Proyecto de Investigación en Microbiología Médica

Nivel educativo: Grado Duración (en horas): Más de 50 horasLa asignatura Proyecto de Investigación se imparte en tercer curso del Grado de Medicina de la Facultad de Medicina y Odontología de la UPV/EHU, y tiene una duración de 6 ECTS. El objetivo principal de la asignatura es adquirir habilidades básicas para el diseño y desarrollo de un proyecto de investigación sobre temas de biomédica básica y aplicada, y concretamente sobre Microbiología Médica, así como para la comunicación científica de los resultados obtenidos. Se pretende que los estudiantes identifiquen los pasos fundamentales del proceso de investigación partiendo de una idea viable. El desarrollo de la asignatura llevará consigo a que el alumnado conozca las convocatorias a las que solicitar financiación, sea capaz de elaborar una memoria de investigación para una convocatoria concreta, desarrolle y ejecute un diseño experimental y, finalmente, analice y elabore los resultados para presentarlos en el congreso de estudiantes que tiene lugar al final del curso. La existencia del congreso introduce el reto y la motivación para que el alumnado se implique en el trabajo que conlleva el presentar en dicho evento un proyecto innovador y exitoso

Candidiasis by Candida glabrata, Candida nivariensis and Candida bracarensis in Galleria mellonella: Virulence and Therapeutic Responses to Echinocandins

Candida albicans is the major etiological agent of invasive candidiasis but the increasing prevalence of emerging species of Candida, such as Candida glabrata and phylogenetically closely related species, Candida nivariensis and Candida bracarensis, requires special attention. Differences in virulence among these species and their therapeutic responses using in vivo non-mammalian models are scarcely analysed. The aim of this study was analyse the survival of G. mellonella and host-pathogen interactions during infection by C. glabrata, C. nivariensis and C. bracarensis. Moreover, therapeutic responses to echinocandins were also assessed in the G. mellonella model of candidiasis. These three species produced lethal infection in G. mellonella; C. glabrata was the most virulent species and C. bracarensis the less. Haemocytes of G. mellonella phagocytised C. bracarensis cells more effectively than those of the other two species. Treatment with caspofungin and micafungin was most effective to protect larvae during C. glabrata and C. nivariensis infections while anidulafungin was during C. bracarensis infection. The model of candidiasis in G. mellonella is simple and appropriate to assess the virulence and therapeutic response of these emerging Candida species. Moreover, it successfully allows for detecting differences in the immune system of the host depending on the virulence of pathogens.This research was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO) [SAF2017-86188-P and PID2020-117983RB-I00] and from the Consejería de Educación, Universidades e Investigación of Gobierno Vasco-Eusko Jaurlaritza [GIC15/78 IT-990-16]. Ainara Hernando-Ortiz was funded by Ph.D. grants from the University of the Basque Country (PIF 16/39)

Antimicrobial Peptides with Anti-Candida Activity

[EN] Mycoses are accountable for millions of infections yearly worldwide. Invasive candidiasis is the most usual, presenting a high morbidity and mortality. Candida albicans remains the prevalent etiologic agent, but the incidence of other species such as Candida parapsilosis, Candida glabrata and Candida auris keeps increasing. These pathogens frequently show a reduced susceptibility to commonly used antifungal drugs, including polyenes, triazoles and echinocandins, and the incidence of emerging multi-drug-resistant strains of these species continues to increase. Therefore, the need to search for new molecules that target these pathogenic species in a different manner is now more urgent than ever. Nature is an almost endless source of interesting new molecules that could meet this need. Among these molecules, antimicrobial peptides, present in different sources in nature, possess some advantages over conventional antifungal agents, even with their own drawbacks, and are considered as a promising pharmacological option against a wide range of microbial infections. In this review, we describe 20 antimicrobial peptides from different origins that possess an activity against Candida.This research was funded by the Spanish Ministry of Science and Innovation (PID2020-117983RB-I00) and by the Consejería de Educación, Universidades e Investigación of Gobierno Vasco-Eusko Jaurlaritza (IT1607-22). A.P.-R. was funded by a Ph.D. grant from the University of the Basque Country (PIF17/167)

In vitro activities of carvacrol, cinnamaldehyde and thymol against Candida biofilms

[EN]Oral candidiasis is frequently associated with Candida biofilms. Biofilms are microbial communities related to persistent, recalcitrant and difficult to-treat infections. Conventional treatments are not sufficient to overcome biofilm-associated candidiasis; thus, the search of new antifungal compounds is necessary. In the current study, we have evaluated the effect of three phytocompounds, carvacrol, cinnamaldehyde and thymol, against Candida planktonic and sessile cells. Reduction in biofilm biomass and metabolic activity was assessed during adhesion and mature biofilm phases. Candida albicans was the most biofilm-producing Candida species. All phytocompounds tested were fungicidal against Candida planktonic cells. Cinnamaldehyde was the most active in inhibiting biofilm adhesion, but carvacrol and thymol significantly reduced both mature biofilm biomass and metabolic activity. These results highlight the role of cinnamaldehyde, carvacrol and thymol as promising alternatives for the treatment of candidiasis due to their antibiofilm capacities, and stress the necessity to continue studies on their safety, toxicity and pharmacodynamics and pharmacokinetics.This work was supported by Gobierno Vasco-Eusko Jaurlaritza, Spain [grant number GIC15/78 IT-990-16, 2016] and Fundacion ONCE "Oportunidad al Talento", Spain and Fondo Social Europeo, Spain [CMA, 2018]

Virulence of Candida Auris from Different Clinical Origins in Caenorhabditis Elegans and Galleria Mellonella Host Models

Candida auris is an emerging multidrug-resistant fungal pathogen responsible for nosocomial outbreaks of invasive candidiasis. Although several studies on the pathogenicity of this species have been reported, the knowledge on C. auris virulence is still limited. This study aims to analyze the pathogenicity of C. auris, using one aggregating isolate and eleven non-aggregating isolates from different clinical origins (blood, urine and oropharyngeal specimens) in two alternative host models of candidiasis: Caenorhabditis elegans and Galleria mellonella. Furthermore, possible associations between virulence, aggregation, biofilm-forming capacity, and clinical origin were assessed. The aggregating phenotype isolate was less virulent in both in vivo invertebrate infection models than non-aggregating isolates but showed higher capacity to form biofilms. Blood isolates were significantly more virulent than those isolated from urine and respiratory specimens in the G. mellonella model of candidiasis. We conclude that both models of candidiasis present pros and cons but prove useful to evaluate the virulence of C. auris in vivo. Both models also evidence the heterogeneity in virulence that this species can develop, which may be influenced by the aggregative phenotype and clinical origin.This work was supported by the Euskal Herriko Unibertsitatea [PIF 16/39]; Euskal Herriko Unibertsitatea [PIF17/167]; Eusko Jaurlaritza [GIC15/78 IT-990-16]; Ministerio de Economia y Competitividad [SAF2017-86188-P]

In vitro and in vivo anti-Candida activity of citral in combination with fluconazole

[EN] Background The ability of Candida to develop biofilms on inert surfaces or living tissues favors recalcitrant and chronic candidiasis associated, in many instances, with resistance to current antifungal therapy. Aim The aim of this study was to evaluate the antifungal activity of citral, a phytocompound present in lemongrass essential oil, in monotherapy and combined with fluconazole against azole-resistant Candida planktonic cells and biofilms. The effect of citral combined with fluconazole was also analysed with regard to the expression of fluconazole resistance-associated genes in Candida albicans and the effectiveness of the combination therapy in a Caenorhabditis elegans model of candidiasis. Results Citral reduced biofilm formation at initial stages and the metabolic activity of the mature biofilm. The combination of citral with fluconazole was synergistic, with a significant increase in the survival of C. elegans infected with Candida. RNA analysis revealed a reduction of the expression of the efflux pump encoded by MDR1, leading to a greater effect of fluconazole. Conclusion Citral in monotherapy and in combination with fluconazole could represent an interesting therapy to treat recalcitrant Candida infections associated to biofilms.This research was supported by Gobierno Vasco-Eusko Jaurlaritza [Eusko Jaurlaritza GIC15/78 IT-990-16] and by Fundacion ONCE "Oportunidad al Talento" and Fondo Social Europeo CM-A [C.M.-A.]; Ministerio de Economia, Industria y Competitividad, Gobierno de Espan [PID2020-117983RB-I00]

Proyecto de Investigación en Microbiología Médica

Nivel educativo: Grado Duración (en horas): Más de 50 horasLa asignatura Proyecto de Investigación se imparte en tercer curso del Grado de Medicina de la Facultad de Medicina y Odontología de la UPV/EHU, y tiene una duración de 6 ECTS. El objetivo principal de la asignatura es adquirir habilidades básicas para el diseño y desarrollo de un proyecto de investigación sobre temas de biomédica básica y aplicada, y concretamente sobre Microbiología Médica, así como para la comunicación científica de los resultados obtenidos. Se pretende que los estudiantes identifiquen los pasos fundamentales del proceso de investigación partiendo de una idea viable. El desarrollo de la asignatura llevará consigo a que el alumnado conozca las convocatorias a las que solicitar financiación, sea capaz de elaborar una memoria de investigación para una convocatoria concreta, desarrolle y ejecute un diseño experimental y, finalmente, analice y elabore los resultados para presentarlos en el congreso de estudiantes que tiene lugar al final del curso. La existencia del congreso introduce el reto y la motivación para que el alumnado se implique en el trabajo que conlleva el presentar en dicho evento un proyecto innovador y exitoso

Microexplant cultures of the cerebellum

Background: We report on the functional screening and identification of an active quorum quenching (QQ) gene in the Komagataeibacter europaeus strain CECT 8546, which is a member of the acetic acid bacteria (AAB). Results: Using a previously published screening protocol (Schipper et al., in Appl Environ Microbiol 75: 224-233, 2009. doi: 10.1128/AEM.01389-08) for QQ genes, we identified a single gene, designated gqqA, that interfered strongly with bacterial quorum sensing (QS) in various reporter strains. It encodes for a 281-amino acid protein with a molecular mass of 30 kDa. Although the GqqA protein is similar to predicted prephenate dehydratases, it does not complement Escherichia coli mutants of the pheA gene, thus indicating a potentially different function. Recombinant GqqA protein attenuated QS-dependent pyocyanin production and swarming motility in the Pseudomonas aeruginosa strain PAO1. Moreover, GqqA quenched the QS response of the Agrobacterium tumefaciens NTL4 and the Chromobacterium violaceum CV026 reporter strains. Interestingly, the addition of recombinant GqqA protein to growing cultures of the Komagataeibacter europaeus strain CECT 8546 altered the cellulose production phenotype of CECT 8546 and other AAB strains. In the presence of GqqA protein, cells were planktonic, and no visible cellulose biofilms formed. The addition of low levels of N-acylhomoserine lactones maintained the biofilm formation phenotype. Conclusions: Our data provide evidence for an interconnection between QS and AAB cellulose biofilm formation as well as QQ activity of the GqqA protein.This work was supported by BMBF within the ChemBiofilm Network at the University of Hamburg and by the Grant GL2010-22152-C03-02 from the Spanish Ministry of Science and Innovation. Collaboration between the two groups was possible through the fellowship AP2009-0843 from the Spanish Ministry of Education, Culture and Sports for M.J. Valera

"Abordaje multidisciplinar y difusión social de un problema sanitario"

La Universidad, como institución académica de enseñanza superior e investigación, debe ser capaz de formar profesionales competentes en diferentes ámbitos de aplicación, preparados para afrontar problemas complejos que requieran un abordaje multidisciplinar. Así mismo, el conocimiento adquirido durante la fase de formación universitaria debe transmitirse de una forma clara y comprensible a la sociedad. En este sentido, las redes sociales pueden representar una interesante herramienta de divulgación para mejorar la comunicación y el acercamiento entre la universidad y la sociedad. Este trabajo planteó un escenario complejo dentro del ámbito sanitario, como es el aumento en la aparición de resistencias a los antibióticos, para que los equipos multidisciplinares formados por alumnado de distintos grados lo trabajasen desarrollando las competencias transversales y específicas de cada grado, estableciendo de esta manera sinergias de colaboración. Posteriormente, se desarrolló un blog en el aula, donde los diferentes equipos de trabajo multidisciplinar reflejaban sus soluciones a los escenarios planteados, utilizando un lenguaje divulgativo para acercar su conocimiento a la sociedad preocupada por el uso adecuado de los antibióticos. De esta manera, mediante la utilización de metodologías activas, el alumnado tomó conciencia de la importancia del trabajo multidisciplinar, así como de la difusión del conocimiento adquirido