• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.394-401
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• 2016

Recently, the clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR/Cas9) system, a genome editing technology, was shown to be versatile in treating several antibiotic-resistant bacteria. In the present study, we applied the CRISPR/Cas9 technology to kill extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. ESBL bacteria are mostly multidrug resistant (MDR), and have plasmid-mediated antibiotic resistance genes that can be easily transferred to other members of the bacterial community by horizontal gene transfer. To restore sensitivity to antibiotics in these bacteria, we searched for a CRISPR/Cas9 target sequence that was conserved among >1,000 ESBL mutants. There was only one target sequence for each TEM- and SHV-type ESBL, with each of these sequences found in ~200 ESBL strains of each type. Furthermore, we showed that these target sequences can be exploited to re-sensitize MDR cells in which resistance is mediated by genes that are not the target of the CRISPR/Cas9 system, but by genes that are present on the same plasmid as target genes. We believe our Re-Sensitization to Antibiotics from Resistance (ReSAFR) technology, which enhances the practical value of the CRISPR/Cas9 system, will be an effective method of treatment against plasmid-carrying MDR bacteria.

• Natural Product Sciences
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• v.17 no.4
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• pp.296-302
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• 2011

We determined the inhibitory activity of the essential oil fraction obtained by steam distillation from the fresh and dried leaves of Perilla frutescens var. acuta against some pathogenic Salmonella and Vibrio spp. The activities of compounds isolated from the essential oils, apiol and myristicin, were also tested and the results were compared with those of the essential oil fraction. The Perilla essential oil fraction and its main components showed significant inhibition against antibiotic-susceptive and antibiotic-resistant strains of the tested Salmonella and Vibrio strains. Synergistic or additive effects were identified by combing the oils with ampicillin by checkerboard-titer tests. We conclude that essential oils from P. frutescens can be useful in the treatment of Salmonella and Vibrio infections and as safe additives to food materials for the prevention of contamination of food by these bacteria. This is especially important because of the rapid increase in antibiotic-resistant strains, which could cause severe symptoms in humans.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.797-803
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• 2013

Recently, a number of countries are now considering the reuse of effluents from wastewater treatment for various water applications. To improve the reuse of wastewater effluent, the development of appropriate micro-pollutant removal technology is necessary. Although several researche have been studied for removing micro-pollutants in water, little study has been conducted for the removal of emerging contaminant such as antibiotic resistant genes (ARGs) by disinfection processes. Therefore, the aim of this study is to compare the capacity of disinfection technologies such as chlorination, ozone, and electron beam, for removing antibiotic resistant bacteria (ARB) and ARGs. Based on this study, better ARG removal can be achieved by ozonation and electron beam. Relatively, high CT values of chlorination or ozonation are needed to remove ARB and ARG compared to conventional pathogens.

• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.1
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• pp.103-111
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• 2021

The purpose of this study is to investigate the antibacterial efficacy of cotton and silk/rayon fabrics dyed with Saururus chinensis extract against antibiotic-resistant strains. The concentration of the concentrated dye in the Saururus chinensis extracts was 1.1% (o.w.f), and the liquor ratio was 1:10 at 30-70℃. The mordanting method was a post mordanting method. The concentration of Al2(SO4)3, CuSO4 5H2O and FeSO4 and7H2O mordant was 5% (o.w.f), and the liquor ratio was 1:40. In order to assess the antimicrobial activity of naturally dyed fabrics, Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 33591, was used by incubating it in Brain Heart Infusion Agar (BHA) including Oxacillin (2㎍/ml) and Fungizone (2.5㎍/ml) and Brain Heart Infusion broth (BHI; Detroit, MI, USA.) The investigation of the reduction of the rate of antibiotic-resistant strains to dyed cotton fabrics and silk/rayon fabrics revealed that Cu mordanting fabric has the highest antimicrobial effects, with the rate of 99.7%, and Fe mordanting fabric has the lowest, with 77.7%. Non-mordant cotton fabrics also show a high reduction rate of strains (94.6%). In the case of dyed silk/rayon fabrics, it indicates a high reduction in the rate of strains in all fabrics with non-mordant treatment (94.2%), Al mordanting (99.6%), and Cu and Fe mordanting(99.9%).

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.252-256
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• 2005

The in visto inhibitory activities of essential oils of the Rosmarinus officinalis as well as its main constituents were evaluated against antibiotic-susceptible and -resistant strains of Staphylococcus aureus, streptococcus pneumoniae, Salmonella enteritidis and S. typhimurium. The essential oil fraction of R. officinalis and its main components, 1,8-cineole and camphor, exhibited significant inhibitory activities against most of the tested strains in this study, with MICs(minimum inhibitory concentrations) racing from 0.5mg/ml to 16mg/ml. The total oil fraction showed higher activity than its main components, 1,8-cineole and camphor against S. aureus strains. No remarkable differences were evident between MICs of the susceptible and resistant strains of S. aureus. Among the tested strains, S. pneumoniae CCARM 3523, the resistant strain to norfloxacin, oxacillin and erythromycin exhibited significantly lower sensitivity to the tested oils than antibiotic-susceptible strain. The oils revealed mostly higher inhibitory activity against S. typhimurium than against S. enteritidis.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.204-207
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• 2009

We investigated novel antibacterial and synergistic activities of isocryptomerin isolated from Selaginella tamariscina. Isocryptomerin showed potent antibacterial activity against Gram-positive and Gram-negative bacterial strains including clinical isolates of antibiotic-resistant species such as methicillin-resistant Staphylococcus aureus(MRSA). Additionally, we further investigated the synergistic activity of isocryptomerin with a conventional antibiotic against MRSA. The result indicated that isocryptomerin had considerable synergistic activity in combination with cefotaxime. In summary, the present study suggests that isocryptomerin may have potential as a novel therapeutic agent for treatment of infectious diseases by not only human pathogenic bacteria but also multidrug-resistant bacteria.

• Journal of Microbiology and Biotechnology
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• v.33 no.3
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• pp.277-287
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• 2023

Since the first discovery of antibiotics, introduction of new antibiotics has been coupled with the occurrence of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Rapid dissemination of ARB and ARGs in the aquatic environments has become a global concern. ARB and ARGs have been already disseminated in the aquatic environments via various routes. Main hosts of most of ARGs were found to belong to Gammaproteobacteria class, including clinically important potential pathogens. Transmission of ARGs also occurs by horizontal gene transfer (HGT) mechanisms between bacterial strains in the aquatic environments, resulting in ubiquity of ARGs. Thus, a few of ARGs and MGEs (e.g., strA, sul1, int1) have been suggested as indicators for global comparability of contamination level in the aquatic environments. With ARB and ARGs contamination, the occurrence of critical pathogens has been globally issued due to their widespread in the aquatic environments. Thus, active surveillance systems have been launched worldwide. In this review, we described advancement of methodologies for ARGs detection, and occurrence of ARB and ARGs and their dissemination in the aquatic environments. Even though numerous studies have been conducted for ARB and ARGs, there is still no clear strategy to tackle antibiotic resistance (AR) in the aquatic environments. At least, for consistent surveillance, a strict framework should be established for further research in the aquatic environments.

• 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.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.409-413
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• 2014

BACKGROUND: Large amount of veterinary antibiotics have been used in the livestock industry to prevent diseases and promote growth. These antibiotics are excreted through feces and urine in unchanged form and reach to agricultural fields via application of the livestock manure based composts. The purpose of this study was to evaluate the occurrence of tetracyclines-resistant bacteria in the soil received livestock manure compost for a long term. METHODS AND RESULTS: Tetracyclines (tetracycline TC, chlortetracycline CTC, and oxytetracycline OTC) resistance bacteria in the soil of rice-onion field applied pig manure compost (PM), in the soil of grass-rye field received cow manure compost (CM), and in the soil of rice field applied inorganic fertilizer (NPK) were determined. The soil received livestock manure composts clearly showed higher number of TC, CTC, and OTC resistance bacteria compared with the soil treated with inorganic fertilizer. The antibiotic resistant bacteria recovered appeared at 80 mg/L of tetracyclines was identified 1 specie, 6 genera 7 species, and 6 genera 7species in the soils received CM, PM, and NPK, respectively. The dominant resistant bacteria with the CM and PM application were Ochrobactrum and Rhodococcus. CONCLUSION: The application of livestock manure compost in the agricultural field is likely to contribute the occurrence of antibiotic resistance bacteria in the agricultural environment.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.414-422
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• 2001

Antibiotic resistance in human pathogens is a major public health issue. Some of the resistance problem can be attributed to the transfer of resistant bacteria from animals to people and the transfer of resistance genes from animal pathogens and commensal bacteria to human pathogens. Control measures include improvements in food hygiene to reduce the spread of zoonotic bacteria to people via the food chain. However, to specifically address the issue, the medical profession must control misuse and overuse of antibiotics in hospitals and community practice. In addition, the livestock industries and their advisors must reduce and refine the use of antibiotics in animal production and replace antibiotics with alternative disease control measures as much as possible.