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Classroom and staffroom floor swabs across six elementary schools in Ottawa, Canada were tested for SARS-CoV-2. Environmental test positivity did not correlate with student grade groups, school-level absenteeism, pediatric COVID-19-related hospitalizations, or community SARS-CoV-2 wastewater levels. Schools in neighbourhoods with historically elevated COVID-19 burden showed a negative but non-significant association with lower swab positivity.
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COVID-19 , SARS-CoV-2 , Instituições Acadêmicas , Humanos , COVID-19/epidemiologia , COVID-19/diagnóstico , SARS-CoV-2/isolamento & purificação , Estudos Prospectivos , Canadá/epidemiologia , Criança , Ambiente Construído , Masculino , Feminino , Ontário/epidemiologiaRESUMO
Rhizobia are Gram-negative bacteria known for their ability to fix atmospheric N2 in symbiosis with leguminous plants. Current evidence shows that rhizobia carry in most cases a variable number of plasmids, containing genes necessary for symbiosis or free-living, a common feature being the presence of several plasmid replicons within the same strain. For many years, we have been studying the mobilization properties of pSmeLPU88b from the strain Sinorhizobium meliloti LPU88, an isolate from Argentina. To advance in the characterization of pSmeLPU88b plasmid, the full sequence was obtained. pSmeLPU88b is 35.9 kb in size, had an average GC % of 58.6 and 31 CDS. Two replication modules were identified in silico: one belonging to the repABC type, and the other to the repC. The replication modules presented high DNA identity to the replication modules from plasmid pMBA9a present in an S. meliloti isolate from Canada. In addition, three CDS presenting identity with recombinases and with toxin-antitoxin systems were found downstream of the repABC system. It is noteworthy that these CDS present the same genetic structure in pSmeLPU88b and in other rhizobial plasmids. Moreover, in all cases they are found downstream of the repABC operon. By cloning each replication system in suicide plasmids, we demonstrated that each of them can support plasmid replication in the S. meliloti genetic background, but with different stability behavior. Interestingly, while incompatibility analysis of the cloned rep systems results in the loss of the parental module, both obtained plasmids can coexist together.
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Rhizobium , Sinorhizobium meliloti , Humanos , Sinorhizobium meliloti/genética , Plasmídeos/genética , DNA Bacteriano/genética , Replicon/genética , Replicação do DNA/genética , Rhizobium/genética , Proteínas de Bactérias/genéticaRESUMO
BACKGROUND: Environmental surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through wastewater has become a useful tool for population-level surveillance. Built environment sampling may provide a more spatially refined approach for surveillance in congregate living settings. METHODS: We conducted a prospective study in 10 long-term care homes (LTCHs) between September 2021 and November 2022. Floor surfaces were sampled weekly at multiple locations within each building and analyzed for the presence of SARS-CoV-2 using quantitative reverse transcriptase polymerase chain reaction. The primary outcome was the presence of a coronavirus disease 2019 (Covid-19) outbreak in the week that floor sampling was performed. RESULTS: Over the 14-month study period, we collected 4895 swabs at 10 LTCHs. During the study period, 23 Covid-19 outbreaks occurred with 119 cumulative weeks under outbreak. During outbreak periods, the proportion of floor swabs that were positive for SARS-CoV-2 was 54.3% (95% confidence interval [CI], 52 to 56.6), and during non-outbreak periods it was 22.3% (95% CI, 20.9 to 23.8). Using the proportion of floor swabs positive for SARS-CoV-2 to predict Covid-19 outbreak status in a given week, the area under the receiver-operating characteristic curve was 0.84 (95% CI, 0.78 to 0.9). Among 10 LTCHs with an outbreak and swabs performed in the prior week, eight had positive floor swabs exceeding 10% at least 5 days before outbreak identification. For seven of these eight LTCHs, positivity of floor swabs exceeded 10% more than 10 days before the outbreak was identified. CONCLUSIONS: Detection of SARS-CoV-2 on floors is strongly associated with Covid-19 outbreaks in LTCHs. These data suggest a potential role for floor sampling in improving early outbreak identification.
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COVID-19 , Humanos , SARS-CoV-2 , Teste para COVID-19 , Assistência de Longa Duração , Surtos de DoençasRESUMO
Rhizobia are Gram-negative bacteria that are able to establish a nitrogen-fixing symbiotic interaction with leguminous plants. Rhizobia genomes usually harbor several plasmids which can be transferred to other organisms by conjugation. Two main mechanisms of the regulation of rhizobial plasmid transfer have been described: quorum sensing (QS) and the rctA/rctB system. Nevertheless, new genes and molecules that modulate conjugative transfer have recently been described, demonstrating that new actors can tightly regulate the process. In this work, by means of bioinformatics tools and molecular biology approaches, two hypothetical genes are identified as playing key roles in conjugative transfer. These genes are located between conjugative genes of plasmid pRfaLPU83a from Rhizobium favelukesii LPU83, a plasmid that shows a conjugative transfer behavior depending on the genomic background. One of the two mentioned genes, rcgA, is essential for conjugation, while the other, rcgR, acts as an inhibitor of the process. In addition to introducing this new regulatory system, we show evidence of the functions of these genes in different genomic backgrounds and confirm that homologous proteins from non-closely related organisms have the same functions. These findings set up the basis for a new regulatory circuit of the conjugative transfer of plasmids. IMPORTANCE Extrachromosomal DNA elements, such as plasmids, allow for the adaptation of bacteria to new environments by conferring new determinants. Via conjugation, plasmids can be transferred between members of the same bacterial species, different species, or even to organisms belonging to a different kingdom. Knowledge about the regulatory systems of plasmid conjugative transfer is key in understanding the dynamics of their dissemination in the environment. As the increasing availability of genomes raises the number of predicted proteins with unknown functions, deeper experimental procedures help to elucidate the roles of these determinants. In this work, two uncharacterized proteins that constitute a new regulatory circuit with a key role in the conjugative transfer of rhizobial plasmids were discovered.
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Conjugação Genética , Percepção de Quorum , Plasmídeos/genética , Bactérias/genética , Nitrogênio , DNA , Transferência Genética HorizontalRESUMO
OBJECTIVES: An accurate estimate of the average number of hand hygiene opportunities per patient hour (HHO rate) is required to implement group electronic hand hygiene monitoring systems (GEHHMSs). We sought to identify predictors of HHOs to validate and implement a GEHHMS across a network of critical care units. DESIGN: Multicenter, observational study (10 hospitals) followed by quality improvement intervention involving 24 critical care units across 12 hospitals in Ontario, Canada. METHODS: Critical care patient beds were randomized to receive 1 hour of continuous direct observation to determine the HHO rate. A Poisson regression model determined unit-level predictors of HHOs. Estimates of average HHO rates across different types of critical care units were derived and used to implement and evaluate use of GEHHMS. RESULTS: During 2,812 hours of observation, we identified 25,417 HHOs. There was significant variability in HHO rate across critical care units. Time of day, day of the week, unit acuity, patient acuity, patient population and use of transmission-based precautions were significantly associated with HHO rate. Using unit-specific estimates of average HHO rate, aggregate HH adherence was 30.0% (1,084,329 of 3,614,908) at baseline with GEHHMS and improved to 38.5% (740,660 of 1,921,656) within 2 months of continuous feedback to units (P < .0001). CONCLUSIONS: Unit-specific estimates based on known predictors of HHO rate enabled broad implementation of GEHHMS. Further longitudinal quality improvement efforts using this system are required to assess the impact of GEHHMS on both HH adherence and clinical outcomes within critically ill patient populations.
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Infecção Hospitalar , Higiene das Mãos , Cuidados Críticos , Infecção Hospitalar/prevenção & controle , Eletrônica , Fidelidade a Diretrizes , Humanos , Controle de Infecções , OntárioRESUMO
BACKGROUND: Reliable reports on hand hygiene performance throughout the COVID-19 pandemic are lacking as most hospitals continue to rely on direct observation to measure this quality indicator. Using group electronic hand hygiene monitoring, we sought to assess the impact of COVID-19 on adherence to hand hygiene. METHODS: Across 12 Ontario hospitals (5 university and 7 community teaching hospitals), a group electronic hand hygiene monitoring system was installed before the pandemic to provide continuous measurement of hand hygiene adherence across 978 ward and 367 critical care beds. We performed an interrupted time-series study of institutional hand hygiene adherence in association with a COVID-19 inpatient census and the Ontario daily count of COVID-19 cases during a baseline period (Nov. 1, 2019, to Feb. 29, 2020), the pre-peak period of the first wave of the pandemic (Mar. 1 to Apr. 24, 2020), and the post-peak period of the first wave (Apr. 25 to July 5, 2020). We used a Poisson regression model to assess the association between the hospital COVID-19 census and institutional hand hygiene adherence while adjusting for the correlation within inpatient units. RESULTS: At baseline, the rate of hand hygiene adherence was 46.0% (6 325 401 of 13 750 968 opportunities) and this improved beginning in March 2020 to a daily peak of 79.3% (66 640 of 84 026 opportunities) on Mar. 30, 2020. Each patient admitted with COVID-19 was associated with improved hand hygiene adherence (incidence rate ratio [IRR] 1.0621, 95% confidence interval [CI] 1.0619-1.0623). Increasing Ontario daily case count was similarly associated with improved hand hygiene (IRR 1.0026, 95% CI 1.0021-1.0032). After peak COVID-19 community and inpatient numbers, hand hygiene adherence declined and returned to baseline. INTERPRETATION: The first wave of the COVID-19 pandemic was associated with significant improvement in hand hygiene adherence, measured using a group electronic monitoring system. Future research should seek to determine whether strategies that focus on health care worker perception of personal risk can achieve sustainable improvements in hand hygiene performance.
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COVID-19/epidemiologia , Higiene das Mãos , Pessoal de Saúde , Hospitais , Controle de Infecções/estatística & dados numéricos , COVID-19/virologia , Higiene das Mãos/métodos , Avaliação do Impacto na Saúde , Humanos , Controle de Infecções/métodos , Vigilância em Saúde PúblicaRESUMO
BACKGROUND: Health care workers have a critical role in the pandemic response to COVID-19 and may be at increased risk of infection. The objective of this study was to assess the seroprevalence of SARS-CoV-2 immunoglobulin G (IgG) antibodies among health care workers during and after the first wave of the pandemic. METHODS: We conducted a prospective multicentre cohort study involving health care workers in Ontario, Canada, to detect IgG antibodies against SARS-CoV-2. Blood samples and self-reported questionnaires were obtained at enrolment, at 6 weeks and at 12 weeks. A community hospital, tertiary care pediatric hospital and a combined adult-pediatric academic health centre enrolled participants from Apr. 1 to Nov. 13, 2020. Predictors of seropositivity were evaluated using a multivariable logistic regression, adjusted for clustering by hospital site. RESULTS: Among the 1062 health care workers participating, the median age was 40 years, and 834 (78.5%) were female. Overall, 57 (5.4%) were seropositive at any time point (2.5% when participants with prior infection confirmed by polymerase chain reaction testing were excluded). Seroprevalence was higher among those who had a known unprotected exposure to a patient with COVID-19 (p < 0.001) and those who had been contacted by public health because of a nonhospital exposure (p = 0.003). Providing direct care to patients with COVID-19 or working on a unit with a COVID-19 outbreak was not associated with higher seroprevalence. In multivariable logistic regression, presence of symptomatic contacts in the household was the strongest predictor of seropositivity (adjusted odds ratio 7.15, 95% confidence interval 5.42-9.41). INTERPRETATION: Health care workers exposed to household risk factors were more likely to be seropositive than those not exposed, highlighting the need to emphasize the importance of public health measures both inside and outside of the hospital.
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Anticorpos Antivirais/sangue , COVID-19/imunologia , Pessoal de Saúde/estatística & dados numéricos , SARS-CoV-2/imunologia , Adulto , COVID-19/diagnóstico , COVID-19/epidemiologia , COVID-19/transmissão , Estudos de Coortes , Feminino , Humanos , Imunoglobulina G/sangue , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional/estatística & dados numéricos , Ontário/epidemiologia , Estudos Prospectivos , Fatores de Risco , SARS-CoV-2/genética , Estudos Soroepidemiológicos , Centros de Atenção TerciáriaRESUMO
One of the greatest inputs of available nitrogen into the biosphere occurs through the biological N2-fixation to ammonium as result of the symbiosis between rhizobia and leguminous plants. These interactions allow increased crop yields on nitrogen-poor soils. Exopolysaccharides (EPS) are key components for the establishment of an effective symbiosis between alfalfa and Ensifer meliloti, as bacteria that lack EPS are unable to infect the host plants. Rhizobium favelukesii LPU83 is an acid-tolerant rhizobia strain capable of nodulating alfalfa but inefficient to fix nitrogen. Aiming to identify the molecular determinants that allow R. favelukesii to infect plants, we studied its EPS biosynthesis. LPU83 produces an EPS I identical to the one present in E. meliloti, but the organization of the genes involved in its synthesis is different. The main gene cluster needed for the synthesis of EPS I in E. meliloti, is split into three different sections in R. favelukesii, which probably arose by a recent event of horizontal gene transfer. A R. favelukesii strain devoided of all the genes needed for the synthesis of EPS I is still able to infect and nodulate alfalfa, suggesting that attention should be directed to other molecules involved in the development of the symbiosis.
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Strain P10 130, an isolated Bradyrhizobium strain from Argentina which promotes the growth of the leguminous plant Desmodium incanum by different mechanisms was previously selected as the best candidate for D. incanum inoculation based on broader selective criteria. A close relationship between this strain and B. yuanmingense was determined by MALDI BioTyper identification and 16S rRNA gene phylogenetic analysis. This study aimed to analyse the genome sequence of B. yuanmingense P10 130 in order to deepen our knowledge regarding its plant growth-promoting traits and to establish its phylogenetic relationship with other species of Bradyrhizobium genus. The genome size of strain P10 130 was estimated to be 7.54 Mb that consisted of 65 contigs. Genome Average Nucleotide Identity (ANI) analysis revealed that B. yuanmingense CCBAU 10071 T was the closest strain to P10 130 with ca. 96% identity. Further analysis of the genome of B. yuanmingense P10 130 identified 20 nod/nol/NOE, 14 nif/18 fix, 5 nap/5 nor genes, which may be potentially involved in nodulation, nitrogen fixation, and denitrification process respectively. Genome sequence of B. yuanmingense P10 130 is a valuable source of information to continue the research of its potential industrial production as a biofertilizer of D. incanum.
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Bradyrhizobium/genética , Fabaceae/crescimento & desenvolvimento , Genoma Bacteriano/genética , Fixação de Nitrogênio/genética , Composição de Bases/genética , DNA Bacteriano/genética , Fabaceae/microbiologia , Filogenia , Reguladores de Crescimento de Plantas/farmacologiaRESUMO
Acidic environments naturally occur worldwide and inappropriate agricultural management may also cause acidification of soils. Low soil pH values are an important barrier in the plant-rhizobia interaction. Acidic conditions disturb the establishment of the efficient rhizobia usually used as biofertilizer. This negative effect on the rhizobia-legume symbiosis is mainly due to the low acid tolerance of the bacteria. Here, we describe the identification of relevant factors in the acid tolerance of Rhizobium favelukesii using transcriptome sequencing. A total of 1924 genes were differentially expressed under acidic conditions, with â¼60% underexpressed. Rhizobium favelukesii acid response mainly includes changes in the energy metabolism and protein turnover, as well as a combination of mechanisms that may contribute to this phenotype, including GABA and histidine metabolism, cell envelope modifications and reverse proton efflux. We confirmed the acid-sensitive phenotype of a mutant in the braD gene, which showed higher expression under acid stress. Remarkably, 60% of the coding sequences encoded in the symbiotic plasmid were underexpressed and we evidenced that a strain cured for this plasmid featured an improved performance under acidic conditions. Hence, this work provides relevant information in the characterization of genes associated with tolerance or adaptation to acidic stress of R. favelukesii.
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Rhizobium , Ácidos/toxicidade , Perfilação da Expressão Gênica , Rhizobium/genética , SimbioseRESUMO
One of the most studied mechanisms involved in bacterial evolution and diversification is conjugative transfer (CT) of plasmids. Plasmids able to transfer by CT often encode beneficial traits for bacterial survival under specific environmental conditions. Rhizobium etli CFN42 is a Gram-negative bacterium of agricultural relevance due to its symbiotic association with Phaseolus vulgaris through the formation of Nitrogen-fixing nodules. The genome of R. etli CFN42 consists of one chromosome and six large plasmids. Among these, pRet42a has been identified as a conjugative plasmid. The expression of the transfer genes is regulated by a quorum sensing (QS) system that includes a traI gene, which encodes an acyl-homoserine lactone (AHL) synthase and two transcriptional regulators (TraR and CinR). Recently, we have shown that pRet42a can perform CT on the root surface and inside nodules. The aim of this work was to determine the role of plant-related compounds in the CT of pRet42a. We found that bean root exudates or root and nodule extracts induce the CT of pRet42a in the plant rhizosphere. One possibility is that these compounds are used as nutrients, allowing the bacteria to increase their growth rate and reach the population density leading to the activation of the QS system in a shorter time. We tested if P. vulgaris compounds could substitute the bacterial AHL synthesized by TraI, to activate the conjugation machinery. The results showed that the transfer of pRet42a in the presence of the plant is dependent on the bacterial QS system, which cannot be substituted by plant compounds. Additionally, individual compounds of the plant exudates were evaluated; among these, some increased and others decreased the CT. With these results, we suggest that the plant could participate at different levels to modulate the CT, and that some compounds could be activating genes in the conjugation machinery.
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Conjugação Genética/genética , Compostos Fitoquímicos/farmacologia , Plasmídeos/genética , Rhizobium etli/genética , DNA Helicases/genética , DNA Helicases/metabolismo , Phaseolus/química , Phaseolus/microbiologia , Percepção de Quorum/fisiologia , Rizosfera , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Conjugative transfer is one of the mechanisms allowing diversification and evolution of bacteria. Rhizobium etli CFN42 is a bacterial strain whose habitat is the rhizosphere and is able to form nodules as a result of the nitrogen-fixing symbiotic relationship it may establish with the roots of Phaseolus vulgaris. R. etli CFN42 contains one chromosome and six large plasmids (pRet42a - pRet42f). Most of the genetic information involved in the establishment of the symbiosis is localized on plasmid pRet42d, named as the symbiotic plasmid (pSym). This plasmid is able to perform conjugation, using pSym encoded transfer genes controlled by the RctA/RctB system. Another plasmid of CFN42, pRet42a, has been shown to perform conjugative transfer not only in vitro, but also on the surface of roots and inside nodules, using other rhizobia as recipients. In addition to the rhizobia involved in the formation of nodules, these structures have been shown to contain endophytic bacteria from different genera and species. In this work, we have explored the conjugative transfer of the pSym (pRet42d) from R. etli CFN42 to endophytic bacteria as putative recipients, using as donor a CFN42 derivative labeled with GFP in the pRet42d and RFP in the chromosome. We were able to isolate some transconjugants, which inherit the GFP, but not the RFP marker. Some of them were identified, analyzed and evaluated for their ability to nodulate. We found transconjugants from genera such as Stenotrophomonas, Achromobacter, and Bacillus, among others. Although all the transconjugants carried the GFP marker, and nod, fix, and nif genes from pRet42d, not all were able to nodulate. Ultrastructure microscopy analysis showed some differences in the structure of the nodules of one of the transconjugants. A replicon of the size of pRet42d (371 Kb) could not be visualized in the transconjugants, suggesting that the pSym or a segment of the plasmid is integrated in the chromosome of the recipients. These findings strengthen the proposal that nodules constitute a propitious environment for exchange of genetic information among bacteria, in addition to their function as structures where nitrogen fixation and assimilation takes place.
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Acid soils constitute a severe problem for leguminous crops mainly through a disturbance in rhizobium-legume interactions. Rhizobium favelukesii-an acid-tolerant rhizobium able to nodulate alfalfa-is highly competitive for nodule occupation under acid conditions but inefficient for biologic nitrogen fixation. In this work, we obtained a general description of the acid-stress response of R. favelukesii LPU83 by means of proteomics by comparing the total proteome profiles in the presence or absence of acid stress by nanoflow ultrahigh-performance liquid chromatography coupled to mass spectrometry. Thus, a total of 336 proteins were identified with a significant differential expression, 136 of which species were significantly overexpressed and 200 underexpressed in acidity. An in silico functional characterization with those respective proteins revealed a complex and pleiotropic response by these rhizobia involving components of oxidative phosphorylation, glutamate metabolism, and peptidoglycan biosynthesis, among other pathways. Furthermore, a lower permeability was evidenced in the acid-stressed cells along with several overexpressed proteins related to γ-aminobutyric acid metabolism, such as the gene product of livK, which gene was mutated. This mutant exhibited an acid-sensitive phenotype in agreement with the proteomics results. We conclude that both the γ-aminobutyric acid metabolism and a modified cellular envelope could be relevant to acid tolerance in R. favelukesii.
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Proteínas de Bactérias/análise , Proteômica/métodos , Rhizobium/química , Estresse Fisiológico/efeitos dos fármacos , Ácidos/farmacologia , Proteínas de Bactérias/fisiologia , Permeabilidade da Membrana Celular , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Mutação , Nodulação , Rhizobium/fisiologia , Solo/química , Ácido gama-Aminobutírico/genética , Ácido gama-Aminobutírico/metabolismoRESUMO
Plasmids are widely distributed in rhizobia, a group of bacteria able to establish symbiotic relationships with the roots of legume plants. Two types of conjugative transfer (CT) regulation of these elements have been described in more detail. The most prevalent is through Quorum-Sensing (QS), mediated by the interaction of the TraR regulator protein and its cognate acyl-homoserine lactone (AHL) synthesized by TraI. In this study, we analyzed rhizobial plasmids classified according to their TraR regulators into four different groups. Each group has a particular genomic architecture. In one of the groups (I-C), represented by pLPU83a from Rhizobium favelukesii LPU83, CT induction requires TraR. With manual annotation, a traI was located in the plasmid distant to the traR gene. These features make pLPU83a an interesting plasmid for studying novel mechanisms of CT regulation. We mutagenized the traI gene, and found that it does not participate in CT regulation. Furthermore, we studied whether pLPU83a is subject to QS regulation by determining CT at different growth stages (cell densities). Our results showed no positive correlation between increase in culture densities and CT induction, on the contrary a slight decrease in CT was found at higher culture densities, unlike other TraR-depending plasmids. Our results show that transfer of pLPU83a is not regulated in a QS-dependent manner, and suggest that molecules not yet identified may activate its CT. Also, accumulation of a putative inhibitor cannot be disregarded.
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Agrobacterium tumefaciens/genética , Conjugação Genética , Plasmídeos/química , Percepção de Quorum/genética , Rhizobium/genética , Acil-Butirolactonas/metabolismo , Agrobacterium tumefaciens/metabolismo , Carga Bacteriana , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Fabaceae/microbiologia , Anotação de Sequência Molecular , Filogenia , Raízes de Plantas/microbiologia , Plasmídeos/classificação , Plasmídeos/metabolismo , Rhizobium/metabolismo , Simbiose/genéticaRESUMO
ZIKV-associated Guillain-Barré syndrome presents with an accelerated clinical course compared to classic post-infectious Guillain-Barré syndrome. Clinicians should anticipate and screen patients with ZIKV infection for neurologic complications bearing in mind that these may manifest during the acute viremic phase or during early convalescence.
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Defaulting to single-lumen peripherally inserted central catheters (PICCs) ordered from non-critical care units resulted in a sustained reduction in PICC-related complications. This system of care is transferrable to other institutions, with potential for improved patient safety and efficiency in outpatient parenteral antimicrobial therapy clinics.
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Infecções Relacionadas a Cateter/prevenção & controle , Cateterismo Periférico/normas , Análise de Séries Temporais Interrompida , Idoso , Anti-Infecciosos/administração & dosagem , Cateterismo Periférico/métodos , Feminino , Humanos , Masculino , Pacientes Ambulatoriais , Segurança do Paciente/normas , Estudos Retrospectivos , Fatores de RiscoRESUMO
BACKGROUND: Prosthetic joint infections (PJI) of hip and knee arthroplasties are becoming increasingly common with an aging population and an increasing demand for these procedures. Despite attempts at standardization, medical and surgical approaches vary widely among practitioners. QUESTIONS/PURPOSES: We first sought to determine if there were specific factors associated with choice of one- versus two-stage revision. Then we investigated whether the type of revision approach influenced clinical treatment success. Finally, among two-stage revisions, we assessed if an antibiotic holiday prior to the second procedure affected clinical treatment success. METHODS: We retrospectively reviewed patients who had revision surgery for infection of a hip or knee arthroplasty between January 1, 2000, and December 31, 2013, at the Sunnybrook Health Sciences Centre and the Holland Orthopedic and Arthritic Centre. PJI cases were identified using the Ontario Joint Replacement Registry. Infection was defined by gross intraoperative evidence of infection, positive intraoperative culture(s), and/or sinus tract prior to operation. The primary outcome was treatment failure at 1 year after revision surgery based on requirement for further surgery, ongoing infection, and/or continuous suppressive antibiotics. RESULTS: Of 110 eligible patients identified, 35 patients had a one-stage and 75 patients had a two-stage revision. Choice of a one-stage approach was most influenced by particular surgeon preference and was more likely for hip revision versus knee revision (OR 3.39 (95%CI 1.85-6.23). There was no statistical difference in clinical treatment success rate between one-stage (33/35; 94.2% success) and two-stage revision (63/75; 84%; p = 0.13). Enterococcus spp. (21 versus 3%; p = 0.027) and Peptostreptococcus spp. (14 versus 1%; p = 0.042) were more common among clinical treatment failures than successes, with a trend towards the same for Staphylococcus aureus (29 versus 9%; p = 0.06). Additionally, treatment success was not influenced by whether the patient had an antibiotic holiday with a two-stage revision. CONCLUSION: Our findings confirm the uncertainty of surgical strategy for treatment of PJI in hip and knee arthroplasty. Superiority of one- versus two-stage revision and the value of antibiotic-free periods prior to definitive revision remain unclear. Large prospective studies or randomized controlled trials are needed to inform best practice for treatment of these complex clinical problems.
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Background: Our understanding of the global burden of antimicrobial resistance is limited. Complementary approaches to antimicrobial resistance surveillance are needed. Methods: We developed a Web-based/mobile platform for aggregating, analyzing, and disseminating regional antimicrobial resistance information. Antimicrobial resistance indices from existing but disparate online sources were identified and abstracted. To validate antimicrobial resistance data, in the absence of regional comparators, US and Canadian indices were aggregated and compared to existing national and state estimates. Measures of variability of antimicrobial susceptibility were determined for the United States and Canada to evaluate magnitudes of differences within countries. Results: Over 850 resistance indices globally were identified and abstracted, totaling >5 million isolates, from 340 unique locations. Resistance index coverage spanned 41 countries, 6 continents, 43 of 50 US states, and 8 of 10 Canadian provinces. When compared to reported values, aggregated resistance values for the United States and Canada during 2013 and 2014 demonstrated agreements ranging from 94% to 97%. For the United States, state-specific resistance estimates demonstrated an agreement of 92%. Large differences in antimicrobial susceptibility were seen within countries. Conclusions: Using existing nontraditional data sources, we have developed a Web-based platform for aggregating antimicrobial resistance indices to support monitoring of regional antimicrobial resistance patterns.