Seon A Jo, Sang Hyuk Ma, Seungjun Lee, Sunjoo Kim
Ann Clin Microbiol 2020 September, 23(3): 117-124. Published on 20 September 2020.
Background: Pharyngitis is one of the most common conditions encountered in primary health care facilities. Accurate differentiation of group A streptococcus (GAS) infection from viral infection is difficult. The STANDARD F Strep A Ag FIA (SD BIOSENSOR, Korea) is a rapid antigen detection test (RADT) that has been recently developed for diagnosing GAS pharyngitis. In this study, we evaluated the diagnostic performance of the STANDARD F Strep A Ag FIA and compared the results between the RADT and conventional throat culture.
Methods: Throat swab samples were obtained from a total of 372 children presenting pharyngitis symptoms in five pediatric clinics in Changwon, Korea from July 2018 to October 2019. A comparative study between STANDARD F Strep A Ag FIA and Sofia Strep A FIA (Quidel, USA) was performed. Two throat swabs were taken simultaneously from each patient for RADT. The third throat swab was stored in a transport tube containing Stuart’s transport medium for culture. Performance and kappa index of STANDARD F Strep A Ag FIA were evaluated.
Results: GAS infection was detected in 29.3% (109/372) patients, using the STANDARD F Strep A Ag FIA. The sensitivity, specificity, positive predictive value, and negative predictive value were 95.0%, 95.2%, 88.1%, and 98.1%, respectively. The STANDARD F Strep A Ag FIA showed an excellent concordance rate of 96.5% and a kappa value of 0.89 compared to Sofia Strep A FIA.
Conclusion: The STANDARD F Strep A Ag FIA demonstrated an excellent performance along with Sofia Strep A FIA for the diagnosis of GAS pharyngitis.
[in Korean]
Justin Mugiraneza, Mijung Kwon, Daewon Kim, Sang-Guk Lee, Hyukmin Lee, Dongeun Yong
Ann Clin Microbiol 2020 September, 23(3): 125-134. Published on 20 September 2020.
Background: The rapid antimicrobial susceptibility testing (AST) performed on urine samples would guide the adequate choice of antibiotics for obtaining better treatment outcomes in patients. Our study aimed to evaluate the performance of the modified-EUCAST (European Committee on Antimicrobial Susceptibility Testing) rapid direct AST on urine samples.
Methods: From >2,000 urine samples, a total of 128 urine samples containing bacterial counts of ≥2 × 104 CFU/mL with a uniform bacterial shape were initially included based on flow cytometry (Sysmex UF-1000i, Japan) and Gram staining, respectively. A total of 103 samples showing the presence of Enterobacteriaceae were finally selected in this study. The urine samples were directly inoculated on Mueller-Hinton agar, which was used in the current EUCAST rapid direct AST on blood samples. The size of the growth inhibition zones around antimicrobial disks was measured using a digital scanner (BIOMIC vision analyzer, Giles scientific, USA) and further confirmed by visualization with naked eyes after incubation for 4, 6, and 8 hours. The AST interpretations were compared to those of the conventional VITEK 2 AST system (bioMérieux, France) and the discrepancies between both tests were confirmed with the E-test.
Results: The antibiotics, namely ampicillin, cefazolin, aztreonam, ceftazidime, cefotaxime, cefoxitin, cefepime, gentamicin, ciprofloxacin, and cotrimoxazole showed excellent correlations with modified-EUCAST rapid direct test and conventional ASTs with >0.75 weighted kappa values. The categorical agreement of the rapid direct AST was 1,442 (93.3%), with 76 (4.9%) minor error, 9 (0.6%) major error and 18 (1.2%) very major error, implicating the reliability of this method for clinical application.
Conclusion: Performing the modified-EUCAST rapid direct AST on urine samples can predict reliable AST results within 8 hours. The rapid direct AST can help the physicians to initiate adequate antimicrobial treatment for urinary tract infections.
Changseung Liu, Eunjung Lee, Dokyun Kim, Seok Hoon Jeong
Ann Clin Microbiol 2020 September, 23(3): 135-148. Published on 20 September 2020.
Background: We evaluated the performance of ASTA MicroIDSys (ASTA, Korea) and Bruker Biotyper (Bruker Daltonics, Germany) systems in the identification of bacterial isolates from clinical microbiology laboratory specimens during the study period. In addition, species for which the identification accuracy using MALDI-TOF MS systems was previously reported to be poor were also identified by comparing the MS results with those obtained using molecular identification.
Methods: A total of 889 non-duplicated clinical isolates were included in this study. The results of ASTA MicroIDSys were compared with those of Bruker Biotyper; 16S rRNA sequencing was performed for the species for which results obtained using the two systems did not match. The sequences of rpoB, hisA, and/or recA for the clinical isolates of Acinetobacter species, Klebsiella species, and Burkholderia cepacia complex were analyzed and used as reference identifications.
Results: The concordance rates for bacterial identification using ASTA MicroIDSys and Bruker Biotyper were 100% at the genus level and 98.3% at the species level for isolates belonging to the order Enterobacterales. Similarly, the concordance rates at the genus and species levels were 98.8% and 91.0% for glucose non-fermenting bacilli, 100% and 100% for gram-positive cocci, and 98.9% and 98.9% for other isolates, respectively. ASTA MicroIDSys was expected to correctly identify 97.9% of the 108,251 isolates identified in our clinical microbiology laboratory over the past 5 years.
Conclusion: ASTA MicroIDSys showed excellent performance in bacterial identification for most of the clinically relevant species. Further extension of the database could improve the identification accuracy of ASTA MicroIDSys.
[in Korean]
In Hwa Jeong, Gyu Dae Ahn, Namhee Kim, Kyung Hee Kim, Sang Dong Shin, Jin Yeong Han, Gwang Sook Woo
Ann Clin Microbiol 2020 September, 23(3): 149-153. Published on 20 September 2020.
Carnobacterium is a genus of gram-positive bacilli belonging to the family Lactobacillaceae. Generally, Carnobacterium species are considered nonpathogenic to humans and are mostly found in the natural environment, food, and food packaging. Furthermore, some Carnobacterium species play a bioprotective role in the food industry. Isolation of Carnobacterium from human blood or other sites, such as skin or abscess, has rarely been reported—there are only four published case reports worldwide, and none of them is from Korea. In all the reported cases, the patients reported contact with an aqueous environment or were administered nutrition via a parenteral route. Herein, we report the detection of Carnobacterium divergens bacteremia in an immunocompromised patient by using mass spectrometry in Korea.
Jaewoong Lee, Hyunjung Kim, Hae Kyung Lee, Yeon-Joon Park
Ann Clin Microbiol 2020 September, 23(3): 155-158. Published on 20 September 2020.
Probiotics are used to restore and maintain the healthy intestinal microflora. Although Saccharomyces cerevisiae (SC) is considered as a non-pathogenic yeast, administration of SC as a probiotic is associated with a rare cause of fungemia in immunocompromised patients with central venous catheter insertion. We encountered a case of SC fungemia in a premature infant who presented with respiratory distress syndrome and had undergone central venous catheterization.
Young Ah Kim, Hyunsoo Kim, Chulhun L. Chang
Ann Clin Microbiol 2020 September, 23(3): 159-163. Published on 20 September 2020.
The Coronavirus Disease 19 (COVID-19), which emerged as pneumonia from an unknown agent for the first time at the end of 2019, has dramatically transformed our world into one that is highly unrecognizable today. Newly emerging infectious diseases have been occurring more frequently than ever. Opportunities of such deadly microorganisms to adapt to humans—as well as spread between people on a massive scale—are growing because of active human mobility. We have translated and published the book, “One Health: People, Animals, and the Environment.” The original book, published in 2014 by ASM Press, shows the concept and applications of One Health. The current book comprises five parts: definition and importance of One Health, zoonotic and environmental drivers of emerging infectious diseases, One Health and antibiotic resistance, disease surveillance, and realizing the One Health Initiative’s objectives. This translation and publication was the first science book publishing project performed under the name of the Korean Society of Clinical Microbiology. We are actively working toward providing academic information and advancing our identity in other scientific fields as well as to the public.
[in Korean]
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