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H Erlendsdóttir

Publications and source records attributed to H Erlendsdóttir.

12 recordsLinked to original sources
PubMed2005

Nationwide study of recurrent invasive pneumococcal infections in a population with a low prevalence of human immunodeficiency virus infection.

Recurrent invasive infections caused by Streptococcus pneumoniae are rare, and often considered to be indicative of serious underlying illness. However, the prevalence of this problem, and the relevance of specific predisposing conditions, can be hard to assess, since many of the studies are based on specific risk groups. A population-based study of recurrent invasive pneumococcal disease in Iceland during the 30-year period 1975-2004 was performed. Clinical information, including mortality and vaccine use, was analysed retrospectively. Invasive pneumococcal isolates were serotyped and susceptibility testing was performed. During this period, 36 (4.4%) of 819 patients who survived an initial infection experienced recurrence, with a median time between episodes of 9.7 months. Pneumonia with bacteraemia was the most common clinical diagnosis (48% of cases), followed by bacteraemia without a clear focus (21%) and meningitis (13%). Most (94%) of the patients had identifiable predisposing conditions, most commonly, multiple myeloma in adults, and antibody deficiencies in children. Compared with children, adults were more likely to present with pneumonia (65% vs. 18%; p 0.0001). No significant change in the 30-day mortality rate was observed during the three decades of the study. Only 26% of eligible patients received pneumococcal vaccination. Patients with recurrent invasive pneumococcal disease should be investigated thoroughly for underlying diseases. Greater use of pneumococcal vaccines should be encouraged among high-risk patients. More effective preventive and therapeutic measures are needed to improve outcomes.

Aged↗
PubMed2004

The improved survival of experimental animals fed with fish oil is suppressed by a leukotriene inhibitor.

Fish oil is believed to alter the immune response and improve survival after infections in experimental animals. This effect may be due to altered production of the leukotrienes (LT). We, therefore, performed a study in order to evaluate whether the effect of fish oil on the immune response of experimental animals is mediated through altered production of the LT. Female NMRI mice in four groups were fed with fish oil, fish oil with 5-lipoxygenase (5-LO) inhibitor (Zileuton, Abbott Laboratories, Chicago, IL, USA), corn oil or corn oil with 5-LO inhibitor. After 6 weeks, the mice were infected with Klebsiella pneumoniae and the survival was monitored. The experiment was performed twice. Analysis was performed mainly on data pooled from both experiments. The survival of the groups fed with fish oil was increased, compared to that of all the other groups and when compared to the groups fed with fish oil with 5-LO inhibitor (log-rank test) the difference was significant (P = 0.007). It has been postulated that the effect of fish oil on the immune system is mediated through altered production of LT. In our study, blocking of the production of the LT eliminated the beneficial effects of fish oil. Our results are in concord with the hypothesis that the effect of fish oil is, at least partly, mediated through altered production of LT.

Animals↗
PubMed2001

[The effect of dietary fish oil on bacterial growth in vivo.].

OBJECTIVE: Epidemiological studies have indicated that high intake of w-3 fatty acids influence various diseases such as cardiovascular diseases and autoimmune disorders. These fatty acids are essential in the diet since the body can not form them de novo. Fish oil is rich in w-3 fatty acids but the w-3 content of vegetable oil is low. The research group has shown increased survival of mice fed cod liver oil enriched diet versus mice fed corn oil enriched diet when infected with Klebsiella pneumoniae intramuscularly. In the present study we investigated the effect of dietary fish oil on bacterial growth in vivo. MATERIAL AND METHODS: Mice were fed fish oil enriched diet and a control group was fed corn oil enriched diet for six weeks and then the mice were infected with Klebsiella pneumoniae intramuscularly. The mice were sacrificed at various time intervals and bacteria were counted in blood and in the infected muscle. RESULTS: The bacteria count in blood and tissue was not significantly different between the two groups although a trend was noted towards more growth in the control group. CONCLUSIONS: We conclude that fish oil does not significantly affect bacterial growth in vivo. Hopefully, future research will reveal the pathophysiological effect of fish oil.

English Abstract↗
PubMed2001

[Fungemia and other invasive fungal infections in Icelandic children. A nationwide study.].

INTRODUCTION: Invasive fungal infections are increasing in incidence. Among those who are at increased risk of fungal blood stream infections (fungemia) and disseminated fungal infections are premature infants and immunosuppressed children. These infections are associated with high morbidity and mortality. Invasive fungal infections have not yet been studied in Iceland. MATERIAL AND METHODS: We studied all cases of fungemia and/or disseminated fungal infections in Icelandic children (16 years) during a 20 year period. Histopathology reports and autopsies were reviewed. Information on predisposing factors, symptoms, treatment and outcome was collected. All obtainable fungal blood stream isolates were subcultured and their susceptibility to common antifungals determined. RESULTS: In the 20 year period from 1980-1999, 19 episodes of invasive fungal infections were diagnosed in 18 infants and children in Iceland. Twelve episodes of fungemia occured in 11 children and the nationwide annual incidence increased from 0.28 to 1.90 cases/100,000/year (p=0.037) during the study period. Half of the children were premature infants. All patients had a central venous catheter at the time of blood culture and most had received intravenous antibiotics or corticosteroids. Candida albicans was the most commonly isolated species (nine of 12 episodes, 75%). In addition to patients with fungemia, three children were diagnosed with disseminated fungal infection by histology or autopsy. Two cases of fungal meningitis, without fungemia, were identified. Furthermore, two children had invasive infections with Aspergillus fumigatus and both patients survived. Three children (3/16; 19%) with invasive Candida-infections died. CONCLUSIONS: In this study of invasive fungal infections among Icelandic children we demonstrate that the incidence of fungemia has risen significantly in the past 20 years. Diagnosis of invasive fungal infections can be complicated and negative blood cultures do not exclude disseminated infection. Given the high attributable mortality, timely diagnosis and aggressive treatment is extremely important.

English Abstract↗
PubMed1998

Characteristics and dynamics of bacterial populations during postantibiotic effect determined by flow cytometry.

Changes in bacterial ultrastructure after antibiotic exposure and during the postantibiotic effect (PAE) have been demonstrated by electron microscopy (EM). However, EM is qualitative and subject to individual interpretation. In contrast, flow cytometry gives qualitative and quantitative information. The sizes and nucleic acid contents of Escherichia coli and Pseudomonas aeruginosa were studied during antimicrobial exposure as well as during the PAE period by staining the organisms with propidium iodide and analyzing them with flow cytometry and fluorescence microscopy. The effects of ampicillin, ceftriaxone, ciprofloxacin, gentamicin, and rifampin were studied for E. coli, whereas for P. aeruginosa imipenem and ciprofloxacin were investigated. After exposure of E. coli to ampicillin, ceftriaxone, and ciprofloxacin, filamentous organisms were observed by fluorescence microscopy. These changes in morphology were reflected by increased forward light scatter (FSC) and nucleic acid content as measured by flow cytometry. For the beta-lactams the extent of filamentation increased in a dose-dependent manner after drug removal, resulting in formation of distinct subpopulations of bacteria. These changes peaked at 20 to 35 min, and bacteria returned to normal after 90 min after drug removal. In contrast, the subpopulations induced by ciprofloxacin did not return to normal until > 180 min after the end of the classically defined PAE. Rifampin resulted in formation of small organisms with low FSC, whereas no distinctive characteristics were noted after gentamicin exposure. For P. aeruginosa an identifiable subpopulation of large globoid cells and increased nucleic acid content was detected after exposure to imipenem. These changes persisted past the PAE, as defined by viability counting. Swollen organisms with increased FSC were detected after ciprofloxacin exposure, even persisting during bacterial growth. In summary, for beta-lactam antibiotics and ciprofloxacin, the PAE is characterized by dynamic formation of enlarged cell populations of increased nucleic acid content, whereas rifampin induces a decrease in size and nucleic acid content in the organisms. Flow cytometry is an ideal method for future studies of bacterial phenotypic characteristics during the PAE.

Anti-Bacterial Agents↗
PubMed1997

Acute bacterial meningitis in adults. A 20-year overview.

BACKGROUND: Most clinical overviews of acute bacterial meningitis have either focused on children or all age groups combined, although the disease poses serious problems in the adult population. OBJECTIVE: To study the clinical and microbiological features of adult bacterial meningitis in Iceland, as a representative of the average European or North American community. PATIENTS AND METHODS: Data on a total of 132 cases in 127 patients (age, > or = 16 years) who were diagnosed as having acute bacterial meningitis in Iceland during the years 1975 to 1994 were collected from patient and laboratory records. Complete hospital records were found for 119 of the 132 cases identified. RESULTS: The annual incidence was 1.7/100,000 to 7.2/ 100,000 inhabitants (mean, 3.8/100,000). The most common causative organisms were Neisseria meningitidis (56%), Streptococcus pneumoniae (20%), Listeria monocytogenes (6%), and Haemophilus influenzae (5%). Neisseria meningitidis caused 93% of the infections in the 16- to 20-year-old age group, but it caused only 25% of the infections in patients aged 45 years or older. Listeria monocytogenes caused 14% of these cases. Cases of nosocomial and recurrent meningitis were rare. A significant underlying illness or condition was present in 39% of the patients. The mean mortality was 19.7%, and it did not change during the study period. CONCLUSIONS: In a study that involved all adult patients with bacterial meningitis in a single country for 2 decades, meningococci and pneumococci were the most frequent causative agents. However, meningococci were responsible for only one fourth of the cases among adult patients aged 45 years or older, most of these cases were caused by pneumococci and Listeria. Despite modern medical developments, approximately 20% of adult patients with bacterial meningitis died.

Acute Disease↗
PubMed1995

Different patterns of bacterial DNA synthesis during postantibiotic effect.

Studies on bacterial metabolism during the postantibiotic effect (PAE) period are limited but might provide insight into the nature of the PAE. We evaluated the rate of DNA synthesis in bacteria during the PAE period after a 1-h exposure of organisms in the logarithmic growth phase to various antibiotics. Staphylococcus aureus ATCC 25923 was exposed to vancomycin, dicloxacillin, rifampin, and ciprofloxacin; Escherichia coli ATCC 25922 was exposed to gentamicin, tobramycin, rifampin, imipenem, and ciprofloxacin; and Pseudomonas aeruginosa ATCC 25783 was exposed to imipenem, tobramycin, and ciprofloxacin. DNA synthesis was determined by measuring the rate of [3H]thymidine incorporation in S. aureus and E. coli and [3H]adenine incorporation in P. aeruginosa. DNA synthesis in S. aureus was suppressed during the PAE phase with vancomycin, dicloxacillin, and rifampin, it was suppressed in E. coli with rifampin, and it was suppressed in P. aeruginosa after exposure to tobramycin. Conversely, DNA synthesis was relatively enhanced in the gram-negative bacilli after exposure to imipenem and in all three species after exposure to ciprofloxacin. However, DNA synthesis in E. coli was only minimally affected after exposure to tobramycin and gentamicin. The differences in DNA synthesis observed after exposure to various antimicrobial agents suggest multiple mechanisms for the PAE.

Anti-Bacterial Agents↗
PubMed1990

Metabolic and ultrastructural effects induced by ciprofloxacin in Staphylococcus aureus during the postantibiotic effect (PAE) phase.

The new quinolone antibacterial agents have been found to produce a postantibiotic effect (PAE) of 1-4 h in bacteria but the underlying mechanism is still unknown. After exposure to ciprofloxacin in concentrations of 1-16 x MIC for 1 hr the DNA synthesis in S. aureus ATCC 25923 was investigated during the PAE. Ultrastructure was also investigated by electron microscopy after exposure to a concentration of 2 x MIC. The rate of DNA synthesis per organism (measured as CPM/cfu/ml) increased progressively up to a maximum value at 1 1/2 h after drug removal. The maximal 3H-thymidine incorporation per organism at this moment correlated directly with the duration of the PAE. Bacterial swelling with scarcity and vacuole-formation of the cytoplasm characterized the majority of the staphylococci during the PAE. The physiological importance of the increased DNA synthesis is unknown, but the increased metabolic activity, coincident with increased duration of the PAE, suggests a possible common mechanism.

Ciprofloxacin↗
PubMed1990

The postantibiotic effect induced by antimicrobial combinations.

Antimicrobial combinations are frequently needed for the successful treatment of serious infections. Generally, the same dosing schedules are employed irrespective of whether the drugs are used singly or in combination. A postantibiotic effect (PAE) has been described for all antibiotics used singly against Gram-positive cocci, but only for non-beta-lactams against Gram-negative bacilli with the exception of carbapenems against Pseudomonas aeruginosa. The major clinical relevance of the PAE pertains to its impact on antimicrobial dosing, where agents inducing a long PAE may be administered with longer dosing intervals than currently employed, without loss of efficacy. The purpose of this study was to examine whether PAEs induced by drug combinations differed from the PAEs induced by the drugs alone, and whether a pattern of synergism, addition or antagonism could be defined in this regard. The study organisms, 7 strains of Staphylococcus aureus, 4 strains of Escherichia coli, 4 strains of Klebsiella pneumoniae and 6 strains of Ps. aeruginosa, were exposed to several beta-lactams, aminoglycosides, rifampin and ciprofloxacin singly and in combination. The antimicrobial combinations used against S. aureus affected the PAE in either an additive or an indifferent manner when compared to the PAEs induced by the drugs as single agents. Enhancement of PAEs against Gram-negative bacilli was primarily dependent on the ability of each individual drug to induce a PAE. Thus, for a combination of drugs where both agents induced a PAE individually, the final PAE was a rough mathematical sum of the individual PAEs (addition). When only one of the agents induced a PAE, the final result was similar to the PAE of that particular drug (indifference). Ciprofloxacin seemed to be an exception to this rule, since it did not increase the PAE of a PAE producing drug, despite exhibiting a PAE itself. Rifampin was unique in that it prolonged the PAE in a marked synergistic fashion, when employed with one or more other PAE-producing agents. Further studies in vivo are clearly needed to confirm these observations, but they could have significant impact on the design of dosing regimens for antimicrobial combinations.

Anti-Bacterial Agents↗
PubMed1986

Pharmacokinetics of dicloxacillin in serum and aortic wall during aneurysmal surgery.

Twenty-one patients undergoing elective surgery for abdominal aortic aneurysm were randomly assigned to receive 2 grams of dicloxacillin as an intravenous infusion either at the induction of anaesthesia, 3 hours or approximately 6 hours before surgery. Samples from serum and aortic tissue were simultaneously obtained so that antibiotic levels could be compared as a function of time. High concentrations of dicloxacillin in serum and aortic tissue were present already shortly after infusion and active levels were maintained in aortic tissue for approximately six hours. The kinetics of dicloxacillin was similar in serum and aortic tissue. These results support the need for antibiotic administration shortly before surgery to ensure adequate tissue levels of antibiotics.

Aged↗
PubMedDate not supplied

Ultrastructural alterations of bacteria during the postantibiotic effect.

Ultrastructural alterations of Staphylococcus aureus and Pseudomonas aeruginosa were examined during the postantibiotic effect (PAE) with transmission electron microscopy. After exposure to dicloxacillin the staphylococci were characterized by an increase in the number of crosswalls, rifampin produced thickening of the cell wall, but only minimal changes were induced by gentamicin. Intracellular electrondense aggregates were observed in P. aeruginosa after exposure to imipenem, tobramycin and ciprofloxacin, and imipenem caused globoid cell formations. These alterations were not uniform in every organism, but they correlated well with the duration of the PAE determined by viable counts.

Anti-Bacterial Agents↗