The most common isolates from pleural infections.

Isolation and identification of the pathogens are important for appropriate treatment of pleural infections. Distribution of the most frequent causative agents varies throughout the world and may change in time.The objective of the study is to analyze the bacteriological isolates of pleural fluids in order to identify the most frequent infectious agents and assess their variability in time.The retrospective study included 272 patients with positive pleural fluid samples analyzed in 5-year period. The samples were examined using the conventional microbiological technique.Of 315 bacterial isolates the most common were streptococcal species, 105 (33%), of which 55 (17.3%) represented the Streptococcus milleri group. Gram-positive anaerobic cocci were detected in 56 (17.6%) isolates. Enterobacteriaceae family included 27 (8.5%) isolates and Pseudomonas aeruginosa was registered in 13 (4.1%). No statistically significant difference was registered in pathogen distribution in the examined period (p = 0.288).The most common agents of community-acquired pleural infections are the Streptococcus milleri group and anaerobic Gram-positive cocci. They differ from the most common pathogens of pneumonia. Among the hospital-acquired pleural infections, Pseudomonas species, Staphylococcus aureus and enterobacteria prevail. The distribution of bacterial agents isolated in the 5-year period exhibits no significant differences.

Use of immunochromatographic assay for rapid identification of Mycobacterium tuberculosis complex from liquid culture.

A new, simple immunochromatographic assay for rapid identification of Mycobacterium tuberculosis complex in liquid cultures has been developed. The principle of the assay is binding of the Mycobacterium tuberculosis complex specific antigen to the monoclonal antibody conjugated on the test strip. The aim of this study is evaluation of the performance of immunochromatographic assay in identification of Mycobacterium tuberculosis complex in primary positive liquid cultures of BacT/Alert automated system. A total of 159 primary positive liquid cultures were tested using the immunochromatographic assay (BD MGIT TBc ID) and the conventional subculture, followed by identification using biochemical tests.Of 159 positive liquid cultures, using the conventional method, Mycobacterium tuberculosis was identified in 119 (74.8%), nontuberculous mycobacteria were found in 4 (2.5%), 14 (8.8%) cultures were contaminated and 22 (13.8%) cultures were found to be negative. Using the immunochromatographic assay, Mycobacterium tuberculosis complex was detected in 118 (74.2%) liquid cultures, and 41 (25.8%) tests were negative. Sensitivity, specificity, positive and negative predictive values of the test were 98.3%; 97.5%; 99.15% i 95.12%, respectively. The value of kappa test was 0.950, and McNemar test was 1.00. The immunochromatographic assay is a simple and rapid test which represents a suitable alternative to the conventional subculture method for the primary identification of Mycobacterium tuberculosis complex in liquid cultures of BacT/Alert automated system.

[Microbiological diagnosis of tuberculosis in Serbia in the period 2001-2003].

INTRODUCTION: The National tuberculosis Reference Laboratory (NTRL) and the National TB Laboratory Network in Serbia, provided data on drug susceptibility profiles of M. tuberculosis, incidence of TB among laboratory workers and on protective measures. MATERIAL AND METHODS: The TB laboratory network in Serbia comprises 46 laboratories. 11 laboratories perform acid fast microscopy only, 24 perform microscopic and culture examinations, and complete identification and drug susceptibility testing (DST) is performed in 11 laboratories. Protective measures for laboratory workers are mostly inadequate. Four cases of occupational TB were reported over the study period. RESULTS: DST was performed in 61.8% to 62.8% of bacteriologically proven TB cases. Isolates of M. tuberculosis strains showing drug-resistance ranged from 7.9% to 8.9%, while multidrug resistant (MDR) isolates varied from 2.2% to 2.5%. In order to determine the accuracy of DST in 6 local laboratories, NTRL carried out a quality assurance program for DST. Four laboratories reached 100% agreement with NTRL for rifampicin. At least 90% agreement with NTRL for isoniazid was achieved in three tested laboratories. CONCLUSION: A relatively low and stable rates of drug-resistant and MDR TB in our study indicate that the situation in Serbia is still satisfactory. However, a reliable surveillance of drug-resistant TB in the region requires routine DST of all patients with culture confirmed TB. This is one of the goals included in the new National TB Program. In summary, all laboratories in Serbia should be included in the quality assurance program and their number should be reduced in accordance with the annual number of analyses performed, geographical location and results of proficiency testing.