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To assess the antibacterial effectiveness of Lippia macrophylla essential oil (LMEO) against multidrug-resistant Acinetobacter baumannii isolates, both as a standalone treatment and in combination with conventional antibiotics. LMEO demonstrated a significant inhibitory effect on the growth of A. baumannii, with a minimum inhibitory concentration (MIC) below 500â µg/mL. Notably, LMEO was capable of reversing the antibiotic resistance of clinical isolates or reducing their MIC values when used in combination with antibiotics, showing synergistic (FICI≤0.5) or additive effects. The combination of LMEO and imipenem was particularly effective, displaying synergistic interactions for most isolates. Ultrastructural analyses supported these findings, revealing that the combination of LMEO+ceftazidime compromised the membrane integrity of the Acb35 isolate, leading to cytoplasmic leakage and increased formation of Outer Membrane Vesicles (OMVs). Taken together our results point for the use of LMEO alone or in combination as an antibacterial agent against A. baumannii. These findings offer promising avenues for utilizing LMEO as a novel antibacterial strategy against drug-resistant infections in healthcare settings, underscoring the potential of essential oils in enhancing antibiotic efficacy.
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Acinetobacter baumannii , Antibacterianos , Farmacorresistência Bacteriana Múltipla , Lippia , Testes de Sensibilidade Microbiana , Óleos Voláteis , Acinetobacter baumannii/efeitos dos fármacos , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Lippia/química , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Humanos , Relação Dose-Resposta a DrogaRESUMO
AIMS: To investigate the genetic profile and characterize antimicrobial resistance, including the main ß-lactam antibiotic resistance genes, in Acinetobacterbaumannii isolates from a tertiary hospital in Recife-PE, Brazil, in the post-COVID-19 pandemic period. METHODS AND RESULTS: Acinetobacter baumannii isolates were collected between 2023 and 2024 from diverse clinical samples. Antimicrobial resistance testing followed standardized protocols, with ß-lactamase-encoding genes detected via PCR and sequencing. Investigation into ISAba1 upstream of blaOXA-carbapenemase and blaADC genes was also conducted. Genetic diversity was assessed through ERIC-PCR. Among the 78 A. baumannii, widespread resistance to multiple antimicrobials was evident. Various acquired ß-lactamase-encoding genes (blaOXA-23,-24,-58,-143, blaVIM, and blaNDM) were detected. Furthermore, this is the first report of blaVIM-2 in A. baumannii isolates harboring either the blaOXA-23-like or the blaOXA-143 gene in Brazil. Molecular typing revealed a high genetic heterogeneity among the isolates, and multi-clonal dissemination. CONCLUSION: The accumulation of genetic resistance determinants underscores the necessity for stringent infection control measures and robust antimicrobial stewardship programs to curb multidrug-resistant strains.
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Infecções por Acinetobacter , Acinetobacter baumannii , Antibacterianos , COVID-19 , Testes de Sensibilidade Microbiana , SARS-CoV-2 , Centros de Atenção Terciária , beta-Lactamases , Acinetobacter baumannii/genética , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Brasil , Humanos , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/epidemiologia , beta-Lactamases/genética , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , SARS-CoV-2/genética , Farmacorresistência Bacteriana Múltipla/genética , Proteínas de Bactérias/genética , Masculino , Adulto , Feminino , Pessoa de Meia-Idade , Farmacorresistência Bacteriana/genéticaRESUMO
Yersinia pestis, the causative agent of plague, is a highly virulent bacterium that poses a significant threat to human health. Preserving this bacterium in a viable state is crucial for research and diagnostic purposes. This paper presents and evaluates a simple lyophilization protocol for the long-term storage of Y. pestis strains from Fiocruz-CYP, aiming to explore its impact on viability and long-term stability, while replacing the currently used methodologies. The lyophilization tests were conducted using the non-virulent Y. pestis strain EV76, subjected to the lyophilization process under vacuum conditions. Viability assessment was performed to evaluate the effects of lyophilization and storage conditions on Y. pestis under multiple temperature conditions (- 80 °C, - 20 °C, 4-8 °C and room temperature). The lyophilization protocol employed in this study consistently demonstrated its efficacy in maintaining high viability rates for Y. pestis samples in a up to one year follow-up. The storage temperature that consistently exhibited the highest recovery rates was - 80 °C, followed by - 20 °C and 4-8 °C. Microscopic analysis of the post-lyophilized cultures revealed preserved morphological features, consistent with viable bacteria. The high viability rates observed in the preserved samples indicate the successful preservation of Y. pestis using this protocol. Overall, the presented lyophilization protocol provides a valuable tool for the long-term storage of Y. pestis, offering stability, viability, and functionality. By refining the currently used methods of lyophilization, this protocol can improve long-term preservation for Y. pestis strains collections, facilitating research efforts, diagnostic procedures, and the development of preventive and therapeutic strategies against plague.
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Peste , Yersinia pestis , Humanos , Peste/microbiologia , Brasil , Liofilização , TemperaturaRESUMO
Acinetobacter baumannii is a gram-negative opportunistic bacterium that has become a major public health concern and a substantial medical challenge due to its ability to acquire multidrug resistance (MDR), extended-drug resistance, or pan-drug resistance. In this study, we evaluated the antibacterial activity of thymol and carvacrol alone or in combination against clinical isolates of MDR A. baumannii. Additionally, we used RNA-sequency to perform a comparative transcriptomic analysis of the effects of carvacrol and thymol on the Acb35 strain under different treatment conditions. Our results demonstrated that thymol and carvacrol alone, effectively inhibited the bacterial growth of MDR A. baumannii isolates, with a minimum inhibitory concentration (MIC) lower than 500 µg/mL. Furthermore, the combination of thymol and carvacrol exhibited either synergistic (FICI ≤ 0.5) or additive effects (0.5 < FICI ≤ 4), enhancing their antibacterial activity. Importantly, these compounds were found to be non-cytotoxic to Vero cells and did not cause hemolysis in erythrocytes at concentrations that effectively inhibited bacterial growth. Transcriptomic analysis revealed the down-regulation of mRNA associated with ribosomal subunit assemblies under all experimental conditions tested. However, the up-regulation of specific genes encoding stress response proteins and transcriptional regulators varied depending on the experimental condition, particularly in response to the treatment with carvacrol and thymol in combination. Based on our findings, thymol and carvacrol demonstrate promising potential as chemotherapeutic agents for controlling MDR A. baumannii infections. These compounds exhibit strong antibacterial activity, particularly in combination and lower cytotoxicity towards mammalian cells. The observed effects on gene expression provide insights into the underlying mechanisms of action, highlighting the regulation of stress response pathways.
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Acinetobacter baumannii , Timol , Animais , Chlorocebus aethiops , Timol/farmacologia , Acinetobacter baumannii/genética , Transcriptoma , Células Vero , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Farmacorresistência Bacteriana Múltipla/genética , MamíferosRESUMO
Background & objectives: During the COVID-19 pandemic, the death rate was reportedly 5-8 fold lower in India which is densely populated as compared to less populated western countries. The aim of this study was to investigate whether dietary habits were associated with the variations in COVID-19 severity and deaths between western and Indian population at the nutrigenomics level. Methods: In this study nutrigenomics approach was applied. Blood transcriptome of severe COVID-19 patients from three western countries (showing high fatality) and two datasets from Indian patients were used. Gene set enrichment analyses were performed for pathways, metabolites, nutrients, etc., and compared for western and Indian samples to identify the food- and nutrient-related factors, which may be associated with COVID-19 severity. Data on the daily consumption of twelve key food components across four countries were collected and a correlation between nutrigenomics analyses and per capita daily dietary intake was investigated. Results: Distinct dietary habits of Indians were observed, which may be associated with low death rate from COVID-19. Increased consumption of red meat, dairy products and processed foods by western populations may increase the severity and death rate by activating cytokine storm-related pathways, intussusceptive angiogenesis, hypercapnia and enhancing blood glucose levels due to high contents of sphingolipids, palmitic acid and byproducts such as CO2 and lipopolysaccharide (LPS). Palmitic acid also induces ACE2 expression and increases the infection rate. Coffee and alcohol that are highly consumed in western countries may increase the severity and death rates from COVID-19 by deregulating blood iron, zinc and triglyceride levels. The components of Indian diets maintain high iron and zinc concentrations in blood and rich fibre in their foods may prevent CO2 and LPS-mediated COVID-19 severity. Regular consumption of tea by Indians maintains high high-density lipoprotein (HDL) and low triglyceride in blood as catechins in tea act as natural atorvastatin. Importantly, regular consumption of turmeric in daily food by Indians maintains strong immunity and curcumin in turmeric may prevent pathways and mechanisms associated with SARS-CoV-2 infection and COVID-19 severity and lowered the death rate. Interpretation & conclusions: Our results suggest that Indian food components suppress cytokine storm and various other severity related pathways of COVID-19 and may have a role in lowering severity and death rates from COVID-19 in India as compared to western populations. However, large multi-centered case-control studies are required to support our current findings.
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COVID-19 , Ingredientes de Alimentos , Humanos , Nutrigenômica , Dióxido de Carbono , Lipopolissacarídeos , Pandemias , Síndrome da Liberação de Citocina , Ácido Palmítico , SARS-CoV-2 , Dieta/métodos , Comportamento Alimentar , Zinco , Chá , Ferro , TriglicerídeosRESUMO
We developed a simple new selective LB-based medium, named CYP broth, suitable for recovering long-term stored Y. pestis subcultures and for isolation of Y. pestis strains from field-caught samples for the Plague surveillance. It aimed to inhibit the growth contaminating microorganisms and enrich Y. pestis growth through iron supplementation. The performance of CYP broth on microbial growth from different gram-negative and gram-positive strains from American Type Culture Collection (ATCC®) and other clinical isolates, field-caught rodent samples, and more importantly, on several vials of ancient Y. pestis subcultures was evaluated. Additionally, other pathogenic Yersinia species such as Y. pseudotuberculosis and Y. enterocolitica were also successfully isolated with CYP broth. Selectivity tests and bacterial growth performance on CYP broth (LB broth supplemented with Cefsulodine, Irgasan, Novobiocin, nystatin and ferrioxamine E) were evaluated in comparison with LB broth without additive; LB broth/CIN, LB broth/nystatin and with traditional agar media including LB agar without additive, and LB agar and Cefsulodin-Irgasan-Novobiocin Agar (CIN agar) supplemented with 50 µg/mL of nystatin. Of note, the CYP broth had a recovery twofold higher than those of the CIN supplemented media or other regular media. Additionally, selectivity tests and bacterial growth performance were also evaluated on CYP broth in the absence of ferrioxamine E. The cultures were incubated at 28 °C and visually inspected for microbiological growth analysis and O.D.625 nm measurement between 0 and 120 h. The presence and purity of Y. pestis growth were confirmed by bacteriophage and multiplex PCR tests. Altogether, CYP broth provides an enhanced growth of Y. pestis at 28 °C, while inhibiting contaminant microorganisms. The media is a simple, but powerful tool to improve the reactivation and decontamination of ancient Y. pestis culture collections and for the isolation of Y. pestis strains for the Plague surveillance from various backgrounds. KEY POINTS: ⢠The newly described CYP broth improves the recuperation of ancient/contaminated Yersinia pestis culture collections ⢠CYP broth was also efficient in reducing environmental contamination in field-capture samples, improving Y. pestis isolation ⢠CYP broth can also be used for the isolation of Y. enterocolitica and Y. pseudotuberculosis.
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Peste , Yersinia pestis , Humanos , Ágar , Peste/microbiologia , Novobiocina/farmacologia , Nistatina , Meios de Cultura/farmacologia , Cefsulodina/farmacologiaRESUMO
Plague is a flea-borne zoonosis that affects a wide range of mammals and still causes outbreaks in human populations yearly across several countries. While crucial for proper treatment, early diagnosis is still a major challenge in low- and middle-income countries due to poor access to laboratory infrastructure in rural areas. To tackle this issue, we developed and evaluated a new Fraction 1 capsular antigen (F1)-based rapid diagnostic test (RDT) as an alternative method for plague serological diagnosis and surveillance in humans and other mammals. In this study, 187 serum samples from humans, dogs, rodents and rabbits were retrospectively assessed using the plague RDT method. To calculate its performance, results were compared to those obtained by traditional hemagglutination (HA) and ELISA, which are well-established methods in the plague routine serodiagnosis. Remarkably, the results from RDT were in full agreement with those from the ELISA and HA assays, resulting in 100% (CI 95% = 95.5-100%) of sensitivity and 100% (CI 95% = 96.6-100%) of specificity. Accordingly, the Cohen's Kappa test coefficient was 1.0 (almost perfect agreement). Moreover, the RDT showed no cross-reaction when tested with sera from individuals positive to other pathogens, such as Y. pseudotuberculosis, Yersinia enterocolitica, Anaplasma platys, Ehrlichia canis and Leishmania infantum. Although preliminary, this study brings consistent proof-of-concept results with high performance of the Plague RDT when compared to HA and ELISA. Although further human and animal population-based studies will be necessary to validate these findings, the data presented here show that the plague RDT is highly sensitive and specific, polyvalent to several mammal species and simple to use in field surveillance or point-of-care situations with instant results.
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Peste , Yersinia pestis , Animais , Testes Diagnósticos de Rotina , Cães , Humanos , Mamíferos , Peste/diagnóstico , Peste/epidemiologia , Peste/veterinária , Coelhos , Estudos RetrospectivosRESUMO
Insectivorous bats provide ecosystem services in agricultural and urban landscapes by consuming arthropods that are considered pests. Bat species inhabiting cities are expected to consume insects associated with urban areas, such as mosquitoes, flying termites, moths, and beetles. We captured insectivorous bats in the Federal District of Brazil and used fecal DNA metabarcoding to investigate the arthropod consumed by five bat species living in colonies in city buildings, and ascertained whether their predation was related to ecosystem services. These insectivorous bat species were found to consume 83 morphospecies of arthropods and among these 41 were identified to species, most of which were agricultural pests. We propose that bats may roost in the city areas and forage in the nearby agricultural fields using their ability to fly over long distances. We also calculated the value of the pest suppression ecosystem service by the bats. By a conservative estimation, bats save US$ 94 per hectare of cornfields, accounting for an annual savings of US$ 390.6 million per harvest in Brazil. Our study confirms that, regardless of their roosting location, bats are essential for providing ecosystem services in the cities, with extensive impacts on crops and elsewhere, in addition to significant savings in the use of pesticides.
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Quirópteros , Insetos , Controle Biológico de Vetores , Animais , Brasil , Cidades , Comportamento PredatórioRESUMO
Justification and Objectives: Circulating blood is sterile and the presence of microorganisms can be of clinical interest, especially in the hospital environment, being able to cause infectious processes and substantially increase morbidity and mortality. The objective of this work was to characterize the isolates of the genus Staphylococcus spp. from bloodstream infections as to the production of bacterial biofilm and resistance to the main antimicrobials used in clinical practice. Methods: Blood cultures were collected with an indication of positivity for bacterial growth from multiple sectors of the study hospital, which were subsequently processed to identify the bacterial genus through the use of phenotypic tests for Gram positive bacteria. The verification of the resistance profile was performed following the Kirby-Bauer disk diffusion. The identification of the production and quantification of the bacterial biofilm occurred following the protocol described by O'toole (2010). Results: The most frequent clinical isolate was Coagulase negative Staphylococci 38 (54.29%), followed by Staphylococcus aureus 32 (45.71%). Resistance to erythromycin, norfloxacin, levofloxacin and azithromycin was observed in most isolates (70%). Regarding methicillin, more MRSA (59.38%) than MR-CONS (47.37%) were isolated. The ICU was the place where the formation of the biofilm showed indicative data of greater adherence, which was associated with MRSA strains. Conclusion: The bacterial isolates associated with bloodstream infections showed high resistance to antimicrobials. The presence of MRSA and MR-CONS with strong and/or moderate biofilm production capacity represents a greater risk to the health of patients affected by infections caused by these agents.(AU)
Justificativa e Objetivos: O sangue circulante é estéril e a presença de microrganismos pode ter interesse clínico, especialmente no ambiente hospitalar, sendo capaz de causar processos infecciosos e aumentar substancialmente a morbimortalidade. O objetivo deste trabalho foi caracterizar os isolados do gênero Staphylococcus spp. oriundos de infecções de corrente sanguínea quanto à produção de biofilme bacteriano e resistência aos principais antimicrobianos utilizados na prática clínica. Métodos: Foram coletadas hemoculturas com indicação de positividade para o crescimento bacteriano de múltiplos setores do hospital de estudo, as quais posteriormente foram processadas para identificação do gênero bacteriano através da utilização de testes fenotípicos para bactérias Gram positivas. A verificação do perfil de resistência foi realizada seguindo a metodologia de disco difusão de Kirby-Bauer. A identificação da produção e quantificação do biofilme bacteriano ocorreu seguindo o protocolo descrito por O'toole (2010). Resultados: O isolado clínico mais frequente foi o Staphylococcus coagulase negativo 38 (54,29%), seguido pelo Staphylococcus aureus 32 (45,71%). A resistência à eritromicina, norfloxacina, levofloxacina e azitromicina foi observada na maioria dos isolados (70%). Em relação à meticilina, foram isolados mais Staphylococcus aureus resistente à meticilina (MRSA) (59,38%) que Staphylococcus coagulase negativa resistente à meticilina (MR-CONS) (47,37%). A UTI foi o local onde a formação do biofilme apresentou dados indicativos de maior aderência, sendo essa associada às cepas MRSA. Conclusão: Os isolados bacterianos associados às infecções da corrente sanguínea apresentaram elevada resistência aos antimicrobianos. A presença de MRSA e MR-CONS com forte e/ou moderada capacidade de produção de biofilme representa maior risco à saúde dos pacientes acometidos por infecções causadas por estes agentes.(AU)
Justificación y objetivos: la sangre circulante es estéril y la presencia de microorganismos puede ser de interés clínico, especialmente en el entorno hospitalario, ya que puede causar procesos infecciosos y aumentar sustancialmente la morbilidad y la mortalidad. El objetivo de este trabajo fue caracterizar los aislamientos del género Staphylococcus spp. de infecciones del torrente sanguíneo en cuanto a la producción de biopelículas bacterianas y la resistencia a los principales antimicrobianos utilizados en la práctica clínica. Métodos: Se recogieron hemocultivos con una indicación de positividad para el crecimiento bacteriano de múltiples sectores del hospital de estudio, que posteriormente se procesaron para identificar el género bacteriano mediante el uso de pruebas fenotípicas para bacterias Gram positivas. La verificación del perfil de resistencia se realizó siguiendo la metodología de difusión de disco de Kirby-Bauer. La identificación de la producción y cuantificación de la biopelícula bacteriana se produjo siguiendo el protocolo descrito por O'toole (2010). Resultados: El aislado clínico más frecuente fue Staphylococcus coagulasa negativo 38 (54.29%), seguido de Staphylococcus aureus 32 (45.71%). Se observó resistencia a la eritromicina, norfloxacina, levofloxacina y azitromicina en la mayoría de los aislamientos (70%). Con respecto a la meticilina, se aislaron más MRSA (59,38%) que MR-CONS (47,37%). La UCI fue el lugar donde la formación de la biopelícula mostró datos indicativos de una mayor adherencia, que se asoció con las cepas de MRSA. Conclusión: los aislamientos bacterianos asociados con infecciones del torrente sanguíneo mostraron una alta resistencia a los antimicrobianos. La presencia de MRSA y MR-CONS con una capacidad de producción de biopelículas fuerte y / o moderada representa un mayor riesgo para la salud de los pacientes afectados por infecciones causadas por estos agentes.(AU)
Assuntos
Staphylococcus , Resistência Microbiana a Medicamentos , Biofilmes , Hemocultura , Anti-Infecciosos , Infecção HospitalarRESUMO
Anterior Cingulate Cortex (ACC) has a crucial contribution to higher order pain processing. Photobiomodulation (PBM) has being used as integrative medicine for pain treatment and for a variety of nervous system disorders. This study evaluated the effects of PBM in the ACC of diabetic rats. Type 1 diabetes was induced by a single dose of streptozotocin (85 mg/Kg). A total of ten sessions of PBM (pulsed gallium-arsenide laser, 904 nm, 9500 Hz, 6.23 J/cm2) was applied to the rat peripheral nervous system. Glial fibrillary acidic protein (GFAP), mu-opioid receptor (MOR), glutamate receptor 1 (GluR1), and glutamic acid decarboxylase (GAD65/67) protein level expression were analyzed in the ACC of diabetic rats treated with PBM. Our data revealed that PBM decreased 79.5% of GFAP protein levels in the ACC of STZ rats. Moreover, STZ + PBM rats had protein levels of MOR increased 14.7% in the ACC. Interestingly, STZ + PBM rats had a decrease in 70.7% of GluR1 protein level in the ACC. Additionally, PBM decreased 45.5% of GAD65/67 protein levels in the ACC of STZ rats.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Giro do Cíngulo/metabolismo , Lasers , Animais , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Tipo 1/induzido quimicamente , Modelos Animais de Doenças , Processos Fotoquímicos , Ratos , EstreptozocinaRESUMO
There is no effective treatment to halt peripheral nervous system damage in diabetic peripheral neuropathy. Mitochondria have been at the center of discussions as important factors in the development of neuropathy in diabetes. Photobiomodulation has been gaining clinical acceptance as it shows beneficial effects on a variety of nervous system disorders. In this study, the effects of photobiomodulation (904 nm, 45 mW, 6.23 J/cm2, 0.13 cm2, 60 ns pulsed time) on mitochondrial dynamics were evaluated in an adult male rat experimental model of streptozotocin-induced type 1 diabetes. Results presented here indicate that photobiomodulation could have an important role in preventing or reversing mitochondrial dynamics dysfunction in the course of peripheral nervous system damage in diabetic peripheral neuropathy. Photobiomodulation showed its effects on modulating the protein expression of mitofusin 2 and dynamin-related protein 1 in the sciatic nerve and in the dorsal root ganglia neurons of streptozotocin-induced type 1 diabetes in rats.
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Gânglios Espinais/efeitos da radiação , Lasers Semicondutores , Dinâmica Mitocondrial/efeitos da radiação , Nervo Isquiático/efeitos da radiação , Animais , Glicemia/análise , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/patologia , Gânglios Espinais/metabolismo , Masculino , Ratos , Ratos Wistar , Nervo Isquiático/metabolismo , Estreptozocina/toxicidadeRESUMO
Electrical stimulation (ES) is a well-known method for guiding the behaviour of nerve cells in in vitro systems based on the response of these cells to an electric field. From this perspective, understanding how the electrochemical stimulus can be tuned for the design of a desired cell response is of great importance. Most biomedical studies propose the application of an electrical potential to cell culture arrays while examining the cell response regarding viability, morphology, and gene expression. Conversely, various studies failed to evaluate how the fine physicochemical properties of the materials used for cell culture influence the observed behaviours. Among the various materials used for culturing cells under ES, conductive polymers (CPs) are widely used either in pristine form or in addition to other polymers. CPs themselves do not possess the optimal surface for cell compatibility because of their hydrophobic nature, which leads to poor protein adhesion and, hence, poor bioactivity. Therefore, understanding how to tailor the chemical properties on the material surface will determine the obtention of improved ES platforms. Moreover, the structure of the material, either in a thin film or in porous electrospun scaffolds, also affects the biochemical response and needs to be considered. In this review, we examine how materials based on CPs influence cell behaviour under ES, and we compile the various ES setups and physicochemical properties that affect cell behaviour. This review concerns the culture of various cell types, such as neurons, fibroblasts, osteoblasts, and Schwann cells, and it also covers studies on stem cells prone to ES. To understand the mechanistic behaviour of these devices, we also examine studies presenting a more detailed biomolecular level of interaction. This review aims to guide the design of future ES setups regarding the influence of material properties and electrochemical conditions on the behaviour of in vitro cell studies.
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OBJECTIVE: To describe the molecular mechanisms of polymyxins resistance in five Enterobacteriaceae clinical isolates from a tertiary hospital of Recife, Brazil. METHODS: The species identification and the susceptibility to antimicrobials were firstly performed by automatized methods and polymyxin resistance was confirmed by broth microdilution methods. The genetic basis of resistance was characterized with WGS analyses to study their resistome, plasmidome and mobilome, by BLAST searches on reference databases. RESULTS: Five (5%) Enterobacteriaceae isolates, comprising Escherichia coli (n = 2), Klebsiella pneumoniae (n = 2) and Citrobacter freundii (n = 1) species, exhibited polymyxin resistance. The mcr-1.1 gene was found in identical IncX4-plasmids harbored by both K. pneumoniae C119 (PolB MIC = 512 mg/L) and E. coli C153 (PolB MIC = 8 mg/L). The remaining E. coli strain C027 harbored the mcr-5.1 gene on an undefined Inc-plasmid (PolB MIC 256 mg/L). Some amino acid substitutions in PmrA (S29G, G144S), PmrB (S202P; D283G, W350*, Y258N) and PhoP (I44L) was detected among the E. coli clinical isolates, however they were also found in colistin-susceptible strains and predicted as neutral alterations. The mgrB of the ST54 KPC-2-producing K. pneumoniae C151 (PolB MIC = 32 g/mL) was interrupted at 69 nt by the IS903 element. The ST117 C. freundii C156 (PolB MIC = 256 mg/L) showed the A91T substitution on HAMP domain of the histidine kinase sensor CrrB, predicted as deleterious and deemed the remarkable determinant to polymyxins resistance in this strain. CONCLUSIONS: Diverse mechanisms of polymyxins resistance were identified among clinical Enterobacteriaceae from a tertiary hospital of Recife, Brazil, such as plasmid-mediated MCR-1 and MCR-5; IS903-interruption of mgrB and mutation in CrrAB regulatory system. These findings highlight the involvement of the identified plasmids on mcr dissemination among Enterobacteriaceae; warn about co-selection of the polymyxin-resistant and KPC-producer K. pneumoniae ΔmgrB lineage by carbapenems usage; and demonstrate potential role of CrrAB on emerging of polymyxin resistance among Enterobacteriaceae, besides Klebsiella species.
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Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Infecções por Enterobacteriaceae/epidemiologia , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Polimixinas/farmacologia , Antibacterianos/uso terapêutico , Brasil/epidemiologia , Enterobacteriaceae/isolamento & purificação , Infecções por Enterobacteriaceae/tratamento farmacológico , Genes Bacterianos , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Polimixinas/uso terapêutico , Centros de Atenção TerciáriaRESUMO
Acinetobacter baumannii is an opportunistic bacterial pathogen infecting immunocompromised patients and has gained attention worldwide due to its increased antimicrobial resistance. Here, we report a comparative whole-genome sequencing and analysis coupled with an assessment of antibiotic resistance of 46 Acinetobacter strains (45 A. baumannii plus one Acinetobacter nosocomialis) originated from five hospitals from the city of Recife, Brazil, between 2010 and 2014. An average of 3,809 genes were identified per genome, although only 2,006 genes were single copy orthologs or core genes conserved across all sequenced strains, with an average of 42 new genes found per strain. We evaluated genetic distance through a phylogenetic analysis and MLST as well as the presence of antibiotic resistance genes, virulence markers and mobile genetic elements (MGE). The phylogenetic analysis recovered distinct monophyletic A. baumannii groups corresponding to five known (ST1, ST15, ST25, ST79, and ST113) and one novel ST (ST881, related to ST1). A large number of ST specific genes were found, with the ST79 strains having the largest number of genes in common that were missing from the other STs. Multiple genes associated with resistance to ß-lactams, aminoglycosides and other antibiotics were found. Some of those were clearly mapped to defined MGEs and an analysis of those revealed known elements as well as a novel Tn7-Tn3 transposon with a clear ST specific distribution. An association of selected resistance/virulence markers with specific STs was indeed observed, as well as the recent spread of the OXA-253 carbapenemase encoding gene. Virulence genes associated with the synthesis of the capsular antigens were noticeably more variable in the ST113 and ST79 strains. Indeed, several resistance and virulence genes were common to the ST79 and ST113 strains only, despite a greater genetic distance between them, suggesting common means of genetic exchange. Our comparative analysis reveals the spread of multiple STs and the genomic plasticity of A. baumannii from different hospitals in a single metropolitan area. It also highlights differences in the spread of resistance markers and other MGEs between the investigated STs, impacting on the monitoring and treatment of Acinetobacter in the ongoing and future outbreaks.
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In this study, Bacillus cereus was cultivated in a mineral medium composed of 2% frying oil and 0.12% peptone to produce a biosurfactant. The production was scaled up from flasks to 1.2-, 3.0- and 50-L bioreactors, where surface tension achieved 28.7, 27.5 and 32 mN/m and biosurfactant concentration 4.3, 4.6 and 4.7 g/L, respectively. The biosurfactant was characterized as anionic, while nuclear magnetic resonance, thin-layer chromatography and gas chromatography analyses revealed its lipopeptide nature. Toxicity tests showed survival rates of the fish Poecilia vivipara and the bivalve Anomalocardia brasiliana higher than 90% and 55%, respectively, thus suggesting the use of this biosurfactant in marine environment depollution. Moreover, the biosurfactant stimulated the growth of autochthonous microorganisms independently of the presence of motor oil in bioassays performed in seawater. These results demonstrate that the biosurfactant is biocompatible and has potential for industrial-scale production and application to bioremediation of oil spills-polluted marine environment.
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Poluição por Petróleo , Petróleo , Bacillus cereus , Biodegradação Ambiental , TensoativosRESUMO
ABSTRACT Acinetobacter baumannii is one of the most frequent Gram-negative opportunistic pathogens associated with hospital-acquired infection worldwide. We briefly describe A. baumannii isolates that were recovered from surrounding ICU bed surfaces, exhibiting multidrug resistance phenotype and belonging to some widely spread clonal complexes of clinical A. baumannii isolates.
Assuntos
Leitos/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Acinetobacter baumannii/isolamento & purificação , Unidades de Terapia Intensiva , Bactérias/isolamento & purificação , Bactérias/efeitos dos fármacos , Brasil , Testes de Sensibilidade Microbiana , Infecção Hospitalar/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Centros de Atenção Terciária , Genes BacterianosRESUMO
Acinetobacter baumannii is one of the most frequent Gram-negative opportunistic pathogens associated with hospital-acquired infection worldwide. We briefly describe A. baumannii isolates that were recovered from surrounding ICU bed surfaces, exhibiting multidrug resistance phenotype and belonging to some widely spread clonal complexes of clinical A. baumannii isolates.
Assuntos
Acinetobacter baumannii/isolamento & purificação , Leitos/microbiologia , Farmacorresistência Bacteriana Múltipla , Unidades de Terapia Intensiva , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Brasil , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos , Testes de Sensibilidade Microbiana , Centros de Atenção TerciáriaRESUMO
The work presents a full physicochemical characterization of sulfonated cellulose beads prepared from Cladophora nanocellulose intended for use in biological systems. 2,3-Dialdehyde cellulose (DAC) beads were sulfonated, and transformation of up to 50% of the aldehyde groups was achieved, resulting in highly charged and porous materials compared to the compact surface of the DAC beads. The porosity could be tailored by adjusting the degree of sulfonation, and a subsequent reduction of the aldehyde groups to hydroxyl groups maintained the bead structure without considerable alteration of the surface properties. The thermal stability of the DAC beads was significantly increased with the sulfonation and reduction reactions. Raman spectroscopy also showed to be a useful technique for the characterization of sulfonated cellulose materials.
Assuntos
Ciprofloxacina/farmacologia , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Escherichia coli/genética , beta-Lactamases/genética , Antibacterianos/farmacologia , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Brasil , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/patogenicidade , Infecções por Escherichia coli/tratamento farmacológico , Feminino , Humanos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , beta-Lactamases/metabolismoRESUMO
For better evaluation of the efficacy of low-level laser therapy in treating painful diabetic neuropathy and in protecting nerve fiber damage, we conducted a study with type 1 diabetic rats induced by streptozotocin. It is well known that diabetic peripheral neuropathy is the leading cause of pain in those individuals who suffer from diabetes. Despite the efficacy of insulin in controlling glucose level in blood, there is no effective treatment to prevent or reverse neuropathic damage for total pain relief.Male Wistar rats were divided into saline, vehicle, and treatment groups. A single intraperitoneal (i.p.) injection of streptozotocin (STZ) (85 mg/kg) was administered for the induction of diabetes. The von Frey filaments were used to assess nociceptive thresholds (allodynia). Behavioral measurements were accessed 14, 28, 48, and 56 days after STZ administration. Rats were irradiated with GaAs Laser (Gallium Arsenide, Laserpulse, Ibramed Brazil) emitting a wavelength of 904 nm, an output power of 45 mWpk, beam spot size at target 0.13 cm2, a frequency of 9500 Hz, a pulse time 60 ns, and an energy density of 6,23 J/cm2.The application of four sessions of low-level laser therapy was sufficient to reverse allodynia and protect peripheral nerve damage in diabetic rats.The results of this study indicate that low-level laser therapy is feasible to treat painful diabetic condition in rats using this protocol. Although its efficacy in reversing painful stimuli and protecting nerve fibers from damage was demonstrated, this treatment protocol must be further evaluated in biochemical levels to confirm its biological effects.