Showing papers by "Gerson Nakazato published in 2017"

Virulence Genes and Antimicrobial Resistance in Escherichia coli from Cheese Made from Unpasteurized Milk in Brazil.

Abstract: Cow raw milk cheese is widely eaten in Brazil. These products may be contaminated with pathogenic bacteria. In this work, we investigated the presence of Escherichia coli in raw milk cheese from different States in Brazil. From 147 “Minas” cheese samples, 28 cheeses were positive for E. coli. Among 39 E. coli isolates of the cheeses, one was positive for eae and negative for bpfA and efa1/lifA using PCR, and so was classified as atypical Enteropathogenic E. coli (aEPEC). Two other isolates were positive for extraintestinal pathogenic E. coli (ExPEC) genes. The aEPEC isolate belongs to serogroup O127 and was classified in A phylogenetic group, and ExPEC isolates were found in O73:H12 (EC-2 strain) and O64474:H8 (EC-9 strain) serotype. This ExPEC belongs to A and C phylogenetic group, respectively. Most of E. coli strains belonged to Clermont phylogenetic groups A (28.2%), C, and E (23.1%). Six strains (15.4%) of E. coli were positive for group B1 and two (5.1%) for B2. E. coli isolates presented a...

Use of nanoparticles as a potential antimicrobial for food packaging

Abstract: Contamination of food by bacteria and fungi can cause severe human infections, particularly in the case of multiresistant microorganisms to conventional antimicrobials. Metallic and polymeric nanoparticles have showed potent antimicrobial properties. Silver metallic nanoparticles showed powerful antimicrobial effect against foodborne bacterial and fungal pathogens. The association of silver nanoparticles with other compounds resulted in synergistic antimicrobial effects. Polymeric nanoparticles, such as alginate and chitosan, also showed antimicrobial activity. These polymeric nanoparticles can act as carriers and donors of different antimicrobial compounds, such as nitric oxide. Silver and polymeric nanoparticles can be used to make fibers, films, gels, sponges, beads, and packaging. The uses of nanoparticles for food industry have been considered as versatile materials for packaging and coating. Our research group demonstrated the antibacterial activity of nanoparticles in combination with therapeutic compounds (eg, phenazine and nitric oxide) against pathogens that can cause foodborne infections. In this scenario, this chapter presents and discusses the recent advances in the use of nanoparticles in food industry as potent antimicrobial agents, and hopes to be a source of inspiration for new developments in this field.

Additive interaction of carbon dots extracted from soluble coffee and biogenic silver nanoparticles against bacteria

Abstract: It is known the presence of carbon dots (CDs) in carbohydrate based foods CDs extracted from coffee grounds and instant coffee was also published CDs from soluble coffee revealed an average size of 44 nm CDs were well-dispersed in water, fluorescent and we have characterized by XPS, XRD analysis, fluorescence and by FTIR spectra The MIC value by serial micro-dilution assays for CDs on S aureus ATCC 25923 was 250 μg/mL and E coli ATCC 25922 >1000 ug/mL For silver nanoparticles biogenically synthesized was 67 μg/mL Following the checkerboard assay with combining ½ MIC values of the MICs of 125 μg/mL of carbon dots and 34 μg/mL of silver nanoparticles, following the fractionated inhibitory concentration (FIC) index methodology, on S aureus gave a fractionated inhibitory concentration (FIC) value of 10, meaning additive interaction In general, the unfunctionalized CDs showed to be inefficient as antibacterial compounds, however the CDs extracted from Coffee powder and together silver nanoparticles appeared interesting as antibacterial association

Novel multiplex PCR for detection of diarrheagenic Escherichia coli strains isolated from stool and water samples.

Abstract: Diarrhea is considered the second most common cause of infant mortality worldwide. The disease can be caused by many different pathogens, including diarrheagenic Escherichia coli (DEC), which includes the pathotypes enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), Shiga toxin-producing E. coli (STEC), and enteropathogenic E. coli (EPEC). To develop a multiplex PCR system for the safe and accurate identification of the five main pathotypes of DEC, seven pairs of primers were determined for the following genes: aaiC, escV, bfpA, ipaH, elt, stx1, and stx2. To validate the system, 413 isolates from different sources (water and both animal and human stool) were analyzed that had been characterized previously. The sensitivity data were grouped by pathotype, in which 92.7% of the atypical EPEC were correlated, as were 92.8% of the STEC, 91.35% of the EAEC, and 100% of the typical EPEC, ETEC, and EIEC. These findings indicate that it is possible to detect the major five pathotypes of DEC from different sources, which can aid in determining the epidemiology of diarrhea with a low cost, high sensitivity and specificity, and the easy and safe viewing of the resulting PCR products.

Antibacterial Combination of Oleoresin from Copaifera multijuga Hayne and Biogenic Silver Nanoparticles Towards Streptococcus agalactiae.

Abstract: Background: Streptococcus agalactiae (group B Streptococcus - GBS) remains a leading cause of neonatal infections and an important cause of invasive infections in adults with underlying conditions. Methods: This study evaluated for the first time the effect of an oleoresin collected from Copaifera multijuga Hayne (copaiba oil) alone or in combination with silver nanoparticles produced by green synthesis using Fusarium oxysporum (AgNPbio) against planktonic and sessile cells of GBS isolated from colonized women. Results: Copaiba oil showed a dose-dependent bactericidal activity against planktonic GBS strains, including those resistant to erythromycin and/or clindamycin. Scanning and transmission electron microscopy of GBS treated with copaiba oil revealed morphological and ultrastructural alterations, displaying disruption of the cell wall and decreased electron density due to leakage of cytoplasmic content. Copaiba oil also exhibited antibacterial activity against biofilms of GBS strains, inhibiting their formation as well as the viability of mature biofilms. In addition, the combination of copaiba oil with AgNPbio resulted in a synergistic effect against planktonic cells and biofilm formation, reducing the minimal inhibitory concentration values of both compounds. No hemolytic activity was detected for both compounds. Conclusion: These results indicate the potential of copaiba oil, alone or in combination with AgNPbio, for the development of new alternative strategies for controlling GBS infections.

Perfil microbiológico e químico de extratos padronizados de inga marginata

Abstract: Doencas infecciosas vem apresentando crescente mortalidade no mundo, para o tratamento destas enfermidades as plantas se destacam por apresentar diversas especies que atuam como agentes terapeuticos. Inga marginata Willd esta classificado entre as dez especies de plantas mais importantes da regiao do medio Tibagi do estado do Parana. De acordo com alguns autores a atividade antimicrobiana de folhas de Inga marginata revela um potencial uso desta planta frente a alguns patogenos humanos. Mas devido a carencia de uma avaliacao mais precisa da especie, surgiu a necessidade de um estudo, visando elucidar algumas propriedades quimicas e microbiologicas desta planta. Com este trabalho foi possivel obter informacoes sobre as melhores condicoes de extracao dos compostos de interesse da planta por meio de um modelo de misturas, determinar o teor de compostos fenolicos totais e avaliar a atividade antimicrobiana da planta contra bacterias Gram positivas e negativas como S. aureus, S. epidermidis, E. coli e P. aeruginosa , como tambem para fungos como Candida albicans , C. tropicalis and C. glabrata . Com os resultados se constatou que os extratos 1 e 2 extraidos com somente agua e etanol, respectivamente, demonstraram efeito bacteriostatico contra os microorganismos testados. Isso demonstra uma potencial atividade antibacteriana dos extratos, podendo ser aplicados em formulacoes farmaceuticas com finalidade antisseptica. Desta forma, a especie pesquisada pode ser uma alternativa promissora para substituicao dos antissepticos usuais de origem sintetica por antissepticos de origem natural com menor toxicidade para o ser humano e meio ambiente.