Showing papers by "Gerson Nakazato published in 2021"

Detection of ESBL/AmpC-Producing and Fosfomycin-Resistant Escherichia coli From Different Sources in Poultry Production in Southern Brazil.

Abstract: This study discussed the use of antimicrobials in the commercial chicken production system and the possible factors influencing the presence of Extended-spectrum β-lactamase (ESBL)/AmpC producers strains in the broiler production chain. The aim of this study was to perform longitudinal monitoring of ESBL-producing and fosfomycin-resistant Escherichia coli from poultry farms in southern Brazil (Parana and Rio Grande do Sul states) and determine the possible critical points that may be reservoirs for these strains. Samples of poultry litter, cloacal swabs, poultry feed, water, and beetles (Alphitobius sp.) were collected during three distinct samplings. Phenotypic and genotypic tests were performed for characterization of antimicrobial resistant strains. A total of 117 strains were isolated and 78 (66%) were positive for ESBL production. The poultry litter presented ESBL positive strains in all three sampled periods, whereas the cloacal swab presented positive strains only from the second period. The poultry litter represents a significant risk factor mainly at the beginning poultry production (odds ratio 6.43, 95% confidence interval 1–41.21, p < 0.05). All beetles presented ESBL positive strains. The predominant gene was blaCTX–M group 2, which occurred in approximately 55% of the ESBL-producing E. coli. The cit gene was found in approximately 13% of the ESBL-producing E. coli as AmpC type determinants. A total of 19 out of 26 fosfomycin-resistant strains showed the fosA3 gene, all of which produced ESBL. The correlation between fosA3 and blaCTX–M group 1 (blaCTX–M55) genes was significant among ESBL-producing E. coli isolated from Parana (OR 3.66, 95% CI 1.9–9.68) and these genetic determinants can be transmitted by conjugation to broiler chicken microbiota strains. Our data revealed that poultry litter and beetles were critical points during poultry production and the presence of fosfomycin-resistant strains indicate the possibility of risks associated with the use of this antimicrobial during production. Furthermore, the genetic determinants encoding CTX-M and fosA3 enzymes can be transferred to E. coli strains from broiler chicken microbiota, thereby creating a risk to public health.

Subinhibitory Concentrations of Biogenic Silver Nanoparticles Affect Motility and Biofilm Formation in Pseudomonas aeruginosa.

Abstract: Biogenic silver nanoparticles (bio-AgNPs) are increasingly recognized as an antibiofilm and antivirulence strategy against P. aeruginosa, a bacterium that causes chronic infections in immunocompromised and cystic fibrosis patients. This study aimed to investigate the effects of subinhibitory concentrations of bio-AgNPs on motility and biofilm formation in P. aeruginosa. Bio-AgNPs were synthesized via reduction of ionic silver catalyzed by cell-free culture filtrate from Fusarium oxysporum. A total of 17 P. aeruginosa isolates and strains were evaluated for swarming, swimming, and twitching motility in the presence and absence (control) of bio-AgNPs, including 10 clinical isolates from patients with and without cystic fibrosis, 5 environmental isolates obtained from the public water supply system, and 2 reference strains (PAO1 and PA14). Isolates were identified by biochemical and molecular methods. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method. Swarming, swimming, and twitching motility assays were performed in Petri dishes. Biofilm formation capacity was assessed quantitatively by the crystal violet method. MIC values ranged from 15.62 to 62.50 µM. The results showed that subinhibitory concentrations of bio-AgNPs (½ MIC, 7.81-31.25 µM) significantly increased (p < 0.05) swarming, swimming, and twitching motility in 40.0, 40.0, and 46.7% of isolates, respectively. Subinhibitory bio-AgNP treatment enhanced (p < 0.05) biofilm formation capacity in PA14 and a cystic fibrosis isolate (P11). It is concluded that subinhibitory concentrations of bio-AgNPs increased biofilm formation and swarming, swimming, and twitching motility in PA14 and some P. aeruginosa isolates. These virulence factors are directly involved with quorum-sensing systems. Further research should investigate the effects of AgNPs on P. aeruginosa quorum sensing to help elucidate their mechanism of action at subinhibitory concentrations.

Multi-target drug with potential applications: violacein in the spotlight.

Abstract: The aim of the current review is to address updated research on a natural pigment called violacein, with emphasis on its production, biological activity and applications. New information about violacein’s action mechanisms as antitumor agent and about its synergistic action in drug delivery systems has brought new alternatives for anticancer therapy. Thus, violacein is introduced as reliable drug capable of overcoming at least three cancer hallmarks, namely: proliferative signaling, cell death resistance and metastasis. In addition, antimicrobial effects on several microorganisms affecting humans and other animals turn violacein into an attractive drug to combat resistant pathogens. Emphasis is given to effects of violacein combined with different agents, such as antibiotics, anticancer agents and nanoparticles. Although violacein is well-known for many decades, it remains an attractive compound. Thus, research groups have been making continuous effort to help improving its production in recent years, which can surely enable its pharmaceutical and chemical application as multi-task compound, even in the cosmetics and food industries.

Antibacterial activity of honeys from Amazonian stingless bees of Melipona spp. and its effects on bacterial cell morphology

Abstract: Background Stingless bee honey has great therapeutic potential, especially as an antimicrobial agent. In the present study, we evaluated the in vitro antibacterial potential of honey from Melipona spp. with occurrence in Rio Branco-AC and Xapuri-AC from the Amazonian region. Samples were collected from the species Melipona eburnea, Melipona grandis, Melipona flavolineata and Melipona seminigra. The antibacterial activity of the honey samples was tested against standard Gram-positive and Gram-negative bacteria and two strains isolated from bovine mastitis. Results In the agar diffusion assay, we observed antibacterial activity for the four honeys against the tested strains. The honey from M. flavolineata showed a minimmum inhibitory concentration (MIC) lower than 3.12% (v/v). The minimum bactericidal concentration values were larger than the MIC for most of the microorganisms tested. Scanning electron microscopy (SEM) showed the damaging effect of the honey of M. flavolineata on Staphylococcus aureus cells, as well as its inhibitory effect on cell division. Conclusion The results of the present study demonstrate that the honey from stingless bees possesses in vitro antimicrobial activity against pathogenic bacteria. The effects observed by SEM show that honey from the Amazonian stingless bee M. flavolineata has promising therapeutic potential as a future antimicrobial agent. © 2020 Society of Chemical Industry.

Biogenic Silver Nanoparticles Can Control Toxoplasma gondii Infection in Both Human Trophoblast Cells and Villous Explants.

Abstract: The combination of sulfadiazine and pyrimethamine plus folinic acid is the conventional treatment for congenital toxoplasmosis. However, this classical treatment presents teratogenic effects and bone marrow suppression. In this sense, new therapeutic strategies are necessary to reduce these effects and improve the control of infection. In this context, biogenic silver nanoparticles (AgNp-Bio) appear as a promising alternative since they have antimicrobial, antiviral, and antiparasitic activity. The purpose of this study to investigate the action of AgNp-Bio in BeWo cells, HTR-8/SVneo cells and villous explants and its effects against Toxoplasma gondii infection. Both cells and villous explants were treated with different concentrations of AgNp-Bio or combination of sulfadiazine + pyrimethamine (SDZ + PYZ) in order to verify the viability. After, cells and villi were infected and treated with AgNp-Bio or SDZ + PYZ in different concentrations to ascertain the parasite proliferation and cytokine production profile. AgNp-Bio treatment did not reduce the cell viability and villous explants. Significant reduction was observed in parasite replication in both cells and villous explants treated with silver nanoparticles and classical treatment. The AgNp-Bio treatment increased of IL-4 and IL-10 by BeWo cells, while HTR8/SVneo cells produced macrophage migration inhibitory factor (MIF) and IL-4. In the presence of T. gondii, the treatment induced high levels of MIF production by BeWo cells and IL-6 by HTR8SV/neo. In villous explants, the AgNp-Bio treatment downregulated production of IL-4, IL-6, and IL-8 after infection. In conclusion, AgNp-Bio can decrease T. gondii infection in trophoblast cells and villous explants. Therefore, this treatment demonstrated the ability to reduce the T. gondii proliferation with induction of inflammatory mediators in the cells and independent of mediators in chorionic villus which we consider the use of AgNp-Bio promising in the treatment of toxoplasmosis in BeWo and HTR8/SVneo cell models and in chorionic villi.

Metal Nanoparticles against Viruses: Possibilities to Fight SARS-CoV-2

Abstract: In view of the current Coronavirus Disease 2019 (COVID-19) pandemic outbreak, the research community is focusing on development of diagnostics, treatment, and vaccines to halt or reverse this scenario. Although there are already various vaccines available, adaptive mutations in the SARS-CoV-2 genome can alter its pathogenic potential and, at the same time, increase the difficulty of developing drugs or immunization by vaccines. Nanotechnology carries a potential to act in all stages in fighting this viral disease, with several possibilities of strategies such as applying nanoparticles directly as antivirals in delivery systems against these viruses or incorporating them in materials, with power of achievement in therapeutics, vaccines and prevention. In this paper, we review and bring insights of recent studies using metal nanocomposites as antivirals against coronavirus and structurally similar viruses.

Multifunctional hybrid nanoplatform based on Fe3O4@Ag NPs for nitric oxide delivery: development, characterization, therapeutic efficacy, and hemocompatibility.

Abstract: The combination of Fe3O4@Ag superparamagnetic hybrid nanoparticles and nitric oxide (NO) represents an innovative strategy for a localized NO delivery with a simultaneous antibacterial and antitumoral actions. Here, we report the design of Fe3O4@Ag hybrid nanoparticles, coated with a modified and nitrosated chitosan polymer, able to release NO in a biological medium. After their synthesis, physicochemical characterization confirmed the obtention of small NO-functionalized superparamagnetic Fe3O4@Ag NPs. Antibacterial assays demonstrated enhanced effects compared to control. Bacteriostatic effect against Gram-positive strains and bactericidal effect against E. coli were demonstrated. Moreover, NO-functionalized Fe3O4@Ag NPs demonstrated improved ability to reduce cancer cells viability and less cytotoxicity against non-tumoral cells compared to Fe3O4@Ag NPs. These effects were associated to the ability of these NPs act simultaneous as cytotoxic (necrosis inductors) and cytostatic compounds inducing S-phase cell cycle arrest. NPs also demonstrated low hemolysis ratio (<10%) at ideal work range, evidencing their potential for biomedical applications. Targeted and hemocompatible nitric oxide-releasing multi-functional hybrid nanoparticles for antitumor and antimicrobial applications.

Violacein, A Microbial Antiviral Product: Does Play Key Role as Active Agent Against SARS-CoV-2?

Abstract: Violacein, a microbial product was characterized after continuous attempts to feature it, based on degradation and synthesis procedures, at the University of Liverpool (England), from 1958 to 1960 and only at 2001 was chemically synthesized. It is a quite known antimicrobial and antiviral natural product. New attempts to solve the infection caused by, or find the proper therapy for, COVID19, must adopt multidisciplinary approach. The aim of the current study is to address the targets, possible strategies and perspectives of new technologies and therapies on COVID19. It also hypothesizes the potential of using the therapeutic drug called violacein as multifunctional agent to treat patients at different COVID19 contamination stages. Our experience and knowledge about violacein has led us to extrapolate the potential use of this pigment. Violacein multiple biological activities as also knowledge on its toxicity and antiviral activity enabled suggesting that it could be the new important agent used to treat COVID19. Violacein is highly likely to act as protease inhibitor, at ACE2 receptor level and as immunotherapeutic drug against Covid19. In term of chemotherapy, it will be discussed the actual antiviral used against COVID19, such as, thalidomide, ivermectin and melatonin, among others.

Patents on Violacein: A Compound with Great Diversity of Biological Activities and Industrial Potential.

Abstract: Background This review outlines to envisage the current impact of violacein-derivative materials in several technological areas through patents. Methods A comprehensive examination up to day patent databases on violacein demonstrated the relevance of this pigment, as well as the pertinent topics related to its technological development in order to obtain adaptable new pharmaceuticals, cosmetics and new quality fiber materials, together with others applications of violacein in different areas. Results At present time, there is no efficient and economical feasible technique for violacein preparation at industrial scale. Many attempts have been developed but none have achieved the big challenge of being effective and inexpensive process. However, some potential applications of violacein in fields like biomedicine make the pigment worth to continuous the investigations. Particularly, violacein patents covering from biosynthesis to different applications were reported recently. Conclusion As unique pigment, violacein has been used in distinct areas of specialties, such as in medical and industrial fields. Then, this review through patents provides an update on violacein innovations useful for researchers working in an expandable and interesting field of biotechnology with natural pigments.

Antibacterial effect and clinical potential of honey collected from Scaptotrigona bipunctata Lepeletier (1836) and Africanized bees Apis mellifera Latreille and their mixture

Abstract: Bacterial resistance to conventional antibacterial agents is a clinical issue which requires the constant search for new therapies. This study evaluated the antibacterial activity of honey produced...

Genomic insights of high-risk clones of ESBL-producing Escherichia coli isolated from community infections and commercial meat in Southern Brazil

Abstract: During a microbiological and genomic surveillance study to investigate the molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli from community-acquired urinary tract infections (UTI) and commercial meat samples, in a Brazilian city with a high occurrence of infections by ESBL-producing bacteria, we have identified the presence of CTX-M (-55, -27, -24, -15, -14 and -2)-producing E. coli belonging to the international clones ST354, ST131, ST117, and ST38. The ST131 was more prevalent in human samples, and worryingly the high-risk ST131-C1-M27 was identified in human infections for the first time. We also detected CTX-M-55-producing E. coli ST117 isolates from meat samples (i.e., chicken and pork) and human infections. Moreover, we have identified the important clone CTX-M-24-positive E. coli ST354 from human samples in Brazil for the first time. In brief, our results suggest a potential of commercialized meat as a reservoir of high-priority E. coli lineages in the community. In contrast, the identification of E. coli ST131-C1-M27 indicates that novel pandemic clones have emerged in Brazil, constituting a public health issue.

What Do We Know About and What Could Be the Strategy Adopted to Treat Mucormycosis on Post-COVID-19 Cases? Is It an Adjuvant Nanomaterial?

Abstract: Unfortunately, Coronavirus disease 2019 (COVID-19) remains a significant public health issue worldwide, mainly in the USA, India and Brazil. The 2nd wave of COVID-19 has reached India first. The country has been making great effort to stabilize its current condition but, unfortunately, mucormycosis infection (or black fungus) associated with COVID-19 has emerged as another threat to the country and, most likely, to Brazil. It may have happened due to excessive glucocorticoid using, since the widespread administration of this drug can lead to secondary fungal infections. Mucormycosis is generated by a group of molds called mucormycetes; it is a rare, although likely fatal, contamination when patients are not properly treated. The concerning factor lies on the fact that the high COVID-19 incidence recorded in the first wave of it has increased even faster in its second wave in India; there have been some concerning cases in Brazil, as well. The current overview addresses the current therapies used to treat mucormycosis worldwide, as well as potential and new drugs for such a specific treatment. Anti-mucormycosis adjuvants and nanomaterials are the most interesting alternatives to treat patients with post-COVID-19 mucormycosis.

Segurança dos alimentos: merendeiras conhecendo a microbiologia para promoção do alimento seguro na escola

Abstract: Foodborne diseases are a major public health concern. Food handlers need to be increasingly aware of the risks that exist when handling food inappropriately. Many foodborne diseases can be prevented if food handlers are better trained and aware of the care needed for good hygiene practices in food handling. Therefore, the objective of this extension project was to promote food safety at school by providing to lunch ladies and kitchen assistants knowledge of microbiology through theoretical-practical classes on basic microbiology, Gram staining, microbiota, importance of microorganisms for food, pathogenic microorganisms, food disinfection and nutritional aspects. The classes were taught by students of Graduate programs at the State University of Londrina. We attend around 220 lunch ladies from Londrina and the region and, through interviews, we heard reports about the changes in practices in food preparation within the schools and in their homes; they also reported the importance of the course in learning about food care and hygiene. As part of the course evaluation, some classes answered a questionnaire, before and after the course, about the content taught. Thus, it was found that the project promoted a greater awareness of care with food handling and regarding the important role of lunch ladies in promoting safe foods in schools.

Innate immunity in chicken lines developed by EMBRAPA Suínos e Aves: antimicrobial activity of macrophages and serum

Abstract: The objective of this study was to compare the antimicrobial activity of macrophages and serum in laying hen (MM, CC, and CCc) and broiler chicken lineages (TT and LL). Macrophages were evaluated for phagocytic and antimicrobial activity. Microbicidal serum activity was evaluated by the resistance test for serum and the agar test. The results showed that phagocytic activity was higher in males of the MM strain, with 13% of macrophages presenting phagocytosis, while the other lineages studied, and even [...]