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Biomedical subjects

B Bruun

Publications and source records attributed to B Bruun.

At least 37 records · Page 2Linked to original sources

Diversity of nosocomial Xanthomonas maltophilia (Stenotrophomonas maltophilia) as determined by ribotyping.

Seventy-seven clinical isolates of Xanthomonas maltophilia (Stenotrophomonas maltophilia) were consecutively collected from the Rigshospitalet, Copenhagen, ribotyped and compared with the ribotypes of 25 other clinical and reference strains of Xanthomonas maltophilia. Using restriction enzyme EcoRI, 20 different ribotypes were observed, with 78 isolates displaying the five most common types. Using another enzyme, BamHI, these 78 isolates were further subdivided into 16 different ribotypes. Three patients harboured two strains with different ribotypes. No type was found related to only one department and no single-strain outbreak was detected. The origin of this wealth of different strains in hospital patients needs to be established.

Bacterial Typing Techniques↗

Serum antibody response to proteins of Moraxella (Branhamella) catarrhalis in patients with lower respiratory tract infection.

We searched for antibodies against Moraxella (Branhamella) catarrhalis proteins in the sera of patients with lower respiratory tract infection. Sera from 48 patients with M. catarrhalis and 39 patients without M. catarrhalis in their lower respiratory tract specimens were studied by a gel electrophoresis-immunoperoxidase technique; sera from 23 healthy adult blood donors were also included. Immunoglobulin G (IgG) antibodies against a 28-kDa protein were found significantly more frequently in patients with M. catarrhalis in lower respiratory tract specimens (71%) than in patients without M. catarrhalis in lower respiratory tract specimens (28%) or healthy adult blood donors (22%). Seroconversion, from the acute to the convalescent stages, occurred in at least eight patients with M. catarrhalis and in one patient without detectable M. catarrhalis. IgG antibodies against other M. catarrhalis proteins were found in most sera, including those obtained from blood donors. By adsorption experiments the 28-kDa protein was demonstrated to be surface exposed. IgM antibodies against an 85-kDa protein were found in serum from one patient from whom M. catarrhalis and Streptococcus pneumoniae were isolated from the lower respiratory tract, while IgA antibodies against M. catarrhalis proteins could not be detected in any serum specimen.

Acute Disease↗

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↗

Candida albicans meningitis in a 27 weeks premature infant treated with liposomal amphotericin-B (AmBisome)

We report a case of Candida albicans meningitis in a neonate born after 27 weeks of gestation. To the best of our knowledge this is the first report of a premature infant with Candida-meningitis treated with liposomal amphotericin B (AmBisome(R)). The patient did not respond well to conventional Amphotericin B, but was successfully cured with Ambisome(R). Liposomal amphotericin B was well tolerated and the baby recovered with a postinfectious hydrocephalus which necessitated a permanent ventriculo-peritoneal shunt. Six months after the infection the baby appears to have a near-normal cerebral development.

Amphotericin B↗

Genotypic and phenotypic relatedness of 80 strains of Branhamella catarrhalis of worldwide origin.

80 clinical Branhamella catarrhalis strains of worldwide origin were examined for genotypic relatedness and phenotypic characteristics. Using a quantitative bacterial dot method for DNA-DNA hybridization the strains were found to form a homogeneous group with delta Tm-values ranging from 0.0-2.3 degrees C, In Minibact-N, an identification kit for oxidase positive, Gram-negative diplococci using eight phenotypic characteristics, all isolates were correctly identified and also demonstrated complete homogeneity except for beta-lactamase production. Type strains representing the genera Branhamella, Moraxella and Neisseria were also examined for comparison. B. catarrhalis strain NCTC 4103-known to be atypical-had a delta Tm-value of 5.7 degrees C and produced gamma-glutamylaminopeptidase, in contrast to all other B. catarrhalis strains. In GN MicroPlate, a kit which tests utilizable carbon sources, B. catarrhalis strains were found to be able to utilize up to 16 to 95 carbon sources.

Carbon↗

Ciprofloxacin as prophylaxis for urinary tract infection: prospective, randomized, cross-over, placebo controlled study in patients with spinal cord lesion.

To evaluate the efficacy of low-dose long-term treatment with ciprofloxacin in the prevention of recurrent urinary tract infections in patients with spinal cord lesions and neurogenic bladder dysfunction, a prospective, randomized, cross-over, placebo-controlled study was performed. The study period was 12 months long, including 6 months of treatment with 100 mg. ciprofloxacin at night and 6 months of placebo treatment. The study was completed by 18 men and 3 women, median age 38 years (range 19 to 73 years). Within the last 12 months before inclusion into the study, the patients had between 3 and 14 urinary tract infections (mean 5.8) treated with antimicrobial agents. The number of urinary tract infections treated with antimicrobial agents during 6 months of ciprofloxacin prophylaxis was 5 and during the 6 months of placebo treatment it was 59 (p < 0.00005) [corrected]. Fecal specimens showed supercolonization with ciprofloxacin resistant bacteria (Acinetobacter calcoaceticus) in 1 instance. No severe side effects were observed. Ciprofloxacin at a dose of 100 mg. at night was efficacious in preventing urinary tract infections during 6 months in patients with spinal cord lesions and neurogenic bladder dysfunction. After the controlled study 10 of the 21 patients used ciprofloxacin as prophylaxis for up to 39 months with a marked reduction in the pre-study infection frequency. In 1 patient ciprofloxacin resistant Escherichia coli was subsequently found in the feces.

Adult↗

Ribotyping for differentiating Flavobacterium meningosepticum isolates from clinical and environmental sources.

On the basis of DNA-DNA hybridization data, two main genomic relatedness groups (I and II) have been reported for a geographically varied collection of 52 strains of Flavobacterium meningosepticum. Herein, we have shown that genomic group II can be further divided into four subgroups (II:1 to II:4). To examine the taxonomic relevance of the ribosomal patterns of the 52 F. meningosepticum strains, the patterns were compared with existing DNA-DNA hybridization data with restriction enzymes PstI and HindIII. Ribotyping of the 52 F. meningosepticum strains showed banding patterns that could identify them correctly to one of the five genomic groups or subgroups. To assess the value of ribotyping for the interpretation of epidemiological data, the discriminatory power of the method was investigated for the 52 F. meningosepticum strains. With one to four restriction enzymes (PstI, HindIII, ClaI, EcoRI), a discriminatory index of 0.95 to 0.97 was found. The value of ribotyping in an epidemiological setting was assessed for three clinical isolates of F. meningosepticum from an outbreak of meningitis and bacteremia in the neonatal intensive care unit, Rigshospitalet, Copenhagen, Denmark. The three clinical isolates were shown to belong to the same ribotype, characteristic of genomic subgroup II:1. This ribotyping method will prove to be a useful tool for epidemiological studies concerning F. meningosepticum in the future.

Bacteremia↗

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↗

Changing etiology of bacteremia in patients with hematological malignancies in Denmark.

To ascertain whether the microbiological etiology of bacteremia among patients with hematological malignancies has changed in Denmark, the species distribution of clinically relevant blood culture isolates from the Hematological Department at Rigshospitalet, Copenhagen in 1990 was compared with 2 previous studies (1970-72; 1981-85). In addition, time trends of the etiology of bacteremia among hematological patients in Copenhagen (eastern Denmark) and in Arhus (western Denmark) were compared. In contrast to many other studies, a significant increase in the proportion of Gram-negative aerobes was observed in Copenhagen (from 43% in 1981-85 to 55% in 1990; p < 0.05), whereas in Arhus the proportion of Gram-positive aerobes increased steadily during the 1980s (from 34% to 51%; p < 0.05). In Copenhagen, non-hemolytic streptococci and Xanthomonas maltophilia increased significantly and accounted for 10% (p < 0.01) and 5% (p < 0.05) respectively, of all isolates in 1990, whereas Staphylococcus aureus during the 2 decades studied decreased from 25% to 8% (p < 0.001). In both regions, a decrease was observed in the proportion of Pseudomonas aeruginosa which accounted for only about 5% of all isolates in 1990. No changes were observed in the rates of anaerobes and yeasts. Several factors may contribute to the reported differences in the etiology of bacteremia among hematological patients, e.g. criteria used to assign the clinical significance of the isolate, blood culture system used, practice of using indwelling intravenous catheters, different policies with respect to antimicrobial treatment, and the degree of immunosuppression. A local surveillance of blood culture isolates is mandatory if changes in etiology and resistance development are to be detected.

Bacteremia↗

Xanthomonas maltophilia bacteremia in immunocompromised hematological patients.

Epidemiological, microbiological and clinical characteristics of 14 episodes of Xanthomonas maltophilia bacteremia in 12 seriously immunocompromised hematological patients, admitted to Rigshospitalet in Copenhagen over the 3-year period 1989-91, were evaluated. The results were compared with a randomly selected control group of 25 patients with Escherichia coli bacteremia. Hospital acquired bacteremia was more common among the patients with X. maltophilia bacteremia (p < 0.01). Treatment with broad-spectrum antibiotics before the bacteremic episode was markedly more common among the patients with X. maltophilia bacteremia (p < 0.001). The presence of a central venous catheter and previous treatment with corticosteroids were more frequent in patients with X. maltophilia bacteremia (p < 0.05). The X. maltophilia blood culture isolates were generally resistant to aminoglycosides and most beta-lactams. The mortality rates related to bacteremia caused by X. maltophilia and E. coli were 14% and 20%, respectively.

Adolescent↗

Infections in patients treated with high-dose chemotherapy for germ cell tumours.

25 patients with disseminated germ cell tumours were treated with high-dose cisplatin and etoposide (40 mg/m2 and 200 mg/m2 daily x five, respectively) leading to severe myelosuppression. A comprehensive study was undertaken in order to identify and describe the bacterial, viral and fungal infections in this group of patients. Fever (> 38.5 degrees C) and leucopenia (white blood cell count < 1.0 x 10(9)/l) were observed in 61 of 90 treatment cycles (68%). A microbiological aetiology compatible with the clinical manifestations of infection could be identified in 33 of the 61 febrile episodes (54%). Bacteraemia occurred in 14 episodes in 12 patients. Eight episodes (57%) involved gram-positive aerobic bacteria.

Adult↗

Cross-reactive antigen recognition by an encephalitogenic T cell receptor. Implications for T cell biology and autoimmunity.

The dominant immune response to rat myelin basic protein in H-2u mice is directed against the acetylated, N-terminal peptide Ac1-11 (AcASQKR-PSQRHG). This peptide causes encephalomyelitis on injection into mice of the H-2u haplotype. Only two residues of the peptide are required for ligation of the TCR from an Ac1-11-specific T cell hybridoma. Proline at position 6 could not be substituted by any other L-amino acid, whereas glutamine at position 3 could be replaced by phenylalanine, histidine, methionine, or tyrosine. Cross-reactive recognition of these residues appears to be specific, because increasing the affinity of each analogue for its MHC restriction element, by replacing lysine with tyrosine at position 4, did not alter the pattern of cross-reactivity. For the majority of substitutions at this position, a lack of stimulation could not be explained by failure to bind to I-Au. However, competition binding studies showed that introduction of proline at position 3 reduced the efficacy of binding to I-Au. Cross-reactive analogues of Ac1-11 were injected into H-2u mice to test the extent to which cross-reactive T cell activation might lead to autoimmune disease in this model. An analogue containing methionine at position 3 caused clinical experimental autoimmune encephalomyelitis in a small percentage of H-2u mice.

Amino Acid Sequence↗

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↗

High prevalence of Clostridium difficile diarrhoea during intensive chemotherapy for disseminated germ cell cancer.

A prospective, consecutive study of the aetiology of treatment-associated diarrhoea was conducted in 25 patients with disseminated germ cell cancer treated with intensive chemotherapy. Clostridium difficile was isolated in 45% of the diarrhoea episodes, which makes this species the most important bacterial pathogen in the development of clinically significant diarrhoea in this group of immunocompromised patients.

Antineoplastic Combined Chemotherapy Protocols↗

Peritonitis with Mycobacterium fortuitum in a patient on continuous ambulatory peritoneal dialysis.

A 35-year-old man on continuous ambulatory peritoneal dialysis (CAPD) developed peritonitis due to Mycobacterium fortuitum and coagulase-negative staphylococci, following an unsuccessful renal transplantation. Infection subsided after removal of the dialysis catheter and treatment with amikacin. Clinicians and microbiologists should be aware of M. fortuitum as a potential cause of peritonitis in patients with debilitating underlying diseases. It is able to grow on ordinary culture media, but detection requires prolonged incubation, and it may be confused with poorly characterized diphtheroids.

Adult↗

Non-typhoid Salmonella bacteraemia in Greater Copenhagen 1984 to 1988.

A retrospective survey of non-typhoid Salmonella bacteraemia in the period 1984 to 1988 was carried out by the five departments of clinical microbiology in Greater Copenhagen. A total of 168 patients were identified. A gradual increase was observed from 11 cases in 1984 to 58 cases in 1988. The corresponding incidence per 100,000 inhabitants in Copenhagen rose from 0.9 in 1984 to 5.0 in 1988. During the same period the total registered incidence of human Salmonella infections in Denmark increased from 17.6 to 67.4 per 100,000 inhabitants. The serotype most often isolated from bacteraemic patients was Salmonella dublin followed by Salmonella enteritidis and Salmonella typhimurium. Salmonella dublin demonstrated enhanced invasive and pathogenic properties. Predisposing factors were present in 56% of the patients; the most common was malignant disease. A fatal or complicated course of the bacteraemia was observed more frequently in patients with underlying diseases than in persons who had previously been healthy. A total of 17% of the patients died; one-fifth of these had a ruptured aortic aneurysm. It is concluded that the substantial increase in the number of cases and the often serious course taken by the infection demonstrate a need for increased efforts at prophylaxis.

Adolescent↗