Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology
Young Ah Kim, Jaekwang Lee, Sunmin Lee
Ann Clin Microbiol 2025 September, 28(3):12. Published on 24 July 2025.
Backgrounds: The coronavirus disease 2019 (COVID-19) pandemic has retreated the years of progress that essential tuberculosis (TB) medical services provided in reducing the burden of TB. This study evaluated the clinical impact of the COVID-19 pandemic on TB management based on treatment discontinuation and mortality rates.
Methods: Two time intervals were included in this study: before the spread of COVID-19 (2018–2019) and during the pandemic phase of COVID-19 (2020–2021). Newly diagnosed patients with pulmonary TB (42,930 before and 32,094 during COVID-19) were included using the national reimbursement data from the health insurance service in Korea. Treatment discontinuation was defined as the discontinuation of treatment for more than 2 weeks during the initial intensive care phase or for more than 2 months during the maintenance phase. Mortality rates were compared before the spread and during the pandemic phase of COVID-19 in all patients and subgroups with various comorbidities. The Kaplan–Meier survival curve for each group of study participants was derived, and collective statistical significance was confirmed using the log-rank test.
Results: The treatment discontinuation rate over the entire period showed a trend of decreasing the time factor (-0.0084), decreasing the level change (-0.0166), and increasing the intersection term (0.0039). These tendencies were similar during the initial intensive care and maintenance treatment periods, suggesting that the decreasing trend over time was significant, but the level change and slope change before the spread and during the pandemic phase of COVID-19 were not in agreement. The total mortality rates increased more during the COVID-19 pandemic (14.6% increase after 1 year and 18.9% increase after 2 years, based on 2020) than before COVID-19 (12.3% increase after 1 year and 16.1% increase after 2 years, based on 2018). Regarding the impact of comorbidities on TB mortality, malnutrition and diabetes showed a strong impact on the mortality with more than 2 of relative risks both in 1-year and 2-year mortalities.
Conclusion: This study verified the clinical impact of the COVID-19 pandemic on TB management. Therefore, establishing appropriate TB management policies is urgently needed for the future COVID-19-like pandemic situation.
Hyun Joo Jung
Ann Clin Microbiol 2025 June, 28(2):8. Published on 4 June 2025.
Effective healthcare policies, such as vaccination, decreased the global prevalence of infectious diseases, such as pertussis. However, these diseases have recently re-emerged, posing a serious public health threat. This article discusses the recent pertussis outbreak in Korea, outlining its clinical symptoms and highlighting the relevant diagnostic tools and management strategies to prevent its re-emergence. Incidence of pertussis in South Korea has been increasing since 2015, with over 30,000 cases reported until November 1, 2024, marking the highest number of cases recorded since the 2000s. Although pertussis is fatal in infants, it can be prevented via maternal vaccination. However, in recent years, pertussis vaccination rate during pregnancy has remained at approximately 60%, which is insufficient to prevent neonatal pertussis. Notably, vaccination rates among adolescents and adults are even lower than those among children, leading to the rapid increase in pertussis infection in the post-adolescent and vulnerable populations. Therefore, effective strategies to promote the vaccination of adults, especially pregnant women, are necessary to prevent and control such re-emerging infectious diseases.
Hae-Sun Chung
Ann Clin Microbiol 2025 June, 28(2):11. Published on 27 June 2025.
Hyun Joo Jung
Ann Clin Microbiol 2025 March, 28(2):8. Published on 4 June 2025.
Effective healthcare policies, such as vaccination, decreased the global prevalence of infectious diseases, such as pertussis. However, these diseases have recently re-emerged, posing a serious public health threat. This article discusses the recent pertussis outbreak in Korea, outlining its clinical symptoms and highlighting the relevant diagnostic tools and management strategies to prevent its re-emergence. Incidence of pertussis in South Korea has been increasing since 2015, with over 30,000 cases reported until November 1, 2024, marking the highest number of cases recorded since the 2000s. Although pertussis is fatal in infants, it can be prevented via maternal vaccination. However, in recent years, pertussis vaccination rate during pregnancy has remained at approximately 60%, which is insufficient to prevent neonatal pertussis. Notably, vaccination rates among adolescents and adults are even lower than those among children, leading to the rapid increase in pertussis infection in the post-adolescent and vulnerable populations. Therefore, effective strategies to promote the vaccination of adults, especially pregnant women, are necessary to prevent and control such re-emerging infectious diseases.
Bosung Park, Mi-Na Kim
Ann Clin Microbiol 2025 June, 28(2):9. Published on 16 June 2025.
Kwangjin Ahn, Hyunju Choi, Taesic Lee, Young Uh
Ann Clin Microbiol 2025 March, 28(2):7. Published on 19 May 2025.
Background: Identifying Bacillus spp. and performing antimicrobial susceptibility testing (AST) is challenging because of their diversity and limited clinical laboratory resources. We investigated the isolation frequency and antimicrobial susceptibility of Bacillus spp. over a 4-year period.
Methods: Bacillus isolates collected between 2020 and 2024 were identified using matrixassisted laser desorption ionization-time of flight mass spectrometry, and AST was performed using the Pos Breakpoint Combo Panel Type 28 (Beckman Coulter).
Results: Species among total isolates (n = 432) were B. cereus (25.1%), B. subtilis (11.8%), B. licheniformis (10.8%), B. pumilus (7.4%), B. simplex (6.9%), B. circulans (6.4%), and B. amyloliquefaciens ssp. plantarum (5.9%). Overall, 65% of all Bacillus isolates were obtained from patients aged ≥ 60 years. The isolation ratios of sterile body fluids, including blood, to non-sterile specimens, in decreasing order, were: B. licheniformis, 4.5; B. subtilis, 2.4; B. pumilus, 2.0; B. amyloliquefaciens ssp. plantarum, 2.0; B. circulans, 1.2; B. thuringiensis, 1.0; B. cereus, 0.76; B. simplex, 0.56; and B. infantis, 0.43. The overall antimicrobial resistance rates were as follows: penicillin, 57.1%; ampicillin, 52.4%; clindamycin, 31.6%; erythromycin, 9.0%; cotrimoxazole, 6.4%; tetracycline, 2.3%; ciprofloxacin, 1.9%; rifampicin, 1.1%; levofloxacin, 0.9%; vancomycin, 0.4%; gentamicin, 0.4%; and imipenem, 0.4%. Penicillin resistance was particularly high in B. thuringiensis (100%), B. cereus (93.5%), and B. licheniformis (71.4%). Clindamycin resistance was high in B. circulans, B. licheniformis, and B. pumilus at 81.8%, 71.4%, and 64.3%, respectively.
Conclusion: Accurate identification and AST of Bacillus spp. are essential when they are isolated from invasive infections, as resistance profiles and isolated species vary significantly depending on the specimens.
Jung-ah Kim, Sae Am Song, Sunjoo Kim, Sunggyun Park, Kwangsook Woo, Yu Kyung Kim
Ann Clin Microbiol 2025 March, 28(2):10. Published on 27 June 2025.
Background: Bacterial antimicrobial resistance (AMR) is a major contributor to the mortality and disease burden associated with bloodstream infections worldwide. The authors investigated the AMR rates of bacterial isolates obtained from blood cultures in 2023 to provide essential baseline data for AMR management and compared these findings with Korea Global Antimicrobial Resistance Surveillance System (Kor-GLASS) (2023) data limited to the first isolate group in our data.
Methods: Through a multicenter survey, we collected AMR data for bacteria causing bloodstream infections in 2023. Sixteen university-affiliated hospitals participated in the survey; nine provided the first isolate data, and seven reported duplicate isolate data. The survey targeted five gram-positive organisms (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Enterococcus faecalis, Enterococcus faecium) and four gram-negative organisms (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa).
Results: Resistance to oxacillin was significantly higher for S. epidermidis (76.9%−83.2%) than S. aureus (39.1%−47.4%), while S. pneumoniae showed 38.9%−51.7% resistance to penicillin. Vancomycin resistance was significantly higher in E. faecium (33.6%−37.8%) than E. faecalis (0.3%). E. coli, K. pneumoniae and P. aeruginosa displayed resistance of 1.1%–1.7%, 10.2%24.9%, and 20.2%–27.3%, respectively, to carbapenems. A. baumannii exhibited carbapenem resistance of 66.3%–87.4%.
Conclusion: Resistance rates among the nine pathogens in this survey were similar to those reported by Kor-GLASS, although K. pneumoniae showed a higher carbapenem resistance rate. Continuous monitoring and antimicrobial stewardship are necessary to reduce the AMR of major pathogens causing bloodstream infections.
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