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.

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.

robust sliding mode controller design for a ball screw table driven by an air motor

Yu-Ta Shen,Yean-Ren Hwang,Chia-Sheng Cheng 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.11

Air motors are often applied in the automation industry in areas with special requirements, such as in sparkprohibited environments, the mining industry, chemical manufacturing plants, and similar locations. The purpose of this study is to analyze the behaviors of a ball screw table powered by a vane-type air motor and to design a robust sliding mode controller for the inlet pressure. The rotational speed of the air motor is closely related to the pressure and flow rate of the compressed air. Furthermore, the compressibility of the air and the friction in the mechanism mean that the overall system is nonlinear, with fluctuating input. A robust sliding mode control is developed to overcome the effects of variations in the inlet pressure and air leakage problems. The experimental results validate the robustness of the proposed position control strategy.

Application of cepstrum and neural network to bearing fault detection

Yean-Ren Hwang,Kuo-Kuang Jen,Yu-Ta Shen 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.10

This paper proposes an integrated system for motor bearing diagnosis that combines the cepstrum coefficient method for feature extraction from motor vibration signals and artificial neural network (ANN) models. We divide the motor vibration signal, obtain the corresponding cepstrum coefficients, and classify the motor systems through ANN models. Utilizing the proposed method, one can identify the characteristics hiding inside a vibration signal and classify the signal, as well as diagnose the abnormalities. To evaluate this method, several tests for the normal and abnormal conditions were performed in the laboratory. The results show the effectiveness of cepstrum and ANN in detecting the bearing condition. The proposed method successfully extracted the corresponding feature vectors, distinguished the difference, and classified bearing faults correctly.

Dynamic Modeling and Controller Design for Air Motor

Yu-Da Shen,Yean-Ren Hwang 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Fuzzy MRAC controller design for vane-type air motor systems

Yean-Ren Hwang,Yu-Da Shen,Kuo-Kuang Jen 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.3

Air motors are widely used in the automation industry due to special requirements, such as spark-prohibited environments, the mining industry, chemical manufacturing plants, and so on. The purpose of this paper is to analyze the behavior of a vane-type air motor and to design a model reference adaptive control (MRAC) with a fuzzy friction compensation controller. It has been noted that the rotational speed of the air motor is closely related to the compressed air’s pressure and flow rate, and due to the compressibility of air and the friction in the mechanism, the overall system is actually nonlinear with dead-zone behavior. The performance of the previous controllers implemented on an air motor system demonstrated a large overshoot, slow response and significant fluctuation errors around the setting points. It is important to eliminate the dead-zone to improve the control performance. By considering the effects of the dead-zone behavior, we have developed an MRAC with fuzzy friction compensation controller to overcome the effect of the dead-zone. The following experimental results are given to validate the proposed speed control strategy.

Dynamic analysis and fuzzy logic control for the vane-type air motor

Yean-Ren Hwang,Yu-Ta Shen,Min-Shin Chen 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.12

Air motors are widely used in the automation industry with special requirements, such as park-prohibited environments, mining, chemical manufacturing, and so on. However, during the past only few literatures discussed the dynamics of air motors or their control strategies. The purpose of this paper is to analyze the dynamics of a vane-type air motor, and design a fuzzy logic controller. It is found that the rotational speed of the air motor is strongly affected by the pressure and flow rate of the compressed air. Further, due to the mechanical friction, the overall system is actually nonlinear with dead-zone and has hysteretic behavior. The performance of conventional PI controllers implemented on the air motor usually results in large overshoot, slow response and significant fluctuation errors. To cope with the nonlinear effects of dead-zone and hysteretic behavior, we developed a fuzzy logic controller to improve the performance. The experimental results show that the proposed controller can effectively control the system with a settling time within 0.2 second, the error fluctuation less than 0.5% for high speed operation and 1.5% for low speed operation, and without any overshoot.

비뇨생식기계 검체로부터 분리된 Ureaplasma 종의 Fluoroquinolone 내성과 관련된 gyrA, gyrB, parC, parE 유전자의 돌연변이 양상

조은정 ( Eun Jung Cho ),황유연 ( Yu Yean Hwang ),구본경 ( Bon Kyeong Koo ),박제섭 ( Jesoep Park ),김영권 ( Young Kwon Kim ),김성현 ( Sunghyun Kim ) 대한임상검사과학회 2016 대한임상검사과학회지(KJCLS) Vol.48 No.2

Fluoroquinolone 계 항생제의 광범위한 사용으로 인해 이 약제에 대한 내성 Ureaplasma 종의 분리 비율이 높아지고 있다. Fluoroquinolone 계 항생제 내성은 주로 DNA gyrase와 topoisomerase IV 유전자의 돌연변이로 인해 발생하는 것으로 알려져 있다. DNA gyrase는 A와 B 2개의 소단위로 이루어져 있으며, gyrA와gyrB 유전자에 의해 암호화되어 있고, Topoisomerase IV는 parC와 parE 유전자에 의해 암호화되어 있다. 본 연구가 진행된 서울의 1개 3차 병원에서 2012년부터 2013년까지 1년동안 Ureaplasma 종의 fluoroquinolone 계 항생제인 OFL과 CIP의 항생제검사 감수성 결과를 분석한 결과 내성과 중등도를 합산할 경우 66.08%, 92.69%로 매우 높은 내성 비율을 보였다. 이에 Ureaplasma 종을 OFL과 CIP에 대한 감수성을 기준으로 4개 그룹으로 분류하여 gyrA, gyrB, parC, parE 유전자의 돌연변이 여부를 검사하여 항생제 내성과의 관련성을 밝히고자 하였다. 그 중 parC 유전자의 돌연변이 빈도가 높아 topoisomerase IV의 돌연변이가 fluoroquinolone계 약제에 대한 내성과 밀접한 관련이 있음을 확인할 수 있었다. 본 연구를 통해 GyrB의 Asn481Ser, ParC의 Phe149Leu, Asp150Met, Asp151Ile, Ser152Val, ParE의 Pro446Ser, Arg448Lys을 추가로 발견할 수 있었다. 최근 fluoroquinolone 계 항생제의 사용이 증가하고 있기 때문에 추후 Ureaplasma 종의 fluoroquinolone계 항생제 내성에 대한 지속적인 모니터링이 필수적일 것으로 사료되며, 이와 관련한 유전자의 돌연변이 양상과의 상관관계를 분석하여 기존 배양검사의 단점을 보완할 수 있는 분자 진단학적 검사법의 추가적인 분석이 필요할 것으로 사료된다. Ureaplasma species can normally colonize in the bodies of healthy individuals. Their colonization is associated with various diseases including non-gonococcal urethritis, chorioamnionitis, neonatal meningitis, and prematurity. In 2012, the sum of the resistant and intermediate resistant rates of Ureaplasma spp. to ofloxacin and ciprofloxacin was 66.08% and 92.69%, respectively. DNA point mutations in the genes encoding DNA gyrase (topoisomerase II) and topoisomerase IV are commonly responsible for fluoroquinolone resistance. Each enzyme is composed of two subunits encoded by gyrA and gyrB genes for DNA gyrase and parC and parE genes for topoisomerase IV. In the current study, these genes were sequenced in order to determine the role of amino acid substitutions in Ureaplasma spp. clinical isolates. From December 2012 to May 2013, we examined mutation patterns of the quinolone resistance-determining region (QRDR) in Ureaplasma spp. DNA sequences in the QRDR region of Ureaplasma clinical isolates were compared with those of reference strains including U. urealyticum serovar 8 (ATCC 27618) and U. parvum serovar 3 (ATCC 27815). Mutations were detected in all ofloxacin- and ciprofloxacin- resistant isolates, however no mutations were detected in drug-susceptible isolates. Most of the mutations related to fluoroquinolone resistance occurred in the parC gene, causing amino acid substitutions. Newly found amino acid substitutions in this study were Asn481Ser in GyrB; Phe149Leu, Asp150Met, Asp151Ile, and Ser152Val in ParC; and Pro446Ser and Arg448Lys in ParE. Continuous monitoring and accumulation of mutation data in fluoroquinolone-resistant Ureaplasma clinical isolates are essential to determining the tendency and to understanding the mechanisms underlying antimicrobial resistance.

감염관리 분야에서 감시배양검사의 표준화 연구

박창은 ( Chang-eun Park ),정나연 ( Na-yeon Jeong ),양민지 ( Min-ji Yang ),김한울 ( Han-wool Kim ),주세익 ( Sei-ick Joo ),김건한 ( Keon-han Kim ),성희경 ( Hee-kyung Seong ),황유연 ( Yu-yean Hwang ),임현미 ( Hyun-mi Lim ),손재철 ( J 대한임상검사과학회 2018 대한임상검사과학회지(KJCLS) Vol.50 No.3

의료 관련 감염을 예방하기 위한 필수적 방법은 일관성이 있는 감염감시 시스템을 구축하고 효율적인 감시 통제를 수행하기 위해 신뢰할 수 있는 상황에 대해 진단을 향상시켜나가는 것이다. 또한 의료 종사자의 손과 의복 및 장비는 환자 관리 및 환경과 접촉하여 병원체가 오염되는 요인이다. 병원체를 가진 시설 표면(예: 침대 레일, 침대 옆 탁자), 음용수, 냉각탑용수, 내시경기구, 급식위생, 공기매개, 멸균검사, 내독소검사, 및 의료 장비를 포함한 의료 환경의 오염은 일반적으로 발생한다. 또한 이러한 감염원을 활동 감시를 통해 MLST, PFGE의 기법으로 역학 분석을 수행한다. 따라서 HAI 예방을 위한 환경 감시배양 검사는 환자의 안전과 감염원의 차단을 향상시킬 뿐만 아니라 국가의 감염관리 시스템을 통제하여 최적의 효율적인 감염관리 예방을 가능케 하고 국가의 감염관리 시스템의 안전을 향상시킨다. 결론적으로 감시배양 검사의 표준화를 통해 실효성 있는 감염관리체계에 이바지하고 감염관리 전문인력으로서의 전문성을 확보하고자 한다. 이를 통해 표준화 마련의 일차적인 목표는 의료관련 감염을 줄이고 국가적 의료관리 체계를 향상시키는데 있다. An essential measure to prevent healthcare-associated infections (HAI) is to develop a consistent system of surveillance, thereby promoting a reliable situation diagnosis to perform efficient control for the problem. Patient-to-patient transmission of pathogens within the hospital plays a substantial role in the epidemiology of HAIs. Contamination of healthcare environments commonly occurs, including facilities surfaces (e.g., bed rails, bedside tables), drinking water, cooling tower water, endoscopic instruments, food, airborne, endotoxin test, sterile test and medical equipment, with pathogenic organisms. In addition, epidemiological analysis is performed by multi locus sequence tying, pulsed-field gel electrophoresis for active surveillance. Therefore, an environmental surveillance culture test for prevention improves patient safety and blocks infection agents. Effective infection control and increased safety are possible by controlling the national infection control system. In conclusion, this study contributes to an effective infection control system through the standardization of active surveillance culture laboratory and secure expertise as infection control specialist. The primary objective of the standardization is to improve the safety of the nation’s healthcare system by reducing the rates of HAIs.