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Biomedical subjects

M Tvede

Publications and source records attributed to M Tvede.

At least 19 recordsLinked to original sources
PubMed2006

Comparison in a laboratory model between the performance of a urinary closed system bag with double non-return valve and that of a single valve system.

BACKGROUND: Catheter-associated urinary tract infection is the most common nosocomial infection in clinical settings. For bacteria ascending to the bladder the most common route is the extraluminal, but the intraluminal route also plays a role. For this reason, we compared two urinary closed system bags (CSB), one with a double and the other with a single non-return valve (NRV), in a laboratory setting in order to establish their ability to prevent or delay the ascent of bacteria from the drainage bag to the bladder. PATIENTS AND METHODS: The tests were performed in two microbiological laboratories (Copenhagen (C), Denmark and Freiburg (F), Germany). These were blinded to each other. A urinary tract model using artificial urine was set up. Two sets of ten drainage bags each with a double NRV (CSB A), and two sets of ten drainage bags each with a single NRV (CSB B) were inoculated with Escherichia coli (F: ATCC 25922; C: clinical strain). Daily samples were taken from two drainage ports on each system - one above the NRV (Port I), the other above the top of the artificial bladder (Port II). Time till E. coli was detected at the drainage ports (time to positivity) was measured. Colonization of the 'bladder' was defined as time to positivity at Port II. RESULTS: No significant differences in time to positivity at Port I (median 9.0, range: 6-12 for CSB B vs median 9.5 days, range: 6-13 for CSB A) were observed between the two systems. However, substantial differences were seen between the two systems in time to positivity at Port II: Port II on the bladder model using CSB B became positive after a median of 14.0 days (range: 10-22), whereas Port II of the model using CSB A only became positive after 21.5 days (range: 13-24). This amounts to a highly significant difference of 7.5 days (p = 0.0001) in the mean. CONCLUSION: Under laboratory conditions, colonization of the 'bladder' was significantly delayed when the CSB with a double NRV was used in comparison to the results obtained from the single NRV-system. Clinical trials should be conducted to investigate whether the urinary CSB with the double NRV has the ability to prevent (or to delay the onset of) catheter-associated urinary tract infection.

Equipment Contamination↗
PubMed2005

Hydrophilic-coated catheters for intermittent catheterisation reduce urethral micro trauma: a prospective, randomised, participant-blinded, crossover study of three different types of catheters.

OBJECTIVE: To compare two hydrophilic-coated (SpeediCath and LoFric and one uncoated gel-lubricated catheter (InCare Advance Plus) concerning withdrawal friction force and urethral micro trauma. METHODS: 49 healthy male volunteers participated in this prospective, randomised, blinded, crossover study of three different bladder catheters. The withdrawal friction force was measured, and urine analysis of blood, nitrite and leucocytes, microbiological analysis of urine cultures and subjective evaluation of the catheters were performed. RESULTS: 40 participants completed the study and were included in the analysis. SpeediCath exerted a significantly lower mean withdrawal friction force and work than the gel-lubricated uncoated catheter, whereas LoFric exerted a significantly higher mean friction force than both of the other catheters. The hydrophilic catheters caused less microscopic haematuria and less pain than the gel-lubricated uncoated catheter. Furthermore, 93% of the participants preferred the hydrophilic catheters. CONCLUSION: Hydrophilic-coated catheters perform better than uncoated catheters with regard to haematuria and preference. SpeediCath, but not LoFric, exerts less withdrawal friction force than InCare Advance Plus.

Adult↗
PubMed2005

Patient education--a strategy for prevention of infections caused by permanent central venous catheters in patients with haematological malignancies: a randomized clinical trial.

A functioning tunnelled central venous catheter (CVC) is a crucial device for patients with haematological malignancies receiving high-dose intravenous chemotherapy. Despite the advantages, CVC infections are a major cause of sepsis and prolonged hospital stay. This study investigated the impact of patient education regarding provision of their own catheter care on the frequency of CVC-related infections (CRIs) and was conducted at a specialized haematological unit at the University Hospital of Copenhagen Rigshospitalet. From May to September 2002, 82 patients fitted with tunnelled double-lumen Hickman catheters were randomized consecutively. The intervention group (42 participants) received individualized training and supervision by a clinical nurse specialist, with the aim of becoming independently responsible for their own catheter care. The control group (40 participants) followed the standard CVC procedures carried out by nurses inside and outside the central hospital. A significant reduction in CRIs was found in the intervention group, with a >50% reduction in the incidence rate of CRIs. We conclude that systematic individualized, supervised patient education is able to reduce catheter-related infections.

Adolescent↗
PubMed2003

A European survey of diagnostic methods and testing protocols for Clostridium difficile.

OBJECTIVE: To conduct a survey of the methods used in clinical microbiology laboratories in Europe to diagnose infection with Clostridium difficile. METHODS: A questionnaire was devised and sent to a co-ordinating member of the Study Group in each of eight European countries. This co-ordinator was in charge of forwarding the questionnaire to hospital laboratories arbitrarily selected. The number of laboratories in each country was determined on the basis of one laboratory for 10,000 beds of hospitalization. This questionnaire covered different aspects pertaining to Clostridium difficile associated to diarrhea (CDAD) diagnosis such as circumstances of request, criteria used for undertaking C. difficile investigations, methods used for the diagnosis, etc. RESULTS: A total of 212 questionnaires were completed and submitted for analysis: 87.7% of laboratories reported routinely performing C. difficile diagnostic tests. Methods used included toxin detection (93%), culture (55%), and glutamate dehydrogenase (GDH) detection (5.9%). Among the laboratories detecting toxins, different enzyme immunoassays (EIA) and cytotoxicity assays were used in 79% and 17.3% of cases, respectively. Among the different strategies reported, 4.8% were considered suboptimal for the diagnosis of C. difficile infections, but marked discrepancies could be observed between countries. The overall incidence (median) of CDAD was estimated at 1.1 for 1,000 patient admissions. CONCLUSION: The results of this study suggest marked discrepancies between laboratories and also between countries regarding the criteria by which C. difficile is investigated for, and the methods and the strategies that are used for the diagnosis of C. difficile. These discrepancies could be explained by the lack of clear guidelines for C. difficile diagnosis in each country, and by the importance that physicians attach to C. difficile. Precise guidelines for C. difficile diagnosis would be the first step to make possible accurate comparison of the incidence and the epidemiology of CDAD from one hospital to another or from one country to another.

Bacterial Proteins↗
PubMed2001

[Antibiotic resistance of E coli isolated from healthy persons].

INTRODUCTION: The aim of the study was to determine the antibiotic susceptibility of E. coli isolates in stools from healthy Danes. METHODS: Sixty-nine persons from Copenhagen participated in the study. Three faecal samples from each participant were examined by culture for each of three periods. E. coli was isolated selectively and tested for sensitivity against sulfamethizole, trimethoprim, the combination of sulfamethizole and trimethoprim, ampicillin, mecillinam, cefuroxime, nitrofurantoin, and ciprofloxacin. RESULTS: Altogether, 184 strains of E. coli were isolated from 66 of the 69 persons. Fifty-eight (31.5%) of the strains isolated from 30 persons (43.5%) were resistant to sulfamethizole, 32 (17.4%) strains isolated from 18 persons (26.1%) were resistant to trimethoprim, 31 (16.8%) strains isolated from 17 persons (24.6%) were resistant to trimethoprim + sulfamethizole, 57 (31%) strains from 31 persons (44.9%) were resistant to ampicillin, 29 (15.8%) of the strains from 24 persons (34.8%) were resistant to nitrofurantoin, two (1.1%) strains from two persons (2.9%) were resistant to cefuroxime, whereas none of the strains was resistant to mecillinam and ciprofloxacin. DISCUSSION: The high prevalence of resistance to sulfamethizole, ampicillin, trimethoprim, and nitrofurantoin is surprising, as none of the persons had been treated with antibiotics, but it may reflect the widespread use of antibiotics in animals for food production. The consequences of the results for empiric antibiotic treatment of, for instance, urinary tract infection are discussed.

Adult↗
PubMed2000

Impact on human intestinal microflora of an Enterococcus faecium probiotic and vancomycin.

The aims of this study were to evaluate the impact of a fermented milk product containing viable Enterococcus faecium on human intestinal microflora and to evaluate any risk of development of vancomycin-resistant enterococci (VRE). Twenty Danish and 20 Swedish healthy volunteers were given 150 ml of the fermented milk product once daily, equivalent to a daily dose of 4.5 x 10(9) to 7.5 x 10(9) CFU E. faecium, for 10 d. Half of the volunteers also received 125 mg vancomycin orally q.i.d. for 10 d. Faecal samples were collected on day 0 before intake, on day 10 directly after end of intake and on day 31, 3 weeks after the end of the experiment. There was a significant increase in the total number of enterococci on day 10 (p < 0.01) in the group receiving only the E. faecium supplement, but 3 weeks later the level was as before intake. In the vancomycin group, the total number of enterococci was reduced on day 10 (p < 0.01) but had increased on day 31 (p < 0.01) in relation to day 0. In none of the Swedish and 4 of the Danish volunteers, VRE were sporadically detected, but without relation to intake of the probiotic or vancomycin. In healthy young Danish individuals the VRE carrier rate tended to be higher than previously found.

Adult↗
PubMed2000

Retrospectively sampled time-to-pregnancy data may make age-decreasing fecundity look increasing. European Infertility and Subfecundity Study Group.

The retrospective study based on pregnancy samples is the most commonly used method for studying time to pregnancy. Using a simple Monte Carlo simulation, this note focuses on a particular selection bias problem associated with this design: even if each woman's fecundity decreases with age, estimation of the effect of age may show the opposite trend. We recommend exercising increased caution in interpreting findings from pregnancy-based time-to-pregnancy studies.

Adult↗
PubMed1999

Screening of probiotic activities of forty-seven strains of Lactobacillus spp. by in vitro techniques and evaluation of the colonization ability of five selected strains in humans.

The probiotic potential of 47 selected strains of Lactobacillus spp. was investigated. The strains were examined for resistance to pH 2.5 and 0.3% oxgall, adhesion to Caco-2 cells, and antimicrobial activities against enteric pathogenic bacteria in model systems. From the results obtained in vitro, five strains, Lactobacillus rhamnosus 19070-2, L. reuteri DSM 12246, L. rhamnosus LGG, L. delbrueckii subsp. lactis CHCC 2329, and L. casei subsp. alactus CHCC 3137, were selected for in vivo studies. The daily consumption by 12 healthy volunteers of two doses of 10(10) freeze-dried bacteria of the selected strains for 18 days was followed by a washout period of 17 days. Fecal samples were taken at days 0 and 18 and during the washout period at days 5 and 11. Lactobacillus isolates were initially identified by API 50CHL and internal transcribed spacer PCR, and their identities were confirmed by restriction enzyme analysis in combination with pulsed-field gel electrophoresis. Among the tested strains, L. rhamnosus 19070-2, L. reuteri DSM 12246, and L. rhamnosus LGG were identified most frequently in fecal samples; they were found in 10, 8, and 7 of the 12 samples tested during the intervention period, respectively, whereas reisolations were less frequent in the washout period. The bacteria were reisolated in concentrations from 10(5) to 10(8) cells/g of feces. Survival and reisolation of the bacteria in vivo appeared to be linked to pH tolerance, adhesion, and antimicrobial properties in vitro.

Administration, Oral↗
PubMed1998

Bacterial endocarditis at a tertiary hospital--how do we improve diagnosis and delay of treatment? A retrospective study of 140 patients.

During a period of 3.5 years, endocarditis was suspected in 151 patients admitted to Rigshospitalet. 140 were available for this study. In 59 of the 140 patients, the diagnosis was confirmed, and 36 had positive blood cultures. Echocardiographic findings compatible with the diagnosis were present in 92% of the 59 cases. The most common causes of endocarditis were Staphylococcus aureus and viridans streptococci. Patients with endocarditis caused by S. aureus had significantly (p = 0.002) more embolic episodes compared to patients having endocarditis caused by the viridans streptococci. The diagnosis was established at a mean of 3-4 weeks after the onset of symptoms and 2 weeks after admission to hospital. In order to minimize diagnostic delay, the following aspects may be important: (1) earlier detection of endocarditis among physicians examining patients at risk; (2) educating patients with cardiac disease and cardiac valve prosthesis; (3) earlier antibiotic therapy, and (4) developing further diagnostics for endocarditis.

Anti-Bacterial Agents↗
PubMed1997

Excretion of ciprofloxacin in sweat and multiresistant Staphylococcus epidermidis.

BACKGROUND: Staphylococcus epidermidis develops resistance to ciprofloxacin rapidly. That this antibiotic is excreted in apocrine and eccrine sweat of healthy individuals might be the reason for the development of such resistance. We assessed whether S epidermidis isolated from the axilla and nasal flora of healthy people could develop resistance to ciprofloxacin after a 1-week course of this antibiotic. METHODS: The concentration of ciprofloxacin in sweat was measured in seven volunteers after oral administration of 750 mg ciprofloxacin twice daily for 7 days, and the development of resistance in S epidermidis from axilla and nostrils was monitored during and 2 months after the treatment. Genotyping of S epidermidis was done by restriction fragment length polymorphism. FINDINGS: The mean concentration of ciprofloxacin in sweat increased during the 7 days of treatment-from 2.2 micrograms/mL 2.5 h after the first tablet to 2.5 micrograms/mL after the fifth tablet, and 5.5 micrograms/mL after the 13th tablet. All persons harboured susceptible S epidermidis (minimal inhibitory concentration [MIC] 0.25 microgram/mL) in axilla and nostrils before treatment. Four resistant strains were detected, two intermediate-level (MIC 4-12 micrograms/mL) and two high-level (MIC > 32 micrograms/mL). Three of these strains were found in all the participants, and a ciprofloxacin-sensitive variant of one of the high-level resistant strains was also found before the start of the treatment. The high-level resistant strains were also resistant to methicillin, erythromycin, gentamicin, sulphonamide, and trimethoprim. A mean of 2.7 days after the start of the treatment, development of ciprofloxacin resistance was detected in S epidermidis from the axilla of all persons, compared with 11 days for the appearance of resistant S epidermidis in nostrils. The resistant strains persisted for an average of 37 and 39 days in axilla and nostrils, respectively, after the end of the treatment. INTERPRETATION: The rapid development of resistance to ciprofloxacin due to excretion of this drug into the sweat might be involved in the development of multiresistant S epidermidis and possibly other skin bacteria in hospitals and in communities with high use of ciprofloxacin or related drugs.

Administration, Oral↗
PubMed1997

Infective endocarditis, 1984 through 1993: a clinical and microbiological survey.

OBJECTIVES: To characterize the epidemiology and the clinical and microbiological spectrum of infective endocarditis in a Danish population. DESIGN: A retrospective review. SETTING: All episodes hospitalized of infective endocarditis from 1984 to 1993 in Viborg County were reviewed. The county is served by one general and four local hospitals. SUBJECTS: One hundred and nine episodes of suspected infective endocarditis with 62 episodes in 59 patients fulfilling the diagnostic criteria by von Reyn. RESULTS: An overall incidence of 27 episodes per million per year was found. The incidence was 17.4 episodes per million per year in the first part of the decade and 36.5 episodes per million per year in the second part (P < 0.001). Microscopic haematuria was found in 70.2% of the patients with infective endocarditis, compared to 16.7% of the patients in whom the diagnosis was rejected (P < 0.01). Staphylococcus aureus was found in 38.9%, non-beta-haemolytic streptococci in 24.1% and Enterococcus faecalis in 16.7%. The overall mortality was 35.5%. The mortality decreased significantly from 50.0% in the first part of the decade to 28.6% in the second part (P < 0.01). The mortality was 23.1% in patients in whom the diagnosis was established whilst they were alive. This finding was significantly lower than the overall mortality (P < 0.05). CONCLUSION: The incidence of infective endocarditis increased during the decade. The frequency of non-beta-haemolytic streptococci was lower than normally reported. Mortality is still high, with the main mortality within the first week in hospital, which stresses the importance of early case detection and treatment.

Causality↗
PubMed1996

Immunological properties of meningococcal lipopolysaccharide from serogroups A, B & C.

The aim of the study was to measure and compare the oxidative burst, chemotaxis and cytokine production of human white blood cells, stimulated with meningococcal lipopolysaccharides (LPS) extracted from three different serogroups (A, B and C) of Neisseria meningitidis, and to evaluate whether convalescent sera from patients with meningococcal disease could modify cell stimulation of LPS. All three preparations of LPS from groups A, B and C were tested using the Limulus amoebocyte lysate assay (LAL), and the KDO concentrations of the LPS extracts were measured. Equivalent amounts of biologically active LPS, judged by LAL, and LPS with the same KDO concentration were assayed. IL-1alpha, IL-1beta, IL-6 and TNF-alpha production was stimulated by all three LPS preparations. All three preparations stimulated oxidative burst in monocytes (MNC). Only group A LPS stimulated neutrophil chemotaxis, while none of the three LPS stimulated superoxide production. Pooled convalescent sera from five patients with meningococcal disease suppressed the activity of neutrophils stimulated with LPS from groups B and C (p<0.05, Mann-Whitney U-test).

Cells, Cultured↗