyzed using PlasmidSPAdes and IntegronFinder software. Nine isolates (21.9%) had some integrons identified (complete and/or incomplete). Six complete class 1 integrons were found, with streptomycin resistance genes (aadA1, aadA2) alone or downstream of a trimethoprim resistance gene (dfrA1, dfrA12), and some also containing resistance genes for sulfonamides (sul1, sul3) and chloramphenicol (cmlA1). Class 2 integron was detected in only one isolate, containing dfrA1-sat2-aadA1 gene cassettes. Five isolates harbored CALINs-clusters attC but lacking integrases-with antimicrobial resistance genes typically found in integron structures. In all, integrons were observed among four serotypes: Derby, Bredeney, Panama, and monophasic var. Typhimurium I 4,[5],12:i:-. The association of integrons with antibiotic resistance phenotype showed that these elements were predominantly identified in multidrug resistance isolates, and six of the seven gentamicin-resistant isolates had integrons. So, surveillance of integrons in Salmonella should be performed to identify the potential for the spread of antimicrobial resistance genes among bacteria.

Pseudomonas carnis isolated from blue discolored fresh cheese and insights into the phylogeny.

Most Pseudomonas spp. are responsible for spoilage in refrigerated foods such as alteration in flavor, texture and appearance. Samples of Minas Frescal cheese with blue discoloration were analysed and contained a high Pseudomonas concentration (7.72 ± 0.36 log CFU/g). Out of the 26 Pseudomonas isolates that were analyzed in our study, 19 demonstrated the capability of producing a diffusible dark pigment. Thus, a pigment-producing isolate (C020) was selected by rep-PCR fingerprinting and subsequently subjected to whole-genome sequencing. The draft genome assembled comprises 42 contigs totaling 6,366,75 bp with an average G + C content of 59.97%, and the species prediction performed by TYGS server, based on the draft genome sequence, identified the C020 as Pseudomonas carnis. In order to investigate the phylogenetic relationships of this isolate with strains already identified of this species, we performed an analysis based on whole-genomic sequences. First, an analysis of all P. carnis genomes deposited in GenBank to date shows that 11% (4/37) are misidentified, and belong to the Pseudomonas paracarnis species. A comparative analysis based on phylogenomic analysis has showed that there is no evolutionary relationship between P. carnis strains carrying second copies of trp genes related to blue discoloration (trpABCDF). This finding reinforces the assertion that these genes are contained in a mobile genetic element. However, it is worth noting that all strains carrying these secondary gene copies have exclusively been isolated from food sources. This observation provides valuable insights into the potential origins and dispersion dynamics of this genetic trait within the species.

Genomic Analyses of Weissella cibaria W25, a Potential Bacteriocin-Producing Strain Isolated from Pasture in Campos das Vertentes, Minas Gerais, Brazil.

Weissella is a genus containing Gram-positive, heterofermentative bacteria belonging to the lactic acid bacteria (LAB) group. These bacteria are endowed with promising technological and antimicrobial attributes. Weissella cibaria W25 was isolated from a dairy environment where raw milk cheeses are produced. Therefore, we sequenced and assembled the W25 draft genome sequence, which consists of 41 contigs totaling ~2.4 Mbp, with a G + C content of 45.04%. Then we carried out a comprehensive comparative genomic analysis with W. cibaria 110, known to produce the weissellicin 110 bacteriocin, and four other non-bacteriocin-producing W. cibaria strains.

Influence of Emulsifying Salts on the Growth of Bacillus thuringiensis CFBP 3476 and Clostridium perfringens ATCC 13124 in Processed Cheese.

Processed cheese is a dairy product with multiple end-use applications, where emulsifying salts play a fundamental role in physicochemical changes during production. Moreover, some of these salts may be a strategy to control spoilage and pathogenic microorganisms, contributing to safety and shelf life extension. This study aimed to evaluate the in vitro inhibitory activity of two emulsifying salts (ESSP = short polyP and BSLP = long polyP) against Bacillus thuringiensis CFBP 3476 and Clostridium perfringens ATCC 13124, and to compare the in situ effects of two emulsifying salts treatments (T1 = 1.5% ESSP and T2 = 1.0% ESSP + 0.5% BSLP) in processed cheeses obtained by two different methods (laboratory- and pilot-scales), during 45-day storage at 6 °C. C. perfringens ATCC 13124 growth was not affected in vitro or in situ (p > 0.05), but both of the treatments reduced B. thuringiensis CFBP 4376 counts in the tested condition. Counts of the treatments with B. thuringiensis CFBP 3476 presented a higher and faster reduction in cheeses produced by the laboratory-scale method (1.6 log cfu/g) when compared to the pilot-scale method (1.8 log cfu/g) (p < 0.05). For the first time, the inhibitory effect of emulsifying salts in processed cheeses obtained by two different methods was confirmed, and changes promoted by laboratory-scale equipment influenced important interactions between the processed cheese matrix and emulsifying salts, resulting in B. thuringiensis CFBP 4376 growth reduction.

Diversity of Filamentous Fungi Associated with Dairy Processing Environments and Spoiled Products in Brazil.

Few studies have investigated the diversity of spoilage fungi from the dairy production chain in Brazil, despite their importance as spoilage microorganisms. In the present study, 109 filamentous fungi were isolated from various spoiled dairy products and dairy production environments. The isolates were identified through sequencing of the internal transcribed spacer (ITS) region. In spoiled products, Penicillium and Cladosporium were the most frequent genera of filamentous fungi and were also present in the dairy environment, indicating that they may represent a primary source of contamination. For dairy production environments, the most frequent genera were Cladosporium, Penicillium, Aspergillus, and Nigrospora. Four species (Hypoxylon griseobrunneum, Rhinocladiella similis, Coniochaeta rosae, and Paecilomyces maximus) were identified for the first time in dairy products or in dairy production environment. Phytopathogenic genera were also detected, such as Montagnula, Clonostachys, and Riopa. One species isolated from the dairy production environment is classified as the pathogenic fungi, R. similis. Regarding the phylogeny, 14 different families were observed and most of the fungi belong to the Ascomycota phylum. The understanding of fungal biodiversity in dairy products and environment can support the development of conservation strategies to control food spoilage. This includes the suitable use of preservatives in dairy products, as well as the application of specific cleaning and sanitizing protocols designed for a specific group of target microorganisms.

Qualidade microbiológica de açaí comercializado na cidade de Guanambi-BA / Microbiological quality of açaí commercialized in the city of Guanambi-BA

Frutas são perecíveis e deterioram rapidamente, devido à sua variedade de nutrientes e a contaminação biológica. No entanto, quando se faz um processamento e congelamento de polpa de fruta há redução de perdas, traz praticidade, propicia a comercialização e conserva as características químicas e sensoriais da fruta in natura, como as polpas de açaí, que na maioria das vezes são comercializadas congeladas. Entretanto, à quebra da cadeia de frio durante a distribuição, compromete a qualidade da polpa de açaí, estando a contaminação desta polpa associada à baixa qualidade higiênico-sanitária durante a manipulação e o processamento da matéria-prima ou à uma contaminação dos equipamentos. Deste modo, o objetivo desse trabalho foi avaliar a qualidade microbiológica de açaí comercializado na cidade de Guanambi-BA. O açaí foi coletado de cinco estabelecimento do município, sendo as amostras coletadas com três repetições, uma a cada 7 dias. As polpas foram submetidas as análises microbiológicas de fungos filamentosos e leveduras, coliformes totais e termotolerantes. A legislação brasileira não apresenta um padrão para coliformes totais, mas estipula limite para coliformes termotolerantes e fungos filamentosos. De acordo com os resultados obtidos, o açaí de todos os pontos de coleta se apresentaram acima dos limites estabelecidos e, portanto, fora do padrão estipulado. Adoção e melhorias de medidas sanitárias, não só na comercialização do produto, mas desde a colheita dos frutos, são fundamentais para melhorias da condição microbiológica da comercialização das polpas de açaí.