Kristin Widyasari, Sunjoo Kim
Ann Clin Microbiol 2023 September, 26(3):41-50. Published on 20 September 2023.
Group B Streptococcus (GBS, Streptococcus agalactiae) is a pathogen that causes sepsis and meningitis, particularly in newborns, as well as severe infections in the elderly and those at high risk. For many years, the administration of intrapartum antimicrobial prophylaxis (IAP) has been a standard method to prevent neonatal GBS infection. However, IAP may be unsuitable in low-income settings due to its high cost and difficult accessibility to medical institutions. Additionally, IAP may lead to the emergence of antimicrobial-resistant bacteria. Hence, an alternative method for the control of GBS, such as a vaccine, is needed. An effective vaccine will likely prevent the further spread of GBS and be cost-effective compared with IAP. GBS vaccines have been under development for the past two decades, and several candidates have shown potential. In this review, we discuss the current development of GBS vaccines, including types and their implementation in different target populations.
Jae-Woo Chung
Ann Clin Microbiol 2023 September, 26(3):51-57. Published on 20 September 2023.
Clinical and Laboratory Standards Institute (CLSI) M100 ‘Performance Standards for Antimicrobial Susceptibility Testing (AST)’ and the European Committee on AST (EUCAST) ‘Breakpoint tables for interpretation of MICs and zone diameters’ guidelines for conducting and interpreting AST are revised yearly. The 2023 CLSI guideline introduces selective and cascade reporting methods for antibacterial agents as a part of strengthening antibiotic stewardship and changes in breakpoints for aminoglycoside (AG) in Enterobacterales and AG and piperacillin in Pseudomonas aeruginosa. Main changes in EUCAST include revised breakpoints for aminopenicillins in Enterobacterales, and detailed criteria reflecting the clinical situation and antibacterial agent administration method.
[in Korean]
Jae Kwang Lee, Yoonseon Park, Young Ah Kim
Ann Clin Microbiol 2023 September, 26(3):59-66. Published on 20 September 2023.
Background: This study aims to analyze the risk factors for urinary tract infection (UTI) by cefotaxime-resistant Escherichia coli or Klebsiella pneumoniae, using data from the National Health Insurance Data Sharing Service.
Methods: A retrospective case-control study was conducted to analyze the risk factors during 11 years (2010–2020). Study groups were selected based on the laboratory data of the hospital, which comprised 3,638 and 877 cases of cefotaxime-resistant E. coli and K. pneumoniae, respectively. Controls comprised 8,994 and 1,573 cases of cefotaxime-nonresistant (intermediate or susceptible) E. coli and K. pneumoniae, respectively. Clinical and socioeconomical features were obtained from the National Health Insurance service data.
Results: In a multivariate analysis of risk factors for UTI by cefotaxime-resistant E. coli, the odds ratio (OR) of the male sex was 1.335 (95% confidence interval, 1.204–1.480), age 0–9 years was 1.794 (1.468–2.191), chronic renal disease was 1.227 (1.062–1.417), and hemodialysis was 1.685 (1.255–2.262). Moreover, the ORs of L-tube, central venous pressure catheter, and Foley catheter use were 1.204 (1.047–1.385), 1.332 (1.156–1.534), and 1.473 (1.316–1.649), respectively; the OR of previous antimicrobial use was 1.103 (1.009–1.206) and that of healthcare facility use was 1.782 (1.576–2.014). In a multivariate analysis of risk factors for UTI by cefotaxime-resistant K. pneumoniae, OR of the male sex was 1.460 (1.199–1.778), liver disease was 1.295 (1.037–1.617), and hemodialysis was 2.046 (1.263–3.315). The ORs of L-tube and Foley catheter use were 2.329 (1.861–2.915) and 1.793 (1.431–2.246), respectively, and the OR of the healthcare facility use was 1.545 (1.161–2.056).
Conclusion: In this study, the risk factors for UTI caused by cefotaxime-resistant E. coli or K. pneumoniae were analyzed based on the data of a specific healthcare facility linked to the National Health Insurance system. We suggest that it is a simple and effective way to elucidate risk factors of infections caused by major antimicrobial-resistant pathogens.
Changseung Liu, YeJin Oh, Young Jin Ko, Mi Hyun Bae, Jung-Hyun Byun, Eun Jeong Won
Ann Clin Microbiol 2023 September, 26(3):67-73. Published on 20 September 2023.
Background: Intestinal protozoa are potential diarrhea-causing pathogens and monitored worldwide. The Korea Centers for Disease Control and Prevention has also been monitoring intestinal protozoa causing diarrhea for many years. Recently, the overall protozoa detection rate has decreased to less than 1%, but whether protozoa infection causing diarrhea has declined or is being underestimated has not been studied. This study aimed to investigate the molecular epidemiology of intestinal protozoan pathogens in stool samples collected from multiple Korean centers.
Methods: Stool samples were collected from five university hospitals and a commercial laboratory. Direct smear and trichrome staining were performed on all samples. The presence of Cryptosporidium parvum, Giardia lamblia, Entamoeba histolytica, Cyclospora cayetanensis, Dientamoeba fragilis, and Blastocystis hominis were detected using Allplex™ Gastrointestinal Parasite Assays (Seegene Inc., Korea). Microsporidia species and Kudoa septempunctata were detected using PowerChek™ Microsporidia Multiplex and Kudoa Real-time PCR kits (Kogene Biotech, Korea), respectively.
Results: The collected samples included 279 diarrheal and 51 non-diarrheal samples. Among the 279 diarrheal samples, nine samples [B. hominis (n=7), C. parvum (n=1), and Microporidia species (n=1)] were positive, but there were no positive samples for K. septempunctata. We could not detect any protozoa by direct smear and trichrome staining. Among the 51 nondiarrheal samples, 10 (19.6%) samples were positive for B. hominis, but no other protozoa were observed.
Conclusion: This multicenter study showed that the detection rate of intestinal protozoa is currently low in diarrheal samples from Korea. However, B. hominis was frequently detected in non-diarrheal samples, indicating their low pathogenicity.
Hae-Sun Chung, You Sun Kim, Young-Seok Cho, Jeong Su Park, Bo-Moon Shin
Ann Clin Microbiol 2023 September, 26(3):75-82. Published on 20 September 2023.
Background: This study aimed to investigate perceptions of Clostridioides difficile infection (CDI) diagnostic tests among physicians who prescribe CDI diagnostic tests as part of providing direct patient care.
Methods: In August 2018, we provided a 12-question survey of gastroenterologists (the most common referral source for CDI testing) to 35 medical institutions in Korea, asking them about their perceptions of CDI diagnosis and testing.
Results: A comparison of the perceptions of physicians and clinical pathologists (CPs) found that physicians had a lower perceived sensitivity of the toxin AB enzyme immunoassay test. For nucleic acid amplification tests, physicians exhibited a perception of higher assay sensitivity and specificity than CPs. The specificity of culture tests was generally perceived as high by physicians, whereas CPs regarding expressed mixed opinions. All but one physician and one CPs found the algorithmic test useful. Concerning the CDI isolation criteria, physicians commenced patient isolation by concurrently assessing both test results and clinical symptoms, rather than exclusively relying upon test results. Among CPs, 84.6% said they could rely on symptoms to determine when to release a patient from isolation, while 46.2% of physicians said they would rely on test results.
Conclusion: This study provides useful information on the status of laboratory diagnosis of CDI in Korea and what needs to be improved, which will help to standardize and improve laboratory diagnosis of CDI in Korea.
[in Korean]
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