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Increasing Incidence of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae (ESBL) and the Relation to Consumption of Broad-Spectrum Antimicrobial Agents 2003-2011 in a Large Area of Copenhagen, Denmark  [PDF]
Lene Nielsen, Anne Kjerulf, Magnus Arpi
Open Journal of Medical Microbiology (OJMM) , 2015, DOI: 10.4236/ojmm.2015.51005
Abstract: Purpose: To investigate 1) the development in the incidence of ESBL-producing bacteria in hospitals and primary health care, 2) the contribution of primary health care to the incidence of ESBL-producing bacteria, and 3) the development in resistance patterns for all Escherichia coli and Klebsiella pneumoniae isolates in relation to antimicrobial consumption in hospitals and primary health care. Methods: ESBL-data were retrospectively collected from bacterial isolates from all specimens received at the Department of Clinical Microbiology from 2003 to 2011 together with the corresponding patient data. ESBL-production was detected in isolates from 1067 of 59,373 patients (1.8%) with an E. coli infection and in 263 of 8660 patients (3.0%) with a K. pneumoniae infection. Results: From 2003 to 2009, an increase in patients with an ESBL-producing isolate occurred in both hospitals and primary health care at the same time as an increased consumption of broad-spectrum antimicrobial agents was seen. Interventions to reduce prescription of cephalosporins and ciprofloxacin at the hospitals from 2010 resulted in a remarkable decrease in patients with ESBL-producing K. pneumoniae whereas a continuing increase was seen in patients with ESBL-producing E. coli both at hospitals and in primary health care. The proportion of patients with community-acquired ESBL-producing E. coli was stable with an increase of only 1.4% from 2007 to 2011. Conclusions: Reduction in prescription of broad-spectrum antimicrobial agents at the hospital level had an important impact on the incidence of ESBL-producing K. pneumoniae, but not on ESBL-producing E. coli.
Review of Survey activities 2007: Evidence of stretching of the lithosphere under Denmark
Gregersen, S?ren,Nielsen, Lene Vandur,Voss, Peter
Geological Survey of Denmark and Greenland Bulletin , 2008,
Diverse modulation of spa transcription by cell wall active antibiotics in Staphylococcus aureus
Lene N Nielsen, Michael Roggenbuck, Jakob Haaber, Dan Ifrah, Hanne Ingmer
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-457
Abstract: LacZ promoter fusions of genes related to staphylococcal virulence were used to monitor the effects of antibiotics on gene expression in a disc diffusion assay. The selected genes were hla and spa encoding α-hemolysin and Protein A, respectively and RNAIII, the effector molecule of the agr quorum sensing system. The results were confirmed by quantitative real-time PCR. Additionally, we monitored the effect of subinhibitory concentrations of antibiotics on the ability of S. aureus to form biofilm in a microtiter plate assay. The results show that sub-lethal antibiotic concentrations diversely modulate expression of RNAIII, hla and spa. Consistently, expression of all three genes were repressed by aminoglycosides and induced by fluoroquinolones and penicillins. In contrast, the β-lactam sub-group cephalosporins enhanced expression of RNAIII and hla but diversely affected expression of spa. The compounds cefalotin, cefamandole, cefoxitin, ceftazidime and cefixine were found to up-regulate spa, while down-regulation was observed for cefuroxime, cefotaxime and cefepime. Interestingly, biofilm assays demonstrated that the spa-inducing cefalotin resulted in less biofilm formation compared to the spa-repressing cefotaxime.We find that independently of the cephalosporin generation, cephalosporins oppositely regulate spa expression and biofilm formation. Repression of spa expression correlates with the presence of a distinct methyloxime group while induction correlates with an acidic substituted oxime group. As cephalosporines target the cell wall penicillin binding proteins we speculate that subtle differences in this interaction fine-tunes spa expression independently of agr.Small molecules, such as antibiotics, are ubiquitous in the environment whether they originate directly from producing microorganisms or are the waste products of human activities [1,2]. While the antimicrobial activity of antibiotics target basic cellular functions like DNA, protein or cell wall synthe
Laypersons' understanding of relative risk reductions: Randomised cross-sectional study
Lene Sorensen, Dorte Gyrd-Hansen, Ivar S Kristiansen, J?rgen Nex?e, Jesper B Nielsen
BMC Medical Informatics and Decision Making , 2008, DOI: 10.1186/1472-6947-8-31
Abstract: The study was a randomised cross-sectional interview survey of a representative sample (n = 1,519) of lay people with mean age 59 (range 40–98) years in Denmark. In addition to demographic information, respondents were asked to consider a hypothetical drug treatment to prevent heart attack. Its effectiveness was randomly presented as RRR of 10, 20, 30, 40, 50 or 60 percent, and half of the respondents were presented with quantitative information on the baseline risk of heart attack. The respondents had also been asked whether they were diagnosed with hypercholesterolemia or had experienced a heart attack.In total, 873 (58%) of the respondents consented to the hypothetical treatment. While 49% accepted the treatment when RRR = 10%, the acceptance rate was 58–60% for RRR>10. There was no significant difference in acceptance rates across respondents irrespective of whether they had been presented with quantitative information on baseline risk or not.In this study, lay people's decisions about therapy were only slightly influenced by the magnitude of the effect when it was presented in terms of RRR. The results may indicate that lay people have difficulties in discriminating between levels of effectiveness when they are presented in terms of RRR.Patient autonomy is a core element of medical ethics. Patient autonomy implies that patients and doctors share responsibility for medical decision to the extent patients wish to be included. For shared decision making to be meaningful, however, patients need to have an understanding of the effectiveness of medical interventions. This usually requires the use of the risk concept. Communicating risk information is therefore a fundamental and increasingly prominent part of medical practice. Effective risk communication can enhance knowledge, involvement in decisions about testing or treatment, autonomy and empowerment of patients [1]. However poor communication may possibly lead to anxiety or lack of confidence in health care profe
Genotypic characterization and safety assessment of lactic acid bacteria from indigenous African fermented food products
David B Adimpong, Dennis S Nielsen, Kim I S?rensen, Patrick MF Derkx, Lene Jespersen
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-75
Abstract: Using molecular biology based methods and selected phenotypic tests such as catalase reaction, CO2 production from glucose, colonies and cells morphology, the isolates were identified as Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus ghanensis, Lactobacillus plantarum, Lactobacillus salivarius, Leuconostoc pseudomesenteroides, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella confusa. The bacteria were susceptible to ampicillin, chloramphenicol, clindamycin and erythromycin but resistant to vancomycin, kanamycin and streptomycin. Variable sensitivity profiles to tetracycline and gentamicin was observed among the isolates with Lb. plantarum, Lb. salivarius, W. confusa (except strain SK9-5) and Lb. fermentum strains being susceptible to tetracycline whereas Pediococcus strains and Lb. ghanensis strains were resistant. For gentamicin, Leuc. pseudomesenteroides, Lb. ghanensis and Ped. acidilactici strains were resistant to 64?mg/L whereas some W. confusa and Lb. plantarum strains had a MIC value of 16?mg/L and 32?mg/L respectively. No β-haemolytic activity was observed, however, α-haemolytic activity was observed in 27% (9) of the strains comprising Lb. salivarius (6), W. confusa (2) and Lb. delbrueckii (1) isolates.The resistance to kanamycin and vancomycin is probably an intrinsic feature since similar observations were reported in the literature for LAB. Low prevalence of pathogenicity indicator traits were observed among the isolates especially with the presence of poor haemolytic activities and they could therefore be considered as interesting candidates for selection of starter cultures or probiotics for different applications.
Novel screening assay for in vivo selection of Klebsiella pneumoniae genes promoting gastrointestinal colonisation
Boll Erik J,Nielsen Lene N,Krogfelt Karen A,Struve Carsten
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-201
Abstract: Background Klebsiella pneumoniae is an important opportunistic pathogen causing pneumonia, sepsis and urinary tract infections. Colonisation of the gastrointestinal (GI) tract is a key step in the development of infections; yet the specific factors important for K. pneumoniae to colonize and reside in the GI tract of the host are largely unknown. To identify K. pneumoniae genes promoting GI colonisation, a novel genomic-library-based approach was employed. Results Screening of a K. pneumoniae C3091 genomic library, expressed in E. coli strain EPI100, in a mouse model of GI colonisation led to the positive selection of five clones containing genes promoting persistent colonisation of the mouse GI tract. These included genes encoding the global response regulator ArcA; GalET of the galactose operon; and a cluster of two putative membrane-associated proteins of unknown function. Both ArcA and GalET are known to be involved in metabolic pathways in Klebsiella but may have additional biological actions beneficial to the pathogen. In support of this, GalET was found to confer decreased bile salt sensitivity to EPI100. Conclusions The present work establishes the use of genomic-library-based in vivo screening assays as a valuable tool for identification and characterization of virulence factors in K. pneumoniae and other bacterial pathogens.
Staphylococcus epidermidis Isolated in 1965 Are More Susceptible to Triclosan than Current Isolates
Sissel Skovgaard, Lene N?rby Nielsen, Marianne Halberg Larsen, Robert Leo Skov, Hanne Ingmer, Henrik Westh
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062197
Abstract: Since its introduction to the market in the 1970s, the synthetic biocide triclosan has had widespread use in household and medical products. Although decreased triclosan susceptibility has been observed for several bacterial species, when exposed under laboratory settings, no in vivo studies have associated triclosan use with decreased triclosan susceptibility or cross-resistance to antibiotics. One major challenge of such studies is the lack of strains that with certainty have not been exposed to triclosan. Here we have overcome this challenge by comparing current isolates of the human opportunistic pathogen Staphylococcus epidermidis with isolates collected in the 1960s prior to introduction of triclosan to the market. Of 64 current S. epidermidis isolates 12.5% were found to have tolerance towards triclosan defined as MIC≥0.25 mg/l compared to none of 34 isolates obtained in the 1960s. When passaged in the laboratory in the presence of triclosan, old and current susceptible isolates could be adapted to the same triclosan MIC level as found in current tolerant isolates. DNA sequence analysis revealed that laboratory-adapted strains carried mutations in fabI encoding the enoyl-acyl carrier protein reductase isoform, FabI, that is the target of triclosan, and the expression of fabI was also increased. However, the majority of the tolerant current isolates carried no mutations in fabI or the putative promoter region. Thus, this study indicates that the widespread use of triclosan has resulted in the occurrence of S. epidermidis with tolerance towards triclosan and that the adaptation involves FabI as well as other factors. We suggest increased caution in the general application of triclosan as triclosan has not shown efficacy in reducing infections and is toxic to aquatic organisms.
Managing the complexity of communication: regulation of gap junctions by post-translational modification
Lene N. Axelsen,Kirstine Calloe,Niels-Henrik Holstein-Rathlou,Morten S. Nielsen
Frontiers in Pharmacology , 2013, DOI: 10.3389/fphar.2013.00130
Abstract: Gap junctions are comprised of connexins that form cell-to-cell channels which couple neighboring cells to accommodate the exchange of information. The need for communication does, however, change over time and therefore must be tightly controlled. Although the regulation of connexin protein expression by transcription and translation is of great importance, the trafficking, channel activity and degradation are also under tight control. The function of connexins can be regulated by several post translational modifications, which affect numerous parameters; including number of channels, open probability, single channel conductance or selectivity. The most extensively investigated post translational modifications are phosphorylations, which have been documented in all mammalian connexins. Besides phosphorylations, some connexins are known to be ubiquitinated, SUMOylated, nitrosylated, hydroxylated, acetylated, methylated, and γ-carboxyglutamated. The aim of the present review is to summarize our current knowledge of post translational regulation of the connexin family of proteins.
Antenatal Corticosteroids and Postnatal Fluid Restriction Produce Differential Effects on AQP3 Expression, Water Handling, and Barrier Function in Perinatal Rat Epidermis
Johan Agren,Sergey Zelenin,Lill-Britt Svensson,Lene N. Nejsum,Soren Nielsen,Anita Aperia,Gunnar Sedin
Dermatology Research and Practice , 2010, DOI: 10.1155/2010/789729
Abstract: Loss of water through the immature skin can lead to hypothermia and dehydration in preterm infants. The water and glycerol channel aquaglyceroporin-3 (AQP3) is abundant in fetal epidermis and might influence epidermal water handling and transepidermal water flux around birth. To investigate the role of AQP3 in immature skin, we measured in vivo transepidermal water transport and AQP3 expression in rat pups exposed to clinically relevant fluid homeostasis perturbations. Preterm (E18) rat pups were studied after antenatal corticosteroid exposure (ANS), and neonatal (P1) rat pups after an 18?h fast. Transepidermal water loss (TEWL) and skin hydration were determined, AQP3 mRNA was quantified by RT-PCR, and in-situ hybridization and immunocytochemistry were applied to map AQP3 expression. ANS resulted in an improved skin barrier (lower TEWL and skin hydration), while AQP3 mRNA and protein increased. Fasting led to loss of barrier integrity along with an increase in skin hydration. These alterations were not paralleled by any changes in AQP3. To conclude, antenatal corticosteroids and early postnatal fluid restriction produce differential effects on skin barrier function and epidermal AQP3 expression in the rat. In perinatal rats, AQP3 does not directly determine net water transport through the skin. 1. Background Extremely preterm infants lose large amounts of water from the skin surface early after birth on account of their immature skin [1, 2]. In these infants, excessive water loss carries an increased risk for dehydration and hypothermia, conditions that have important clinical consequences. The function of the skin as a barrier against the environment, and the amount of transepidermal water loss (TEWL), depends on the integrity of the outer layer of the epidermis, the stratum corneum [3, 4]. There is a clear relation between the maturation of barrier function and the content and structural organization of the stratum corneum lipids [4, 5]. The water and glycerol transporting integral membrane protein aquaglyceroporin-3 (AQP3) and the water channel aquaporin-1 (AQP1) are present in the skin [6, 7] and have also been shown to be abundantly expressed in the fetal rat [8]. Most interestingly, AQP3 is expressed at the plasma membrane of keratinocytes of the basal cell layers of the epidermis [8]. A role of AQP3 in epidermal hydration and/or transepidermal water transport in immature skin lacking a competent barrier has been suggested [8, 9], but little is known about its precise function and regulation. Treatment with antenatal corticosteroids (ANSs) is
CATCHprofiles: Clustering and Alignment Tool for ChIP Profiles
Fiona G. G. Nielsen, Kasper Galschi?t Markus, Rune M?llegaard Friborg, Lene Monrad Favrholdt, Hendrik G. Stunnenberg, Martijn Huynen
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0028272
Abstract: Chromatin Immuno Precipitation (ChIP) profiling detects in vivo protein-DNA binding, and has revealed a large combinatorial complexity in the binding of chromatin associated proteins and their post-translational modifications. To fully explore the spatial and combinatorial patterns in ChIP-profiling data and detect potentially meaningful patterns, the areas of enrichment must be aligned and clustered, which is an algorithmically and computationally challenging task. We have developed CATCHprofiles, a novel tool for exhaustive pattern detection in ChIP profiling data. CATCHprofiles is built upon a computationally efficient implementation for the exhaustive alignment and hierarchical clustering of ChIP profiling data. The tool features a graphical interface for examination and browsing of the clustering results. CATCHprofiles requires no prior knowledge about functional sites, detects known binding patterns “ab initio”, and enables the detection of new patterns from ChIP data at a high resolution, exemplified by the detection of asymmetric histone and histone modification patterns around H2A.Z-enriched sites. CATCHprofiles' capability for exhaustive analysis combined with its ease-of-use makes it an invaluable tool for explorative research based on ChIP profiling data. CATCHprofiles and the CATCH algorithm run on all platforms and is available for free through the CATCH website: http://catch.cmbi.ru.nl/. User support is available by subscribing to the mailing list catch-users@bioinformatics.org.
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