• Journal of Microbiology
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• v.45 no.4
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• pp.350-357
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• 2007

This study was conducted in an effort to evaluate the antimicrobial activity and antibiotic-resistant gene regulation from Saliva miltiorrhiza Bunge on methicillin-resistant Staphylococcus aureus (MRSA). A variety of solvent fractions and methanol extracts of S. miltiorrhiza Bunge were tested in order to determine its antimicrobial activities against S. aureus and MRSA. As a result, the hexane fraction of S. miltiorrhiza Bunge evidenced the highest levels of antimicrobial activity against S. aureus and MRSA. The MICs of the hexane fraction against various MRSA specimens were $64. The hexane fraction evidenced inhibitory effects superior to those of the chloroform fraction. The results showed inhibition zones of hexane (16 mm) and chloroform (14 mm) fractions against MRSA KCCM 40511 at $1,000{\mu}g/disc$. The hexane and chloroform fractions inhibited the expression of the resistant genes, mecA, mecR1, and femA in mRNA. Moreover, the results of Western blotting assays indicated that the hexane and chloroform fractions inhibited the expression of the resistant protein, PBP2a. These results reveal that the hexane and chloroform fractions of S. miltiorrhiza Bunge may prove to be a valuable choice for studies targeted toward the development of new antimicrobial agents.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.2
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• pp.181-188
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• 1992

This study was carried out to evaluate the fate of inoculant Bradyrhizobium japonicum and the inoculation effect on soybean in complex soil environment. To moniter Rhizobium strains from the root, streptomycine and streptomycine and nalidixic acid resistant marker strains were prepared by spontaneous mutagenesis. The characteristics and properties of antibiotic marked strains were not altered by the mutagenesis. The comparison of properties of wild type and antibiotic resistant Bradyrhizobium strains are summarized as follow : 1) The strains of USDA110K-$STR^r$, USDA110N-$STR^r$ and R318-$STR^r$ showed weak tolerance to pH 9.0. The utilization of carbon sources by fast growing group was different from that of slow growing group. The marked strains of R214-$STR^rNAL^r$, USDA110K-$STR^r$ and USDA110N-$STR^r$ was doubtful in utilization of sorbitol and R138-$STR^rNAL^r$ was doubtful in utilization of xylose as a carbon source. 2) By examining the agglutination reaction of serogroups, the strains used were identified as different ones. There were no differences between wild type and marked strains in agglutination titer values. 3) The plasmid size of fast group was slightly greater than that of slow group. However, there was no differences in plasmid size between the wild type and antibiotic resistant strains. This result indicates that the antibiotic resistance was not encoded in plasmid. 4) The recovery of the inoculated strains was up to 12.5 % in soybean cultivated soil and was up to 25 % in soybean uncultivated soil. 5) When the wild type or marked strains were inoculated. there was no significant effect on soybean plant, whereas the inoculation effect was pronounced in soybean uncultivated soil. The inoculation effect seemed to be more pronounced in wild type strains than antibiotic resistant strains. however, the difference was not significant.

• 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.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.169-178
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• 2010

The microbial community structure in Thailand soils contaminated with low and high levels of arsenic was determined by denaturing gradient gel electrophoresis. Band pattern analysis indicated that the bacterial community was not significantly different in the two soils. Phylogenetic analysis obtained by excising and sequencing six bands indicated that the soils were dominated by Arthrobacter koreensis and $\beta$-Proteobacteria. Two hundred and sixty-two bacterial isolates were obtained from arsenic-contaminated soils. The majority of the As-resistant isolates were Gramnegative bacteria. MIC studies indicated that all of the tested bacteria had greater resistance to arsenate than arsenite. Some strains were capable of growing in medium containing up to 1,500 mg/l arsenite and arsenate. Correlations analysis of resistance patterns of arsenite resistance indicated that the isolated bacteria could be categorized into 13 groups, with a maximum similarity value of 100%. All strains were also evaluated for resistance to eight antibiotics. The antibiotic resistance patterns divided the strains into 100 unique groups, indicating that the strains were very diverse. Isolates from each antibiotic resistance group were characterized in more detail by using the repetitive extragenic palindromic-PCR (rep-PCR) DNA fingerprinting technique with ERIC primers. The PCR products were analyzed by agarose gel electrophoresis. The genetic relatedness of 100 bacterial fingerprints, determined by using the Pearson product-moment similarity coefficient, showed that the isolates could be divided into four clusters, with similarity values ranging from 5-99%. Although many isolates were genetically diverse, others were clonal in nature. Additionally, the arsenic-resistant isolates were examined for the presence of arsenic resistance (ars) genes by using PCR, and 30% of the isolates were found to carry an arsenate reductase encoded by the arsC gene.

• Korean Journal of Veterinary Service
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• v.29 no.3
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• pp.277-285
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• 2006

Plasmids are covalently closed circular molecules of DNA that are stably inherited and replicate somewhat independently of the bacterial chromosome. Genes carried on plasmids can mediate a wide variety of important functions, including antibiotics (R plasmids) and heavy metals resistance, toxins production, cell penetration, iron chelation, complement resistance, and metabolic characteristics such as sucrose and lactose fermentation. Fifty strains of lactobacilli were isolated from 26 staters and 29 fermented milk products. They were classified 27 strains as Lactobacillus paracasei subsp paracasei, 11 stains as Lactococcus lactis subsp cremoris, 6 strains as L delbrueckii subsp lactis, 4 strains as L acidophius, and 2 strains as L delbrueckii subsp bulgaricus. All of these strains were examined for drug resistance and transferability of R plasmids. All of the isolates were sensitive to Am, C, CF, E, NB, P, T, and Te. But resistant to SXT 94% (47 strains), K 66% (33 strains), S 56% (28 strains), ENR 50% (25 strains), NOR 38% (19 strains) CIP 38% (19 strains), GM 16% (8 strains), and N 14% (7 strains), in order. And 32 different resistant patterns were found. The most frequently encountered patterns were CIP-ENR-K-NOR-S-SXT (5 strains). In vitro R plasmids transfer experiment, 57 antibiotic resistant strains which were not transfer to the recipient 2 Escherichia coli strains by conjugation, These results indicate that Lactobacillus in internal trade market' stater recognize R factor but transmissible R plasmid is not existed.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.229-235
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• 2016

Infective endocarditis (IE) caused by methicillin-resistant Staphylococcus aureus (MRSA) has become a worldwide concern. We present a case of a 12-year-old child with IE of the native mitral valve due to MRSA infection after an invasive dental procedure. Based on the clinical symptoms and the presence of cerebrospinal fluid pleocytosis, the patient was initially diagnosed with presumed bacterial meningitis and treated with empiric antibiotics. On the third day of hospitalization, MRSA was cultured from the initial blood samples and vegetation was observed on the mitral valve during an echocardiogram, findings which are compatible with a diagnosis of IE. The revised guidelines for antibiotic prophylaxis for the prevention of IE advise that IE prophylaxis for dental procedures is reasonable only for patients with underlying cardiac conditions, who are at the highest risk of adverse outcomes from IE. However, in this case, the patient had no high risk factors indicative of IE prophylaxis, except for mitral valve prolapse. She had no recurrence of IE over a follow-up period of 12 months.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.79-84
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• 2002

Purpose : About 41% of obtained group A streptococci in the 1998 was reported as erythromycin-resistant streptococci in Seoul, Korea. The most common T serotype was T12, followed by T4 and T28. We'd like to monitor the serological changes and antibiotic sensitivity test of Streptococcus pyogenes obtained from the patients with pharyngotonsillitis and invasive diseases from 1999 through 2001. Also, it could be proposed to choose the proper antibiotic selection in the area where the rate of erythromycin-resistant streptococci is high. Methods : From Jan. 1999 to Oct. 2001, 208 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis, scarlet fever, and invasive infections in Seoul and Southern part of peninsula. All isolates were serotyped by T-agglutination, minimum inhibitory concentrations(MICs) which were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). Results : The most common T serotype was T12(29.8%), followed by T1(23.1%), T4 (14.9%). T1 was prominent serotype compared with previous year. T serotyping, among 25 isolates obtained from the patients with scarlet fever in Southern part of peninsula mostly, was T12, T1, and T4 in order of frequency. All the isolates tested were susceptible to penicillin, cefprozil, vancomycin, ceftriaxone, and chloramphenicol. However, 23 isolates(14.2%) was resistant to erythromycin and 18 isolates(11.1%) was resistant to clarithromycin. Serotype T12 was found to be the most resistant serotype to erythromycin and/or clarithromycin. Conclusion : High rate of erythromycin-resistant streptococci which surveyed in 1998 were reduced to 14.2% in this study. We should have to further evaluate the reason of decreased resistant strains and consider the resistant strains of streptococci in choosing the antibiotics. There was no serological characteristics according to the types of disease entities. Between the serologic distributions in Seoul and the Southern part of peninsula area are same, we could presume that the serological typing of strains obtained over the country may be not different.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.2
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• pp.68-74
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• 2011

Pseudomonas aeruginosa is an aerobic, Gram-negative, glucose-nonfermenting bacterium, which has emerged as a serious opportunistic pathogen. Recently, outbreaks of carbapenem resistant P. aeruginosa give rise to significant therapeutic challenges for treating nosocomial infections. The genes of metallo-${\beta}$-lactamase (MBL), a powerful carbapenemase, are carried as a part of the mobile gene cassettes inserted into integrons playing an important role in rapid dissemination of antibiotic resistance genes among bacterial isolates. In this study, we investigated the prevalence of integron in imipenem resistant P. aeruginosa isolates. A total of 61 consecutive, non-duplicate, and imipenem resistant P. aeruginosa strains were isolated from a university hospital in the Chungcheong province of Korea. We employed repetitive extragenic palindromic sequence-based PCR (rep-PCR) method for the selection of clonally different P. aerusinosa strains. PCR and DNA sequencing were conducted for the detection of integrons. Twenty-one clonally different P. aeruginosa strains were isolated. Only one (P28) of the strains harbored $bla_{VIM-2}$ that was found as gene cassettes in class 1 integrons. Four of 21 carbapenem resistant P. aeruginosa strains harbored class 1 integron containing aminoglycoside resistance determinant. All of the integrons detected in the study contained more than one resistance gene cassette, which can mediate resistance to multiple antibiotics. To prevent further spreading of the multi-drug resistant P. aeruginosa, conseguent monitoring and clinical polices are required.

• Journal of Home Health Care Nursing
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• v.30 no.2
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• pp.155-162
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• 2023

Purpose: This study was conducted to identify the status and risk factors for the carriage of multidrug-resistant organisms carriage in home health nursing patients. Methods: This retrospective study enrolled 122 participants who received home health nursing and analyzed the data obtained from chart review and diagnostic tests for multidrug-resistant organisms carriage from January 2019 to January 2021. Results: Multivariate analysis revealed that surgical procedures in the preceding year, injectable antibiotic use in the preceding month, pressure ulcer, and indwelling nasal tubes were significantly associated with multi-drug resistant infection. Conclusions: Infection-control strategies need to be developed and customized for use in the home health-nursing service for patients who are carriers of multidrug-resistant organisms.

• Food Science of Animal Resources
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• v.33 no.4
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• pp.481-486
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• 2013

This study evaluates the effects of fat contents on the thermal resistance, antibiotic sensitivity, and Caco-2 cell invasion of Listeria monocytogenes. Ten strain mixture of L. monocytogenes in milk (0, 1, and 4% fat) and pork sausage patties (10, 20, and 30% fat) were exposed to $63^{\circ}C$. To evaluate effects of fat on the antibiotic sensitivity of L. monocytogenes, the L. monocytogenes strains NCCP10811 (most antibiotic resistant to streptomycin) and NCCP10943 (most antibiotic sensitive to streptomycin) were exposed to different fat contents in milk and pork sausage patties, and L. monocytogenes from the foods were used for antibiotic sensitivity assays. The most invasive L. monocytogenes strains (NCCP10943) was exposed to different fat contents in milk or pork sausage patties, and L. monocytogenes from the foods were used for the Caco-2 cell invasion assays. The reductions of L. monocytogenes populations were not generally influenced by fat contents. The L. monocytogenes subjected to milk fat had increased sensitivities (p<0.05) due to some antibiotics. In addition, Caco-2 cell invasion efficiency of L. monocytogenes NCCP10943 increased (p<0.05) as fat contents increased. These results indicated that higher fat contents may be related to L. monocytogenes invasions and heat resistances in pork sausage patties, but the relationship between fat and antibiotic sensitivity varied according to antibiotics, strains, and fat contents.