Taniara Suelen Mezalira

Resumo A resistência antimicrobiana em cepas de Escherichia coli tem contribuído para a busca por produtos alternativos ao seu uso, como os extratos vegetais. O objetivo deste estudo foi avaliar o perfil dos genes de resistência a cefalosporinas em isolados de E. coli com fenótipo de produção de beta-lactamase de espectro estendido (ESBL), a composição fenólica e a atividade antibacteriana do extrato etanólico de Pereskia aculeata contra cepas isoladas de frangos de um dia de vida e em crescimento. Para determinar a Concentração Inibitória Mínima (CIM) e a Concentração Bactericida Mínima (CBM) do extrato etanólico de P. aculeata, foram selecionados isolados de E. coli que apresentaram perfil ESBL em uma das origens (pintos de um dia ou frangos em crescimento). Os genes de resistência blaCTX-M-1, blaCTX-M-2, blaCTX-M-8 e blaSHV foram detectados com maior percentual em isolados de frangos em crescimento. O extrato de P. aculeata apresentou diversos compostos fenólicos, sendo o ácido málico e a rutina os predominantes. A determinação da CIM foi possível em apenas dois isolados de E. coli, um do Aviário A (frangos em crescimento) e outro do Aviário B (pintos de um dia). Em ambos os casos, a CIM foi de 20 mg/mL. Na cepa ATCC 25922 de E. coli, utilizada como cepa padrão para a avaliação do teste, a CIM foi de 20 mg/mL. Conclui-se que isolados de E. coli provenientes de pintos de um dia e frangos em crescimento carregam genes de resistência a cefalosporinas, e que não há diferença na CIM do extrato etanólico de P. aculeata Mill. quando comparadas cepas com perfil fenotípico ESBL àquelas que não apresentam esse perfil, demonstrando a necessidade de estudos adicionais com plantas com potencial antimicrobiano.

Antimicrobial resistance in Escherichia coli strains has contributed to the search for alternative antimicrobial products, such as plant extracts. The objective of this study was to evaluate the profile of cephalosporin-resistance genes in E. coli isolates with an extended-spectrum ß-lactamase (ESBL) production phenotype, and the phenolic composition and antibacterial activity of the ethanolic extract of Pereskia aculeata against strains isolated from 1-day-old and growing chickens. To determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the ethanolic extract of P. aculeata, E. coli isolates that exhibited an ESBL profile when isolated from either 1-day-old chicks or growing chickens were selected. The resistance genes blaCTX-M-1, blaCTX-M-2, blaCTX-M-8, and blaSHV were detected in a higher percentage of isolates from growing chickens. The P. aculeata extract was found to contain several phenolic compounds, with malic acid and rutin being predominant. Determination of MIC was only possible for two E. coli isolates (one from Broiler house A (growing chickens) and the other from Broiler house B (1-day-old chicks) - and for the standard strain E. coli ATCC 25922; in all cases, the MIC was 20 mg/mL. These findings indicate that E. coli isolates from both age groups carried cephalosporin-resistance genes and exhibit similar susceptibility to the P. aculeata extract, regardless of ESBL phenotype. These results highlight the need for further research into plant-based antimicrobials.

Currently, the use of exogenous enzymes in the diet of broilers has grown, not only in diets based on corn and soybean meal, but also in diets with proteins of animal origin. The objective of this study was to evaluate the effect of supplementing a multi-carbohydrase complex (xylanase, glucanase, other carbohydrases) with phytase (MCCP) in broiler diets containing animal ingredients on performance, litter quality, jejunum morphometry and feed cost. Three treatments were evaluated: T1 - positive control diet: reference diet; T2 - negative control diet + MCCP; T3 - negative control diet (reference ration minus the MCCP nutritional matrix), with five replicates per treatment, totaling 15 experimental units of 15 female chicks each for an experimental period of 47 days. It was found that the T1 animals showed better feed conversion when compared to the T2 and T3 in the period from one to 21 days. In addition, greater weight at 28 days was found for T1compared to T3. The greater villus height of the jejunum at seven days was verified for the T3 animals concerning the T2 and T1 treatments. There were no differences between treatments in relation to the litter quality and the cost of the feed to produce one kilogram of broiler chicken. It is concluded that the supplementation of the MCCP in broiler chicken diets with ingredients of animal origin does not improve the performance, does not modify the jejunum morphometric, litter quality, and cost parameters evaluated. Keywords: Feed Conversion. Glucanase. Phytase. Villus Height. Xylanase. Resumo Atualmente, tem crescido o uso de enzimas exógenas na dieta de frangos de corte, não só em rações à base de milho e farelo de soja, mas também em rações com proteínas de origem animal. O objetivo deste estudo foi avaliar o efeito da suplementação de um complexo multi-carboidrase (xilanase, glucanase, outras carboidrase) com fitase (CMCF) em dietas de frangos de corte contendo ingredientes de origem animal sobre o desempenho, qualidade da cama, morfometria do jejuno e custo da alimentação. Foram avaliados três tratamentos: T1 - dieta controle positivo: dieta referência; T2 - dieta controle negativo + CMCF; T3 - dieta controle negativo (ração referência menos a matriz nutricional CMCF), com cinco repetições por tratamento, totalizando 15 unidades experimentais de 15 pintos fêmeas cada, por um período experimental de 47 dias. Verificou-se que os animais T1 apresentaram melhor conversão alimentar quando comparados aos T2 e T3 no período de um a 21 dias. Além disso, maior peso aos 28 dias foi encontrado para T1 em relação a T3. Maior altura de vilo do jejuno aos sete dias foi verificada para os animais T3 em relação aos tratamentos T2 e T1. Não houve diferenças entre os tratamentos em relação à qualidade da cama e ao custo da ração para produzir um quilo de frango de corte. Conclui-se que a suplementação do CMCF em rações de frangos de corte com ingredientes de origem animal não melhora o desempenho, não altera os parâmetros morfométricos do jejuno, a qualidade da cama e o custo avaliado. Palavras-chave: Altura de vilo. Conversão alimentar. Fitase. Glucanase. Xilanase.

Background: Peptidoglycan (PG) is a key structural component of the bacterial cell wall and interruption of its biosynthesis is a validated target for antimicrobials. Of the enzymes involved in PG biosynthesis, D-alanyl,D-alanine ligase B (DdlB) is responsible for the condensation of two alanines, forming D-Ala-D-Ala, which is required for subsequent extracellular transpeptidase crosslinking of the mature peptidoglycan polymer. Objective: We aimed at the biophysical characterization of recombinant Escherichia coli DdlB (EcDdlB), considering parameters of melting temperature (T_m), calorimetry and Van’t Hoff enthalpy changes of denaturation ( ΔH^U_cal and ΔH^U_vH ), as well as characterization of elements of secondary structure at three different pHs. Methods: DdlB was overexpressed in E. coli BL21 and purified by affinity chromatography. Thermal stability and structural characteristics of the purified enzyme were analyzed by circular dichroism (CD), differential scanning calorimetry and fluorescence spectroscopy. Results: The stability of EcDdlB increased with proximity to its pI of 5.0, reaching the maximum at pH 5.4 with T_m and ΔH^U_vH U of 52.68 ºC and 484 kJ.mol^-1, respectively. Deconvolutions of the CD spectra at 20 ºC showed a majority percentage of α-helix at pH 5.4 and 9.4, whereas for pH 7.4, an equal contribution of β-structures and α-helices was calculated. Thermal denaturation process of EcDdlB proved to be irreversible with an increase in β-structures that can contribute to the formation of protein aggregates. Conclusion: Such results will be useful for energy minimization of structural models aimed at virtual screening simulations, providing useful information in the search for drugs that inhibit peptidoglycan synthesis.

The objective of this experiment was to evaluate the benefits of acetic acid in different periods of inclusion in broiler drinking water on broiler performance, pH, and microbiota, especially the morphometry of the jejunum of broiler chickens. For this, 240 chickens of the Cobb500® lineage of 21 days of age were used and distributed in boxes in an experimental broiler house, considering a completely randomized design, with four treatments and four replications of 15 birds each (experimental unit). The treatments were: T_{1 -} Control (chlorinated water at 3 ppm); T_{2 -} chlorinated and acidified water with acetic acid in the period from 21 to 42 days of age; T₃- chlorinated and acidified water with acetic acid in the period from 28 to 42 days of age; T_{4 -} chlorinated and acidified water with acetic acid in the period from 35 to 42 days of age. The results were analyzed using Analysis of Variance, followed by Tukey's post-test, considering a significance level of 5%. No differences in performance were observed in the period from 21 to 42 days of age, pH, and Lactobacillus spp. counts of the crop at 42 days of age and height of villi and jejunum crypt depth in the same age. However, there was a reduction (P<0.05) in the enterobacteria count in the crop at 42 days of age, which could contribute to the reduction of intestinal enterobacteria counts and, in turn, reduce the contamination of the carcass of broiler chickens.

The indiscriminate use of antibiotics in veterinary medicine and their negligent use among dog owners have contributed to the rise of antibiotic resistance in microorganisms found in pets. In addition, the search for medicinal plants with antibacterial properties has made the evaluation of aqueous extracts of Alpinia purpurata (Vieill.) K. Schum an important issue. Thus, the aim of this work was to determine the antibiotic resistance profile of gram-negative bacteria isolated from nasal swab samples of dogs and assess the antibacterial activity of the aqueous extracts of leaves and rhizomes of A. purpurata. The bacteria identified were tested using the agar disc diffusion assay for the evaluation of antibiotic resistance. A total of 16 isolates were obtained from the 19 samples collected, with a high prevalence of Escherichia coli (n=5). There was a high rate of resistance to ?-lactams, where the highest percentage was seen for amoxicillin (72.5%). Aqueous leaf extracts had high levels of total phenolic compounds (637.47 µg GAE mg-1), differing significantly (p < 0.05) from aqueous rhizome extracts (228.64 µg GAE mg-1). There was no significant difference in EC50 of DPPH values between the aqueous extracts; however, the antioxidant capacity of rhizome extracts had higher values than leaf extracts. The minimum inhibitory concentration (MIC) of leaves and rhizomes for the evaluated bacteria ranged from 9000 to 32,000 µg mL-1. For the minimum bactericidal concentration (MBC), most bacteria showed an MBC over 38,400 µg mL-1 for the rhizome. In conclusion, the bacteria isolated from dog nasal swabs showed a high resistance profile for the antibiotics of the penicillin class. Additionally, the results from the analysis of the aqueous extracts of rhizomes and leaves of A. purpurata showed an antimicrobial effect possibly associated with a high content of total phenolic compounds; these results can create a scope for using these extracts together with conventional antibiotics to control the emergence of antibiotic resistance among microbial species.

O objetivo desse trabalho foi comparar o desempenho zootécnico e o custo de produção de diferentes linhagens de frangos de corte (Cobb Slow, Cobb Fast e Hubbard), sistemas de ventilação (positiva e negativa) e tipos de aviário (lona amarela/convencional, blue house e dark house). Foi realizado um levantamento de dados de desempenho e custo de duas granjas avícolas localizadas na região oeste do estado do Paraná, no período de 25 de setembro de 2012 a 25 de setembro de 2017. Verificou-se que as linhagens Hubbard e Cobb Slow apresentaram melhores resultados nas variáveis índice de eficiência produtiva (IEP) (356,3 vs. 334,6) e peso médio final (3,014 kg vs. 2,902 kg). A linhagem Hubbard também mostrou significativamente maior ganho médio diário de peso (GMDP) em relação às duas outras linhagens, com uma média de 64,4 g. Em relação ao sistema de ventilação, verificou-se que a ventilação negativa é mais eficiente do que a positiva quando avaliado o GMDP, e que os sistemas dark e blue house mostraram um desempenho superior ao sistema convencional (lona amarela). Conclui-se que animais da linhagem Hubbard e Cobb Slow apresentam melhores resultados de desempenho zootécnico (IEP, peso médio) do que animais da linhagem Cobb Fast. Em relação ao sistema de ventilação (positiva e negativa) e tipos de aviário (dark house, blue house e convencional), melhores resultados de desempenho zootécnico são observados para sistemas que propiciam melhor ambiência, ou seja, ventilação negativa e com controle de luminosidade (dark e blue house). Por outro lado, em termos de custos, não houve diferenças nos parâmetros avaliados.

Devido ao uso de antibióticos para o tratamento e prevenção de infecções bacterianas durante a produção de matrizes pesadas, torna-se importante estudar o perfil de resistência e a prevalência de bactérias gram-negativas produtoras de ESBL. Dentre as várias classes de antimicrobianos disponíveis, destacam-se os agentes beta-lactâmicos, categoria antimicrobiana amplamente utilizada em clínica médica humana e veterinária. Assim, este trabalho teve como objetivo avaliar o perfil de resistência e caracterizar as cepas produtoras de beta-lactamases de espectro estendido (ESBL) isoladas de matrizes de corte por meio da coleta de 87 swabs cloacais. As bactérias Gram-negativas foram isoladas em meios seletivos, identificadas por métodos bioquímicos convencionais e MALDI-TOF® e estudadas quanto à resistência antimicrobiana, incluindo ESBL. Das 87 amostras, foram isoladas 52 bactérias gram-negativas. Houve alta resistência bacteriana às principais classes de antimicrobianos utilizados em aves: penicilinas, cefalosporinas e quinolonas. Também foi encontrado fenótipo sugestivo de produção de ESBL em 42,31% dos isolados, demonstrando resistência aos antimicrobianos beta-lactâmicos testados. Os resultados demonstram a necessidade de orientação dos profissionais que trabalham com matrizes de corte, a fim de se reduzir a presença de bactérias resistentes e produtoras de ESBL e evitar sua disseminação para o meio ambiente, ovos férteis e frangos de corte e, consequentemente, carne de frango e humanos.

Lesões de Tuberculose Bovina em Abatedouros-Frigoríficos no Brasil: bibliometria

Salmonellosis is a globally important zoonosis, and Salmonella Heidelberg is one of the most prevalent serovars in poultry production worldwide, as well as in food poisoning cases. Antimicrobial drugs were previously widely used to face health challenges in animal production; however, since their ban as performance enhancers, many alternative strategies have been proposed. One of these strategies is the use of plant extracts, such as those containing the alkaloids benzophenanthridine and protopine. These compounds have antimicrobial, anti-inflammatory, immunomodulation, and nutritional effects. The objective of the present study was to evaluate the effects of the supply of a product containing benzophenanthridine and protopine (Sangrovit(r)WS 100 g/1000 L of drinking water) to broilers during different rearing periods 1-21, 1-6 and 6-21 days of age challenged or not with Salmonella Heidelberg at six days of age. There was no effect of the product on the performance, jejunal morphometry, cecal goblet cell counts, or control of Salmonella spp. in broilers challenged or not with Salmonella Heidelberg. However, the group receiving the alkaloids from 1 to 21 days of age, compared with the control group, presented a numerical difference of 28 points in productive efficiency index, which directly impacts live production cost of live broiler, representing savings of R$ 0.11/kg of meat produced.