Adaptive responses to static conditions in nutrient-rich cultures of luminous Ralstonia eutropha

The lux-gene fused Ralstonia eutropha, when adapting to static conditions, causes stratification of air-exposed and nutrient-rich cultures at above 0.15 mg biomass ml(-1). The O-2 respiring biofilm (luminous neuston) phase, along with the dark sub-neustonic suspension phase, develops within 5-60 min. The instability of the biphasic static culture was identified as a reason for occasionally observable oscillatory bioluminescence

Rapid assessment of antimicrobial resistance prevalence using a Lot Quality Assurance sampling approach

Increasing antimicrobial resistance (AMR) requires rapid surveillance tools, such as Lot Quality Assurance Sampling (LQAS). LQAS classifies AMR as high or low based on set parameters. We compared classifications with the underlying true AMR prevalence using data on 1335 Escherichia coli isolates from surveys of community-acquired urinary tract infection in women, by assessing operating curves, sensitivity and specificity. Sensitivity and specificity of any set of LQAS parameters was above 99% and between 79 and 90%, respectively. Operating curves showed high concordance of the LQAS classification with true AMR prevalence estimates. LQAS-based AMR surveillance is a feasible approach that provides timely and locally relevant estimates, and the necessary information to formulate and evaluate guidelines for empirical treatmen

Engineered Bacteria Based Biosensors for Monitoring Bioavailable Heavy Metals

This work presents an integrated analytical system based on immobilized engineered microorganisms and bioluminescence measurements for monitoring of bioavailable heavy metal ions (Cu being chosen as a model ion). A strain of microorganisms from Alcaligenes eutrophus (AE1239) was genetically engineered by inserting a luxCDABE operon from Vibrio fischeri under the control of a copper-induced promoter. As a result, copper ions induce bioluminescence, which is proportional to the concentration of the triggering ions, representing the basis of the design of the hereby described heavy metal biosensor. Microorganisms grown in two different media (Luria Broth and a modified mineral reconstitution medium/RM) were optimized and characterized in solution with regard to the influence of growth media and cell density in order to obtain optimal bioluminescent signals. Next, the microorganisms were immobilized in polymer matrices, compatible with fiber optics and were characterized with regard to sensitivity, selectivity, detection limit and storage stability. The lowest detection limit (1 µM) was achieved with microorganisms cultivated from glycerol stock solutions in the RM media and immobilized in a calcium alginate matrix

Biosensors for Detection of Mercury in Contaminated Soils

Biosensors based on whole bacterial cells and on bacterial heavy metal binding protein were used to determine the mercury concentration in soil. The soil samples were collected in a vegetable garden accidentally contaminated with elemental mercury 25 years earlier. Bioavailable mercury was measured using different sensors: a protein-based biosensor, a whole bacterial cell based biosensor, and a plant sensor, i.e. morphological and biochemical responses in primary leaves and roots of bean seedlings grown in the mercury-contaminated soil. For comparison the total mercury concentration of the soil samples was determined by AAS. Whole bacterial cell and protein-based biosensors gave accurate responses proportional to the total amount of mercury in the soil samples. On the contrary, plant sensors were found to be less useful indicators of soil mercury contamination, as determined by plant biomass, mercury content of primary leaves and enzyme activities

Biosensors for detection of mercury in contaminated soils

Biosensors based on whole bacterial cells and on bacterial heavy metal binding protein were used to determine the mercury concentration in soil. The soil samples were collected in a vegetable garden accidentally contaminated with elemental mercury 25 years earlier. Bioavailable mercury was measured using different sensors: a protein-based biosensor, a whole bacterial cell based biosensor, and a plant sensor, i.e. morphological and biochemical responses in primary leaves and roots of bean seedlings grown in the mercury-contaminated soil. For comparison the total mercury concentration of the soil samples was determined by AAS. Whole bacterial cell and protein-based biosensors gave accurate responses proportional to the total amount of mercury in the soil samples. On the contrary, plant sensors were found to be less useful indicators of soil mercury contamination, as determined by plant biomass, mercury content of primary leaves and enzyme activities. (C) 2004 Elsevier Ltd. All rights reserved

Biosensors for life quality. Design, development and application

none10Biosensors, combining a selective biological recognition element and a sensitive transducer, are versatile analytical tools applied more and more in different fields, such as medicine, food quality and safety control, and environment pollution monitoring. They are expected to play an increasingly important role in the improvement of life quality. In this context, the present work covers recent approaches in design and development of biosensors applied for analysis of real samples of medical, environmental or industrial relevance. The described sensors meet the sensitivity, selectivity, and response time required by their applications. Moreover, they are designed to avoid contamination of the monitored systems with undesirable components and to minimise the damage of living organisms (when it comes to in vivo monitoring).J. Castillo; S. Gáspár; S. Leth; M. Niculescu; A. Mortari; I. Bontidean; V. Soukharev; S.A. Dorneanu; A.D. Ryabov; E. CsöregiJ., Castillo; S., Gáspár; S., Leth; M., Niculescu; Mortari, Alessia; I., Bontidean; V., Soukharev; S. A., Dorneanu; A. D., Ryabov; E., Csöreg

Highly active antiretroviral therapy with or without mycophenolate mofetil in treatment-naive HIV-1 patients

Objective: To study the effect of mycophenolate mofetil (MMF) on the decay rate of plasma HIV-1 RNA and the latently infected cellular reservoir in treatment-naive patients starting antiretroviral therapy. Design: Randomized trial. Methods: A group of 19 HIV-1 infected patients (9 with a chronic and 10 with a primary infection) starting a triple antiretroviral drug regimen were randomized to a group with or without MMF. Plasma samples for HIV-1 RNA were taken and HLA-DR-CD4+ T cells were co-cultured for HIV-1 isolation. Slopes of plasma HIV-1 RNA and cellular viral load decay were calculated for the first 14 days and the first 24 weeks of treatment, respectively. Results: The median plasma HIV-1 RNA daily decay rate in chronically infected patients was 0.25 log(10) copies/ml [interquartile range (IQR), 0.18-0.30] with MMF and 0.28 log(10) copies/ml (IQR, 0.22-0.32) without MMF (P = 0.56); in primary infected patients, it was 0.31 log(10) copies/ml (IQR, 0.31-0.32) with MMF and 0.32 log(10) copies/ml (IQR, 0.26-0.34) without MMF (P = 0.75). The median daily decay rate of latently infected cells was 0.017 and 0.004 infected cells/10(6) cells in patients with and without MMF, respectively (P = 0.89). The increase in CD4 T cells was comparable between patients with and without MMF. After stopping MMF, there was an increase in the cellular reservoir in six of eight patients. Conclusion: The addition of MMF to a triple class antiretroviral regimen in treatment-naive patients does not significantly increase the plasma HIV-1 RNA decay rate or the decay rate of the latently infected cellular reservoir. (C) 2004 Lippincott Williams Wilkin

Antimicrobial resistance in uropathogens and appropriateness of empirical treatment: a population-based surveillance study in Indonesia

Urinary tract infections (UTIs) are a common reason for empirical treatment with broad-spectrum antibiotics worldwide. However, population-based antimicrobial resistance (AMR) prevalence data to inform empirical treatment choice are lacking in many regions, because of limited surveillance capacity. We aimed to assess the prevalence of AMR to commonly used antimicrobial drugs in Escherichia coli and Klebsiella pneumoniae isolated from patients with community- or healthcare-associated UTIs on two islands of Indonesia. We performed a cross-sectional patient-based study in public and private hospitals and clinics between April 2014 and May 2015. We screened patients for symptoms of UTIs and through urine dipstick analysis. Urine culture and susceptibility testing were supported by telemicrobiology and interactive virtual laboratory rounds. Surveillance data were entered in forms on mobile phones. Of 3424 eligible patients, 3380 (98.7%) were included in the final analysis, and yielded 840 positive cultures and antimicrobial susceptibility data for 657 E. coli and K. pneumoniae isolates. Fosfomycin was the single oral treatment option with resistance prevalence <20% in both E. coli and K. pneumoniae in community settings. Tigecycline and fosfomycin were the only options for treatment of catheter-associated UTIs with resistance prevalence <20%, whilst the prevalence of resistance to meropenem was 21.3% in K. pneumoniae . Patient-based surveillance of AMR in E. coli and K. pneumoniae causing UTIs indicates that resistance to the commonly available empirical treatment options is high in Indonesia. Smart AMR surveillance strategies are needed to inform policy makers and to guide intervention