Direct Detection of Atypical Bacteria in Clinical Samples from Patients with Chronic Obstructive Pulmonary Disease (COPD) by PCR and RT-PCR

Chronic obstructive pulmonary disease (COPD) represents an important public health challenge and is a major cause of morbidity and mortality throughout the world. The chronic course of COPD is often accompanied by acute exacerbations of COPD (AECOPD) where 70% of exacerbations are caused by infection due to aerobic bacteria, 30% due to viruses and 5-10 % by atypical bacteria, most commonly Mycoplasma pneumoniae (M. pneumoniae), Chlamydia pneumoniae (C. pneumoniae) and Legionella pneumophila (L. pneumophila). Identification of these atypical microorganism is challenging, however, with the availability of newer molecular diagnostic techniques such as PCR and Real time PCR (RT-PCR) the sensitivity in detecting these pathogens has improved and can be tested simultaneously. So, the present prospective study was undertaken to determine the atypical pathogens in patients with COPD by PCR and RT-PCR in the clinical samples. 196 hospitalized patients were included in the study. They were categorized into different stages of COPD and AECOPD using GOLD and Anthonisen criteria. Clinical samples such as throat swab, nasopharyngeal swab, sputum, were collected. Atypical bacteria were identified by using PCR and RT-PCR methods. All these patients showed varying degree of exacerbation. Majority, 78/196 (39.79%) of the patients belonged to severe COPD category. Whereas, 96/193(49.74%) patients had only mild exacerbation. PCR was found to be positive in 11 and 22 numbers for M. pneumoniae and L.pneumophila. None of the samples were positive for Chlamydia pneumophila. Presence of pathogens, atypical bacteria did not show any correlation with the staging of AECOPD. The results were not statistically significant. No one method is suitable for the detection of atypical bacteria. Hence, a combination of tests for identification of Atypical pathogens is required for better sensitivity.