Evaluation of BacT/Alert FAN Plus Bottles for the Culture of Peritoneal Dialysate

박민승,유인영,On-Kyun Kang,이정은,김대중,허희재,이남용 대한임상미생물학회 2019 Annals of clinical microbiology Vol.22 No.4

Background: A major complication of peritoneal dialysis (PD) is peritonitis, and bacterial culture of PD effluent in a blood culture bottle is the preferred technique for diagnosis of peritonitis. In this study, we compared dialysate inoculation and culture using the BacT/AlerTⓇ Fastidious Antimicrobial Neutralization Plus blood culture bottles (FAN Plus; bioMérieux, France) to the conventional centrifugation culture method. Methods: A total of 170 PD effluents were simultaneously processed by the conventional centrifugation culture method and by culture using FAN Plus media with two different inoculation procedures: inoculation after centrifugation and direct bedside inoculation. Results: Of the 52 cultures that were positive on at least one of the culture methods, 27 samples were positive on conventional centrifugation. However, 46 samples showed growth following inoculation into the FAN Plus media after centrifugation, and 47 samples were positive on the direct FAN Plus inoculation method. Using the case definition for PD peritonitis to classify samples, sensitivity of the conventional method was 50.0% (95% CI, 33.7-66.3%), whereas the sensitivity of the FAN Plus media was 78.9% (95% CI, 62.2-89.9%) by inoculation after centrifugation and 86.8% (95% CI, 71.1-95.1%) by direct inoculation. Use of both inoculation methods with FAN Plus media resulted in 92.1% sensitivity (95% CI, 89.2-99.9%). Conclusion: Culture using FAN Plus media demonstrated a superior bacterial recovery rate to the conventional centrifugation culture method. A combination of the two inoculation methods with FAN Plus media is recommended for the best diagnostic yield, while direct inoculation alone can be useful due to its simplicity and cost-effectiveness. (Ann Clin Microbiol 2019;22:90-95)

Linezolid Resistance in Methicillin-Resistant Staphylococcus aureus in Korea: High Rate of False Resistance to Linezolid by the VITEK 2 System

유인영,On-Kyun Kang,Hyang Jin Shim,허희재,Nam Yong Lee 대한진단검사의학회 2020 Annals of Laboratory Medicine Vol.40 No.1

As various linezolid resistance mechanisms have been identified in methicillin-resistant Staphylococcus aureus (MRSA), we investigated the molecular characteristics of MRSA with elevated linezolid minimum inhibitory concentrations (MICs), using the VITEK 2 system (bioMérieux, Marcy-l’Étoile, France). Twenty-seven MRSA isolates from 14 patients exhibiting linezolid MICs ≥8 μg/mL were examined by broth microdilution (BMD) test as well as by sequencing for mutations in the 23S rRNA gene or ribosomal proteins (L3, L4, and L22) and the presence of the optrA, cfr, and cfr(B) genes. Of the 27 isolates, four (14.8%) from one patient were confirmed as linezolid resistant by BMD and harbored a 23S rRNA T2500A mutation. The remaining 23 were confirmed as linezolid susceptible, indicating that the linezolid-resistant results were major errors generated by VITEK 2. The most commonly detected mutation (19/27, 70.4%), L3 Gly152Asp, was detected in only linezolid-susceptible isolates. No isolates contained optrA, cfr, or cfr(B) or any L4 or L22 protein alterations. Our results show that the 23S rRNA T2500A mutation was mainly associated with linezolid resistance, while the L3 Gly152Asp mutation was not related to linezolid resistance. A confirmatory test is recommended for VITEK 2 linezolid-resistant results owing to the high probability of false resistant results.

Comparison of 16S Ribosomal RNA Targeted Sequencing and Culture for Bacterial Identification in Normally Sterile Body Fluid Samples: Report of a 10-Year Clinical Laboratory Review

In Young Yoo,On-Kyun Kang,Myoung-Keun Lee,김예진,Sun Young Cho,Kyungmin Huh,Cheol-In Kang,Doo Ryeon Chung,Kyong Ran Peck,허희재,Nam Yong Lee 대한진단검사의학회 2020 Annals of Laboratory Medicine Vol.40 No.1

As 16S ribosomal RNA (rRNA)-targeted sequencing can detect DNA from non-viable bacteria, it can be used to identify pathogens from clinical samples even in patients pretreated with antibiotics. We compared the results of 16S rRNA-targeted sequencing and culture for identifying bacterial species in normally sterile body fluid (NSBF): cerebrospinal, pericardial, peritoneal and pleural fluids. Over a 10-year period, a total of 312 NSBF samples were evaluated simultaneously using 16S rRNA-targeted sequencing and culture. Results were concordant in 287/312 (92.0%) samples, including 277 (88.8%) negative and 10 (3.2%) positive samples. Of the 16 sequencing-positive, culture-negative samples, eight showed clinically relevant isolates that included Fusobacterium nucleatum subsp. nucleatum, Streptococcus pneumoniae, and Staphylococcus spp. All these samples were obtained from the patients pretreated with antibiotics. The diagnostic yield of 16S rRNA-targeted sequencing combined with culture was 11.2%, while that of culture alone was 6.1%. 16S rRNA-targeted sequencing in conjunction with culture could be useful for identifying bacteria in NSBF samples, especially when patients have been pretreated with antibiotics and when anaerobic infection is suspected.

최근 10년 동안 일개 상급종합병원의 칸디다혈증 환자에서 분리된 칸디다 균종의 빈도

Yu-Yean Hwang,On-Kyun Kang,Chang-Eun Park,Sung-No Hong,Young-Kwon Kim,Hee-Jae Huh,Nam-Yong Lee 대한임상검사과학회 2022 대한임상검사과학회지(KJCLS) Vol.54 No.2

Candidemia is a major cause of nosocomial infections resulting in increased morbidity and mortality. It remains a serious risk in inpatients and increases medical treatment costs. From 2009 to 2018, Candida strains (3,533) isolated from blood culture tests at the S Hospital were analyzed according to the period, year, sex, age, ward, etc. During the entire period, 54,739 of 717,996 blood culture tests showed a positive rate (7.6%) and the Candida isolation rate was 3,533 (6.4%) out of 1,036 patients. Among the Candida isolates, C. albicans was most common (33.8%), followed by C. tropicalis (28.6%), C. glabrata (19.8%), C. parapsilosis (7.8%), and C. krusei (4.0%). In early (2009∼2013)/late (2014∼2018) isolation, C. tropicalis decreased by 3.8% and C. glabrata increased by 3.4%. After 50 years of age, the higher the separation frequency. C. parapsilosis (31.3%) in 1∼10s, C. tropicalis (30.3%) and C. glabrata (27.6%) in 41∼50s, and C. tropicalis (28.6%) in 80s are relatively frequent. has been separated C. krusei was isolated in a relatively high proportion from females (60.9%). Therefore, a systematic and continuous nosocomial infection control system should be established for appropriate treatment as per antifungal treatment guidelines. The system should continuously monitor the distribution of Candida species and provide rapid identification results. 칸디다혈증(candidemia)은 이환율과 사망률을 높이는 주요 원인으로 입원 환자에서 심각한 위험으로 남아 있으며 의료비용을 증가시킨다. 2009년부터 2018년까지 S병원의 혈액 배양 검사에서 분리된 칸디다 균주 3,533건을 대상으로 시기별 분리빈도, 연도, 성별, 나이, 병동 등에 따라 분석하였다. 전체 기간 중 혈액 배양 의뢰 건수 717,996 중에 54,739건이 배양 양성으로 7.6%의 양성율을 보였으며 칸디다 분리률은 1,036명의 환자에서 3,533건으로 6.4%였다. 균종의 분포는 C. albicans (33.8%), C. tropicalis (28.6%), C. glabrata (19.8%), C. parapsilosis (7.8%), C. krusei (4.0%) 이다. 전기/후기 분리에서는 C. tropicalis가 3.8% 감소하고 C. glabrata 는 3.4% 증가하였다. 50세 이후 연령이 증가할수록 분리 빈도가 높았으며, 1∼10대에서는 C. parapsilosis (31.3%), 41∼50 대에서는 C. tropicalis (30.3%), C. glabrata (27.6%) 순으로, 80대에서는 C. tropicalis (28.6%)가 상대적으로 자주 분리되었다. C. krusei 는 여성(60.9%)에서 상대적으로 높은 비율로 분리되었다. 따라서 Candida 균종의 분포를 지속적으로 감시하고 신속한 동정 결과를 제공하여 적절한 치료 및 항진균제 치료 지침을 위한 체계적이고 지속적인 병원감염관리 시스템이 이루어져야 할 것이다.

2009∼2018년 혈액배양으로부터 분리된 Candida 균종의 항진균제 감수성의 경향

Yu-Yean Hwang,On-Kyun Kang,Chang-Eun Park,Moo-Sik Lee,Young-Kwon Kim,Hee Jae Huh,Nam Yong Lee 대한임상검사과학회 2022 대한임상검사과학회지(KJCLS) Vol.54 No.2

Candida is one of the most common causes of bloodstream infections and a leading cause of morbidity and mortality among hospitalized patients. The purpose of this study was to provide important information for formulating empirical treatment plans for candidemia by investigating the antifungal resistance rate of Candida. Among the Candida strains (973 cases) isolated from blood culture tests at the S hospital in 2009∼2018, 4.7% (N=44) comprising the Candida spp. (932 strains) showed resistance to fluconazole. The resistant strains included C. albicans, C. parapsilosis, C. tropicalis, and C. glabrata. In addition Candida spp. (947 strains) showed resistance to amphotericin B (N=6, 0.6%), flucytosine (N=23, 2.4%) and voriconazole (N=24, 3.1%). C. albicans was resistant to fluconazole (N=23, 6.9%) and voriconazole (N=21, 6.0%), The statistical analysis showed that C. albicans and non-albicans Candida species were resistant to fluconazole (P=0.039) and voriconazole (P<0.001). A monitoring system to understand the rate of candidiasis infections in a hospital setting is required. It is also important to make the right choice of the antifungal agent based on drug susceptibility patterns. Therefore, an infection surveillance policy that tracks Candida resistance through regular antifungal susceptibility tests is necessary. 혈류 감염(BSI)의 주요 원인균의 하나로 입원환자에서 이환율과 사망률을 높이는 칸디다의 항진균제 내성률을 조사하여 칸디다 혈증(candidemia)의 경험적 치료 방침에 중요한 정보를 제공하고자 한다. 2009∼2018년 S병원의 혈액배양 검사에서 분리된 Candida 균주(973건) 중 Candida spp. (932 균주)에 대한 fluconazole 감수성 시험결과에서 4.7% (N=44)가 내성(resistant, R)을 보였고 C. albicans, C. parapsilosis, C. tropicalis, C. glabrata에서 내성 균주를 확인하였다. 또한, Candida spp. (947 균주)의 amphotericin B에 대한 감수성 결과에서는 내성(N=6, 0.6%)이 나타났고, 전체 Candida spp. (973 균주)에 대한 flucytosine 감수성 시험에서는 내성(N=23, 2.4%)을 보였다. Candida spp. (768 균주)의 voriconazole에 대한 감수성 시험에서는 내성(N=24, 3.1%)을 보였다. C. albicans는 fluconazole (N=23, 6.9%), voriconazole (N=21, 6.0%)이 내성이고 통계학적으로 C. albicans과 non-albicans Candida species은 fluconazole (P=0.039), voriconazole (P<0.001)로 나타났다. 칸디다 혈증의 감염률을 이해하고 예방하기 위한 감시 시스템이 요구되고 항진균제의 적절한 투여와 치료가 요구된다. 따라서 항진균제 감수성 결과의 모니터링을 통한 칸디다의 내성을 추적하는 감염감시활동 정책이 필요할 것으로 사료된다.

Diagnostic Performance of the GENEDIA MTB/NTM Detection Kit for Detecting Mycobacterium tuberculosis and Nontuberculous Mycobacteria With Sputum Specimens

Sunghwan Shin,유인영,Hyang Jin Shim,On-Kyun Kang,Byung Woo Jhun,Won-Jung Koh,허희재,Nam Yong Lee 대한진단검사의학회 2020 Annals of Laboratory Medicine Vol.40 No.2

The GENEDIA MTB/NTM Detection Kit (GENEDIA MTB/NTM; Green Cross Medical Science Corp., Chungbuk, Korea) is a multiplex real-time PCR assay used for differential identification of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM). While the importance of differential identification of MTB/NTM is recognized, there is limited data on the performance of GENEDIA MTB/NTM assay to date. A total of 687 consecutive sputum specimens were cultured and analyzed with the GENEDIA MTB/NTM and GENEDIA MTB assays. Nineteen specimens (2.8%) were MTBC-positive, and 69 (10.0%) were NTM-positive based on mycobacterial culture. All specimens showed concordant results for MTBC using both assays, with a kappa value of 1.00, overall sensitivity of 63.2% (12/19), and specificity of 100% (668/668). The overall NTM sensitivity and specificity were 23.2% (16/69) and 99.7% (616/618) for GENEDIA MTB/NTM. The association between NTM-positivity using GENEDIA MTB/NTM and the diagnosis of NTM pulmonary disease was not statistically significant. In conclusion, the two real-time PCR assays showed similar diagnostic performance for MTBC detection. However, the sensitivity for NTM detection was lower than that for MTBC detection.

Enhancement of the Biomass, Protein, and Phycocyanin Production from Spirulina maxima in Mass Cultivation by Adding Magma Seawater from Jeju Island, Korea

In Yung SUNWOO,Woon Yong CHOI,Eun-Jeong GO,Yong Kyun RYU,Won Kyu LEE,Tae Ho KIM,Areumi PARK,Yeon-Ji LEE,Soe On AHN,Do-Hyung KANG 한국생물공학회 2023 한국생물공학회 학술대회 Vol.2023 No.4

First Case of Bacteremia Caused by Coprobacillus catenaformis

Won Young Heo,Jong Kwon Lee,Yoo Na Chung,In Young Yoo,On-Kyun Kang,Duk Hyun Sung,Sun Young Cho,Hee Jae Huh,Nam Yong Lee 대한진단검사의학회 2020 Annals of Laboratory Medicine Vol.40 No.5