Person: Álvarez Sánchez, Julio
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First Name
Julio
Last Name
Álvarez Sánchez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Veterinaria
Department
Sanidad Animal
Area
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Item Evaluation of a new enzyme-linked immunosorbent assay for the diagnosis of tuberculosis in goat milk(Research in Veterinary Science, 2020) Roy, A.; Infantes-Lorenzo, J.A.; Dominguez, M.; Moreno, I.; Pérez Sancho, Marta; García Benzaquén, Nerea; García-Seco Romero, María Teresa; Álvarez Sánchez, Julio; Romero Martínez, Beatriz; Gortázar, C.; Juan Ferré, Lucía De; Domínguez Rodríguez, Lucas José; Bezos Garrido, JavierCaprine tuberculosis (TB) is a zoonosis with sanitary and economic repercussions. Caprine TB control programs are based on a test and cull strategy using the intradermal tuberculin tests and slaughterhouse surveillance. However, this approach is not always feasible and may have a limited sensitivity under specific circumstances. In this study, performance of a new experimental test based on the P22 protein complex (P22 ELISA) was evaluated in two TB-infected herds using milk and serum samples and compared with cell-based diagnostic tests. Samples from a low (n = 62, herd 1) and a high (n = 52, herd 2) TB prevalence herd were selected. Moreover, bulk tank milk samples from both herds were analysed using the P22 ELISA. At the end of the study, a group of animals (n = 21) was euthanized and subjected to post-mortem analysis and bacteriological culture. Significant differences (p < .001) on the qualitative and quantitative (ODs) results were observed between herds using both serum and milk samples in the P22 ELISA. The correlation observed in the quantitative results obtained in serum and milk samples was very strong in animals from flock 2 (rs = 0.91) and moderate in animals from flock 1 (rs = 0.46). Among the slaughtered animals, the P22 ELISA detected a higher proportion of lesion-culture positive animals than cell-based diagnostic tests (61.9 and 66.7% using milk and serum samples, respectively). The P22 ELISA using milk samples demonstrated a similar sensitivity compared with serum samples, suggesting it might be a valuable test for TB control in dairy goats.Item MicroMundo: una aproximación a la perspectiva One Health de Salud Global mediante Aprendizaje-Servicio integrando diversos niveles educativos(2022) González Zorn, Bruno; Román González, Elvira; Molina Martín, María; Martín Brieva, Humberto; Escudero García-Calderón, José Antonio; Rodríguez Fernández, Carmina; Bezos Garrido, Javier; Álvarez Sánchez, Julio; Pérez Sancho, Marta; Amaro Torres, Francisco; Jiménez Cid, Víctor; Suárez Rodríguez, Mónica; Patiño Álvarez, Aurora Belén; Calvo De Pablo, Pilar; Fernández-Acero Bascones, Teresa; Pavón Verges, Mónica; Sanz Santamaría, Ana Belén; Díaz Del Toro, Silvia; González Rubio, Gema; Vázquez Estévez, María Covadonga Inmaculada; Gil Serna, Jessica; Jiménez Gutiérrez, Elena; Del Val Oriza, Elba; Valentí Sanguino, Marta; Sellers Moya, Ángela; Sastre Vergara, LucíaMicroMundo es la adaptación a Aprendizaje-Servicio (ApS) de la estrategia de crowdsourcing y ciencia ciudadana internacional Tiny Earth. Su objetivo de servicio esencial es acercar la cultura científica, la perspectiva One Health y la investigación biomédica a la sociedad, poniendo el foco en jóvenes estudiantes para fomentar la vocación por formación en Grados STEM y por la investigación. La pandemia de COVID-19 y sus consecuencias han puesto de manifiesto la urgencia de acercar la cultura científica en el ámbito de la Biomedicina y la Salud Pública a la sociedad e implicar en esta tarea a nuestros estudiantes. Pero también la pandemia ha impuesto cambios en nuestro esquema de trabajo durante este curso, lo que nos ha obligado a trabajar on-line en lugar de llevar a cabo las características actividades experimentales de aprendizaje activo en las que se fundamenta el proyecto en condiciones normales. Manteniendo los mismos objetivos, las intervenciones en los 20 Colegios e Institutos en los que hemos realizado el proyecto se han enfocado en la elaboración de materiales divulgativos e intervenciones en la comunidad por parte de los jóvenes estudiantes, de manera coordinada por nuestros estudiantes universitarios y la organización de un Simposio on-line de ámbito nacional donde se expusieron y compartieron las diversas iniciativas. La elevada participación en el Simposio, de inscripción gratuita (más de 500 inscritos) y la calidad de las 69 ponencias propuestas, la mayoría de manera conjunta por alumnos de instituto y universitarios, avala el enorme éxito de la iniciativa virtual y la consecución de objetivos. El material generado (videojuegos, entornos educativos virtuales, paisajes de aprendizaje, escape rooms, videos, campañas en Instagram o Tik Tok, blogs, etc) será muy valioso como material de apoyo en sucesivas ediciones de MicroMundo. Todo este material se irá divulgando en el portal www.esmisionposible.com las redes sociales @EsMisionPosible, gestionados por el proyecto. En resumen, consideramos que nuestro proyecto que implica tanto a estudiantes y profesores de centros educativos de Educación Secundaria y Bachillerato en la CAM a, como a profesores y estudiantes universitarios de los ámbitos de Sanidad Humana, Animal y Medioambiental de manera transversal e interfacultativa, ha afrontado con éxito el reto de adaptar el proyecto a la situación epidemiológica, reforzándolo con actividades no presenciales orientadas a consolidar una comunidad MicroMundo virtual en la que los estudiantes pueden compartir sus experiencias en la divulgación del problema de la resistencia y el fomento de la investigación para el descubrimiento de nuevos antimicrobianos.Item Comparison of four different culture media for isolation and growth of type II and type I/III Mycobacterium avium subsp. paratuberculosis strains isolated from cattle and goats(Applied and Environmental Microbiology, 2006) Juan Ferré, Lucía De; Álvarez Sánchez, Julio; Romero Martínez, Beatriz; Bezos Garrido, Javier; Castellanos, Elena; Aranaz Martín, Alicia; Mateos García, Ana Isabel; Domínguez Rodríguez, Lucas JoséCulture is considered the definitive technique for Johne's disease diagnosis, and it is essential for later applications of certain molecular typing techniques. In this study, we have tested four solid media (Herrold's egg yolk medium [HEYM] with sodium pyruvate and mycobactin [HEYMm-SP], HEYM with mycobactin and without sodium pyruvate [HEYMm], Middlebrook 7H11 with mycobactin [Mm], and Löwenstein-Jensen with mycobactin [LJm]) for isolation of Mycobacterium avium subsp. paratuberculosis strains in 319 tissue samples from cattle herds and goat flocks. We have shown that each of the two main groups of M. avium subsp. paratuberculosis (type II and type I/III) has different requirements for growth in the culture media studied. The recommended solid media for isolation of type I/III strains are LJm and Mm, since the combination of both media allowed the recovery of all these strains. The most widespread culture medium, HEYM, is not suitable for the isolation of this group of M. avium subsp. paratuberculosis strains. Regarding the type II strains, HEYMm-SP was the medium where more strains were isolated, but the other three media are also needed in order to recover all type II strains. The incubation period is also related to the strain type. In conclusion, because the type of strain cannot be known in advance of culture, coupled with the fact that cattle and goats can be infected with both groups of strains, we recommend the use of the four solid media and the prolongation of the incubation period to more than 6 months to detect paratuberculous herds/flocks and to determine the true prevalence of the infection.Item Occurrence of Mycobacterium avium subspecies paratuberculosis across host species and European countries with evidence for transmission between wildlife and domestic ruminants(BMC microbiology, 2009) Stevenson, Karen; Álvarez Sánchez, Julio; Bakker, Douwe; Biet, Franck; Juan Ferré, Lucía De; Denham, Susan; Dimareli, Zoi; Dohmann, Karen; Gerlach, Gerald F; Heron, Ian; Kopecna, Marketa; May, Linda; Pavlik, Ivo; Sharp, J Michael; Thibault, Virginie C; Willemsen, Peter; Zadoks, Ruth N; Greig, AlastairBACKGROUND Mycobacterium avium subspecies paratuberculosis (Map) causes an infectious chronic enteritis (paratuberculosis or Johne's disease) principally of ruminants. The epidemiology of Map is poorly understood, particularly with respect to the role of wildlife reservoirs and the controversial issue of zoonotic potential (Crohn's disease). Genotypic discrimination of Map isolates is pivotal to descriptive epidemiology and resolving these issues. This study was undertaken to determine the genetic diversity of Map, enhance our understanding of the host range and distribution and assess the potential for interspecies transmission. RESULTS 164 Map isolates from seven European countries representing 19 different host species were genotyped by standardized IS900--restriction fragment length polymorphism (IS900-RFLP), pulsed-field gel electrophoresis (PFGE), amplified fragment length polymorphisms (AFLP) and mycobacterial interspersed repeat unit-variable number tandem repeat (MIRU-VNTR) analyses. Six PstI and 17 BstEII IS900-RFLP, 31 multiplex [SnaBI-SpeI] PFGE profiles and 23 MIRU-VNTR profiles were detected. AFLP gave insufficient discrimination of isolates for meaningful genetic analysis. Point estimates for Simpson's index of diversity calculated for the individual typing techniques were in the range of 0.636 to 0.664 but a combination of all three methods increased the discriminating power to 0.879, sufficient for investigating transmission dynamics. Two predominant strain types were detected across Europe with all three typing techniques. Evidence for interspecies transmission between wildlife and domestic ruminants on the same property was demonstrated in four cases, between wildlife species on the same property in two cases and between different species of domestic livestock on one property. CONCLUSION The results of this study showed that it is necessary to use multiple genotyping techniques targeting different sources of genetic variation to obtain the level of discrimination necessary to investigate transmission dynamics and trace the source of Map infections. Furthermore, the combination of genotyping techniques may depend on the geographical location of the population to be tested. Identical genotypes were obtained from Map isolated from different host species co-habiting on the same property strongly suggesting that interspecies transmission occurs. Interspecies transmission of Map between wildlife species and domestic livestock on the same property provides further evidence to support a role for wildlife reservoirs of infection.Item Analysis of the cattle movement network and its association with the risk of bovine tuberculosis at the farm level in Castilla y Leon, Spain(Transboundary and Emerging Diseases, 2019) Pozo Piñol, Pilar; Bezos Garrido, Javier; Álvarez Sánchez, Julio; VanderWaal, Kimberly; Grau, Anna; de la Cruz Conty, María Luisa; Nácar, Jesus; Pérez, Andrés; Mínguez, OlgaBetween-farm transmission of bovine tuberculosis (bTB) occurs mostly through fence-to-fence contact between neighbouring farms, endemic infected wildlife or movement of infected animals. Unfortunately, bTB detection is frequently delayed and identification of the source of introduction is often difficult, particularly in endemic regions. Here, we characterized the cattle movement network of Castilla y Leon, a high bTB-prevalence (1.9% at the farm level in 2015) region in Spain, over six years and analysed the distribution of bTB to ultimately assess the likelihood of spatial and movement-mediated transmission. We analysed movement and bTB data from 27,633 units located in the region, of which 87% were involved in ~1.4 million movements of ~8.8 million animals. Network-level connectivity was low, although a few highly connected units were identified. Up to 15% of the herds became bTB-positive at some point during the study, with the highest percentage found in bullfighting and beef herds. Although bTB-positive herds had a significantly higher degree and moved more cattle than negative herds. Results of the k-test, a permutation-based procedure, suggested that positive farms were not significantly clustered in the movement network. Location was a likely risk factor as bTB-positive farms tended to be located within 5 km from each other. Results suggested that movements may be a source of bTB in cattle in Castilla y Leon, although local factors may be more influential in determining risk of disease at the farm level. The description of the movement network in Castilla y Leon may be valuable for bTB surveillance in Spain. Moreover, results are useful to assess the movement-associated risk for multiple diseases.Item Management of an outbreak of brucellosis due to B. melitensis in dairy cattle in Spain(Research in Veterinary Science, 2011) Álvarez Sánchez, Julio; Sáez, Jose Luis; García Benzaquén, Nerea; Serrat, Carles; Pérez Sancho, Marta; González Domínguez, Sergio; Ortega, Maria Jesús; Gou, Josep; Carbajo, Lucio; Garrido, Fulgencio; Goyache Goñi, Joaquín; Domínguez Rodríguez, Lucas JoséBrucella melitensis is a major human and animal pathogen, with a wide host range that includes all domestic ruminant species, although small ruminants are its preferred hosts. Outbreaks in cattle due to B. melitensis have become a worldwide emerging problem particularly difficult to control due to the lack of knowledge on the epidemiology in this host species and of an effective vaccine. However, combination of molecular tools and strict biosecurity measures can help to solve these difficulties and eventually eradicate the disease from infected herds. In the present report, management of an outbreak in Spain involving four farms, more than 2000 cattle and several human cases is described. Application of Multiple Locus VNTR Analysis (MLVA) allowed identifying the most likely source of infection. Stamping out and test-and-slaughter strategies were applied, proving their usefulness to control the outbreak depending on infection level, and without the need of other alternative measures.Item Assessment of the sensitivity of the bovine tuberculosis eradication program in a high prevalence region of Spain using scenario tree modeling(Preventive Veterinary Medicine, 2019) De la Cruz, María Luisa; Pozo Piñol, Pilar; Grau, Anna; Nacar, Jesús; Bezos Garrido, Javier; Pérez, Andrés; Domínguez Rodríguez, Lucas José; Sáez, José Luís; Mínguez-González, Olga; Juan Ferré, Lucía De; Álvarez Sánchez, JulioIn spite of the efforts invested to eradicate bovine tuberculosis (bTB) in cattle, the disease is still present in several developed countries, including Spain. Among the factors related with disease persistence in high prevalence areas, the lack of sensitivity of the screening test for detection of infected herds [single intradermal tuberculin (SIT) test] can play a major role. Here, a scenario tree model mimicking the diagnostic test scheme in place in the region of Castilla y Leon (Spain) was developed to estimate the probability of detecting bTB in an infected-non detected officially tuberculosis free (OTF) herd (herd sensitivity, HSe). In order to do so the probability of detecting at least one positive animal in the SIT test with/without post-mortem (detection of lesions and culture) confirmation in an infected herd was estimated using Monte Carlo simulation through @ RISK (Palisade Co, NY, USA). Uncertainty on the accuracy of the diagnostic tests was introduced in the model using distributions based on the literature. The performance of the model was evaluated by comparing the predicted number of SIT/post-mortem positive animals in infected herds with those observed in newly detected bTB-infected herds in the region in 2011–2015. The estimated HSe of the SIT test was 76.2% (95% probability interval: 19.8–97.6). According to the model, bTB infection would be then confirmed through culture in 65.3% (95% PI: 50.0–82.3) of the herds detected through the SIT test, so that overall the proportion of infected-non detected OTF herds in which the infection could be confirmed after the initial SIT test was 49.6% (95% PI: 9.75–80.3). The predicted HSe of both SIT test and culture was directly correlated with herd size. Results from the model suggest a moderate but highly variable HSe of the current surveillance system in place for bTB detection in OTF herds located in high prevalence areas, that could be maximized by performing multiple tests within a year as indicated in the Spanish eradication program (with a median SIT HSe of 87% when two consecutive tests were considered). In addition, these results highlight the usefulness of performing subsequent SIT tests to rule out infection in SIT-positive herds even when the causative agent cannot be isolated.Item MicroMundo: Ciencia Ciudadana para el descubrimiento y concienciación sobre el uso de antibióticos mediante Aprendizaje-Servicio(2020) Jiménez Cid, Víctor; Calvo De Pablo, Pilar; Román González, Elvira; Patiño Álvarez, Aurora Belén; González Zorn, Bruno; Gómez-Luz Centellés, María Luisa; Molina Martín, María; Martín Brieva, Humberto; Escudero García-Calderón, José Antonio; Pavón Verges, Mónica; Rodríguez Fernández, Carmina; Díaz Del Toro, Silvia; Rodríguez Escudero, María Isabel; Vázquez Estévez, María Covadonga Inmaculada; Bezos Garrido, Javier; Álvarez Sánchez, Julio; Amaro Torres, Francisco; Suárez Rodríguez, Mónica; Gil Serna, Jessica; Fernández-Acero Bascones, Teresa; Sanz Santamaría, Ana Belén; González Rubio, Gema; Jiménez Gutiérrez, Elena; Coronas Serna, Julia María; Valentí Sanguino, Marta; Del Val Oriza, Elba; Sellers Moya, Ángela; Gibello Prieto, Alicia; Arias López, Patricia; Sastre Vergara, LucíaMicroMundo es un proyecto de Ciencia Ciudadana basado en aprendizaje activo, en el que estudiantes de ESO y Bachillerato, objeto del servicio, coordinados por equipos de estudiantes universitarios, objeto del aprendizaje, desarrollan un proyecto de investigación real. El objetivo de la investigación es el aislamiento, a partir de microorganismos de muestras de suelo, de nuevas actividades antibióticas. Los objetivos de servicio son acercar cultura científica a la sociedad en Salud Global, con foco en el problema de la resistencia a antibióticos, actuando sobre la población más joven,al tiempo que se crean en ellos vocaciones STEM y curiosidad por la I+D en Biomedicina. Durante el curso 2019-20, 150 nuevos alumnos se han incorporado al proyecto interfacultativo en la UCM, trabajando en 26 centros educativos de la Comunidad de Madrid. El confinamiento por la situación pandémica ha reforzado el interés del proyecto, pero ha obligado a pasar el entorno on-line algunas de las actuaciones previstas. No obstante, los objetivos del proyecto se han alcanzado.Item Nature of the low-temperature 3 x 3 surface phase of Pb/Ge(111)(Physical review letters, 1999) Mascaraque Susunaga, Arantzazu; Avila, A.; Asensio, M. C.; Ferrer, S.; Michel, E. G; Álvarez Sánchez, JulioThe structure of the low-temperature 3 X 3 surface phase of Pb/Ge(111) has been determined by surface x-ray diffraction experiments. Analysis of the data reveals that the Pb layer exhibits a vertical corrugation of similar to 0.4 Angstrom, affecting also the two top Ge layers. Significant distortions are found down to the third Ge layer. This structural model supports that the 3 X 3 ground state can be best described as a cooperative distortion stabilized by a gain in electronic energy. [S0031-9007(99)08749-9].Item Phenotypic and genetic characterization of antimicrobial resistance in Salmonella enterica serovar Choleraesuis isolates from humans and animals in Spain from 2006 to 2021(Journal of Antimicrobial Chemotherapy, 2024) Camille Jacqueline; Clara Samper-Cativiela; Sara Monzon Fernandez; Ugarte Ruiz, María; Isabel Cuesta de la Plaza; Álvarez Sánchez, Julio; Silvia Herrera-LeonObjectics: While an increase in the levels of MDR in Salmonella enterica sevorar Choleraesuis has been reported in Europe, little is known about the situation in Spain. Therefore, we first aimed to assess the phenotypic resistance profile and to determine the presence of genetic determinants of resistance of S. Choleraesuis isolates collected in animal and human. Our second objective was to identify and characterize clusters of highly related isolates. Methods: We analysed 50 human and 45 animal isolates retrieved from 2006 to 2021 using the disc diffusion method and performed WGS followed by analyses of genetic determinants and phylogenetic analysis. Results: All isolates were of ST145 and corresponded to the variant Kunzendorf. Swine isolates harboured a significantly higher number of antimicrobial resistance genes than human isolates, and often carried plasmid replicons of the IncHI2/IncHI2A type (42% of all animal isolates). In addition, we identified several MDR S. Choleraesuis strains circulating in humans and swine between 2006 and 2021. The phylogenetic analyses identified four clades associated with specific patterns of resistance genes and plasmid replicons. The clades also included isolates that differed in terms of year and region of isolation as well as host of origin. Conclusions: This One Health approach highlights that reducing human MDR S. Choleraesuis infections may require the adoption of strategies that not only seek to prevent cases in humans but also to characterize and reduce the infection burden in swine.