Study of respiratory viruses and the co-infection with bacterial and fungal pathogens in acute exacerbation of chronic obstructive pulmonary diseases

Background: The study on infectious etiology of AECOPD is largely restricted to only viral or only bacterial etiology. This prospective study was conducted over 2 years to estimate the overall incidence rate and profile of viral infections in AECOPD patients, co-infection of the viral agents with other bacterial and fungal agents, association of the type and pattern of infective agent with the clinical severity. Methods and materials: From all patients, nasopharyngeal (NP) swab, sputum, and blood were collected. qRT-Multiplex PCR was performed from the nasopharyngeal swab using FTD respiratory pathogens 21 plus kit. ZN stain, modified MZN, KOH mount were performed for mycobacteria, nocardia and fungal elements. Bacterial cultures, fungal cultures were done as per standard techniques. Serum samples were tested for Mycoplasma and Chlamydia pneumonia Ig M ELISA and semiquantitative CRP. Results: 74 AECOPD cases were included in the study. The AECOPD events which had only viral infection, only bacterial infection, bacterial–viral co-infection, fungal infection and no infection were 23 (31%), 12 (16%), 20 (27%), 3 (4%) and 16 (22%) respectively. Most common virus identified was Influenza A (22/43; 51%). The number of cases having monoviral (MV) and polyviral (PV) infections were 26 and 17 respectively. In PV infection most common pattern being IAV + IBV, followed by HRV + PIV3. Most common bacteria isolated were Pseudomonas aeruginosa (9/32, 28%). Sputum sample of 3 patients (3/74; 4%) were positive for Aspergillus flavus. 49 samples (66%) had elevated CRP. Elevated CRP level was significantly associated with presence of any infective agents, bacterial infection and with co-infection (p < 0.001), (p < 0.001), (p = 0.002), respectively. Conclusion: This information on the epidemiology of respiratory infections in AECOPD will improve the management of AECOPD using timely institution of antivirals and reduce the overuse of antibiotics and the implementation of routine influenza vaccination.