Antimicrobianos naturales de origen marino frente a Helicobacter pylori

[ES] Helicobacter pylori es una bacteria altamente prevalente en humanos (60-80 %), primera causa de inflamación crónica estomacal, asociada en los casos graves con cáncer gástrico, siendo la única bacteria carcinogénica reconocida hasta la fecha. El agua contaminada y diversos alimentos han sido relacionados con la supervivencia y diseminación de H. pylori en el ambiente y su transmisión al hombre a través de la cadena alimentaria. La efectividad de la única terapia antibiótica de aplicación para erradicar la infección por este patógeno ha decaído drásticamente, debido a que cada vez se detectan más cepas resistentes. Ante la necesidad de buscar sustancias naturales antimicrobianas como alternativas efectivas, los compuestos de origen marino se presentan como un nicho sostenible de recursos con gran potencial nutricional y bioactivo. Los compuestos de origen marino constituyen en nuestros días una fuente inagotable y sostenible de recursos con elevada aplicabilidad en la industria farmacéutica, alimentaria y estética. Las algas pardas del género Phaeophyceae son especialmente ricas en carbohidratos complejos de elevado potencial bioactivo. Entre ellos, el compuesto FUCOIDAN, polisacárido sulfatado de algas pardas, favorece el crecimiento de la microbiota intestinal beneficiosa; estimula el sistema inmune; inhibe la replicación viral; posee efecto antioxidante, anti-inflamatorio y anticancerígeno, siendo denominado el “nutriente del futuro”. En el contexto expuesto, y como respuesta a la urgente necesidad de investigar sobre antimicrobianos alternativos a los antibióticos, altamente efectivos frente Helicobacter pylori, patógeno emergente de reconocida relevancia en salud pública, el objetivo principal del presente estudio es: Evaluar el potencial antimicrobiano in vitro del compuesto FUCOIDAN obtenido de diversas especies de algas pertenecientes al género Phaeophyceae, algas pardas de elevada riqueza en dicho polisacárido bioactivo, frente a H. pylori. Los resultados obtenidos del estudio evidencian la existencia de capacidad antimicrobiana del compuesto natural FUCOIDAN frente a H. pylori y sugieren que el uso de antimicrobianos naturales de origen marino podría complementar, o incluso ser una alternativa, al uso de antibióticos frente a H. pylori, especialmente cuando aparecen resistencias.[EN] Helicobacter pylori is a highly prevalent bacteria in humans (60-80 %), first cause of chronical stomach inflammation associated with severe cases of gastric cancer, being the only carcinogenic bacterium recognized to date. Contaminated water and different foods, have been highlighted for their role in the survival and dissemination of H. pylori in the environment and its transmission to humans throughout the food chain. The effectiveness of the unique antibiotic therapy of application to eradicate the infection by this pathogen has declined drastically, mainly due to the development of resistances. Due to the need of looking for natural antimicrobial substances, as an effective alternative, marine compounds are presented as a sustainable niche of resources with great nutritional and bioactive potential. Marine origin compounds constitute in our days an inexhaustible and sustainable source of resources with a high applicability in the pharmacological, food and aesthetic industry. Brown algae from the Phaeophyceae genre are primarily rich in complex carbohydrates with high bioactive potential. Between them, the complex FUCOIDAN, sulphated polysaccharide of brown algae which encourages the growth of the beneficial intestinal microbiota; stimulates the immune system; inhibits the viral replication; has an antioxidant, anti-inflammatory and anticancer effects, being named as the “nutrient of the future”. In the exposed context, and as an answer to the urgent need to investigate about highly effective alternative antimicrobials to the antibiotics against Helicobacter pylori, an emergent pathogen recognised as relevant in public health, the main objective of this study is: To evaluate the antimicrobial potential in vitro of the compound FUCOIDAN obtained from different algae species belonging to the Phaeophyceae genre, brown algae of high richness in this bioactive polysaccharide, against H. pylori. The results obtained from this study show the existence of antimicrobial capacity of the natural compound FUCOIDAN against H. pylori and suggest that the use of natural antimicrobials of marine origin could be a complementary, or even alternative, therapy against H. pylori, especially when resistances are detected.[CA] Helicobacter pylori, és un bacteri altament prevalent en humans (60- 80 %), primera causa d'inflamació crònica estomacal, i en els casos greus càncer gàstric, sent l'únic bacteri carcinogen reconegut fins a l’actualitat. L'aigua contaminada, i diversos aliments, han sigut destacats pel seu paper en la supervivència i disseminació de H. pylori en l'ambient, i la seua transmissió a l'home a través de la cadena alimentària. L'efectivitat de l'única teràpia antibiòtica d'aplicació per a eradicar la infecció per este patogen ha decaigut dràsticament. Davant de la necessitat de buscar substàncies naturals antimicrobianes, com a alternatives efectives, els compostos d'origen marí es presenten com un nínxol sostenible de recursos amb gran potencial nutricional i bioactiu. Els compostos d'origen marí constitueixen en els nostres dies una font inesgotable i sostenible de recursos amb elevada aplicabilitat en la indústria farmacèutica, alimentària i estètica. Les algues terroses del gènere Phaeophyceae són especialment riques en carbohidrats complexos d'elevat potencial bioactiu. Entre ells, el compost FUCOIDAN, polisacàrid sulfatat d'algues terroses, afavoreix el creixement de la microbiota intestinal beneficiosa; estimula el sistema immune; inhibeix la replicació viral; posseeix efecte antioxidant, antiinflamatori i anticancerigen, sent denominat el "nutrient del futur". En el context exposat, i com a resposta a la urgent necessitat d'investigar sobre antimicrobians alternatius als antibiòtics, altament efectius front Helicobacter pylori, patogen emergent de reconeguda rellevància en salut pública, l'objectiu principal del present estudi és: Avaluar el potencial antimicrobià in vitro del compost FUCOIDAN obtingut de diverses espècies d'algues pertanyents al gènere Phaeophyceae, algues terroses d'elevada riquesa en dit polisacàrid bioactiu, enfront de H. pylori. Els resultats obtinguts de l'estudi evidencien l'existència d'una capacitat antimicrobiana front a H. pylori a causa del compost natural FUCOIDAN y suggerixen que l'ús d'antimicrobians naturals d'origen marí podria complementar, o inclús ser una alternativa, a l'ús d'antibiòtics enfront de H. pylori, especialment quan apareixen resistències.Palacios Gorba, C. (2018). Antimicrobianos naturales de origen marino frente a Helicobacter pylori. http://hdl.handle.net/10251/107020TFG

Pathogenicity and virulence of Listeria monocytogenes: A trip from environmental to medical microbiology

Listeria monocytogenes is a saprophytic gram-positive bacterium, and an opportunistic foodborne pathogen that can produce listeriosis in humans and animals. It has evolved an exceptional ability to adapt to stress conditions encountered in different environments, resulting in a ubiquitous distribution. Because some food preservation methods and disinfection protocols in foodprocessing environments cannot efficiently prevent contaminations, L. monocytogenes constitutes a threat to human health and a challenge to food safety. In the host, Listeria colonizes the gastrointestinal tract, crosses the intestinal barrier, and disseminates through the blood to target organs. In immunocompromised individuals, the elderly, and pregnant women, the pathogen can cross the blood-brain and placental barriers, leading to neurolisteriosis and materno-fetal listeriosis. Molecular and cell biology studies of infection have proven L. monocytogenes to be a versatile pathogen that deploys unique strategies to invade different cell types, survive and move inside the eukaryotic host cell, and spread from cell to cell. Here, we present the multifaceted Listeria life cycle from a comprehensive perspective. We discuss genetic features of pathogenic Listeria species, analyze factors involved in food contamination, and review bacterial strategies to tolerate stresses encountered both during food processing and along the host’s gastrointestinal tract. Then we dissect host–pathogen interactions underlying listerial pathogenesis in mammals from a cell biology and systemic point of view. Finally, we summarize the epidemiology, pathophysiology, and clinical features of listeriosis in humans and animals. This work aims to gather information from different fields crucial for a comprehensive understanding of the pathogenesis of L. monocytogenes

Caenorhabditis elegans as an in vivo model to assess fucoidan bioactivity preventing Helicobacter pylori infection

Currently, Helicobacter pylori is the unique biological carcinogenic agent. The search for antimicrobial alternatives to antibiotics against this pathogen has been categorized as a priority due to the drastic failure associated with current applied antibiotic therapy. The present study assessed the bioactive antimicrobial capability of fucoidan (“Generally Recognized as Safe” approval – European Commission December 2017) from different species of Phaeophyceae algae (Fucus vesiculosus, Undaria pinnatifida, Macrocystis pyrifera) against H. pylori. All the studied fucoidans showed bacteriostatic and bactericidal effects at the studied concentrations [5–100] μg ml−1 and exposure times [0–7 days]. The most effective anti-H. pylori fucoidan was validated in Caenorhabditis elegans as an in vivo model. C. elegans feed was supplemented with Undaria pinnatifida [0–100] μg ml−1 fucoidan, resulting in a significant improvement in lifespan, lowered H. pylori concentration in the digestive tract, and increased egg-laying pattern. New research lines proposing this compound as an active agent in nutraceutical and preventive novel therapies should be opened.The present research work has been supported by the funds provided by the Spanish Ministry of Economy and Competitiveness (MINECO) under both projects with reference AGL2014-53875-R and AGL2017-86840-C2-2-R. M. C. Pina-Pérez is also grateful to the EC providing a H2020 MSCA – IF Grant Agreement No. 748314.Peer reviewe

Listeria spp. Isolated from Tonsils of Wild Deer and Boars: Genomic Characterization

International audienceListeria monocytogenes is a major human and animal foodborne pathogen. However, data from environmental reservoirs remain scarce. Here, we used whole-genome sequencing to characterize Listeria species isolates recovered over 1 year from wild animals in their natural habitats in Spain. Three different Listeria spp. (L. monocytogenes [n = 19], Listeria ivanovii subsp. londoniensis [n = 4], and Listeria innocua [n = 3]) were detected in 23 animal tonsils (9 deer, 14 wild boars) and 2 feeding troughs. No Listeria species was detected in feces. L. monocytogenes was detected in tonsils of 44.4% (8 out of 18) of deer and 40.7% (11 out of 27) of wild boars. L. monocytogenes isolates belonged to 3 different core genome multilocus sequence typing (cgMLST) types (CTs) of 3 distinct sublineages (SL1, SL387, and SL155) from lineages I and II. While cgMLST type L1-SL1-ST1-CT5279 (IVb; clonal complex 1 [CC1]) occurred only in one animal, types L1-SL387-ST388-CT5239 (IVb; CC388) and L2-SL155-ST155-CT1170 (IIa; CC155) were retrieved from multiple animals. In addition, L1-SL387-ST388-CT5239 (IVb; CC388) isolates were collected 1 year apart, revealing their long-term occurrence within the animal population and/or environmental reservoir. The presence of identical L. monocytogenes strains in deer and wild boars suggests contamination from a common food or environmental source, although interhost transmission cannot be excluded. Pathogenicity islands LIPI-1, LIPI-3, and LIPI-4 were present in 100%, 5%, and 79% of the L. monocytogenes isolates, respectively, and all L. monocytogenes lineage II isolates (n = 3) carried SSI-1 stress islands. This study highlights the need for monitoring L. monocytogenes environmental contamination and the importance of tonsils as a possible L. monocytogenes intrahost reservoir

Pathogenicity and virulence of Listeria monocytogenes: A trip from environmental to medical microbiology

Listeria monocytogenes is a saprophytic gram-positive bacterium, and an opportunistic foodborne pathogen that can produce listeriosis in humans and animals. It has evolved an exceptional ability to adapt to stress conditions encountered in different environments, resulting in a ubiquitous distribution. Because some food preservation methods and disinfection protocols in food-processing environments cannot efficiently prevent contaminations, L. monocytogenes constitutes a threat to human health and a challenge to food safety. In the host, Listeria colonizes the gastrointestinal tract, crosses the intestinal barrier, and disseminates through the blood to target organs. In immunocompromised individuals, the elderly, and pregnant women, the pathogen can cross the blood-brain and placental barriers, leading to neurolisteriosis and materno-fetal listeriosis. Molecular and cell biology studies of infection have proven L. monocytogenes to be a versatile pathogen that deploys unique strategies to invade different cell types, survive and move inside the eukaryotic host cell, and spread from cell to cell. Here, we present the multifaceted Listeria life cycle from a comprehensive perspective. We discuss genetic features of pathogenic Listeria species, analyze factors involved in food contamination, and review bacterial strategies to tolerate stresses encountered both during food processing and along the host’s gastrointestinal tract. Then we dissect host–pathogen interactions underlying listerial pathogenesis in mammals from a cell biology and systemic point of view. Finally, we summarize the epidemiology, pathophysiology, and clinical features of listeriosis in humans and animals. This work aims to gather information from different fields crucial for a comprehensive understanding of the pathogenesis of L. monocytogenes.Spanish Ministry of Science and Innovation (PGC2018-096364-B-I00). JJQ was supported by the Generalitat Valenciana (GV/2018/A/183) and the Spanish Ministry of Science and Innovation (PID2019-110764RA-I00 /AEI/10.13039/501100011033). FG-dP was supported by the European Union’s Horizon 2020 Research-and-Innovation Program under Marie Sklodowska-Curie grant agreement no. 721456. JJQ was a recipient of the “Ramón y Cajal” Programme from the Spanish Ministry of Science, Innovation, and Universities (RYC-2018-024985-I). AM-G was funded by the Youth Employment Initiative from the Comunidad de Madrid. CP-G was funded by the Universidad Cardenal Herrera-CE

Genomic characterization of Listeria spp. isolated from tonsils, udder and feces of domestic dairy ruminants in Spain

International audienceTwo species of Listeria are pathogenic, Listeria monocytogenes and Listeria ivanovii. Although studies have shown that dairy ruminants shed Listeria spp. in feces, there is little information about ruminants that do not shed Listeria spp. in their feces but asymptomatically carry them in organs. We evidence that ruminants can asymptomatically carry L. ivanovii in udders and L. monocytogenes and L. ivanovii in tonsils without fecal shedding. Whole-genome sequence of L. monocytogenes and L. ivanovii contained known core genes involved in virulence and antibiotic resistance. This work highlights tonsils and udders as a Listeria intra-host site of colonization

Ruminant‐associated Listeria monocytogenes isolates belong preferentially to dairy‐associated hypervirulent clones: a longitudinal study in 19 farms

International audienceStudies have shown that ruminants constitute reservoirs of Listeria monocytogenes, but little is known about the epidemiology and genetic diversity of this pathogen within farms. Here we conducted a large-scale longitudinal study to monitor Listeria spp. in 19 dairy farms during three consecutive seasons (N=3251 samples). L. innocua was the most prevalent species, followed by L. monocytogenes. L. monocytogenes was detected in 52.6% of farms and more frequently in cattle (4.1%) and sheep (4.5%) than in goat farms (0.2%). Lineage I accounted for 69% of L. monocytogenes isolates. Among animal samples, the most prevalent sublineages (SL) and clonal complexes (CC) were SL1/CC1, SL219/CC4, SL26/CC26 and SL87/CC87, whereas SL666/CC666 was most prevalent in environmental samples. 61 different L. monocytogenes cgMLST types were found, 28% common to different animals and/or surfaces within the same farm and 21% previously reported elsewhere in the context of food and human surveillance. L. monocytogenes prevalence was not affected by farm hygiene but by season: higher prevalence was observed during winter in cattle, and during winter and spring in sheep farms. Cows in their second lactation had a higher probability of L. monocytogenes fecal shedding. This study highlights dairy farms as a reservoir for hypervirulent L. monocytogenes