Comparative Analysis of Novel Lytic Phages for Biological Control of Phytopathogenic Xanthomonas spp.

Xanthomonas is an important genus of plant-pathogenic bacteria that affects agronomic and economically important crops, causing serious economic losses. In fact, several Xanthomonas species are considered regulated quarantine pests. Due to the lack of effective control measures to treat plant-pathogenic bacteria, innovative control tools are needed to carry out integrated disease management. In this regard, bacteriophages (phages), viruses of bacteria, constitute a promising biocontrol tool. In this work, we report the isolation and characterization of 11 novel Xanthomonas arboricola pv. juglandis phages belonging to different families and genera of the class Caudoviricetes. Infectivity matrix in more than 60 isolates of different xanthomonads and other phytopathogenic bacteria suggests that these phages are specific to the Xanthomonas genus, with different host ranges depending on the isolates tested. Interestingly, some of these phages showed relevant features to be used as biocontrol tools to combat pathogenic Xanthomonas spp. as important as X. oryzae or X. citri. IMPORTANCE Phytopathogenic bacteria represent serious losses worldwide. The lack of current treatments has focused the spotlight on phages, viruses of bacteria, as very promising biocontrol tools. Phages are very specific and can help to control bacterial infections in crops, as is the case of xanthomonads-associated diseases. The discovery of new environmental phages with lytic capacity that can help to combat these pathogens is of special relevance, and it is necessary to implement phage isolation and characterization techniques to determine their host range and their genomic properties. The establishment of phage collections worldwide will allow their use as preventive, diagnostic, or therapeutic tools. Although there is still a long way to go, this work is a step forward in the implementation of new ecofriendly techniques to combat key pathogens in the field.

Evidence that Xylella fastidiosa is the Causal Agent of Almond Leaf Scorch Disease in Alicante, Mainland Spain (Iberian Peninsula).

In 2017, Xylella fastidiosa, a quarantine plant-pathogenic bacterium in Europe, was detected in almond trees associated with leaf scorch symptoms in Alicante, a Mediterranean area in southeastern mainland Spain. The bacterium was detected by serological and molecular techniques, isolated in axenic culture from diseased almond trees, and identified as X. fastidiosa subsp. multiplex sequence type (ST) 6. Inoculation experiments on almond plants in greenhouse trials with a characterized strain of X. fastidiosa subsp. multiplex ST6 isolated in the outbreak area have proved that it was able to multiply and systemically colonize inoculated plants. Disease symptoms characteristic of leaf scorch like those observed in the field were observed in the inoculated almond trees after 1 year. Furthermore, the pathogen was reisolated and identified by molecular tests. With the fulfillment of Koch's postulates, we have demonstrated that X. fastidiosa is the causal agent of the almond leaf scorch disease in the Alicante outbreak.

Primer consenso venezolanode enfermedad por reflujo gastroesofágico / Venezuelan consensus on gastroesophageal reflux diseases

El Consenso Venezolano de Enfermedad por Reflujo Gastroesófágico (ERGE) se realizó con el objeto de proveer guías para mejorar la identificación, el diagnóstico y el tratamiento de este trastorno en el país. Los coordinadores establecieron las líneas de consenso, basado en una revisión sistemática de la literatura médica de los últimos 15 años a partir de 1995. Participaron 55 miembros con el aval de sus respectivas cátedras y sociedades locales de gastroenterología. Éstos revisaron y presentaron los temas con sus niveles de evidencia y grados de recomendación para discutirlos y votarlos en una reunión plenaria. Tras un informe final de los miembros, los coordinadores prepararon las declaraciones finales. El consenso concluyó que la enfermedad por reflujo gastroesofágico tiene una prevalencia estimada del 11,54% en Venezuela, a predominio del sexo femenino (Grado B). El diagnóstico es fundamentalmente clínico, basado en la presencia de síntomas típicos y/o atípicos, e incluso síntomas de alarma que sugieren alguna complicación (Grado B). La endoscopia es importante en la investigación de la presencia de esofagitis de reflujo y laringitis de reflujo (Grado B). Las otras pruebas diagnósticas como lo son la pHmetría esofágica de 24 horas con o sin impedancia intraluminal multicanal son importantes en los pacientes que no tienen esofagitis, tienen síntomas atípicos o cuando hay falla en la respuesta al tratamiento médico (Grado B). La radiología, manometría esofágica y el ultrasonido endoscópico no están indicados en el diagnóstico de la ERGE (Grado B). El objetivo del tratamiento es reducir la exposición ácida en el esófago y con esto: aliviar los síntomas, cicatrizar las lesiones en la mucosa esofágica, prevenir la recurrencia y las complicaciones. Los inhibidores de bomba de protones deberían ser la primera opción en el tratamiento en el síndrome de ERGE y en la esofagitis por reflujo tanto en la fase aguda como durante el mantenimiento...

The Venezuelan Gastroesophageal Reflux Disease (GERD) Consensus was carried out in order to provide guidelines to improve the identification, diagnosis and treatment of this illness in Venezuela.  The coordinators established the consensuslines, based on a systematic revision of the medical literature of the last 15 years starting from 1995. 55 physicians participated with the support of their respective medical schools and local societies. They revised and presented the topics with their respective evidence levels and recommendation grades to discuss and vote them in a plenary meeting. After a final report of the members, the coordinators prepared the definitive declarations. The consensus concluded that GERD prevalence in Venezuela is 11,54%, higher in women than men (Grade B). The diagnosis is mainly clinical, based on the presence of typical and/or atypical symptoms and alarm symptoms that may suggest the presence of complications (Grade B). Endoscopy is important when reflux esophagitis and laryngitis are present (Grade B). Other diagnostic tests as ambulatory 24 hours pH monitoring with or without multichannel intraluminal impedance are important in patients without esophagitis, with atypical symptoms or when there is flaw in the answer to the medical treatment (Grade B). Radiology, esophageal manometry and endoscopic ultrasonography are not indicated in the diagnosis of GERD (Grade B). The objective of the treatment is to reduce the presence of acid in the esophagus and consequently: alleviate the symptoms and heal lesions in the esophagus mucosa to prevent recurrence and complications. Proton pump inhibitors should be the first option drug in the treatment of GERD syndrome andin esophagitis during the acute and the maintenance phase using standard or half dose (Grade A). So far, pokinetics are drugs with a limited use in GERD patients; they stimulate the esophagus/gastric motility...