RESUMO
The treatment of patients suffering from Aspergillus diseases is hampered due to infections with Aspergillus fumigatus that are already resistant to medical azoles. Previous work has suggested that A. fumigatus likely gains resistance through environmental azole exposure in so-called hot spots. Here, we investigated A. fumigatus resistance dynamics over time at three sites at which farmers used azole fungicides for crop protection. Over 16 months, 114 samples were taken from stockpiles of decaying plant waste. A. fumigatus and azole fungicide residues were ubiquitously present in the plant waste. On average, 105A. fumigatus CFU/g was recovered, of which roughly half were itraconazole and tebuconazole resistant. Similar tandem repeat-mediated resistance mechanisms were found in colonies cultured from plant waste as reported in clinical azole-resistant isolates. Our results show a consistent high burden of azole-resistant A. fumigatus in azole-containing plant waste and underscores the need to further investigate resistance-reducing interventions and transmission routes.IMPORTANCEAspergillus fumigatus is consistently present independently on season at a high abundance in plant waste material throughout the sampling period. Our study confirmed that long-term storage sites of azole-containing decaying plant material can indeed be considered hot spots, which can sustain resistance development and maintenance in A. fumigatus Roughly half of individual isolates were azole resistant and carried genetic mutations that are highly similar to those found in patients with azole-resistant invasive aspergillosis. Our work suggests that environmental sources of azole resistance in A. fumigatus may be important, underscoring the need for further studies on environment-to-patient transmission routes.
Assuntos
Aspergillus fumigatus/isolamento & purificação , Farmacorresistência Fúngica , Horticultura , Aspergillus fumigatus/genética , Farmacorresistência Fúngica/genética , Monitoramento Ambiental , Fungicidas Industriais/análise , Itraconazol/análise , Países Baixos , Raízes de Plantas , Triazóis/análise , Resíduos/análiseRESUMO
In long-lived animals, the challenges that threaten individual homeostasis, and the way they are dealt with, are expected to vary in an age-related manner, encompassing the progressive selection of superior phenotypes and the acquisition and improvement of key skills (e.g. foraging, breeding and fighting abilities). Since exposure to homeostatic challenges typically elevates circulating glucocorticoid (GC) levels in vertebrates (modulating the behavioural and physiological responses that mediate allostasis), we may expect concomitant age-related changes in these hormones. Here, we investigated whether the level of corticosterone (the main avian GC) deposited in feathers during regular moult reflected the expected lifelong progression of energetic challenges in a long-lived raptor, the black kite (Milvus migrans). Feather corticosterone values were highest in the youngest birds, gradually declined to reach minimum levels in prime age, 7- to 11-year-old birds, and then increased again slightly among the oldest, senescent birds (≥12 years old). This pattern mirrored the age-related changes in reproductive success and survival rates previously reported for this population, suggesting that feather corticosterone levels captured the most vulnerable and challenging periods experienced by these birds as they proceeded through life. Moreover, feather corticosterone levels were negatively related to body size, suggesting that larger birds either experienced fewer homeostatic challenges, or were better able to cope with them. Feather corticosterone measures thus provided a valuable snapshot of how allostatic loads vary along the life of individuals, supporting the idea of a tight, long-term link between cumulative physiological responses to ecological challenges and demographic performance.
Assuntos
Corticosterona , Plumas , Animais , Aves , Aves Predatórias , ReproduçãoRESUMO
AIM: To visualize by atomic force microscopy the alterations induced on Enterococcus. faecalis surface after treatment with 2 types of laser: Erbium chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and Diode laser. MATERIAL AND METHODS: Bacterial suspensions from overnight cultures of E. faecalis were irradiated during 30 seconds with the laser-lights at 1 W and 2 W of power, leaving one untreated sample as control. Surface alterations on treated E. faecalis were visualized by atomic force microscopy (AFM) and its surface roughness determined. RESULTS: AFM imaging showed that at high potency of laser both cell morphology and surface roughness resulted altered, and that several cell lysis signs were easily visualized. Surface roughness clearly increase after the treatment with Er,Cr:YSGG at 2W of power, while the other treatments gave similar values of surface roughness. The effect of lasers on bacterial surfaces visualized by AFM revealed drastic alterations. CONCLUSIONS: AFM is a good tool to evaluate surface injuries after laser treatment; and could constitute a measure of antimicrobial effect that can complete data obtained by determination of microbial viability.
Assuntos
Enterococcus faecalis/efeitos da radiação , Lasers Semicondutores , Lasers de Estado Sólido , Microscopia de Força Atômica , Estruturas Bacterianas/efeitos da radiaçãoRESUMO
This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem.
Assuntos
Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Elementos de DNA Transponíveis , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Resistência beta-Lactâmica , Códon de Iniciação , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Eletroforese em Gel de Poliacrilamida , Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Dados de Sequência Molecular , Mutagênese Insercional , Proteoma/análise , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/isolamento & purificação , Análise de Sequência de DNARESUMO
OBJECTIVE: The prospective study compares, in split-mouth design, the use of two different suture materials, silk vs. Teflon-coated, multi-filament braided polyester threads suture. MATERIAL AND METHODS: Ten edentulous or partially edentulous patients were surgically treated for implant installation. Each side was sutured with either, randomly selected one or the other suture material. Seven days postsurgically, the sutures were removed and three knots per patient and side were collected for microbiological testing. Additionally, a piece of each suture thread was analysed before clinical use to test its susceptibility for bacterial adherence. To evaluate the patient's subjective opinion, a questionnaire based on Visual Analogue Scale had to be filled out by all included patients 1 week after the intervention. RESULTS: The results showed a more pronounced plaque accumulation for silk sutures but there was not a statistical difference. The intraoperative handling of the silk sutures was less comfortable and the patient comfort was worse than Teflon-coated polyester suture. CONCLUSION: The bacterial adherence on Teflon-coated polyester suture was slightly inferior than silk suture although it did not show the expected differences.
Assuntos
Poliésteres/química , Seda/química , Suturas , Adulto , Idoso , Anti-Infecciosos Locais/uso terapêutico , Bactérias/classificação , Aderência Bacteriana/fisiologia , Carga Bacteriana , Técnicas Bacteriológicas , Clorexidina/uso terapêutico , Implantação Dentária Endóssea/instrumentação , Implantes Dentários , Placa Dentária/microbiologia , Feminino , Seguimentos , Humanos , Arcada Edêntula/cirurgia , Arcada Parcialmente Edêntula/cirurgia , Masculino , Pessoa de Meia-Idade , Antissépticos Bucais/uso terapêutico , Satisfação do Paciente , Politetrafluoretileno/química , Estudos Prospectivos , Técnicas de Sutura , Suturas/microbiologia , Escovação Dentária/instrumentaçãoRESUMO
We examined whether hypothalamic-pituitary-adrenal axis activity in the nestlings of a semialtricial raptor, the black kite (Milvus migrans), varied with advancing age, throughout the day, and in response to a number of socioecological factors presumed to affect allostatic load. Both baseline corticosterone (CORT) titers and maximum CORT levels during 30 min of handling and restraint augmented across all sampled ages, suggesting that nestlings' energetic demands and capacity to respond to perturbations increase progressively throughout development. CORT secretion also peaked in the early morning, reached minimum levels in the central hours of the day, and increased again before dusk, suggesting a possible role of CORT in the regulation of activity-inactivity patterns. Finally, nestlings raised in a year of low marsh inundation, implying lower food availability and heightened allostatic loads, exhibited higher adrenocortical responsiveness to stress than nestlings raised in years of intermediate or high flooding. The nondetectable effect of other socioecological variables, such as territory quality, temperature, or brood order, suggests that parents may be able to buffer their nestlings from adverse environmental conditions or that the effect of such factors may have been obscured by selective mortality operating before sampling. We propose that future studies increase the simultaneous use of complementary techniques (fecal sampling, feather analysis) to reach firmer and more comprehensive conclusions, especially for planning the management and conservation of sensitive species.
Assuntos
Córtex Suprarrenal/fisiologia , Ritmo Circadiano/fisiologia , Falconiformes/crescimento & desenvolvimento , Falconiformes/fisiologia , Envelhecimento/fisiologia , Animais , Corticosterona/sangue , Meio Ambiente , Falconiformes/sangue , Sistema Hipotálamo-Hipofisário/fisiologia , Sistema Hipófise-Suprarrenal/fisiologiaRESUMO
The attachment of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 28213 onto six different materials used to manufacture dental implant abutments was quantitatively determined after 2 and 24 h of contact between the materials and the bacterial cultures. The materials were topographically characterized and their wettability determined, with both parameters subsequently related to bacterial adhesion. Atomic force microscopy, interferometry, and contact angle measurement were used to characterize the materials' surfaces. The results showed that neither roughness nor nano-roughness greatly influenced bacterial attachment whereas wettability strongly correlated with adhesion. After 2 h the degree of E. coli attachment markedly differed depending on the material whereas similar differences were not observed for S. aureus, which yielded consistently higher counts of adhered cells. Nevertheless, after 24 h the adhesion of the two species to the different test materials no longer significantly differed, although on all surfaces the numbers of finally adhered E. coli were higher than those of S. aureus.
Assuntos
Aderência Bacteriana , Dente Suporte/microbiologia , Contaminação de Equipamentos/estatística & dados numéricos , Escherichia coli/fisiologia , Staphylococcus aureus/fisiologia , Escherichia coli/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimentoRESUMO
Clonal dissemination of multidrug-resistant Pseudomonas aeruginosa (MDRPA) is a major concern worldwide. The aim of this study was to explore the mechanisms leading to the carbapenem resistance of an MDRPA clone. Isolates were obtained from a surgical wound, sputum, urine and a blood culture. Pulsed-field gel electrophoresis (PFGE) showed high genomic homogeneity of these isolates and confirmed the circulation of an endemic clone belonging to serotype O4. Outer membrane protein (OMP) bands were visualized by SDS-PAGE, meropenem accumulation was measured in a bioassay and integrons were detected by PCR. Efflux pumps were studied for several antimicrobial agents and synergic combinations thereof in the presence or absence of both carbonyl cyanide m-chlorophenylhydrazone (CCCP) and Phe-Arg-ß-naphthylamide (PAßN) at final concentrations of 10 and 40 mg l(-1), respectively. On OMP electrophoretic profiles, MDRPA showed a reduction of outer membrane porin D (OprD) and PCR demonstrated the presence of a class 1 integron with a cassette encoding aminoglycoside adenyltransferase B (aadB). Meropenem accumulation was slightly higher in bacilli than in the filamentous cells that formed in the presence of antibiotics. Overexpression of the efflux pump MexAB-OprM and a functional MexXY-OprM were detected in all isolates.
Assuntos
Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla , Pseudomonas aeruginosa/efeitos dos fármacos , Antibacterianos/farmacologia , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Carbonil Cianeto m-Clorofenil Hidrazona/farmacologia , Dipeptídeos/farmacologia , Sinergismo Farmacológico , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Meropeném , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Porinas/genética , Porinas/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Tienamicinas/farmacologia , Tobramicina/farmacologiaRESUMO
BACKGROUND: Migration research is in rapid expansion and increasingly based on sophisticated satellite-tracking devices subject to constant technological refinement, but is still ripe with descriptive studies and in need of meta-analyses looking for emergent generalisations. In particular, coexistence of studies and devices with different frequency of location sampling and spatial accuracy generates doubts of data compatibility, potentially preventing meta-analyses. We used satellite-tracking data on a migratory raptor to: (1) test whether data based on different location sampling frequencies and on different position subsampling approaches are compatible, and (2) seek potential solutions that enhance compatibility and enable eventual meta-analyses. METHODOLOGY/PRINCIPAL FINDINGS: We used linear mixed models to analyse the differences in the speed and route length of the migration tracks of 36 Black kites (Milvus migrans) satellite-tagged with two different types of devices (Argos vs GPS tags), entailing different regimes of position sampling frequency. We show that different location sampling frequencies and data subsampling approaches generate large (up to 33%) differences in the estimates of route length and migration speed of this migratory bird. CONCLUSIONS/SIGNIFICANCE: Our results show that the abundance of locations available for analysis affects the tortuosity and realism of the estimated migration path. To avoid flaws in future meta-analyses or unnecessary loss of data, we urge researchers to reach an agreement on a common protocol of data presentation, and to recognize that all transmitter-based studies are likely to underestimate the actual distance traveled by the marked animal. As ecological research becomes increasingly technological, new technologies should be matched with improvements in analytical capacity that guarantee data compatibility.