RESUMO
The Vitek MS and MALDI Biotyper systems were evaluated for the identification of 221 strains belonging to less commonly isolated anaerobes and facultative anaerobes. Identifications were performed using direct deposit (DD), on-target extraction (FA) and full extraction (EXT). After DD, 29.9% and 34.3% of Gram-positive isolates (nâ¯=â¯137) as well as 36.9% and 58.3% of Gram-negative isolates (nâ¯=â¯84) were identified at the species-level with the Vitek-MS and the Biotyper system, respectively. The rates of correct species identification with the Biotyper system were significantly increased after extraction for Gram-positive isolates (FA: 75.2%, EXT: 78.1%) and Gram-negative isolates (FA: 72.6%, EXT: 78.6%). Extraction permitted to achieve higher correct species identification rates only for Gram-positive isolates (FA: 35.8%, EXT: 36.5%) with the Vitek MS. Thus, the accuracy of both systems needs to be further increased by expanding the databases. In the meantime, we recommend using a preliminary extraction step to obtain reliable results at least for the identification of Gram positive anaerobic bacteria with both systems.
Assuntos
Bactérias Anaeróbias/isolamento & purificação , Infecções Bacterianas/microbiologia , Técnicas de Tipagem Bacteriana/métodos , Espectrometria de Massas/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Bactérias Anaeróbias/química , Bactérias Anaeróbias/classificação , Bactérias Anaeróbias/genética , Infecções Bacterianas/diagnóstico , HumanosRESUMO
The Vitek MS in vitro diagnostic (IVD) and MALDI Biotyper IVD systems were evaluated for the identification of 158 strains of Actinomycetaceae. Correct species-level identification rates of 60.7% and 58.2% were obtained with the Vitek MS system after direct deposit and with the MALDI Biotyper system after on-plate formic acid treatment, respectively.
Assuntos
Actinomycetaceae/classificação , Infecções por Actinomycetales/diagnóstico , Infecções por Actinomycetales/microbiologia , Técnicas de Tipagem Bacteriana , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Humanos , Kit de Reagentes para Diagnóstico , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodosRESUMO
We report the first case of Paenibacillus glucanolyticus infection in a 65-year-old patient with type 2 diabetes who developed a cardiac device-related endocarditis. The identification of the isolate was performed using phenotypic methods, including mass spectrometry-based methods, and 16S rRNA gene sequencing.
Assuntos
Endocardite Bacteriana/diagnóstico , Endocardite Bacteriana/patologia , Marca-Passo Artificial/efeitos adversos , Paenibacillus/isolamento & purificação , Idoso , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Complicações do Diabetes , Diabetes Mellitus Tipo 2/complicações , Endocardite Bacteriana/etiologia , Endocardite Bacteriana/microbiologia , Feminino , Humanos , Espectrometria de Massas , Marca-Passo Artificial/microbiologia , Paenibacillus/química , Paenibacillus/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNAAssuntos
Actinomycetaceae/isolamento & purificação , Infecções por Actinomycetales/diagnóstico , Infecções por Actinomycetales/etiologia , Endocardite Bacteriana/diagnóstico , Endocardite Bacteriana/etiologia , Complicações Pós-Operatórias , Ressecção Transuretral da Próstata/efeitos adversos , Actinomycetaceae/efeitos dos fármacos , Infecções por Actinomycetales/tratamento farmacológico , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Bacteriemia/microbiologia , Técnicas Bacteriológicas , Endocardite Bacteriana/tratamento farmacológico , Endocardite Bacteriana/microbiologia , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/microbiologia , Resultado do Tratamento , Urina/microbiologiaRESUMO
Previous studies have suggested that procalcitonin is a reliable marker for predicting bacteremia. However, these studies have had relatively small sample sizes or focused on a single clinical entity. The primary endpoint of this study was to investigate the diagnostic accuracy of procalcitonin for predicting or excluding clinically relevant pathogen categories in patients with suspected bloodstream infections. The secondary endpoint was to look for organisms significantly associated with internationally validated procalcitonin intervals. We performed a cross-sectional study that included 35,343 consecutive patients who underwent concomitant procalcitonin assays and blood cultures for suspected bloodstream infections. Biochemical and microbiological data were systematically collected in an electronic database and extracted for purposes of this study. Depending on blood culture results, patients were classified into 1 of the 5 following groups: negative blood culture, Gram-positive bacteremia, Gram-negative bacteremia, fungi, and potential contaminants found in blood cultures (PCBCs). The highest procalcitonin concentration was observed in patients with blood cultures growing Gram-negative bacteria (median 2.2âng/mL [IQR 0.6-12.2]), and the lowest procalcitonin concentration was observed in patients with negative blood cultures (median 0.3âng/mL [IQR 0.1-1.1]). With optimal thresholds ranging from ≤0.4 to ≤0.75âng/mL, procalcitonin had a high diagnostic accuracy for excluding all pathogen categories with the following negative predictive values: Gram-negative bacteria (98.9%) (including enterobacteria [99.2%], nonfermenting Gram-negative bacilli [99.7%], and anaerobic bacteria [99.9%]), Gram-positive bacteria (98.4%), and fungi (99.6%). A procalcitonin concentration ≥10âng/mL was associated with a high risk of Gram-negative (odds ratio 5.98; 95% CI, 5.20-6.88) or Gram-positive (odds ratio 3.64; 95% CI, 3.11-4.26) bacteremia but dramatically reduced the risk of PCBCs or fungemia. In this large real-life setting experience with more than 35,000 patients, procalcitonin was highly effective at excluding bloodstream infections regardless of pathogen categories. The results from our study are limited by its cross-sectional design and deserve to be validated in prospective longitudinal studies.
Assuntos
Bacteriemia/sangue , Bactérias/isolamento & purificação , Calcitonina/sangue , Precursores de Proteínas/sangue , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Biomarcadores/sangue , Peptídeo Relacionado com Gene de Calcitonina , Estudos Transversais , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos TestesRESUMO
Analysis of bacterial DNA from fecal samples of mice is commonly performed in experimental studies. Although DNA extraction is a critical step in various molecular approaches, the efficiency of methods that may be used for DNA extraction from mice fecal samples has never been evaluated. We compared the efficiencies of six widely used commercial kits (MasterPure™ Gram Positive DNA Purification Kit, QIAamp® DNA Stool Mini Kit; NucliSENS® easyMAG®, ZR Fecal DNA MiniPrep™, FastDNA® SPIN Kit for Feces and FastDNA® SPIN Kit for Soil) and a non-commercial method for DNA isolation from mice feces and cecal contents. DNA quantity and quality were assessed by fluorometry, spectrophotometry, gel electrophoresis and qPCR. Cell lysis efficiencies were evaluated by qPCR targeting three relevant bacteria in spiked specimens. For both feces and intestinal contents, the most efficient extraction method was the FastDNA® SPIN Kit for Soil.