1.Minocycline Susceptibility of Carbapenem-Resistant Acinetobacter baumannii Blood Isolates from a Single Center in Korea: Role of tetB in Resistance
Taeeun KIM ; Eun Hee JEON ; Yoon-Kyoung HONG ; Jiwon JUNG ; Min Jae KIM ; Heungsup SUNG ; Mi-Na KIM ; Sung-Han KIM ; Sang-Ho CHOI ; Sang-Oh LEE ; Yang Soo KIM ; Yong Pil CHONG
Infection and Chemotherapy 2025;57(1):111-118
Background:
Carbapenem-resistant Acinetobacter baumannii (CRAB) represents a devastating and growing global threat, calling for new antibiotic treatments. In Korea, the challenge of treating CRAB is compounded by high nosocomial acquisition rates and limited availability of novel antibiotics. Minocycline, a semisynthetic tetracycline derivative, has been proposed as a therapeutic option for CRAB infections. Nonsusceptibility to minocycline may occur through the efflux pump, TetB. The prevalence of tetB in A. baumannii has increased, along with higher minocycline minimum inhibitory concentrations (MICs). We aimed to evaluate minocycline susceptibility rates in clinical strains of CRAB, and the association between tetB carriage and minocycline susceptibility across different genotypes.
Materials and Methods:
Representative CRAB blood isolates were collected from Asan Medical Center, Seoul.Minocycline susceptibility was assessed using the Clinical and Laboratory Standards Institute (CLSI) breakpoint (≤4 mg/L) and the proposed pharmacokinetics (PK)/pharmacodynamics (PD) breakpoint (≤1 mg/L). Tigecycline was used as a comparator, and its susceptibility breakpoint for Enterobacterales defined by EUCAST was applied (≤0.5 mg/L).The presence of tetB was detected by PCR, and multilocus sequence typing (MLST) was performed using seven housekeeping genes.
Results:
Of the 160 CRAB blood isolates, 83.8% were susceptible to minocycline by the CLSI criteria, and 50.6% were PK-PD susceptible by the PK-PD criteria. The minocycline minimum inhibitory concentration (MIC)50 /MIC90 was 1/8 mg/L. tetB was present in 49% of isolates and was associated with a higher minocycline MIC (MIC50/90 2/8 mg/L vs. 1/2 mg/L). No clear correlation was observed between tetB positivity and tigecycline MIC. Nine MLSTs were identified, with significant differences in tetB carriage rates between the major sequence types. Notably, ST191, associated with non-tetB carriage and greater susceptibility to minocycline, declined over the study period (P=0.004), while ST451, associated with tetB carriage, increased.
Conclusion
tetB was present in 49% of CRAB isolates and was associated with higher MICs and non-susceptibility by both CLSI and PK-PD criteria. However, absence of tetB was not a reliable predictor of minocycline PK-PD susceptibility. Additionally, shifts over time towards genotypes with reduced minocycline susceptibility were observed. Further research is needed to correlate these findings with clinical outcomes and identify additional resistance mechanisms.
2.Minocycline Susceptibility of Carbapenem-Resistant Acinetobacter baumannii Blood Isolates from a Single Center in Korea: Role of tetB in Resistance
Taeeun KIM ; Eun Hee JEON ; Yoon-Kyoung HONG ; Jiwon JUNG ; Min Jae KIM ; Heungsup SUNG ; Mi-Na KIM ; Sung-Han KIM ; Sang-Ho CHOI ; Sang-Oh LEE ; Yang Soo KIM ; Yong Pil CHONG
Infection and Chemotherapy 2025;57(1):111-118
Background:
Carbapenem-resistant Acinetobacter baumannii (CRAB) represents a devastating and growing global threat, calling for new antibiotic treatments. In Korea, the challenge of treating CRAB is compounded by high nosocomial acquisition rates and limited availability of novel antibiotics. Minocycline, a semisynthetic tetracycline derivative, has been proposed as a therapeutic option for CRAB infections. Nonsusceptibility to minocycline may occur through the efflux pump, TetB. The prevalence of tetB in A. baumannii has increased, along with higher minocycline minimum inhibitory concentrations (MICs). We aimed to evaluate minocycline susceptibility rates in clinical strains of CRAB, and the association between tetB carriage and minocycline susceptibility across different genotypes.
Materials and Methods:
Representative CRAB blood isolates were collected from Asan Medical Center, Seoul.Minocycline susceptibility was assessed using the Clinical and Laboratory Standards Institute (CLSI) breakpoint (≤4 mg/L) and the proposed pharmacokinetics (PK)/pharmacodynamics (PD) breakpoint (≤1 mg/L). Tigecycline was used as a comparator, and its susceptibility breakpoint for Enterobacterales defined by EUCAST was applied (≤0.5 mg/L).The presence of tetB was detected by PCR, and multilocus sequence typing (MLST) was performed using seven housekeeping genes.
Results:
Of the 160 CRAB blood isolates, 83.8% were susceptible to minocycline by the CLSI criteria, and 50.6% were PK-PD susceptible by the PK-PD criteria. The minocycline minimum inhibitory concentration (MIC)50 /MIC90 was 1/8 mg/L. tetB was present in 49% of isolates and was associated with a higher minocycline MIC (MIC50/90 2/8 mg/L vs. 1/2 mg/L). No clear correlation was observed between tetB positivity and tigecycline MIC. Nine MLSTs were identified, with significant differences in tetB carriage rates between the major sequence types. Notably, ST191, associated with non-tetB carriage and greater susceptibility to minocycline, declined over the study period (P=0.004), while ST451, associated with tetB carriage, increased.
Conclusion
tetB was present in 49% of CRAB isolates and was associated with higher MICs and non-susceptibility by both CLSI and PK-PD criteria. However, absence of tetB was not a reliable predictor of minocycline PK-PD susceptibility. Additionally, shifts over time towards genotypes with reduced minocycline susceptibility were observed. Further research is needed to correlate these findings with clinical outcomes and identify additional resistance mechanisms.
3.Minocycline Susceptibility of Carbapenem-Resistant Acinetobacter baumannii Blood Isolates from a Single Center in Korea: Role of tetB in Resistance
Taeeun KIM ; Eun Hee JEON ; Yoon-Kyoung HONG ; Jiwon JUNG ; Min Jae KIM ; Heungsup SUNG ; Mi-Na KIM ; Sung-Han KIM ; Sang-Ho CHOI ; Sang-Oh LEE ; Yang Soo KIM ; Yong Pil CHONG
Infection and Chemotherapy 2025;57(1):111-118
Background:
Carbapenem-resistant Acinetobacter baumannii (CRAB) represents a devastating and growing global threat, calling for new antibiotic treatments. In Korea, the challenge of treating CRAB is compounded by high nosocomial acquisition rates and limited availability of novel antibiotics. Minocycline, a semisynthetic tetracycline derivative, has been proposed as a therapeutic option for CRAB infections. Nonsusceptibility to minocycline may occur through the efflux pump, TetB. The prevalence of tetB in A. baumannii has increased, along with higher minocycline minimum inhibitory concentrations (MICs). We aimed to evaluate minocycline susceptibility rates in clinical strains of CRAB, and the association between tetB carriage and minocycline susceptibility across different genotypes.
Materials and Methods:
Representative CRAB blood isolates were collected from Asan Medical Center, Seoul.Minocycline susceptibility was assessed using the Clinical and Laboratory Standards Institute (CLSI) breakpoint (≤4 mg/L) and the proposed pharmacokinetics (PK)/pharmacodynamics (PD) breakpoint (≤1 mg/L). Tigecycline was used as a comparator, and its susceptibility breakpoint for Enterobacterales defined by EUCAST was applied (≤0.5 mg/L).The presence of tetB was detected by PCR, and multilocus sequence typing (MLST) was performed using seven housekeeping genes.
Results:
Of the 160 CRAB blood isolates, 83.8% were susceptible to minocycline by the CLSI criteria, and 50.6% were PK-PD susceptible by the PK-PD criteria. The minocycline minimum inhibitory concentration (MIC)50 /MIC90 was 1/8 mg/L. tetB was present in 49% of isolates and was associated with a higher minocycline MIC (MIC50/90 2/8 mg/L vs. 1/2 mg/L). No clear correlation was observed between tetB positivity and tigecycline MIC. Nine MLSTs were identified, with significant differences in tetB carriage rates between the major sequence types. Notably, ST191, associated with non-tetB carriage and greater susceptibility to minocycline, declined over the study period (P=0.004), while ST451, associated with tetB carriage, increased.
Conclusion
tetB was present in 49% of CRAB isolates and was associated with higher MICs and non-susceptibility by both CLSI and PK-PD criteria. However, absence of tetB was not a reliable predictor of minocycline PK-PD susceptibility. Additionally, shifts over time towards genotypes with reduced minocycline susceptibility were observed. Further research is needed to correlate these findings with clinical outcomes and identify additional resistance mechanisms.
4.Clinical Sensitivity of the (1–3)-β-D-glucan Test for Predicting Candidemia
Yun Woo LEE ; So Yun LIM ; Sol JIN ; Hye Jin PARK ; Heungsup SUNG ; Mi-Na KIM ; Seongman BAE ; Jiwon JUNG ; Min Jae KIM ; Sung-Han KIM ; Sang-Oh LEE ; Sang-Ho CHOI ; Yang Soo KIM ; Yong Pil CHONG
Annals of Laboratory Medicine 2023;43(4):381-385
The sensitivity of the (1–3)-β-D-glucan (BDG) diagnostic test for candidemia varies in different clinical settings, and its usefulness in early diagnosis of candidemia is suboptimal. We evaluated the sensitivity of the test for early candidemia prediction. All adult patients with culture-proven candidemia who underwent a serum Goldstream Fungus (1–3)-β-D-Glucan Test within seven days prior to candidemia onset at a tertiary referral hospital between January 2017 and May 2021 were included. Any-positive BDG results within seven days prior to candidemia onset were obtained in 38 out of 93 (40.9%) patients. The positive rate increased when the test was performed near the day of candidemia onset (P=0.04) but reached only 52% on the day of candidemia onset. We observed no significant differences between BDG-positive and -negative groups in terms of underlying disease, risk factors for candidemia, clinical presentation, origin of candidemia, and 30-day mortality. Candida albicans was significantly associated with positive BDG results than with all-negative BDG results (P=0.04). The Goldstream BDG test is unreliable for candidemia prediction because of its low sensitivity. Negative BDG results in patients with a high risk of invasive candidiasis should be interpreted with caution.
5.Medical Issues and Opinions of Obstetrics Regarding Abortion Law Amendment
Anna CHOI ; Yong Won PARK ; Sei Kwang KIM ; Seung Cheol KIM ; Pil Ryang LEE ; Kyoung Joo HWANG ; Jae Kwan LEE ; Kyung SEO ; Young Ju KIM ; Dong Hyun CHA ; Sunghun NA ; Dong Suk KIM ; Young Kyu LEE ; Youngseok WON ; Jae Yoo KIM ; Jaeyean KIM ; Jinhak KIM ; Woong JU ; Mi-Kyung KIM ; Jeong Yoel PARK
Journal of the Korean Society of Maternal and Child Health 2020;24(1):9-17
There have been ongoing social discussions on revision of the abortion law since the Constitutional Court ruled it nonconformity to the constitution on April 11, 2019. Thus, Korean Society of Obstetrics and Gynecology, Korean Society of Maternal Fetal Medicine, Korean College of Obstetricians and Gynecologists, and Korean Association of Obstetricians and Gynecologists organized 'special committee for abortion law' to support social discussion on the revision of the abortion law, and they prepared official opinions of obstetrics for medical issues including doctors' right to refuse abortion. In the future, the committee will continue to adapt to changes of medical environment especially after the revision of the abortion law by collecting its members' feedbacks.
6.Medical Issues and Opinions of Obstetrics Regarding Abortion Law Amendment
Anna CHOI ; Yong Won PARK ; Sei Kwang KIM ; Seung Cheol KIM ; Pil Ryang LEE ; Kyoung Joo HWANG ; Jae Kwan LEE ; Kyung SEO ; Young Ju KIM ; Dong Hyun CHA ; Sunghun NA ; Dong Suk KIM ; Young Kyu LEE ; Youngseok WON ; Jae Yoo KIM ; Jaeyean KIM ; Jinhak KIM ; Woong JU ; Mi-Kyung KIM ; Jeong Yoel PARK
Journal of the Korean Society of Maternal and Child Health 2020;24(1):9-17
There have been ongoing social discussions on revision of the abortion law since the Constitutional Court ruled it nonconformity to the constitution on April 11, 2019. Thus, Korean Society of Obstetrics and Gynecology, Korean Society of Maternal Fetal Medicine, Korean College of Obstetricians and Gynecologists, and Korean Association of Obstetricians and Gynecologists organized 'special committee for abortion law' to support social discussion on the revision of the abortion law, and they prepared official opinions of obstetrics for medical issues including doctors' right to refuse abortion. In the future, the committee will continue to adapt to changes of medical environment especially after the revision of the abortion law by collecting its members' feedbacks.
7.Differential diagnoses of magnetic resonance imaging for suspected acute appendicitis in pregnant patients
Jung Yong JI ; Na Ung JI ; Han Kuk SANG ; Choi Cho PIL ; LEE Hee JANG ; Shin Hyuk DONG
World Journal of Emergency Medicine 2018;9(1):26-32
BACKGROUND:Accurate and timely diagnosis of acute surgical disease in pregnant patient is chal enging. Although magnetic resonance imaging (MRI) is the most accurate modality to diagnose acute appendicitis in pregnant patients, it is often used as a last resort because of high cost and long scan time. We performed this study to analyze differential diagnoses of appendix MRI and to investigate if there are any blood tests that can predict surgical condition in pregnant patients. METHODS:A retrospective, cross-sectional study was conducted on 46 pregnant patients who underwent non-enhanced appendix MRI in suspicion of acute appendicitis from 2010 to 2016. Differential diagnoses of appendix MRI were analyzed and blood tests were compared between those who had surgical and non-surgical disease. RESULTS:Appendix MRI differentiated two surgical disease; acute appendicitis and ovarian torsion; and various non-surgical conditions such as uterine myoma, hydronephrosis, ureterolithiasis and diverticulitis among clinically suspected acute appendicitis in pregnancy. The diagnostic accuracy of MRI for acute appendicitis in this study was 93.5%. Patients who had surgical disease showed significantly higher WBC count (≥11,000/mm3), proportion of neutrophils in the WBC (≥79.9%), neutrophil-to-lymphocyte ratio (NLR≥6.4), levels of C-reactive protein (CRP≥1.82 mg/dL) and bilirubin (≥0.66 mg/dL ) than those who had non-surgical disease. CONCLUSION:MRI can reliably differentiate surgical conditions and several blood tests (WBC, proportion of neutrophils in the WBC, NLR, CRP, bilirubin) can help anticipate acute surgical condition among pregnant patients suspected to have acute appendicitis.
8.Impact of Revised Broad-Spectrum Cephalosporin Clinical and Laboratory Standards Institute Breakpoints on Susceptibility in Enterobacteriaceae producing AmpC β-Lactamase.
Ki Ho PARK ; Yong Pil CHONG ; Sung Han KIM ; Sang Oh LEE ; Mi Suk LEE ; Heungsup SUNG ; Mi Na KIM ; Yang Soo KIM ; Jun Hee WOO ; Sang Ho CHOI
Infection and Chemotherapy 2017;49(1):62-67
We evaluated the impact of revised Clinical and Laboratory Standards Institute (CLSI) breakpoints for broad-spectrum cephalosporins (BSCs) on the susceptibilities of 1,742 isolates of Enterobacter species, Serratia marcescens, Citrobacter freundii, and Morganella morganii. The 2011 CLSI criteria for cefotaxime and ceftazidime reduced the rates of susceptibility by 2.9% and 5.9%, respectively. The 2014 CLSI criteria for cefepime reduced the rate of susceptibility by 13.9%, and categorized 11.8% isolates as susceptible-dose dependent (SDD) for cefepime. Among 183 isolates with extended-spectrum ß-lactamase (ESBL) phenotype, implementation of the new criteria reduced the rates of susceptibility to cefotaxime, ceftazidime, and cefepime by 2.8%, 14.8%, and 53.6%, respectively. The proportion of ESBL phenotype among BSC-susceptible isolates was low (0.9% for cefotaxime, 3.0% for ceftazidime, and 3.3% for cefepime). In summary, implementation of new CLSI criteria led to little change in susceptibility to cefotaxime and ceftazidime but a substantial change in susceptibility to cefepime. The recognition of revised CLSI criteria for BSC and SDD will help clinicians to select the optimal antibiotic and dosing regimen.
Cefotaxime
;
Ceftazidime
;
Cephalosporins
;
Citrobacter freundii
;
Enterobacter
;
Enterobacteriaceae*
;
Morganella morganii
;
Phenotype
;
Serratia marcescens
9.Comparison of the GlideRite to the Conventional-malleable-stylet for Endotracheal Intubation by the Macintosh-laryngoscope: A Simulation Study Using Manekins.
Yong Tack KONG ; Hyun Jung LEE ; Ji Ung NA ; Dong Hyuk SHIN ; Sang Kuk HAN ; Jeong Hun LEE ; Pil Cho CHOI
Journal of the Korean Society of Emergency Medicine 2016;27(3):246-253
PURPOSE: The purpose of this study is to compare the effectiveness of the GlideRite with the conventional-malleable-stylet (CMS) in endotracheal intubation (ETI) using the Macintosh-laryngoscope. METHODS: This study is a randomized crossover simulation study. Participants performed ETI using both the GlideRite and the CMS in the normal airway and in a tongue edema (simulated difficult airway resulting in lower percentage of glottis opening [POGO]) model. RESULTS: In both the normal and the tongue edema models, all 36 participants performed ETI successfully using the two stylets on the first attempt. In the normal airway model, there was no difference in time required for ETI (T(ETI)) or ease of handling between the two stylets. In the tongue edema model, the T(ETI) increased as POGO score decreased with the CMS (POGO score showing negative correlation with T(ETI) for the CMS, Spearman's rho=-0.518, p=0.001) but not for the GlideRite (rho=-0.208, p=0.224). The T(ETI) was shorter with the GlideRite than the CMS, but without statistical significance (15.1 vs. 18.8 seconds, p=0.385). Ease of handling was superior with the GlideRite compared to the CMS (p=0.006). CONCLUSION: Performance of the GlideRite and the CMS was not different in the normal airway model. However, in the simulated difficult airway model with a low POGO score, the GlideRite performed better than the CMS for direct laryngoscopic intubation.
Edema
;
Glottis
;
Intubation
;
Intubation, Intratracheal*
;
Tongue
10.Comparison of the GlideRite to the conventional malleable stylet for endotracheal intubation by the Macintosh laryngoscope: a simulation study using manikins.
Yong Tack KONG ; Hyun Jung LEE ; Ji Ung NA ; Dong Hyuk SHIN ; Sang Kuk HAN ; Jeong Hun LEE ; Pil Cho CHOI
Clinical and Experimental Emergency Medicine 2016;3(1):9-15
OBJECTIVE: To compare the effectiveness of the GlideRite stylet with the conventional malleable stylet (CMS) in endotracheal intubation (ETI) by the Macintosh laryngoscope. METHODS: This study is a randomized, crossover, simulation study. Participants performed ETI using both the GlideRite stylet and the CMS in a normal airway model and a tongue edema model (simulated difficult airway resulting in lower percentage of glottic opening [POGO]). RESULTS: In both the normal and tongue edema models, all 36 participants successfully performed ETI with the two stylets on the first attempt. In the normal airway model, there was no difference in time required for ETI (TETI) or in ease of handling between the two stylets. In the tongue edema model, the TETI using the CMS increased as the POGO score decreased (POGO score was negatively correlated with TETI for the CMS, Spearman’s rho=-0.518, P=0.001); this difference was not seen with the GlideRite (rho=-0.208, P=0.224). The TETI was shorter with the GlideRite than with the CMS, however, this difference was not statistically significant (15.1 vs. 18.8 seconds, P=0.385). Ease of handling was superior with the GlideRite compared with the CMS (P=0.006). CONCLUSION: Performance of the GlideRite and the CMS were not different in the normal airway model. However, in the simulated difficult airway model with a low POGO score, the GlideRite performed better than the CMS for direct laryngoscopic intubation.
Edema
;
Intubation
;
Intubation, Intratracheal*
;
Laryngoscopes*
;
Manikins*
;
Tongue

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