Phenotypic and genotypic comparison of antimicrobial-resistant variants of Escherichia coli and Salmonella Typhimurium isolated from evolution assays with antibiotics or commercial products based on essential oils

On account of the widespread development and propagation of antimicrobial-resistant (AMR) bacteria, essential oils (EOs) have emerged as potential alternatives to antibiotics. However, as already observed for antibiotics, recent studies have raised concerns regarding the potential emergence of resistant variants (RVs) to EOs. In this study, we assessed the emergence of RVs in Escherichia coli and Salmonella enterica Typhimurium after evolution assays under extended exposure to subinhibitory doses of two commercial EOs (AEN and COLIFIT) as well as to two antibiotics (amoxicillin and colistin). Phenotypic characterization of RVs from evolution assays with commercial EOs yielded no relevant increases in the minimum inhibitory concentration (MIC) of E. coli and did not even modify MIC values in S. Typhimurium. Conversely, RVs of E. coli and S. Typhimurium isolated from evolution assays with antibiotics showed increased resistance. Genotypic analysis demonstrated that resistance to commercial EOs was associated with enhanced protection against oxidative stress and redirection of cell energy toward efflux activity, while resistance to antibiotics was primarily linked to modifications in the cell binding sites of antibiotics. These findings suggest that AEN and COLIFIT could serve as safe alternatives to antibiotics in combating the emergence and dissemination of antimicrobial resistance within the agrifood system

An antimethanogenic index for meadow plants consumed by ruminants

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In vitro antiprotozoal action of 7 spices, medicinal plants and essential oils against 3 stages of Eimeria tenella

International audienceGrowing societal concerns to replace coccidiostats in poultry farms lead to the use of alternatives as plant bio-actives. To investigate natural molecules modes of action we designed this in vitro study to screen anti-protozoal activity of 4 spices or medicinal plants described by non-volatile active molecules (MedP) (Fabacea powder, Urticaceae extract, Punicaceae extract, Acanthaceae extract) and 3 essentials oils (EO) (Lilaceae EO, Lamiaceae EO, Lauraceae EO) against 3 different stages of E. tenella.First, cytotoxicity of samples was evaluated using MTS test against MDBK cells. The lowest dilution of each MedP or EO samples showing no cytotoxicity (lethal dose 10%) was used to perform 3 antiprotozoal tests. Sporozoite viability test was conducted in triplicate with Evans blue dye (incubation 41°C for 1h). Invasion inhibition test was performed in 96 microplate: 1.5×104 MDBK cells,infected with sporozoites (MOI = 1), were incubated with each sample (4 replicates) at 41°C. E. tenella strain expressed an enzymatic activity which can be quantify. After 2h, substrate was added and enzymatic reaction measured after 2h incubation at 37°C. Invasion rate was calculated as percentage of samples respective absorbance compared to absorbance of control. Finally, 5 ×105 non sporulated oocysts were incubated in triplicate with each MedP or each EO samples in solution of potassium dichromate (2%) at 26°C for 72h. Sporulation rate was defined as percentage of sporulated oocysts intested samples compared to sporulated oocysts in control. Mann-Whitney test was used to compare each sample rate to control. The 4 MedP samples were less cytotoxic than 3 EO samples (MedP dilutedat 10-2, EO diluted at 10-4-10-6). MedP samples showed antiprotozoal activity against different E. tenella stages: sporozoites viability rate were between 76.2% and 27% (p = 0.05). Urticaeae extract showed also a sporulation rate of 68.8% (p=0.05). Punicaceae extract exhibited invasion rate of 74% (p<0.001) and sporulation rate of 81.6% (p=0.05). EOs showed only direct anti sporozoites activity (sporozoites viability rates between 76.7% and 81.6% (p=0.05)). MedP group showed antiprotozoal activity againstdifferent E. tenella stages, on the contrary of EOs, which only targeted sporozoites. Thisstudy helps to understand how bio-actives plants could act in association to reduce E. tenella pathogenicity

Association rule mining to help detect plant phenolic compounds putatively involved in decreased ruminal methane production in vitro

National audienc

Association rule mining to help detect plant phenolic compounds putatively involved in decreased ruminal methane production in vitro: In the virgin forest of unknown bioactive plant phenolic compounds, association rules work like bushcutters clearing pathways to help discover active compounds

International audienceIntroduction In the search for natural alternatives to synthetic chemicals able to mitigate methane emission by ruminants, bioactive plant secondary metabolites are valuable candidates. However, these phytochemicals come in myriad chemical structures, and any one plant may contain hundreds of them. Even in plant extracts containing tannins, saponins or essential oils, it is difficult to link the presence of a compound or combination to the plant's activity. Here we focus on low-molecular-weight (0.5) were discarded before data mining to avoid false-positives. With the minimum thresholds of 5 for S and 0.5 for C, there were 205 candidate peaks. In a first strategy, results were filtered via the constraints of a) co-occurrence of the peak in the 280 and 320 nm matrices and b) C > 0.65, which narrowed the candidate peaks down to 28. In a second strategy, the constraints were that the peaks had to be major (i.e. more than 10 times the area of the median peak) and present in the plants that showed high antimethanogenic effect (outliers), which narrowed the candidate peaks down to 24. Combining the two strategies resulted in 7 candidate peaks. One peak was easily identified as gallic acid. Based on absorbance spectrum between 200 and 400 nm, three others were cinnamic acid derivatives and two were flavonols. Conclusion Association rules mining was able to select a compact number of peaks making identification feasible. The effect of these pure compounds now has to be verified for proof of the concept. While the algorithm works with qualitative data, using strategy which selects among the major peaks of the profiles serves to integrate the quantitative aspect. Acknowledgements We thank ethnobotanist G. Lalière and the Conservatoire Botanique National du Massif Central for plant collection

Association rule mining to help detect plant phenolic compounds putatively involved in decreased ruminal methane production in vitro: In the virgin forest of unknown bioactive plant phenolic compounds, association rules work like bushcutters clearing pathways to help discover active compounds

International audienceIntroduction In the search for natural alternatives to synthetic chemicals able to mitigate methane emission by ruminants, bioactive plant secondary metabolites are valuable candidates. However, these phytochemicals come in myriad chemical structures, and any one plant may contain hundreds of them. Even in plant extracts containing tannins, saponins or essential oils, it is difficult to link the presence of a compound or combination to the plant's activity. Here we focus on low-molecular-weight (0.5) were discarded before data mining to avoid false-positives. With the minimum thresholds of 5 for S and 0.5 for C, there were 205 candidate peaks. In a first strategy, results were filtered via the constraints of a) co-occurrence of the peak in the 280 and 320 nm matrices and b) C > 0.65, which narrowed the candidate peaks down to 28. In a second strategy, the constraints were that the peaks had to be major (i.e. more than 10 times the area of the median peak) and present in the plants that showed high antimethanogenic effect (outliers), which narrowed the candidate peaks down to 24. Combining the two strategies resulted in 7 candidate peaks. One peak was easily identified as gallic acid. Based on absorbance spectrum between 200 and 400 nm, three others were cinnamic acid derivatives and two were flavonols. Conclusion Association rules mining was able to select a compact number of peaks making identification feasible. The effect of these pure compounds now has to be verified for proof of the concept. While the algorithm works with qualitative data, using strategy which selects among the major peaks of the profiles serves to integrate the quantitative aspect. Acknowledgements We thank ethnobotanist G. Lalière and the Conservatoire Botanique National du Massif Central for plant collection

Effect of Plant Bioactive Compounds Supplemented in Transition Dairy Cows on the Metabolic and Inflammatory Status

(1) Background: This study evaluated the effects of a plant bioactive (Phyto Ax&rsquo;Cell, Phytosynthese, Mozac, France) on the inflammatory status and health of dairy cows during calving. (2) Methods: 46 Holstein crossbred cows were randomized into a control group (CON, n = 23) and the Phyto Ax&rsquo;Cell group (PAC, n = 23). PAC received Phyto Ax&rsquo;Cell at 25 g/cow/day, from 15 days prepartum to 7 days postpartum. Blood analyses were performed weekly from D-7 to D14 to evaluate the energy metabolism and inflammatory status; rectal temperature was measured daily within 14 days from calving day (D0). (3) Results: PAC showed lower serum haptoglobin at D7 (0.55 vs. 0.79 mg/mL; p &lt; 0.05) and D14 (0.44 vs. 0.66 mg/mL; p &lt; 0.05). CON had a higher number of circulating white blood cells and granulocytes on D7 (p &lt; 0.05). Fewer cows from PAC showed hyperthermia (&ge;39 &deg;C) during the first 2 weeks postpartum (&minus;7%, p &lt; 0.05). Energy metabolism, which was represented by the NEFA/cholesterol ratio, improved (0.21 vs. 0.36 at D0, p &lt; 0.1; 0.19 and 0.15 vs. 0.36 and 0.32, respectively, at D+7 and D+14, p &lt; 0.05) under the plant bioactive supplementation. (4) Conclusions: The results suggest that the anti-inflammatory plant bioactive compound with Brazilian green propolis administered during calving had a beneficial effect on the energy and inflammatory status of dairy cows

Effectiveness of two plant-based in-feed additives against an escherichia coli f4 oral challenge in weaned piglets

This study evaluates the efficacy of two plant-based feed supplementations to fight coliba-cillosis in weanlings. A total of 96 piglets (32 pens) were assigned to four diets: a control diet (T1) or supplemented with ZnO (2500 ppm Zn) (T2) or two different plant supplements, T3 (1 kg/t; based on essential oils) and T4 (T3 + 1.5 kg/t based on non-volatile compounds). After one week, animals were challenged with ETEC F4, and 8 days after, one animal per pen was euthanized. Performance, clinical signs, microbial analysis, inflammatory response, intestinal morphology, and ileal gene expression were assessed. ZnO improved daily gains 4 days after challenge, T3 and T4 showing intermediate values (96, 249, 170, and 157 g/d for T1, T2, T3, and T4, p = 0.035). Fecal lactobacilli were higher with T3 and T4 compared to ZnO (7.55, 6.26, 8.71, and 8.27 cfu/gFM; p = 0.0007) and T3 increased the lacto-bacilli/coliforms ratio (p = 0.002). T4 was associated with lower levels of Pig-MAP (p = 0.07) and increases in villus/crypt ratio (1.49, 1.90, 1.73, and 1.84; p = 0.009). Moreover, T4 was associated with an upregulation of the REG3G gene (p = 0.013; pFDR = 0.228) involved in the immune response induced by enteric pathogens. In conclusion, both plant supplements enhanced animal response in front of an ETEC F4 challenge probably based on different modes of action