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IntroductionBacteriophages have been shown to penetrate biofilms and replicate if they find suitable host cells. Therefore, these viruses appear to be a good option to tackle the biofilm problem and complement or even substitute more conventional antimicrobials. However, in order to successfully remove biofilms, in particular mature biofilms, phages may need to be administered along with other compounds. Phage-derived proteins, such as endolysins or depolymerases, offer a safer alternative to other compounds in the era of antibiotic resistance.MethodsThis study examined the interactions between phage Kayvirus rodi with a polysaccharide depolymerase (Dpo7) from another phage (Rockefellervirus IPLA7) against biofilms formed by different Staphylococcus aureus strains, as determined by crystal violet staining, viable cell counts and microscopy analysis.Results and discussionOur results demonstrated that there was synergy between the two antimicrobials, with a more significant decreased in biomass and viable cell number with the combination treatment compared to the phage and enzyme alone. This observation was confirmed by microscopy analysis, which also showed that polysaccharide depolymerase treatment reduced, but did not eliminate extracellular matrix polysaccharides. Activity assays on mutant strains did not identify teichoic acids or PNAG/PIA as the exclusive target of Dpo7, suggesting that may be both are degraded by this enzyme. Phage adsorption to S. aureus cells was not significantly altered by incubation with Dpo7, indicating that the mechanism of the observed synergistic interaction is likely through loosening of the biofilm structure. This would allow easier access of the phage particles to their host cells and facilitate infection progression within the bacterial population.

Summary: Flaviviruses such as dengue virus (DENV), Zika virus (ZIKV), and yellow fever virus (YFV) are spread by mosquitoes and cause human disease and mortality in tropical areas. In contrast, Powassan virus (POWV), which causes severe neurologic illness, is a flavivirus transmitted by ticks in temperate regions of the Northern hemisphere. We find serologic neutralizing activity against POWV in individuals living in Mexico and Brazil. Monoclonal antibodies P002 and P003, which were derived from a resident of Mexico (where POWV is not reported), neutralize POWV lineage I by recognizing an epitope on the virus envelope domain III (EDIII) that is shared with a broad range of tick- and mosquito-borne flaviviruses. Our findings raise the possibility that POWV, or a flavivirus closely related to it, infects humans in the tropics.

BackgroundInfections by the pathogen Staphylococcus aureus currently represent one of the most serious threats to human health worldwide, especially due to the production of enterotoxins and the ability to form biofilms. These structures and the acquisition of antibiotic resistance limit the action of antibiotics and disinfectants used to combat this microorganism in the industry and the clinic.MethodsThis work reports a comparative phenotypic and genotypic study of 18 S. aureus strains from different origins: clinical samples, milk from mastitic cows and food industry surfaces, most of which were isolated in Northern Spain.ResultsGenetically, the strains were very diverse but, in most cases, a closer proximity was observed for those from the same source. Notably, the average number of virulence genes was not significantly different in strains from the food sector. Of the 18 strains, 10 coded for at least one enterotoxin, and four of them carried 6 or 7 enterotoxin genes. The latter were all veterinary or clinical isolates. Most strains carried prophages, plasmids and/or pathogenicity islands. Regarding antibiotic resistance, although phenotypically all strains showed resistance to at least one antibiotic, resistance genes were only identified in 44.5% of strains, being mastitis isolates those with the lowest prevalence. Virulence-related phenotypic properties such as haemolytic activity, staphyloxanthin production, biofilm-forming capacity and spreading ability were widely distributed amongst the isolates.ConclusionsOur results indicate that production of virulence factors, antibiotic resistance and biofilm formation can be found in S. aureus isolates from diverse environments, including the food industry, although some of these traits are more prevalent in strains isolated from infections in cows or humans. This emphasizes on the importance of monitoring the spread of these determinants not only in samples from the clinical environment, but also along the food chain, a strategy that falls under the prism of a one-health approach.

Environmental cues sometimes have a direct impact on phage particle stability, as well as bacterial physiology and metabolism, having a profound effect on phage infection outcome. Here, we explore the impact of temperature on the interplay between phage Kayvirus rodi (phiIPLA-RODI) and its host, Staphylococcus aureus. Our results show that phiIPLA-RODI is a more effective predator at room (25 °C) compared to body temperature (37 °C) against planktonic cultures of several strains with varying degrees of phage susceptibility. This result differs from most known examples of temperature-dependent phage infection, in which optimum infection is correlated with the host growth rate. Further characterization of this phenomenon was carried out with strains IPLA15 and IPLA16, whose respective MICs were 7 log units and a 1-log unit higher at 37 °C than at 25 °C. Our results demonstrated that the phage also had a greater impact at room temperature during biofilm development and for the treatment of preformed biofilms. There was no difference in phage adsorption between the two temperatures for strain IPLA16. Conversely, adsorption of phiIPLA-RODI to IPLA15 was reduced at 37 °C compared to 25 °C. Moreover, confocal microscopy analysis indicated that the biofilm matrix of both strains has a greater content of PIA/PNAG at 37 °C than at 25 °C. Regarding infection parameters, we observed longer duration of the lytic cycle at 25 °C for both strains, and infection of IPLA15 by phiIPLA-RODI resulted in a smaller burst size at 37 °C than at 25 °C. Finally, we also found that the rate of phage resistant mutant selection was higher at 37 °C for both strains. Altogether, this information highlights the impact that bacterial responses to environmental factors have on phage-host interactions. Moreover, phage phiIPLA-RODI appears to be a highly effective candidate for biofilm disinfection at room temperature, while its efficacy in biofilm-related infections will require combination with other antimicrobials.

El año 2020 ha transformado la vida de la mayoría de los habitantes del planeta. Hace un año hubiera sido inimaginable pensar que una situación como la actual pudiera ser real y no fruto de una película perteneciente al género de catástrofes. Con este artículo queremos dejar constancia de la repercusión emocional e intelectual que supuso la coincidencia de la pandemia con el desarrollo de una asignatura optativa transversal para los grados de Ciencias de la Salud centrada en el uso del cine y la literatura como recursos docentes. La coincidencia temporal del inicio del confinamiento al que se vio sometida toda la población española, con el desarrollo del módulo de catástrofes y, más concretamente con el tema de las epidemias, revistió el progreso del resto de la asignatura de un ambiente especial que tal vez no volvamos a vivir, al menos con las mismas características.

Despite occurring at the microscopic scale, the armed race between phages and their bacterial hosts involves multiple mechanisms, some of which are just starting to be understood. On the one hand, bacteria have evolved strategies that can stop the viral infection at different stages (adsorption, DNA injection and replication, biosynthesis and assembly of the viral progeny and/or release of the newly formed virions); on the other, phages have gradually evolved counterattack strategies that allow them to continue infecting their prey. This co-evolutionary process has played a major role in the development of microbial populations in both natural and man-made environments. Notably, understanding the parameters of this microscopic war will be paramount to fully benefit from the application of phage therapy against dangerous, antibiotic-resistant human pathogens. This review gathers the current knowledge regarding the mechanisms of phage resistance in the Staphylococcus genus, which includes Staphylococcus aureus, one of the most concerning microorganisms in terms of antibiotic resistance acquisition. Some of these strategies involve permanent changes to the bacterial cell via mutations, while others are transient, adaptive changes whose expression depends on certain environmental cues or the growth phase. Finally, we discuss the most plausible strategies to limit the impact of phage resistance on therapy, with a special emphasis on the importance of a rational design of phage cocktails in order to thwart therapeutic failure.

Cellular antiviral programs encode molecules capable of targeting multiple steps in the virus lifecycle. Zinc-finger antiviral protein (ZAP) is a central and general regulator of antiviral activity that targets pathogen mRNA stability and translation. ZAP is diffusely cytoplasmic, but upon infection ZAP is targeted to particular cytoplasmic structures, termed stress granules (SGs). However, it remains unclear if ZAP's antiviral activity correlates with SG localization, and what molecular cues are required to induce this localization event. Here, we use Sindbis virus (SINV) as a model infection and find that ZAP's localization to SGs can be transient. Sometimes no apparent viral infection follows ZAP SG localization but ZAP SG localization always precedes accumulation of SINV non-structural protein, suggesting virus replication processes trigger SG formation and ZAP recruitment. Data from single-molecule RNA FISH corroborates this finding as the majority of cells with ZAP localization in SGs contain low levels of viral RNA. Furthermore, ZAP recruitment to SGs occurred in ZAP-expressing cells when co-cultured with cells replicating full-length SINV, but not when co-cultured with cells replicating a SINV replicon. ZAP recruitment to SGs is functionally important as a panel of alanine ZAP mutants indicate that the anti-SINV activity is correlated with ZAP's ability to localize to SGs. As ZAP is a central component of the cellular antiviral programs, these data provide further evidence that SGs are an important cytoplasmic antiviral hub. These findings provide insight into how antiviral components are regulated upon virus infection to inhibit virus spread.

Introduction. It has been established in the literature that a proportion of patients who undergo antireflux surgery present shorthening of the esophagus. If this is not recognized, it may be associated with anatomical failure of the surgery and symptomatic recurrence. The incidence of this condition is unknown in our environment. Methods. Retrospective, descriptive study in patients with hiatal hernia (HH) and gastroesophageal reflux disease (GERD) undergoing laparoscopic antireflux surgery in a high complexity institution over a three-year period. Demographic, clinical, operative, and postoperative characteristics were described. Cases of short esophagus and the surgical technique used to correct it were identified. Results. One hundred and ten laparoscopic antireflux procedures were performed, of which 56 (50.9%) were HH repair plus fundoplication and 54 (49.1%) were giant HH repair plus fundoplication and/or decompressive gastrostomy. Seven (6.3%) patients had a short esophagus and required esophageal lengthening by Collis-type gastroplasty. At preoperative evaluation, five (71%) reported sympotms lasting more than 4 years, five (71%) had dysphagia, six (85.7%) had giant HH, and six (85.7%) had some degree of esophagitis. The average hospital stay was 4.4 days. There was one major complication and no mortality. All achieved adequate postoperative radiological and symptomatic control. Conclusions. Short esophagus is a real condition, which should be anticipated especially in patients with giant HH and chronic GERD. Laparoscopic Collis esophagogastroplasty is a reasonable treatment alternative. [ABSTRACT FROM AUTHOR]

La definición y análisis de los requisitos de software son factores claves para el éxito final de los proyectos de software en particular para una adecuada calidad de software. La priorización de requisitos de software, es un proceso de toma de decisiones, que en ocasiones se torna complejo, debido a que en este proceso se determinan las funcionalidades necesarias a incluir en el producto a desarrollar y se relaciona con la calidad del software. Esta calidad se mide por la capacidad que posee el software para satisfacer las necesidades de los clientes y usuarios finales. La satisfacción de necesidades implica una correcta ingeniería que incluye requisitos especialmente de priorización. Priorizar los requisitos de software es un proceso que no está concebido suficientemente en cuanto a la flexibilidad y adaptabilidad a los contextos específicos de las organizaciones. La priorización de requisitos contribuye a la identificación de los conjuntos que son críticos para el éxito del proyecto de software, conjuntos que se ubican en las primeras iteraciones, y el otro resto de conjuntos que son críticos para el éxito del proyecto son considerados triviales y se ejecutan más tardíos. Este proceso permite ordenar el conjunto total de requisitos, lo que permite la formación de subconjuntos y su asignación de iteraciones. En el presente trabajo, se propone el uso de la priorización de requisitos de software, que hace uso de los operadores de agregación de forma jerárquica, para una adecuada calidad del software.