Viral and bacterial etiologies in acute exacerbation of COPD detected using a multiplex real-time polymerase chain reaction

Background: Acute exacerbation is a major concern affecting the mortality and morbidity rates associated with COPD. The most common causes of acute exacerbation of COPD (AE_COPD) are respiratory infection by rhinovirus (RV), influenza virus (FLU), Haemophilus influenzae ( H.flu ), and Streptococcus pneumoniae ( S.pn ). The causative organisms of AE_COPD identified using a multiplex polymerase chain reaction (MRT-PCR) have rarely been documented. Aims: To evaluate the etiologies in AE_COPD, a rapid reliable process based on MRT-PCR for respiratory samples was used. Methods: From Sep. 2012 to Jan. 2014, we prospectively enrolled AE_COPD patients who satisfied our criteria: an age of 20 years or older, within 7 days of onset, and the informed consent. Nasopharyngeal swabs (NPS) and sputum samples were collected from all the patients, and a MRT-PCR was used to detect 6 types of bacteria and 11 types of respiratory viruses. Bacterial cultures of both specimens were performed. Results: Both bacteria and/or viruses were detected using MRT-PCR in 24 (66.6%) of the 36 patients who satisfied our enrollment criteria. Using acombination of MRT-PCR and culture, the pathogens associated with AE_COPD were identified in 30 (83.3%) of the cases. The most commonmicroorganisms were H.flu , S.pn , RV, and FLU. An elevated CRP level and infection with a microorganism other than H.flu were significantly associated with a need for long-term hospitalization. Conclusions: Our results suggest the usefulness of MRT-PCR for the analysis of NPS and sputum samples to determine the etiology of AE_COPD. Based on the results, we analyzed the association between microorganisms and AE_COPD.