Search results for "microbiology"

Determinism and contingency shape metabolic complementation in an endosymbiotic consortium

2017

Bacterial endosymbionts and their insect hosts establish an intimate metabolic relationship. Bacteria offer a variety of essential nutrients to their hosts, whereas insect cells provide the necessary sources of matter and energy to their tiny metabolic allies. These nutritional complementations sustain themselves on a diversity of metabolite exchanges between the cell host and the reduced yet highly specialized bacterial metabolism-which, for instance, overproduces a small set of essential amino acids and vitamins. A well-known case of metabolic complementation is provided by the cedar aphid Cinara cedri that harbors two co-primary endosymbionts, Buchnera aphidicola BCc and Ca. Serratia sym…

Aerobic growth of Rhodococcus aetherivorans BCP1 using selected naphthenic acids as the sole carbon and energy sources

2018

Naphthenic acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that Rhodococcus aetherivorans BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL−1 . The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability. BCP1 cell adaptation responses that allowed survi…

Outbreak of ST395 KPC-Producing Klebsiella pneumoniae in a Neonatal Intensive Care Unit in Palermo, Italy

2018

Draft genome sequence and biofilm production of a carbapenemase-producing Klebsiella pneumoniae (KpR405) sequence type 405 strain isolated in Italy

2021

Rapid identification and characterization of multidrug-resistant Klebsiella pneumoniae strains is essential to diagnose severe infections in patients. In clinical routine practice, K. pneumoniae is frequently identified and characterized for outbreak investigation. Pulsed-field gel electrophoresis or multilocus sequence typing could be used, but, unfortunately, these methods are time-consuming, laborious, expensive, and do not provide any information about the presence of resistance and virulence genes. In recent years, the decreasing cost of next-generation sequencing and its easy use have led to it being considered a useful method, not only for outbreak surveillance but also for rapid ide…

Molecular epidemiology and drug-resistance mechanisms in carbapenem-resistant Klebsiella pneumoniae isolated in patients from a tertiary hospital in …

2020

Abstract Objectives The aim of this study has been to characterize carbapenem-resistant Klebsiella pneumoniae isolates and to determine the resistance mechanisms involved, the clonal relationship between strains and clinical and demographical data of the infected patients. Methods Clinical and demographical data from patients were collected and statistically analysed. Antimicrobial susceptibility testing was performed and resistance genes were detected both phenotypically and genotypically. Conjugation assays were performed to show horizontal transferability of resistance genes. Clonal relationship was also studied. Next-generation sequencing (NGS) was performed to obtain information regard…

Ebola Virus Disease Complicated by Late-Onset Encephalitis and Polyarthritis, Sierra Leone

2016

To the Editor: Ebola virus (EBOV) disease is usually an acute illness, but increasing evidence exists of persistent infections and post-Ebola syndromes. We report a case of EBOV encephalitis.

Sample Preservation, DNA or RNA Extraction and Data Analysis for High-Throughput Phytoplankton Community Sequencing

2017

Phytoplankton is the basis for aquatic food webs and mirrors the water quality. Conventionally, phytoplankton analysis has been done using time consuming and partly subjective microscopic observations, but next generation sequencing (NGS) technologies provide promising potential for rapid automated examination of environmental samples. Because many phytoplankton species have tough cell walls, methods for cell lysis and DNA or RNA isolation need to be efficient to allow unbiased nucleic acid retrieval. Here, we analyzed how two phytoplankton preservation methods, three commercial DNA extraction kits and their improvements, three RNA extraction methods, and two data analysis procedures affect…

Development of a database for the rapid and accurate routine identification of Achromobacter species by matrix-assisted laser desorption/ionization-t…

2019

International audience; Objectives: Achromobacter spp. are emerging pathogens in respiratory samples from cystic fibrosis patients. The current reference methods (nrdA-sequencing or multilocus sequence typing) can identify 18 species which are often misidentified by conventional techniques as A. xylosoxidans. A few studies have suggested that matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS) provides accurate identification of the genus but not of species. The aims of this study were (a) to generate a database for MALDI-TOF/MS Bruker including the 18 species, (b) to evaluate the suitability of the database for routine laboratory identification, and …

The unbalanced p53/SIRT1 axis may impact lymphocyte homeostasis in COVID-19 patients

2021

Abstract Background/objectives A dysregulated inflammatory profile plays an important role in coronavirus disease-2019 (COVID-19) pathogenesis. Moreover, the depletion of lymphocytes is typically associated with an unfavourable disease course. We studied the role and impact of p53 and deacetylase Sirtuin 1 (SIRT1) on lymph-monocyte homeostasis and their possible effect on T and B cell signalling. Methods Gene expression analysis and flow cytometry were performed on peripheral blood mononuclear cells (PBMC) of 35 COVID-19 patients and 10 healthy donors (HD). Inflammatory cytokines, the frequency of Annexin+ cells among CD3+ T cells and CD19+ B cell subsets were quantified. Results PBMC from …

Dosing of caspofungin based on a pharmacokinetic/pharmacodynamic index for the treatment of invasive fungal infections in critically ill patients on …

2017

Abstract Introduction The study objective was to evaluate the efficacy of different dosages of caspofungin in the treatment of invasive candidiasis and aspergillosis, in relation to the probability of pharmacokinetic/pharmacodynamic (PK/PD) target attainment, using modelling and Monte Carlo simulations in critically ill adult patients on continuous haemodiafiltration. Methods Critically ill adult patients on continuous venovenous haemodiafiltration treated with caspofungin were analysed. A population PK model was developed. Four caspofungin dosing regimens were simulated: the licensed regimen, 70 mg/day, 100 mg/day or 200 mg/day. A PK/PD target was defined as the ratio between the area unde…