Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology
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.
Kwangjin Ahn, Hyunju Choi, Taesic Lee, Young Uh
Ann Clin Microbiol 2025 June, 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.
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.
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