Gene expression profiling in human neutrophils after infection with Acinetobacter baumannii in vitro

Acinetobacter baumannii is a Gram negative nosocomial pathogen that has acquired increasing worldwide notoriety due to its high antibiotic resistance range and mortality rates in hospitalized patients. Therefore, it is necessary to better understand key aspects of A. baumannii pathogenesis such as host-pathogen interactions. In this report, we analyzed both gene expression and cytokine production by human neutrophils infected with A. baumannii. Our assays reveal a proinflammatory response of neutrophils after A. baumannii infection, since intracellular transcription of effector proteins such as COX-2, transcription factors, and proinflammatory cytokines resulted significantly upregulated in neutrophils infected by A. baumannii, compared with unstimulated human neutrophils. Translation and release of CXCL-8, IL-1? and TNF-? by neutrophils was confirmed by protein quantification in culture supernatants. Results obtained in this report reinforce the importance of human neutrophils in controlling A. baumannii infections but also emphasize the proinflammatory nature of these host-pathogen interactions as a target for future immunomodulatory therapies

Antimicrobial Susceptibility and Characterization of Resistance Mechanisms of Corynebacterium urealyticum Clinical Isolates

Corynebacterium urealyticum is a non-diphtherial urease-producing clinically relevant corynebacterial, most frequently involved in urinary tract infections. Most of the C. urealyticum clinical isolates are frequently resistant to several antibiotics. We investigated the susceptibility of 40 C. urealyticum isolated in our institution during the period 2005-2017 to eight compounds representative of the main clinically relevant classes of antimicrobial agents. Antimicrobial susceptibility was determined by the Epsilometer test. Resistance genes were searched by PCR. All strains were susceptible to vancomycin whereas linezolid and rifampicin also showed good activity (MICs90 = 1 and 0.4 mg/L, respectively). Almost all isolates (39/40, 97.5%) were multidrug resistant. The highest resistance rate was observed for ampicillin (100%), followed by erythromycin (95%) and levofloxacin (95%). Ampicillin resistance was associated with the presence of the blaA gene, encoding a class A ?-lactamase. The two rifampicin-resistant strains showed point mutations driving amino acid replacements in conserved residues of RNA polymerase subunit ? (RpoB). Tetracycline resistance was due to an efflux-mediated mechanism. Thirty-nine PFGE patterns were identified among the 40 C. urealyticum, indicating that they were not clonally related, but producing sporadic infections. These findings raise the need of maintaining surveillance strategies among this multidrug resistant pathogen.This research was funded by Plan Nacional de I+D+i 2013-2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades, Spanish Network for Research in Infectious Diseases (REIPI) D16/0016/0007 and RD16/0016/0008), and co-financed by European Development Regional Fund “A way to achieve Europe”, Operative program Intelligent Growth 2014-2020

POTENCIAL PROBIÓTICO DE CEPAS DE BACILLUS CON PROPIEDADES ANTIMICROBIANAS FRENTE A PATÓGENOS DE PECES

El objetivo de este trabajo ha sido aislar, identificar y caracterizar cepas bacterianas procedentes de ambiente marino, fitoplancton, zooplancton, huevos, larvas de lenguado y diferentes juveniles (branquias, intestino, piel), que pudieran tener actividad probiótica y actividad antibacteriana frente a distintos patógenos de peces. Se aislaron un total de 217 cepas bacterianas. Tras un primer cribado mediante ensayos de inhibición en placa frente a patógenos, se seleccionaron 9 cepas y se identificaron utilizando la secuenciación de su rRNA 16S. Los resultados mostraron que las mejores candidatas eran cepas del género Bacillus. Varios de estas posibles cepas candidatas se caracterizaron in vitro para determinar su potencial probiótico, mediante ensayos de inhibición en co-cultivo con V. anguillarum, resistencia a bilis de pez, y adherencia a mucus intestinal de pez. Nuestros resultados mostraron que algunas de las cepas seleccionadas pertenecientes al género Bacillus, podrían ser consideradas como potenciales probióticos frente a patógenos de peces, por lo que el beneficio de la administración de estas cepas a cultivos de peces será posteriormente estudiada

Actividad bacteriocinogénica de bacterias aisladas de digestivos de peces marinos salvajes

El crecimiento exponencial que ha sufrido la acuicultura en las últimas décadas ha dado lugar a un incremento en número y virulencia de las enfermedades bacterianas que afectan a los peces cultivados. Hasta la fecha, el control de estas enfermedades se ha realizado a través del uso de vacunas y antibióticos, así como de la desinfección del agua y el control biológico, el uso de inmunoestimulantes no-específicos y suplementos dietéticos, entre otros. Pero una mala gestión de estas enfermedades, asociada sobre todo al abuso de antibióticos, ha sido asociada a la aparición de reservorios de bacterias resistentes a antibióticos, tanto en animales como en el ambiente acuático, con el consiguiente peligro para la salud humana (1, 2). El empleo de bacteriocinas como alternativa a los antibióticos parece ser una alternativa plausible para el control y tratamiento de estas enfermedades de una manera inocua y sostenible (3, 4). Pese a que en los últimos años se ha intensificado la búsqueda de cepas productoras de bacteriocinas frente a bacterias patógenas marinas, desafortunadamente todavía son pocas las cepas totalmente caracterizadas (5). El presente estudio tiene por objetivo caracterizar cepas bacterianas con actividad bacteriocinogénica aisladas de intestinos de peces salvajes del Mar Cantábrico. Para ello se procesaron un total de 19 intestinos pertenecientes a 19 ejemplares, cada uno de una especie diferente capturados en el Mar Cantábrico (Cantabria). De estas muestras se aislaron un total de 198 colonias en medio de cultivo TSA, en base a su morfología, color y brillo, que fueron seleccionadas para comprobar su actividad antagonista frente a patógenos de peces de acuicultura. Como cepas indicadoras patógenas de peces se emplearon: Vibrio splendidus y Vibrio anguillarum, y cepas patógenas aisladas de cultivos de lenguado senegalés (Solea senegalensis). Se detectaron 15 cepas de bacterias marinas que presentaban actividad antagonista frente al menos una de las cepas patógenas, de las cuales 4 mostraron actividad inhibitoria frente a más de una especie patógena. La identificación de las cepas procedentes del medio marino seleccionadas se realizó mediante la secuenciación del gen 16S ARN, presentando una homología >99% a Myroides sp. y Alcaligenes sp. Finalmente se estudió el efecto de los parámetros físico-químicos en la actividad bactericida (pH, temperatura y proteasas)

Human neutrophils phagocytose and kill Acinetobacter baumanii and A. pittii

Acinetobacter baumannii is a common cause of health care associated infections worldwide. A. pittii is an opportunistic pathogen also frequently isolated from Acinetobacter infections other than those from A. baumannii. Knowledge of Acinetobacter virulence factors and their role in pathogenesis is scarce. Also, there are no detailed published reports on the interactions between A. pittii and human phagocytic cells. Using confocal laser and scanning electron microscopy, immunofluorescence, and live-cell imaging, our study shows that immediately after bacteria-cell contact, neutrophils rapidly and continuously engulf and kill bacteria during at least 4 hours of infection in vitro. After 3 h of infection, neutrophils start to release neutrophil extracellular traps (NETs) against Acinetobacter. DNA in NETs colocalizes well with human histone H3 and with the specific neutrophil elastase. We have observed that human neutrophils use large filopodia as cellular tentacles to sense local environment but also to detect and retain bacteria during phagocytosis. Furthermore, co-cultivation of neutrophils with human differentiated macrophages before infections shows that human neutrophils, but not macrophages, are key immune cells to control Acinetobacter. Although macrophages were largely activated by both bacterial species, they lack the phagocytic activity demonstrated by neutrophils

Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane

This is an author created, un-copyedited version of an article published in The Astronomical Journal. Under embargo. Embargo end date: 27 March 2018. IOP Publishing is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: https://doi.org/10.3847/1538-3881/aa5be4.Deep near-IR images from the VISTA Variables in the Vía Láctea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a thin slice of the fourth Galactic quadrant (295° < ℓ < 350°, −2°.24 < b < −1°.05). The sample’s distance distribution exhibits a maximum density that occurs at the bulge tangent point, which implies that this primarily Oosterhoff type I population of RRab stars does not trace the bar delineated by their red clump counterparts. The bulge RR Lyrae population does not extend beyond ℓ ∼ 340°, and the sample’s spatial distribution presents evidence of density enhancements and substructure that warrants further investigation. Indeed, the sample may be employed to evaluate Galactic evolution models, and is particularly lucrative since half of the discovered RR Lyrae are within reach of Gaia astrometric observations.Peer reviewedFinal Accepted Versio

Perturbation of the Dimer Interface of Triosephosphate Isomerase and its Effect on Trypanosoma cruzi

Most of the enzymes of parasites have their counterpart in the host. Throughout evolution, the three-dimensional architecture of enzymes and their catalytic sites are highly conserved. Thus, identifying molecules that act exclusively on the active sites of the enzymes from parasites is a difficult task. However, it is documented that the majority of enzymes consist of various subunits, and that conservation in the interface of the subunits is lower than in the catalytic site. Indeed, we found that there are significant differences in the interface between the two subunits of triosephosphate isomerase from Homo sapiens and Trypanosoma cruzi (TcTIM), which causes Chagas disease in the American continent. In the search for agents that specifically inhibit TcTIM, we found that 2,2′-dithioaniline (DTDA) is far more effective in inactivating TcTIM than the human enzyme, and that its detrimental effect is due to perturbation of the dimer interface. Remarkably, DTDA prevented the growth of Escherichia coli cells that had TcTIM instead of their own TIM and killed T. cruzi epimastigotes in culture. Thus, this study highlights a new approach base of targeting molecular interfaces of dimers

A prospective cohort study to assess seroprevalence, incidence, knowledge, attitudes and practices, willingness to pay for vaccine and related risk factors in dengue in a high incidence setting

Abstract Background Dengue is one of the most important vector-borne diseases in the world, causing significant morbidity and economic impact. In Colombia, dengue is a major public health problem. Departments of La Guajira, Cesar and Magdalena are dengue endemic areas. The objective of this research is to determine the seroprevalence and the incidence of dengue virus infection in the participating municipalities from these Departments, and also establish the association between individual and housing factors and vector indices with seroprevalence and incidence. We will also assess knowledge, attitudes and practices, and willingness-to-pay for dengue vaccine. Methods A cohort study will be assembled with a clustered multistage sampling in 11 endemic municipalities. Approximately 1000 homes will be visited to enroll people older than one year who living in these areas, who will be followed for 1 year. Dengue virus infections will be evaluated using IgG indirect ELISA and IgM and IgG capture ELISA. Additionally, vector indices will be measured, and adult mosquitoes will be captured with aspirators. Ovitraps will be used for continuous estimation of vector density. Discussion This research will generate necessary knowledge to design and implement strategies with a multidimensional approach that reduce dengue morbidity and mortality in La Guajira and other departments from Colombian Caribbean

Database of spatial distribution of non indigenous species in Spanish marine waters

Research in marine Spanish waters are focused on several actions to achieve an effectively management on protected areas, with the active participation of the stakeholders and research as basic tools for decision-making. Among these actions, there is one about the knowledge and control on NIS. One of its objectives is the creation of NIS factsheets, which are going to be added to the National Marine Biodiversity Geographical System (GIS) providing complementary information about taxonomic classification, common names, taxonomic synonyms, species illustrations, identification morphological characters, habitat in the native and introduced regions, biological and ecological traits, GenBank DNA sequences, world distribution, first record and evolution in the introduced areas, likely pathways of introduction, effects in the habitats and interaction with native species, and potential management measures to apply. The database will also provide data for (1) the European online platforms, (2) the environmental assessment for the Descriptor 2 (D2-NIS) of the EU Marine Strategy Framework Directive (MSFD), as well as (3) supporting decisions made by stakeholders. It is the result of extensive collaboration among scientist, manager’s and citizen science in the Spanish North-Atlantic, South-Atlantic, Gibraltar Strait-Alboran, Levantine-Balearic and Canary Islands marine divisions, providing an updated overview of the spatial distribution of relevant extended and invasive NIS of recent and established NIS introduced by maritime transport and aquaculture pathways, as well as on cryptogenic or native species in expansion due to the climatic water warming trend