Objective. This study is aimed at investigating the pattern of change occurring in respiratory pathogens before and after the outbreak of COVID‐19, a type of viral pneumonia for which a pandemic was declared (March 2020). The results were analyzed by gender and age to identify the association between personal hygiene and prevention of infection by respiratory pathogens. Methods. A retrospective analysis was performed on 39,814 sputum, bronchial aspirate, and transtracheal aspirate samples obtained from 15,398 patients visiting a university hospital, located in Chungcheongnam‐do, South Korea, between January 2018 and December 2021. From 4,454 patients whose samples were culture positive for bacteria, 6,389 strains were isolated and further cultured. Results. The mean age of the outpatients with respiratory pathogens was 66.2 years, and the comparison of the culture test results by gender showed that 64.9% (2,892/4,454) were male and 35.1% (1,562/4,454) were female. Compared to the pre‐COVID‐19 pandemic period, the number of outpatients with a request for respiratory microbial cultures after the onset of the pandemic was reduced by 20.7% and the number of outpatients with a positive culture result was reduced by 23.0%. The number of respiratory samples received was reduced by 6.7% after the pandemic, while the sample positive rate was reduced by 18.3%. Among the isolated microbial strains, there was a significant decrease of 43.1% for the Acinetobacter baumannii complex, 60.5% for Streptococcus pneumoniae, 67.2% for Haemophilus influenzae, and 78.1% for Moraxella catarrhalis when compared with pre‐COVID‐19 levels. The distribution of respiratory microbial strains by age group showed that the highest percentage of isolated strains was in patients in their 70s. Conclusions. The improvements in personal hygiene due to the COVID‐19 pandemic exerted a substantial influence on the pattern of change in other common respiratory microorganisms, which highlights the importance of personal hygiene management in the prevention of respiratory infections.

In this study, we aimed to analyze the annual, age- and sex-specific frequencies and antifungal resistance rates of Candida albicans infections over an 11-year period (2013 - 2023) at a university hospital in South Chungcheong Province, South Korea. A total of 476 cases identified as C. albicans from 260,769 blood cultures were analyzed retrospectively. The annual number of C. albicans isolates increased by 161.1% in 2019 and 136.7% in 2022 compared with that in the previous year. The mean age of patients from whom C. albicans was isolated was 65.8 years, with 51.8% patients being aged 60-79 years. The number of isolates was higher in male patients than in female patients (male-to-female ratio: 1.4:1). Of the isolates, 6.6% were resistant to flucytosine and 4.5% were resistant to voriconazole, whereas all isolates were susceptible to caspofungin and micafungin. Overall, this study provides vital foundational data for tertiary general hospitals in the Chungcheong region and for developing national infection management strategies, thereby providing a valuable basis for future in-depth studies.

Although tuberculosis burden is generally declining, the relative importance of nontuberculous mycobacteria (NTM) is increasing. In South Korea, few studies have evaluated Mycobacterium tuberculosis complex (MTBC) and NTM detection patterns and species distribution using long-term data. We retrospectively compared MTBC and NTM detection patterns using respiratory specimen-based laboratory data from a tertiary care hospital in South Korea (2016–2025). We analyzed 48,533 specimens, and the sum of annual patient counts after within-year deduplication was 30,275. Patient-level positivity decreased for MTBC (4.7% to 2.4%) but increased for NTM (7.7% to 10.3%), with corresponding changes at the specimen level. Age- and sex-adjusted annual odds ratios (95% confidence intervals) were 0.913 (0.892–0.934) for MTBC and 1.009 (0.994–1.023) for NTM; the overall linear NTM trend was nonsignificant. NTM-positive patients were older than MTBC-positive patients (median, 73 vs. 64 years). Co-detection of MTBC–NTM or multiple NTM species or subspecies was also observed. MTBC positivity declined, whereas NTM positivity increased mainly during 2016–2019; the relative proportion of NTM detections increased. Co-detection in the same specimen suggests the importance of differentiating MTBC from NTM and identifying NTM. Our findings may inform the development of institutional laboratory diagnostic strategies.