Atypical bacteria, including Mycoplasma pneumoniae, Chlamydophila pneumonia and Legionella pneumophila play significant role in respiratory tract infections and account for 40% of all cases of community acquired pneumonia (CAP). These organisms also commonly occur as co-pathogens in mixed infections with mortality rates as high as 25%. The biological mechanisms and diagnosis of atypical infections is presented in this study.

BACKGROUND:A study was undertaken to evaluate the usefulness of telomerase activity assay in transthoracic fine needle biopsy (TFNB) aspirates collected from peripheral tumours of the lung in predicting the malignant aetiology of lung infiltrations.METHODS:100 patients with a peripheral infiltration of the lung underwent TFNB of the focal lesion. The aspirates were subjected to standard cytological evaluation. Telomerase activity in the specimens was determined with the PCR-ELISA PLUS method. The sensitivity, specificity, accuracy and predictive value of TFNB were calculated for cytological examination of aspirates alone and cytological examination with additional telomerase activity assessment.RESULTS:Lung cancer was newly diagnosed in 84 subjects and benign peripheral lesions were found in 16. During the first TFNB, lung cancer was identified in 56 cases of cancer (66.7%) while increased telomerase activity was found in 61 cancer aspirates (72.6%). No subject with a benign infiltration had a false positive result from cytological examination, but in one case (6.25%) increased telomerase activity was observed. The diagnostic sensitivity, accuracy and negative predictive value of the combination of cytological examination and telomerase activity assay in TFNB specimens were significantly higher than for cytological examination alone (89.3% vs 66.7%, p = 0.0004; 90% vs 72%, p = 0.001; 62.5% vs 36.4%, p = 0.039), but a combination of the two examinations was associated with a lower specificity of TFNB (96.9% vs 100%, p = 0.002).CONCLUSION:Detection of telomerase activity in aspirates taken during TFNB of a peripheral lung infiltration should be considered as an indication of the risk of malignancy in cases with false negative cytological results.