L P Andersen

Lithuanian University of Health Sciences, Caunas, Kauno Apskritis, Lithuania

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Publications (114)425.17 Total impact

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    ABSTRACT: OBJECTIVE: Resistance to antibiotics is the major cause of treatment failure of Helicobacter pylori infection. A study was conducted to assess prospectively the antibacterial resistance rates of H pylori in Europe and to study the link between outpatient antibiotic use and resistance levels in different countries. DESIGN: Primary antibiotic resistance rates of H pylori were determined from April 2008 to June 2009 in 18 European countries. Data on yearly and cumulative use over several years of systemic antibacterial agents in ambulatory care for the period 2001-8 were expressed in Defined Daily Doses (DDD) per 1000 inhabitants per day. The fit of models and the degree of ecological association between antibiotic use and resistance data were assessed using generalised linear mixed models. RESULTS: Of 2204 patients included, H pylori resistance rates for adults were 17.5% for clarithromycin, 14.1% for levofloxacin and 34.9% for metronidazole, and were significantly higher for clarithromycin and levofloxacin in Western/Central and Southern Europe (>20%) than in Northern European countries (<10%). Model fit improved for each additional year of antibiotic use accumulated, but the best fit was obtained for 2005. A significant association was found between outpatient quinolone use and the proportion of levofloxacin resistance (p=0.0013) and between the use of long-acting macrolides only and clarithromycin resistance (p=0.036). CONCLUSION: In many countries the high rate of clarithromycin resistance no longer allows its empirical use in standard anti-H pylori regimens. The knowledge of outpatient antibiotic consumption may provide a simple tool to predict the susceptibility of H pylori to quinolones and to macrolides and to adapt the treatment strategies.
    Gut 01/2013; 62(1):34-42. · 10.73 Impact Factor
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    ABSTRACT: The study evaluated the changes in the prevalence of Helicobacter pylori strains with primary resistance to antibiotics during the last 10 years in Lithuania. H. pylori susceptibilities to antibiotics were tested in 89 patients in 1998, in 81 patients in 2001 and in 90 patients in 2007/2008. Susceptibility to metronidazole, clarithromycin, amoxicillin and tetracycline was tested using E-test or agar dilution method. Susceptibility to ciprofloxacin was only tested in 2007/2008. Data about utilization of all authorized and available on market macrolides and clindamycin in Lithuania during 2003-2007 were evaluated using WHO ATC/DDD methodology. A total of 260 H. pylori strains cultured from untreated adult patients were investigated. Primary resistance rates (1998, 2001 and 2007/2008) for metronidazole were 24.7%, 33.3%, and 35.6%, for clarithromycin 1.1%, 3.7%, and 3.3% and for tetracycline 0%, 2.5% and 0% respectively. No cases of amoxicillin resistance have been detected. The resistance rate for ciprofloxacin was 5.6% in 2007/2008. Data of total macrolides and clarithromycin utilization in Lithuania revealed that despite an increase of consumption of these drugs in Lithuania during 2003-2007 in 1.5 times, the total macrolide consumption remains one of the lowest in Europe. We have not observed any significant changes in the susceptibility of H. pylori to the most widely used antibiotics during the recent 10-year period. The low resistance rate to clarithromycin might be related to the policy to avoid use of macrolides as first-line treatment for pulmonary and other infections.
    Apmis 10/2012; · 2.07 Impact Factor
  • Lone Rasmussen, Leif Percival Andersen
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    ABSTRACT: Helicobacter pylori is a Gram-negative, microaerophilic curved rod, that possesses an unipolar bundle of two to six flagella which enables it to move to a specific target with high concentration of chemoattractants, such as urea. H. pylori is a pathogenic bacterium, which is present in more than half of the population worldwide with a range from 20 to 30% in developed countries to 60–80% in developing countries.
    10/2010: pages 161-166;
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    ABSTRACT: Enterococcus species are common in nosocomial bloodstream infections and their incidence is rising. Although well recognized in several serious bacterial infections, the influence of appropriate antimicrobial therapy in enterococcal bacteraemia has not been fully settled. The aim of the study was to determine whether administration of inappropriate antibiotics in enterococcal bacteraemia is an independent risk factor for mortality, among other known and suspected risk factors. We conducted a cohort study of E. faecalis/faecium bacteraemia during a 3-year period at a single tertiary care hospital in Denmark. Patients with growth of non-enterococcus co-pathogens apart from the enterococcal bacteraemia were also included, as were patients with repeated enterococcal bacteraemia. Time to appropriate antimicrobial therapy was counted from the first episode. Appropriate antibiotic therapy was defined as any therapy with documented clinical effect, in vitro activity and a minimum treatment length of 6 days. Multivariate regression models were built to determine the independent risk factors for mortality. We included 196 patients with enterococcal bacteraemia. Appropriate antibiotics for at least 6 days were administered in 146 of these (74%). Thirty-day mortality was 26%. Multivariate logistic regression identified independent predictors of 30-day all-cause mortality: appropriate antimicrobial therapy for ≥ 6 days (odds ratio for mortality 0.33, 0.14-0.79), ICU admission (4.2, 1.7-10), thrombocytopenia (3.9, 1.6-9.3), chronic liver failure (3.3, 1.1-10) and age ≥ 60 years (2.2, 0.99-5.0). Antibiotics not appropriately covering enterococci are frequently administered empirically in suspected bloodstream infections. Inappropriate antibiotic therapy was an independent risk factor for mortality in enterococcal bacteraemia.
    Clinical Microbiology and Infection 10/2010; 17(7):1078-83. · 4.58 Impact Factor
  • L P Andersen, P Lange, M Tvede
    European Journal of Clinical Microbiology 07/2010; 29(7):891-2. · 3.02 Impact Factor
  • Jalal Alimoradi, Lone Rasmussen, Leif Percival Andersen
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    ABSTRACT: Helicobacter pylori (H. pylori) is recognized as the causative of several gastroduodenal disorders. The discovery of H. pylori revolutionized the treatment for ulcus pepticum. Antibiotics combined with proton pump inhibitors or bismuth have been effective in the treatment of H. pylori infections, but there is an emerging problem with H. pylori resistance against the most frequently used antibiotics, which substantially impairs the treatment of H. pylori-associated disorders. In this article the focus is on the prevalence of H. pylori resistance, its clinical implications and the molecular mechanisms behind resistance development.
    Ugeskrift for laeger 05/2010; 172(20):1516-21.
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    ABSTRACT: Heat-stable antigens from Helicobacter pylori were investigated for the detection of serum IgG, IgA and IgM antibodies against H. pylori by an ELISA technique. Antibody titers against H. pylori were measured in 167 dyspeptic patients, of whom 96 were H. pylori positive confirmed by culture or microscopy, and in 482 controls (0–98 years). Increased IgG antibody titers were found significantly more often in dyspeptic patients with active chronic gastritis than in patients with normal morphology, as well as in H. pylori-positive patients as compared to H. pylori-negative patients, independent of the endoscopic findings. The heat-stable antigens were compared with acid glycine-extracted antigens and a high degree of concordance was found in the results obtained with the two antigen preparations. The differences in the IgA antibody titers against H. pylori between H. pylori-positive and H. pylori-negative dyspeptic patients were significant and may be useful to confirm a borderline IgG result. No differences were found in IgM antibody titer between H. pylori-positive and -negative patients. The greatest age-dependent increase in IgG and IgA antibody titers was found in children, and if a lower cut-off level is used for children than for adults, as has been proposed, the proportion of people with increased antibody titers against H. pylori would be almost constant from the age of between five and 10 years until the time between 61 and 80 years. Comparison of H. pylori IgG antibodies with IgG antibodies against Campylobacter jejuni and total antibodies against cytomegalovirus (CMV) showed a greater similarity between H. pylori and C. jejuni (R = 0.51) than between H. pylori and CMV (R = 0.22). This may possibly be caused by cross-reactions between H. pylori and C. jejuni. The H. pylori heat-stabile antigen seems not to be very different from other crude H. pylori antigens like acid glycine-extracted antigens, but purification and characterization of the antigens are needed to improve antibody assays.
    Apmis 08/2009; 100(7‐12):779 - 789. · 2.07 Impact Factor
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    Leif Percival Andersen, Lone Rasmussen
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    ABSTRACT: Electron microscopic studies have shown that Helicobacter pylori occurs in three stages: spiral forms, coccoid forms and degenerative forms. The spiral forms are viable, culturable, virulent and can colonize experimental animals and induce inflammation. The coccoid forms may also be viable but are nonculturable, less virulent and are less likely to colonize and induce inflammation in experimental animals than the spiral forms. The degenerative forms are pyknotic, nonculturable, coccoid forms of dead H. pylori. These forms cannot be cultured and the cell membrane has disintegrated but gene material can be detected by PCR in water supplies. There is no substantial evidence for viable H. pylori persisting in water supplies. Epidemiological studies suggest that environmental water is a risk factor for H. pylori infection when compared with tap water, and formation of H. pylori biofilm cannot be excluded. Helicobacter pylori does not seem to take part in biofilm formation in the oral cavity even though the bacterium may be detected.
    FEMS Immunology & Medical Microbiology 05/2009; 56(2):112-5. · 2.68 Impact Factor
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    Rune Aabenhus, Unne Stenram, Leif Percival Andersen, Henrik Permin, Asa Ljungh
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    ABSTRACT: To infect mice with atypical Campylobacter concisus (C. concisus) for the first time. Three separate experiments were conducted in order to screen the ability of five clinical C. concisus isolates of intestinal origin and the ATCC 33237 type strain of oral origin to colonize and produce infection in immunocompetent BALB/cA mice. The majority of the BALB/cA mice were treated with cyclophosphamide prior to C. concisus inoculation to suppress immune functions. Inoculation of C. concisus was performed by the gastric route. C. concisus was isolated from the liver, ileum and jejunum of cyclophosphamide-treated mice in the first experiment. No C. concisus strains were isolated in the two subsequent experiments. Mice infected with C. concisus showed a significant loss of body weight from day two through to day five of infection but this decreased at the end of the first week. Histopathological examination did not consistently find signs of inflammation in the gut, but occasionally microabscesses were found in the liver of infected animals. Transient colonization with C. concisus was observed in mice with loss of body weight. Future studies should concentrate on the first few days after inoculation and in other strains of mice.
    World Journal of Gastroenterology 01/2009; 14(45):6954-9. · 2.55 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the efficacy of the natural antioxidant astaxanthin in functional dyspepsia in different doses and compared with placebo. The study was a controlled, prospective, randomized, and double blind trial. Patients with functional dyspepsia, divided into three groups with 44 individuals in each group (placebo, 16mg, or 40mg astaxanthin, respectively). Participants were asked to accept gastroscopy before treatment, together with questionnaires: GSRS and SF-36. Urea breath test (UBT) was done before the treatment. The primary objective was to test the hypothesis that the antioxidant astaxanthin at two doses regimens compared to placebo should ameliorate gastrointestinal discomfort measured as GSRS in patients with functional dyspepsia, who were either positive or negative for Helicobacter pylori, after 4 weeks of treatment. At the end of therapy (week 4) no difference between the three treatment groups was observed regarding mean Gastrointestinal Symptom Rating Scale (GSRS) scores of abdominal pain, indigestion and reflux syndromes. The same results were observed at the end of follow-up. However reduction of reflux syndrome before treatment to week 4 was significantly pronounced in the higher (40mg) dose compared to the other treatment groups (16mg and placebo, p=0.04). In general, no curative effect of astaxanthin was found in functional dyspepsia patients. Significantly greater reduction of reflux symptoms were detected in patients treated with the highest dose of the natural antioxidant astaxanthin. The response was more pronounced in H. pylori-infected patients.
    Phytomedicine: international journal of phytotherapy and phytopharmacology 07/2008; 15(6-7):391-9. · 2.97 Impact Factor
  • Leif Percival Andersen
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    ABSTRACT: When Helicobacter pylori arrives in the human stomach, it may penetrate the mucin layer and adhere to the gastric epithelial cells or it may pass through the stomach without colonizing the mucosa. In this paper, the colonization process and the ensuing immunological response will be briefly described. Urease production is necessary for H. pylori to establish a pH-neutral microenvironment around the bacteria. The flagella enable the bacteria to move and the shape of H. pylori makes it possible to penetrate the mucin layer where it comes into contact with the gastric epithelial cells. H. pylori contains several adhesins that enable it to adhere to the epithelial cells. This adherence activates IL-8 which, together with bacterial antigens, attracts polymorphs and monocytes and causes acute gastritis. Antigen-presenting cells activate lymphocytes and other mononuclear cells that are attracted to the inflamed mucosa, causing chronic superficial gastritis and initiating a cytotoxic or an antigen-producing Th response. The infection is established within a few weeks after the primary exposure to H. pylori. After this initial colonization, many chemical, biochemical, and immunologic reactions take place that are of importance in the progress of the infection and the development of disease.
    Helicobacter 12/2007; 12 Suppl 2:12-5. · 3.51 Impact Factor
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    ABSTRACT: The chronic active inflammation caused by Helicobacter pylori is dominated by neutrophils, macrophages, lymphocytes and plasma cells. Several interleukins are involved in the inflammatory process. The aim of this study was to investigate the effect of astaxanthin on gastric inflammation in patients with functional dyspepsia. Forty-four consecutive patients were included, and biopsies were examined for IL-4, IL-6, IL-8, IL-10, interferon-gamma, CD4, CD8, CD14, CD19, CD25 and CD30. Patients were randomized: 21 patients were treated with 40 mg of astaxanthin daily, and 23 patients were treated with a placebo. There was a significant decrease in gastric inflammation in H. pylori-positive patients from both groups. There were no significant changes in the density of H. pylori or in any of the interleukins during or after treatment. There was a significant up-regulation of CD4 and down-regulation of CD8 in patients with H. pylori treated with astaxanthin. Astaxanthin had an effect on the inflammation and on the density of H. pylori in mice in a study where the diet could be standardized without antioxidants (Bennedsen et al., 1999). These dietary conditions are impossible in studies involving humans, and may be due to the minor effect when the host have access to antioxidants in their diet.
    FEMS Immunology & Medical Microbiology 08/2007; 50(2):244-8. · 2.68 Impact Factor
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    ABSTRACT: Helicobacter pylori is an important pathogen in major gastroduodenal diseases, including inflammation with ulceration and gastric malignancies. Alterations in H. pylori associated cell turnover in gastric epithelial cells are examined in relation to inflammatory activity, bacteria load and cytokines which may improve knowledge concerning the outcome of gastric diseases caused by H. pylori. Antral biopsies from 42 dyspeptic patients including 27 H. pylori-positive and 15 H. pylori-negative patients were tested for apoptotic activity by the TUNEL assay, and immuno-histochemically for p53 and the proliferative marker Ki-67. H. pylori infection, bacteria load and inflammatory activity were associated with increased cell turnover as judged by enhanced activities of TUNEL, p53 and Ki-67. Only p53 was significantly correlated to IFN-gamma, IL-8 and IL-10. The H. pylori-positive state was furthermore accompanied by varying degrees of altered distribution pattern of the markers studied, with occasional presence of apoptosis in the deeper pit zones, upward extension of Ki-67 and to a lesser degree of p53. Given a similar pattern of change in proliferation and apoptosis in some neoplastic lesions in other parts of the gastrointestinal tract, such studies in cell turnover may provide insights valuable in the investigations of potential precursors of gastric malignancies.
    FEMS Immunology & Medical Microbiology 08/2007; 50(2):206-12. · 2.68 Impact Factor
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    ABSTRACT: Helicobacter pylori is a major factor for the development of gastric cancer. The aim of this study was to define serum antibody patterns associated with H. pylori infection in patients with gastric cancer using a Western blot technique. Serum samples collected from 115 patients with gastric cancer and 110 age- and gender-matched patients without gastrointestinal diseases were tested for IgG antibodies to H. pylori antigens (outer membrane proteins and whole cell preparations). No significant differences were found between patients with and without gastric cancer using outer membrane proteins (82% and 73%, P>0.05) or whole cell antigens (84% and 76%, P>0.05), respectively. The significant differences between patients with and without gastric cancer were associated with bands of 94 kDa (54% and 20%, P<0.001) and 30 kDa (65% and 44%, P<0.01). A combination of antibodies to 85 kDa (VacA) and 120 kDa (CagA) was significantly (P<0.01) more frequent in gastric cancer patients than in patients without gastric cancer. The detection of antibodies to 94- and 30-kDa bands, in association with the determination of serum antibodies to CagA+/VacA+, may have a prospective value in assessment of the risk of developing of gastric cancer.
    FEMS Immunology & Medical Microbiology 07/2007; 50(2):220-5. · 2.68 Impact Factor
  • International Journal of Antimicrobial Agents 03/2007; 29. · 4.42 Impact Factor
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    ABSTRACT: This article describes an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in two institutions for multi-handicapped children in Copenhagen. The aim of the study was to determine whether it was possible to eradicate MRSA in a setting with multi-handicapped children and staff where there was a high degree of physical interaction. This was a prospective interventional uncontrolled cohort study that took place from January 2003 to March 2005. All individuals in close contact with the two institutions and/or in close contact with an MRSA-colonized subject from the outbreak were included in the study: 38 children, 60 staff members and 12 close relatives of colonized subjects. Infection control measures included screening all individuals. When MRSA infection or colonization was found, an attempt was made to eradicate MRSA, staff education was undertaken and attempts were made to determine the route of transmission. Eleven individuals were found to be positive for MRSA (10.0%). All isolates were identical by pulsed-field gel electrophoresis and harboured the staphylococcal cassette chromosome mec (SCCmec) type IV. All colonized and infected individuals were associated with a single room in one of the institutions. MRSA was eradicated from all the colonized and infected subjects. This study shows that it is possible to control an MRSA outbreak in institutions for multi-handicapped children where there is a high degree of physical contact.
    Journal of Hospital Infection 06/2006; 63(1):84-92. · 2.86 Impact Factor
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    ABSTRACT: Microbial typing is a useful tool in clinical epidemiology for defining the source and route of infection, for studying the persistence and reinfection rates, clonal selection in the host and bacterial evolution. Phenotypic methods such as biotyping, serotyping and hemagglutinin typing have little discriminatory power compared to genotypic methods concerning the typing of Helicobacter pylori. Therefore great efforts have been made to establish useful molecular typing methods. In this context, the most frequently used genotypic methods are described based on our own experience and the literature: (1) restriction endonuclease analysis, (2) endonuclease analysis using pulsed-field gel electrophoresis, (3) ribotyping, (4) polymerase chain reaction (using either random primers or repetitive DNA sequence primers), and (5) polymerase chain reaction-restriction fragment length polymorphism analysis of e.g. the urease genes. Furthermore, reproducibility, discriminatory power, ease of performance and interpretation, cost and toxic procedures of each method are assessed. To date no direct comparison of all the molecular typing methods described has been performed in the same study with the same H. pylori strains. However, PCR analysis of the urease gene directly on suspensions of H. pylori or gastric biopsy material seems to be useful for routine use and applicable in specific epidemiological situations.
    FEMS Immunology & Medical Microbiology 01/2006; 24(2):193 - 199. · 2.68 Impact Factor
  • E. T. Jensen, A. L. Olsen, L. P. Andersen
    Journal of Hospital Infection 01/2006; 64. · 2.86 Impact Factor
  • Rune Aabenhus, Henrik Permin, Leif P Andersen
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    ABSTRACT: To characterize and subgroup clinical strains of Campylobacter concisus isolated from patients with gastrointestinal disease. A total of 109 C. concisus isolates from 98 patients obtained between June 1997 and December 1998 were analysed using protein profiles, conventional biochemical tube tests, ApiCampy, and susceptibility patterns by Neosensitabs and E-test. Two groups were identified by using protein profiles. One resembled the ATCC 33237 type strain of oral origin, and a second group differing from it, particularly in the high molecular weight zone. Considerable diversity exists in the lower molecular range of the gels, also within assigned subgroups. Biochemical testing showed differences between the groups in the ability to reduce nitrate, ApiCampy testing also yielded differences between the two assigned groups, although reactions were highly heterogeneous. Resistance to erythromycin, ciprofloxacin, ampicillin, ceftriaxone and tetracycline occurred in 3%, 13%, 7%, 11% and 0% of the isolates when using Neosensitabs. The E-test yielded comparable results 7%, 5%, 0%, 2% and 3%, respectively. Results indicate that C. concisus can be assigned to two broad groups based on differences in protein profiles. No distinct phenotypic marker was identified. Susceptibility patterns are not suitable for discrimination between the two assigned groups. Further studies using a polyphasic approach including the application of genetic methods are needed to assess the complex taxonomy of this potential pathogen.
    European Journal of Gastroenterology & Hepatology 11/2005; 17(10):1019-24. · 1.92 Impact Factor

Publication Stats

2k Citations
425.17 Total Impact Points


  • 2012
    • Lithuanian University of Health Sciences
      Caunas, Kauno Apskritis, Lithuania
  • 1995–2012
    • Copenhagen University Hospital
      København, Capital Region, Denmark
    • Copenhagen University Hospital Gentofte
      Hellebæk, Capital Region, Denmark
  • 1996–2010
    • Glostrup Hospital
      • Department of Internal Medicine
      Glostrup, Capital Region, Denmark
  • 1995–2010
    • Rigshospitalet
      • • Department of Infection Control
      • • Department of Clinical Microbiology
      • • Department of Infectious Diseases
      Copenhagen, Capital Region, Denmark
  • 1992–2009
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 2005–2008
    • Kaunas University of Technology
      Caunas, Kauno Apskritis, Lithuania
  • 1992–2008
    • University of Copenhagen
      • Department of Clinical Microbiology
      København, Capital Region, Denmark
  • 1994–2007
    • Copenhagen University Hospital Hvidovre
      • • Department of Pathology
      • • Department of Infectious Diseases
      Hvidovre, Capital Region, Denmark
  • 1997–2005
    • Bispebjerg Hospital, Copenhagen University
      København, Capital Region, Denmark
  • 2003
    • Pasteur Institute of Iran (IPI)
      Teheran, Tehrān, Iran
  • 1989–2003
    • Hillerød Hospital
      Hillerød, Capital Region, Denmark
  • 2000–2002
    • Lund University
      Lund, Skåne, Sweden
  • 2001
    • Odense University Hospital
      Odense, South Denmark, Denmark
  • 1999–2000
    • Aalborg University Hospital
      • Department of Clinical Immunology
      Aalborg, Region North Jutland, Denmark
    • Statens Serum Institut
      København, Capital Region, Denmark
  • 1998
    • Næstved Hospital
      • Department of Medicine
      Нествед, Zealand, Denmark