1. Investigación

Listeriosis is a zoonotic disease caused by Listeria monocytogenes and Listeria ivanovii. The genus Listeria currently includes 27 recognized species and is found throughout the environment. The number of systematic studies on antimicrobial resistance in L. monocytogenes isolates from domestic farms using antimicrobial substances is limited. Importantly, dairy ruminant farms are reservoir of hypervirulent lineage I L. monocytogenes isolates, previously associated with human clinical cases. Considering that the classes of antibiotics used in food-producing domestic animals are frequently the same or closely related to those used in human medicine, studies about the impact of antibiotic use on the acquisition of antibiotic resistance in Listeria spp. in domestic animal farms are, therefore, of high importance. Here, susceptibility to 25 antibiotics was determined. Eighty-one animal-related, 35 food and 21 human pathogenic Listeria spp. isolates and 114 animal-related non-pathogenic Listeria spp. isolates were tested. Whole genome sequencing data was used for molecular characterization. Regarding L. monocytogenes, 2 strains from the clinical-associated linage I showed resistance to erythromycin, both related to dairy ruminants. Acquired resistance to one antibiotic was exhibited in 1.5% of L. monocytogenes isolates compared with 14% of non-pathogenic Listeria spp. isolates. Resistance to tetracycline (7.9%), doxycycline (7.9%), penicillin (4.4%), and ampicillin (4.4%) were the most frequently observed in non-pathogenic Listeria spp. While resistance to two or more antibiotics (5.6%) was most common in Listeria spp., isolates, resistance to one antibiotic was also observed (1.6%). The present results show that non-pathogenic Listeria spp. harbour antimicrobial resistance genes.

Introduction: The complexity of fighting contagious agalactia (CA) has raised the necessity of alternative antimicrobial therapies, such as probiotics. Lactic acid bacteria (LAB) are present in the mammary gland of small ruminants and their antimicrobial effect have been previously described against species like Mycoplasma bovis but never against Mycoplasma agalactiae (Ma). This in vitro study aims to evaluate the antimicrobial activity against Ma of ovine and caprine LAB strains and a human commercial probiotic (L2) of Lactobacillus spp. Methods: A total of 63 possible LAB strains were isolated from nine ovine and caprine farms in Spain, three isolates (33B, 248D, and 120B) from the 63 strains were selected, based on their capacity to grow in a specific medium in vitro, for an in vitro experiment to assess their antimicrobial activity against Ma in Ultra High Temperature (UHT) processed goat milk (GM). A women commercial vaginal probiotic was also included in the study. The inoculum of L2 was prepared at a concentration of 3.24 × 108 CFU/mL and the average concentration of the inoculum of the wild LAB varied from 7.9 × 107 to 8.4 × 108 CFU/mL. Results: The commercial probiotic L2 significantly reduced the concentration of Ma to 0.000 log CFU/mL (p < 0.001), strain 33B reduced it from 7.185 to 1.279 log CFU/mL (p < 0.001), and 120B from 6.825 to 6.466 log CFU/mL (p < 0.05). Strain 248D presented a bacteriostatic effect in GM. Moreover, the three wild strains and the commercial probiotic produced a significative reduction of the pH (p < 0.001). Discussion: This is the first in vivo report of the antimicrobial potential of LAB strains against Ma and its interaction. Our results support possible future alternative strategies to antibiotic therapy, previously not contemplated, to fight CA in small ruminants. Further studies are necessary to elucidate the action mechanisms through which these LAB are able to inhibit Ma and to assess the safety of using these strains in possible in vivo studies.

Para llevar a cabo el diagnóstico de gestación en el ganado bovino, se debe utilizar un método preciso, seguro, económico y que se pueda realizar de manera temprana. Aunque varias técnicas están actualmente disponibles en el mercado, otras siguen todavía en desarrollo, siendo posibles herramientas diagnósticas a tener en cuenta en un futuro. Por ello, el presente trabajo tiene como objetivo hacer una revisión sobre las diversas técnicas de diagnóstico de gestación (DG) y su potencial uso a nivel comercial, tanto en el presente como en el futuro, de la ganadería bovina. Los métodos directos para el DG, como son la palpación directa o la ecografía del tracto reproductor vía transrectal, siguen siendo los más empleados en la actualidad durante el control gestacional en el ganado vacuno. Son técnicas diagnósticas con buenos resultados y son interesantes a nivel económico, pero son herramientas invasivas y requieren una cierta experiencia por parte del técnico que las realiza. En general, se aplican a partir de la 3ª-4ª semana posterior a la inseminación artificial. Por otro lado, los métodos indirectos de DG son menos invasivos que los directos. Mediante este tipo de diagnósticos vía indirecta se puede detectar la presencia o ausencia de un embrión, sin visualizar directamente estructuras gestacionales. Existen métodos indirectos basados en signos clínicos, como la vigilancia del retorno al estro, así como técnicas indirectas bioquímicas, que permiten evaluar mediante el uso de kits rápidos ciertas sustancias como la progesterona (P4) o las Glicoproteínas Asociadas a la Gestación (GPAG), producidas durante la gestación de forma temprana. Otras técnicas novedosas y prometedoras, pero que todavía se encuentran en desarrollo, son la evaluación de moléculas como el interferón tau (IFNτ), los micro-ARN (miARN) y/o los Factores de Gestación Temprana (FGT).

Background: Salmonellosis is one of the most important food-borne zoonotic disease affecting both animals and humans. The objective of the present study was to identify gastrointestinal (GI) lactic acid bacteria (LAB) of canineorigin from Salmonella-negative dogs’ faeces able to inhibit monophasic Salmonella Typhimurium previously isolated from dogs’ faeces, in order to be used as a potential probiotic in pet nutrition. Results: Accordingly, 37 LAB were isolated from Salmonella-negative dogs’ faeces and tested against monophasic S. Typhimurium using the spot on lawn method out of which 7 strains showed an inhibition halo higher than 2.5 cm. These 7 strains were also tested with the co-culture method and one showed the greatest inhibition value (p < 0.05). Subsequently, the isolate was identified through 16S rRNA sequencing and sequence homology and designated as Ligilactobacillus salivarius (L. salivarius). LAB from Salmonella-positive dogs were also identified and none was the selected strain. Finally, to identify the mechanism of inhibition of L. salivarius, the supernatant was analyzed, and a dose response effect was observed. Conclusions: It is concluded that the canine-origin L. salivarius, could possess some in vitro functional attributes of a candidate probiotic and could prevent monophasic S. Typhimurium colonization or inhibit its activity if the infection occurs.

La importancia de la producción de cordero en el Sureste, la existencia de un núcleo de trashumantes de ovino en la Sierra de Segura, y la consideración de la trashumancia como manifestación representativa del patrimonio cultural inmaterial nos ha llevado a explorar el potencial docente de la trashumancia con ovino segureño para estudiantes de veterinaria. Entre 2016 y 2019, cuatro profesores y dieciocho estudiantes de veterinaria de las Universidades de Murcia y Cardenal Herrera (UCH-CEU) de Valencia, hemos realizado diecinueve jornadas de trashumancia. Entre las acciones de innovación docente generadas destaca la exposición fotográfica “La Vereda de los Pontoneros” y el documental “Trashumancia, la Última Frontera”. Proponemos la integración de una semana de trashumancia en el periodo de las dos semanas de prácticas tuteladas con la Asociación Nacional de Criadores de Ovino Segureño (ANCOS), discutimos su integración en el grado de Veterinaria de Murcia y evidenciamos el interés docente de esta actividad inmersiva, que supera los propios contenidos del grado de veterinaria.

La pandemia Covid-19 ha motivado la adopción de medidas excepcionales en todo el mundo, a efectos de limitar los contagios y el colapso de los sistemas sanitarios. El cierre de comercios y otras actividades consideradas no esenciales, o las limitaciones al movimiento, ha generado un impacto económico en el sector de los pequeños rumiantes, poniendo de manifiesto la necesidad del profesional veterinario de disponer de las competencias necesarias para valorar económicamente el impacto de las enfermedades en los colectivos. Este trabajo analiza, en primer lugar, la formación en economía que reciben los estudiantes del Grado de Veterinaria en las diferentes facultades españolas, comparándola con la que reciben los estudiantes en el Grado de Ingeniería Agrícola. En segundo lugar, se ha diseñado una encuesta para egresados y estudiantes de último curso de veterinaria, en referencia a este tipo de competencias, su aplicación en la sanidad animal y su repercusión en el desempeño profesional. Los datos evidencian que el tiempo empleado para adquirir las competencias en economía de los veterinarios es menor (3-6 créditos en 5 años) que el que disponen los ingenieros agrícolas (12 créditos en 4 años). Los resultados de la encuesta revelan que, si bien se registran diferencias significativas cuantitativamente entre egresados y estudiantes, ambos grupos coinciden en la escasa formación recibida para valorar el impacto de las enfermedades en los colectivos, así como en la necesidad de formarse en aspectos de gestión económica una vez finalizados sus estudios de grado para el desempeño de su labor profesional, competencias que deberían ser reforzadas en el grado. Entre los egresados, la opinión es similar, independientemente de los años de desempeño profesional.

Bovine respiratory disease (BRD) is an important viral and/or bacterial disease that mainly affects feedlot calves. The involvement of Mycoplasma bovis in BRD can lead to chronic pneumonia poorly responsive to antimicrobial treatment. Caseonecrotic bronchopneumonia is a pulmonary lesion typically associated with M. bovis. In Spain, M. bovis is widely distributed in the feedlots and circulating isolates are resistant to most antimicrobials in vitro. However, the role of this species in clinical respiratory disease of feedlot calves remains unknown. Furthermore, available data are relative to a fixed panel of antimicrobials commonly used to treat BRD, but not to the specific set of antimicrobials that have been used for treating each animal. This study examined 23 feedlot calves raised in southeast Spain (2016–2019) with clinical signs of respiratory disease unresponsive to treatment. The presence of M. bovis was investigated through bacteriology (culture and subsequent PCR), histopathology and immunohistochemistry. The pathogen was found in 86.9% (20/23) of the calves, mainly in the lungs (78.26%; 18/23). Immunohistochemistry revealed M. bovis antigens in 73.9% (17/23) of the calves in which caseonecrotic bronchopneumonia was the most frequent lesion (16/17). Minimum inhibitory concentration assays confirmed the resistance of a selection of 12 isolates to most of the antimicrobials specifically used for treating the animals in vivo. These results stress the importance of M. bovis in the BRD affecting feedlot calves in Spain.

Studies 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 largescale 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. Listeria 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. Sixtyone 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. Listeria 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 faecal shedding. This study highlights dairy farms as a reservoir for hypervirulent L. monocytogenes.

Las aves acuáticas silvestres representan el principal reservorio natural de los virus influenza y han participado en el reordenamiento tanto de virus pandémicos como de los virus responsables de los brotes de gripe aviar en las especies domésticas y silvestres. Con el objetivo de conocer los determinantes implicados, en el presente trabajo se revisaron los casos humanos de influenza aviar asociados al manejo de aves silvestres y la utilización de los equipos de protección personal, así como las bases de la vigilancia de la influencia aviar altamente patógena en aves silvestres en España. Las evidencias existentes permiten concluir que la transmisión directa de virus influenza desde las aves silvestres al ser humano es un evento raro. No obstante, nuestro contexto epidemiológico se encuentra influido por el cambio climático y queda marcado por la presencia de rutas migratorias desde territorios donde la infección puede estar presente. Por ello, y ante las implicaciones clínicas, económicas y para la salud pública que dichas infecciones pueden tener, los diferentes colectivos expuestos a las aves silvestres (veterinarios, biólogos, ornitólogos, conservacionistas, técnicos de campo, agentes medioambientales, cetreros, cazadores, etc.) deberían conocer las posibles fuentes de contagio y manejar correctamente los equipos de protección personal. Al mismo tiempo, es importante que dichos grupos conozcan la situación sanitaria actualizada respecto a la influenza aviar, para adaptar sus actividades en consecuencia y poder aplicar las medidas de protección de forma proporcionada a la misma, amén de aportar una valiosa información para los programas de vigilancia. / Wild waterfowl are considered the main natural reservoir of influenza viruses and they have contributed to the reassortment of both pandemic viruses and viruses responsible for outbreaks of avian influenza in wild and domestic species. In order to determinate the factors involved, we reviewed the human cases of avian influenza related to the management of wild birds, the use of personal protective equipment, as well as the basis of surveillance programs of highly pathogenic avian influenza in wild birds in Spain. The direct transmission of influenza virus from wild birds to humans is a rare event. However, our epidemiological context is influenced by climate change and marked by the presence of migratory routes from territories where infection may be present. Thus, and due to the clinical, economical and public health implications that such infections may have, the different groups exposed to wild birds (veterinarians, biologists, ornithologists, conservationists, field technicians, environmental officers, falconers, hunters, etc.) should know which are the possible sources of infection and how to handle the personal protective equipment. Besides, it is important that those groups know the current sanitary situation regarding avian influenza so they can consequently adapt their activities and employ proper protective measures, in addition to providing valuable information for surveillance programs.