Laboratory Investigation of Trends in Bacterial Pneumonia in Cheonan, Korea, from January 2008 to September 2017

Bacterial pneumonia is one of the most common causes of mortality in Korea. In 2016, the mortality rate from pneumonia was 16,476 deaths per 100,000, which was an 11% increase from the previous year. The aim of our study was to determine the distribution of the bacterial pathogens causing respiratory symptoms in different age groups over a 10-year period. Between January 2008 and September 2017, 1,861 specimens from 1,664 patients admitted to Dankook University Hospital with respiratory symptoms were examined. We used multiplex polymerase chain reaction (PCR) to detect six bacterial pneumonia pathogens: Bordetella pertussis, Chlamydophila pneumoniae, Haemophilus influenzae, Legionella pneumophila, Mycoplasma pneumoniae, and Streptococcus pneumoniae. We detected bacterial pneumonia pathogens in 1,281 (68.83%) specimens. Of the 1,709 pathogens detected, S. pneumoniae was the most common (48.57%; n = 830) followed by H. influenzae (40.08%; n = 685). Most infections were found among children younger than 10 years (92.69%; n = 1,584). Although S. pneumoniae was the most common pathogen detected in all age groups, M. pneumoniae infection increased in prevalence with age (p < 0.05). The rate of co-infection was also high among these patients (31.1%; n = 399), which peaked in 2015 (54.55%; n = 42/77). The prevalence of bacterial pneumonia in Cheonan, along with the proportion of co-infections among patients increased over the 10-year study period. The findings will aid the development of treatment and prevention guidelines.