• Korean Journal of Clinical Laboratory Science
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• v.54 no.2
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• pp.125-132
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• 2022

The prevalence of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) are increasing. We analyzed the patterns of drug resistance and tracking period days of acquiring anti-mycobacterial resistance. From January 2010 to December 2019, drug susceptibility tests (DST) were performed by the absolute concentration method using the Löwenstein-Jensen solid medium and pyrazinamidase activity test (to assess pyrazinamide resistance) in samples from patients who were referred to the Green Cross Laboratories in Yongin. Among the cases that showed resistance to one or more anti-tuberculosis drugs, 55 patients (33.1%) were resistant to isoniazid (INH) at the time of initial referral, and the rates for the development of resistant anti-tuberculosis drugs were ethambutol (EMB) (26.6%), rifampicin (RFP) (21.9%), quinolones (QUI) (21.9%) and pyrazinamide (PZA) (10.9%), in that order. In the cases sensitive to all 10 anti-tuberculosis drugs initially, the development of resistance to INH was the most frequent, seen in 43 patients (7.2%). The average follow-up period was 435.6 days, and the resistance development was observed in the order of INH (7.2%), RFP (3.9%), SM (1.9%), QUI (0.7%), amikacin (AMK) (0.5%), and EMB (0.5%). The conversion of susceptible strains to resistant strains is an important warning sign for the patient, especially in cases of conversion to MDR or XDR. This information would be helpful for improving patient care during TB treatment.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.265-272
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• 2022

The emergence and dissemination of carbapenemase-producing Enterobacteriaceae (CPE), particularly the Klebsiella pneumoniae carbapenemase-2 (KPC-2) producing Klebsiella pneumoniae, has been rapidly increasing worldwide and is becoming a serious public health threat. Since the epidemiology and characteristics of these KPC-2-producing K. pneumoniae vary according to the region and period under consideration, this study investigated the prevalence of carbapenemases and the epidemiological relationship of 78 carbapenem-resistant K. pneumoniae (CRKP) isolated from a tertiary hospital in Daejeon, from March 2017 to December 2020. The antimicrobial susceptibility tests were identified using the disk-diffusion method. PCR and DNA sequencing were used to determine the carbapenemase genes. In addition, molecular epidemiology was performed by multilocus sequence typing (MLST). Among the 78 CRKP isolates, 35 isolates (44.9%) were carbapenemase-producing K. pneumoniae (CPKP) and the major carbapenemase type was KPC-2 (30 isolates, 85.7%). The New Delhi metallo-enzyme-1 (NDM-1) and NDM-5 were identified in 4 isolates (11.4%) and 1 isolate (2.9%), respectively. Multilocus sequence typing (MLST) analysis showed 10 sequence types (STs) and the most prevalent ST was ST307 (51.4%, 18/35). All the ST307 isolates were KPC-2-producing K. pneumoniae and were multidrug-resistant (MDR). In addition, ST307 has gradually emerged during a four-year period. These findings indicate that continuous monitoring and proper infection control are needed to prevent the spread of KPC-2-producing K. pneumoniae ST307.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.1
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• pp.23-27
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• 2022

Disposable wet wipes provided by general restaurants in the Jeju Special Self-Governing Province were evaluated for compliance with the labeling requirements and the degree of bacterial contamination set by the Ministry of Food and Drug Safety. Of the 32 types of disposable wipes, five types of disposable wipes did not indicate the name and location of the business office of the manufacturer. Only 12 types of wet wipes were marked with the date of manufacture and expiration date. Bacterial contamination was seen in 9 types of wet wipes through bacterial culture but these were absent in the remaining 23 types (71.9%). The results of the antimicrobial susceptibility test for the 9 identified strains showed no methicillin-resistant coagulase-negative staphylococci (MRCNS) or multidrug-resistant bacteria. Through this study, it is recommended that the date of manufacture and expiration date must be indicated on the surface of disposable wet wipes designated as hygiene products, and clean uncontaminated wet wipes must comply with storage standards. In addition, the results are expected to contribute to the enhancement and improvement of hygiene management supervision, personal hygiene management, and an improvement in national health.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.227-239
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• 2022

Purpose: In our study, in order to find lactic acid bacteria (LAB) with multi-drug resistance to antibiotics, we isolated 140 strains from 15 types of kimchi commercially available in Korea and 20 types of Kimchi made at home from January to December in 2016, and investigated their H₂O₂ generating ability and multi-drug resistance to antibiotics. Methods: In order to observe the H₂O₂ generation ability of LAB, we performed the experiment with methods such as Rabe, Hillier, and Kang. To test the antibacterial susceptibility of LAB, we used the disc agar diffusion method using MRS agar (Difco, USA) according to the CLSI and WHO test methods. There are 18 types of antibiotic discs used. Results: Out of the total numbers of 140 strains, 6 strains of Ent. Faecium, 25 strains of L. plantarum, 1 strain of L. rhamnosus, 3 strains of L. sakei, 1 strain of L. acidophilus, 1 strains St. thermophilus, and 7 of unidentified strains generated H₂O₂. The antibiotic susceptibility of Ent. Faecium indicated SXT, OX, NA, and E; and the antibiotic susceptibility of L. plantarum indicated NA; and the antibiotic susceptibility of St. thermophilus indicated NA, CC, RA, CTT, CM, and P ; and the antibiotic susceptibility of L. rhamnosus indicated SXT, VA, NA and CTT; and the antibiotic susceptibility of 6 strains of L. sakei indicated SXT, OX, NOR, NA, CTT and CIP, all indicating antibiotic resistance. In the case of multi-drug resistance to antibiotics for 53 strains of L. antarum, 8-drug resistance was the most common with 25 strains, followed by 7-drug-resistant strains with 18 strains, 9-drug-resistant strains with 4 strains, 6-drug-resistant strains with 3 strains, 5-drug-resistant strains with 2 strains, and 17-drug-resistant strains with 1 strain. In the case of multi-drug resistance to antibiotics for Ent. Faecium 27 strains, 9-drug resistance was most commonly identified as 9 strains, 8-drug resistance was identified as 6 strains, 7- and 11 drug resistances were identified as 4 strains each, and 4- and 6-drug resistances were identified as 1 strain each. Conclusion: Ent. Faecium, L. plantarum, L. rhamnosus, L. sakei, and St. thermophilus, shown to have anantibacterial activity in previous studies on LAB and shown to have and H₂O₂ generating ability, antibiotic resistance and multi-drug resistance in this study, are expected to be able to play an excellent role for long-term inpatients to use as an alternative to antibiotics and to cope with emerging antibiotic resistance.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.134-151
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• 2024

Salmonella spp. is among the most important water-borne and food-borne pathogens and is one of the most common causes of human gastroenteritis and diarrheal diseases globally. In this study, Salmonella spp. isolated from food, environmental samples, and patients with food poisoning or diarrhea were investigated Salmonella serovars, antibiotic resistance using Vitek2, and genetic characteristics through pulsed-field gel electrophoresis (PFGE). Salmonella spp. of 339 strains, including 26 strains from food or environmental samples and 313 strains from patients, were isolated from Jeju Island of South Korea between 2020 and 2023. The monthly number of isolated Salmonella spp. gradually increased from March, with the highest number being in August. No significant differences in Salmonella spp. isolated from patients according to gender was observed. However, Salmonella spp. was most frequently isolated from people aged 70 years or older and least frequently isolated from those between ages 10 and 19 years. Salmonella spp. isolated from food or environmental samples were distributed among eight different serovars and the main serovars were identified in the order of S. Bareilly (26.9%), S. Rissen (23.1%), and S. Thompson (19.3%). Salmonella spp. isolated from patients were distributed among 27 different serovars and the main serovars were identified in the order of S. Bareilly (31.0%), S. Typhimurium (24.6%), and S. Enteritidis (11.5%). The main cause serovars of Salmonella spp. outbreaks are S. Bareilly, S. Enteritidis, S. Thompson. Antibiotic resistance tests indicated resistance to various antibiotics and some Salmonella spp. exhibited multidrug resistance. Salmonella spp. showed various genetic correlations among the 17 serovars. These results indicate that they can be used as basic data for epidemiological investigations by predicting the appearance of Salmonella spp. and providing a scientific basis.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.500-506
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• 2023

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is emerging as a worldwide public health threat. Recently, Klebsiella pneumoniae carbapenemase-2 (KPC-2)-producing sequence type (ST) 307 was identified main clone of CRKP, and dissemination of ST307 was reported in South Korea. This study examined the molecular characteristic and antimicrobial resistance pattern of 50 CRKP isolated from a tertiary hospital in Daejeon, from March 2020 to December 2021. Epidemiological relationship was analyzed by Multilocus sequence typing (MLST) and antimicrobial susceptibility test was determined using disk-diffusion method. PCR and DNA sequence analysis were performed to identify carbapenemase genes. CRKP infections were significantly more frequent in males and the patients aged ≥ 60 years. Among the 50 CRKP isolates, 46 isolates (92.0%) were multidrug-resistant (MDR), and 44 isolates (88.0%) were carbapenemase-producing K. pneumoniae (CPKP). The major carbapenemase type was KPC-2 (36 isolates, 72.0%) and New Delhi metalloenzyme-1 (NDM-1) and NDM-5 were identified in 7 isolates (14.0%) and 1 isolate (2.0%), respectively. In particular, 88.9% (32/36) of KPC-2-producing K. pneumoniae belonged to ST307, whereas 87.5% (7/8) of NDM-1,-5-producing K. pneumoniae belonged to non-ST307. These results suggest that proper infection control and effective surveillance network need to prevent not olny the spread of ST307, but also the development of non-ST307.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.181-190
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• 2024

Bovine mastitis-associated Escherichia coli (BMEC) is considered the main causative agent of significant financial losses in the dairy industry worldwide, as it alters both the quantity and quality of milk produced and increases the rate of culling. This creates a variety of challenges for researchers, veterinarians, and farmers in understanding and determining the most effective therapies and diagnostic techniques. Subclinical mastitis is particularly concerning, as infected bovines exhibit no obvious symptoms and continue to secrete apparently normal milk over an extended period, allowing the causative pathogen, E. coli, to spread within the herd. For effective prevention, understanding the pathogenesis of mastitis through three stages invasion, infection, and inflammation is essential. To date, no clear correlation has been found between virulence factors and pathogenicity contributing to the clinical severity of BMEC. Multidrug-resistant E. coli and the evolution of novel resistance mechanisms have become concerns owing to the extensive use of antibiotics to treat mastitis. Therefore, it is vital to explore alternative controls to enhance the efficacy of BMEC treatment. Over the past 30 years, various genetic typing techniques have been used to examine the subspecies-level epidemiology of bovine mastitis. These studies have advanced our understanding of the origin, transmission pathway, population structure, and evolutionary relatedness of BMEC strains. In this review we provide an overview of BMEC, including insights into its etiology, genetic relationship, pathogenesis, and management of the disease, as well as new therapy options.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.156-162
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• 2008

Salmonellosis is a major bacterial zoonosis that causes a variety of disease syndromes, self-limited enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. Recently, the emergence of multidrug resistant strains of Salmonella spp. causes more serious problems in environment and public health. The present study was investigated the antibacterial effect of Houttuynia cordata ethanol extract(HCEE) for murine salmonellosis. In the cytotoxic effect of HCEE on RAW 264.7 cells, there was no detectable effect with any concentrations between 25 and 100 ${\mu}g/ml$ after 8 h incubation. The bacteriocidal effect of HCEE was not showed on a Salmonella enterica serovar Typhimurium(S. typhimurium). HCEE makes morphological change of the RAW 264.7 cells, and there was significant decreased bacterial uptake and intracellular replication within Salmonella infected cells. And further nitric oxide(NO) production of Salmonella infected RAW 264.7 cells with HCEE was decreased comparing to RAW 264.7 cells without HCEE until 8 h post infection. Oral administration of HCEE showed a therapeutic effect for S. typhimurium infected BALB/c mice. The mortality of HCEE treated mouse was 80% until 12 days, while that of HCEE untreated mouse was 100 % until 8 days after lethal dose of S. typhimurium infection. These data suggested that HCEE has a potency treatment for intracellular replicative pathogen including salmonellosis, brucellosis, tuberculosis, listeriosis etc., and the application of HCEE makes new strategies for safety medicine development without antibiotic resistance bacterial appearance and residue problem in food and solves the public health problem from antibiotic mis- and over use.

• Clinical and Experimental Pediatrics
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• v.52 no.7
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• pp.791-797
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• 2009

Purpose : We aimed to investigate the clinical manifestations of and antibiotic resistance in culture-proven childhood salmonellosis. Methods : Clinical manifestations and laboratory data of and antibiotic use in subjects with culture-proven childhood salmonellosis, who were treated at the Chonbuk National University Hospital between September 1998 and August 2008, were analyzed retrospectively. Patients with underlying diseases or concomitant illnesses were excluded. Results : We assessed a total of 72 patients. There were 68 stool culture-positive cases, 7 blood culture-positive cases, and 3 both stool culture- and blood culture-positive cases. Salmonella group D was the most frequent pathogen in stool (63.9%) and blood (71.4%) cultures. Salmonella typhi was isolated in 1 case. Of the 72 patients, 45 (62.5%) were male children, of which 29 (40.3%) were aged <3 years. The patients most commonly presented with diarrhea (90.2%) and fever (83.3%). Leukocytosis (leukocyte count, >$15,000/{\mu}L$) and leukopenia (leukocyte count, <$4,000/{\mu}L$) were detected in 8.3% and 5.6% of the patients, respectively. Elevated serum C-reactive protein concentration (>5 mg/dL) and erythrocyte sedimentation rate (>20 mm/h) were observed in 88.9% and 58.3% of the patients, respectively. Fifty-two (85.2%) of 61 patients who had undergone antibiotic treatment received a third-generation cephalosporin as definitive antibiotic therapy. Multidrug resistance rate was 40.0 % in the first 5 years of the study and 71.4% in the last 5 years. No fatalities occurred in this series. Conclusion : Children with culture-proven salmonellosis showed relatively benign clinical outcomes. Appropriate antibiotic treatment of <2 weeks is probably adequate for those without a suppurative focus of infection. The incidence of antibiotic resistant isolates was recently seen to increase.

• Tuberculosis and Respiratory Diseases
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• v.42 no.1
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• pp.11-18
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• 1995

Background: The natural history of bacillary tuberculosis was studied in India and results showed that at the end of the 5-year period, 49% of the patients were dead, 33% were cured and 18% remained sputum-positive. The aim of this survey is to observe the natural course of the patients with intractable tuberculosis disease who were incurable with all drug regimens of the national tuberculosis programme(NTP). Method: Of the patients who have been found as intractable cases in Kang-Weon Province by the supervisory medical officer during the period from January 1,1987 to December 31,1992, 179 were eligible for this study. Sputum examination was done for those who were survived until October in 1993 at the Kang-Weon provincial laboratory of KNTA. 49 out of 179 patients were transferred to the private sectors and retreated with the combination of prothionamide, cycloserine, ofloxacin, enviomycin, etc. They seemed to have been bacteriologically cured, and so they were excluded from the study. Finally 130 patients were analyzed by modified life table method to calculate the fatality rate and the survival rate during the period of 7 years. Results: 1) 80.8% of intractable cases were male and 19.2%, female. 2) More than 94% of intractable cases showed moderately or far advanced Tb findings on their X-rays at the time of registration at health centres. 3) The cumulative case-fatality rate was 19.74% at the end of 1-year period and has risen to 34.55% by the end of 4-year period(increasing by 4.9% a year on an average). The case-fatality rate has shown no appreciable rise since then until the end of 7-year period. 4) The case-survival rate was 80.26% at the end of 1-year period and has decreased to 65.45% by the end of 4-year period. And then there was no appreciable change in the survival rate until the end of 7-year observation. Conclusion: The case-survival rate of intractable cases was higher than that of untreated pulmonary tuberculosis patients and they may have risk of spreading multidrug resistant organisms. It is time we made an effort to improve case-management qualitatively.