Search results for "Microbiology and Parasitology"
showing 10 items of 493 documents
Spread of Klebsiella pneumoniae ST395 non-susceptible to carbapenems and resistant to fluoroquinolones in North-Eastern France
2017
Abstract Objectives Fluoroquinolones (FQs) are a potential treatment for infections caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae that are susceptible to these agents. Methods Owing to increasing non-susceptibility to carbapenems among Enterobacteriaceae, in this study FQ resistance mechanisms were characterised in 36 ertapenem-non-susceptible Klebsiella pneumoniae isolated from North-Eastern France in 2012. The population structure was described by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Results Among the 36 isolates, 13 (36%) carried a carbapenemase encoding-gene. Decreased expression of the OmpK35-encoding gene might be…
Age reduces resistance and tolerance in malaria-infected mice.
2021
7 pages; International audience; Once infected, hosts can rely on two strategies to cope with parasites: fight them (resist the infection) or minimize the damage they induce (tolerate the infection). While there is evidence that aging reduces resistance, how tolerance varies as hosts become old has been barely studied. Here, we used a rodent malaria parasite (Plasmodium yoelii) to investigate whether 2- and 12-month old house mice differ in their capacity to resist and tolerate the infection. We found that 12-month old mice harbored higher parasitemia, showing that age reduces resistance to malaria. Infection-induced deterioration of host health was assessed using red blood cell and body ma…
Can MALDI-TOF Mass Spectrometry Reasonably Type Bacteria?
2017
International audience; Bacterial typing is crucial to tackle the spread of bacterial pathogens but current methods are time-consuming and costly. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been recently integrated into the microbiology laboratory workflow for a quick and low-cost microbial species identification. Independent research groups have successfully redirected the original function of this technology from their primary purpose to discriminate subgroups within pathogen species. However, identical bacterial subgroups could be identified by unrelated peaks by independent methods, thus limiting their robustness and exportability. We…
Enhanced emergence of antibiotic-resistant pathogenic bacteria after in vitro induction with cancer chemotherapy drugs.
2019
International audience; BACKGROUND:Infections with antibiotic-resistant pathogens in cancer patients are a leading cause of mortality. Cancer patients are treated with compounds that can damage bacterial DNA, potentially triggering the SOS response, which in turn enhances the bacterial mutation rate. Antibiotic resistance readily occurs after mutation of bacterial core genes. Thus, we tested whether cancer chemotherapy drugs enhance the emergence of resistant mutants in commensal bacteria.METHODS:Induction of the SOS response was tested after the incubation of Escherichia coli biosensors with 39 chemotherapeutic drugs at therapeutic concentrations. The mutation frequency was assessed after …
Performance of disc diffusion, MIC gradient tests and Vitek 2 for ceftolozane/tazobactam and ceftazidime/avibactam susceptibility testing of Pseudomo…
2021
AbstractObjectivesTo assess performance of disc diffusion, gradient tests and Vitek 2 system to determine the susceptibility of clinical Pseudomonas aeruginosa strains to ceftolozane/tazobactam (C/T) and ceftazidime/avibactam (CZA).MethodsTwo-hundred non-duplicate P. aeruginosa strains isolated by 47 French medical laboratories were selected to cover a wide range of C/T and CZA MICs. Performance of C/T disc (30/10 μg, Bio-Rad), CZA discs (10/4 μg) (Thermo Fisher and Bio-Rad), C/T and CZA gradient tests (Etest, BioMérieux; MIC Test Strip, Liofilchem), and AST-XN12 card of Vitek 2 system (BioMérieux) were compared with a broth microdilution (BMD) method (Thermo Fisher). MIC and disc results w…
Resistance to third-generation cephalosporins in Escherichia coli in the French community: The times they are a-changin'?
2020
Since the early 2000s, Escherichia coli resistance to third-generation cephalosporins (3GCs) has been increasing in all European countries, mainly due to the spread of extended spectrum β-lactamases (ESBLs). Here we present a retrospective study that combines resistance of E. coli to 3GCs and quinolones with data on antibiotic use in the community in a region of Northeastern France.Since 2012, an observational surveillance of antimicrobial resistance and antibiotic use in the community was conducted: data on antimicrobial resistance in E. coli isolates were collected from 11 private laboratories, and consumption data were collected from the three main healthcare insurances.A significant dec…
Characterization of ESBL-producing enterobacteria from fruit bats in an unprotected area of Makokou, Gabon.
2020
In Gabon, terrestrial mammals of protected areas have been identified as a possible source of antibiotic-resistant bacteria. Some studies on antibiotic resistance in bats have already been carried out. The main goal of our study was to detect extended-spectrum beta-lactamases (ESBLs) that are produced by enterobacteria from bats in the Makokou region in Gabon. Sixty-eight fecal samples were obtained from 68 bats caught in the forests located 1 km from the little town of Makokou. After culture and isolation, 66 Gram-negative bacterial colonies were obtained. The double-disk diffusion test confirmed the presence of ESBLs in six (20.69%) Escherichia coli isolates, four (13.79%) Klebsiella pneu…
Evaluation of five automated and one manual method for Toxoplasma and human DNA extraction from artificially spiked amniotic fluid.
2018
International audience; Objectives - Molecular detection of Toxoplasma gondii plays a crucial role in the prenatal and neonatal diagnosis of congenital toxoplasmosis (CT). Sensitivity of this diagnosis is partly related to the efficiency of parasite DNA extraction and amplification. DNA extraction methods with automated platforms have been developed. Therefore, it is essential to evaluate them in combination with adequate PCR amplification assays.Methods - In this multisite study, we investigated the suitability of two recent automated procedures for the isolation of Toxoplasma DNA from amniotic fluid (AF) (Magtration system 12GC, PSS and Freedom EVO VacS, Tecan), compared with three other …
Negative Impact of Citral on Susceptibility of Pseudomonas aeruginosa to Antibiotics
2021
Essential oils (EOs) or their components are widely used by inhalation or nebulization to fight mild respiratory bacterial infections. However, their interaction with antibiotics is poorly known. In this study we evaluated the effects of citral, the main component of lemongrass oil, on in vitro susceptibility of Pseudomonas aeruginosa to antibiotics. Exposure of strain PA14 to subinhibitory concentrations of citral increased expression of operons encoding the multidrug efflux systems MexEF-OprN and MexXY/OprM, and bacterial resistance to anti-pseudomonal antibiotics including imipenem (twofold), gentamicin (eightfold), tobramycin (eightfold), ciprofloxacin (twofold), and colistin (≥128-fold…
Using GFP-Tagged Escherichia coli to Investigate the Persistence of Fecal Bacteria in Vegetated Wetlands: An Experimental Approach
2020
The contamination of surface water by pathogenic bacteria of human origin is an important public health issue. Wetlands can be contaminated with fecal bacteria by water originating from different sources, such as wastewater treatment plants and agriculture. Escherichia coli is a commensal of the human gut flora and the major indication of fecal contamination in surface water. Little is known about the association between fecal bacteria and submerged macrophytes and how this may influence the water quality. We questioned whether macrophytes enhance or inhibit the bacterial growth in wetlands. For this purpose, we grew four different species of macrophytes (Mentha aquatica, Baldellia ranuncul…