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L Matas

Publications and source records attributed to L Matas.

At least 55 records · Page 3Linked to original sources
PubMed1998

Comparative evaluation of two commercial assays for direct detection of Mycobacterium tuberculosis in respiratory specimens.

Two commercial systems for the amplification and detection of Mycobacterium tuberculosis directly from respiratory samples were compared. The Roche Cobas Amplicor MTB Test and the Roche manual Amplicor MTB Test (Roche Diagnostic Systems, USA) were applied to 755 decontaminated respiratory specimens collected from 470 patients. Results were compared with those of acid-fast staining and culture. A total of 251 specimens were collected from 156 patients diagnosed with pulmonary tuberculosis, including 28 specimens corresponding to 13 patients that were receiving antituberculous treatment. Given the overall positivity rate of 33.2% (251/755), the sensitivity, specificity, and positive and negative predictive values were 92.4, 100, 100, and 96.5%, respectively, for the Cobas Amplicor MTB Test and 90.8, 100, 100, and 95.8%, respectively, for the Amplicor MTB Test. For 204 (81.3%) smear positive specimens and 47 (19.7%) smear negative specimens, the sensitivity values were 100 and 59.6%, respectively, for the Cobas Amplicor MTB Test and 100 and 51%, respectively, for the Amplicor MTB Test. There were no statistically significant differences in sensitivity or specificity between the two assays and culture (p>0.05). The overall results of both assays were concordant for 99.5% of the samples. It is concluded that although both nucleic acid amplification methods are rapid and specific for the detection of Mycobacterium tuberculosis complex in respiratory specimens, the Cobas Amplicor MTB Test appears to be slightly more sensitive than the Amplicor MTB Test when smear negative specimens are investigated.

Evaluation Studies as Topic↗
PubMed1998

Evaluation of a commercial probe assay for detection of rifampin resistance in Mycobacterium tuberculosis directly from respiratory and nonrespiratory clinical samples.

A commercial assay (Inno-Line Probe Assay; Innogenetics, Belgium) was evaluated to determine its ability to detect rifampin resistance in Mycobacterium tuberculosis directly from clinical specimens. Fifty-nine selected specimens (42 respiratory and 17 nonrespiratory) culture positive for Mycobacterium tuberculosis were tested along with their corresponding isolates in culture. The results were compared with those obtained by in vitro susceptibility testing. The results of the line probe assay to detect rifampin resistance in Mycobacterium tuberculosis present in clinical specimens and in cultured isolates were concordant for 58 of 59 (98.3%) isolates (95% confidence limits = 90.9-99.9%). The line probe assay failed only once, when a fecal specimen was tested; no amplification was observed due to the presence of inhibitory compounds. The most frequently observed mutation was His526-->Asp (58.7%), followed by the His526-->Tyr (23.9%); together, they represented 82.6% of rifampin-resistant samples. In conclusion, the Inno-Line Probe Assay is a rapid, useful method for detecting the presence of Mycobacterium tuberculosis complex and its resistance to rifampin directly from clinical specimens and culture. Moreover, since rifampin resistance is a potential marker for multidrug resistance in Mycobacterium tuberculosis, this assay may constitute an important tool for the control of tuberculosis.

Antibiotics, Antitubercular↗
PubMed1998

Comparison of a nonradiometric system with Bactec 12B and culture on egg-based media for recovery of mycobacteria from clinical specimens.

The MB/BacT (Organon-Teknika, USA) is a fully automated, rapid, nonradiometric system for the culture of mycobacteria from clinical samples. The rate of recovery of mycobacteria and the time to detection obtained with the MB/ BacT were compared with those obtained with Löwenstein-Jensen and Coletsos solid media and Bactec 7H12 (12B) (Becton-Dickinson, USA) broth when 600 processed specimens were inoculated into all media in parallel. Specimens included 383 respiratory samples, 20 urine samples, 23 purulent exudates, 13 stool samples, 103 blood samples, 14 bone marrow aspirates, and 44 body fluid samples or aspirates. Overall, 106 mycobacterial isolates comprising six species were recovered, of which 100 (94.3%) were detected with MB/BacT, 98 (92.5%) with egg-based media, and 96 (90.2%) with Bactec 12B. The recovery rates of Mycobacterium tuberculosis complex with MB/BacT, egg-based media, and Bactec 12B were 98.7%, 93.7, and 89.9%, respectively. The average number of days to detection of single mycobacterial isolates was 14.2 days for MB/BacT, 26.1 days for egg-based media, and 11.7 days for Bactec 12B. The contamination rates were higher in MB/BacT (5%) than in Bactec 12B (1.8%) or egg-based media (1.5%). MB/BacT is a reliable, nonradiometric, less labor-intensive alternative to Bactec 12B for recovery of mycobacteria, but, as with other liquid culture methods, MB/BacT should be used in combination with a solid medium, not on its own.

Bacteriological Techniques↗
PubMed1998

Evaluation of Meridian ImmunoCard Mycoplasma test for the detection of Mycoplasma pneumoniae-specific IgM in paediatric patients.

The Meridian ImmunoCard Mycoplasma kit, a 10-min card-based enzyme-linked immunosorbent assay (ELISA) designed to detect immunoglobulin M (IgM) antibodies to Mycoplasma pneumoniae was evaluated. We compared the ImmunoCard with the Fujirebio Serodia Myco II particle agglutination test, as well as with the complement fixation (CF) test to detect M. pneumoniae antibodies in paediatric patients. The ImmunoCard test and Serodia Myco II test agreed in 93.95%, and ImmunoCard test and CF test agreed in 83.51% of the 182 specimens tested. Nine specimens gave negative particle agglutination titres in the acute phase sample, and 28 specimens gave negative CF titres in the acute phase sample, although in the ImmunoCard test they were positive. These results may indicate that the ImmunoCard assay detects lower IgM levels of antibodies than the Serodia Myco II and CF test. The ImmunoCard appears to be a good screening assay test for M. pneumoniae IgM in children in whom M. pneumoniae IgM is found frequently.

Acute-Phase Reaction↗
PubMed1998

Role of immunosuppression in the evolution of Legionnaires' disease.

The clinical course of legionella pneumonia in immunosuppressed patients is uncertain. This study was undertaken to determine the clinical evolution of legionellosis on the basis of the immune state and to establish the variables associated with death directly related to legionellosis. The study included 78 patients: 28 with chronic disease who had received immunosuppressive treatment (group 1), 24 with chronic disease without immunosuppressive treatment (group 2), and 26 controls. Inclusion criteria were the occurrence of nosocomially acquired pneumonia, Legionella pneumophila infection, and erythromycin therapy that was initiated within 72 hours following diagnosis. Respiratory and extrarespiratory complications were observed more frequently in groups 1 and 2. Bilateral radiological involvement was most frequent in group 1, and recurrence of legionella pneumonia was observed exclusively in group 1. None of these variables achieved statistical significance. The global mortality of the series was 11.5% (17.9%, 12.5%, and 3.8% in groups 1, 2, and 3, respectively). Variables statistically related to mortality were acute renal failure, shock, and need for mechanical ventilation. Although many of the variables analyzed lacked statistical significance, a trend was seen between complications and basal immunosuppression, as previously suggested.

Aged↗
PubMed1998

Comparative evaluation of initial and new versions of the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test for direct detection of Mycobacterium tuberculosis in respiratory and nonrespiratory specimens.

We evaluated the initial version of the Amplified Mycobacterium Tuberculosis Direct Test (Gen-Probe) (AMTDT 1) and the new version of AMTDT (AMTDT 2) for the detection of Mycobacterium tuberculosis directly from respiratory and nonrespiratory samples and compared the results with those of culture and staining methods. The assays were applied to 410 respiratory and 272 nonrespiratory samples collected from 515 patients. The combination of the culture results and clinical diagnosis was considered to be the "gold standard." Ninety-five respiratory specimens were collected from 67 patients with a diagnosis of pulmonary tuberculosis (TB) and 68 nonrespiratory specimens were collected from 61 patients with a diagnosis of extrapulmonary TB. With respiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 96%, respectively, for AMTDT 1 and 94.7, 100, 100, and 98.4%, respectively, for AMTDT 2. With nonrespiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 94%, respectively, for AMTDT 1 and 86.8, 100, 100, and 98.4%, respectively, for AMTDT 2. The overall results of AMTDT 1 and AMTDT 2 were concordant for 97% (661 of 682) of the samples. Statistically significant differences in sensitivities were found between AMTDT 1 and AMTDT 2 with respiratory specimens. It was concluded that although both nucleic acid amplification methods are rapid, sensitive, and specific for the detection of M. tuberculosis complex in all types of clinical samples, AMTDT 2 appeared to be more sensitive than AMTDT 1 when applied to smear-negative specimens. In contrast AMTDT 2 is more susceptible than AMTDT 1 to inhibitory substances in the amplification reaction. The turnaround time of AMTDT 2 is shorter (3.5 h) than that for AMTDT 1 (5 h).

Bacteriological Techniques↗
PubMed1998

Rapid diagnosis of extrapulmonary tuberculosis by ligase chain reaction amplification.

A rapid amplification-based test for the diagnosis of extrapulmonary tuberculosis, the LCx Mycobacterium tuberculosis Assay from Abbott Laboratories, was evaluated. Results from the LCx M. tuberculosis Assay were compared with those from culture and the final clinical diagnosis for each patient. A total of 526 nonrespiratory specimens from 492 patients were tested. The specimens included urine; feces; lymph node exudates; pleural, cerebrospinal, articular, and ascitic fluids; tissue biopsies; gastric aspirates; purulent exudates; blood; and bone marrow aspirates. After combination of the culture results and the patient's clinical data, a total of 135 specimens were collected from 122 patients with a diagnosis of extrapulmonary tuberculosis. The sensitivity, specificity, and positive and negative predictive values for the LCx M. tuberculosis Assay were 77.7, 98.7, 95.2, and 93.1%, respectively; these values rose in resolved cases of TB to 78.5, 100, 100, and 93.1%, respectively. For 37 (27.4%) specimens from patients smear positive for the disease and 98 (72.6%) specimens from patients smear negative for the disease, the sensitivities of the LCx M. tuberculosis Assay were 100 and 71.1%, respectively. Statistically significant differences (P < 0.01) in sensitivities were found between culture and the LCx M. tuberculosis Assay. These differences were even greater among smear-negative specimens. The results demonstrate that the LCx M. tuberculosis Assay will provide rapid and valuable information for the diagnosis of extrapulmonary tuberculosis.

Humans↗
PubMed1998

Comparison of the Binax Legionella urinary antigen enzyme immunoassay (EIA) with the Biotest Legionella Urin antigen EIA for detection of Legionella antigen in both concentrated and nonconcentrated urine samples.

We evaluated a newly commercial enzyme immunoassay (EIA) (Biotest Legionella Urin Antigen EIA; Biotest AG, Dreieich, Germany) for detection of antigens of all Legionella pneumophila serogroups with a relatively wide spectrum of cross-reactivity as well as antigens of other Legionella spp. by comparing its sensitivity and specificity with those of an EIA for detection of L. pneumophila serogroup 1 antigen (Legionella urinary antigen EIA; Binax, Portland, Maine). Both tests were performed with both concentrated and nonconcentrated urine samples. We also evaluated the capabilities of both EIAs to detect extracted soluble antigens of American Type Culture Collection (ATCC) Legionella strains (L. pneumophila serogroups 1 to 14, L. bozemanii, and L. longbeachae). The sensitivity of the Biotest EIA was 66.66% in nonconcentrated urine and 86.66% in concentrated urine. The sensitivity of the Binax EIA was 63.76% and 88.88% in nonconcentrated and concentrated urine, respectively. The specificity was 100% in nonconcentrated and concentrated urine for both assays. The Binax EIA and Biotest EIA detected extracted soluble antigens of L. pneumophila serogroups 1 to 14 and L. bozemanii ATCC strains. The cross-reactions observed with the Binax EIA were probably due to common epitopes directly related to lipopolysaccharide. Further studies are required to determine the usefulness of the Binax EIA for detection of urinary antigens from Legionella species and serogroups other than L. pneumophila serogroup 1. The Biotest EIA proved to be as rapid, sensitive, and specific as the Binax EIA for the diagnosis of legionellosis. Concentration of antigen present in urine increased the sensitivities of both techniques with no reduction in specificity.

Adult↗
PubMed1997

Inactivation of hepatitis B virus: evaluation of the efficacy of the disinfectant 'Solprogel' using a DNA-polymerase activity assay.

The effects of sodium dichloroisocyanurate (NaDCC) and Solprogel (Laboratorios Inibsa, S.A., Barcelona, Spain), a compound that contains NaDCC plus a biodegradable polymer of acrylic acid, on the activity of DNA polymerase (DNA-P) associated with hepatitis B virus in serum were evaluated. DNA-P positive and negative pools of human serum samples were used as positive and negative stock virus. Inhibition of DNA-P activity by NaDCC and the commercial product was found to be concentration-dependent. Two minutes exposure to the minimum effective concentration of NaDCC (1000 ppm available chlorine) or Solprogel 16% (960 ppm available chlorine) totally inhibited DNA-P activity.

Antiviral Agents↗
PubMed1997

Direct detection of Mycobacterium tuberculosis complex in nonrespiratory specimens by Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test.

The Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (AMTDT) was adapted for the detection of Mycobacterium tuberculosis complex in 224 nonrespiratory specimens from 188 patients. The sensitivity and specificity of the AMTDT for such specimens, after resolution of discrepant results, were 85.7 and 100%, respectively. Pretreatment of nonrespiratory specimens with sodium dodecyl (lauryl) sulfate is mandatory to obtain consistent and reproducible AMTDT results. The use of 500 microliters of decontaminated specimen improves the sensitivity of the test. Because the AMTDT detects stable rRNA from noncultivable bacilli, it is not useful for monitoring patients receiving treatment.

Bacterial Typing Techniques↗
PubMed1997

Detection of lipoarabinomannan antibodies in patients with newly acquired tuberculosis and patients with relapse tuberculosis.

A commercially available dot immunoassay that employs the lipoarabinomannan antigen was evaluated for the serologic diagnosis of tuberculosis. The test showed a high specificity (100%); however, its sensitivity was low (18.5%). Antibodies to lipoarabinomannan were detected in the sera of 7 of 71 patients with newly acquired tuberculosis and in sera of 10 of 21 patients with relapse tuberculosis. It has been shown by others that sera from patients with relapse tuberculosis had a higher concentration of antibodies and reacted with a greater variety of antigens (native culture filtrates of Mycobacterium tuberculosis H37Rv) than did sera from patients with newly acquired tuberculosis. Our data confirm the results of these previous studies as far as lipoarabinomannan is concerned. We conclude that the differences in the production of antibodies shown by the two groups of tuberculous patients (new and relapse) must be taken into account when assessing the usefulness of serologic tests for the diagnosis of tuberculosis.

Antibodies, Bacterial↗
PubMed1997

Comparison of radioimmunoassay and enzyme immunoassay kits for detection of Legionella pneumophila serogroup 1 antigen in both concentrated and nonconcentrated urine samples.

We evaluated a commercial enzyme immunoassay (EIA) kit for detection of Legionella pneumophila serogroup 1 soluble antigen by comparing it to radioimmunoassay (RIA), using both concentrated and nonconcentrated urine samples. The sensitivity of EIA was 67.4% in nonconcentrated urine samples and 82.6% in concentrated urine samples. The sensitivity of RIA was 60.9% and 84.8% in nonconcentrated and concentrated urine samples, respectively. Our study indicates that the sensitivity and specificity of EIA are comparable to those of RIA, and that concentrating the antigen by selective ultrafiltration increases sensitivity for both EIA and RIA, with no significant decrease in specificity.

Adult↗
PubMed1997

Evaluation of the semiautomated Abbott LCx Mycobacterium tuberculosis assay for direct detection of Mycobacterium tuberculosis in respiratory specimens.

Five hundred twenty processed respiratory specimens from 326 patients received for the diagnosis of tuberculosis or other mycobacterial infections were tested by means of the LCx Mycobacterium tuberculosis Assay from Abbott Laboratories, which uses ligase chain reaction technology for the direct detection of M. tuberculosis complex in respiratory specimens. The results of the LCx M. tuberculosis Assay were compared with the results of culture and staining techniques. After a combination of culture results and the patient's clinical data, a total of 195 specimens were collected from 110 patients who were positively diagnosed as having pulmonary tuberculosis. Twenty-three of these 195 specimens which corresponded to 10 patients with a history of pulmonary tuberculosis (TB) and anti-TB treatment ranging from 1 to 6 months were culture negative. The other 172 specimens were culture positive for M. tuberculosis. With an overall positivity rate of 37.5% (195 of 520 specimens), the sensitivity, specificity, and positive and negative predictive values were 90.8, 100, 100, and 94.7%, respectively, for the LCx M. tuberculosis Assay; 88.2, 100, 100, and 93.4%, respectively, for culture; and 82.6, 92, 72.9, and 97.6%, respectively, for acid-fast staining. For 161 specimens (82.6%) from patients smear positive for the disease and 34 specimens (17.4%) from patients smear negative for the disease, the sensitivity values for the LCx M. tuberculosis Assay were 98.8 and 53%, respectively. There were no statistically significant differences in the sensitivities and specificities between the LCx M. tuberculosis Assay and culture (P > 0.05). Conclusively, the LCx M. tuberculosis Assay has proved to have an acceptable sensitivity and a high specificity in detecting M. tuberculosis and has the potential of reducing the diagnosis time to an 8-h working day.

Bacterial Typing Techniques↗
PubMed1997

Detection and identification of mycobacteria by amplification of RNA and DNA in pretreated blood and bone marrow aspirates by a simple lysis method.

A sodium dodecyl (lauryl) sulfate method was evaluated for the preparation of blood specimens and bone marrow aspirates for use in two amplification procedures (Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test [AMTDT] and Roche Amplicor M. avium/M. intracellulare [MAI] Test) for the detection and identification of Mycobacterium tuberculosis and M. avium and M. intracellulare, respectively. The AMTDT is based on amplification of rRNA, whereas the Amplicor MAI Test amplifies a specific DNA region of the 16S rRNA gene. The results of amplification techniques were compared with those of standard culture and culture in BACTEC 13A and BACTEC 12B liquid media. A total of 121 blood specimens and 15 bone marrow aspirates were collected from 136 AIDS patients. Mycobacterial growth was recovered for 103 specimens; 35 yielded M. tuberculosis, 62 yielded M. avium, 5 yielded M. genavense, and 1 yielded M. kansasii. The values of sensitivity and specificity in pretreated specimens for detection of M. tuberculosis by the AMTDT were 94.3 and 100%, respectively, and those for detection of M. avium by the Amplicor MAI Test were 91.9 and 100%, respectively. The simple lysis method described in the present work allows the recovery of mycobacteria from blood specimens and bone marrow aspirates and may be used in combination with the AMTDT and the Amplicor MAI Test to detect and identify different members of the genus Mycobacterium. This method might also be applicable for the identification of mycobacteria from blood culture fluids with acridinium-ester-labeled DNA probes.

AIDS-Related Opportunistic Infections↗
PubMed1997

Rapid detection of Mycobacterium tuberculosis in respiratory specimens, blood and other non-respiratory specimens by amplification of rRNA.

SETTING: Diagnostic methods employing gene technology based on amplification of DNA or RNA are expected to improve the speed, sensitivity, and specificity of Mycobacterium tuberculosis detection. The Amplified Mycobacterium Tuberculosis Direct Test (AMTDT) enables the amplification and detection of M. tuberculosis rRNA directly from respiratory specimens. OBJECTIVE: To evaluate the performance of the AMTDT in direct detection of M. tuberculosis in respiratory specimens, blood and other clinical samples, and to compare this method with conventional culture and staining techniques. DESIGN: A total of 554 samples from 450 patients were examined in this study. All clinical specimens (with the exception of bone marrow aspirates and blood samples) were digested and decontaminated with sodium dodecyl (lauryl) sulfate (SDS)-NaOH. Bone marrow aspirates and blood samples were treated with 10% SDS. All processed samples were stained by auramine-rhodamine fluorochrome and inoculated onto Löwenstein-Jensen and Coletsos solid media, and into BACTEC-12B medium. In addition, the blood samples were inoculated into BACTEC 13A medium. The AMTDT was performed according to manufacturer's instructions. In those cases where discrepant results were obtained for AMTDT and cultures, patients' clinical data and other microbiological results were evaluated. RESULTS: The sensitivity, specificity, and positive and negative predictive values for AMTDT were 87.5, 100, 100, and 96.7%, respectively, in respiratory specimens and 86.8, 100, 100, and 92.8%, respectively, in non-respiratory specimens. The differences in sensitivity of these two groups of specimens were not highly statistically significant (P > 0.005). CONCLUSION: The sensitivity and specificity of the AMTDT were satisfactory for detection of M. tuberculosis in all types of clinical samples. Some minor changes in assay format and laboratory protocols may increase the sensitivity of the AMTDT without adversely affecting its specificity.

Bacteriological Techniques↗
PubMed1996

Impact of using an indwelling introducer on diagnosis of Swan-Ganz pulmonary artery catheter colonization.

A prospective study was conducted to determine how the use of an indwelling introducer influences the diagnosis of pulmonary artery catheter (PAC) colonization. Sixty-six consecutive PACs and introducers were aseptically removed over a 15-month period. Two segments of the catheter and the catheter tip (a proximal segment from the portion of the catheter beneath the introducer) and two segments of the introducer (a proximal intradermal segment and the introducer tip) were cultured using a semiquantitative technique. Nineteen of 66 (28.7%) PACs showed colonization, representing an incidence of 5.6 episodes per 100 catheterization-days. Catheter tip cultures identified only 68% of colonized PACs; this yield rose to 91% when introducer tip cultures were added. These results indicate a need to evaluate both introducer tip cultures and catheter tip cultures for an accurate diagnosis of PAC colonization when an indwelling introducer is used.

Bacteria↗