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"Silva, Rodrigo"
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Occurrence and characterization of methicillin-resistant Staphylococcus spp. in diseased dogs in Brazil
Staphylococcus pseudintermedius is a major commensal bacterium of the skin and mucosae of dogs and an opportunistic agent responsible for several clinical infections, such as pyoderma, otitis, and surgical wound infections. The emergence of methicillin-resistant S . pseudintermedius (MRSP) has become a problem of great concern in veterinary and human medicine because it is multidrug resistant (MDR) and can also infect humans. This study aimed to identify the occurrence of Staphylococcus spp. in infected patients and investigate the antimicrobial resistance profiles and molecular structure of MRSP isolates. Samples were obtained from two different veterinary clinics; suggestive colonies were submitted to matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry and confirmed at the species level by polymerase chain reaction (PCR). Sequencing of the 16S rRNA and rpoB genes were used in selected samples that were not identified by MALDI-ToF and by the species-specific PCR. Antimicrobial susceptibility and PCR detection of mecA were performed. MRSP isolates were subjected to multilocus sequence typing. Of all the clinical staphylococci (n = 131), 98 (74.8%) were identified as S . pseudintermedius . Multidrug resistance (resistance to ≥3 classes of antimicrobials) was observed in 63.2% of S . pseudintermedius isolates, and 24.5% of S . pseudintermedius isolates were methicillin-resistant. Half of the MRSP isolates were isolated from surgical site infections. Among the ten sequence types (ST) identified, nine were novel. ST71 was the most prevalent and associated with resistance to fluoroquinolones. Prior antimicrobial therapy, hospitalization, and surgical site infections seemed to be risk factors for MRSP acquisition. The present study showed a high rate of MDR staphylococci in infected dogs. MRSP was isolated from different clinical conditions, mainly surgical site infections. Additionally, this is the first study to extensively investigate the population structure of MRSP in Brazil, which revealed the dispersion of CC71 and nine novel ST. These findings raise concerns for both animal and human health due to the zoonotic potential of this species and limited therapeutic options available for MRSP infections.
Journal Article
Fecal shedding of Salmonella spp., Clostridium perfringens, and Clostridioides difficile in dogs fed raw meat-based diets in Brazil and their owners’ motivation
The present study aimed to explore the motivations of Brazilian dog owners and their knowledge about the risks related to raw meat-based diets (RMBD) as well as to evaluate important enteropathogens such as Salmonella spp., C. perfringens, and C. difficile, in feces of dogs fed different diets. The majority of the pet owners (69.3%) reported to have chosen this diet for their dogs, considering it to be more \"natural\". A large number of owners declared that RMBD do not pose health risks for their animals (87.9%) or humans (98.8%), even though almost one third of the respondents (34.8%) declared having at least one individual at high risk of infection in contact with RMBD-fed dogs. Stool samples from 46 RMBD-fed dogs and 192 dogs fed commercial dry feed were collected. The present study revealed that dogs fed raw meat diets were almost 30 times more likely to be positive for Salmonella spp. than dogs on a conventional diet. Some of the serovars detected were commonly associated with human salmonellosis, such as S. Typhimurium and S. Saintpaul, and were multidrug resistant. RMBD-fed dogs were more likely to be positive for C. perfringens type A (p = 0.008) and one C. perfringens type F was isolated from these animals. Two toxigenic strains (4.3%) of C. difficile were isolated only from raw meat-fed dogs, all of which were under antibiotic therapy. These toxigenic C. difficile isolates were classified as RT106/ST54 and RT600/ST149, previously associated with infection in dogs and humans. The present work revealed that the owners have a tendency to ignore or are unaware of the risks associated with raw meat diets for dogs. Also, the higher fecal shedding of important enteropathogens in dogs fed RMBD suggests that this diet poses a risk for the animals and the people in contact with them.
Journal Article
Prevalence of post-traumatic stress disorder symptoms in adult critical care survivors: a systematic review and meta-analysis
Background
As more patients are surviving intensive care, mental health concerns in survivors have become a research priority. Among these, post-traumatic stress disorder (PTSD) can have an important impact on the quality of life of critical care survivors. However, data on its burden are conflicting. Therefore, this systematic review and meta-analysis aimed to evaluate the prevalence of PTSD symptoms in adult critical care patients after intensive care unit (ICU) discharge.
Methods
We searched MEDLINE, EMBASE, LILACS, Web of Science, PsycNET, and Scopus databases from inception to September 2018. We included observational studies assessing the prevalence of PTSD symptoms in adult critical care survivors. Two reviewers independently screened studies and extracted data. Studies were meta-analyzed using a random-effects model to estimate PTSD symptom prevalence at different time points, also estimating confidence and prediction intervals. Subgroup and meta-regression analyses were performed to explore heterogeneity. Risk of bias was assessed using the Joanna Briggs Institute tool and the GRADE approach.
Results
Of 13,267 studies retrieved, 48 were included in this review. Overall prevalence of PTSD symptoms was 19.83% (95% confidence interval [CI], 16.72–23.13;
I
2
= 90%, low quality of evidence). Prevalence varied widely across studies, with a wide range of expected prevalence (from 3.70 to 43.73% in 95% of settings). Point prevalence estimates were 15.93% (95% CI, 11.15–21.35;
I
2
= 90%; 17 studies), 16.80% (95% CI, 13.74–20.09;
I
2
= 66%; 13 studies), 18.96% (95% CI, 14.28–24.12;
I
2
= 92%; 13 studies), and 20.21% (95% CI, 13.79–27.44;
I
2
= 58%; 7 studies) at 3, 6, 12, and > 12 months after discharge, respectively.
Conclusion
PTSD symptoms may affect 1 in every 5 adult critical care survivors, with a high expected prevalence 12 months after discharge. ICU survivors should be screened for PTSD symptoms and cared for accordingly, given the potential negative impact of PTSD on quality of life. In addition, action should be taken to further explore the causal relationship between ICU stay and PTSD, as well as to propose early measures to prevent PTSD in this population.
Trial registration
PROSPERO,
CRD42017075124
, Registered 6 December 2017.
Journal Article
On the Location of Fog Nodes in Fog-Cloud Infrastructures
In the fog computing paradigm, fog nodes are placed on the network edge to meet end-user demands with low latency, providing the possibility of new applications. Although the role of the cloud remains unchanged, a new network infrastructure for fog nodes must be created. The design of such an infrastructure must consider user mobility, which causes variations in workload demand over time in different regions. Properly deciding on the location of fog nodes is important to reduce the costs associated with their deployment and maintenance. To meet these demands, this paper discusses the problem of locating fog nodes and proposes a solution which considers time-varying demands, with two classes of workload in terms of latency. The solution was modeled as a mixed-integer linear programming formulation with multiple criteria. An evaluation with real data showed that an improvement in end-user service can be obtained in conjunction with the minimization of the costs by deploying fewer servers in the infrastructure. Furthermore, results show that costs can be further reduced if a limited blocking of requests is tolerated.
Journal Article
Fatigue and resilience in Master’s and PhD students in the Covid-19 pandemic in Brazil: A cross-sectional study
The aim of this study was to analyze levels of fatigue and resilience of Brazilian graduate students during the COVID-19 pandemic and to determine whether there is an association between fatigue and resilience and sociodemographic and academic factors. Data were analyzed using descriptive and inferential statistics, and it was discovered that the variables associated with higher levels of resilience were age; having children; being retired; receiving income above five minimum wages; having had greater problems in other phases of the research schedule; coming from private universities; being from the north of Brazil; studying the area of Health; and having their research schedule unaffected during the pandemic. On the other hand, lack of resilience was associated with not having children; being less well-off financially; being younger; being a woman; studying in a public university; and having to postpone part of the research during the pandemic. The conclusion of the study indicated the need for graduate programs to design strategies to deal with fatigue and promote resilience in Master’s and PhD students.
Journal Article
Dissolution rate and agronomic effectiveness of struvite fertilizers — effect of soil pH, granulation and base excess
Aims Struvite (MgNH₄PO₄.6H₂O) recovered from wastewater can be used as fertilizer. The agronomic effectiveness of struvite has mostly been evaluated using ground fertilizer mixed through soil. However, fertilizers are most commonly applied in granular form in the field. In this study, we assessed the dissolution and effectiveness of different struvites when applied in granular or powdered form. Methods Phosphorus (P) diffusion in soil, determined using a visualization technique and chemical analyses, and P uptake by 6-week old wheat was compared for soluble fertilizer (monoammonium phosphate, MAP), a commercial struvite and three synthesized struvites with different excess MgO, in both granular and ground form. Results Ground struvite mixed through soil quickly dissolved and its agronomic effectiveness was similar to that of MAP. For pure granular struvite, the granule dissolution rate ranged from circa 0.03 mg d⁻¹ in alkaline soil to 0.43 mg d⁻¹ in acidic soil. Excess base in the struvite fertilizer reduced its dissolution rate. The P uptake by wheat followed the order MAP >> struvite ≥ control (no P), with no significant difference between the control and the struvite treatment in alkaline soil. Conclusions Both fertilizer characteristics (particle size, excess base) and soil pH strongly affect the dissolution rate of struvite and hence its agronomic effectiveness.
Journal Article
AdequacyModel: An R package for probability distributions and general purpose optimization
Several lifetime distributions have played an important role to fit survival data. However, for some of these models, the computation of maximum likelihood estimators is quite difficult due to presence of flat regions in the search space, among other factors. Several well-known derivative-based optimization tools are unsuitable for obtaining such estimates. To circumvent this problem, we introduce the AdequacyModel computational library version 2.0.0 for the R statistical environment with two major contributions: a general optimization technique based on the Particle Swarm Optimization (PSO) method (with a minor modification of the original algorithm) and a set of statistical measures for assessment of the adequacy of the fitted model. This library is very useful for researchers in probability and statistics and has been cited in various papers in these areas. It serves as the basis for the Newdistns library (version 2.1) published in an impact journal in the area of computational statistics, see https://CRAN.R-project.org/package=Newdistns. It is also the basis of the Wrapped library (version 2.0), see https://CRAN.R-project.org/package=Wrapped. A third package making use of the AdequacyModel library can be found in https://CRAN.R-project.org/package=sglg. In addition, the proposed library has proved to be very useful for maximizing log-likelihood functions with complex search regions. The library provides a greater control of the optimization process by introducing a stop criterion based on a minimum number of iterations and the variance of a given proportion of optimal values. We emphasize that the new library can be used not only in statistics but in physics and mathematics as proved in several examples throughout the paper.
Journal Article
Rat models of lactose intolerance: sexually dimorphic comorbidities with neuropsychiatric disorders modulated by tryptophan hydroxylase and the dopaminergic system
Some studies indicate a sexually dimorphic effect, along with a potential predisposition to neuropsychiatric disorders in patients with lactose intolerance. This study proposed rat models of lactose intolerance, evaluating the manifestation of behaviors related to neuropsychiatric disorders, their incidence in each sex, and the underlying neurobiological processes. Rats were exposed to two lactose-rich diets: a solution containing 14% lactose and a commercial milk formula. Clinical signs were monitored. Behavioral tests for anxiety (light-dark box), social preference, and depression (forced swim test) were conducted. Brain dopamine levels and genetic and epigenetic (DNA methylation) expressions of tryptophan hydroxylase (
Tph
)1 in the intestine were also examined. Both diets were well consumed and led to impaired stool consistency. Males exhibited anxiolytic-like behavior, increased striatal dopamine levels, and decreased cortical dopamine levels after consuming the lactose solution. In contrast, females showed anxiogenic-like behavior and decreased cortical dopamine levels following the commercial formula. Male socialization was impaired by both diets. Furthermore, both diets reduced
Tph1
gene expression. In conclusion, this study introduced two rat models of lactose intolerance that revealed sexually dimorphic comorbidities with neuropsychiatric disorders, along with modulation of striatal and cortical dopaminergic systems and reduced genetic expression of the
Tph1
enzyme in the intestine.
Journal Article
Dynamics of Salmonella Dublin infection and antimicrobial resistance in a dairy herd endemic to salmonellosis
Salmonella Dublin is a serovar that causes severe infections and cattle. Despite the importance of this agent, research on achieving its elimination from dairy farms is limited, which complicates risk mitigation and control efforts. This study thus aimed to assess the prevalence of S . Dublin on a farm with a history of outbreaks, to understand the dynamics of the infection, characterize the antimicrobial resistance of the isolates, and evaluate their genetic similarity. Multiparous cows in the postpartum phase are nearly five times more likely to shed Salmonella sp. A total of 39 cases of fatal septicemic salmonellosis caused by S . Dublin were confirmed in calves aged 3–5 months. Antimicrobial susceptibility was evaluated in 45 strains of S . Dublin, with 48.9% of the isolates classified as multidrug resistant, including resistance to penicillin (48.9%), tetracyclines (42.2%), and fluoroquinolones (33.3%). Seven multidrug-resistant isolates were selected for genomic sequencing. Among the resistance determinants identified, a mutation in the gyrA gene, present in all sequenced isolates, was notable. Analyses of cgMLST and SNPs revealed that the isolates from healthy animals were closely related to those found in animals with confirmed cases of S . Dublin, confirming that the agent was circulating among healthy animals across various categories. A high similarity was also found between the isolates in this study and strains causing salmonellosis in humans in Brazil, thus reinforcing the zoonotic nature and possible epidemiological link between cattle, and the occurrence of this disease in humans.
Journal Article