Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology

6

Weeks in Review

2

Weeks to Publication
Indexed in KCI, KoreaMed, Synapse, DOAJ
Open Access, Peer Reviewed
pISSN 2288-0585 eISSN 2288-6850

September, 2022. Vol. 25 No. 3.

Mini review

EUCAST v.12.0 review focused on changes

 Sae Am Song

Ann Clin Microbiol 2022 September, 25(3): 67-72. Published on 20 September 2022.

Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoint tables are commonly used as guidelines for the interpretation of antimicrobial susceptibility testing results. These are updated annually to reflect new and revised antimicrobial susceptibility breakpoints. EUCAST v.12.0, which was published in January 2022, presents updated meropenem-vaborbactam breakpoints for Enterobacterales and Pseudomonas aeruginosa. It also suggests new breakpoints of susceptibility to various antibiotics for Vibrio spp. Flow charts were updated for Streptococcus pneumoniae and Haemophilus influenzae, and the breakpoints for anaerobic bacteria were divided according to each species. Furthermore, recommendations were made for cases without antimicrobial susceptibility testing breakpoints and links to several rationale and guidance documents were provided for technical convenience.

[in Korean]

Original article

On-field evaluation of exdia COVID-19 antigen point-of-care testing in the emergency department during the COVID-19 pandemic

In Young Yoo, Gun Dong Lee, Hyojin Chae, Chun Song Youn, Eun-Jee Oh, Yeon-Joon Park

Ann Clin Microbiol 2022 September, 25(3): 73-78. Published on 20 September 2022.

Background: We evaluated the diagnostic performance of the Exdia COVID-19 antigen test (Exdia Ag; Precision Biosensor Inc., Korea) as a point-of-care (POC) test performed in the emergency department (ED) for the rapid detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in comparison with the performance of the Real-Q 2019-nCoV Detection KIT (Real-Q; BioSewoom, Korea).

Methods: Exdia Ag and Real-Q assays were performed simultaneously for all patients who were admitted to the ED of Seoul St. Mary’s Hospital with or without COVID-19 symptoms between December 2021 and March 2022.

Results: Among the 2,523 samples analyzed by Real-Q assay, 149 samples (5.9%) showed positive results, and 2,374 samples showed negative results. The overall sensitivity and specificity of the Exdia Ag assay were 77.2% (95% confidence interval [CI], 69.6 – 83.7) and 99.8% (95% CI, 99.6 – 99.9), respectively. The positive and negative predictive values were 96.6% (95% CI, 91.5 – 98.7) and 98.6% (95% CI, 98.1 – 98.9), respectively. The cycle threshold value for 115 concordant Exdia Ag-positive/Real-Q-positive samples was significantly lower than that for 34 discordant Exdia Ag-negative/Real-Q-positive samples (P < 0.0001).

Conclusion: The Exdia Ag assay showed good diagnostic performance when the disease prevalence was high and may be useful for POC testing when the rapid detection of SARSCoV-2 is required for the isolation of patients in the ED.

Original article

Antimicrobial susceptibility patterns and clinical characteristics of Corynebacterium striatum cases from 2018 to 2021

Inho Choi, Yangsoon Lee

Ann Clin Microbiol 2022 September, 25(3): 79-84. Published on 20 September 2022.

Background: Corynebacterium striatum is part of the normal flora of the skin, oral cavity, and intestine. However, it can be a pathogen causing endocarditis, pneumonia, arthritis, and meningitis occasionally. We evaluated the clinical features and antimicrobial susceptibility pattern of C. striatum cases.

Methods: Patients infected with C. striatum, who consulted infectious disease physicians and were admitted to Hanyang University hospital between January 2018 and January 2021, were enrolled for an antimicrobial susceptibility test (AST). We reviewed medical records of selected patients for information on diagnosis, specimen types, and antibiotics used before and after AST. AST was performed using E-test and interpreted according to the Clinical and Laboratory Standards Institute M45 guidelines.

Results: A total of 23 cases were evaluated, and average age of patients was 58.5 years. Ten cases were diagnosed sepsis. Eight cases were complicated with cancer, and five cases had wound infections. Four cases were treated with vancomycin prior to AST; in 13 cases, antibiotics were switched to vancomycin after AST. Resistance rates were highest for ciprofloxacin (93.3%), which was followed by cefotaxime (92.3%), penicillin G (87.0%), erythromycin (87.0%), trimethoprim/sulfamethoxazole (78.3%), and meropenem (76.5%).

Conclusion: The patients infected by C. striatum were old and immunosuppressed, while many had cancer. Since C. striatum shows resistance to most drugs except vancomycin, we should consider conducting AST prior to antibiotic treatment.

Original article

Antibody detection in healthcare workers after vaccination with two doses of the BNT162b2 or ChAdOx1 vaccine

Kyoung Ho Roh, Heun Choi, HeeKyoung Choi, Miseon Yoon, Jongha Yoo, Yoonseon Park

Ann Clin Microbiol 2022 September, 25(3): 85-95. Published on 20 September 2022.

Background: Due to the COVID-19 pandemic, from 2020, many pharmaceutical companies have developed vaccines. To determine the efficacy of AstraZeneca’s and Pfizer’s vaccines, which were the first and second vaccines to be approved in Korea, respectively, we developed a method to measure their antibody-generating efficacies using immunology analyzers and a rapid antibody test available in Korea.

Methods: The antibody-stimulating efficacies of the Pfizer and AstraZeneca vaccines were evaluated using Centaur® XPT SARS-CoV-2 (Siemens Healthineers, Germany), Elecsys® AntiSARS-CoV-2 S (Roche Diagnostics, Germany), and STANDARD F SARS-CoV-2 nAb FIA (SD Biosensor, Korea). Healthcare workers were enrolled in two groups: the Pfizer (121) and AstraZeneca (117) groups. Antibody levels were measured pre-vaccination, three weeks after vaccination, and 16 weeks after vaccination.

Results: The Pfizer group comprised 41 males and 80 females, while the AstraZeneca group comprised 38 males and 79 females. Antibody results were analyzed after excluding four individuals who had recovered from COVID-19. Between weeks 3 and 16, there was no significant difference (P = 0.5, 1.0) between the results of the Roche and Siemens antibody tests in the Pfizer vaccine group. However, the SD biosensor results comparing with the Roche and Siemens antibody tests at three weeks after the initial vaccination showed a significant difference (P < 0.0001). Analysis of the Roche antibody test results before, at three weeks, and at 16 weeks after the administration of the Pfizer and AstraZeneca vaccines revealed a statistically significant difference between before and at three weeks after the first injection (P < 0.0001).

Conclusion: After two doses of the Pfizer and AstraZeneca vaccines, antibody formation was above the 90th percentile of the measurement range in all subjects.

Case report

A 59-year-old man with bacteremia caused by Bordetella hinzii in Korea: a case report

Joonsang Yu, Sihwan Kim, Kyu-Hwa Hur, Heungsup Sung, Mi-Na Kim

Ann Clin Microbiol 2022 September, 25(3): 97-102. Published on 20 September 2022.

Bordetella hinzii is a nonfermenting, gram-negative rod and a rare opportunistic pathogen that can cause respiratory infections, bacteremia, and cholangitis. Here, we report the first case of bacteremia caused by B. hinzii in Korea. A 59-year-old man was admitted for the biopsy of a mass lesion in the left lower lobe, which was detected during a health screening. The blood cultures collected from the patient with high fever (> 39℃), which developed 4 hours after the biopsy, yielded gram-negative rods. The gram-negative bacilli were identified as B. hinzii using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and PCR sequencing of the 16S rRNA gene. After 9 days of antimicrobial treatment with ampicillin/sulbactam, piperacillin/tazobactam, or meropenem, the patient improved and was discharged.

Letter to the editor

Laboratory indicators for convalescence in SARS-CoV-2 positive cases with high Ct value

Rae Na, Kuenyoul Park, Heungsup Sung, Mi-Na Kim

Ann Clin Microbiol 2022 September, 25(3): 103-107. Published on 20 September 2022.