A novel BLUF photoreceptor modulates the Xanthomonas citri subsp. citri-host plant interaction.

Plant-pathogen interaction is influenced by multiple environmental factors, including temperature and light. Recent works have shown that light modulates not only the defense response of plants but also the pathogens virulence. Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker, an important plant disease worldwide. The Xcc genome presents four genes encoding putative photoreceptors: one bacteriophytochrome and three blue light photoreceptors, one LOV and two BLUFs (bluf1: XAC2120 and bluf2: XAC3278). The presence of two BLUFs proteins is an outstanding feature of Xcc. In this work we show that the bluf2 gene is functional. The mutant strain, XccΔbluf2, was constructed demonstrating that BLUF2 regulates swimming-type motility, adhesion to leaves, exopolysaccharide production and biofilm formation, features involved in the Xcc virulence processes. An important aspect during the plant-pathogen interaction is the oxidative response of the host and the consequent reaction of the pathogen. We observed that ROS detoxification is regulated by Xcc bluf2 gene. The phenotypes of disease in orange plants produced by WT and XccΔbluf2 strains were evaluated, observing different phenotypes. Altogether, these results show that BLUF2 negatively regulates virulence during citrus canker. This work constitutes the first report on BLUF-like receptors in plant pathogenic bacteria.

Ready for new waves: optimizing SARS-CoV-2 variants monitoring in pooled samples with droplet digital PCR.

Introduction: The declaration of the end of the Public Health Emergency for COVID-19 on May 11th, 2023, has shifted the global focus led by WHO and CDC towards monitoring the evolution of SARS-CoV-2. Augmenting these international endeavors with local initiatives becomes crucial to not only track the emergence of new variants but also to understand their spread. We present a cost-effective digital PCR-based pooled sample testing methodology tailored for early variant surveillance. Methods: Using 1200 retrospective SARS-CoV-2 positive samples, either negative or positive for Delta or Omicron, we assessed the sensitivity and specificity of our detection strategy employing commercial TaqMan variant probes in a 1:9 ratio of variant-positive to variant-negative samples. Results: The study achieved 100% sensitivity and 99% specificity in 10-sample pools, with an Area Under the Curve (AUC) exceeding 0.998 in ROC curves, using distinct commercial TaqMan variant probes. Discussion: The employment of two separate TaqMan probes for both Delta and Omicron establishes dual validation routes, emphasizing the method's robustness. Although we used known samples to model realistic emergence scenarios of the Delta and Omicron variants, our main objective is to demonstrate the versatility of this strategy to identify future variant appearances. The utilization of two divergent variants and distinct probes for each confirms the method's independence from specific variants and probes. This flexibility ensures it can be tailored to recognize any subsequent variant emergence, given the availability of its sequence and a specific probe. Consequently, our approach stands as a robust tool for tracking and managing any new variant outbreak, reinforcing our global readiness against possible future SARS-CoV-2 waves.

Light modulates important physiological features of Ralstonia pseudosolanacearum during the colonization of tomato plants.

Ralstonia pseudosolanacearum GMI1000 (Rpso GMI1000) is a soil-borne vascular phytopathogen that infects host plants through the root system causing wilting disease in a wide range of agro-economic interest crops, producing economical losses. Several features contribute to the full bacterial virulence. In this work we study the participation of light, an important environmental factor, in the regulation of the physiological attributes and infectivity of Rpso GMI1000. In silico analysis of the Rpso genome revealed the presence of a Rsp0254 gene, which encodes a putative blue light LOV-type photoreceptor. We constructed a mutant strain of Rpso lacking the LOV protein and found that the loss of this protein and light, influenced characteristics involved in the pathogenicity process such as motility, adhesion and the biofilms development, which allows the successful host plant colonization, rendering bacterial wilt. This protein could be involved in the adaptive responses to environmental changes. We demonstrated that light sensing and the LOV protein, would be used as a location signal in the host plant, to regulate the expression of several virulence factors, in a time and tissue dependent way. Consequently, bacteria could use an external signal and Rpsolov gene to know their location within plant tissue during the colonization process.

Comparison of Efficacy of Povidone-Iodine, Ethanol, and an Aerosol Formulation of Silver Sulfadiazine in Controlling Microbial Burden on Sutures From Clean Surgeries.

In the surgical suture, the implanted thread can be a source of microbial contamination. Implanted materials are frequently described as being substrates prone for biofilm development provoking surgical site infections. Treatment of postsurgical wounds with different topical antimicrobial agents is a current practice applied to every patient. However, to date, there is little evidence on the efficacy of different antiseptic treatments on suture materials in preventing environmental or skin bacterial adhesion and further infection. Here, the authors compared the ability of an aerosol formulation of silver sulfadiazine, vitamin A, and lidocaine (AF-SSD) and of two of the most frequently used topical treatments, povidone-iodine and ethanol, in eradicating or controlling the microbial contamination of suture threads in patients who have undergone clean surgeries. Postsurgical suture threads treated with AF-SSD showed a significantly reduced proportion of contaminated samples containing viable microbial cells compared with those treated with povidone-iodine or ethanol. Furthermore, those samples that were positive for bacterial growth showed a lesser number of viable cells in AF-SSD-treated sutures than those treated with povidone-iodine or ethanol. Confocal laser scanning microscopy showed that AF-SSD-treated postsurgical sutures presented significantly less attached microbial cells than povidone-iodine and ethanol, with scarce observable microbial cells on the surface of the suture. Taken together, the results suggest that treatment with AF-SSD is more effective than the other two antiseptics, and there is a potential for improvement in reducing the microbial burden of implanted materials such as the suture thread.

KatE From the Bacterial Plant Pathogen Ralstonia solanacearum Is a Monofunctional Catalase Controlled by HrpG That Plays a Major Role in Bacterial Survival to Hydrogen Peroxide.

Ralstonia solanacearum is the causative agent of bacterial wilt disease on a wide range of plant species. Besides the numerous bacterial activities required for host invasion, those involved in the adaptation to the plant environment are key for the success of infection. R. solanacearum ability to cope with the oxidative burst produced by the plant is likely one of the activities required to grow parasitically. Among the multiple reactive oxygen species (ROS)-scavenging enzymes predicted in the R. solanacearum GMI1000 genome, a single monofunctional catalase (KatE) and two KatG bifunctional catalases were identified. In this work, we show that these catalase activities are active in bacterial protein extracts and demonstrate by gene disruption and mutant complementation that the monofunctional catalase activity is encoded by katE. Different strategies were used to evaluate the role of KatE in bacterial physiology and during the infection process that causes bacterial wilt. We show that the activity of the enzyme is maximal during exponential growth in vitro and this growth-phase regulation occurs at the transcriptional level. Our studies also demonstrate that katE expression is transcriptionally activated by HrpG, a central regulator of R. solanacearum induced upon contact with the plant cells. In addition, we reveal that even though both KatE and KatG catalase activities are induced upon hydrogen peroxide treatment, KatE has a major effect on bacterial survival under oxidative stress conditions and especially in the adaptive response of R. solanacearum to this oxidant. The katE mutant strain also exhibited differences in the structural characteristics of the biofilms developed on an abiotic surface in comparison to wild-type cells, but not in the overall amount of biofilm production. The role of catalase KatE during the interaction with its host plant tomato is also studied, revealing that disruption of this gene has no effect on R. solanacearum virulence or bacterial growth in leave tissues, which suggests a minor role for this catalase in bacterial fitness in planta. Our work provides the first characterization of the R. solanacearum catalases and identifies KatE as a bona fide monofunctional catalase with an important role in bacterial protection against oxidative stress.

[Cardiac adverse effects of domperidone in adult patients: a systematic review]. / Efectos adversos cardíacos de la domperidona en pacientes adultos: revisión sistemática.

BACKGROUND: Domperidone is widely prescribed in patients with gastrointestinal disorders but some cardiac adverse effects have been recently reported. AIM: To evaluate the risk of QT prolongation, ventricular arrhythmias and sudden cardiac death associated with the use of oral domperidone in adults without cancer. MATERIAL AND METHODS: Systematic searches in MEDLINE, LILACS, SciELO, the Cochrane Library and regulatory agencies websites were performed, followed by a manual search of cited references. The search strategy consisted of combining free and indexed text words without any date or language restriction. RESULTS: Three case-control studies met the inclusion criteria; none of them evaluated QT interval prolongation. With low risk of bias, each study quantified the risk of ventricular arrhythmia or sudden cardiac death (VA/SCD). The odds ratios for these events in these studies were 4.7 (95% confidence interval (CI): 1.4-16), 1.59 (95% CI: 1.28-1.98) and 11.02 (95% CI: 2.02-62.3) respectively. A significantly increased risk was observed in patients older than 60 years of age or receiving doses > 30 mg/day. CONCLUSIONS: Heterogeneity between selected studies did not allow the computation of a summary measure. However, evidence was found that an increased risk of VA/SCD is associated with the use of oral domperidone in adults.

Efectos adversos cardíacos de la domperidona en pacientes adultos: revisión sistemática / Cardiac adverse effects of domperidone in adult patients: a systematic review

Background: Domperidone is widely prescribed in patients with gastrointestinal disorders but some cardiac adverse effects have been recently reported. Aim: To evaluate the risk of QT prolongation, ventricular arrhythmias and sudden cardiac death associated with the use of oral domperidone in adults without cancer. Material and Methods: Systematic searches in MEDLINE, LILACS, SciELO, the Cochrane Library and regulatory agencies websites were performed, followed by a manual search of cited references. The search strategy consisted of combining free and indexed text words without any date or language restriction. Results: Three case-control studies met the inclusion criteria; none of them evaluated QT interval prolongation. With low risk of bias, each study quantified the risk of ventricular arrhythmia or sudden cardiac death (VA/SCD). The odds ratios for these events in these studies were 4.7 (95% confidence interval (CI): 1.4-16), 1.59 (95% CI: 1.28-1.98) and 11.02 (95% CI: 2.02-62.3) respectively. A significantly increased risk was observed in patients older than 60 years of age or receiving doses > 30 mg/day. Conclusions: Heterogeneity between selected studies did not allow the computation of a summary measure. However, evidence was found that an increased risk of VA/SCD is associated with the use of oral domperidone in adults.

[Proarrhythmic effects of domperidone in infants: a systematic review]. / Revisión Sistemática de la evidencia de efectos proarrítmicos de domperidona en infantes.

AIMS: To assess the association of the use of domperidone in infants with QTc interval prolongation and proarrhythmic events. METHODS: A systematic search of the scientific literature was conducted without any date or language restriction. The electronic database MEDLINE and the sources LILACS, ScIELO and Cochrane library were consulted. RESULTS: From the twelve identified studies, eight were excluded because they did not meet the inclusion criteria. One case report and three pilot studies were selected. Rocha et al (2005) reported the case of an infant (age 3 months) with QTc interval = 463 ms after being treated during one month with 1.8 mg/kg/day of oral domperidone. Djeddi et al (2008) administered an average dose of 1.3 mg/kg/day to 31 neonates; QTc interval prolongation > 30 ms was observed in nine neonates. Hegar et al (2009) studied 10 infants (mean age 5.6 months) who received 0.8 mg/ kg/day of oral domperidone; QTc interval prolongation was not observed. Günlemez et al (2010) enrolled 40 premature infants who were administered 1 mg/kg/day of oral domperidone; the QTc interval increased to above 450 ms in two infants. CONCLUSIONS: Although evidence that orally administrated domperidone in infants produces prolongation of QTc interval was found, further studies are needed in order to quantify the risk associated with the drug in that population. We suggest that heath professionals should conduct ECGs to infants treated with domperidone and inform the pharmacovigilance system the occurrence of any case of adverse event.

Objetivo: Determinar si existe evidencia de prolongación del intervalo QTc y efectos proarrítmicos asociados al uso de domperidona oral en infantes. Método: Se realizó una revisión sistemática de la literatura científica consultando la base de datos electrónica MEDLINE y las fuentes LILACS, ScIELO y Biblioteca Cochrane a través de la Biblioteca Virtual de Salud, sin límite de fecha ni de idioma. Resultados: De los estudios identificados se excluyeron ocho por no cumplir con los criterios de inclusión, quedando seleccionados un reporte de caso y tres estudios pilotos. Rocha et al (2005) reportan el caso de un niño de 3 meses con intervalo QTc=463 mseg tras un mes de tratamiento con 1,8 mg/kg/día de domperidona oral. Djeddi et al (2008) administraron una dosis promedio de 1,3 mg/kg/día a 31 neonatos, observando prolongación del intervalo QTc>30 mseg en nueve. Hegar et al (2009) estudiaron a 10 niños con edad media de 5,6 meses tratados con 0,8 mg/kg/día y no observaron prolongación del intervalo QTc. Gunlemez et al (2010) incluyeron en su estudio a 40 infantes prematuros a quienes administraron 1 mg/kg/día de domperidona oral, en dos de ellos el intervalo QTc aumentó por encima de 450 mseg. Conclusiones: Aunque se encontró evidencia de prolongación del intervalo QTc en infantes tratados con domperidona oral, se necesitan más estudios para cuantificar el riesgo asociado a la droga en esta población. Se sugiere a los profesionales de la salud realizar un monitoreo electrocardiográfico de los infantes tratados con domperidona e informar al sistema de farmacovigilancia los casos de ocurrencia de eventos adversos.

Revisión Sistemática de la evidencia de efectos proarrítmicos de domperidona en infantes / Proarrhythmic effects of domperidone in infants: a systematic review

Objetivo: Determinar si existe evidencia de prolongación del intervalo QTc y efectos proarrítmicos asociados al uso de domperidonaoral en infantes. Método: Se realizó una revisión sistemática de la literatura científica consultando la base de datos electrónica MEDLINEy las fuentes LILACS, ScIELO y Biblioteca Cochrane a través de la Biblioteca Virtual de Salud, sin límite de fecha ni de idioma. Resultados: De los estudios identificados se excluyeron ocho por no cumplir con los criterios de inclusión, quedando seleccionados un reporte de caso y tres estudios pilotos. Rocha etal (2005) reportan el caso de un niño de 3 meses con intervalo QTc=463 mseg tras un mes de tratamiento con 1,8 mg/kg/díade domperidona oral. Djeddi et al (2008) administraron unadosis promedio de 1,3 mg/kg/día a 31 neonatos, observando prolongación del intervalo QTc>30 mseg en nueve. Hegar et al (2009) estudiaron a 10 niños con edad media de 5,6 meses tratados con 0,8 mg/kg/día y no observaron prolongación del intervalo QTc. Gunlemez et al (2010) incluyeron en su estudio a 40 infantes prematuros a quienes administraron 1 mg/kg/día de domperidona oral, en dos de ellos el intervalo QTc aumentó por encima de 450 mseg. Conclusiones: Aunque se encontró evidencia de prolongación del intervalo QTc en infantes tratados con domperidona oral, se necesitan más estudios para cuantificar el riesgo asociado a la droga en esta población. Se sugiere a los profesionales de la salud realizar un monitoreo electrocardiográfico de los infantes tratados con domperidona e informar al sistema de farmacovigilancia los casos de ocurrencia de eventos adversos

Aims: To assess the association of the use of domperidone in infants with QTc interval prolongation and proarrhythmic events. Methods: A systematic search of the scientific literature was conducted without any date or language restriction. The electronic database MEDLINE and the sources LILACS, ScIELO and Cochrane library were consulted. Results: From the twelve identified studies, eight were excluded because they did not meet the inclusion criteria. One case report and three pilot studies were selected. Rocha et al (2005) reported the case of an infant (age 3 months) with QTc interval = 463ms after being treated during one month with 1.8 mg/kg/day of oral domperidone. Djeddi et al (2008) administered an average dose of 1.3 mg/kg/day to 31 neonates; QTc interval prolongation > 30 ms was observed in nine neonates. Hegar et al (2009) studied 10 infants (mean age 5.6 months) who received 0.8 mg/ kg/day of oral domperidone; QTc interval prolongation was not observed. Günlemez et al (2010) enrolled 40 premature infants who were administered 1 mg/kg/day of oral domperidone; the QTc interval increased to above 450 ms in two infants. Conclusions: Although evidence that orally administrated domperidone in infants produces prolongation of QTc interval was found, further studies are needed in order to quantify the risk associated with the drug in that population. We suggest that heath professionals should conduct ECGs to infants treated with domperidone and inform the pharmacovigilance system the occurrence of any case of adverse event