Characterization of Lactococcus strains isolated from artisanal Oaxaca cheese

Lactococci strains obtained from raw-milk Oaxaca cheese through its production process in two factories from the Tulancingo Valley, Mexico, were isolated and characterized. A total of 120 colonies were selected from the growth in M17 and MRS agars. Twenty were identified as lactococci strains, all Lactococcus lactis, and were characterized by molecular and phenotypic methods including carbohydrate use, enzymatic profile, acidifying capacity, and antibiotic and phage resistance. High phenotypic diversity was observed and confirmed among the Lactococcus lactis strains by rep-PCR fingerprints. Fifty percent of the strains were resistant to streptomycin and 35% to erythromycin. Nine isolates were considered as fast acidifying strains. The predominant volatile compounds produced were 3-methylbutanol, 3-methylbutanal and butane-2,3-dione. A selection of strains isolated in this study has shown satisfactory characteristics to be used as potential starters for the industrial production of Oaxaca cheese.Peer reviewe

Bioimpedance vector analysis and conventional bioimpedance to assess body composition in older adults with dementia

Producción CientíficaAlthough dementia and nutritional status have been shown to be strongly associated, differences in body composition (BC) among older people with dementia have not yet been firmly established. The aim of this study was to assess BC through conventional and vector bioimpedance analysis (BIA and BIVA, respectively) in a sample of institutionalized older men with and without dementia, in order to detect dementia-related BC changes.Forty-one institutionalized men ages ≥65 y (23 without dementia [CG] and 18 with dementia [DG]) were measured with BIA and interpreted with BIVA and predictive equations.Age (74.4 and 75.7 y) and body mass index (22.5 and 23.6 kg/m 2 ) were similar for DG and CG, respectively. Resistance and ratio of resistance to height did not differ significantly between the two groups. Reactance and ratio of reactance to height were 21.2% and 20.4% lower in DG than in CG. Phase angle was significantly lower in DG (mean = 4.0; 95% confidence interval [CI], 3.6°–4.3°) than in CG (mean = 4.7; 95% CI, 4.3°–5.1°). Mean fat mass index (6 and 7 kg/m 2 ), and mean fat-free mass index (16.4 and 16.6 kg/m 2 ) were similar in both groups. BIVA showed a significant downward migration of the ellipse in DG with respect to CG (T 2 = 15.1; P < 0.01).Conventional BIA showed no significant differences in BC between DG and CG, although reactance and ratio of reactance to height were about 21% lower in DG. Nevertheless, a body cell mass depletion and an increase in the ratio of extracellular to intracellular water were identified in DG using BIVA. BIVA reflects dementia-related changes in BC better than BI

Staphylococcal-produced bacteriocins and antimicrobial peptides: their potential as alternative treatments for Staphylococcus aureus infections

Staphylococcus aureus is an important pathogen of both humans and animals, implicated in a wide range of infections. The emergence of antibiotic resistance has resulted in S. aureus strains that are resistant to almost all available antibiotics, making treatment a clinical challenge. Development of novel antimicrobial approaches is now a priority worldwide. Bacteria produce a range of antimicrobial peptides; the most diverse of these being bacteriocins. Bacteriocins are ribosomally synthesised peptides, displaying potent antimicrobial activity usually against bacteria phylogenetically related to the producer strain. Several bacteriocins have been isolated from commensal coagulase-negative staphylococci, many of which display inhibitory activity against S. aureus in vitro and in vivo. The ability of these bacteriocins to target biofilm formation and their novel mechanisms of action with efficacy against antibiotic-resistant bacteria make them strong candidates as novel therapeutic antimicrobials. The use of genome-mining tools will help to advance identification and classification of bacteriocins. This review discusses the staphylococcal-derived antimicrobial peptides displaying promise as novel treatments for S. aureus infections

REVIEW : PENGGUNAAN STRAIN BAKTERI ASAM LAKTAT PADA FERMENTASI VEGETABLE JUICES. REVIEW : USE OF LACTID ACID BACTERIA STRAIN IN FERMENTED VEGETABLE JUICES

Bakteri asam laktat termasuk mikroorganisme yang aman jika ditambahkan dalam pangan karena tidak menghasilkan toksin, atau dikenal sebagai mikroorganisme Generally Recognized As Safe (GRAS) yaitu mikrorganisme yang tidak beresiko terhadap kesehatan, bahkan beberapa jenis bakteri tersebut berguna bagi kesehatan. Strain BAL merupakan bakteri asam laktat yang didapat dari beberapa sumber isolasi seperti bahan pangan untuk diidentifikasi sifat probiotiknya sehingga bermanfaat untuk kesehatan Beberapa syarat utama agar strain BAL dapat dikategorikan probiotik adalah resistensi terhadap beberapa antbiotik, tidak bersifat patogen, toleran terhadap asam lambung dan garam empedu, dan memiliki tingkat toleransi yang tinggi pada kondisi usus. Vegetables Juice dalam review ini terdiri atas beberapa jenis yaitu jus tomat, jus wortel, jus timun, dan jus kubis yang merupakan minuman probiotik secara fermentasi menggunakan strain BAL. Tujuan dari review ini untuk mengetahui berbagai macam strain dapat dimanfaatkan dan mengetahui pengaruh penggunaan berbagai macam strain BAL pada vegetable juice terutama untuk kesehatan tubuh. Metode yang digunakan adalah dengan mengikhthisarkan data dan informasi dari berbagai pustaka yang terkualifikasi dalam kriteria inklusi yang telah ditetapkan, seperti relevansi dengan topik yang diulas, terkualifikasi dalam SJR (www.scimagojr.com) /SINTA (www.sinta.ristekbrin.go.id), dan kemudian disajikan dalam paragraf dan disertai tabel atau gambar. Keseluruhan literatur jurnal yang digunakan berbasis in-vitro study,in-vivo study, human study, maupun review. Faktor yang mempengaruhi pertumbuhan BAL adalah jenis BAL, dosis penambahan kosentrasi pada substrat, dan interaksi substrat dengan BAL. Strain BAL memiliki spesifikasi yang berbeda-beda dalam memfermentasi vegetables juice karena bergantung pada suhu, waktu, kultur, produk yang difermentasi, tingkat keasaman, serta situasi dan kondisi saat difermentasi. Beberapa pustaka yang ditinjau, penggunaan vegetables juice sebagai substrat atau prebiotik menunjukan mekanisme sinbiotik yang bersifat mutualisme. Penyerapan nutrisi yang dilakukan oleh strain BAL pada substrat menyebabkan viabilitas atau jumlah strain BAL meningkat seiring berjalannya lama fermentasi. Hal ini ditunjukan dengan menurunnya kadar gula dan meningkatnya tingkat keasaman pada jus. Strain BAL menghasilkan bakteriosin yang merupakan senyawa terdiri peptida yang mengandung sekitar 30-60 asam amino merupakan metabolit sekunder yang berfungsi untuk pertahanan diri dari mikroorganisme yang mengancam sekaligus untuk menghambat pertumbuhan bakteri patogen terutama pada proses fermentasi. Proses fermentasi menggunakan strain BAL pada vegetables juice menyebabkan perubahan fisikokimiawi seperti menurunnya nilai pH, meningkatnya presentase tingkat keasaman, menurunnya kadar gula, meningkatnya viabilitas bakteri asam laktat dan beberapa hal lainnya

Nanoemulsões contendo carvacrol: desenvolvimento, caracterização e aplicação na sanitização de alfaces

Os compostos antimicrobianos naturais, como os ácidos orgânicos e os óleos essenciais, têm demonstrado ser promissores na sanitização de vegetais visando a segurança destes alimentos. Nanoemulsões podem aumentar a estabilidade e permitir a liberação controlada destes compostos, porém se tem pouco conhecimento sobre seus efeitos na sanitização de vegetais. Diante disso, foi realizada uma revisão bibliográfica utilizando artigos publicados em inglês, entre 2012 a 2022, com o objetivo de identificar fatores que influencia a aplicação de nanoemulsões (NE) antimicrobianas em vegetais. As publicações (17 no total) reportaram que a ação da NE em vegetais frescos depende da composição e dos métodos de produção, bem como da técnica de aplicação sob a superfície vegetal. Posteriormente, neste trabalho, foram desenvolvidas nanoemulsões de carvacrol por ultrassom de ponteira utilizando surfactante natural (saponina - NCS) ou sintético (polisorbato 80 - NCP) com quantidades variáveis de triglicerídeos de cadeira média (TCM): 5,50 mg/mL de TCM (NCP1 e NCS1) e 22,0 mg/mL de TCM (NCP2 e NCS2). Todas as formulações apresentaram diâmetros médios apropriados (de 74,7 nm a 168,2 nm) e alta eficiência de encapsulação do carvacrol (EE) (de 89,5% a 91,5%). As nanoemulsões de carvacrol com saponina (NCS1 e NCS2) demonstraram ter distribuição de gotas adequada (índice de PDI 3 log CFU/g) após a imersão da alface por 15 min a 2×CIB. A NCS1 demonstrou melhor eficácia na redução dos coquetéis bacterianos (> 3 log UFC/g) quando comparada com ácido acético e ácido cítrico (que reduziu 3 log CFU/g) e similares para E. coli (≅ 3 log CFU/g) após a imersão da alface por 15 min. A imersão de alface em NCS1 durante 15 min, para ambas concentrações de carvacrol (CIB e 2×CIB) não teve impacto significativo na cor e na firmeza das amostras. Por outro lado, o tratamento das alfaces com carvacrol não-encapsulado na 2×CIB escureceu e reduziu a firmeza das alfaces tratadas. Consequentemente, a nanoemulsão de carvacrol-saponina (NCS1) provou ser um sanitizante potencial para a alface.Natural antimicrobial compounds, such as organic acids and essential oils, can be promising sanitizers for vegetables. Encapsulation of these compounds in nanoemulsions can increase their stability and allow controlled release of the bioactive compound. However, some factors may influence the antimicrobial activity of nanoemulsions applied on vegetables. For this reason, a review of articles published between 2012 and 2022 was conducted with the aim of investigating the application of antimicrobial nanoemulsions (NE) applied to vegetables. The publications (17 in total) reported that the action of NE on fresh vegetables depends on the composition and production methods, as well as, the technique of NE application on the vegetable surface. Subsequently, in this work, carvacrol nanoemulsions were developed by probe sonication using natural surfactant (saponin - CNS) or synthetic (polysorbate 80 - CNP) with varying amounts of medium-chair triglycerides (MCT): 5.50 mg/mL of MCT (CNP1 and CNS1) and 22.0 mg/mL of TCM (CNP2 and CNS2). All formulations showed appropriate droplet sizes (from 74.7 nm to 168.2 nm) and high encapsulation efficiency of carvacrol (EE) (from 89.5% to 91.5%). Carvacrol nanoemulsion with saponin (CNS1 and CNS2) demonstrated to have adequate droplet distribution (PDI index 3 log CFU/g) after lettuce immersion for 15 min at 2×BIC. The CNS1 demonstrated better efficacy in reducing both tested bacterial cocktails (> 3 log CFU/g) when compared to acetic and citric acids (that reduced 3 log CFU/g) and similar for E. coli (≅ 3 log CFU/g) after immersion of lettuce for 15 min. Immersion of lettuce in CNS1 for 15 min for both concentrations of carvacrol (BIC and 2×BIC) had no significant impact on the color and firmness of the samples. On the other hand, treating lettuce with non-encapsulated carvacrol at 2×BIC darkened and reduced the firmness of the treated lettuce. Consequently, the carvacrol-saponin nanoemulsion (CNS1) proved to be a potential sanitizer for lettuce

Exploiting the healthy microflora to develop new treatments for Staphylococcus pseudintermedius infection in canine atopic dermatitis

Staphylococcus pseudintermedius is a commensal microorganism and opportunistic pathogen, most frequently responsible for causing pyoderma and secondary skin infections in dogs with atopic dermatitis, one of the most common causes for antimicrobial prescriptions in small animal practice. The emergence of methicillin- and multidrug-resistant S. pseudintermedius strains has resulted in some infections being deemed untreatable by many veterinarians. The potential for zoonotic transmission also makes S. pseudintermedius a public health concern; thus, identifying novel antimicrobial treatments for S. pseudintermedius is a priority in human and animal health. Bacteriocins, ribosomally-synthesised peptides, provide an alternative to antibiotics, displaying potent, specific, antimicrobial activity against strains closely related to or sharing the same niche as the producing bacteria. This study explored the skin microbiota of healthy dogs, investigating the prevalence of commensal staphylococci, and bacteriocin production by the species isolated. Staphylococci were isolated from skin swabs of 121 healthy dogs; 166 isolates, belonging to 20 species, including two proposed novel species, were identified. Twelve methicillin-resistant isolates were identified, seven of which were multidrug-resistant, all belonging to coagulase-negative staphylococci species. Thirteen isolates belonging to eight species displayed inhibitory activity against S. pseudintermedius via deferred-antagonism assay. One Staphylococcus devriesei isolate, H14, inhibited ten clinically relevant S. pseudintermedius and two Staphylococcus aureus strains in cell- free supernatant assays, reducing growth by over 70%, including methicillin-resistant strains. Genome-mining identified two novel bacteriocin gene clusters from S. devriesei H14. Nine further novel bacteriocin gene clusters were identified, from S. pseudintermedius, Staphylococcus warneri, Staphylococcus simulans, and Staphylococcus xylosus. These bacteriocins show promise as novel therapies for S. pseudintermedius infections in canine atopic dermatitis