PubMed Health⌕ Search

Biomedical subjects

H Miörner

Publications and source records attributed to H Miörner.

At least 37 records · Page 2Linked to original sources
PubMed1995

Species-specific identification of methicillin resistance in staphylococci.

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.

Anti-Bacterial Agents↗
PubMed1995

Diagnosis of tuberculous meningitis: a comparative analysis of 3 immunoassays, an immune complex assay and the polymerase chain reaction.

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.

Adolescent↗
PubMed1995

Assessment of a possible imbalance between tumor necrosis factor (TNF) and soluble TNF receptor forms in tuberculous infection of the central nervous system.

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.

Acute Disease↗
PubMed1994

Resistance to fluoroquinolones in Pseudomonas aeruginosa and Klebsiella pneumoniae.

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).

Anti-Infective Agents↗
PubMed1993

Bronchoscopic diagnosis of pulmonary infections in a heterogeneous, nonselected group of patients.

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.

AIDS-Related Opportunistic Infections↗
PubMed1992

Evaluation of polymerase chain reaction, tuberculostearic acid analysis, and direct microscopy for the detection of Mycobacterium tuberculosis in sputum.

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.

Base Sequence↗
PubMed1990

Polymerase chain reaction for detection of Mycobacterium tuberculosis.

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.

Base Sequence↗
PubMed1990

The diagnosis of bacteriuria during pregnancy.

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.

Agar↗
PubMed1989

Evaluation of four qualitative methods for detection of beta-lactamase production in Staphylococcus and Micrococcus species.

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.

Bacteriological Techniques↗