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N Høiby

Publications and source records attributed to N Høiby.

At least 19 recordsLinked to original sources
PubMed1995

[Cholera in Denmark--an imported case of illness].

A case of cholera imported to Denmark from the Pacific is presented. The patient was successfully treated with rehydration and antibiotics. A survey of the ongoing seventh pandemic of cholera is given and the possible emergence of a new eighth pandemic is discussed. Guidelines for prophylactic and therapeutic measures are discussed. Although V. cholerae colonies can be recognized on routine cultivation media, low numbers require selective media, and this is not included in routine investigations of stools for pathogens.

Cholera↗
PubMed1995

Prevalence and antibiotic sensitivity of Danish versus other European bacterial isolates from intensive care and hematology/oncology units.

The prevalence and antibiotic sensitivity patterns of bacteria collected consecutively from medical and surgical intensive care units (ICUs) and from hematology/oncology units in nine hospitals in Denmark were determined and compared to data collected simultaneously in 12 other European countries. Bacterial isolates from 794 Danish patients were tested and compared to 8,625 isolates from European patients. The minimal inhibitory concentrations of eight different antibiotics were determined using a microdilution plate. Similar to findings in European countries, the most common source of bacterial isolates in Danish units was the respiratory tract (49%), followed by blood (18%), urinary tract (14%) and surgical wounds (10%). Staphylococcus aureus was the most prevalent respiratory organism in Danish units, whereas Enterobacteriaceae and Pseudomonas aeruginosa dominated in other countries. In blood, Escherichia coli was most prevalent in Denmark while coagulase-negative staphylococci were predominant in other countries. Urinary tract isolates were dominated by Escherichia coli in both Denmark and the other countries, but Enterococcus faecalis and Pseudomonas aeruginosa were more frequently isolated in the other countries. Staphylococcus aureus was the most frequent wound isolate in Denmark, while Enterobacteriaceae other than Escherichia coli dominated in other European countries. Thus, in Denmark Escherichia coli and Staphylococcus aureus, followed by Pseudomonas aeruginosa and Klebsiella spp. (from ICUs) or Enterococcus spp. and Klebsiella spp. (from hematology/oncology units), are the most prominent pathogens in these units today. Indicator organisms of antibiotic consumption (Pseudomonas aeruginosa and methicillin-resistant coagulase-negative staphylococci and Staphylococcus aureus) were more frequent in other European countries than Denmark. In general the Danish isolates were more sensitive to antibiotics than the European isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1995

Epidemiology of Pseudomonas aeruginosa infection and the role of contamination of the environment in the Danish Cystic Fibrosis Centre.

In order to identify the possible reservoirs and routes of cross-infection with Pseudomonas aeruginosa, samples were collected during a six-week period in autumn 1992 from patients, their visiting parents, staff and the inanimate environment of the Danish Cystic Fibrosis (CF) Centre and from a control ward with common paediatric diseases. All the P. aeruginosa strains were phage typed and serotyped. From 240 CF patients, 310 strains of P. aeruginosa were isolated, and of these 283 (91.3%) belonged to the polyagglutinable phenotype, most often with a short phage type (31/188 or 109). P. aeruginosa was isolated from only six (0.6%) of 1000 swabs taken from the environment. These six environmental strains and 20 P. aeruginosa strains from CF patients with identical serotype and phage type were examined with pulsed field gel electrophoresis. None of the patients harboured strains similar to the environmental strains, indicating the present isolation procedure and hygienic precautions were effective in our CF centre, and prevented contamination of the environment with P. aeruginosa.

Bacterial Typing Techniques↗
PubMed1995

Isolation and treatment of cystic fibrosis patients with lung infections caused by Pseudomonas (Burkholderia) cepacia and multiresistant Pseudomonas aeruginosa.

Cross-infection with Pseudomonas aeruginosa and Pseudomonas cepacia has been shown sometimes to occur between cystic fibrosis (CF) patients in some CF centres, in some summer camps and during some social contacts between CF patients. Cohort isolation and improved hygienic precautions, however, have successfully been employed in some CF centres resulting in a decrease or elimination of cross-infection. Chronic P. aeruginosa infection is in most CF patients preceded by a period of intermittent colonization. Early aggressive chemotherapy (oral ciprofloxacin and nebulized colistin for 3 weeks) every time P. aeruginosa is detected in sputum has significantly decreased the incidence of new chronic infection in CF patients. Chronic P. aeruginosa infection can be treated by "maintenance chemotherapy" (= chronic suppressive chemotherapy). The principle is to restore lung function repeatedly by regular 2-week courses of intensive intravenous treatment every 3 months in the CF centre and adding daily inhalations of colistin between the courses, and sometimes also by giving oral ciprofloxacin during these intervals to unstable patients. Eradication of P. cepacia infection is virtually never obtained by antibiotic treatment with, e.g., ceftazidime and tobramycin or co-trimoxazole. Chronic suppression with doxycyclin or co-trimoxazole may give rise to some improvement in the clinical symptoms.

Adolescent↗
PubMed1995

Antibodies against Pseudomonas aeruginosa chromosomal beta-lactamase inpatients with cystic fibrosis are markers of the development of resistance of P. aeruginosa to beta-lactams.

Chromosomal beta-lactamase production is considered to be the most important resistance mechanism of Pseudomonas aeruginosa against beta-lactams. Recently we have detected serum and sputum antibodies against P. aeruginosa chromosomal beta-lactamase (a beta ab), using immunoblotting techniques. In this study we have developed an enzyme-linked-immunosorbent assay to measure serum a beta ab response in 124 cystic fibrosis patients in a cross-sectional study and in 54 cystic fibrosis patients in a longitudinal study. The a beta ab response occurred after a median of 3 years following onset of chronic infection and was significantly higher (P < 0.0002) in patients chronically infected with resistant strains than in those from whom resistant strains were occasionally isolated. The a beta ab levels correlated (r = 0.51, P = 0.0001) with the number of beta-lactam courses. A 14 fold increase in a beta ab levels occurred during the 14 year period covered by the longitudinal study. The results of this study show that a beta ab to P. aeruginosa is a specific marker for resistance development of P. aeruginosa to beta-lactams.

Adolescent↗
PubMed1995

An easy microtiter assay for quantitation of cytokine induction by lipopolysaccharide (LPS) and activity of LPS-binding serum components.

Lipopolysaccharide (LPS, endotoxin) is a major inducer of cytokines, such as interleukin 1 (IL1), IL6, IL8 and tumor necrosis factor (TNF). A convenient microtiter assay was developed to measure such activity. LPS coated onto a plastic surface was used to stimulate purified human mononuclear cells (MNC) in microtiter plates. Following stimulation the supernatants were assayed for presence of TNF by ELISA. Purified rough and smooth LPS from Pseudomonas aeruginosa gave a dose-dependent TNF release over a range of 0.1-1.0 microgram LPS/well. The assay was subsequently used to investigate the biological activity of anti-LPS antibodies and other LPS-specific serum components in sera from patients with cystic fibrosis (CF). As a group, sera from 10 CF patients chronically infected with P. aeruginosa did not affect the LPS-induced TNF release, while sera from normal controls inhibited this biological activity. When individual CF patients with or without chronic lung infection are considered, the antibodies appear to either enhance or inhibit the LPS-stimulated TNF release (range: 73-120%), while all antibodies from healthy controls inhibit the activity of LPS (range: 76-97%). Only a weak correlation (rho = 0.491, p = 0.037, n = 19) was found between the antibody titer in ELISA and the biological activity of sera. This new assay is suggested for convenient measurement of interference with cytokine induction from human MNC by patient or therapeutic anti-LPS antibodies and other LPS-specific serum components.

Antibodies, Bacterial↗
PubMed1995

Cross-reactive antigens shared by Pseudomonas aeruginosa, Helicobacter pylori, Campylobacter jejuni, and Haemophilus influenzae may cause false-positive titers of antibody to H. pylori.

Cystic fibrosis (CF) patients suffer from many of the gastrointestinal conditions which occur in non-CF individuals, e.g., dyspepsia and peptic ulceration. These symptoms may be caused by Helicobacter pylori but could also be due to either pancreatic insufficiency or the intensive antibiotic treatment used in CF patients. Since CF patients chronically infected with Pseudomonas aeruginosa produce antibodies against a wide range of antigens, including antigens common to many other bacteria, e.g., GroEL and lipopolysaccharide, we studied, by the Western blot (immunoblot) technique, the specificity of immunoglobulin G antibodies to H. pylori in Danish CF patients chronically infected with P. aeruginosa, CF patients without P. aeruginosa infection but with Haemophilus influenzae infection, patients with dyspeptic ulcers associated with H. pylori, and patients recovering from acute Campylobacter jejuni or Campylobacter coli infection. Sera from CF patients with chronic P. aeruginosa or H. influenzae infection and patients recovering from acute C. jejuni infection cross-reacted with H. pylori antigens. A strong cross-reacting protein antigen at approximately 14 kDa and minor cross-reactive antigens at approximately 27, 30, and 60 kDa (the heat shock protein GroEL is equivalent to the common antigen of P. aeruginosa) could be demonstrated. The results of this study show that high immunoglobulin G antibody titers against H. pylori in CF patients cannot be regarded as indicating present or past H. pylori infection unless their specificity is proven by absorption studies.

Antibodies, Bacterial↗
PubMed1995

Restriction fragment length polymorphism of rRNA genes for molecular typing of members of the family Legionellaceae.

Typing of Legionella pneumophila remains important in the investigation of outbreaks of Legionnaires' disease and in the control of organisms contaminating hospital water. We found that the discriminatory power of a nonradioactive ribotyping method could be improved by combining results obtained with four restriction enzymes (HindIII, NciI, ClaI, and PstI). Fifty-eight clinical and environmental L. pneumophila strains including geographically unrelated as well as epidemiologically connected isolates were investigated. Epidemiologically related strains had the same ribotypes independent of the combinations of enzymes used. Some strains belonging to the same serogroup were assigned to different ribotypes, and some ribotypes contained members of different serogroups, indicating, as others have found, that serogroup and genotype are not always related. The discriminatory power of the method was estimated by calculating an index of discrimination (ID) for individual enzymes and combinations thereof. The combined result with all four enzymes was highly discriminatory (ID = 0.97), but results for three enzymes also yielded ID values acceptable for epidemiological purposes. In addition, the testing of 27 type strains and 6 clinical isolates representing Legionella species other than L. pneumophila indicated that ribotyping might be of value for species identification within this genus, as previously suggested.

Bacterial Typing Techniques↗
PubMed1995

Diminished concentrations of insulin-like growth factor I in cystic fibrosis.

Cystic fibrosis is frequently accompanied by a catabolic condition with low body mass index caused by a number of disease complications. Insulin-like growth factor-I (IGF-I) is an anabolic hormone and an important marker of nutritional status, liver function, and linear growth. Available data on IGF-I in cystic fibrosis are sparse and conflicting. From 1990-3, 235 of our 240 patients (114 males, 121 females, median age 16.2 years, ranged 0.1-44.0 years) had IGF-I measured once by radioimmunoassay. IGF-I was significantly reduced compared with a healthy Scandinavian control population: mean (-2 SD to +2 SD) IGF-I SD score was -0.97 (-3.7 to 1.7) in males and -0.67 (-3.2 to 1.9) in females. Height SD score was -0.95 (-3.3 to 1.4) in males and -0.81 (-3.2 to 1.6) in females. In patients who were still in the growth period a significant correlation of IGF-I SD score to height SD score (r = 0.28, p < 0.001) was found. The low IGF-I concentrations may reflect the catabolic state of many patients with cystic fibrosis and play a part in their abnormal growth pattern.

Adolescent↗
PubMed1995

Vaccination promotes TH1-like inflammation and survival in chronic Pseudomonas aeruginosa pneumonia in rats.

In a rat model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis (CF) we studied whether the inflammatory response could be altered by vaccination. Rats were immunized with either a depolymerized alginate toxin A conjugate (D-ALG toxin A), purified alginate, an O-polysaccharide toxin A conjugate, or sterile saline. After challenge none of the rats immunized with D-ALG toxin A died, in contrast to the other two vaccine groups combined (p = 0.03). A significant reduction in the severity of the macroscopic lung inflammation was seen in rats immunized with D-ALG toxin A, compared with the other three groups (p = 0.009). The histopathologic response in the control rats was dominated by numerous polymorphonuclear leukocytes (PMN) surrounding the alginate beads. In contrast, the histopathologic response in rats immunized with D-ALG toxin A changed within the first week after challenge from predominantly PMNs (TH2-like) to a chronic-type inflammation dominated by mononuclear leukocytes (TH1-like). In accordance, the antibody titers induced by the D-ALG toxin A vaccine were not different from those of the control rats after challenge. This study identifies a possible new way of modifying the inflammation and thereby preventing the PMN-mediated lung tissue damage during chronic P. aeruginosa lung infection in CF.

Alginates↗
PubMed1995

Cloning and nucleotide sequence comparison of the groE operon of Pseudomonas aeruginosa and Burkholderia cepacia.

By alignment of GroEL amino acid sequences from four distantly related bacteria two highly conserved domains were identified. Two oligonucleotides complementary to the conserved domains were designed based on the preferred Pseudomonas aeruginosa codon usage. The primers were used in the PCR to amplify a 900-base fragment of the P. aeruginosa groEL gene. The fragment was sequenced and the partial GroEL sequence was expanded by vectorette PCR upstream and downstream to cover the complete P. aeruginosa groE operon. The same technique was used to sequence the Burkholderia cepacia (formerly Pseudomonas cepacia) groE operon and the region immediately upstream of groES. The B. cepacia groE operon is preceded by typical -10 and -35 heat shock expression signals. A total of 2041 and 2139 bp was sequenced from P. aeruginosa and B. cepacia respectively. Each revealed two open reading frames encoding two proteins with a predicted molecular mass of 10 and 57 kDa, corresponding to GroES and GroEL respectively. The GroEL proteins show an interspecies amino acid homology of 71%, and 73% with E. coli GroEL. Both GroEL proteins are 52% homologous to the corresponding human mitochondrial GroEL protein. The sequence data confirm the existence of highly conserved structures, which could be functionally important for the concerted action of GroEL and GroES in the folding and assembly of other proteins, and possibly in the initiation of autoimmune diseases.

Adolescent↗
PubMed1995

Experimental chronic Pseudomonas aeruginosa lung infection in rats. Non-specific stimulation with LPS reduces lethality as efficiently as specific immunization.

In a rat model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis, we investigated the possibility of preventing chronic lung inflammation or decreasing the progression of the infection. We compared the lethality, pathology, bacterial clearance, and immunogenicity after stimulation of the non-specific defence mechanisms by Escherichia coli lipopolysaccharide (LPS) or P. aeruginosa sonicate, or the acquired specific immune response by vaccination with the same bacterial antigens. One day prior to challenge with P. aeruginosa embedded in alginate beads, rats were stimulated with either E. coli LPS or P. aeruginosa sonicate. Four and two weeks prior to challenge other rats were vaccinated with either E. coli LPS or P. aeruginosa sonicate. Controls did not receive any stimulation or vaccination. The lethality after challenge was lower in rats stimulated with E. coli LPS (p = 0.02) or vaccinated with P. aeruginosa sonicate (p = 0.03) as compared to controls. The histopathology of the surviving rats showed an acute inflammation dominated by polymorphonuclear leukocytes (PMNs), but the offending bacteria were not completely eliminated in any group. The increased survival was probably due to earlier recruitment of PMNs most likely mediated by either cytokines and other chemotactic factors (stimulated group) or the immune response in concert with the complement cascade (vaccinated group). The results of the present and previous vaccination studies show that it is possible to improve survival but not to prevent the chronic P. aeruginosa lung infection and inflammation caused by alginate-embedded bacteria.

Animals↗
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↗