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Biomedical subjects

F Espersen

Publications and source records attributed to F Espersen.

At least 91 records · Page 5Linked to original sources
PubMed1993

Catheter-related Staphylococcus aureus infections.

Among 3394 patients with Staphylococcus aureus bacteraemia from the years 1986-89, 88 patients were found whose intravenous catheter and blood grew organisms of the same phage type. Strains of phage type 95 were more frequent among the patients with confirmed catheter-related bacteraemia than among other bacteraemia cases. Strains with particular phage-type patterns occurring with increasing frequency in Denmark during recent years also occurred with significantly higher frequencies among the confirmed catheter-related bacteraemias. No major differences in antibiotic resistance were observed. Patients with catheter-related bacteraemia had, in spite of a higher frequency of underlying diseases, a lower mortality compared with other bacteraemia patients, and endocarditis occurred less frequently (2% vs. 6%). Among 201 S. aureus isolates from catheters in 1988 only strains of group I occurred with increased frequency. The possible role of catheters as selection pressure on the S. aureus population is discussed.

Adolescent↗
PubMed1993

Experimental foreign body infection in mice.

A number of experimental foreign body infections have been described. We present here an easy, reproducible staphylococcal foreign body infection model in mice. The failure of treatment with methicillin and gentamicin is demonstrated, while the usefulness of antibiotic prophylaxis is documented. The usual correlations between pharmacokinetic parameters and the effect of antibiotics in vivo seem not to hold when a foreign body is present. The model may be applicable to large-scale evaluation of different antibiotic regimens.

Animals↗
PubMed1993

Induction of oxidative burst response in human neutrophils by adherent staphylococci. Comparison between Staphylococcus epidermidis and Staphylococcus aureus.

The ability of staphylococci adherent to silicone surfaces to induce superoxide anion (O2-) production by polymorphonuclear leukocytes (PMNs) was investigated and compared with the same activity induced by planktonic bacteria. The responses to Staphylococcus aureus strain E 2371 and Staphylococcus epidermidis strain ATCC 14990 were compared. The staphylococci were allowed to adhere to silicone catheters for 2 h at 37 degrees C. After opsonization of adherent bacteria in 30% human AB-positive serum, the induction of superoxide anion production by PMNs was measured in a cytochrome C reduction assay. Both bacterial strains, when adhered to the surfaces, were able to induce superoxide anion production by PMNs to about the same extent. Comparing adherent and planktonic bacteria with these two bacterial strains, it was found that planktonic S. epidermidis induced one to three times higher superoxide anion production than the adherent bacteria, whereas planktonic S. aureus induced four to seven times higher superoxide anion production than the adherent bacteria. Interstrain variation between the response to adherent and planktonic staphylococci was found. The lower phagocytic response to adherent staphylococci as compared to the response to planktonic organisms may interfere with the killing process and thereby contribute to poor clearance of these bacteria when adherent to foreign bodies such as catheters.

Humans↗
PubMed1993

Chronic Pseudomonas aeruginosa lung infection in normal and athymic rats.

We have compared a chronic lung infection with Pseudomonas aeruginosa embedded in alginate beads in normal and athymic rats with an acute infection with free live P. aeruginosa bacteria. The following parameters were observed and described: mortality, macroscopic and microscopic pathologic changes, and antibody responses. The rats challenged with P. aeruginosa alginate beads experienced a generally more severe lung pathology and the antibody responses were more homogeneous with less dispersion as compared to the rats having free live P. aeruginosa bacteria. In general, manifestations were more severe in the athymic rats compared to the normal rats. It is, however, notable that the athymic rats developed similar microscopic lung manifestations as the normal rats when given a large number of P. aeruginosa in the beads, with dense accumulation of neutrophil granulocytes and microcolonies comparable to the lesions seen in cystic fibrosis (CF) patients. Early transitory IgM titers were demonstrated in both normal and athymic rats. Whilst athymic rats produced much lower IgG titers than the normal rats, presumably due to the absence of CD4+ cells, higher primary IgA titers were achieved. These two models in normal and athymic rats of the chronic lung infection resembling that seen in CF lungs make it possible to study the influence of the various components of the specific and nonspecific defense systems on the course of the chronic P. aeruginosa lung infection and to evaluate the effect of various immunization schedules and immunomodulatory drugs.

Acute Disease↗
PubMed1992

IgG subclass antibody responses to alginate from Pseudomonas aeruginosa in patients with cystic fibrosis and chronic P. aeruginosa infection.

Chronic bronchopulmonary infection with alginate-producing, mucoid Pseudomonas aeruginosa is characteristically associated with cystic fibrosis (CF). A significant correlation between the antibody response to alginate and poor lung function has been reported. Enzyme-linked immunosorbent assays were developed for the quantitation of human IgG1, IgG2, IgG3, and IgG4 antibodies to P. aeruginosa alginate. We investigated the pattern of IgG subclass antibodies against P. aeruginosa alginate in serum of patients with CF, others with chronic P. aeruginosa infection, and healthy controls. Healthy controls and patients with CF, before they acquired P. aeruginosa infection, had no or very low titers of antibodies against P. aeruginosa alginate. The latter with chronic infection had significantly higher antibody levels than all others groups, including patients with chronic P. aeruginosa infection but no CF. CF with chronic P. aeruginosa infection led to an inverse correlation between lung function parameters and levels of IgG3 and IgG4. Fifty-seven patients with CF have been followed for an average of 12 years with multiple antibody assays covering the preinfection, early, and late stage of chronic infection. All of them developed IgG1 and IgG3 antibodies to alginate at the start of infection. IgG2 antibodies developed later and showed only a slow increase during the chronic infection. Patients who died had significantly higher IgG2 anti-alginate antibody levels than other investigated groups. Elevated levels of IgG2 and IgG3 antibodies to P. aeruginosa alginate are a sign of poor prognosis in CF.

Alginates↗
PubMed1992

Specific opsonic activity for staphylococci in peritoneal dialysis effluent during continuous ambulatory peritoneal dialysis.

In a prospective study of intraperitoneal opsonins in 30 patients undergoing continuous ambulatory peritoneal dialysis (CAPD), the IgG concentration, the fibronectin concentration, the specific antistaphylococcal antibody level, and the opsonic activity against Staphylococcus epidermidis were measured in peritoneal dialysis effluent from the initiation of CAPD and monthly for 6 months. Significant correlation was found between the four assays, but the interindividual and intraindividual variations were considerable. No statistically significant correlation was observed between susceptibility of the patients to CAPD-related infectious peritonitis and any of the above-mentioned parameters of humoral defense. We conclude that at the present time it is not feasible to use these assays for the establishment of prognosis with regard to peritonitis in CAPD.

Adult↗
PubMed1992

The typing of Staphylococcus epidermidis by a lectin-binding assay.

A new typing method for Staphylococcus epidermidis was developed. Four biotinylated lectins--wheat germ agglutinin (WGA), soy bean agglutinin (SBA), lentil agglutinin (LCA) and Concanavalin A (ConA)--were added to immobilised whole cells of coagulase-negative staphylococci (CNS) in microtitration plates. The amount of bound lectin was measured by peroxidase-conjugated avidin followed by a peroxidase reaction. The method was compared to antibiotic-resistance analysis, phage typing, plasmid DNA profiles and slime production. A total of 113 isolates of CNS from 21 patients was investigated and 71 strains of CNS, including 64 strains of S. epidermidis, were detected if all typing methods were taken into consideration. If only one typing method was used the highest discriminatory power among the S. epidermidis isolates was obtained with the lectin-binding assay which allowed 49 different strains to be detected. If the lectin-binding assay was combined with plasmid-profile analysis, all 64 different strains could be identified. The typability of lectin-binding assay was 96.9% among the S. epidermidis isolates and 25 different lectin-binding patterns were established among the 64 strains. The highest number of strains belonging to one lectin-binding pattern was 13 (20.3%). The assay was reproducible, easy to perform, relatively inexpensive and therefore applicable to large scale typing of S. epidermidis.

Bacterial Typing Techniques↗
PubMed1992

Coagulase-negative staphylococci in a newborn with a cardiac vascular prosthesis. Case report.

A case of septicemia with coagulase-negative staphylococci in a newborn with a vascular graft is discussed. Nineteen different isolates of coagulase-negative staphylococci were isolated from four different blood cultures. Eleven of the isolates belonged to one strain, which showed slight variation; the remaining seven isolates belonged to six different strains. The patient was treated for a prolonged period with antibiotics and seemed to respond. The diagnosis and proper treatment are discussed.

Blood Vessel Prosthesis↗
PubMed1992

Immunoglobulin G antibodies to Helicobacter pylori in patients with dyspeptic symptoms investigated by the western immunoblot technique.

Helicobacter pylori is a gram-negative, curved, rod-shaped bacterium known to cause gastritis and to be an important factor in the pathogenesis of peptic ulcers. Serological testing has recently been proposed as an aid in diagnosis of H. pylori infections. In this study, we used the Western immunoblot technique to evaluate the possibility of using one or more of the antigens from H. pylori for this purpose. Thirteen major bands and about 30 minor bands could be identified by Western blotting when sera from 53 consecutive dyspeptic patients, 27 healthy children, and 25 blood donors were evaluated. Antibodies against most of the major bands were found significantly more frequently in patients with H. pylori infections than in patients without such infections. However, antibodies against a single polypeptide were not produced by all patients with H. pylori infection. Polypeptides with molecular masses of 120, 50, and between 19 and 36 kDa seem to be the most specific polypeptides for the diagnosis of H. pylori infections. This study showed only minor differences in antigenic composition between different clinical isolates of H. pylori, and serological cross-reactions with other bacteria were limited. Major serological cross-reactions were found only with Campylobacter jejuni and with bacterial lipopolysaccharide. However, one band at 60 kDa reacted with antiserum to the Legionella micdadei common antigen, which may indicate a cross-reaction with common antigen from several other bacteria. This study demonstrates that a number of bands may be useful as antigens in serological tests after isolation and purification.

Adolescent↗
PubMed1992

Role of alginate in infection with mucoid Pseudomonas aeruginosa in cystic fibrosis.

BACKGROUND: Chronic bronchopulmonary infection with mucoid, alginate producing Pseudomonas aeruginosa occurs characteristically in patients with cystic fibrosis. Alginate may be a virulence factor for P aeruginosa infection in such patients. METHODS: Forced vital capacity (FVC), nutritional state and the antibody response to P aeruginosa were determined at regular intervals from three years before chronic P aeruginosa infection to 10 years afterwards in 73 patients with cystic fibrosis. All patients were treated intensively with antipseudomonal chemotherapy during the study period. RESULTS: FVC was reduced in all patients who subsequently developed P aeruginosa infection before they acquired the infection, indicating significant pre-existing lung damage when compared with patients who remained free of P aeruginosa. Lung function and nutritional state remained unchanged after 10 years of infection, except in the patients who died of P aeruginosa lung infection. The FVC and height and weight of patients infected with nonmucoid strains of P aeruginosa were similar to those of uninfected patients. Patients infected with mucoid strains had poorer lung function and nutritional state for the first five years after infection compared with patients with nonmucoid strains. Such infection was also associated with greater IgG and IgA antibody responses to P aeruginosa standard antigen compared with nonmucoid infection. Concentrations of antibody to alginate were similar in patients with non-mucoid and mucoid infection. Noticeably increased concentrations of IgA antibodies to P aeruginosa standard antigen were observed early after the onset of infection in patients who subsequently died. CONCLUSION: Alginate producing P aeruginosa infection is associated with a hyperimmune response and poor clinical condition, suggesting that alginate production is a virulence factor in such infections in patients with cystic fibrosis.

Adolescent↗
PubMed1992

Immunoglobulin allotypes and IgG subclass antibody response to Pseudomonas aeruginosa antigens in chronically infected cystic fibrosis patients.

Chronic Pseudomonas aeruginosa lung infection is the leading cause of death in patients with cystic fibrosis (CF). Poor prognosis correlates with a high number of anti-pseudomonas precipitins and with high levels of IgG2 and IgG3 anti-pseudomonas antibodies. Reports of several highly significant associations between certain Gm (genetic markers of IgG on human chromosome 14) and Km (k-type light chain determinants on chromosome 2) phenotypes and immune responsiveness to various antigens suggest that allotype-linked immune response genes do exist in man. Furthermore correlation between Gm types and IgG subclass levels has been reported. A group of 143 CF patients were investigated (31 non-infected and 112 chronic infected). The IgG subclass antibodies to three different P. aeruginosa antigens (P. aeruginosa standard antigen (St-Ag), alginate and LPS) were determined. Immunoglobulin allotypes were determined by haemagglutination inhibition. Samples were typed for G1m(1,2,3, and 17), G2m(23), G3m(5,21), and Km(1,3). Statistical analysis of our data demonstrate that IgG3 anti-pseudomonas antibody levels and Gm markers are related. IgG3 antibody levels to all investigated P. aeruginosa antigens are significantly higher in sera homozygous for Gm(3;5), somewhat lower in heterozygous sera, and significantly lower in sera homozygous for Gm(1,2,17;21). We suggest that genetic differences between the patients may explain the present differences in subclass patterns.

Antibodies, Bacterial↗
PubMed1992

Mucosal immunity to Pseudomonas aeruginosa alginate in cystic fibrosis.

Patients with cystic fibrosis commonly acquire chronic pulmonary infection with alginate-producing Pseudomonas aeruginosa. The infection remains localized at the mucosal surfaces of the airways. Using enzyme-linked immunosorbent assays immunoglobulin concentrations and titers of specific antibodies to purified P. aeruginosa alginate and to P. aeruginosa sonicated antigens were measured in tears, saliva, sputum and serum. CF patients had significantly higher concentrations of IgG, IgA and SIgA in serum and saliva than controls. They also had significantly higher levels of specific antibodies to alginate and sonicated antigen in secretions and serum. Local production of IgA, IgG and IgM antibodies to P. aeruginosa was demonstrated. Only a minor proportion of specific IgA antibodies were present as secretory IgA in tears, saliva and sputum. The ratio of alginate-specific SIgA to specific monomeric IgA in sputum was significantly lower than the similar ratio in saliva, whereas the same ratio for specific P. aeruginosa sonicate antigens was found in saliva and sputum.

Adolescent↗
PubMed1991

[Respiratory tract infection and acute deterioration of obstructive lung disease].

Respiratory infection may aggravate chronic obstructive pulmonary disease. Viral respiratory infections may aggravate asthma, particularly in young individuals. Respiratory Syncytial virus and Rhinovirus dominate in children while, in adults, Influenza or Rhinovirus infections are most frequently concerned. Viral respiratory infections may also cause exacerbation of chronic bronchitis. Bacteria and their products scarcely play any part in asthmatic disease but may possibly aggravate chronic bronchitis and other forms of obstructive respiratory disease. In particular, Haemophilus influenzae and Streptococcus pneumoniae and bacterial endotoxin appear to be of significance. The mechanisms of the effects of viruses have several points of attack: Destruction of epithelium, release of mediators, potentiation of mediator-release and reduced beta-adrenergic function. Bacteria and their products may, similarly, cause bronchoconstriction and may, in vitro, release mediators and potentiate release of mediators.

Bacterial Infections↗
PubMed1991

Role of the Yersinia outer membrane protein YadA in adhesion to rabbit intestinal tissue and rabbit intestinal brush border membrane vesicles.

The Yersinia virulence plasmid confers on strains of Yersinia pseudotuberculosis and Y. enterocolitica an adhesive potential superior to the one encoded by the chromosome alone. We have evaluated the role of the plasmid-encoded outer membrane protein YadA (formerly called Yopl) in adhesion. Insertional inactivation of the yadA gene (formerly called yopA), which encodes YadA, led to a reduction in the capacity of plasmid-carrying strains of Y. pseudotuberculosis 0:III and Y. enterocolitica 0:9 to adhere to intestinal tissue, brush border membranes and polystyrene surfaces. The adhesive characteristics of the mutants were comparable to those of their plasmid-cured counterparts. When the yadA gene from Y. pseudotuberculosis serotype 0:III or Y. enterocolitica serotype 0:3 or 0:8 was cloned into an Escherichia coli strain, increased ability to adhere to intestinal tissue, brush border membrane vesicles and polystyrene was transferred concomitantly. The introduction of the yadA gene from Y. pestis, which is unable to express YadA due to a one base pair deletion, did not change the adhesive characteristics of E. coli. Expression of YadA in the outer membrane may, therefore, make an important contribution to intestinal adherence of the two enteropathogenic members of the Yersinia species, Y. pseudotuberculosis and Y. enterocolitica.

Animals↗
PubMed1991

Interactions between Yersinia enterocolitica and rabbit ileal mucus: growth, adhesion, penetration, and subsequent changes in surface hydrophobicity and ability to adhere to ileal brush border membrane vesicles.

Interactions between Yersinia enterocolitica and rabbit ileal mucus were examined. Strains carrying the Yersinia virulence plasmid, pYV, adhered to crude mucus but not to intestinal luminal contents that had been immobilized on polystyrene. Using an Y. enterocolitica O:9 mutant in which the yadA gene (formerly called yopA), encoding the high-molecular-weight outer membrane protein YadA (formerly called protein P1 or Yop1), had been inactivated and an Escherichia coli strain carrying the cloned yadA gene, we demonstrated that the ability to adhere to mucus correlated closely to expression of YadA. Thereafter, we evaluated possible consequences of binding between pYV-carrying Y. enterocolitica O:3 strains and constituents in the mucus layer. pYV-carrying strains were able to multiply at a high rate in mucus but not in luminal contents, and the ability to adhere to mucus could therefore facilitate bacterial colonization of the mucosa. However, we also showed in vitro that mucus acted as a barrier for a mucus-adherent, pYV-carrying Y. enterocolitica strain. Furthermore, penetration through, or preincubation with, mucus reduced subsequent adhesion of the pYV-carrying strain to brush border membrane vesicles without simultaneously causing bacterial aggregation. Preincubation with mucus also changed the bacterial surface of the same strain from hydrophobic to hydrophilic. Immunoglobulins present in mucus did not seem to be of importance for our observations. Interaction of Y. enterocolitica with intestinal mucus may thus reflect a host defense mechanism that reduces the pYV-mediated adhesion to the epithelial cell membrane, possibly by rendering the bacteria less hydrophobic.

Animals↗