This work studies the surface characteristics, antimicrobial activity, and aging effect of plasma-pretreated polyamide 6,6 (PA66) fabrics coated with silver nanoparticles (AgNPs), aiming to identify ...the optimum size of nanosilver exhibiting antibacterial properties suitable for the manufacture of hospital textiles. The release of bactericidal Ag+ ions from a 10, 20, 40, 60, and 100 nm AgNPs-coated PA66 surface was a function of the particles’ size, number, and aging. Plasma pretreatment promoted both ionic and covalent interactions between AgNPs and the formed oxygen species on the fibers, favoring the deposition of smaller-diameter AgNPs that consequently showed better immediate and durable antimicrobial effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. Surprisingly, after 30 days of aging, a comparable bacterial growth inhibition was achieved for all of the fibers treated with AgNPs <100 nm in size. The Ag+ in the coatings also favored the electrostatic stabilization of the plasma-induced functional groups on the PA66 surface, thereby retarding the aging process. At the same time, the size-related ratio (Ag+/Ag0) of the AgNPs between 40 and 60 nm allowed for the controlled release of Ag+ rather than bulk silver. Overall, the results suggest that instead of reducing the size of the AgNPs, which is associated with higher toxicity, similar long-term effects can be achieved with larger NPs (40–60 nm), even in lower concentrations. Because the antimicrobial efficiency of AgNPs larger than 30 nm is mainly ruled by the release of Ag+ over time and not by the size and number of the AgNPs, this parameter is crucial for the development of efficient antimicrobial coatings on plasma-treated surfaces and contributes to the safety and durability of clothing used in clinical settings.
This is a cost analysis study based on hospital admissions, conducted from the perspective of the Brazilian Unified Health System (SUS), carried out in a cohort of patients hospitalized at the ...University Hospital of Brasília (UHB) due to Severe Acute Respiratory Infections (SARI) caused by COVID-19, from April 1, 2020, to March 31, 2022. An approach based on macro-costing was used, considering the costs per patient identified in the Hospital Admission Authorizations (HAA). Were identified 1,015 HAA from 622 patients. The total cost of hospitalizations was R$ 2,875,867.18 for 2020 and 2021. Of this total, 86.41 % referred to hospital services and 13.59 % to professional services. The highest median cost per patient identified was for May 2020 (R$ 19,677.81 IQR 3,334.81–33,041.43), while the lowest was in January 2021 (R$ 1,698.50 IQR 1,602.70–2,224.11). The high cost of treating patients with COVID-19 resulted in a high economic burden of SARI due to COVID-19 for UHB and, consequently, for SUS.
The salivary glands (SG) of ixodid ticks play a pivotal role in blood feeding, producing both the cement and the saliva. The cement is an adhesive substance that helps the attachment of the tick to ...the host skin, while the saliva contains a rich mixture of antihemostatic, anti-inflammatory, and immunomodulatory substances that allow ticks to properly acquire the blood meal. The tick saliva is also a vehicle used by several pathogens to be transmitted to the vertebrate host, including various bacterial species from the genus
.
is a tick-borne obligate intracellular bacterium that causes the severe Rocky Mountain spotted fever. In Brazil, the dog yellow tick
is a vector of
. In the current study, the effects of an experimental infection with
on the global gene expression profile of
SG was determined by next-generation RNA sequencing. A total of 260 coding sequences (CDSs) were modulated by infection, among which 161 were upregulated and 99 were downregulated. Regarding CDSs in the immunity category, we highlight one sequence encoding one microplusin-like antimicrobial peptide (AMP) (Ambaur-69859). AMPs are important effectors of the arthropod immune system, which lack the adaptive response of the immune system of vertebrates. The expression of microplusin was confirmed to be significantly upregulated in the SG as well as in the midgut (MG) of infected
by a quantitative polymerase chain reaction preceded by reverse transcription. The knockdown of the microplusin expression by RNA interference caused a significant increase in the prevalence of infected ticks in relation to the control. In addition, a higher rickettsial load of one order of magnitude was recorded in both the MG and SG of ticks that received microplusin-specific dsRNA. No effect of microplusin knockdown was observed on the
transmission to rabbits. Moreover, no significant differences in tick engorgement and oviposition were recorded in ticks that received dsMicroplusin, demonstrating that microplusin knockdown has no effect on tick fitness. Further studies must be performed to determine the mechanism of action of this AMP against
.
In this review, we summarize existing knowledge of the ecology of sandy-beach nematodes, in relation to spatial distribution, food webs, pollution and climate change. We attempt to discuss spatial ...scale patterns (macro-, meso- and microscale) according to their degree of importance in structuring sandy-beach nematode assemblages. This review will provide a substantial background on current knowledge of sandy-beach nematodes, and can be used as a starting point to delineate further investigations in this field. Over decades, sandy beaches have been the scene of studies focusing on community and population ecology, both related to morphodynamic models. The combination of physical factors (e.g. grain size, tidal exposure) and biological interactions (e.g. trophic relationships) is responsible for the spatial distribution of nematodes. In other words, the physical factors are more important in structuring nematodes communities over large scale of distribution while biological interactions are largely important in finer-scale distributions. It has been accepted that biological interactions are assumed to be of minor importance because physical factors overshadow the biological interactions in sandy beach sediments; however, the most recent results from in-situ and ex-situ experimental investigations on behavior and biological factors on a microscale have shown promise for understanding the mechanisms underlying larger-scale patterns and processes. Besides nematodes are very promising organisms used to understand the effects of pollution and climate changes although these subjects are less studied in sandy beaches than distribution patterns.
We investigated if the differences in density and nematode communities of intertidal sediments from two Brazilian sheltered sandy beaches were related to environmental characteristics. The upper tide ...level (UTL) and the low tide level (LTL) of both beaches were surveyed in January (austral summer) and June 2001 (austral winter) during low-spring tides, by collecting samples of nematodes and sediments. Differences in density between beaches, tidal level and seasons, and nematode community structure were investigated. Sediments from both beaches were composed of medium to very coarse sand. The highest nematode densities were found at the UTL, and significant differences between beaches, tidal levels and months were found. A total of 54 genera were found and the genera composition on both sheltered beaches was similar to other exposed worldwide sandy beaches. The density and structure of the nematode community at both beaches clearly varied along the spatial and temporal scales. Gravel percentage was the most important variable explaining the spatial distribution of the nematodes, determining the four sub-communities; this suggests that the sediment characteristics influence the nematode community, rather than physical hydrodynamic forces. Temperature and salinity were suggested to be important variables affecting the temporal variation.
A new species of the genus Cephalanticoma is described for the Atlantic Ocean in the Potiguar Basin off the continental shelf of northeast Brazil. Cephalanticoma rugatusa sp. n. is characterized by ...bearing head capsule ending on the level of amphideal fovea, a tubular precloacal supplement and two rows of thin precloacal setae. Cephalanticoma rugatusa sp. n. differs from all other species of the genus by having a precloacal cuticular papilla in front of the cloaca and a cuticular transversal wrinkle which extends from the papilla elevation to the conical-cylindrical portion of the tail occupying both subventral regions. An emended diagnosis and a dichotomous key to species based on both genders are provided.
Anaplasma marginale is the causative agent of the severe bovine anaplasmosis. The tick Rhipicephalus microplus is one of the main vectors of A. marginale in tropical and subtropical regions of the ...world. After the tick bite, the bacterium invades and proliferates within the bovine erythrocytes leading to anemia, impairment of milk production and weight loss. In addition, infection can cause abortion and high mortality in areas of enzootic instability. Immunization with live and inactivated vaccines are employed to control acute bovine anaplasmosis. However, they do not prevent persistent infection. Consequently, infected animals, even if immunized, are still reservoirs of the bacterium and contribute to its dissemination. Antimicrobials are largely employed for the prophylaxis of bovine anaplasmosis. However, they are often used in sublethal doses which may select pre-existing resistant bacteria and induce genetic or phenotypic variations. Therefore, we propose a new standardized in vitro assay to evaluate the susceptibility of A. marginale strains to different antimicrobials. This tool will help health professionals to choose the more adequate treatment for each herd which will prevent the selection and spread of resistant strains. For that, we initially evaluated the antimicrobial susceptibility of two field isolates of A. marginale (Jaboticabal and Palmeira) infecting bovines. The least susceptible strain (Jaboticabal) was used for the standardization of an antimicrobial assay using a culture of Ixodes scapularis-derived tick cell line, ISE6. Results showed that enrofloxacin (ENRO) at 0.25, 1 or 4 μg/mL and oxytetracycline (OTC) at 4 or 16 μg/mL are the most efficient treatments, followed by OTC at 1 μg/mL and imidocarb dipropionate (IMD) at 1 or 4 μg/mL. In addition, this proposed tool has technical advantages compared to the previously established bovine erythrocyte culture. Thereby, it may be used to guide cattle farmers to the correct use of antimicrobials. The choice of the most suitable antimicrobial is essential to eliminate persistent infections, prevent the spread of resistant strains and help controlling of bovine anaplasmosis.
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•A. marginale strains infecting calves exhibit distinct susceptibility to antimicrobials.•Evaluation of A. marginale antimicrobial susceptibility using an in vitro assay with tick cell line.•Assessment of the efficacy of novel antimicrobial drugs by in vitro assay.
A monitoring program of pesticides was implemented in the “ZV1” vulnerable zone (Directive 91/676/EEC) in Portugal, in order to assess the impact of intensive horticulture practices on groundwater ...contamination. The monitoring network comprised 23 sampling points sampled every 3 months during a 2-year period. Forty-two pesticides belonging to varied chemical families, including current pesticides, persistent organic pollutants (POPs), and degradation products, were analyzed by solid-phase microextraction (SPME) and gas chromatography with electron-capture detection-thermoionic specific detection (GC-ECD-TSD) or mass spectrometry (GC-MS). Statistical treatment was performed by descriptive analysis followed by chemometric multivariate analysis. The latter included cluster analysis, linear discriminant analysis, and factor analysis. Twenty-two pesticides were quantitated, 20 pesticides were not detected, and metalaxyl, benalaxyl, quinalphos, pirimicarb, and prometryn were only qualitatively detected. The most frequently detected pesticides (% of samples analyzed) were lindane (53%), pendimethalin (49%), endosulfan sulfate (44%), and endosulfan (38%) while those that most frequently exceeded the 0.1 μg L-1 European Union (EU) limit were pendimethalin (13%), endosulfan (12%), endosulfan sulfate (11%), and atrazine (9%). 45% of the samples exceeded the EU limit for individual pesticides while 27% exceeded the limit set to the sum of pesticides (0.5 μg L-1). Principal component analysis revealed five principal components that were attributed to environmental/agrochemical managing factors. The broad range of pesticides investigated combined with the intensive character of the local agriculture contributed to the diversity of pesticides that were detected. However, the frequency of pesticides above the EU regulatory limit is comparable to that found in the literature concerning different Portuguese and European regions. Keywords: Environmental monitoring; vulnerable; groundwater; pesticides; lindane; endosulfan; pendimethalin; multivariate analysis
The role of a dominant macrobenthic polychaete, Scolelepis squamata, in the colonisation of defaunated tropical sediments by sandy-beach nematodes was investigated and compared with a previous ...colonisation experiment carried out on a temperate sandy beach. Experimental cylinders, equipped with lateral windows allowing infaunal colonisation, were filled with defaunated sediment containing two treatments, with and without S. squamata. These cylinders were inserted into microcosms containing sediment with indigenous meiofauna collected from the field. The treatments were incubated in the laboratory at ambient temperature and salinity for 7, 14 and 21 days. The nematode assemblages in both treatments did not differ in composition between treatments and from the natural assemblages, suggesting that all the species were equally able to colonise the experimental cores. The presence of the polychaete did not affect the development of the nematode community composition, in contrast to the results from a previous temperate-beach experiment. However, our results did not indicate whether the difference in results was caused by the different behaviour of the polychaete specimens, or by the different composition and response of the present nematode community.
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