Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Activité antifongique et antimycotoxines d’huiles essentielles tunisiennes sur des souches de Fusarium productrices d'enniatines et évaluation de leur potentialisation par nanoencapsulation

Mycotoxins are toxic secondary metabolites that accumulate in food matrices. They are produced by several genera of filamentous fungi. Contamination of crops by these fungi results in significant economic loss and contamination by their mycotoxins presents a significant hazard to animal and human health. An increase in the occurrence of "emerging mycotoxins" has been recorded worldwide during the last decade. This term includes mycotoxins that are not monitored or regulated. Enniatins (ENN) are one of the main groups of emerging mycotoxins. They are produced by several species of Fusarium that participate in Fusarium head blight of cereals, but are less studied than other Fusarium spp. In this work, batches of asymptomatic grains were analyzed for their mycotoxin content and the Fusarium spp. present, in order to better identify the risks of contamination of Tunisian wheat. In a lot contaminated with ENN, four isolates were obtained, two of which were ENN producers in vitro. Their morphological identification and analyses of DNA sequences confirmed their belonging to the Fusarium tricinctum species complex. One of the isolates named 33T was a F. acuminatum.To date, the different strategies to reduce Fusarium spp. infections and contamination by its mycotoxins in foodstuffs all over the world are not sufficiently effective and the development of alternative solutions has become a priority. The use of essential plant oils (EO) for the development of environmentally friendly plant fungicides has several advantages: relatively high volatility, biodegradability and consumer acceptance. We tested the efficacy of EOs from 8 Tunisian plants for their antifungal activity and inhibition of ENN accumulation on the 33T strain and a strain of F. avenaceum. The EOs of Ammoides pusilla and Thymus capitatus were selected, then their chemical composition characterized, and their biological activities studied in detail. The EOs limit the germination rate of conidia and the growth rate of mycelium whether they are in contact with the culture medium or through their volatile compounds. They also inhibit the synthesis of ENN. Thymol, the major compound in A. pusilla EO may be responsible for the antifungal activity but is not effective alone in inhibiting ENN synthesis.The low persistence and high sensitivity of EOs to oxidation and UV exposure limit their use in the free state in cultures. In order to improve the conditions of use and increase the applicability of natural bioactive formulations, encapsulation in nanocarriers is an emerging technology. A. pusilla EO was encapsulated in mesoporous silica nanoparticles (MSNPs) which exhibit high stability, biocompatibility, homogeneous porosity, high inertness and ease of functionalization. This treatment prolonged the diffusion time of volatile EO compounds into the environment and significantly increased fungistatic activity and inhibition of ENN accumulation for the same amount of EO used. MSNPs alone also limited ENN accumulation.This work was the first to identify F. acuminatum in grains in Tunisia and to characterize EOs inhibiting ENN production by F avenaceum and F. acuminatum. They open the way to future developments in the use of these EOs to control these fungi and their mycotoxins, in particular through their encapsulation in mesoporous silica.Les mycotoxines sont des métabolites secondaires toxiques qui s’accumulent dans les matrices alimentaires. Elles sont produites par plusieurs genres de champignons filamenteux. La contamination des cultures par ces champignons entraîne une perte économique significative et la contamination par leurs mycotoxines présente un danger important pour la santé animale et humaine. Une augmentation de l'occurrence des « mycotoxines émergentes » a été enregistrée dans le monde au cours de la dernière décennie. Ce terme inclut les mycotoxines qui ne sont ni surveillées ni soumises à une réglementation. Les enniatines (ENN) sont un des groupes principaux des mycotoxines émergentes. Elles sont produites par plusieurs espèces de Fusarium qui participent à la fusariose des épis de céréales, mais sont moins étudiées que d’autres Fusarium spp. Dans ce travail, des lots de grains asymptomatiques ont été analysés pour leurs teneurs en mycotoxine et les Fusarium spp. présents afin de mieux cerner les risques de contamination des blés tunisiens. Dans un lot contaminé en ENN, quatre isolats ont été obtenus, dont deux étaient des producteurs d’ENN in vitro. Leur identification morphologique et à partir de séquences d’ADN ont permis de confirmer leur appartenance au complexe d’espèce Fusarium tricinctum. L’un des isolats nommé 33T était un F. acuminatum.A ce jour les différentes stratégies mises en place pour réduire les infections par Fusarium spp. et la contamination par ses mycotoxines dans les denrées partout dans le monde ne sont suffisamment efficaces et le développement de solutions alternatives est devenu une priorité. L'utilisation d'huiles essentielles végétales (HE) pour l'élaboration de fongicides végétaux respectueux de l'environnement présente divers avantages : volatilité relativement élevée, caractère biodégradable et acceptation du consommateur. Nous avons testé l’efficacité d’HE issues de 8 plantes tunisiennes pour leur activité antifongique et d’inhibition de l’accumulation d’ENN sur la souche 33T et une souche de F. avenaceum. Les HE d’Ammoides pusilla et de Thymus capitatus ont été sélectionnées, puis leur composition chimique caractérisée, et leurs activités biologiques étudiées en détail. Les HE limitent le taux de germination des conidies et la vitesse de croissance du mycélium qu’elle soient en contact dans le milieu de culture ou par l’intermédiaire de leurs composés volatils. Elles inhibent aussi la synthèse des ENN. Le thymol, composé majoritaire de l’HE d’A. pusilla peut être responsable de l’activité antifongique mais n’est pas efficace seul pour inhiber la synthèse d’ENN.La faible persistance et la forte sensibilité des HE à l'oxydation et à l'exposition aux UV limitent leur utilisation à l'état libre en cultures. Afin d'améliorer les conditions d'utilisation et d'augmenter l'applicabilité des formulations bioactives naturelles, l'encapsulation dans des nano-supports est une technologie émergente. L’HE d’A. pusilla a été encapsulée dans des nanoparticules de silice mésoporeuse (MSNPs) qui présentent une stabilité élevée, une biocompatibilité, une porosité homogène, une inertie élevée et une facilité de fonctionnalisation. Ce traitement a permis de prolonger le temps de diffusion des composés volatils de l’HE dans l’environnement et a sensiblement augmenté l’activité fongistatique et l’inhibition de l’accumulation d’ENN pour une même quantité d’HE utilisée. Les MSNPs seules limitaient aussi l’accumulation d’ENN.Ces travaux ont été les premiers mettre en évidence F. acuminatum dans des grains en Tunisie et à caractériser des HE inhibant la production d’ENN par F avenaceum et F. acuminatum. Ils ouvrent la voie à des développements futurs d’utilisation de ces HE pour maitriser ces champignons et leurs mycotoxines, en particulier grâce leur encapsulation dans de la silice mésoporeuse

Antifungal and antimycotoxins activity of Tunisian essential oils against enniatin producing Fusarium strains and evaluation of their potentiation using nanoencapsulation

Les mycotoxines sont des métabolites secondaires toxiques qui s’accumulent dans les matrices alimentaires. Elles sont produites par plusieurs genres de champignons filamenteux. La contamination des cultures par ces champignons entraîne une perte économique significative et la contamination par leurs mycotoxines présente un danger important pour la santé animale et humaine. Une augmentation de l'occurrence des « mycotoxines émergentes » a été enregistrée dans le monde au cours de la dernière décennie. Ce terme inclut les mycotoxines qui ne sont ni surveillées ni soumises à une réglementation. Les enniatines (ENN) sont un des groupes principaux des mycotoxines émergentes. Elles sont produites par plusieurs espèces de Fusarium qui participent à la fusariose des épis de céréales, mais sont moins étudiées que d’autres Fusarium spp. Dans ce travail, des lots de grains asymptomatiques ont été analysés pour leurs teneurs en mycotoxine et les Fusarium spp. présents afin de mieux cerner les risques de contamination des blés tunisiens. Dans un lot contaminé en ENN, quatre isolats ont été obtenus, dont deux étaient des producteurs d’ENN in vitro. Leur identification morphologique et à partir de séquences d’ADN ont permis de confirmer leur appartenance au complexe d’espèce Fusarium tricinctum. L’un des isolats nommé 33T était un F. acuminatum.A ce jour les différentes stratégies mises en place pour réduire les infections par Fusarium spp. et la contamination par ses mycotoxines dans les denrées partout dans le monde ne sont suffisamment efficaces et le développement de solutions alternatives est devenu une priorité. L'utilisation d'huiles essentielles végétales (HE) pour l'élaboration de fongicides végétaux respectueux de l'environnement présente divers avantages : volatilité relativement élevée, caractère biodégradable et acceptation du consommateur. Nous avons testé l’efficacité d’HE issues de 8 plantes tunisiennes pour leur activité antifongique et d’inhibition de l’accumulation d’ENN sur la souche 33T et une souche de F. avenaceum. Les HE d’Ammoides pusilla et de Thymus capitatus ont été sélectionnées, puis leur composition chimique caractérisée, et leurs activités biologiques étudiées en détail. Les HE limitent le taux de germination des conidies et la vitesse de croissance du mycélium qu’elle soient en contact dans le milieu de culture ou par l’intermédiaire de leurs composés volatils. Elles inhibent aussi la synthèse des ENN. Le thymol, composé majoritaire de l’HE d’A. pusilla peut être responsable de l’activité antifongique mais n’est pas efficace seul pour inhiber la synthèse d’ENN.La faible persistance et la forte sensibilité des HE à l'oxydation et à l'exposition aux UV limitent leur utilisation à l'état libre en cultures. Afin d'améliorer les conditions d'utilisation et d'augmenter l'applicabilité des formulations bioactives naturelles, l'encapsulation dans des nano-supports est une technologie émergente. L’HE d’A. pusilla a été encapsulée dans des nanoparticules de silice mésoporeuse (MSNPs) qui présentent une stabilité élevée, une biocompatibilité, une porosité homogène, une inertie élevée et une facilité de fonctionnalisation. Ce traitement a permis de prolonger le temps de diffusion des composés volatils de l’HE dans l’environnement et a sensiblement augmenté l’activité fongistatique et l’inhibition de l’accumulation d’ENN pour une même quantité d’HE utilisée. Les MSNPs seules limitaient aussi l’accumulation d’ENN.Ces travaux ont été les premiers mettre en évidence F. acuminatum dans des grains en Tunisie et à caractériser des HE inhibant la production d’ENN par F avenaceum et F. acuminatum. Ils ouvrent la voie à des développements futurs d’utilisation de ces HE pour maitriser ces champignons et leurs mycotoxines, en particulier grâce leur encapsulation dans de la silice mésoporeuse.Mycotoxins are toxic secondary metabolites that accumulate in food matrices. They are produced by several genera of filamentous fungi. Contamination of crops by these fungi results in significant economic loss and contamination by their mycotoxins presents a significant hazard to animal and human health. An increase in the occurrence of "emerging mycotoxins" has been recorded worldwide during the last decade. This term includes mycotoxins that are not monitored or regulated. Enniatins (ENN) are one of the main groups of emerging mycotoxins. They are produced by several species of Fusarium that participate in Fusarium head blight of cereals, but are less studied than other Fusarium spp. In this work, batches of asymptomatic grains were analyzed for their mycotoxin content and the Fusarium spp. present, in order to better identify the risks of contamination of Tunisian wheat. In a lot contaminated with ENN, four isolates were obtained, two of which were ENN producers in vitro. Their morphological identification and analyses of DNA sequences confirmed their belonging to the Fusarium tricinctum species complex. One of the isolates named 33T was a F. acuminatum.To date, the different strategies to reduce Fusarium spp. infections and contamination by its mycotoxins in foodstuffs all over the world are not sufficiently effective and the development of alternative solutions has become a priority. The use of essential plant oils (EO) for the development of environmentally friendly plant fungicides has several advantages: relatively high volatility, biodegradability and consumer acceptance. We tested the efficacy of EOs from 8 Tunisian plants for their antifungal activity and inhibition of ENN accumulation on the 33T strain and a strain of F. avenaceum. The EOs of Ammoides pusilla and Thymus capitatus were selected, then their chemical composition characterized, and their biological activities studied in detail. The EOs limit the germination rate of conidia and the growth rate of mycelium whether they are in contact with the culture medium or through their volatile compounds. They also inhibit the synthesis of ENN. Thymol, the major compound in A. pusilla EO may be responsible for the antifungal activity but is not effective alone in inhibiting ENN synthesis.The low persistence and high sensitivity of EOs to oxidation and UV exposure limit their use in the free state in cultures. In order to improve the conditions of use and increase the applicability of natural bioactive formulations, encapsulation in nanocarriers is an emerging technology. A. pusilla EO was encapsulated in mesoporous silica nanoparticles (MSNPs) which exhibit high stability, biocompatibility, homogeneous porosity, high inertness and ease of functionalization. This treatment prolonged the diffusion time of volatile EO compounds into the environment and significantly increased fungistatic activity and inhibition of ENN accumulation for the same amount of EO used. MSNPs alone also limited ENN accumulation.This work was the first to identify F. acuminatum in grains in Tunisia and to characterize EOs inhibiting ENN production by F avenaceum and F. acuminatum. They open the way to future developments in the use of these EOs to control these fungi and their mycotoxins, in particular through their encapsulation in mesoporous silica

Antifungal and antimycotoxins activity of Tunisian essential oils against enniatin producing Fusarium strains and evaluation of their potentiation using nanoencapsulation

Les mycotoxines sont des métabolites secondaires toxiques qui s’accumulent dans les matrices alimentaires. Elles sont produites par plusieurs genres de champignons filamenteux. La contamination des cultures par ces champignons entraîne une perte économique significative et la contamination par leurs mycotoxines présente un danger important pour la santé animale et humaine. Une augmentation de l'occurrence des « mycotoxines émergentes » a été enregistrée dans le monde au cours de la dernière décennie. Ce terme inclut les mycotoxines qui ne sont ni surveillées ni soumises à une réglementation. Les enniatines (ENN) sont un des groupes principaux des mycotoxines émergentes. Elles sont produites par plusieurs espèces de Fusarium qui participent à la fusariose des épis de céréales, mais sont moins étudiées que d’autres Fusarium spp. Dans ce travail, des lots de grains asymptomatiques ont été analysés pour leurs teneurs en mycotoxine et les Fusarium spp. présents afin de mieux cerner les risques de contamination des blés tunisiens. Dans un lot contaminé en ENN, quatre isolats ont été obtenus, dont deux étaient des producteurs d’ENN in vitro. Leur identification morphologique et à partir de séquences d’ADN ont permis de confirmer leur appartenance au complexe d’espèce Fusarium tricinctum. L’un des isolats nommé 33T était un F. acuminatum.A ce jour les différentes stratégies mises en place pour réduire les infections par Fusarium spp. et la contamination par ses mycotoxines dans les denrées partout dans le monde ne sont suffisamment efficaces et le développement de solutions alternatives est devenu une priorité. L'utilisation d'huiles essentielles végétales (HE) pour l'élaboration de fongicides végétaux respectueux de l'environnement présente divers avantages : volatilité relativement élevée, caractère biodégradable et acceptation du consommateur. Nous avons testé l’efficacité d’HE issues de 8 plantes tunisiennes pour leur activité antifongique et d’inhibition de l’accumulation d’ENN sur la souche 33T et une souche de F. avenaceum. Les HE d’Ammoides pusilla et de Thymus capitatus ont été sélectionnées, puis leur composition chimique caractérisée, et leurs activités biologiques étudiées en détail. Les HE limitent le taux de germination des conidies et la vitesse de croissance du mycélium qu’elle soient en contact dans le milieu de culture ou par l’intermédiaire de leurs composés volatils. Elles inhibent aussi la synthèse des ENN. Le thymol, composé majoritaire de l’HE d’A. pusilla peut être responsable de l’activité antifongique mais n’est pas efficace seul pour inhiber la synthèse d’ENN.La faible persistance et la forte sensibilité des HE à l'oxydation et à l'exposition aux UV limitent leur utilisation à l'état libre en cultures. Afin d'améliorer les conditions d'utilisation et d'augmenter l'applicabilité des formulations bioactives naturelles, l'encapsulation dans des nano-supports est une technologie émergente. L’HE d’A. pusilla a été encapsulée dans des nanoparticules de silice mésoporeuse (MSNPs) qui présentent une stabilité élevée, une biocompatibilité, une porosité homogène, une inertie élevée et une facilité de fonctionnalisation. Ce traitement a permis de prolonger le temps de diffusion des composés volatils de l’HE dans l’environnement et a sensiblement augmenté l’activité fongistatique et l’inhibition de l’accumulation d’ENN pour une même quantité d’HE utilisée. Les MSNPs seules limitaient aussi l’accumulation d’ENN.Ces travaux ont été les premiers mettre en évidence F. acuminatum dans des grains en Tunisie et à caractériser des HE inhibant la production d’ENN par F avenaceum et F. acuminatum. Ils ouvrent la voie à des développements futurs d’utilisation de ces HE pour maitriser ces champignons et leurs mycotoxines, en particulier grâce leur encapsulation dans de la silice mésoporeuse.Mycotoxins are toxic secondary metabolites that accumulate in food matrices. They are produced by several genera of filamentous fungi. Contamination of crops by these fungi results in significant economic loss and contamination by their mycotoxins presents a significant hazard to animal and human health. An increase in the occurrence of "emerging mycotoxins" has been recorded worldwide during the last decade. This term includes mycotoxins that are not monitored or regulated. Enniatins (ENN) are one of the main groups of emerging mycotoxins. They are produced by several species of Fusarium that participate in Fusarium head blight of cereals, but are less studied than other Fusarium spp. In this work, batches of asymptomatic grains were analyzed for their mycotoxin content and the Fusarium spp. present, in order to better identify the risks of contamination of Tunisian wheat. In a lot contaminated with ENN, four isolates were obtained, two of which were ENN producers in vitro. Their morphological identification and analyses of DNA sequences confirmed their belonging to the Fusarium tricinctum species complex. One of the isolates named 33T was a F. acuminatum.To date, the different strategies to reduce Fusarium spp. infections and contamination by its mycotoxins in foodstuffs all over the world are not sufficiently effective and the development of alternative solutions has become a priority. The use of essential plant oils (EO) for the development of environmentally friendly plant fungicides has several advantages: relatively high volatility, biodegradability and consumer acceptance. We tested the efficacy of EOs from 8 Tunisian plants for their antifungal activity and inhibition of ENN accumulation on the 33T strain and a strain of F. avenaceum. The EOs of Ammoides pusilla and Thymus capitatus were selected, then their chemical composition characterized, and their biological activities studied in detail. The EOs limit the germination rate of conidia and the growth rate of mycelium whether they are in contact with the culture medium or through their volatile compounds. They also inhibit the synthesis of ENN. Thymol, the major compound in A. pusilla EO may be responsible for the antifungal activity but is not effective alone in inhibiting ENN synthesis.The low persistence and high sensitivity of EOs to oxidation and UV exposure limit their use in the free state in cultures. In order to improve the conditions of use and increase the applicability of natural bioactive formulations, encapsulation in nanocarriers is an emerging technology. A. pusilla EO was encapsulated in mesoporous silica nanoparticles (MSNPs) which exhibit high stability, biocompatibility, homogeneous porosity, high inertness and ease of functionalization. This treatment prolonged the diffusion time of volatile EO compounds into the environment and significantly increased fungistatic activity and inhibition of ENN accumulation for the same amount of EO used. MSNPs alone also limited ENN accumulation.This work was the first to identify F. acuminatum in grains in Tunisia and to characterize EOs inhibiting ENN production by F avenaceum and F. acuminatum. They open the way to future developments in the use of these EOs to control these fungi and their mycotoxins, in particular through their encapsulation in mesoporous silica

Mesoporous silica nanoparticles for the encapsulation of essential oils and the improvement of their activity against Fusasrium avenaceum and its production of enniatins

International audienceDespite the in vitro efficacy of various essential oils (EOs), their practical use to control toxigenic Fusarium spp is limited by their high volatility and sensitivity to UV and oxidation. Their nano-encapsulation can provide protection for the active volatile molecules and allow for a gradual release into the environment. Mesoporous silica nanoparticles (MSNPs) are inert, mechanically stable, stable in suspension in an aqueous medium and their specific surface area is very suitable for functionalization. We have used them for the encapsulation of EOs with antifungal and antimycotoxin activity Mesoporous silica nanoparticles synthesis tetraethyl orthosilicate (TEOS

Caractérisation de Fusarium acuminatum: un producteur potentiel d'énniatines dans les blés Tunisiens

International audienceFusarium Head Blight (FHB), caused by multiple species of Fusarium in small grain cereals, is a significant and long-standing problem anywhere in the world. Knowing regional Fusarium spp. present on non-symptomatic grains and their potential for mycotoxin production is of concern for identifying novel actions for FHB and mycotoxin management, such as treatments with essential oils. Analyzing the mycotoxin content of grains from non-symptomatic ears of different wheat varieties cultivated in Tunisia, we isolated Fusaria specimens identified as F. culmorum and F. acuminatum using analysis of the partial DNA sequence of the β-tubulin gene and ITS region. Two isolates of the latter species, uncommon in cereal grains in this region until now, were shown to be effective producers of enniatins in vitro, with 1390 and 3089 μg g −1 mycelial biomass (dry) in 11-day-old cultures. The susceptibility of an isolate of F. acuminatum to the fungistatic and antimycotoxin effects of eight essential oils was measured. Essential oils from Ammoides pusilla and Thymus capitatus used at 0.1 μL mL −1 in an agar culture medium, affected the mycelial growth by 55% and 79%, respectively and reduced the accumulation of enniatins per unit of mycelial colony by 26% and 52%, respectively. Finally, F. acuminatum was shown to be a contaminant of wheat grains in Tunisia and it may contribute to the contamination in enniatins. Two essential oils of Tunisian plants could be used for developing a biofungicide limiting both its mycelial growth and its accumulation of mycotoxins in grains

Tunisian thyme essential iol for controlling enniatins producing fusarium species

International audienceEnniatins are emerging mycotoxins produced by Fusarium species. They are frequently found as contaminants in cereal grains in recent years. The synthesis of these secondary metabolites is often a response to biotic and abiotic stresses. Therefore, the introduction of fungicides into the environment of toxigenic fungi can lead to an increase in mycotoxin accumulation. The search for molecules with both antifungal and antimycotoxigenic activities is a challenge to preserve food safety. Essential oils (EOs) have a promising potential as natural fungicides and should be used both to control fungi and/or their mycotoxin production. In the present work, we extracted the essential oil of Tunisian Thymus capitatus and tested its effect in vitro on two enniatin-producing Fusarium strains when placed in contact with the mycelium in solid medium or used as a fumigant. In agar medium, contact tests measured with two different sets of EOs for a strain of Fusarium avenaceum provided an IC 5O of 0.05 µL EO mL-1. For another strain of Fusarium sp. it was found an IC 50 of 0.08 µL EO mL-1. Fungistatic activity induced no overproduction of enniatins and in contrast, decreases of 55% were found in some samples. Volatile components diffusing in a sealed container also had fungistatic activity that was both dose (5 to 25 µL 1.5 L-1) and time (6 to 24 days) dependent. No fungal acclimation to the EOs and no persistent effect of the EOs were observed, but the decrease in protective effect with increasing incubation time was probably due to EOs alterations

TUNISIAN THYME ESSENTIAL OIL FOR CONTROLLING ENNIATINS PRODUCING FUSARIUM SPECIES

Enniatins are emerging mycotoxins produced by Fusarium species. They are frequently found as contaminants in cereal grains in recent years. The synthesis of these secondary metabolites is often a response to biotic and abiotic stresses. Therefore, the introduction of fungicides into the environment of toxigenic fungi can lead to an increase in mycotoxin accumulation. The search for molecules with both antifungal and antimycotoxigenic activities is a challenge to preserve food safety. Essential oils (EOs) have a promising potential as natural fungicides and should be used both to control fungi and/or their mycotoxin production. In the present work, we extracted the essential oil of Tunisian Thymus capitatus and tested its effect in vitro on two enniatin-producing Fusarium strains when placed in contact with the mycelium in solid medium or used as a fumigant. In agar medium, contact tests measured with two different sets of EOs for a strain of Fusarium avenaceum provided an IC5O of 0.05 μL EO mL-1. For another strain of Fusarium sp. it was found an IC50 of 0.08 μL EO mL-1. Fungistatic activity induced no overproduction of enniatins and in contrast, decreases of 55% were found in some samples. Volatile components diffusing in a sealed container also had fungistatic activity that was both dose (5 to 25 μL 1.5 L-1) and time (6 to 24 days) dependent. No fungal acclimation to the EOs and no persistent effect of the EOs were observed, but the decrease in protective effect with increasing incubation time was probably due to EOs alterations

Encapsulation of <i>Ammoides pusila</i> Essential Oil into Mesoporous Silica Particles for the Enhancement of Their Activity against <i>Fusarium avenaceum</i> and Its Enniatins Production

Essential oils (EOs) that have antifungal activity and mycotoxin reduction ability are candidates to develop bioactive alternatives and environmentally friendly treatment against Fusarium species in cereals. However, their practical use is facing limitations such as high volatility, UV sensitivity, and fast oxidation. Encapsulation techniques are supposed to provide protection to the EOs and control their release into the environment. Ammoides pusilla essential oil (AP-EO) proved to be an efficient inhibitor of Fusarium avenaceum growth and its enniatins (ENNs) production. In the present work, AP-EO was encapsulated, using the impregnation method, into mesoporous silica particles (MSPs) with narrow slit pores (average diameter = 3.1 nm) and coated with chitosan. In contact assays using an agar medium, the antifungal activity of AP-EO at 0.1 µL mL−1 improved by three times when encapsulated into MSPs without chitosan and the ENNs production was significantly inhibited both in coated and non-coated MSPs. Controls of MSPs also inhibited the ENNs production without affecting the mycelial growth. In fumigation experiments assessing the activity of the EO volatile compounds, encapsulation into MSPs improved significantly both the antifungal activity and ENNs inhibition. Moreover, coating with chitosan stopped the release of EO. Thus, encapsulation of an EO into MSPs improving its antifungal and antimycotoxin properties is a promising tool for the formulation of a natural fungicide that could be used in the agriculture or food industry to protect plant or food products from the contamination by toxigenic fungi such as Fusarium sp. and their potential mycotoxins

Ammoides pusilla Essential Oil: A Potent Inhibitor of the Growth of Fusarium avenaceum and Its Enniatin Production

International audienceEnniatins are mycotoxins produced by Fusarium species contaminating cereals and various agricultural commodities. The co-occurrence of these mycotoxins in large quantities with other mycotoxins such as trichothecenes and the possible synergies in toxicity could lead to serious food safety problems. Using the agar dilution method, Ammoides pusilla was selected among eight Tunisian plants for the antifungal potential of its essential oil (EO) on Fusarium avenaceum mycelial growth and its production of enniatins. Two EO batches were produced and analyzed by GC/MS-MS. Their activities were measured using both contact assays and fumigant tests (estimated IC50 were 0.1 µL·mL−1 and 7.6 µL·L−1, respectively). The A. pusilla EOs and their volatiles inhibited the germination of spores and the mycelial growth, showing a fungistatic but not fungicidal activity. The accumulation of enniatins was also significantly reduced (estimated IC50 were 0.05 µL·mL−1 for the contact assays and 4.2 µL·L−1 for the fumigation assays). The most active batch of EO was richer in thymol, the main volatile compound found. Thymol used as fumigant showed a potent fungistatic activity but not a significant antimycotoxigenic activity. Overall, our data demonstrated the bioactivity of A. pusilla EO and its high potential to control F. avenaceum and its enniatins production in agricultural commodities