• Journal of Food Hygiene and Safety
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• v.21 no.1
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• pp.23-30
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• 2006

Antimicrobial susceptibility and multiple drug resistance patterns have been carried out on total of 364 isolates of Salmonella enterica serovar Enteritidis isolated from foodborne patients in Seoul from 2001 to 2005. Overall, the highest percentage of resistance was found to the following antimicrobial agents: streptomycin (46.7%), ampicillin (37.3%), ticarcillin (36.7%), tetracycline (36.0%), nalidixic acid (20.7%), chloramphenicol (13.3%), amoxicillin/clavulanic acid (6.7%) and Ampicillin/sulbactam (4.0%). Seventy five percentage of isolates were found to be resistant to one or more of the antimicrobes tested. The resistant rates to nalidixic acid and chloramphenicol in S. Enteritidis tested were annually increased but the resistant rate to tetracycline was decreased and the resistant rates to streptomycin, ampcilin and ticarcillin were remained steadily. The most frequent patterns of multiresistant isolates were only nalidixic acid resistant (18.0%) and streptomycin-tetracycline (18.0%), streptomycin-ampicillin-ticarcillin (10%), and ampicillin-ticarcillin (5.5%). Overall the resistant rates of 1 drug was 19.3%,2 drugs 24.7%, 3 drugs 6.7% and 4 or more drugs 24.0%. The resistant rates of 1 drug and 2 drugs in 2005 were increased dramatically.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.2
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• pp.137-142
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• 2021

This study investigated the patterns of acquiring anti-mycobacterial resistance in individuals who were susceptible to all anti-mycobacterial drugs in their initial treatment. From 2010 to 2019, anti-mycobacterial drug susceptibility tests were conducted on patients who were referred to the Green Cross Laboratories. The test results of 594 anti-mycobacterial drug sensitivity tests were collected at 111 medical institutions. The first test results had 594 cases in which all anti-mycobacterial drugs were susceptible. Isoniazid (INH), rifampin (RIF), streptomycin (SM), and quinolone (QUI) showed the highest single-resistant conversion rates. Out of 56 patients, 17 patients (30.4%) showed a high conversion rate of resistance to both INH and RIF. The tracking period was analyzed from a minimum of 98 days to 1,862 days, and an average of 435.6 days for INH, and a minimum of 108 days to 1,673 days, with an average of 457.7 days for RIF. In the case of tuberculosis patients who are susceptible to all anti-mycobacterial drugs, it is considered that the conversion to resistant and multi-drug resistant tuberculosis (MDR-TB) must be confirmed through an anti-mycobacterial susceptibility test after 3 months. It is hoped that this study will help the national tuberculosis management project to improve public health.

• Archives of Pharmacal Research
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• v.19 no.5
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• pp.342-347
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• 1996

Doxorubicin, one of the clinically most useful anticancer agents, is used alone or in combination with other drugs against a wide variety of tumors, recently. But cancer cells developed resistance to this agent in many ways. This resistance is an important limiting factor of doxorubicin for anticancer drug. We newly established doxorubicin-resistant HCT15/CL02 subline from parental HCT15 human adenocarcinoma colon cancer cells. HCT15/CL02 revealed resistance to doxorubicin about 85-fold of its parental cells, and it also revealed cross-resistance to actinomycin D, etoposide and vinblastine but not to displatin and tamoxifen. And verapamil, a reversal agent of multidrug-resistance (MDR) by P-glycoprotein, elevated the cytotoxicity of doxorubicin against both HCT15 and GCT15/CL02 cells. But the relative resistant rate was not reduced. Verapamil had no effects on the tosicity of cisplatin to the both cell lines. These results indicate that HCT15/CL02 cells have some functionally complex mechanisms for MDR.

• Tuberculosis and Respiratory Diseases
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• v.79 no.4
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• pp.282-288
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• 2016

Background: Tuberculosis (TB) is a major health problem, and accurate and rapid diagnosis of multidrug-resistant (MDR) and extended drug-resistant (XDR) TB is important for appropriate treatment. In this study, performances of solid and liquid culture methods were compared with respect to MDR- and XDR-TB isolate recovery and drug susceptibility testing. Methods: Sputum specimens from 304 patients were stained with Ziehl-Neelsen method. Mycobacterium tuberculosis (Mtb) isolates were tested for recovery on $L{\ddot{o}wenstein$-Jensen (LJ) medium and the BacT Alert 3D system. For drug susceptibility testing of Mtb, isolates were evaluated on M-KIT plates and the BacT Alert 3D system. Results: The recovery rates were 94.9% (206/217) and 98.2% (213/217) for LJ medium and the BacT Alert 3D system, respectively (kappa coefficient, 0.884). The rate of drug resistance was 13.4% for at least one or more drugs, 6.0% for MDR-TB and 2.3% for XDR-TB. M-KIT plate and BacT 3D Alert 3D system were comparable in drug susceptibility testing for isoniazid (97.7%; kappa coefficient, 0.905) and rifampin (98.6%; kappa coefficient, 0.907). Antibiotic resistance was observed using M-KIT plates for 24 of the total 29 Mtb isolates (82.8%). Conclusion: The liquid culture system showed greater reduction in the culture period, as compared with LJ medium; however, drug susceptibility testing using M-KIT plates was advantageous for simultaneous testing against multiple drug targets.

• Tuberculosis and Respiratory Diseases
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• v.79 no.3
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• pp.158-164
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• 2016

Background: One to three percent of cases of acute tuberculosis (TB) require monitoring in the intensive care unit (ICU). The purpose of this study is to establish and determine the mortality rate and discuss the causes of high mortality in these cases, and to evaluate the clinical and laboratory findings of TB patients admitted to the pulmonary ICU. Methods: The data of patients admitted to the ICU of Yedikule Chest Diseases and Chest Surgery Education and Research Hospital due to active TB were retrospectively evaluated. Demographic characteristics, medical history, and clinical and laboratory findings were evaluated. Results: Thirty-five TB patients (27 males) with a median age of 47 years were included, of whom 20 died within 30 days (57%). The Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores were significantly higher, and albumin and $PaO_2/FIO_2$ levels were significantly lower, and shock, multiple organ failure, the need for invasive mechanical ventilation and drug resistance were more common in the patients who died. The mortality risk was 7.58 times higher in the patients requiring invasive mechanical ventilation. The SOFA score alone was a significant risk factor affecting survival. Conclusion: The survival rate is low in cases of tuberculosis treated in an ICU. The predictors of mortality include the requirement of invasive mechanical ventilation and multiple organ failure. Another factor specific to TB patients is the presence of drug resistance, which should be taken seriously in countries where there is a high incidence of the disease. Finding new variables that can be established with new prospective studies may help to decrease the high mortality rate.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.209-216
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• 2021

This study was aimed to investigate occurrence and the antimicrobial resistance of Escherichia coli isolates obtained from the feces of wild birds in Daegu. In total, 98 E. coli isolates (17.9%) were obtained from 547 fecal samples of wild birds. The E. coli carried by the birds showed a relatively high rate of antimicrobial resistance to tetracycline (27.6%) and ampicillin (21.4%). Drug resistance of the isolates to the others (penicillins, cephems, carbapenems, aminoglycosides, quinolones, sulfonamides and phenicols) resulted in the rates less than 20%, and all isolates were susceptible to imipenem, ciprofloxacin, cefotetan, and amikacin. Approximately, 45% E. coli among the isolates were resistant to one or more drugs tested. The higher rate of tetracycline resistance led us to determine the prevalence of the tet genes (tetA, tetB, tetC, tetD and tetE) in the tetracycline-resistant E. coli isolates by using PCR. All isolates of the tetracycline-resistant E. coli contained at least one or more of these tet genes examined. The most prevalent one was tetA (59.3%), and followed by tetB (7.4%) when tested with the selected 5 tet genes. Except tetA and tetB, however, the remaining tet genes (tetC, tetD, and tetE) tested were not found in this study. Nine isolates among the tetracycline-resistant E. coli contained the two (tetA and tetB) determinants of tetracycline resistance, simultaneously.

• Biomolecules & Therapeutics
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• v.30 no.4
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• pp.368-379
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• 2022

Hyaluronic acid (HA), a ligand of CD44, accumulates in some types of tumors and is responsible for tumor progression. The nuclear factor erythroid 2-like 2 (NRF2) regulates cytoprotective genes and drug transporters, which promotes therapy resistance in tumors. Previously, we showed that high levels of CD44 are associated with NRF2 activation in cancer stem like-cells. Herein, we demonstrate that HA production was increased in doxorubicin-resistant breast cancer MCF7 cells (MCF7-DR) via the upregulation of HA synthase-2 (HAS2). HA incubation increased NRF2, aldo-keto reductase 1C1 (AKR1C1), and multidrug resistance gene 1 (MDR1) levels. Silencing of HAS2 or CD44 suppressed NRF2 signaling in MCF7-DR, which was accompanied by increased doxorubicin sensitivity. The treatment with a HAS2 inhibitor, 4-methylumbelliferone (4-MU), decreased NRF2, AKR1C1, and MDR1 levels in MCF7-DR. Subsequently, 4-MU treatment inhibited sphere formation and doxorubicin resistance in MCF7-DR. The Cancer Genome Atlas (TCGA) data analysis across 32 types of tumors indicates the amplification of HAS2 gene is a common genetic alteration and is negatively correlated with the overall survival rate. In addition, high HAS2 mRNA levels are associated with increased NRF2 signaling and poor clinical outcome in breast cancer patients. Collectively, these indicate that HAS2 elevation contributes to chemoresistance and sphere formation capacity of drug-resistant MCF7 cells by activating CD44/NRF2 signaling, suggesting a potential benefit of HAS2 inhibition.

• Clinical and Experimental Pediatrics
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• v.60 no.5
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• pp.151-157
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• 2017

Purpose: Macrolide resistance rate of Mycoplasma pneumoniae has rapidly increased in children. Studies on the clinical features between macrolide susceptible-M. pneumoniae (MSMP) and macrolide resistant-M. pneumoniae (MRMP) are lacking. The aim of this study was to identify the macrolide resistance rate of M. pneumoniae in Korean children with M. pneumoniae penupmonia in 2015 and compare manifestations between MSMP and MRMP. Methods: Among 122 children (0-18 years old) diagnosed with M. pneumoniae pneumonia, 95 children with the results of macrolide sensitivity test were included in this study. Clinical manifestations were acquired using retrospective medical records. Results: The macrolide resistant rate of M. pneumoniae was 87.2% (82 of 94 patients) in children with M. pneumoniae pneumonia. One patient showed a mixed type of wild type and A2063G mutation in 23S rRNA of M. pneumoniae. There were no significant differences in clinical, laboratory, and radiologic findings between the MSMP and MRMP groups at the first visit to our hospital. The time interval between initiation of macrolide and defervescence was significantly longer in the MRMP group ($4.9{\pm}3.3$ vs. $2.8{\pm}3.1days$, P=0.039). Conclusion: The macrolide resistant rate of M. pneumoniae is very high in children with M. pneumoniae pneumonia in Korea. The clinical manifestations of MRMP are similar to MSMP except for the defervescence period after administration of macrolide. Continuous monitoring of the occurrence and antimicrobial susceptibility of MRMP is required to control its spread and establish strategies for treating second-line antibiotic resistant M. pneumoniae infection.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.1
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• pp.9-17
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• 1997

Resistance to combination chemotherapy remains challenge in the treatment of osteosarcoma. One of the mechanisms of multiple drug resistance is an increased expression of the multidrug resistance gene(mdr1). Expression of the P-glycoprotein(mdr-1 gene product) was studied immunohistochemically and the mdr-1 gene by in situ hybridization in 33 osteosarcomas relating to various prognostic factors. Thirty cases out of 33 osteosarcomas(90.9%) showed positive cytoplasmic reactions with P-glycoprotein and nineteen instances(57.6%) were strong positive(2+). The older(>20 years) and female patients revealed more intense immunohistochemical reactions rather than those of the younger and male patients. Osteoblastic and chondroblastic osteosarcomas revealed more strong immunohistochemical reactions compared to fibroblastic types. There were no significant staining differences between the type of bony involvement, Broder's grade and the presence of necrosis. On follow-up, the mean survival rate was decreased in the strong positive group, however, this was not statistically significant. In situ hybridization for mdr-1 gene revealed positive signals in 22 cases out of 29 osteosarcomas(75.9%). Chemotherapy was done in 15 cases out of 28 patients(53.6%). The results of immunohistochemistry and in situ hybridization were not correlated with the protocols for chemotherapy. However, this result should be confirmed by a larger scale study about mdr1 mRNA expression.

• Tuberculosis and Respiratory Diseases
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• v.80 no.2
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• pp.143-152
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• 2017

Background: Fluoroquinolones are considered important substitutes for the treatment of tuberculosis. This study investigates the current status of fluoroquinolone for the treatment of tuberculosis. Methods: In 2009, a retrospective analysis was performed at one tertiary referral center for 953 patients diagnosed with tuberculosis. Results: A total of 226 patients (23.6%), who received fluoroquinolone at any time during treatment for tuberculosis, were enrolled in this study. The most common reasons for fluoroquinolone use were adverse events due to other anti-tuberculosis drugs (52.7%), drug resistance (23.5%), and underlying diseases (16.8%). Moxifloxacin (54.0%, 122/226) was the most commonly administered fluoroquinolone, followed by levofloxacin (36.3%, 82/226) and ofloxacin (9.7%, 22/226). The frequency of total adverse events from fluoroquinolone-containing anti-tuberculosis medication was 22.6%, whereas fluoroquinolone-related adverse events were estimated to be 2.2% (5/226). The most common fluoroquinolone-related adverse events were gastrointestinal problems (3.5%, 8/226). There were no significant differences in the treatment success rate between the fluoroquinolone and fluoroquinolone-$na{\ddot{i}}ve$ groups (78.3% vs. 78.4%, respectively). Conclusion: At our institution, fluoroquinolones are commonly used for the treatment of both multidrug-resistant tuberculosis and susceptible tuberculosis, especially as a substitute for adverse event-related drugs. Considering the low adverse event rates and the comparable treatment success rates, fluoroquinolones seem to be an invaluable drug for the treatment of tuberculosis.