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E T Jensen

Publications and source records attributed to E T Jensen.

At least 19 recordsLinked to original sources
PubMed2006

Control of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak in a day-care institution.

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.

Adult↗
PubMed2005

Near-UV photodissociation of oriented CH3I adsorbed on Cu(110)-I.

Methyl iodide adsorbed on a Cu(110)-I surface has been found to be highly orientationally ordered. We have exploited this orientation to select different CH(3)I excited states for photodissociation by using polarized near-UV light at wavelengths of 308, 248, and 222 nm. Using p-polarized light at all three wavelengths, we find that dissociation proceeds largely via the (3)Q(0) state, consistent with the picture from gas-phase photolysis. In contrast, using s-polarized light we find contributions from the (3)Q(1) state at lambda=308 nm, the (1)Q(1) state at lambda=248 nm, and the (E,1) state at lambda=222 nm-the latter being a state that has not been implicated in gas-phase studies of CH(3)I A-band photolysis. We also note the contribution to surface photodissociation from low-energy photoelectrons causing dissociative electron attachment to adsorbed CH(3)I and have identified the promotion of direct photodissociation pathways during lambda=308 nm photolysis.

Journal Article↗
PubMed2001

Prevalence of and detection of resistance to ampicillin and other beta-lactam antibiotics in Haemophilus influenzae in Denmark.

The susceptibility of Haemophilus influenzae to penicillin V and G, ampicillin and cefuroxime was investigated by MIC, disc and tablet diffusion methods, using chocolate agar as test medium, to determine the prevalence of ampicillin-resistant isolates and the optimal method for their detection. Eighty-six isolates were clinical isolates collected prospectively from July to September 1998 and 22 isolates were clinical isolates with decreased susceptibility to ampicillin previously referred to the reference laboratory. Eighty-seven isolates were ampicillin-susceptible and 16 were ampicillin-resistant. Thirteen produced beta-lactamases. Among the consecutive isolates 12.8% were resistant. With each of the Rosco Neo-sensitabs containing penicillin G, 2.5 microg ampicillin and 33 microg ampicillin, 3 very major errors occurred (resistant isolates misinterpreted as susceptible) and 5-13 major errors (susceptible isolates misinterpreted as resistant). The AB biodisk containing ampicillin (10 microg) was superior to the penicillin V and G discs, i.e. only 1 very major error occurred and major and minor errors were infrequent. The cefuroxime disc identified 4/8 beta-lactamase-negative ampicillin-resistant isolates. Thus, for susceptibility testing with chocolate agar as test medium, the use of an inoculum of 10(5) colony-forming units, 10 microg ampicillin discs and interpretative zone diameters of > or = 28 mm indicating susceptibility and < or = 25 mm indicating resistance was found to produce reliable identification of ampicillin-resistant isolates of H. influenzae.

Ampicillin↗
PubMed1997

Epidemiology of Pseudomonas aeruginosa in cystic fibrosis and the possible role of contamination by dental equipment.

Cystic fibrosis (CF) patients often suffer from Pseudomonas aeruginosa lung infection yet the source of this organism is not known. In order to determine whether CF patients might be contaminated with P. aeruginosa from dental equipment, a total of 103 water samples from 25 dental sessions in Frederiksberg Municipal Oral Health Care Service were examined. Three samples (2.9%) were positive for P. aeruginosa. Three hundred and twenty-seven water samples from 82 dental sessions from various other Municipal Oral Health Services in Denmark, attended by CF patients, were also examined. Eighteen of 327 samples (5.5%) from nine sessions (11%) were positive for P. aeruginosa. In one case, genotypically identical (RFLP, pulsed-field gel electrophoresis) P. aeruginosa strains were found both in water from the dental equipment and in the CF patients sputum. This indicates a small risk for acquiring P. aeruginosa from dental sessions, which is however equal to the yearly 'natural background' incidence (1-2%) of acquisition of P. aeruginosa in our CF centre.

Case-Control Studies↗
PubMed1995

High levels of complement-activation capacity in sera from patients with cystic fibrosis correlate with high levels of IgG3 antibodies to Pseudomonas aeruginosa antigens and poor lung function.

Heat-stable opsonins from sera of cystic fibrosis (CF) patients were investigated for their ability to activate complement. Complement activation by Pseudomonas aeruginosa after opsonization with patient serum was examined in a complement-consumption assay. Absorption of patients' sera with formalin-treated and boiled bacteria removed specific antibodies and the complement activation decreased. We found a positive correlation between serum complement-activation ability and IgG3 antibody levels to lipopolysaccharide (LPS), alginate, and a crude mixture of P. aeruginosa antigens (sonicate) in a group of patients with high levels of anti-Pseudomonas precipitins. In the same group of patients a significant negative correlation was found between complement activation and lung function. Eighteen patients have been followed longitudinally with serum samples covering the pre-infection, the early, and the late stages of chronic infection. Patients with poor lung function showed significantly higher levels of complement-activation capacity. We conclude that patients with high levels of specific IgG3 antibodies are able to induce a high level of complement activation and then develop more aggressive pulmonary tissue damage, probably secondary to local immune complex formation.

Adolescent↗
PubMed1994

[Biofilm, foreign bodies and chronic infections].

Most bacteria occur in the environment as sessile cells adhering to a surface, whereas a minority exists as free floating (planktonic) cells. Biofilms consist of microcolonies embedded in a polysaccharide matrix produced by the bacteria. This polysaccharide slime protects the bacteria against hostile environmental factors. Planktonic daughter cells are liberated from the surface of biofilms and may colonize new surfaces and subsequently produce new biofilms. Biofilms are often consortia of several different bacterial species. The normal microflora on the skin or on the mucous membranes in the human body occurs as a biofilm, which is removed by the shedding of old cells and by the excretion of mucus. Subsequently new cells and new mucus are colonized by biofilm forming bacteria without giving rise to any symptoms. When body surfaces with a normally occurring microflora (A) are connected by means of an implanted foreign body with body surfaces or tissue compartments without a microflora (B) e.g. bronchi, gall bladder, peritoneum, veins, then a translocation of the normal microflora from (A) to (B) may easily occur leading to acute infection, formation of new biofilms on the implanted foreign body and induction of inflammation in the environment of this biofilm. Chronic bacterial infections are frequently caused by biofilm producing bacteria and the pathogenesis of the tissue damage is dominated by a persistent immune complex mediated inflammation. Bacteria growing in biofilms cannot be eradicated by antibiotics and biofilms resist the immunological and non-specific defence mechanisms of the body.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1994

[Relation between cervical conization, microbial colonization and threatening preterm labor].

UNLABELLED: The relationship between prior cervical conization, the cervical microbial colonization and threatening preterm delivery was investigated in 35 women with preterm premature rupture of the membranes (PPROM), 38 women with idiopathic preterm labor and 75 normal pregnant women at 26-34 weeks of gestation. Prior cervical conization occurred with a significantly higher frequency in PPROM patients than in patients with preterm labor (p < 0.01) and normal pregnant women (p < 0.001). The prevalence of lactobacilli was lower in patients with PPROM than in patients with preterm labor (p < 0.05) and control patients (p = 0.05)--and lower in patients with prior cervical conization than in patients without prior conization (p < 0.05). All other microorganisms occurred with the same frequencies in all groups. CONCLUSIONS: Prior conization was associated with PPROM. Women with prior conization and women with PPROM had a reduced prevalence of lactobacilli in the cervix. The "absence" of lactobacilli may indicate changes in the cervical microflora, which could be of importance for PPROM.

Adult↗
PubMed1994

Correlation between specific IgG subclass antibodies to Pseudomonas aeruginosa and opsonic activity in serum from patients with cystic fibrosis.

Heat-stable opsonins from sera of patients with cystic fibrosis (CF) non-CF patients with chronic Pseudomonas aeruginosa infection, healthy children, and adults were investigated for their ability to promote phagocytosis of 35S-labeled P. aeruginosa by human polymorphonuclear neutrophils. Healthy children had significantly lower levels of opsonic activity than adults. Sera from patients with CF without chronic P. aeruginosa lung infection showed significantly higher levels of opsonic activity compared to healthy children. Sera from patients with CF in the early stage of chronic infection had similar opsonic activity as non-CF patients with chronic infection. Sera from patients with CF in the late stage of chronic infection had higher opsonic activity than other infected patients, but not different from adult controls. An inverse correlation was found between levels of specific antibodies to P. aeruginosa and opsonic activity in the group of patients in a late stage of infection. An inverse correlation was also found between levels of IgG1 and IgG3 to P. aeruginosa St-Ag and opsonic activity during the late stage of infection. Infection with P. aeruginosa in CF did not induce significantly increased opsonic activity. It seems that antibodies to P. aeruginosa may have inhibitory opsonic activity.

Adult↗
PubMed1994

Uro-genital microbial colonization and threatening preterm delivery.

OBJECTIVE: To examine whether there is a relationship between the uro-genital microbial colonization and threatening preterm delivery. STUDY DESIGN: The microflora in the urine and endocervix was studied in 43 women with preterm labor, 45 women with preterm premature rupture of the membranes (PPROM) and 80 normal pregnant women at 26-34 weeks of gestation. Amniotic fluid was examined in 20 of the patients with preterm labor. Data were analyzed by Fisher's exact test (two-tailed). RESULTS: The microflora in the urine was not significantly different in patients with preterm labor, PPROM and normal pregnant women. Compared with normal pregnant women, patients with preterm labor had significantly lower prevalences of corynebacteria (p < 0.05) and coagulase-negative staphylococci (p < 0.01) in the cervix, while patients with PPROM had significantly lower prevalences of lactobacilli (p < 0.05) and coagulase-negative staphylococci (p < 0.05) in the cervix. Positive amniotic fluid cultures were detected in three of the 20 patients with preterm labor who underwent transabdominal amniocentesis. Evidence of ascending colonization was found in two of these cases. CONCLUSIONS: The microbial colonization of the urine was not associated with threatening preterm delivery. Reduced prevalences of lactobacilli, corynebacteria and coagulase-negative staphylococci in the cervix were associated with threatening preterm delivery.

Adolescent↗
PubMed1994

Immunity to experimental Salmonella typhimurium infections in rats. Transfer of immunity with primed CD4+CD25high and CD4+CD25low T lymphocytes.

The protective effect of primed CD4+ T lymphocytes against a lethal dose of 10(8) viable Salmonella typhimurium was studied in Lewis rats. Primed CD4+ T lymphocytes were obtained by inoculating Lewis rats with a non-lethal dose of 10(6) viable S. typhimurium. Four weeks after the infection, spleen CD4+ T lymphocytes were separated using magnetic microspheres coated with an antibody against the CD4 molecule (W3/25). Subsequent sorting into activated and non-activated subpopulations using the p55 alpha-chain of the interleukin-2 receptor (CD25) as an activation marker was performed by a fluorescence-activated cell sorter. Untreated Lewis rats were injected with 10(4) different primed CD4+ T-cell populations 24 h prior to the lethal dose of 10(8) viable S. typhimurium. Blood samples were drawn from the orbital plexus 1, 2, 3, and 4 weeks after the infection, and analysed for specific IgM and IgG antibodies. Cell sorting revealed that 2/3 of the primed CD4+ T lymphocytes expressed high levels of CD25. Cell transfer revealed that both CD25high and CD25low expression populations could induce immunity against a lethal dose of S. typhimurium, whilst antibody analysis revealed that antibody levels were not correlated with protection against S. typhimurium infections, although it showed that a higher and more persistent level of specific IgG antibodies was produced in animals receiving the CD4+CD25high fraction. It is concluded that 10(4) primed CD4+ T lymphocytes can induce immunity in animals challenged with a lethal dose of S. typhimurium and that antibodies do not seem to be correlated with the immunity induced. The CD4+CD25high fraction was, however, associated with a higher and more persistent level of specific IgG antibodies.

Animals↗
PubMed1993

Complement activation by Pseudomonas aeruginosa biofilms.

In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact biofilms was submaximal. Factor B conversion was of low magnitude indicating the importance of the classical pathway. Complement activation by P. aeruginosa was inhibited by polymyxin B indicating that lipopolysaccharide (LPS) was the main mediator of complement activation. Immune complexes and massive influx of neutrophils are known to cause inflammatory changes in the lungs. P. aeruginosa persisting in biofilms may contribute to the constant inflammation taking place in the lungs of CF patients.

Chemotaxis, Leukocyte↗
PubMed1993

Induction of oxidative burst response in human neutrophils by immune complexes made in vitro of lipopolysaccharide and hyperimmune serum from chronically infected patients.

Purified lipopolysaccharide (LPS) from Pseudomonas aeruginosa was used as an antigen for immune complex (IC) formation in vitro together with hyperimmune sera from chronically P. aeruginosa-infected patients with cystic fibrosis (CF). P. aeruginosa LPS by itself did not induce an oxidative burst in human neutrophil granulocytes (PMN)s measured by chemiluminescence (CL). This was also the case using hyperimmune CF serum alone. In contrast, P. aeruginosa LPS together with CF serum did induce a CL response. The CL responses varied depending on the sera used for IC formation, and were reduced when protein A preabsorbed sera were used. PEG precipitation of the ICs from the mixture increased the CL response. These findings indicate that the CL responses induced by the mixture of P. aeruginosa LPS and CF serum were due to IC formation and an Fc-mediated stimulation of the PMNs. It is concluded that ICs made from sera of chronically infected CF patients and purified P. aeruginosa LPS are biologically active in terms of activating PMNs, and may contribute to the lung tissue damage seen in this group of patients.

Antibodies, Bacterial↗
PubMed1992

The relationship between prior cervical conization, cervical microbial colonization and preterm premature rupture of the membranes.

The occurrence of prior cervical conization and the cervical microbial colonization was investigated in 38 women with idiopathic preterm labor, 35 women with preterm premature rupture of the membranes (PPROM) and 75 normal pregnant women at 26-34 weeks of gestation. Data were analyzed by Fisher's exact test (two-tailed). The frequency of prior cervical conization was significantly higher in PPROM patients compared to normal pregnant women (P < 0.001) and to patients in preterm labor (P < 0.01). Lactobacilli occurred with a lower frequency in patients with PPROM compared to patients in preterm labor (P < 0.05) and control patients (P = 0.0543)-and with a lower frequency in patients with prior cervical conization (P < 0.05). All other microorganisms occurred with the same frequencies in all groups. The absence of lactobacilli may indicate changes in the cervical flora, which could increase the risk of PPROM. Prior cervical conization may impair the antimicrobial defense-mechanisms in the cervix, which could facilitate ascending microbial colonization. This may lead to a release of prostaglandins and proteolytic enzymes and subsequently preterm labor and rupture of the membranes.

Adult↗
PubMed1992

Some bacterial parameters influencing the neutrophil oxidative burst response to Pseudomonas aeruginosa biofilms.

Persistence of bacteria in spite of a normal host immune system and relevant antibiotic treatment is a key problem in many chronic infections, such as the bronchopulmonary P. aeruginosa infection in cystic fibrosis patients. The capability of bacteria to establish themselves in microcolonies or biofilms is an important protective mechanism of the microorganisms. We examined the human PMN oxidative burst response to P. aeruginosa in biofilm and in planktonic form. The PMN chemiluminescence response to P. aeruginosa in biofilms was reduced to 30.5-47.5% (p less than 0.04) and the superoxide response to 85.9% (p less than 0.02) of the response to equivalent numbers of planktonic bacteria. Mechanical disruption of the biofilms before the assays elicited a significantly increased response in the chemiluminescence experiments and to nonopsonized biofilms in the superoxide anion experiments. We conclude that biofilm bacteria, although able to stimulate the PMN, result in a reduced, suboptimal response leading to lack of efficient eradication of the bacteria in the chronic infection.

Cystic Fibrosis↗
PubMed1991

Group B streptococcal chorioamnionitis and neonatal septicemia following 8 days pivampicillin and metronidazol prophylaxis after premature rupture of membranes; a case report.

A case of preterm premature rupture of the membranes (PPROM) in the 31st week of gestation is reported. Initial cultures from the cervix and urine were without pathogenic microorganisms. After 8 days of prophylactic pivampicillin and metronidazol, culture from the cervix showed profuse growth of Group B Streptococci (GBS) and the patient developed symptoms of chorioamnionitis. Cesarean section was performed and the infant presented GBS-septicemia. In spite of continued treatment with pivampicillin, culture from the cervix on day 6 post partum still showed profuse growth of GBS. Prolonged prophylactic per oral administration of broad-spectrum antibiotics after PPROM may not always protect against infectious complications. Literature is reviewed, and it is discussed whether the applied regimen in some cases even may favour the occurrence of serious infections.

Adult↗
PubMed1991

Induction of beta-lactamase production in Pseudomonas aeruginosa biofilm.

Imipenem induced high levels of beta-lactamase production in Pseudomonas aeruginosa biofilms. Piperacillin also induced beta-lactamase production in these biofilms but to a lesser degree. The combination of beta-lactamase production with other protective properties of the biofilm mode of growth could be a major reason for the persistence of this sessile bacterium in chronic infections.

Culture Media↗