Search

The foodborne pathogen, Listeria monocytogenes, (Lm), frequently undergoes selection pressure associated with the extensive use of disinfectants, such as quaternary ammonium compounds, which are widely used in food processing plants. The repeated exposure to sub-inhibitory biocide concentrations can induce increased tolerance to these compounds, but can also trigger the development of antibiotic resistance, and both increase the risk of food contamination and persistence in food production environments. Although the acquisition of genes can explain biocide tolerance, the genetic mechanisms underlying the adaptive cross-resistance to antibiotics remain unclear. We previously showed that repeated exposure to benzalkonium chloride (BC) and didecyldimethyl ammonium chloride (DDAC) led to reduced susceptibility to ciprofloxacin in Lm strains from diverse sources. Here, we compared the genomes of 16 biocide-adapted and 10 parental strains to identify the molecular mechanisms of fluoroquinolone cross-resistance. A core genome SNP analysis identified various mutations in the transcriptional regulator fepR (lmo2088) for 94% of the adapted strains and mutations in other effectors at a lower frequency. FepR is a local repressor of the MATE fluoroquinolone efflux pump FepA. The impact of the mutations on the structure and function of the protein was assessed by performing in silico prediction and protein homology modeling. Our results show that 75% of the missense mutations observed in fepR are located in the HTH domain of the protein, within the DNA interaction site. These mutations are predicted to reduce the activity of the regulator, leading to the overexpression of the efflux pump responsible for the ciprofloxacin-enhanced resistance.

Cet article présente une revue de la littérature concernant les opérations de désinfection appliquées dans les réseaux intérieurs, en particulier des établissements recevant du public y compris les établissements de santé, dans le but de maîtriser préventivement une éventuelle prolifération microbienne en régime continu ou d’assainir ledit réseau en cas de colonisation importante. Cette contamination microbienne peut concerner les réseaux tant d’eau froide que d’eau chaude. Nous étudierons successivement les raisons de l’utilisation de ces procédés, la désinfection chimique puis la désinfection thermique avec leur mise en œuvre technique, les résultats obtenus et leurs limites avant d’aborder en discussion la conception d’un réseau évitant la répétition d’opérations curatives peu efficaces puis de présenter des conclusions.

One Health European Joint Programme is acknowledged for the funding of the ListAdapt project and the support of A.G.’s postdoctoral fellowship. Laurent Guillier is acknowledged for his participation in the supervision of the ListAdapt project.; International audience; In this contribution, the antimicrobial susceptibility toward 11 antibiotics and four biocides of a panel of 205 Listeria monocytogenes (Lm) strains isolated from different ecological niches (i.e., food, animals and natural environment) was evaluated. The impact of exposure to biocides on the antibiotic susceptibilities of Lm was also investigated. Lm strains isolated from food exhibited overall a lower susceptibility (higher minimal inhibitory concentrations, MIC) for ammonium quaternary compounds (QACs) and peracetic acid (PAC) than strains isolated from animals and natural environments. Conversely, the ecological origins of Lm strains did not significantly affect their susceptibilities towards antibiotics. Interestingly, repeated exposure to QACs recurrently led to a decrease in susceptibility toward ciprofloxacin (CIP), a fluoroquinolone antibiotic, largely used in human medicine. Moreover, these lower levels of susceptibility to CIP remained stable in most Lm strains even after subcultures without biocide selection pressure, suggesting an adaptation involving modifications at the genetic level. Results underlined the ability of Lm to adapt to biocides, especially QACs, and the potential link between this adaptation and the selection of resistance toward critical antibiotics such as ciprofloxacin. These data support a potential role of the extensive use of QACs from “farm to fork” in the selection of biocide and antibiotic resistance in pathogenic bacteria such as Lm.

Les ammoniums quaternaires sont des substances aux propriétés tensio-actives et bactériostatiques largement utilisées au quotidien, dans des produits de nettoyage, des désinfectants et de nombreux produits cosmétiques. L’exposition professionnelle aux ammoniums quaternaires est à l’origine de pathologies respiratoires et dermatologiques comme l’asthme et la dermatite de contact. L’hypothèse de l'étude IMMUQUAP est qu’il est possible de se sensibiliser aux molécules d’AQ présentes dans les produits d’usage courant et de développer par la suite des pathologies allergiques.

National audience; Les ammoniums quaternaires sont des substances aux propriétés tensio-actives et bactériostatiques largement utilisées au quotidien, dans des produits de nettoyage, des désinfectants et de nombreux produits cosmétiques. L’exposition professionnelle aux ammoniums quaternaires est à l’origine de pathologies respiratoires et dermatologiques comme l’asthme et la dermatite de contact. L’hypothèse de l'étude IMMUQUAP est qu’il est possible de se sensibiliser aux molécules d’AQ présentes dans les produits d’usage courant et de développer par la suite des pathologies allergiques.

International audience; Biocide disinfectants are used in agro-food industries in order to limit the development of pathogens present in environment or on surfaces in contact with food for human or animal consumption. Biocide residues remaining on food surfaces may constitute a toxicological risk for the consumer. Very little feedback from the field on the rates of biocide residues in the industry exist due to a lack of simple, fast and responsive self-checking methods. The development of biosensors for the detection of biocide disinfectants represents a promising way to explore this, but most of this research remains limited.

A novel and reliable method to quantify residual levels of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in dairy products using ion-pairing reversed-phase liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed and fully validated. Sample extraction was done with salting-out technique using acetonitrile and sodium chloride. For LC–MS/MS, the analyte was detected using positive electrospray ionization (ESI+) and two multiple reaction monitoring (MRM) transitions were monitored. The method was validated in the 5–150 µg kg−1 range using total error approach. Thus, performance criteria of the method were evaluated. Relative standard deviations for trueness and precision were lower than 10%; with the exception of hard pressed cheese at 5 µg kg−1 for precision. The limit of quantification (LOQ) was around 5–7 µg kg−1 depending on the matrix of interest. The method was successfully applied to accurately quantify N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in 146 various dairy products with a maximum contamination level of 225 µg kg−1 in cheese.

Aims Our aim was to assess the effects of step-wise exposure to didecyl dimethyl ammonium chloride (DDAC) on the antimicrobial (antibiotics and biocides) susceptibilities of food-associated bacterial strains. Methods and Results Adaptive responses of bacterial strains were investigated by exposing the strains daily to increasing sub-inhibitory concentrations of DDAC for 7 days. Following adaptation to DDAC, a 3-fold increase in the MIC values for this biocide was observed in 48% of the Escherichia coli and Listeria monocytogenes strains, and 3% of the Salmonella strains. Reduced susceptibility to other biocides was found with the most important increase in MIC for benzalkonium chloride (BC) and a commercial biocide formulation (Galox Horizon) containing DDAC and glutaraldehyde, for all species except Salmonella. Increase in antibiotic MIC values was more pronounced in Escherichia coli in terms of antibiotic numbers and of magnitude (from 4- to 32-fold increase) and, to a lesser extent, in Salmonella strains. Most of these strains had acquired resistance to ampicillin, cefotaxime, ceftazidime, chloramphenicol and ciprofloxacin. Conclusions The effects of exposure to DDAC on biocides and antibiotics susceptibilities depend upon the bacteria species. Significance and Impact of the Study Extensive use of DDAC at sub-inhibitory concentrations may lead to the development of antibiotic-resistant bacteria and may represent a public health issue This article is protected by copyright. All rights reserved.

In South Western Indian ocean (IO), Extended-Spectrum β-Lactamase producing Enterobacteriaceae (ESBL-E) are a main public health issue. In livestock, ESBL-E burden was unknown. The aim of this study was estimating the prevalence of ESBL-E on commercial farms in Reunion, Mayotte and Madagascar and genes involved. Secondly, risk factors of ESBL-E occurrence in broiler, beef cattle and pig farms were explored. In 2016–2017, commercial farms were sampled using boot swabs and samples stored at 4 °C before microbiological analysis for phenotypical ESBL-E and gene characterization. A dichotomous questionnaire was performed. Prevalences observed in all production types and territories were high, except for beef cattle in Reunion, which differed significantly. The most common ESBL gene was blaCTX-M-1. Generalized linear models explaining ESBL-E occurrence varied between livestock production sectors and allowed identifying main protective (e.g., water quality control and detergent use for cleaning) and risk factors (e.g., recent antibiotic use, other farmers visiting the exploitation, pet presence). This study is the first to explore tools for antibiotic resistance management in IO farms. It provides interesting hypothesis to explore about antibiotic use in IO territories and ESBL-E transmission between pig, beef cattle and humans in Madagascar.

International audience; Quaternary ammonium compounds (QACs) are both cationic surfactants and biocidal substances widely used as disinfectants in the food industry. A sensitive and reliable method for the analysis of benzalkonium chlorides (BACs) and dialkyldimethylammonium chlorides (DDACs) has been developed that enables the simultaneous quantitative determination of ten quaternary ammonium residues in dairy products below the provisional maximum residue level (MRL), set at 0.1mgkg(-1). To the best of our knowledge, this method could be the one applicable to milk and to three major processed milk products selected, namely processed or hard pressed cheeses, and whole milk powder. The method comprises solvent extraction using a mixture of acetonitrile and ethyl acetate, without any further clean-up. Analyses were performed by liquid chromatography coupled with electrospray tandem mass spectrometry detection (LC-ESI-MS/MS) operating in positive mode. A C18 analytical column was used for chromatographic separation, with a mobile phase composed of acetonitrile and water both containing 0.3% formic acid; and methanol in the gradient mode. Five deuterated internal standards were added to obtain the most accurate quantification. Extraction recoveries were satisfactory and no matrix effects were observed. The method was validated using the total error approach in accordance with the NF V03-110 standard in order to characterize the trueness, repeatability, intermediate precision and analytical limits within the range of 5-150mugkg(-1) for all matrices. These performance criteria, calculated by e.noval((R)) 3.0 software, were satisfactory and in full accordance with the proposed provisional MRL and with the recommendations in the European Union SANTE/11945/2015 regulatory guidelines. The limit of detection (LOD) was low (

Verse producten zoals groente en fruit worden tijdens het productieproces behandeld om de aantallen schadelijke micro-organismen te verlagen. Hiermee wordt zowel de houdbaarheid van het product verlengd, als het aantal ziekmakende micro-organismen verlaagd. Deze behandelingen zijn vooral effectief om bacteriën onschadelijk te maken, wat de kans verkleind dat consumenten er ziek van worden. Voor virussen is dit effect echter gering als de behandeling wordt uitgevoerd met de doseringen die de voedselindustrie momenteel gebruikt. Hogere doseringen zijn effectiever, maar tasten de voedselkwaliteit en de kleur en structuur van het product te veel aan. Dit blijkt uit een literatuurstudie van het RIVM naar de effectiviteit van desinfectieprocessen in de voedselindustrie op virussen. De studie is in opdracht van de Nederlandse Voedsel en Warenautoriteit (NVWA) uitgevoerd. Een van de mogelijke behandelingen is producten wassen in water waaraan desinfecterende stoffen zijn toegevoegd, zoals chloorverbindingen, waterstofperoxide of ozon. Verder wordt op kleine schaal gewerkt met behandelingen waarmee ook de micro-organismen worden bereikt die dieper in het product verscholen zitten, zoals het product behandelen met UV- of gammastralen of onder hoge druk plaatsen. Ze zijn echter het meest effectief bij doseringen die de voedselkwaliteit en het karakter ervan aantasten. Een veelbelovende oplossing lijkt de combinatie van verschillende behandelingsmethoden (de 'hurdle-technologie'). Op deze manier kan elke methode onder mildere condities of met een lagere intensiteit worden uitgevoerd, waardoor de structuur en kleur van het product wel behouden blijven. Zorgvuldig onderzoek is echter nodig naar welke combinaties het effectiefst zijn om virussen onschadelijk te maken en die tegelijkertijd de kwaliteit van de verse producten behouden.

L’eau est la vie, c’est un élément primordial de notre vie c’est la raison de préserver toute sources d’eau, et essayer d’éliminer toute forme de contamination qui peut l’atteindre. Il existe plusieurs famille bactérienne qui peuvent contaminer l’eau tel que les coliformes et surtout les coliformes fécaux dont E.Coli qui provoque des maladies mortelles. Ce travail consiste à tester un nouveau copolymère comme désinfectant dont son principe actif est l’zone. Il est constitué de deux molécules (la porphyrine et la P (4-VP)) Ce produit est testé sur quatre souches ATCC, dont les résultats affirment qu’il est efficace mais avec des degrés différents ou Staphylococcus aureus ATCC 6538 présente une sensibilité significative. Mots clés : Eau, contamination, copolymère, désinfectant, souches. Abstract: Water is life, it is an essential part of our lives that is the reason to preserve any sources of water, and try to eliminate all forms of contamination that can reach it. There are several bacterial family that can contaminate water such as coliforms and faecal coliforms which especially E.coli that causes fatal diseases. This work is to test a new copolymer as a disinfectant that its active ingredient is the area. It consists of two molecules (the porphyrin and the P (4- VP) ) This product is tested on four strains ATCC, the results say it is effective but with different degrees or Staphylococcus aureus ATCC 6538 shows a significant sensitivity. Keywords: Water, contamination, copolymer, disinfectant, strains تلخیص : الماء ھو الحیاة، ھو جزء أساسي من حیاتنا وھذا ھو سبب الحفاظ على كل مصادره، و محاولة القضاء على جمیع أشكال التلوث التي یمكن أن تصل إلیھ. ھناك العدید من الأسرة البكتیریة التي یمكن أن تستعمر المیاه مثل بكتیریا القولون البرازیة و بكتیریا القولون التي تسبب الأمراض القاتلة . ھذا العمل ھو لاختبار البولیمرات الجدیدة كمطھر و العنصر النشط فیھ ھو ( ( P ( 4 - VP الاوزون . وھو یتألف من جزیئین ( البورفیرین و وتقول النتائج أنھا فعالة ،ATCC یتم اختبار ھذا المنتج على أربع سلالات تظھر حساسیة ATCC ولكن بدرجات مختلفة و المكورات العنقودیة الذھبیة 6538 كبیرة اتجاھھ. الكلمات المفتاحیة: تلوث المیاه ، البولیمرات ، مطھر ، والسلالات . Références

International audience; Biofilms constitute the prevalent way of life for microorganisms in both natural and man-made environments. Biofilm-dwelling cells display greater tolerance to antimicrobial agents than those that are free-living, and the mechanisms by which this occurs have been investigated extensively using single-strain axenic models. However, there is growing evidence that interspecies interactions may profoundly alter the response of the community to such toxic exposure. In this paper, we propose an overview of the studies dealing with multispecies biofilms resistance to biocides, with particular reference to the protection of pathogenic species by resident surface flora when subjected to disinfectants treatments. The mechanisms involved in such protection include interspecies signaling, interference between biocides molecules and public goods in the matrix, or the physiology and genetic plasticity associated with a structural spatial arrangement. After describing these different mechanisms, we will discuss the experimental methods available for their analysis in the context of complex multispecies biofilms.

Despite established prevention strategies such as standardized skin antisepsis with alcohol rubs, the consequences of nosocomial infections continue to take serious social and economic tolls. Recent discoveries concluded that new targets must be considered for the development of modern antiseptic agents and procedures. Studies have shown that a large number of microorganisms are located within and in the immediate vicinity of the hair follicle shaft, suggesting that the hair follicles act as bacterial reservoirs. Recent investigations have demonstrated that hair follicles also play an important role in skin penetration. In particular, nano-sized liposomes were found to be efficient carriers for drug delivery into the hair follicle. Based on these results, this summary provides an overview of subsequent in vitro and in vivo experimental studies assessing the antiseptic effectiveness of nano-sized liposomes with the bound disinfectant polihexanide. The in vitro study examined the follicular penetration of the curcumin-labeled particle- associated polihexanide into porcine ear skin using laser scanning microscopy. The follicular penetration depth was compared to that of the same curcumin- labeled nanoparticles without bound antiseptic. The images acquired in the transmission and the fluorescent modi were superimposed in order to visualize the distribution of the fluorescent dye inside the hair follicles. While quantitative and qualitative results confirmed the efficient penetration of both solutions into the hair follicles, the average penetration depth of the particles with bound polihexanide was significantly higher than that of particles without bound antiseptic. In the in vivo investigation on the volunteers, bacterial growth was monitored after antisepsis over a period of 2.5 h using swabbing of the skin and bacterial counts. The antiseptic potential of the particle-associated polihexanide was compared to that of a conventional aqueous polihexanide solution. Though not statistically significant in this case, results suggested that the use of a particle-bound antiseptic could accomplish a better and longer lasting antisepsis than in non-particular form. An additional review article was published to provide an overview on the subject of targeted delivery of antiseptics to hair follicles and to evaluate their clinical potential. This overview addressed, in particular, the emerging methods of particle-associated disinfectants and tissue-tolerable plasma (TTP)., Die Folgen von nosokomialen Infektionen führen trotz etablierter Präventionsstrategien wie die standardisierte Hautantiseptik mit Alkohollösungen weiterhin zu schwerwiegenden sozialen und wirtschaftlichen Schäden. Neuere Untersuchungen haben gezeigt, dass künftig neue Ziele für die Entwicklung von modernen Desinfektionsmitteln und Verfahren berücksichtigt werden müssen. Forschungsarbeiten haben offenbart, dass sich eine große Anzahl von Mikroorganismen innerhalb und in unmittelbarer Nähe der Haarfollikel Kanäle befinden. Diese Ergebnisse legen nahe, dass die Haarfollikel ein bakterielles Reservoir darstellen. Andere Arbeiten haben gezeigt, dass Haarfollikel eine wichtige Rolle beim Eindringen von Substanzen in die Haut spielen. Nanopartikel, und insbesondere Liposome, haben sich als effiziente Träger für Substanzlieferungen in die Haarfollikel erwiesen. Basierend auf diesen Entdeckungen wurden in der folgenden Publikationsarbeit zwei aufeinander aufbauende experimentelle in vitro und in vivo Studien durchgeführt, um die antiseptische Wirksamkeit von Liposomen mit angeheftetem Antiseptikum zu untersuchen. Ein weiterer Artikel wurde veröffentlicht, um einen Überblick über das Thema der zielgerichteten Desinfektion zu geben und deren klinischen Anwendungsmöglichkeiten zu beurteilen. Dieser befasst sich insbesondere mit zwei neu aufstrebenden Technologien: partikuläre Desinfektionsmittel und Gewebefreundliches Plasma (tissue-tolerable-Plasma, TTP).

No defrontar-se com os problemas relacionados às condições de saúde humana ou animal, mais especificamente as doenças infecciosas, os seres humanos das mais diversas culturas produzem conhecimentos e recursos para debelá-las. Esse reconhecimento tem despertado em investigadores em ciência o interesse pelo desenvolvimento de pesquisas etnográficas, como acontece aqui no estado do Rio Grande do Sul, visando o levantamento de espécies de plantas medicinais utilizadas por diferentes comunidades. A possibilidade de encontrar entre as plantas nativas alguma propriedade antimicrobiana constitui-se um grande desafio principalmente em um momento com relatos de resistência de microrganismos a inúmeros fármacos e desinfetantes convencionais existentes. Nesse sentido objetivando avaliar a ação desinfetante de plantas consideradas medicinais no Rio Grande do Sul assim como de desinfetantes convencionais como fungicidas, foram utilizadas cepa de Candida albicans ATCC e 21 isolados de Candida krusei, nove isolados de Candida rugosa e um isolado de Candia albicans, em mastite bovina. As plantas foram selecionadas por pesquisa bibliográfica cujo teor tivesse relação com estudos etnográficos no Rio Grande do Sul e, na sequência, foram realizados testes de triagem na forma de decocção e extrato hidroetanólico hidratado (EH), obtido de maceração hidroetanólica 70º GL, desalcoolizada e hidratada ao volume inicial, ambas as formas na proporção 5g/100 mL, frente as densidade as populacionais 105, 104 e 103 UFC/mL da cepa padrão, nos tempo de contato de uma e 24 horas. Da etapa de triagem foi selecionada a planta “Macela” Achyrocline saitureioides na forma de EH para teste com os isolados com as mesmas densidades populacionais usadas na triagem e tempos de contato iniciando em 15 minutos até o tempo em que não mais se observava o crescimento de colônias. Os desinfetantes convencionais Iodóforo e Amônia Quaternária (QAC – cloreto de cetil trimetilamônio) nas concentrações de 100%, 50% e 25%, foram confrontados com a cepa padrão e os 31 isolados de campo na densidade populacional de 106UFC/mL, nos tempos de contato de 15, 30 e 60 minutos, baseado na técnica do teste de suspensão na avaliação quantitativa da atividade fungicida e leveduricida de desinfetantes e antissépticos. A forma de decoto não apresentou diminuição logarítmica nas densidades populacionais testadas, nos tempos preconizados e a forma EH demonstrou diminuição logarítmica e tendo a marcela inibido o crescimento da cepa padrão já na primeira hora de contato sendo, por isso, escolhida para os testes com os isolados que apresentaram inativação entre os tempos contato de 30 minutos e 12 horas. Nos desinfetantes convencionais a menor concentração testada, no menor tempo de contato já foi capaz de inativar as células de leveduras, como era esperado. Em relação a atuação de Achyrocline satureioides a mesma apresentou na forma EH 5g/mL ação que nos permite sua utilização no controle da densidade populacional da levedura Candida spp. When faced with problems related to the conditions of human or animal health,, specifically infectious diseases, human beings of diverse cultures produce knowledge and resources to quenching them. This recognition has attracted the interest of researchers to develop ethnographic studies, as it happens here in the state of Rio Grande do Sul, aiming at the survey of medicinal plants used by different communities. The possibility of finding native plants with antimicrobial property constitutes a major challenge especially in a moment with reports of microrganisms resistance to several drugs and conventional disinfectants. In this way, the aim of this study was to evaluate the Disinfectant activity of medicinal plants from Rio Grande do Sul and the fungicidal activity of conventional disinfectants. The Candida strains used was Candida albicans ATCC and Candida spp strains isolated from bovine mastitis cases (21 isolates of Candida krusei, nine isolates of Candida rugosa and one isolate of Candida albicans). The plants were selected by bibliographic research related to ethnographic studies in Rio Grande do Sul. Later, it was performed screening of decoction and hydrated hydroethanolic extract (HE), obtained by maceration hydroethanol 70 º GL, dealcoholized and hydrated to the initial volume, in the proportion 5 g/100 mL, front standard Candida albicans population densities of 105, 104 and 103 CFU.mL-1, in a contact time of 1 h and 24 h. After screening, the selected plant was “Macela” Achyrocline saitureioides. The hydrated hydroethanolic extract of Achyrocline saitureioides was tested front isolates with the same population densities used in screening and the time of contact begin at 15 minutes until the time that does not observe growth of colonies. The disinfectants iodophor (I) and quaternary amonium (QAC - cetyl trimethylammonium chloride), at concentrations 100%, 50% and 25%, were confronted with standard strain and 31 isolates from mastitis cases, population density of the initial inoculum was 106 CFU /mL, for contact times of 15, 30 and 60 minutes. The method used was dilution by the quantitative suspension test for evaluation of fungicidal and yeasticidal activities of Disinfectants and Antiseptics Chemicals. The decoction form does not present logarithimic reduction of tested population densities, at the recommended time and HE demonstrated logarithimic reduction; Marcela inhibited the growth of the standard strain within the first hour of contact and because of that it was chosen to the tests on isolates. Isolates showed inactivation between 30 minutes to 12 hours of contact time. It was observed that the lowest concentrations of the conventional disinfectants, at the lowest time of contact, inactivated all tested yeasts, as it was expected. Regarding the performance of Achyrocline satureioides, the extract (5g/mL) presented action that allows us to use it in the control of population density of the yeast Candida spp.

Aims The objective of this study was to evaluate the bactericidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. Methods and Results The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains were reference strains and strains representative of contaminating bacteria in the food industry. Each synergistic hydrogen peroxide/acid combination found after 5-min contact time at 20°C in distilled water was then tested in conditions simulating four different use conditions. Thirty-two combinations were synergistic in distilled water; twenty-five of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination was synergistic for all six bacterial strains in distilled water and remained synergistic with interfering substances. Six other combinations maintained their synergistic effect in the presence of an organic load but only for one or two bacterial strains. Conclusions Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. Significance and Impact of the Study A rapid screening method was proposed and used to reveal the synergistic potential of disinfectant and/or sanitizer combinations.

Présentation de l'entreprise ...2 I) Introduction ........................3 II) Synthèse bibliographique .4 II) 1.Escherichia coli (E. coli) ........4 II) 2. Les Antibiotiques II) 2. a Généralités ......4 II) 2. b La résistance aux Céphalosporines de 3ème génération (C3G) ........................................5 II) 3. Les biocides II) 3. a Généralités .......6 II) 3. b Caractéristiques des biocides étudiés ........................7 II) 3. c La tolérance aux biocides étudiés ..............................8 II) 4. Relation entre tolérances aux biocides et résistances aux antibiotiques II) 3. a Contexte général ........9 II) 3. b Lien entre résistance aux antibiotiques et tolérance aux biocides étudiés .....................10 III) Matériels et Méthodes ...11 III) 1. Les souches bactériennes ...11 III) 2. Biocides et Antibiotiques ...11 III) 3. Test de sensibilité aux biocides et aux antibiotiques (phase 1) III) 3. a Mesure de la Concentration Minimale Inhibitrice (CMI) des souche aux biocides .....12 III) 3. b Mesure de la CMI des souches aux antibiotiques ..12 III) 4. Adaptation des souches aux biocides (phase 2) .................13 III) 5. Mesure de la Concentration Minimale Bactéricide (CMB) (phase 3) ......................................13 III) 6. Analyses statistiques .........14 IV) Résultats .........................15 IV) 1. Détermination de la sensibilité des souches aux biocides et aux antibiotiques IV) 1. a Choix des souches .15 IV) 1. b Sensibilité des souches aux trois biocides étudiés (BC, Chx et Hex) .........................15 IV) 1. c Sensibilité des souches aux antibiotiques ...............16 IV) 2. Adaptation des souches au chlorure de benzalkonium, à la chlorhexidine et à l'hexamidine IV) 2. a Impact de l'adaptation sur la sensibilité au biocide concerné ....................................17 IV) 2. b Impact de l'adaptation à l'un des trois biocides sur la sensibilité croisée aux autres biocides .....................19 IV) 2. c Impact de l'adaptation au chlorure de benzalkonium sur la sensibilité aux antibiotiques ..............19 IV) 3. Détermination de la concentration minimale bactéricide...22 V) Discussion .........................24 VI) Conclusion et Perspectives ......27 Bibliographie .........................28 Annexes ................................ 31

Bacterial adaptation to quaternary ammonium compounds (QACs) is mainly documented for benzalkonium chloride (BC) and few data are available for other QACs. The aim of this study was to assess the effects of repeated exposure to different quaternary ammonium compounds (QACs) on the susceptibility and/or resistance of bacteria to other QACs and antibiotics. Escherichia coli strains (n=10) were adapted by daily exposure to increasingly sub-inhibitory concentrations of a QAC for 7 days. Three QACs were studied. Following adaptation, we found similar levels of reduction in susceptibility to QACs with a mean 3-fold increase in the minimum inhibitory concentration (MIC) compared to initial MIC values, whatever the QAC used during adaptation. No significant differences in antibiotic susceptibility were observed between the tested QACs. Antibiotic susceptibility was reduced from 3.5- to 7.5-fold for phenicol compounds, β lactams, and quinolones. Increased MIC was associated with a shift in phenotype from susceptible to resistant for phenicol compounds (florfenicol and chloramphenicol) in 90% of E. coli strains. Regardless of the QAC used for adaptation, exposure to gradually increasing concentrations of this type of disinfectant results in reduced susceptibility to QACs and antibiotics as well as cross-resistance to phenicol compounds in E. coli strains. Extensive use of QACs at sub-inhibitory concentrations may lead to the emergence of antibiotic-resistant bacteria and may represent a public health risk.

Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia / Faculdade de Medicina Veterinária While goats are not, in most cases, associated with intensive production, this practice has been increasingly common. With the intensification of production, it has become important to develop a controlled environment to optimize resources and reduce costs. The objectives of this study were to monitor and control the quality of air inside a room of artificial milk feeding for kids and come up with improvements to it. We also aimed to analyze droppings from goat kids to assess the usefulness of applying a commercial disinfectant to reduce the emission of ammonia. We studied the temperature, humidity and concentrations of carbon dioxide and ammonia, and analyzed the concentrations of ammonium and Kjeldahl nitrogen of manure, and its pH and electrical conductivity. The values of temperature, relative humidity, carbon dioxide and ammonia were within those recommended. The pH was higher in samples with disinfectant and electrical conductivity was higher in samples without disinfectant. Samples with disinfectant had lower losses of ammonium and electrical conductivity, leading to believe that this could be useful to reduce the emission of ammonia.

Campylobacter is responsible for human bacterial enteritis and poultry meat is recognised as a primary source of infection. In slaughterhouses, cleaning and disinfection procedures are performed daily, and it has been suggested that disinfectant molecules might select for antibiotic resistant strains if shared targets or combined resistance mechanisms were involved. The aim of the study was to investigate if cleaning and disinfection procedures in poultry slaughterhouses select for antibiotic resistance in Campylobacter jejuni and C. coli and to determine the genotypes of isolates collected after cleaning and disinfection. Nine sampling visits were made to four French slaughterhouses. Samples were collected from transport crates and equipment surfaces, before and after cleaning and disinfection. Minimal inhibitory concentrations of the recovered C. jejuni and C. coli isolates to six antibiotics and two disinfectants were measured. The C. jejuni isolates collected from equipment surfaces after cleaning and disinfection were subjected to PCR-RFLP typing. Twenty-five C. jejuni isolates and 1 C. coli were recovered from equipment surfaces after cleaning and disinfection during five visits to three different slaughterhouses. Those isolates did not show an increased resistance to the tested antibiotics compared to isolates collected before cleaning and disinfection. Only one or two genotypes were recovered after cleaning and disinfection during single visits to each slaughterhouse. This observation suggests that such genotypes may be particularly adapted to survive cleaning and disinfection stress. Understanding the survival mechanisms of Campylobacter should facilitate the implementation of better-targeted strategies and reduce the public health burden associated with Campylobacter infection.

Årsliste 2006 NIVA har gjennomført på oppdrag for VADE as en rekke tester med desinfeksjonsmiddelet VADEvann i løpet av våren og forsommeren 2006. Hensikten har vært å undersøke VADEvanns egnethet som desinfeksjonsmiddel i badeanlegg. VADEvann viste seg å være et effektivt desinfeksjonsmiddel mot bakterier som er betraktet som problemorganismer i badeanlegg. Med den mest robuste av testorganismene, indikatororganismen Pseudomonas aeruginosa, ble det oppnådd en 4-log10-inaktivering med en VADEvanndose på 0,2 mg fritt Cl2/l ved en kontakttid på 1 min. Dette var ca halvparten av nødvendig dose med HOCl (tilsatt som hypokloritt og målt som fritt klor) for å oppnå samme inaktiveringsgrad av Ps. aerugionsa. Det er mulig det vil kunne være vanskelig å overholde et eventuelt krav til bundet klor tilsvarende det som gjelder ved bruk av hypokloritt dersom vannets innhold av nitrogen og organisk stoff er høyt. VADE AS, Hexum, AS

La contamination des cultures in vitro est beaucoup plus élevée en climat tropical qu'en zone tempérée. Pour la micropropagation, l'emploi d'antibiotiques dans le milieu de culture n'est pas suffisant. Il faut prélever l'explant dans la partie extrême de la tige puis appliquer plusieurs désinfectants comme le Desogerme, l'alcool ou l'eau de javel