Phage formulations and delivery strategies: Unleashing the potential against antibiotic-resistant bacteria.

Bacterial control promoted by bacteriophages (phages) is an attractive tool in the face of the antibiotic crisis triggered by the exacerbated use of these drugs. Despite the growing interest in using these viruses, some gaps still need answers, such as the protection and delivery of phages. Some limitation points involve the degradation of phage proteins by enzymes or inactivation in low-pH environments. In this review, a literature search using keywords related to the field of virus delivery formulations was done to understand the current scenario of using delivery techniques and phage formulations. A total of 2096 raw results were obtained, which resulted in 140 publications after refinement. These studies were analyzed for main application techniques and areas, keywords, and countries. Of the total, 57% of the publications occurred in the last five years, and the encapsulation technique was the most used among the articles analyzed. As excipient agents, lactose, trehalose, mannitol, PEG, and Leucine stand out. The development of phage formulations, protection approaches, their delivery routes, and the knowledge about the best application strategy enables the use of these organisms in several sectors. It can act as a powerful tool against antibiotic-resistant bacteria.

Relationship between SARS-CoV-2 vaccination and cases, program breakthrough cases, and deaths in Dois Vizinhos, Paraná, Brazil.

Several vaccines have been produced in 2 years of the COVID-19 pandemic to control the infection outbreak. This study demonstrated the success of vaccination in controlling COVID-19 cases and deaths in a small city (41 424 people) with a low population density in Brazil. This study was based on a 1-year dataset since the application of the first dose in January 2021. The results show a reduction in positive cases and deaths as the vaccination coverage increased in the city, mainly after 15 000 inhabitants were vaccinated (35.21% of the population) in July 2021. At the time, 49.06% of administered vaccines were ChAdOx1-S recombinant, 39.80% inactivated SARS-CoV-2 virus (CZ02 strain), 9.70% Tozinameran, and 1.44% Ad26.COV2-S recombinant. From August 2021, a marked reduction in daily positive cases and deaths was observed, and incidence (≤2.49 per 1000 inhabitants) and mortality (≤0.02 per 1000 inhabitants) rates remained stabilized until January 2022, when a new outbreak occurred upon the emergence of the Omicron variant. However, the mortality rate (0.07 per 1000 inhabitants) remained low regardless of the Omicron high incidence rate (68.41 per 1000 inhabitants). These data demonstrate the COVID-19 vaccination effectiveness with a threshold of 35.21% of the population vaccinated in this city model.

Bacteriophages in wastewater treatment: can they be an approach to optimize biological treatment processes?

In this paper, we explore the applications of bacteriophages and the advantages of using these viruses to control undesirable organisms in wastewater treatment plants. Based on this, this paper reviewed the literature on the subject by performing a bibliometric and scientometric analysis of articles published in peer-reviewed journals through 2021. We obtained 806 publications, of which 40% were published in the last 5 years, demonstrating an increase in interest in the subject. These articles analyzed, bacteriophages in treatment plants were strongly linked to bacteria such as Escherichia coli and related to disinfection, inactivation, sewage, and wastewater, in addition, biocontrol studies have gained prominence in recent years, particularly due to the resistance of microorganisms to antibiotics. Studies have shown that bacteriophages have great potential for application in treatment systems to control unwanted processes and act as valuable economic and environmental tools to improve the efficiency of various treatment technologies. Although these viruses have already been studied in various applications to optimize treatment plant processes, technology transfer remains a challenge due to the limitations of the technique-such as physicochemical factors related to the environment-and the complexity of biological systems. The research focusing on application strategies in conjunction with molecular biology techniques can expand this study area, enabling the discovery of new bacteriophages.

Influência da inoculação de rizóbios sobre a germinação e o vigor de plântulas de alface / Influence of rhizobial inoculation on seedling vigor and germination of lettuce

Os rizóbios, conhecidos por sua capacidade de fixar N2 em associação com leguminosas, também se mostram capazes de promover o crescimento de não-leguminosas, especialmente pela produção de ácido indol-acético (AIA). Neste trabalho, objetivou-se selecionar rizóbios produtores de AIA e avaliar o efeito de diferentes concentrações deste fitormônio sobre a germinação e o desenvolvimento inicial de plântulas de alface. Foram selecionados quatro isolados de Bradyrhizobium sp. e um isolado de Rhizobium leguminosarum biovar trifolii, os quais foram crescidos por quatro dias em meio levedura-manitol enriquecido com triptofano. Após esse período, avaliou-se a produção de AIA e procedeu-se à inoculação de sementes de alface com os isolados. O isolado TV-13, de R. leguminosarum biovar trifolii produziu 171,1µg mL-1 de AIA, causando prejuízos para o desenvolvimento das plântulas de alface. Por outro lado, os isolados de Bradyrhizobium sp. produziram entre 1,2 e 3,3µg mL-1 de AIA e aumentaram o vigor das plântulas em relação ao tratamento sem inoculação com rizóbios. Para verificar se essas diferenças foram decorrentes das concentrações de AIA, foram realizados mais dois experimentos, nos quais as sementes foram embebidas em culturas de TV-13 com ou sem a presença de triptofano ou em doses crescentes de AIA sintético. O isolado TV-13 crescido na presença de triptofano causou danos progressivos sobre o desenvolvimento das plântulas de alface, o que não ocorreu na ausência de triptofano. Também foi verificado um retardo na germinação das sementes quando submetidas a altas concentrações de AIA sintético. Os resultados indicam a influência do AIA sobre os parâmetros de germinação, de modo que a inoculação de sementes de alface com rizóbios que produzem baixas quantidades de AIA é uma prática recomendável.

Rhizobia are known by their ability to fix nitrogen in symbiosis with legumes, but they are also capable of promote the growth of non-legume, mainly due to indoleacetic acid production (IAA). In this research, it was aimed to select rhizobia producers of IAA and evaluate the effect of different levels of this hormone over the germination and initial development of lettuce seedlings. Four isolates of Bradyrhizobiumsp. and one isolate of Rhizobium leguminosarum biovar trifolii were grown during four days in yeast manitol medium enriched with tryptophan. After that period, the production of IAA was evaluated and the isolates were inoculated in lettuce seeds. The isolate TV-13, of R. leguminosarum biovar trifolii, produced 171.1µg mL-1 of IAA, causing damages to lettuce seedlings. On other hand, Bradyrhizobium sp. isolates produced between 1.2 and 3.3µg mL-1 of IAA and improved seedlings vigor. In order to verify if these results were due to IAA concentrations, other two assays were carried out, in which lettuce seeds were imbibed in TV-13 cultures with or without tryptophan or in increasing dosages of synthetic IAA. The isolate TV-13 grown in the presence of tryptophan caused progressive damages to lettuce seedlings development, fact that did not occur in the absence of tryptophan. It was also verified a delay in germination of seeds exposed to high levels of synthetic IAA. The results show the influence of IAA on germination parameters, so that the inoculation of lettuce seeds with rhizobia that produce low amounts of IAA is a recommended practice.