| 1. |
- Ekdahl, Karl, et al.
(author)
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Bronchoscopic diagnosis of pulmonary infections in a heterogeneous, nonselected group of patients
- 1993
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In: Chest. - 1931-3543. ; 103:6, s. 1743-1748
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Journal article (peer-reviewed)abstract
- Fiberoptic bronchoscopy with bronchoalveolar lavage and protected specimen brush technique has become an established method for etiologic diagnosis in severe forms of pulmonary infections during recent years. In this study, including 62 bronchoscopies in 53 patients, a standardized program, covering all important pulmonary pathogens, has been evaluated in a heterogeneous group of patients. Results providing therapeutic guidelines were obtained in 53 percent (16/30) of the immunocompromised patients (including 5 bronchoscopies on HIV-positive patients), but only 19 percent (6/32) of the immunocompetent patients (p < 0.001). We conclude that bronchoscopy is of great value for diagnosing pulmonary infections in immunocompromised patients. In immunocompetent patients, the diagnostic yield is lower and the indication for bronchoscopy must be established for each individual patient based on clinical importance, resources, and risk. When bronchoscopy is performed, we believe that a standardized program like ours reduces the risk of missing important pathogens.
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| 2. |
- Abate, Getahun, et al.
(author)
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Direct colorimetric assay for rapid detection of rifampin-resistant Mycobacterium tuberculosis
- 2004
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In: Journal of Clinical Microbiology. - 1098-660X. ; 42:2, s. 871-871
-
Journal article (peer-reviewed)abstract
- The colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was standardized for direct detection of rifampin-resistant Mycobacterium tuberculosis in sputum samples. The sensitivity and specificity of the direct MTT assay matched those of the standard indirect susceptibility assay on 7H10 medium, and interpretable results were obtained for 98.5% of the samples within 2 weeks. Traditional methods of in vitro drug susceptibility testing are time consuming and laborious. Susceptibility tests on clinical isolates require 6 to 9 weeks, and tests conducted directly on smear-positive samples take about 3 weeks (International Union Against Tuberculosis and Lung Disease, The public health service national tuberculosis reference laboratory and the national laboratory network. Minimum requirements, role and operation in a low-income country, Paris, France, 1998, and P. T. Kent and G. P. Kubica, Public health mycobacteriology. A guide for the level III laboratory, Centers for Disease Control and Prevention, Atlanta, Ga., 1985). More-rapid methods are available but are very expensive for routine use under program conditions in countries with high levels of tuberculosis endemicity.
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| 3. |
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| 4. |
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| 5. |
- Björck, Lars, et al.
(author)
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On the interaction between beta 2-microglobulin and group A streptococci
- 1984
-
In: Scandinavian Journal of Immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 20:1, s. 69-79
-
Journal article (peer-reviewed)abstract
- beta 2-microglobulin (beta 2m) was found to interact with many group A streptococcal strains. The interaction appeared to require multipoint attachment, since monomeric beta 2m in solution showed no binding, whereas both beta 2m monomers bound to liposomes, and beta 2m in aggregates showed affinity for the bacteria. Aggregated HLA antigens (-A, -B and -C) and aggregated beta 2m exhibited the same binding patterns when tested in binding experiments with various group A streptococcal strains. Furthermore, beta 2m aggregates in excess completely blocked the binding of aggregated HLA antigens, thereby demonstrating that beta 2m is able to interact with streptococcal surface structures also when it is part of the HLA antigen complex. M protein-positive group A streptococcal strains bound significantly more beta 2m than M protein-negative variants of these strains. Purified M 12 protein partly inhibited the binding of radiolabelled beta 2m aggregates to whole streptococci, and in gel filtration and affinity chromatography experiments, the M 12 protein interacted with beta 2m. These various data suggest that the interaction between beta 2m and group A streptococci could be mediated by M protein. Lipoteichoic acid (LTA) is a constituent of the streptococcal cell wall that has been reported to form complexes with M protein at the bacterial cell surface. However, LTA did not influence the interaction between beta 2m and streptococci, suggesting that the binding of beta 2m to streptococcal M protein represents a pure protein-protein interaction. In vivo such an interaction could be established between infecting streptococci and host cells. Among 45 strains of different M types large differences in beta 2m binding were recorded, whereas among 60 strains of the classical nephritogenic M types 12 and 49, all were highly beta 2m-reactive, which points towards a role for beta 2m in streptococcal pathogenicity.
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| 6. |
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| 7. |
- Brimnes, J, et al.
(author)
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Reactions of N-N and N-O compounds with horseradish peroxidase and peroxidases from Mycobacterium tuberculosis
- 1999
-
In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - 1600-0463. ; 107:6, s. 555-565
-
Journal article (peer-reviewed)abstract
- Several N-N-and N-O-containing compounds were analysed for their ability to act as substrates for horseradish peroxidase and peroxidases in Mycobacterium tuberculosis extracts. Aminoguanidine, diaminoguanidine, isoniazid, hydroxylamine and hydrazine were found to be weak substrates for horseradish peroxidase in reaction I and to inhibit the reaction of horseradish peroxidase with hydrogen peroxide. The same compounds inhibited the reaction of Mycobacterium tuberculosis peroxidase-catalase with hydrogen peroxide, and hydroxylamine was found to be a weak substrate for this enzyme. In growth inhibition experiments, diaminoguanidine inhibited the growth of M. tuberculosis H37Rv at 50 microg/mL, but not the growth of two isoniazid-resistant strains. Isonicotinic acid hydroxamate inhibited the reaction of the peroxidases with hydrogen peroxide, but was not itself a substrate and had no growth-inhibitory effects. On the basis of these results we suggest that the effect of isoniazid on growth of M. tuberculosis results from increased oxidative stress due to inhibition of catalase-peroxidase as well as from generation of toxic radicals with the structure [structure in text].
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| 8. |
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| 9. |
- Gebre, Negussie, et al.
(author)
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Improved microscopical diagnosis of pulmonary tuberculosis in developing countries
- 1995
-
In: Transactions of the Royal Society of Tropical Medicine and Hygiene. - : Oxford University Press (OUP). - 1878-3503 .- 0035-9203. ; 89:2, s. 191-193
-
Journal article (peer-reviewed)abstract
- The diagnosis of pulmonary tuberculosis (TB) relies on the bacteriological examination of sputum. However, microscopy of smears made directly from sputum has a low sensitivity and there is an urgent need for improved methods. We have compared microscopy of smears made directly from sputum with microscopy after liquefaction of sputum with household bleach (NaOCl) and concentration of bacteria by centrifugation. In 3 studies performed in Ethiopia and India, the use of the NaOCl method increased the number of samples positive for acid-fast bacilli by more than 100%. The technique is appropriate for developing countries and its application would increase the efficiency of TB control programmes. As a potent disinfectant, NaOCl also has the advantage of lowering the risk of laboratory infection.
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| 10. |
- Holst, Elisabet, et al.
(author)
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In vitro activities of cefcanel and some other cephalosporins against Pasteurella multocida
- 1989
-
In: Antimicrobial Agents and Chemotherapy. - 1098-6596. ; 33:12, s. 2142-2143
-
Journal article (peer-reviewed)abstract
- Thirty-five strains of Pasteurella multocida from humans and animals were tested for susceptibility to five cephalosporins by a broth dilution method. Cefcanel showed high activity against all isolates (MIC and MBC, less than or equal to 0.64 micrograms/ml). The corresponding figure for cefaclor and cefuroxime was 2.56 micrograms/ml. Cefadroxil and cephalexin were the least active compounds tested.
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| 11. |
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| 12. |
- Larsson, Inger, et al.
(author)
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Interferon production in glia and glioma cell lines
- 1978
-
In: Infection and Immunity. - 1098-5522. ; 22:3, s. 786-789
-
Journal article (peer-reviewed)abstract
- Interferon (IF) was produced in glia and glioma cell lines in titers comparable to those produced by human fibroblasts. It was inducible by both Sendai virus and polyriboinosinic:polyribocytidylic acid. "Superinduction" resulted in up to 500-fold-higher titers of IF. The IF appeared to be of the fibroblast type, as revealed by experiments using heat treatment, assay of antiviral activity in heterologous cell lines, and neutralization with specific antisera. Since large amounts of IF may easily be produced with glioma cell lines, such cells may be suitable for mass production of IF.
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| 13. |
- Lorentzon, Siri, et al.
(author)
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The diagnosis of bacteriuria during pregnancy
- 1990
-
In: Scandinavian Journal of Primary Health Care. - : Informa UK Limited. - 0281-3432 .- 1502-7724. ; 8:2, s. 81-83
-
Journal article (peer-reviewed)abstract
- Three diagnostic tests, Nitur, Urobact, and Uricult, were evaluated in the detection of bacteriuria in 865 pregnant women. As reference method agar culture was performed. Heavy growth (greater than 10(5) CFU/ml) of urinary tract bacteria was considered a true positive result and demonstrated in 58 (6.7%) of the women, 14 of whom had gram-negative rods. The sensitivity of the nitrite test was extremely low (0.13). The test gave negative results in eight of 17 specimens yielding heavy growth of Escherichia coli or Proteus mirabilis. Although the Urobact test was highly sensitive as regards gram-negative infection, it had an unacceptably low (0.27) predictive value in positive tests. The sensitivity of the Uricult test was low (0.35) in this study. The predictive value (0.50) of a positive test result may be acceptable, since just over half of the false positive results were explainable by moderate growth of urinary tract pathogens (10(4)-10(5) CFU/ml). It is argued that semi-quantitative urine culture may be preferable to the rapid diagnostic methods studied for the screening of bacteriuria in pregnant women.
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| 14. |
- Lundgren, E, et al.
(author)
-
Effects of leukocyte and fibroblast interferon on events in the fibroblast cell cycle
- 1979
-
In: Journal of General Virology. - : Microbiology Society. - 1465-2099 .- 0022-1317. ; 42:3, s. 589-595
-
Journal article (peer-reviewed)abstract
- Serum-depleted human foetal skin fibroblasts were stimulated by addition of 10% foetal calf serum to proliferate synchronously for at least one cell cycle. This proliferation was suppressed by leukocyte or fibroblast interferon (IF), which prolonged the G1 phase and diminished the rate of DNA synthesis during the S phase in a dose-dependent manner. When used in identical concentration, as judged in terms of units of antiviral activity, fibroblast IF had more pronounced effects on cell cycle events than leukocyte IF. Interferon exerted its effect in early G1, before the cells were irreversibly committed to DNA synthesis.
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| 15. |
- Miörner, Håkan, et al.
(author)
-
30 år av framgångsrik mykobakterieforskning. AHRI i Addis Abeba unik forskningsmiljö i u-land
- 1999
-
In: Läkartidningen. - 0023-7205. ; 96:6, s. 585-587
-
Journal article (peer-reviewed)abstract
- The Armauer Hansen Research Institute (AHRI) in Addis Abeba, Ethiopia, was established by the Swedish and Norwegian Save the Children organisations in collaboration with the University of Bergen, with the principal objective of pursuing basic research in leprosy. The institute has a commendable record of achievement, and has made significant contributions to our understanding of leprosy and its control, and to the training of scientists from Ethiopia and other African countries. Recently, the Ethiopian, Swedish and Norwegian governments agreed to continue supporting the AHRI as an autonomous research centre. Its main objectives will be to conduct research in mycobacterial diseases, particularly tuberculosis, and to promote the enhancement of human resources in health research through instruction, supervision, and scientific collaboration.
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| 16. |
- Miörner, Håkan, et al.
(author)
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Assay of type-specific M antigens on whole group A streptococci
- 1984
-
In: European journal of clinical microbiology. - 0722-2211. ; 3:1, s. 14-18
-
Journal article (peer-reviewed)abstract
- A novel radioimmunoassay of type-specific M antigens on whole group A streptococcal cells is described. Absorbed rabbit anti-M antisera directed against M types 12 and 49 were used for determining M antigens on intact bacterial organisms. Staphylococcal protein A labelled with 125I was used as an anti-antibody reagent. The absorbed antisera were tested against ten homologous and 48 heterologous serotypes. All homologous serotypes gave an unequivocal reaction distinct from the weaker reaction with the heterologous serotypes. The type-specificity of the reaction was confirmed by the removal of type-specific antibodies after absorption to purified M protein coupled to Sepharose 4B. The results indicate that the described method is a simple and reliable technique for the recognition of M types of group A streptococci and offers a valuable tool for studies of M antigen in situ.
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| 17. |
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| 18. |
- Miörner, Håkan, et al.
(author)
-
Diagnosis of tuberculous meningitis: a comparative analysis of 3 immunoassays, an immune complex assay and the polymerase chain reaction
- 1995
-
In: Tubercle and Lung Disease. - : Elsevier BV. - 0962-8479. ; 76:5, s. 381-386
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: To compare 3 immunoassays, an immune complex assay, and an application of the polymerase chain reaction (PCR) for the diagnosis of tuberculous meningitis (TBM). MATERIAL: Cerebrospinal fluid (CSF) from 33 patients with TBM and from 34 control patients with infectious and non-infectious CNS diseases was analysed. RESULTS: The antibody immunoassays were either nonspecific or insensitive. However, detection of mycobacterial IgG immune complexes correlated strongly with infection, as they were detected in the CSF from 64% of the patients with TBM compared to only 3 (9%) of the control samples. PCR analysis, using Mycobacterium tuberculosis-specific oligonucleotide primers, also strongly correlated with infection, as DNA was amplified from 54% of the samples from patients with TBM, but from only 2 (6%) of the control samples. Both 'false positive' samples were also positive in the immune complex assay and came from 2 patients with otogenic brain abscesses. It is conceivable that these patients suffered from otogenic tuberculosis with secondary non-mycobacterial meningitis. When combining the immune complex assay with DNA-detection by PCR, 100% of the culture positive and 74% of culture negative samples were found to be positive, while maintaining a high specificity. CONCLUSION: Parallel analysis to detect mycobacterial immune complexes and M. tuberculosis-specific DNA by PCR from the CSF of patients may offer a sensitive and specific tool for the diagnosis of TBM.
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| 19. |
- Miörner, Håkan, et al.
(author)
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Effect of specific binding of human albumin, fibrinogen, and immunoglobulin G on surface characteristics of bacterial strains as revealed by partition experiments in polymer phase systems
- 1980
-
In: Infection and Immunity. - 1098-5522. ; 29:3, s. 879-885
-
Journal article (peer-reviewed)abstract
- Four strains of gram-positive cocci with different combinations of positive binding of human proteins were investigated with respect to changes in physicochemical surface properties after specific protein binding. Staphylococcus aureus Cowan I, two group A beta-hemolytic streptococci, and one group G streptococcal strain were studied; they represented three different combinations of reactivity for human serum albumin, human immunoglobulin G, and fibrinogen. Using single-tube partition of bacterial cells in a dextran-polyethylene glycol system of constant polymer concentration but varying ionic compositions, it was possible to detect changes in the partition of bacteria after specific protein binding. There was a correlation between the binding of radiolabled human proteins to the bacterial strains and the effect of human proteins on the partition of the bacteria in the phase systems. Thus, the specific binding of proteins to the bacteria changes their physicochemical surface properties. These types of bacteria-protein interactions may play an important role in modulating host-parasite relationships.
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| 20. |
- Miörner, Håkan, et al.
(author)
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Improved isolation of mycobacteria other than Mycobacterium tuberculosis on isoniazid-containing Lowenstein-Jensen medium
- 1988
-
In: European Journal of Clinical Microbiology & Infectious Diseases. - 1435-4373. ; 7:1, s. 47-49
-
Journal article (peer-reviewed)abstract
- The benefit of including isoniazid-containing Lowenstein-Jensen medium for primary isolation of mycobacteria was evaluated in 3,726 clinical specimens. This media increased the primary isolation of mycobacteria other than Mycobacterium tuberculosis by 9.2%, facilitated macroscopical reading and aided presumptive identification of the isolated mycobacteria.
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| 21. |
- Miörner, Håkan, et al.
(author)
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Isoelectric points and surface hydrophobicity of Gram-positive cocci as determined by cross-partition and hydrophobic affinity partition in aqueous two-phase systems
- 1982
-
In: Infection and Immunity. - 1098-5522. ; 36:1, s. 227-234
-
Journal article (peer-reviewed)abstract
- Thirty-nine streptococcal strains belonging to groups A, C, and G and 12 staphylococcal strains were investigated with respect to surface charge and hydrophobicity. Isoelectric points of the bacteria were determined by cross-partition experiments in dextran-polyethylene glycol two-phase systems containing charged polymers. The results obtained indicate that group A, C, and G streptococci have isoelectric points of pH 3.75 +/- 0.15 standard deviation. Staphylococci show an isoelectric point of around pH 2 and thereby differ markedly from the streptococci. Pretreatment of bacteria with human serum resulted in a significant change in the isoelectric points of streptococci. In a second series of experiments, an aqueous dextran-polyethylene glycol two-phase system containing polyethylene glycol palmitate or stearate was used to study the hydrophobic surface properties of the bacterial cells. The partition of the staphylococci was not influenced by the addition of up to 1% (wt/wt) polyethylene glycol palmitate or stearate, whereas the streptococci showed a large variation in affinity for polyethylene glycol-bound hydrophobic groups. The bacterial strains included in the study were also tested for uptake of human serum proteins. A positive correlation was found between the hydrophobic affinity of group A streptococci and the density of receptors for aggregated beta-2-microglobulin.
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| 22. |
- Miörner, Håkan, et al.
(author)
-
Lipoteichoic acid is the major cell wall component responsible for surface hydrophobicity of group A streptococci
- 1983
-
In: Infection and Immunity. - 1098-5522. ; 39:1, s. 336-343
-
Journal article (peer-reviewed)abstract
- The contribution of lipoteichoic acid (LTA) to the hydrophobic surface properties of group A streptococci was investigated in aqueous dextran-polyethylene glycol two-phase systems. Enzymatic digestions were performed to characterize the hydrophobic surface structure. The results obtained indicated that LTA is a major factor responsible for the hydrophobic character of the cell surface of group A streptococci. This was further supported by the similarity of partition in polymer two-phase systems between whole group A streptococci and tritiated LTA extracted from a group A streptococcal strain. Surface LTA was also determined on intact organisms by a new method measuring the adsorption of antibodies to LTA to the bacterial surface. A correlation was found between the content of surface LTA and the hydrophobicity of the group A streptococci. We conclude that surface-associated LTA is the major factor determining surface hydrophobicity of group A streptococci.
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| 23. |
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| 24. |
- Miörner, Håkan, et al.
(author)
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Regulation of mitogen-induced lymphocyte DNA synthesis by human interferon of different origins
- 1978
-
In: Cellular Immunology. - : Elsevier BV. - 0008-8749. ; 35:1, s. 15-24
-
Journal article (peer-reviewed)abstract
- Human fibroblast and leukocyte interferons were found to suppress lymphocyte mitogenesis induced by optimal doses of phytohemagglutinin and concanavalin A. In certain situations (low doses of mitogen and/or low doses of interferon), however, interferon significantly enhanced mitogenesis. In experiments using varying concentrations of interferon, dose-response curves with different slopes were obtained for fibroblast and leukocyte interferons. The effect of interferon was apparently exerted during early stages of the lymphocyte cell cycle. There was no inhibitory effect of interferon if the lymphocytes were washed with medium before being exposed to mitogen. Interferon increased the binding of radiolabeled mitogens to cells. The results suggest that the immunological effects of interferon are consequences of actions on lymphoid cells. Fibroblast and leukocyte interferons seem to have different modes of action, or to bind differently to target cells. Possible mechanisms for the suppressive and enhancing effects of interferons on lymphoid cells are discussed.
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| 25. |
- Miörner, Håkan, et al.
(author)
-
Surface characteristics of group A streptococci with and without M-protein
- 1984
-
In: Acta pathologica, microbiologica, et immunologica Scandinavica. Section B, Microbiology. - 0108-0180. ; 92:1, s. 23-30
-
Journal article (peer-reviewed)abstract
- Twenty M protein-positive and eight M protein-negative strains of group A streptococci were investigated with respect to surface hydrophobicity and amount of lipoteichoic acid (LTA). Surface hydrophobicity as determined in polymer two-phase systems varied substantially between individual strains and there was no correlation to the presence of antiphagocytic M protein. The amount of LTA on the surface of the bacteria varied with hydrophobic affinity of the cells. Strains with a high content of surface LTA were found among both M-positive and M-negative streptococci. Cellular and extracellular LTA was estimated on six strains by the ability of hot phenol extracts and culture fluids to sensitize erythrocytes and by rocket immunoelectrophoretic quantitation. Differences in content of surface LTA did not correlate to differences in the total amount of cellular LTA. Pepsin digestion of M-positive group A streptococci at suboptimal pH resulted in a loss of M antigen whereas surface LTA and the hydrophobic interaction liability was retained. The results indicate that the degree of surface hydrophobicity as measured by two-phase partitioning is not correlated to either the type-specific or the antiphagocytic moiety of M protein. The results support the correlation between surface LTA and surface hydrophobicity of group A streptococci.
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| 26. |
- Olsson-Liljequist, B, et al.
(author)
-
Antimicrobial susceptibility testing in Sweden. III. Methodology for susceptibility testing
- 1997
-
In: Scandinavian Journal of Infectious Diseases. Supplementum. - 0300-8878. ; 105, s. 13-23
-
Journal article (peer-reviewed)abstract
- A subcommittee of the Swedish Reference Group for Antibiotics, SRGA-M, has worked with standardization of methodology for susceptibility testing. In vitro data obtained with the disk diffusion procedure were collected from 5 clinical laboratories, compiled and presented as histograms of inhibition zones, and compared with data [minimum inhibitory concentrations (MICs) and inhibition zones] obtained from the reference laboratory at the Swedish Institute for Infectious Disease Control on a collection of clinically relevant bacterial species. Results from the reference collection of strains were presented as MIC histograms, and their corresponding inhibition zones were inserted in the compiled zone histograms as identifiable bars. These distributions formed the basis for decisions of breakpoints. Special tests were recommended for the detection of certain resistance mechanisms. A beta-lactamase test should be used for Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae and enterococci. Screening for beta-lactam resistance caused by altered penicillin binding proteins should be done by using oxacillin 1 microgram for Streptococcus pneumoniae and Staphylococcus aureus (MRSA), and by phenoxymethylpenicillin 10 micrograms for H, influenzae. The standardized disk diffusion procedure was helpful in detecting enterobacteria carrying beta-lactamases with extended spectra. Registration of inhibition zones will provide a powerful tool for the epidemiological surveillance of antibiotic resistance.
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| 27. |
- Petersson, Ann Cathrine, et al.
(author)
-
Disk with high oxacillin content discriminates between methicillin-resistant and borderline methicillin-susceptible Staphylococcus aureus strains in disk diffusion assays using a low salt concentration
- 1999
-
In: Journal of Clinical Microbiology. - 1098-660X. ; 37:6, s. 2047-2050
-
Journal article (peer-reviewed)abstract
- A separation between mecA+ strains of Staphylococcus aureus and strains lacking mecA was achieved by the disk diffusion assay and the agar dilution method, utilizing disks containing 5 microg of oxacillin and inocula of approximately 5 x 10(5) CFU/spot, respectively, provided that agar with 0 to 0.5% NaCl and incubation at 30 degrees C were employed. The 5-microg oxacillin disks clearly discriminated between borderline methicillin-susceptible and mecA+ strains. The oxacillin MICs were more affected by the inoculum density and salt concentration than were the methicillin MICs, and oxacillin MICs of 4 to 16 microg/ml were obtained for strains lacking mecA. Significantly higher levels of beta-lactamase production and reduced oxacillin susceptibilities were recorded for strains lacking mecA, in particular strains of phage group V, when agar with >/=2% NaCl was used than when agar with 0 to 0.5% NaCl was employed. The results indicate that the borderline methicillin-susceptible phenotype is a salt-dependent in vitro phenomenon of questionable clinical relevance.
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| 28. |
- Petersson, A C, et al.
(author)
-
Evaluating the usefulness of spa typing, in comparison with pulsed-field gel electrophoresis, for epidemiological typing of methicillin-resistant Staphylococcus aureus in a low-prevalence region in Sweden 2000-2004.
- 2010
-
In: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 16, s. 456-462
-
Journal article (peer-reviewed)abstract
- Clin Microbiol InfectAbstract The usefulness of spa typing was evaluated in relation to pulsed-field gel electrophoresis (PFGE), as a tool for epidemiological typing of methicillin-resistant Staphylococcus aureus (MRSA) in a low-prevalence region in southern Sweden. Bacterial isolates from 216 MRSA cases, newly identified in 2000-2004, were studied. The isolates were obtained from infected patients (31%), and from colonized individuals found by screening (69%). In total, 49 spa types and 73 PFGE patterns were identified. The discriminatory power of spa typing was lower (94.9 +/- 1.8%) than that of PFGE (97.3 +/- 1.2%). For two spa types (t002 and t008) the Panton-Valentine leukocidin results added useful discriminatory information. The most common spa types were t044 (n = 31; four PFGE patterns), t002 (n = 24; 10 PFGE patterns), t067 (n = 12; four PFGE patterns), t050 (n = 12; one PFGE pattern), and t324 (n = 11; one PFGE pattern). Epidemiological investigations identified 91 single cases and 39 transmission chains, each involving two to 13 cases. All the transmission chains were held together both by spa and PFGE typing. Among the 91 single-case isolates, 33 spa types and 50 PFGE patterns were unique (matchless) at the time of identification. The low prevalence of MRSA, the low number of outbreaks, and the wide spectrum of strains due to frequent acquisitions abroad (49% of the cases), makes spa typing a useful complement to epidemiological investigations in our setting. However, we still recommend the continued use of PFGE for further discrimination of isolates with identical spa types when epidemiological data can not exclude possible transmission.
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| 29. |
- Petersson, A C, et al.
(author)
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Evaluation of four qualitative methods for detection of beta-lactamase production in Staphylococcus and Micrococcus species
- 1989
-
In: European Journal of Clinical Microbiology & Infectious Diseases. - 1435-4373. ; 8:11, s. 962-967
-
Journal article (peer-reviewed)abstract
- Four qualitative methods for the detection of beta-lactamase production in Staphylococcus and Micrococcus species were evaluated and compared with a quantitative macroiodometric reference method. The disc diffusion test with penicillin G and the cloverleaf method could not separate beta-lactamase-positive from beta-lactamase-negative strains. Two applications of the chromogenic cephalosporin test, using uninduced strains and strains grown on blood agar plates, gave a large number of false negative and false positive results. False negative reactions were most common among uninduced strains, while the false positive reactions were most often recorded for Staphylococcus saprophyticus. A high degree of efficiency was recorded for the nitrocefin spot test, using induced strains grown on antibiotic susceptibility agar, and for the starch-iodine plate method. The starch-iodine plate with methicillin as inducer gave the most reliable results.
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| 30. |
- Petersson, A C, et al.
(author)
-
Identification of mecA-related oxacillin resistance in staphylococci by the E test and the broth microdilution method
- 1996
-
In: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 1460-2091 .- 0305-7453. ; 37:3, s. 445-456
-
Journal article (peer-reviewed)abstract
- A set of 165 strains of different staphylococcal species, 67 Staphylococcus aureus, 71 novobiocin-sensitive coagulase-negative staphylococci (CNS) and 27 novobiocin-resistant CNS was used. The oxacillin and methicillin MICs were recorded after 24 and 42 h of incubation at 35 degrees C and at 30 degrees C. Significantly higher MICs were recorded at 30 degrees C compared with 35 degrees C. While a poor discrimination between mecA-positive and mecA-negative strains was obtained with methicillin, the oxacillin MICs enabled identification of resistant strains under certain conditions. The distribution of MICs differed between the three groups of species. Separation of uninduced mecA-positive (> or = 4.0 mg oxacillin/L) and mecA-negative (< or = 2.0 mg oxacillin/L) strains of S. aureus was only achieved with the E test and after 42 h of incubation. Oxacillin-induction yielded higher MICs for mecA-positive strains of S. aureus, and a separation from mecA-negative strains was achieved with the E test after 24 h and with the broth microdilution method after 42 h. Separation of mecA-positive and mecA-negative strains of novobiocin-sensitive CNS required agar supplemented with 5% blood, incubation of MIC trays and E test for 42 h, and species-specific oxacillin MIC breakpoints (S < or = 0.5 mg/L and R > or = 1.0 mg/L). The mecA-positive and mecA-negative strains of novobiocin-resistant CNS were clearly separated after 24 h of incubation by either method.
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| 31. |
- Petersson, A C, et al.
(author)
-
Species-specific identification of methicillin resistance in staphylococci
- 1995
-
In: European Journal of Clinical Microbiology & Infectious Diseases. - 1435-4373. ; 14:3, s. 206-211
-
Journal article (peer-reviewed)abstract
- The ability to identify methicillin-resistant staphylococci by the disc diffusion method was evaluated using discs containing oxacillin (1, 5 and 10 micrograms), methicillin (10 micrograms) and cephalexin (30 micrograms). Strains of Staphylococcus aureus (67 strains) and coagulase-negative staphylococci (72 novobiocin-sensitive and 27 novobiocin-resistant strains) were studied using two inoculum densities (10(6) cfu/ml and 10(8) cfu/ml). Inhibitory zones were recorded after 18, 24 and 42 hours of incubation. A mecA-specific application of the polymerase chain reaction was used as a reference method. The inoculum of 10(8) cfu/ml and incubation for 24 hours were optimal for the identification of methicillin-resistant strains. However, one single disc was not sufficient for the identification of methicillin resistance in the different staphylococcal species. The mecA-positive strains of Staphylococcus aureus and novobiocin-resistant coagulase-negative species were clearly separated from the mecA-negative strains when the 5 micrograms oxacillin disc was used, whereas the 1 microgram oxacillin disc was optimal for the identification of the mecA-positive novobiocin-sensitive coagulase-negative strains.
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| 32. |
- Poulsen, S, et al.
(author)
-
Tuberkuloseudviklingen i Danmark 1972-1996
- 1999
-
In: Ugeskrift for Læger. - 0041-5782. ; 161:23, s. 3452-3457
-
Journal article (peer-reviewed)abstract
- The present study is based on notified cases of tuberculosis (TB) in the National tbc. register 1972-1996. A decline in Tb incidence was seen from 1972 and until the mid-1980's. Subsequently the trend has reversed due to an increasing number of TB cases in foreigners. In 1996, 60% of all cases of TB in Denmark were found in foreigners reflecting the rising number of refugees and their families arriving in Denmark from highly endemic areas, mainly Somalia. Among native Danes the TB incidence fell from 14 per 100,000 in 1972 to 4 per 100,000 in the 1980's and stabilized at this very low level. The unchanged incidence in Danes covers a falling incidence in the older and a rising incidence in the younger and middle-aged adult population, mainly in the capital. Approximately half of the cases occur in high-risk groups. The TB-epidemic is close to elimination in the indigenous Danish population, but the disease is maintained at a low level probably due to increased patient and doctor delay and resulting microepidemics primarily in high-risk populations.
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| 33. |
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| 34. |
- Reutersward, A, et al.
(author)
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Variations in binding of mammalian fibrinogens to streptococci groups A, B, C, E, G and to Staphylococcus aureus
- 1985
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In: Acta pathologica, microbiologica, et immunologica Scandinavica. Section B, Microbiology. - 0108-0180. ; 93:2, s. 77-82
-
Journal article (peer-reviewed)abstract
- Twenty-eight beta-hemolytic streptococci of groups A, B, E, G and Streptococcus equisimilis as well as four Staphylococcus aureus strains were tested for their ability to bind fibrinogen preparations from different animal species: homo, baboon, rabbit, rat, guinea-pig, dog, horse, pig, cow and sheep. The patterns of binding indicated differences in the structures of the bacterial fibrinogen receptors. There were higher binding levels in streptococci groups A, G, and S. equisimilis than in representative group B and E strains. Considerable differences in the binding capacity were found within streptococci groups A and E. Group C and group G strains showed rather similar patterns and could be further divided into high-level and low-level binding strains. There is no correlation between binding levels of different animal fibrinogen preparations and the strains isolated from corresponding animals. Recent studies by others have shown that resistance to phagocytosis is mediated by fibrinogen-binding in streptococci group A. The existence of similar fibrinogen-binding structures in several streptococcal species indicates an important role with a definite survival value. It also suggests that M or T protein analogues are present in streptococci groups C, G and E.
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| 35. |
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| 36. |
- Rydberg, Johan, et al.
(author)
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Assessment of a possible imbalance between tumor necrosis factor (TNF) and soluble TNF receptor forms in tuberculous infection of the central nervous system
- 1995
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In: Journal of Infectious Diseases. - 1537-6613. ; 172:1, s. 301-304
-
Journal article (peer-reviewed)abstract
- Distributions of tumor necrosis factor (TNF) and its soluble receptor forms, R55-BP and R75-BP, were analyzed in the cerebrospinal fluid of patients with severe acute or chronic central nervous system infections. Tuberculous infections were associated with high ratios of R55-BP and R75-BP to TNF, 27.2 and 28.0, respectively, suggesting a small biologically active fraction of TNF. The opposite was found in subjects with acute bacterial meningitis. They had large fractions of biologically active TNF and thus low ratios of R55-BP and R75-BP to TNF, 3.7 and 4.0, respectively. It is hypothesized that chronic infectious diseases, such as tuberculous infections, may be associated with inadequate production of TNF and a concomitant relative increase of soluble TNF receptors, which may prolong the disease.
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| 37. |
- Rydberg, Johan, et al.
(author)
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Resistance to fluoroquinolones in Pseudomonas aeruginosa and Klebsiella pneumoniae
- 1994
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In: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 26:3, s. 317-320
-
Journal article (peer-reviewed)abstract
- The fluoroquinolone sensitivity of Pseudomonas aeruginosa and Klebsiella pneumoniae was studied by determinations of Minimum Inhibitory Concentrations (MICs) of norfloxacin and ciprofloxacin in consecutive clinical isolates. In P. aeruginosa, resistance or reduced susceptibility (MIC > or = 8 mg/l for norfloxacin and > or = 2 mg/l for ciprofloxacin) was found in 17% (9/54) of the isolates. Reduced susceptibility (MIC > or = 2 mg/l for norfloxacin) was found in 12% (10/84) of K. pneumoniae isolates. P. aeruginosa strains isolated in 1991 had reduced susceptibility to both norfloxacin and ciprofloxacin significantly more often than isolates from 1984-85 (p = 0.02). 10/84 K. pneumoniae strains from 1991 had reduced susceptibility to norfloxacin, compared with 1/34 from 1984-85. This difference was not statistically significant (p = 0.11).
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| 38. |
- Savic, B, et al.
(author)
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Evaluation of polymerase chain reaction, tuberculostearic acid analysis, and direct microscopy for the detection of Mycobacterium tuberculosis in sputum
- 1992
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In: Journal of Infectious Diseases. - 1537-6613. ; 166:5, s. 1177-1180
-
Journal article (peer-reviewed)abstract
- Tuberculosis remains a major global cause of morbidity and mortality. There is an urgent need for improved bacteriologic diagnosis of Mycobacterium tuberculosis infection. Three methods for rapid identification of M. tuberculosis in sputum samples (direct microscopy, gas chromatography-mass spectrometry [GC-MS], and polymerase chain reaction [PCR]), were compared with culture on Lowenstein-Jensen medium. Growth of M. tuberculosis was observed in 38 of 145 sputum samples. Detection of acid-fast bacilli by direct microscopy gave a sensitivity of 66% and a specificity of 100%. Detection of tuberculostearic acid by GC-MS gave a sensitivity of 55% and a specificity of 87%. Amplification by PCR of a fragment of the insertion sequence IS6110 gave a sensitivity of 95% and a specificity of 93% compared with culture and a corrected specificity of 99% compared with both culture and clinical data. This study indicates that PCR can be adapted for clinical use and is the method of choice for rapid diagnosis of pulmonary tuberculosis.
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| 39. |
- Schalén, Lucyna, et al.
(author)
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High isolation rate of Branhamella catarrhalis from the nasopharynx in adults with acute laryngitis
- 1980
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In: Scandinavian Journal of Infectious Diseases. - 1651-1980. ; 12:4, s. 277-280
-
Journal article (peer-reviewed)abstract
- Branhamella catarrhalis was isolated from the nasopharynx in 55% of 40 noncompromised adult patients suffering from acute laryngitis. Diplococcus pneumoniae and haemophilus influenzae were found in another 5 and 8%, respectively; one patient had group A streptococci in the throat specimen. In 90% of the patients the laryngitis complaints were preceded by symptoms of an acute respiratory tract infection. Two of the patients with B. catarrhalis showed a significant titre conversion against influenza B and parainfluenza type e virus, respectively. Attempts to isolate virus failed in all cases. The results indicate that B. catarrhalis, known to cause acute otitis media in small children and respiratory tract infections in adult compromised hosts, may be involved in the etiology of acute laryngitis in otherwise healthy adults.
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| 40. |
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| 41. |
- Sjöbring, Ulf, et al.
(author)
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Polymerase chain reaction for detection of Mycobacterium tuberculosis
- 1990
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In: Journal of Clinical Microbiology. - 1098-660X. ; 28:10, s. 2200-2204
-
Journal article (peer-reviewed)abstract
- A polymerase chain reaction for the specific detection of mycobacteria belonging to the Mycobacterium tuberculosis complex was developed. Using a single primer pair derived from the nucleotide sequence of protein antigen b of M. tuberculosis, we achieved specific amplification of a 419-base-pair DNA fragment in M. tuberculosis and M. bovis. After DNA was extracted from mycobacteria by using a simple, safe lysis procedure, we detected the 419-base-pair sequence in samples containing few mycobacteria. Preliminary data suggested that this technique could be applied to clinical specimens for early and specific diagnosis of tuberculosis.
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| 42. |
- Skarin, Angelika, et al.
(author)
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Acanthamoeba keratitis in the south of Sweden
- 1996
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In: Acta Ophthalmologica Scandinavica. - 1395-3907. ; 74:6, s. 593-597
-
Journal article (peer-reviewed)abstract
- Eight patients with Acanthamoeba keratitis were diagnosed and treated at our clinic between February 1991 and February 1993. Five of these were contact lens wearers, two had suffered recent corneal trauma and one had recently undergone penetrating keratoplasty. The diagnoses were based on both culture and histological examination of biopsy material in three cases, on culture alone in two cases and on histological examination alone in three cases. In all but one primary treatment was Propamidine isethionate and Neomycin/Polymyxin B topically and Ketoconazole orally. Because of poor healing three patients additionally received Paromomycin and Miconazole or Clotrimazol topically; two of these were further treated with Polyhexamethylene biguanide topically. The interval from initial symptoms to accurate diagnoses varied from one to eleven months. In one patient the eye could not be saved; in the remaining patients visual acuity after healing ranged from hand movements to 1.0.
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| 43. |
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| 44. |
- Stender, H, et al.
(author)
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Fluorescence In situ hybridization assay using peptide nucleic acid probes for differentiation between tuberculous and nontuberculous mycobacterium species in smears of mycobacterium cultures
- 1999
-
In: Journal of Clinical Microbiology. - 1098-660X. ; 37:9, s. 2760-2765
-
Journal article (peer-reviewed)abstract
- TB PNA FISH is a new fluorescence in situ hybridization (FISH) method using peptide nucleic acid (PNA) probes for differentiation between species of the Mycobacterium tuberculosis complex (MTC) and nontuberculous mycobacteria (NTM) in acid-fast bacillus-positive (AFB+) cultures is described. The test is based on fluorescein-labelled PNA probes that target the rRNA of MTC or NTM species applied to smears of AFB+ cultures for microscopic examination. Parallel testing with the two probes serves as an internal control for each sample such that a valid test result is based on one positive and one negative reaction. TB PNA FISH was evaluated with 30 AFB+ cultures from Denmark and 42 AFB+ cultures from Thailand. The MTC-specific PNA probe showed diagnostic sensitivities of 84 and 97%, respectively, and a diagnostic specificity of 100% in both studies, whereas the NTM-specific PNA probe showed diagnostic sensitivities of 91 and 64%, respectively, and a diagnostic specificity of 100% in both studies. The low sensitivity of the NTM-specific PNA probe in the Thai study was due to a relatively high prevalence of Mycobacterium fortuitum, which is not identified by the probe. In total, 63 (87%) of the cultures were correctly identified as MTC (n = 46) or NTM (n = 17), whereas the remaining 9 were negative with both probes and thus the results were inconclusive. None of the samples were incorrectly identified as MTC or NTM; thus, the predictive value of a valid test result obtained with TB PNA FISH was 100%.
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| 45. |
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| 46. |
- Strannegård, Örjan, et al.
(author)
-
Modulation of immune responses in newborn and adult mice by interferon
- 1978
-
In: Infection and Immunity. - 1098-5522. ; 20:2, s. 334-339
-
Journal article (peer-reviewed)abstract
- Interferon was found to have both suppressive and enhancing effects on the antibody response in newborn and adult mice. Evidence was obtained that these effects are primarily evoked during the initial steps controlling cell proliferation. Stimulation of thymus and spleen cells with a T-cell mitogen was enhanced by low doses and suppressed by high doses of interferon. Treatment of parental spleen cells with interferon before injecting them into immunized F1 hybrid mice resulted in an enhanced allogeneic effect. These results are compatible with the hypothesis that interferon affects T cells and has an immunoregulatory role, either by inhibiting the action of suppressor cells or by promoting immunological maturation.
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| 47. |
- Sundbeck, Mats, et al.
(author)
-
Sexual risk-taking during travel abroad - a cross-sectional survey among youth in Q2 Sweden
- 2016
-
In: Travel Medicine and Infectious Disease. - : Elsevier BV. - 1477-8939 .- 1873-0442. ; 14:3, s. 233-241
-
Journal article (peer-reviewed)abstract
- Summary Background: The aim was to assess sexual risk-taking behaviour in a sample of Swedish youth who were sexually active while travelling abroad and to examine possible associations with sexual risk-taking behaviour during such travel.Methods: From a population-based sample of 2189 Swedes 18e29 years 768 who were sexually active while abroad, were assessed by a questionnaire concerning socio-demographic background, life-style, travel duration, sexuality, mental health, heavy episodic drinking (HED) and drug-use.Results: Approximately 1/4 reported intercourse with a casual partner abroad. Casual sex was associated with HED, 18e24 years, and drug use in both sexes, and for women, also with one month of travel. Among youth with casual partners, 48% reported non-condom use. Noncondom use with a casual partner was associated with 18e24 years, one month of travel for women, and poor self-rated mental health for men. About 10% had 2 partners abroad. Having 2 partners abroad was associated with one month of travel, and for men also with HED.Conclusion: Male sex, 18e24 years of age, 1 month of travel, HED, and drug use were significantly associated with sexual risk-taking during travel abroad. Poor self-rated mental health and foreign-born parentage might also constitute risk factors for men.
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| 48. |
- Thomsen, Vibeke O, et al.
(author)
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Incidence and clinical significance of non-tuberculous mycobacteria isolated from clinical specimens during a 2-y nationwide survey
- 2002
-
In: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 34:9, s. 648-653
-
Journal article (peer-reviewed)abstract
- A 2-y nationwide survey of patients in Denmark with non-tuberculous mycobacteria (NTM) cultures was undertaken. Patients were identified by means of records held at the International Reference Laboratory of Mycobacteriology, Statens Serum Institut, Denmark. The objectives were to identify isolated NTM to species level, to describe the incidence of the various species and to evaluate the clinical significance of pulmonary NTM isolates other than M. avium complex (MAC) and M. gordonae. Identification was performed by means of hybridization or sequencing of 16S rDNA. The clinical significance of pulmonary NTM isolates was evaluated by means of questionnaires concerning patients (was sent to the clinicians!) patients who had NTM isolated for the first time using bacteriologic, radiographic and clinical criteria. A total of 1110 specimens (2.1%) from 525 patients grew NTM. After MAC (n = 198) and M. gordonae (n = 168), most patients had M. abscessus (n = 21), M. malmoense (n = 20) and M. xenopi (n = 17) isolated. Of the pulmonary patients, 50.6% met bacteriologic criteria, 75.3% radiographic criteria and 53.4% clinical criteria for significant infection. Almost half of the pulmonary patients met all the criteria for significant NTM infection that could be evaluated. Clinically significant infection was associated with underlying disease in most patients.
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| 49. |
- Törös, Bianca, 1987-
(author)
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Genome-based characterization of Neisseria meningitidis with focus on the emergent serogroup Y disease
- 2014
-
Doctoral thesis (other academic/artistic)abstract
- Neisseria meningitidis, also referred to as meningococcus, is one of the leading causes of epidemic meningitis and septicaemia worldwide. Despite modern treatment, meningococcal disease remains associated with a high mortality (about 10%). Meningococcal disease is mainly restricted to specific hypervirulent lineages and specific capsular groups (serogroups), which have a changing global distribution over time. At the end of the 2000s, the previously unusual serogroup Y emerged, corresponding to half of all of the invasive meningococcal disease (IMD) cases in Sweden by the beginning of the 2010s. The aim of this thesis is to describe the emergence of serogroup Y meningococci genetically in an effort to understand some of the factors involved in the successful spread of this group throughout Sweden. In addition, genetic typing schemes were evaluated for surveillance and outbreak investigation.Our results indicate that the currently recommended typing for surveillance of meningococci could be altered to include the factor H-binding protein (fHbp). A highly variable multilocus variable number tandem repeat analysis (HV-MLVA) was able to confirm connected cases in a suspected small outbreak. In addition, a strain type sharing the same porA, fetA, porB, fHbp, penA and multilocus sequence type was found to be the principal cause of the increase in serogroup Y disease. However, a deeper resolution obtained from the core genomes revealed a subtype of this strain, which was mainly responsible for the increase. Finally, when the Swedish serogroup Y genomes were compared internationally, different strains seemed to dominate in different regions. This indicates that the increase was probably not due to one or more point introductions of a strain previously known internationally but more probably multifactorial.
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| 50. |
- Winqvist, Niclas, et al.
(author)
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Long-term course of Mycobacterium tuberculosis infection in Swedish birth cohorts during the twentieth century.
- 2011
-
In: The International Journal of Tuberculosis and Lung Disease. - : International Union Against Tuberculosis and Lung Disease. - 1815-7920 .- 1027-3719. ; 15:6, s. 736-740
-
Journal article (peer-reviewed)abstract
- Abstract SETTING: Sweden under transition from high to low tuberculosis (TB) incidence from 1920 to 2009. OBJECTIVE: To correlate estimates of TB infection in birth cohorts with the longitudinal incidence of active TB to assess the long-term risk and time pattern of reactivated TB. DESIGN: Time trend analysis on TB incidence using age-cohort modelling. RESULTS: The overall TB incidence decreased from 700 per 100 000 population in 1920 to 1.4 in 2009 in the Sweden-born population. The estimated disease rate (number of cases divided by the estimated number of infected in 1967), for each birth cohort between 1920 and 1940, was stable on a level between 9.8% and 10.7%. The reactivation rate of latent TB infection (LTBI) was 2% after 1967, when indigenous transmission had disappeared. CONCLUSION: Although approximately 10% of persons with LTBI developed active TB, the majority of cases occurred shortly after infection, and the rates of reactivation declined over time. This indicates extensive spontaneous clearance of LTBI
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