Polystyrene nanoplastics induce developmental impairments and vasotoxicity in zebrafish (Danio rerio).

The exponential use of plastics has significantly increased environmental pollution by nanoplastics (NPs). In the aquatic environment, NPs interact and bioaccumulate in the biota, posing a potential ecotoxicological risk. The present study investigated the developmental toxicity, vasotoxicity, cytotoxicity, ROS induction, and behavioral impairments in zebrafish (Danio rerio) exposed to environmentally relevant polystyrene NPs (PS-NPs) concentrations (0.04, 34 ng L-1, and 34 µg L-1) for 144 h through multiple biomarkers response (mortality, frequency of spontaneous contractions, heart rate, and morphological changes). Furthermore, vasotoxicity (head, yolk sac, tail, and branchial vessels) was evaluated using the transgenic zebrafish tg(Fli1:eGFP). Results showed that PS-NPs interacted mainly with zebrafish chorion, gills, tail, and larvae head. PS-NPs at 34 ng L-1 and 34 µg L-1 induced neurotoxicity (decreased frequency of spontaneous contractions), cardiotoxicity (bradycardia), and morphological changes in the eyes and head, indicating that PS-NPs induce developmental impairments in zebrafish. In addition, cytotoxicity in the caudal region (34 ng L-1), ROS production, decreased mean swimming speed, and distance covered were observed in all tested concentrations. PS-NPs also induced vasotoxicity (yolk sac region) in transgenic zebrafish. Overall, the present study demonstrates the harmful effects of PS-NPs on the early developmental stages of freshwater fish, indicating their environmental risk.

Microbiome: A forgotten target of environmental micro(nano)plastics?

Microplastics (MPs) and nanoplastics (NPs) are emerging pollutants in different environmental compartments (air, soil and water) and that may induce several ecotoxicological effects on organisms and their microbiota. A considerable number of studies has been addressing and highlighting the effects of MPs/NPs on biochemical, molecular and behavior effects of aquatic organisms. However, less attention has been focused on microbiota. Here, a critical overview of published studies focusing on microorganisms affected by MPs and NPs after in vitro or in vivo exposure is provided. Available studies regarding the properties of MPs/NPs, microbial phyla, experimental conditions, techniques employed, and effects are summarized. The link between microbiota disruption and other effects on other hosts (e.g., crustaceans, fish, and mammals) as also analyzed. Overall, the literature review shows that most studies with microorganisms were performed in vitro (MPs: 44.11%; NPs: 23.52%) in comparison with in vivo tests (MPs: 32.35%; NPs: 11.76%). The most studied MP/NPs were polystyrene particles, generally spheres, with sizes <50 µm and concentrations ranged between 100 and 1000 mg L-1. The most studied main phyla were Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. MPs/NPs induced microbiome composition disruption, immune response (i.e., immune modulator release, immune cells activation and inflammatory response), enzyme activity changes (i.e., catalase, urease, dehydrogenase, alkaline phosphatase, and fluorescein diacetate hydrolase) and gene expression changes. The immune responses changes were related to microbiome disruption. Research gaps are highlighted and recommendations for future research indicated that microbiome is sensitive to MP/NPs and microbiome disruption can be a valuable tool to assess the risk of plastic particles to human and environmental health.

Detection of resistance genes in pyometra isolated bacteria in bitches / Detecção de genes de resistência em bactérias isoladas de piometra em cadelas

Pyometra has several immunological and molecular changes that are responsible for uterine inflammation and the disease may or may not have infections. This study aimed to isolate and identify bacteria in the uterine content of bitches with pyometra, to analyze the susceptibility profile to antibiotics, detect ß-lactamase enzyme production by phenotypic tests, and resistance genes to ß-lactams. Eighteen samples of uterine content were collected by aspiration puncture. The samples were inoculated in bacteriological media and identified by biochemical tests. Subsequently, antibiogram tests, screening for detection of ß-lactamases, and Real-Time PCR for detection of resistance genes was performed. Escherichia coli, Klebsiella spp., Enterobacter aerogenes, Citrobacter spp., Staphylococcus spp., and Streptococcus spp. were identified in the analyzed samples of uterine content. In the antibiogram test, 90.5% of the isolates showed resistance to at least one antibiotic, and of these, 36.8% were considered MDR, with three Staphylococcus spp., three E. coli, and one Klebsiellaspp. Concerning bacterial resistance to the groups of antibiotics tested, 38.1% of the isolates were resistant to at least one type of ß-lactam, 33.3% to tetracycline, 19.0% to aminoglycosides, and 14.3% to fluoroquinolones, macrolides, and trimethoprim-sulfamethoxazole. In the phenotypic test to detect ß-lactamase production, E. coli samples were negative and Klebsiella spp. was positive for the production of AmpC, which presented the blaCMY, blaSPM, and blaSIM genes. Bacteria that are resistant to antibiotics represent a great challenge and laboratory support is therefore essential, without which therapeutic success decreases and death may be inevitable.(AU)

A piometra apresenta diversas alterações imunológicas e moleculares que são responsáveis pela inflamação uterina, e a doença pode ser infecciosa ou não. O objetivo deste estudo foi isolar e identificar bactérias no conteúdo uterino de cadelas com piometra, analisar o perfil de suscetibilidade aos antibióticos, detectar a produção de enzimas ß-lactamase por testes fenotípicos e genes de resistência aos ß-lactâmicos. Dezoito amostras de conteúdo uterino foram coletadas por punção aspirativa. As amostras foram inoculadas em meio bacteriológico e identificadas por testes bioquímicos. Posteriormente, foram realizados testes de antibiograma, triagem para detecção de ß-lactamases e PCR em tempo real para detecção de genes de resistência. Escherichia coli, Klebsiella spp., Enterobacter aerogenes, Citrobacter spp., Staphylococcus spp. e Streptococcus spp. foram identificados nas amostras de conteúdo uterino analisadas. No teste de antibiograma, 90,5% dos isolados apresentaram resistência a pelo menos um antibiótico, e destes, 36,8% foram considerados MR, sendo três Staphylococcus spp., três E. coli e uma Klebsiella spp. Sobre a resistência bacteriana aos grupos de antibióticos testados, 38,1% dos isolados foram resistentes a pelo menos um tipo de ß-lactâmico, 33,3% à tetraciclina, 19,0% aos aminoglicosídeos e 14,3% às fluorquinolonas, macrolídeos e trimetoprim-sulfametoxazol. No teste fenotípico para detecção da produção de ß-lactamase, as amostras de E. coli foram negativas, e Klebsiella spp. foi positiva para a produção de AmpC, que apresentou os genes blaCMY, blaSPM e blaSIM. As bactérias resistentes aos antibióticos representam um grande desafio e, portanto, o suporte laboratorial é essencial, sem o qual o sucesso terapêutico diminui e a morte pode ser inevitável.(AU)

Profile of Enterobacteria Resistant to Beta-Lactams.

A serious emerging problem worldwide is increased antimicrobial resistance. Acquisition of coding genes for evasion methods of antimicrobial drug mechanisms characterizes acquired resistance. This phenomenon has been observed in Enterobacteriaceae family. Treatment for bacterial infections is performed with antibiotics, of which the most used are beta-lactams. The aim of this study was to correlate antimicrobial resistance profiles in Enterobacteriaceae by phenotypic methods and molecular identification of 14 beta-lactamase coding genes. In this study, 70 exclusive isolates from Brazil were used, half of which were collected in veterinary clinics or hospitals Phenotypic methodologies were used and real-time PCR was the molecular methodology used, through the Sybr Green system. Regargding the results found in the tests it was observed that 74.28% were resistant to ampicillin, 62.85% were resistant to amoxicillin associated with clavalunate. The mechanism of resistance that presented the highest expression was ESBL (17.14%). The genes studied that were detected in a greater number of species were blaGIM and blaSIM (66.66% of the samples) and the one that was amplified in a smaller number of samples was blaVIM (16.66%). Therefore, high and worrying levels of antimicrobial resistance have been found in enterobacteria, and a way to minimize the accelerated emergence of their resistance includes developing or improving techniques that generate diagnoses with high efficiency and speed.