Study of respiratory viruses and their coinfection with bacterial and fungal pathogens in acute exacerbation of chronic obstructive pulmonary diseases

Background: Patients with chronic obstructive pulmonary disease (COPD) develop acute exacerbations (AE), with varying natural history. The exacerbation is triggered by infection, leading to increased morbidity and mortality. The study on infectious aetiology of AECOPD is largely restricted to only viral or only bacterial aetiology. There are no studies from India that have investigated multiple viral, bacterial, and fungal associations from the same group of patients. This prospective study was conducted over 2 years to estimate the incidence and profile of viral infections in AECOPD patients, their coinfection with other bacterial and fungal agents, and association of the type and pattern of infective agent with the clinical severity. Materials and Methods: Seventy-four AECOPD cases were included in the study. Multiplex polymerase chain reaction was performed from nasopharyngeal swab using Fast Track Diagnostics Respiratory Pathogens 21 Plus Kit. Ziehl–Neelsen (ZN) stain, Modified ZN, and potassium hydroxide (KOH) mount were performed for Mycobacteria, Nocardia, and fungal elements. Bacterial cultures and fungal cultures were done as per the standard techniques. Serum samples were tested for Mycoplasma and Chlamydia pneumoniae immunoglobulin M enzyme-linked immunosorbent assay. Results: The number of AECOPD events involving only viral infection, only bacterial infection, bacterial–viral coinfection, and no infection were 43 (58.1%), 32 (43.2%), 20 (27%), and 19 (25.7%), respectively. Influenza A virus was the most common virus (22/43, 51%) identified. In 26 patients, monoviral infections were found, and in 17 patients, polyviral infections were identified, the most common pattern being influenza A and B virus, followed by human rhinovirus and human parainfluenza. The most common bacteria isolated were Pseudomonas aeruginosa (9/32,28%) followed by Acinetobacter baumanii and Klebsiella pneumoniae (7/32, 21%). Among the viral–bacterial coinfection, human coronavirus NL63 infection was always associated with a bacterial infection. Conclusion: This information on the various viral and bacterial etiologies of respiratory infections in AECOPD in this part of India will improve the understanding of the management of AECOPD using a timely institution of antivirals and reduce the overuse of antibiotics and the implementation of routine influenza vaccination.