Artículos (Microbiología)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10904

Examinar

Mostrando 1 - 20 de 378

Implicación de un brote nacional de infección por Serratia marcescens asociado a clorhexidina contaminada en un hospital pediátrico
(Elsevier, 2017-05-30) Morillo García, Áurea ; Torres Sánchez, María José; Alonso Salas , María Teresa; Conde Herrera, Manuel; Aznar Martín, Javier; Universidad de Sevilla. Departamento de Microbiología
La ubicuidad de Serratia marcescens, su capacidad de sobrevivir en ambientes húmedos, así como de colonizar el tracto gastrointestinal y/o respiratorio, la hace responsable de múltiples brotes nosocomiales1, sobre todo en pacientes pediátricos, concretamente, recién nacidos, quienes sufren las peores consecuencias2, 3. En ocasiones se localiza la fuente de infección, siendo de especial trascendencia, por sus consecuencias, aquellos brotes en los que está implicada una solución antiséptica3. En esta carta describimos la experiencia en un hospital infantil (HI), en el contexto de un brote nacional por S. marcescens asociado al uso de un antiséptico de clorhexidina (CHX) contaminado4, entre agosto de 2014 y enero de 2015, con 148 casos (86 confirmados) en 10 CC.AA. Aunque la mayoría de los afectados tenían más de 65 años, en nuestro centro se vieron afectados 8 niños, entre el 22 de noviembre y 16 de diciembre de 2014. Todos desarrollaron bacteriemia con buena evolución, excepto un lactante que falleció en 24 horas tras el diagnóstico (letalidad 12,5%). (estracto)
Effect of RecA inactivation on quinolone susceptibility and the evolution of resistance in clinical isolates of Escherichia coli
(Oxford Academic, 2021-02) Machuca, J.; Recacha, E.; Gallego-Mesa, B.; Díaz Díaz, S.; Rojas-Granado, G.; García Duque, A.; Docobo Pérez, Fernando; Pascual Hernández, Álvaro; Rodríguez Martínez, José Manuel; Universidad de Sevilla. Departamento de Microbiología; Instituto de Biomedicina de Sevilla (IBIS); Instituto de Salud Carlos III; European Union (UE); Universidad de Sevilla. CTS210: Resistencia a Antimicrobianos
Background: SOS response suppression (by RecA inactivation) has been postulated as a therapeutic strategy for potentiating antimicrobials against Enterobacterales. Objectives: To evaluate the impact of RecA inactivation on the reversion and evolution of quinolone resistance using a collection of Escherichia coli clinical isolates. Methods: Twenty-three E. coli clinical isolates, including isolates belonging to the high-risk clone ST131, were included. SOS response was suppressed by recA inactivation. Susceptibility to fluoroquinolones was determined by broth microdilution, growth curves and killing curves. Evolution of quinolone resistance was evaluated by mutant frequency and mutant prevention concentration (MPC). Results: RecA inactivation resulted in 2–16-fold reductions in fluoroquinolone MICs and modified EUCAST clinical category for several isolates, including ST131 clone isolates. Growth curves and time–kill curves showed a clear disadvantage (up to 10 log10 cfu/mL after 24 h) for survival in strains with an inactivated SOS system. For recA-deficient mutants, MPC values decreased 4–8-fold, with values below the maximum serum concentration of ciprofloxacin. RecA inactivation led to a decrease in mutant frequency (≥103-fold) compared with isolates with unmodified SOS responses at ciprofloxacin concentrations of 4×MIC and 1 mg/L. These effects were also observed in ST131 clone isolates. Conclusions: While RecA inactivation does not reverse existing resistance, it is a promising strategy for increasing the effectiveness of fluoroquinolones against susceptible clinical isolates, including high-risk clone isolates.
Role of inorganic phosphate concentrations in in vitro activity of fosfomycin
(Elsevier, 2022-02) Ortiz Padilla, Miriam; Portillo Calderón, Inés María; Maldonado, Natalia; Rodríguez Martínez, José Manuel; De Gregorio Iaria, Belén; Merino Bohórquez, Vicente; Rodríguez-Baño, Jesús; Pascual Hernández, Álvaro; Docobo Pérez, Fernando; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Genética; Universidad de Sevilla. Departamento de Farmacología; Universidad de Sevilla. Departamento de Medicina; Instituto de Biomedicina de Sevilla (IBIS); Instituto de Salud Carlos III; European Union (UE); Universidad de Sevilla. BIO116: Genética Bacteriana; Universidad de Sevilla. CTS210: Resistencia a Antimicrobianos
Objectives: The objective of this study was to evaluate the in vitro activity of fosfomycin under different physiological concentrations of inorganic phosphate (Pi). Methods: The wild-type BW25113 strain, four isogenic mutants (ΔglpT, ΔuhpT, ΔglpT-uhpT, and ΔphoB) and six clinical isolates of Escherichia coli with different fosfomycin susceptibilities were used. EUCAST breakpoints were used. Susceptibility was evaluated by agar dilution using standard Mueller–Hinton agar (Pi concentration of 1 mM similar to human plasma concentration) and supplemented with Pi (13 and 42 mM, minimum and maximum urinary Pi concentrations) and/or glucose-6-phosphate (25 mg/L). Fosfomycin transporter promoter activity was assayed using PglpT::gfpmut2 or PuhpT::gfpmut2 promoter fusions in standard Mueller–Hinton Broth (MHB), supplemented with Pi (13 or 42 mM) ± glucose-6-phosphate. Fosfomycin activity was quantified, estimating fosfomycin EC50 under different Pi concentrations (1, 13 and 42 mM + glucose-6-phosphate) and in time–kill assays using fosfomycin concentrations of 307 (maximum plasma concentration (Cmax)), 1053 and 4415 mg/L (urine Cmax range), using MHB with 28 mM Pi (mean urine Pi concentration) + 25 mg/L glucose-6-phosphate. Results: All the strains showed decreased susceptibility to fosfomycin linked to increased Pi concentrations: 1–4 log2 dilution differences from 1 to 13 mM, and 1–8 log2 dilution differences at 42 mM Pi. Changes in phosphate concentration did not affect the expression of fosfomycin transporters. By increasing Pi concentrations higher fosfomycin EC50 bacterial viability was observed, except against ΔglpT-uhpT. The increase in Pi reduced the bactericidal effect of fosfomycin. Discussion: Pi variations in physiological fluids may reduce fosfomycin activity against E. coli. Elevated Pi concentrations in urine may explain oral fosfomycin failure in non-wild-type but fosfomycin-susceptible E. coli strains.
Higher prevalence of CTX-M-27-producing Escherichia coli belonging to ST131 clade C1 among residents of two long-term care facilities in Southern Spain
(Springer Nature, 2022) López Cerero, Lorena; Salamanca, Elena; Delgado Valverde, María Mercedes; Rodríguez Martínez, José Manuel; Rodríguez-Baño, Jesús; Pascual Hernández, Álvaro; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Medicina; Instituto de Biomedicina de Sevilla (IBIS); Instituto de Salud Carlos III; Ministerio de Economía y Competitividad (MINECO). España; European Union (UE); Universidad de Sevilla. CTS210: Resistencia a Antimicrobianos
Recently, the emergence of an international lineage of the CTX-M-27-producing clade C1 of Escherichia coli ST131 is being observed. The aim is to see if this strain has also been introduced in our area. Twenty-eight (33%) out of 86 individuals from two LTCFs in Seville were found to be colonized with fluoroquinolone-resistant E. coli ST131 and 46% isolates were ESBL/pAmpC producers. C1 isolates were more common than C2 and more frequently produced blaESBL/pAmpC genes (53% vs 33%). Strain sharing was observed in 6 groups of 2–5 cases (61%). A differentiated cluster of 5 C1-CTX-M-27 isolates was found which lacked the M27PP1 region.
The mef(A)/msr(D)-carrying streptococcal prophage Φ1207.3 encodes an SOS-like system, induced by UV-C light, responsible for increased survival and increased mutation rate
(ASM Journals, 2023-09-12) Fox, Valeria; Santoro, Francesco; Apicella, Carmen; Díaz Díaz, Sara; Rodríguez Martínez, José Manuel; Iannelli, Francesco; Pozzi, Gianni; Universidad de Sevilla. Departamento de Microbiología; Instituto de Biomedicina de Sevilla (IBIS); Universidad de Sevilla. CTS210: Resistencia a Antimicrobianos
Bacterial SOS response is an inducible system of DNA repair and mutagenesis. Streptococci lack a canonical SOS response, but an SOS-like response was reported in some species. The mef(A)-msr(D)-carrying prophage Ф1207.3 of Streptococcus pyogenes contains a region, spanning orf6 to orf11, showing homology to characterized streptococcal SOS-like cassettes. Genome-wide homology search showed the presence of the whole Φ1207.3 SOS-like cassette in three S. pyogenes prophages, while parts of it were found in other bacterial species. To investigate whether this cassette confers an SOS-mutagenesis phenotype, we constructed Streptococcus pneumoniae R6 isogenic derivative strains: (i) FR172, streptomycin resistant, (ii) FR173, carrying Φ1207.3, and (iii) FR174, carrying a recombinant Φ1207.3, where the SOS-like cassette was deleted. These strains were used in survival and mutation rate assays using a UV-C LED instrument, for which we designed and 3D-printed a customized equipment, constituted of an instrument support and swappable-autoclavable mini-plates and lids. Upon exposure to UV fluences ranging from 0 to 6,400 J/m2 at four different wavelengths, 255, 265, 275, and 285 nm, we found that the presence of Φ1207.3 SOS-like cassette increases bacterial survival up to 34-fold. Mutation rate was determined by measuring rifampicin resistance acquisition upon exposure to UV fluence of 50 J/m2 at the four wavelengths by fluctuation test. The presence of Φ1207.3 SOS-like cassette resulted in a significant increase in the mutation rate (up to 18-fold) at every wavelength. In conclusion, we demonstrated that Φ1207.3 carries a functional SOS-like cassette responsible for an increased survival and increased mutation rate in S. pneumoniae. IMPORTANCE: Bacterial mutation rate is generally low, but stress conditions and DNA damage can induce stress response systems, which allow for improved survival and continuous replication. The SOS response is a DNA repair mechanism activated by some bacteria in response to stressful conditions, which leads to a temporary hypermutable phenotype and is usually absent in streptococcal genomes. Here, using a reproducible and controlled UV irradiation system, we demonstrated that the SOS-like gene cassette of prophage Φ1207.3 is functional, responsible for a temporary hypermutable phenotype, and enhances bacterial survival to UV irradiation. Prophage Φ1207.3 also carries erythromycin resistance genes and can lysogenize different pathogenic bacteria, constituting an example of a mobile genetic element which can confer multiple phenotypes to its host.
Activity of Fosfomycin and Amikacin against Fosfomycin-Heteroresistant Escherichia coli Strains in a Hollow-Fiber Infection Model
(ASM Journals, 2021-04-19) Portillo Calderón, I.; Ortiz Padilla, Miriam; De Gregorio Iaria, Belén; Merino Bohórquez, Vicente; Blázquez, J.; Rodríguez-Baño, Jesús; Rodríguez Martínez, José Manuel; Pascual Hernández, Álvaro; Docobo Pérez, Fernando; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Genética; Universidad de Sevilla. Departamento de Farmacología; Universidad de Sevilla. Departamento de Medicina; Instituto de Biomedicina de Sevilla (IBIS); Universidad de Sevilla. BIO116: Genética Bacteriana; Universidad de Sevilla. CTS210: Resistencia a Antimicrobianos
We evaluated human-like the efficacy of intravenous doses of fosfomycin of 8 g every 8 h (8 g/Q8h) and of amikacin (15 mg/kg/Q24h) in monotherapy and in combination against six fosfomycin-heteroresistant Escherichia coli isolates using a hollow-fiber infection model (HFIM). Six fosfomycin-heteroresistant E. coli isolates (four with strong mutator phenotype) and the control strain E. coli ATCC 25922 were used. Mutant frequencies for rifampin (100 mg/liter), fosfomycin (50 and 200 mg/liter), and amikacin (32 mg/liter) were determined. Fosfomycin and amikacin MICs were assessed by agar dilution (AD), gradient strip assay (GSA), and broth microdilution (BMD). Fosfomycin and amikacin synergies were studied by checkerboard and time-kill assays at different concentrations. The efficacies of fosfomycin (8 g/Q8h) and amikacin (15 mg/kg/Q24h) alone and in combination were assessed using an HFIM. Five isolates were determined to be resistant to fosfomycin by AD and BMD, but all were determined to be susceptible by GSA. All isolates were determined to be susceptible to amikacin. Antibiotic combinations were synergistic in two isolates, and no antagonism was detected. In time-kill assays, all isolates survived under fosfomycin at 64 mg/liter, although at 307 mg/liter only the normomutators and two hypermutators survived. Four isolates survived under 16 mg/liter amikacin, and none survived at 45 mg/liter. No growth was detected under combination conditions. In HFIM, fosfomycin and amikacin monotherapies failed to sterilize bacterial cultures; however, the combination of fosfomycin and amikacin yielded a rapid eradication. There may be a risk of treatment failure of fosfomycin-heteroresistant E. coli isolates using either amikacin or fosfomycin in monotherapy. These results support that the amikacin-fosfomycin combination can rapidly decrease bacterial burden and prevent the emergence of resistant subpopulations against fosfomycin-heteroresistant strains.
Vaccines for Antibiotic-Resistant Bacteria: Possibility or Pipe Dream?
(Elsevier, 2016-02) García Quintanilla, Meritxell de Jesús; Pulido, Marina R.; Carretero Ledesma, Marta; McConnell, Michael J.; Universidad de Sevilla. Departamento de Microbiología; Centro para el Desarrollo Tecnologlco Industrial; European Regional Development Fund \'A Way to Achieve Europe\'; Ministerio de Economia, Industria y Competitividad (MINECO). España; Instituto de Salud Carlos III; Spanish Network for Research in Infectious Diseases; Universidad de Sevilla. CTS210: Resistencia a Antimicrobianos
The increasing incidence of infections caused by antibiotic-resistant bacteria from multiple species, together with the paucity of new antibiotics in the development pipeline, indicates that vaccines could play a role in combating these infections. The development of vaccines for these infections presents unique challenges related to target population selection, vaccine administration, and antigen identification. Advances in genomic, transcriptomic, and proteomic technologies offer great potential for identifying promising antigens that are highly conserved and expressed during human infections. Although important challenges remain, the potential health and economic benefits associated with the clinical implementation of vaccination strategies for the prevention of antibiotic-resistant infections warrant their continued development.
The Type VI Secretion System of Sinorhizobium fredii USDA257 Is Required for Successful Nodulation With Glycine max cv Pekin
(John Wiley & Sons Ltd, 2025-03-02) Reyes Pérez, Pedro José; Jiménez Guerrero, Irene; Sánchez Reina, Ana; Civantos Jiménez, Cristina; Moreno De Castro, Natalia; Ollero Márquez, Francisco Javier; Gandullo Tovar, Jacinto Manuel; Bernal Guzmán, Patricia; Pérez Montaño, Francisco de Asís; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Biología Vegetal y Ecología; Ministerio de Ciencia, Innovación y Universidades (MICIU). España
The symbiotic relationship between rhizobia and legumes is critical for sustainable agriculture and has important economic and environmental implications. In this intricate process, rhizobial bacteria colonise plant roots and induce the formation of specialised plant organs, the nodules. Within these structures, rhizobia fix environmental nitrogen into ammonia, significantly reducing the demand for synthetic fertilisers. Multiple bacterial secretion systems (TXSS, Type X Secretion System) are involved in establishing this symbiosis, with T3SS being the most studied. While the Type 6 Secretion System (T6SS) is known as a “nanoweapon” commonly used by diderm (formerly gram-negative) bacteria for inter-bacterial competition and potentially manipulating eukaryotic cells, its precise role in legume symbiosis remains unclear. Sinorhizobium fredii USDA257, a fast-growing rhizobial strain capable of nodulating diverse legume plants, possesses a single T6SS cluster containing genes encoding structural components and potential effectors that could target plant cells and/or act as effector-immunity pairs. Our research reveals that this T6SS can be induced in nutrient-limited conditions and, more importantly, is essential for successful nodulation and competitive colonisation of Glycine max cv Pekin. Although the system did not demonstrate effectiveness in eliminating competing bacteria in vitro, its active presence within root nodules suggests a sophisticated role in symbiotic interactions that extends beyond traditional interbacterial competition.
Identifying targets for antibiotic development using omics technologies
(Elsevier, 2016-03) Pulido, Marina R.; García Quintanilla, Meritxell de Jesús; Gil Marqués, María Luisa; McConnell, Michael J.; Universidad de Sevilla. Departamento de Microbiología; Ministerio de Economia, Industria y Competitividad (MINECO). España; Instituto de Salud Carlos III; Universidad de Sevilla. CTS210: Resistencia a Antimicrobianos
The lack of new compounds in the antibiotic development pipeline together with the increasing incidence of infections caused by antibiotic-resistant bacteria on a global scale represents an alarming public health problem. Advances in genomic, transcriptomic and proteomic technologies permit the characterization of bacterial physiology at an unprecedented scale, and thus can facilitate the identification of bacterial factors that could serve as targets for the development of new antibiotics. Recent studies employing these technologies have permitted the elucidation of key components in multiple bacterial processes such as bacterial survival, persistence in the host and infection. The continued use of these approaches and the incorporation of emerging omics technologies hold great potential in elucidating high value targets for antibiotic development.
Sinorhizobium Fredii HH103 flgJ is a Flagellar Gene Induced by Genistein in a NodD1- and TtsI- Dependent Manner
(Springer Science and Business Media Deutschland GmbH, 2024) Navarro Gómez, Pilar; Alias Villegas, Cynthia; Jiménez Guerrero, Irene; Fuentes Romero, Francisco; López Baena, Francisco Javier; Acosta Jurado, Sebastián; Vinardell González, José María; Universidad de Sevilla. Departamento de Microbiología; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla
Background and aims: Sinorhizobium fredii HH103 is a broad host-range rhizobial strain able to induce the formation of nitrogen-fixing nodules in dozens of legumes, including soybean. S. fredii HH103 exhibits genistein-induced surface motility. The aim of this work has been to determine whether the flgJ gene, which is inducible by genistein and codes for a flagellar protein, is involved in this motility and is relevant for symbiosis with soybean. Methods: We have generated two independent mutants in the flgJ gene of HH103 and analysed their phenotypes in motility, exopolysaccharide production, biofilm formation, soybean root colonization, symbiosis with soybean, and secretion of effector proteins. We have also further studied the regulation of the expression of flgJ. Results: We show that the expression of flgJ is driven by a tts box previously not detected, which accounts for its induction by flavonoids and the NodD1 and TtsI transcriptional activators. Inactivation of flgJ led to severe impairments in bacterial motility (swimming and genistein-induced surface motility) as well as to a significant reduction in symbiotic performance with soybean when bacteria are not directly inoculated onto the seedling roots. However, the absence of a functional FlgJ protein did not affect the bacterial ability to colonize soybean roots. Conclusion: The flgJ gene of S. fredii HH103 connects the nod regulon with the genistein-induced surface motility exhibited by this rhizobial strain.
White Paper: Bridging the gap between surveillance data and antimicrobial stewardship in the outpatient sector—practical guidance from the JPIAMR ARCH and COMBACTE-MAGNET EPI-Net networks
(Oxford Academic, 2020) Arieti, Fabiana; Göpel, Siri; Sibani, Marcella; Carrara, Elena; Pezzani, Maria Diletta; Murri, Rita; Mutters, Nico T.; López Cerero, Lorena; Voss, Andreas; Cauda, Roberto; Tacconelli, Evelina; Universidad de Sevilla. Departamento de Microbiología; European Union (UE); e German Federal Ministry of Education and Research (BMBF)
Background: The outpatient setting is a key scenario for the implementation of antimicrobial stewardship (AMS) activities, considering that overconsumption of antibiotics occursmainly outside hospitals. This publication is the result of a joint initiative by the JPIAMR ARCH and COMBACTE-MAGNET EPI-Net networks, which is aimed at formulating a set of target actions for linking surveillance data with AMS activities in the outpatient setting. Methods: A scoping review of the literature was carried out in three research areas: AMS leadership and accountability; antimicrobial usage and AMS; antimicrobial resistance and AMS. Consensus on the actions was reached through a RAND-modified Delphi process involving over 40 experts in infectious diseases, clinical microbiology, AMS, veterinary medicine or public health, from18 low-, middle- and high-income countries. Results: Evidence was retrieved from 38 documents, and an initial 25 target actions were proposed, differentiating between essential or desirable targets according to clinical relevance, feasibility and applicability to settings and resources. In the first consultation round, preliminary agreement was reached for all targets. Further to a second review, 6 statements were re-considered and 3 were deleted, leading to a final list of 22 target actions in the form of a practical checklist. Conclusions: This White Paper is a pragmatic and flexible tool to guide the development of calibrated surveillance-based AMS interventions specific to the outpatient setting, which is characterized by substantial inter- and intra-country variability in the organization of healthcare structures, maintaining a global perspective and taking into account the feasibility of the target actions in low-resource settings.
The Imperative for Quality Control Programs in Monkeypox virus DNA Testing by PCR: CIBERINFEC Quality Control
(John Wiley & Sons, 2023) de Salazar, Adolfo; Martínez, Miguel J.; Navero Castillejos, Jessica; Negredo, Anabel; Galán, Juan Carlos; Rojo Molinero, Estrella; Lagarejos, Eduardo; Muñoz Almagro, Carmen; Hernández Rodríguez, Águeda; Lepe Jiménez, José Antonio; Sánchez-Seco Fariñas, María Paz; Universidad de Sevilla. Departamento de Microbiología; Instituto de Salud Carlos III
To evaluate molecular assays for Mpox diagnosis available in various clinical microbiology services in Spain through a quality control (QC) approach. A total of 14 centers from across Spain participated in the study. The Reference Laboratory dispatched eight serum samples and eight nucleic acid extracts to each participating center. Some samples were spiked with Mpox or Vaccinia virus to mimic positive samples for Mpox or other orthopox viruses. Participating centers provided information on the results obtained, as well as the laboratory methods used. Among the 14 participating centers seven different commercial assays were employed, with the most commonly used kit being LightMix Modular Orthopox/Monkeypox (Mpox) Virus (Roche®). Of the 12 centers conducting Mpox determinations, concordance ranged from 62.5% (n = 1) to 100% (n = 11) for eluates and from 75.0% (n = 1) to 100% (n = 10) for serum. Among the 10 centers performing Orthopoxvirus determinations, a 100% concordance was observed for eluates, while for serum, concordance ranged from 87.5% (n = 6) to 100% (n = 4). Repeatedly, 6 different centers reported a false negative in serum samples for Orthopoxvirus diagnosis, particularly in a sample with borderline Ct = 39. Conversely, one center, using the TaqMan™ Mpox Virus Microbe Detection Assay (Thermo Fisher), reported false positives in Mpox diagnosis for samples spiked with vaccinia virus due to cross-reactions. We observed a positive correlation of various diagnostic assays for Mpox used by the participating centers with the reference values. Our results highlight the significance of standardization, validation, and ongoing QC in the microbiological diagnosis of infectious diseases, which might be particularly relevant for emerging viruses.
Safety of Early Oral Ambulatory Treatment of Adult Patients with Bloodstream Infections Discharged from the Emergency Department
(American Society for Microbiology, 2023) Casado, Ana; Gimeno, Adelina; Aguilar Guisado, Manuela; García, Manuel; Rodríguez, Jesús Francisco; Rivas, Pedro Antonio; Bueno, Claudio; Lepe Jiménez, José Antonio; Cisneros, José Miguel; Molina, Jose; Universidad de Sevilla. Departamento de Medicina; Universidad de Sevilla. Departamento de Microbiología
This study evaluates the safety of early oral ambulatory treatment of adult patients diagnosed with bacteremia after their discharge from the emergency department. A cohort of 206 febrile ambulatory patients was assessed. Bacteremic low-risk patients were recommended an oral treatment and were compared with matched febrile non-bacteremic outpatients. Rates of 14-day mortality and unplanned re-consultations were similar and below 5% in both cohorts, highlighting the safety of oral therapy of low-risk bacteremia, even from its onset.
Enhanced porous titanium biofunctionalization based on novel silver nanoparticles and nanohydroxyapatite chitosan coatings
(Elsevier, 2025-04) Castillejo, Ana; Martínez Muñoz, Guillermo; Delgado-Pujol, Ernesto J.; Villalobo Polo, Eduardo; Carrillo de la Fuente, Francisco; Casado Jurado, David; Pérez Bernal, Juan Luis; Begines Ruiz, Belén; Torres Hernández, Yadir; Alcudia Cruz, Ana; Universidad de Sevilla. Departamento de Química Orgánica y Farmacéutica; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Química Analítica; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. Departamento de Microbiología; Ministerio de Ciencia e Innovación (MICIN). España
Titanium is widely used for implants however it presents limitations such as infection risk, stress shielding phenomenon, and poor osseointegration. To address these issues, a novel approach was proposed that involves fabricating porous titanium substrates, to reduce implant stiffness, minimizing stress shielding and bone resorption, and applying polymeric coatings to improve bioactivity. Composite coating prepared from chitosan, silver nanoparticles, and nanohydroxyapatite was optimized to enhance antibacterial properties and promote osseointegration. Chitosan with 80.5 % of deacetylation degree was used to prepare composites with diverse compositions, including different methodologies of adding silver nanoparticles, with silver concentrations below toxic level. Antibacterial activity was tested with three different strains, including Gram+ and Gram− bacteria, demonstrating excellent inhibition after 21 days. In addition, the induction of hydroxyapatite formation was investigated. Finally, the optimal porous metallic substrate that exhibited a more suitable stiffness (29 GPa) (close to the cortical bone tissue they intend to replace) was chosen to be infiltrated with the selected composites. In summary, this synergistic approach based on the combination of porous titanium substrates with 60 vol% porosity and a 355–500 μm pore size distribution coated with 3%CS-nHA-AgNPs-TPP-AgNPsbath composite provided a potential solution to provide implants with improved biomechanical balance and biofunctionality.
Estudio de estabilidad fisicoquímica y microbiológica de 2 nuevos colirios de metilprednisolona sin conservantes
(Elsevier, 2024-07-09) Merino Bohórquez, Vicente; Berisa Prado, Silvia; Delgado Valverde, María Mercedes; Tirado Pérez, María José; García Palomo, Marta; Alonso Herreros, José María; Dávila Pousa, María del; Universidad de Sevilla. Departamento de Farmacología; Universidad de Sevilla. Departamento de Microbiología; Sociedad Española de Farmacéuticos Hospitalarios
Objetivo Estudiar la estabilidad fisicoquímica y microbiológica de dos colirios de metilprednisolona succinato sódico (MTPSS) a 1 mg/mL y 10 mg/mL sin conservantes durante 90 días para su uso en patologías oculares como el síndrome de Sjögren y el síndrome del ojo seco. Método los dos colirios se elaboraron partiendo de MTPSS inyectable (Solu-moderin® y Urbason®), agua para inyectables y suero salino fisiológico. Posteriormente se almacenaron, según normas ICH (International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use) por triplicado en condiciones de refrigeración (5 ± 3 °C), temperatura ambiente (25 ± 2 °C) y a 40 °C (± 2 °C). De acuerdo con la USP (United States Pharmacopeia), se realizaron controles fisicoquímicos de contenido en principio activo por HPLC-UV (High Performance Liquid Chromatography-Ultraviolet detector), control de pH, control de osmolalidad y controles visuales. Además, se realizó un estudio de esterilidad microbiológica en las condiciones de refrigeración, tanto en envases abiertos (hasta 30 días), como en envases cerrados (hasta 90 días). Resultados Los colirios almacenados a 5 °C fueron los más estables y el principio activo se degradó por debajo del 90% a partir del día 21 en el colirio a 1 mg/mL.y a partir del día 42 en el colirio a 10 mg/mL. La variación del pH no fue ≥ 1 unidad en las formulaciones almacenadas a 5 °C, al contrario que en el resto. La osmolalidad no presentó cambios superiores al 5% a día 90 en ninguna de las condiciones de almacenamiento. Las muestras de los colirios a 10 mg/mL no refrigerados presentaron un precipitado blanco a partir del día 14 y 28 respectivamente. Los colirios a 1 mg/mL no refrigerados presentaron partículas en suspensión el día 90. No hubo cambios de color. El análisis microbiológico demostró esterilidad durante los 90 días en los envases cerrados, pero en los abiertos se detectó contaminación microbiana a partir del día 21. Conclusiones Los colirios de MTPSS a 1 mg/mL presentan una estabilidad fisicoquímica y microbiológica de 21 días en refrigeración, frente a los 42 días que admiten los colirios a 10 mg/mL almacenados bajo las mismas condiciones. No obstante, al no incluir conservantes en su composición, no se deben utilizar durante más de 7 días desde su apertura.
Extracellular Vesicle-Driven Crosstalk between Legume Plants and Rhizobia: The Peribacteroid Space of Symbiosomes as a Protein Trafficking Interface
(American Chemical Society, 2024-12-12) Ayala García, Paula; Herrero Gómez, Irene; Jiménez Guerrero, Irene; Otto, Viktoria; Moreno De Castro, Natalia; Musken, Mathias; Jansch, Lothar; van Ham, Marco; Vinardell González, José María; López Baena, Francisco Javier; Ollero Márquez, Francisco Javier; Pérez Montaño, Francisco de Asís; Borrero de Acuña, José Manuel; Universidad de Sevilla. Departamento de Microbiología; Junta de Andalucía; Ministerio de Ciencia e Innovación (MICIN). España
Prokaryotes and eukaryotes secrete extracellular vesicles (EVs) into the surrounding milieu to preserve and transport elevated concentrations of biomolecules across long distances. EVs encapsulate metabolites, DNA, RNA, and proteins, whose abundance and composition fluctuate depending on environmental cues. EVs are involved in eukaryote-to-prokaryote communication owing to their ability to navigate different ecological niches and exchange molecular cargo between the two domains. Among the different bacterium-host relationships, rhizobium-legume symbiosis is one of the closest known to nature. A crucial developmental stage of symbiosis is the formation of N2-fixing root nodules by the plant. These nodules contain endocytosed rhizobia─called bacteroids─confined by plant-derived peribacteroid membranes. The unrestricted interface between the bacterial external membrane and the peribacteroid membrane is the peribacteroid space. Many molecular aspects of symbiosis have been studied, but the interbacterial and interdomain molecule trafficking by EVs in the peribacteroid space has not been questioned yet. Here, we unveil intensive EV trafficking within the symbiosome interface of several rhizobium-legume dual systems by developing a robust EV isolation procedure. We analyze the EV-encased proteomes from the peribacteroid space of each bacterium-host partnership, uncovering both conserved and differential traits of every symbiotic system. This study opens the gates for designing EV-based biotechnological tools for sustainable agriculture.
The Sinorhizobium (Ensifer) fredii HH103 Type 3 Secretion System Suppresses Early Defense Responses to Effectively Nodulate Soybean
(American Phytopathological Society, 2015-07-06) Jiménez Guerrero, Irene; Pérez Montaño, Francisco de Asís; Monreal Hermoso, José Antonio; Preston, Gail M.; Fones, Helen; Vioque, Blanca; Ollero Márquez, Francisco Javier; López Baena, Francisco Javier; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Biología Vegetal y Ecología; Junta de Andalucía; Ministerio de Economía y Competitividad (MINECO). España; Universidad de Sevilla
Plants that interact with pathogenic bacteria in their natural environments have developed barriers to block or contain the infection. Phytopathogenic bacteria have evolved mechanisms to subvert these defenses and promote infection. Thus, the type 3 secretion system (T3SS) delivers bacterial effectors directly into the plant cells to alter host signaling and suppress defenses, providing an appropriate environment for bacterial multiplication. Some rhizobial strains possess a symbiotic T3SS that seems to be involved in the suppression of host defenses to promote nodulation and determine the host range. In this work, we show that the inactivation of the Sinorhizobium (Ensifer) fredii HH103 T3SS negatively affects soybean nodulation in the early stages of the symbiotic process, which is associated with a reduction of the expression of early nodulation genes. This symbiotic phenotype could be the consequence of the bacterial triggering of soybean defense responses associated with the production of salicylic acid (SA) and the impairment of the T3SS mutant to suppress these responses. Interestingly, the early induction of the transcription of GmMPK4, which negatively regulates SA accumulation and defense responses in soybean via WRKY33, could be associated with the differential defense responses induced by the parental and the T3SS mutant strain.
Competition for alfalfa nodulation under metal stress by the metal-tolerant strain Ochrobactrum cytisi Azn6.2
(Wiley, 2019-09) Navarro Torre, Salvadora; Rodríguez Llorente, Ignacio David; Doukkali, Bouchra; Caviedes Formento, Miguel Ángel; Pajuelo Domínguez, Eloísa; Universidad de Sevilla. Departamento de Microbiología; Junta de Andalucía; Ministerio de Ciencia e Innovación (MICIN). España
Legume plants, in association with rhizobia, are gaining increasing interest for heavy metal rhizoremediation. This symbiotic interaction combines the advantages of rhizoremediation and soil nitrogen enrichment. In metal polluted soils, Ochrobactrum cytisi can elicit non-fixing nodules on legumes, including Medicago sativa. Nodulation kinetics was much slower when M. sativa plants were inoculated with O. cytisi Azn6.2 compared with the natural symbiont Ensifer meliloti 1021 and nodules were ineffective in nitrogen fixation. A competition experiment was performed using alfalfa grown on heavy metals, and co-inoculated with equal amounts of the metal-sensitive E. meliloti 1021 and the metal-resistant O. cytisi Azn6.2. When plants were inoculated in non-polluted substrates, all nodules were formed by E. meliloti 1021. Nevertheless, under increasing metal concentrations, the number of nodules occupied by O. cytisi grew. At the highest metal concentration, all nodules were elicited by O. cytisi, suggesting that the resistant species can take the place of the natural symbiont. This fact has important ecological and environmental implications when proposing legume–rhizobia symbioses for rhizoremediation and highlights the need of selecting highly resistant rhizobia in order to be competitive in polluted soils.
Moving Closer Towards Restoration of Contaminated Estuaries: Bioaugmentation with Autochthonous Rhizobacteria Improves Metal Rhizoaccumulation in Native Spartina Maritima
(Elsevier, 2015) Mesa Marín, Jennifer; Rodríguez Llorente, Ignacio David; Pajuelo Domínguez, Eloísa; Barcia Piedras, José María; Caviedes Formento, Miguel Ángel; Redondo Gómez, Susana; Mateos Naranjo, Enrique; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Biología Vegetal y Ecología; Junta de Andalucía; Ministerio de Educación, Cultura y Deporte (MECD). España
Spartina maritima is an ecosystem engineer that has shown to be useful for phytoremediation purposes. A glasshouse experiment using soil from a metal-contaminated estuary was designed to investigate the effect of a native bacterial consortium, isolated from S. maritima rizhosphere and selected owing to their plant growth promoting properties and multiresistance to heavy metals, on plant growth and metal accumulation. Plants of S. maritima were randomly assigned to three soil bioaugmentation treatments (without inoculation, one inoculation and repeated inoculations) for 30 days. Growth parameters and photosynthetic traits, together with total concentrations of several metals were determined in roots and/or leaves. Bacterial inoculation improved root growth, through a beneficial effect on photosynthetic rate (AN) due to its positive impact on functionality of PSII and chlorophyll concentration. Also, favoured intrinsic water use efficiency of S. maritima, through the increment in AN, stomatal conductance and in root-to-shoot ratio. Moreover, this consortium was able to stimulate plant metal uptake specifically in roots, with increases of up to 19% for As, 65% for Cu, 40% for Pb and 29% for Zn. Thus, bioaugmentation of S. maritima with the selected bacterial consortium can be claimed to enhance plant adaptation and metal rhizoaccumulation during marsh restoration programs.
Deciphering the Role of Plant Growth-promoting Rhizobacteria in the Tolerance of the Invasive Cordgrass Spartina Densiflora to Physicochemical Properties of Salt-marsh Soils
(Springer Nature, 2015) Mateos Naranjo, Enrique; Mesa Marín, Jennifer; Pajuelo Domínguez, Eloísa; Pérez Martín, A.; Caviedes Formento, Miguel Ángel; Rodríguez Llorente, Ignacio David; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Biología Vegetal y Ecología; Junta de Andalucía; Ministerio de Educación, Cultura y Deporte (MECD). España
Background and aims: A glasshouse experiment was conceived to assess the role of a bacterial consortium (Pseudomonas composti SDT3, Aeromonasaquariorum SDT 13 and Bacillus sp. SDT14) isolated from the rizhosphere of S. densiflora on its growth and physiological tolerance to the physicochemical properties of marsh soils. Methods: Two inoculation treatments (with and without inoculation) in combination with two soil types (from Piedras and Odiel marshes, SW Spain) were assigned for 50 days. Growth parameters, combined with measurements of gas exchange, efficiency of PSII biochemistry, photosynthetic pigments and leaf water content were measured. In addition, the accumulation of nutrients and trace elements were determined. Results: The inoculation improved growth of S. densiflora through a beneficial effect on its photochemical apparatus due to its impact on chlorophyll concentration. This enhancement happened under both soil conditions and was mainly reflected in a greater length and diameter of roots. Also, inoculation favoured leaf water content through the decline in stomatal conductance and increment in root-to-shoot ratio. Moreover, this consortium was able to stimulate ion accumulation in roots and leaves. Conclusions: Selected rhizospheric bacteria appear to play a significant role in S. densiflora growth response and tolerance to the physicochemical properties of marshes soils.

Examinar

Envíos recientes