• Korean Journal of Veterinary Service
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• v.23 no.1
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• pp.19-28
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• 2000

There are several main antibacterial susceptibility tests, such as agar dilution method, broth dilution method and disk diffusion technique. Especially, for minimal inhibitory concentration (MIC) test, agar dilution method has been widely used. But that method is so complicated and bothering that it's difficult to treat a large amount of strains. On the other hand, modified broth dilution method(add 1% glucose and 0.018% phenol red as a pH indicator to broth) is fast and easy to perform. Most of all, it can visualize the result by color. The MICs of 22 antibiotics Including penicillins, aminoglycosides, cephalothin, chloramphenicol, lincomycin, ceftiofur, vancomycin and quinolones, erythromycin, colistin. sul-fadimethoxine, trimethoprim for arcanobacterium pyogenes 14 strains, actinobacillus pleuropneu-moniae 41 strains and pasteurella multocida 37 strains, which were collected from porcine during 1996 ∼ 1999, were determined by modified broth dilution method. Actinobacillus pleuropneumoniae was highly susceptible to all kinds of quinolones such as ciprofloxacin, enrofloxacin and norfloxacin and to all aminoglycosides, like gentamicin, apramycin, kanamycin and ampicillin, cephalothin and ceftiofur. But It was quite resistant to solfadimethoxin, colistin and vancomycin. Pasteurella multocida was found to have high susceptibility to ampicillin, cephalothin, chlorampenicol and gentamicin but had mid-degree susceptibility to other aminoglycosides. In addition, it was susceptible to norfloxacin and nalidixic acid, but not to newer fluoroquinolone like ciprofloxacin and enrofloxacin and it was resistant to colistin and kanamycin. Arcanobacterium pyogenes was highly susceptible to most of quinolones such as cipoofloxacin, enrofloxacin and norfloxacin and gentamicin and penicillin G. But it also obtained high resistance against the early quinolone, nalidixic acid and aminoglycosides such as amikacin, apramycin and kanamycin and erythromycin, chlorampenicol, tetracyclin and vancomycin.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.301-307
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• 1987

A total of 42 strains of Candida albicans were examined for susceptibility to three antifungal agents, amphotericin B(AMB), 5-fluorocytosine(5-FC), and ketoconazole(KTZ), using defined medium, synthetic amino acid medium-fungal(SAAM-F), supplemented yeast nitrogen base(SYNB) and undefined medium Sabouraud's dextrose broth(SDB) and Kimmig broth media. A tube dilution method was used with minimum inhibitory concentrations(MICs) determined after incubation for 24 hour and 48 hours. All testes were performed in duplicate. In general, MICs were more reproducible after 48 hour of incubation. Forthermore, MICs determined after incubation for 48 hours were significantly higher than those determined after 24 hours. The actural MICs obtained with the different antifungal agents were clearly influenced by the test medium used. The rank order of AMB MICs according to the test medium was as follows: SAAM-F>SYNB>SDB>Kimmig broth. With 5-FC, the following pattern was observed: SYNB>SAAM-F>SDB>Kimmig borth. For ketoconazole, the MICs according to the test medium was SAAM-F>SDB>SYNB> Kimmig broth. In amphotericin B, the MICs mean value with the test medium was as follows: SDB, 0.24 mcg/ml; Kimmig broth, 0.29 mcg/ml; SYNB, 0.21 mcg/ml and SAAM-F, 0.15mcg/ml. The actural value of 5-FC was; SDB, 37.20 mcg/ml; Kimmig broth, 67.41mcg/ml; SYNB, 21.29 mcg/ml and SAAM-F, 24.61 mcg/ml and in ketoconazole, the MICs value was; SDB, 1.83 mcg/ml; Kimmig broth, 4.08 mcg/ml; SYNB, 1.95 mcg/ml and SAAM-F, 1.41 mcg/ml. The results of this investigation suggested that broth dilution susceptibility testing of yeast and yeast-like fungi are best performed with an incubation period of 48 hours. Furthermore, medium composition can significantly influence the results of such testing.

• Journal of Wellbeing Management and Applied Psychology
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• v.5 no.3
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• pp.1-5
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• 2022

Purpose: The purpose of this study is to investigate whether wetland has antimicrobial activity on pathogenic bacteria in the toilet bowl. Research design, data and methodology: Air-dried mud obtained from "Jilmoe Bog" wetland was packed and dissolved in the autoclaved saline. Antimicrobial susceptibility was assessed against three Gram-negative bacteria using disk diffusion method and broth dilution method. Identification of specific bacterium presented in wetland supernatant was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Results: Incubation of three Gram-negative bacteria with wetland supernatant inhibited bacterial growth of the bacteria, otherwise increased prevalence of specific bacterium. It was confirmed that Pseudomonas putida was presented in wetland supernatant. Conclusions: The results presented in this study might provide the possibility to utilize wetland supernatant as a bioremediation of toilet bowl bacteria.

• The Journal of the Korean Society for Microbiology
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• v.13 no.1
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• pp.43-48
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• 1978

The difference in antimicrobial susceptibility of multiply drug-resistant Salmonella typhi by the methods of test was tested against chloramphenicol(Cm), tetracycline(Tc), ampicillin(Ap), kanamycin(Km), and rifampicin(Rif), and the results were compared by the minimum inhibitory concentration(MIC). No appreciable difference was noted between MICs of Cm, Tc, and Rif measured by agar plate dilution(plate) method and broth dilution(broth) method. However, MICs of Km to about a half of test strains were 4 to 8-fold higher by broth method than plate method, and MICs of Ap by broth method were also a little higher than plate method in some strains. Cm and Rif were bacteriostatic rather than bactericidal to the most of test strains in high concentrations. Tc, Ap and Km were exclusively bactericidal to the test strains.

• Journal of Food Hygiene and Safety
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• v.15 no.1
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• pp.55-59
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• 2000

In order to develop a antimicrobial agent, dried bamboo trunk was extracted by high temperature suction and then antimicrobial activities against Staphylococcus aureus ATCC 2825 and Escherichia coli DH 5$\alpha$ were investigated as compared with tea tree oil and BHA. The minimal inhibitory concentrationo(MIC) of the extracted substance against microorganisms were also examined. The results are as follows: 1. By disc diffusion method, BHA showed the strongest antimicrobial activity on Gram-positive bacteria such as S. aureus ATCC 2825 but bamboo essential oil showed the strongest antimicrobial activity on Gram-negative bacteria such as E. coli DH 5$\alpha$. 2. By broth dilution method, the minimum inhibitory concentration of the BHA, tea tree oil and bamboo oil were not detected against S. aureus ATCC 2825(MIC, 6.0 $\mu$l/ ml) and E. coli DH 5$\alpha$(MIC, 6.0 $\mu$l/ ml)

• Korean Journal of Veterinary Service
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• v.32 no.4
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• pp.347-351
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• 2009

Bruella spp. involves a considerable danger of public health and farm animal industry. In this study, we assessed the disinfection efficacy of alkaline disinfectant solution and three commercial farm disinfectants (quaternary ammonium compound, sodium dichloroisocyanurate, potassium monopersulphate/sodium dichloroisocyanurate) against Brucella ovis. A bactericidal efficacy test by broth dilution method was used to determine the lowest effective dilution of selected disinfectants following exposure to test bacteria for 30 minutes at $4^{\circ}C$. Disinfectants and test bacteria are diluted with distilled water (DW), hard water (HW) or organic matter suspension (OM) according to treatment condition. Three commercial disinfectant showed excellent antimicrobial activity (up to dilution of $\times200$ in OM treatment). Alkaline disinfectant solution demonstrated favorable bactericidal efficacy against B. abortus (at dilution of $\times20$ in OM treatment). Three commercial farm disinfectants possess excellent efficacy against B. ovis. Alkaline disinfectant solution has lower potency than commercial farm disinfectant but could help to limit the spread of brucellosis.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.202-215
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• 1996

The purpose of this study was to an in estigate the antibiotic susceptibiliity of Actinoobacillus actinomycetemcomitans isolated from the subgingival plaque to adult periodontitis. Seven bacterial strains were tested for their susceptibility to 10 antimicrobial agents under disk diffusion method and broth dilution methold, Seven patients with deep pocket(6mm) were selected for this study. They had not taken antibiotics for 6 months and no history of dental treatment for 6 months and no history of dental treatment for 6 months before this study. The results were as follows : 1. For the antibiotic disk diffusion method, seven A. actinimycetemcomitans were tested with 10 antimicrobial agents which comprised penicillin, gentamycin, clindamycin, lincomycin, ampicillin, erythromycin, tetracycline, amikacin, chloramphenicol, and vancomycin. The sensitive antibiotics were tetracycline, vancomycin, and chloramphenicol and the resistant antibiotics were clindamycin, and lincomycin. The other antimicrobial agents were less active. 2. From the study of determination on the minimal inhibitory concentration(MIC) by broth dilution method, the MIC of tetracycline to seven strains of the A. actinomycetemcomitans was $0.5-1.0{\mu}g/ml$, that of clindamycin was $32{\mu}g/ml$. These data suggest that tetracycline may be valuable drugs in the elimination of A. actinimycetemcomitans from the patients with adult periodontitis

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.500-510
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• 2023

In this study, lactic acid bacteria were isolated from 21 top-selling probiotic products on Korean market and their antimicrobial resistance were analyzed. A total 152 strains were claimed to be contained in these products and 70 isolates belonging to three genera (Bifidobacterium, Lactobacillus, and Lactococcus) were obtained from these products. RAPD-PCR showed diversity among isolates of the same species except for two isolates of Lacticaibacillus rhamnosus from two different products. The agar dilution method and the broth dilution method produced different MICs for several antimicrobials. With the agar dilution method, five isolates (three isolates of Bifidobacterium animalis subsp. lactis, one isolate of B. breve, one isolate of B. longum) were susceptible to all nine antimicrobials and 15 isolates were multi-drug resistant. With the broth microdilution method, only two isolates (one isolate of B. breve and one isolate of B. longum) were susceptible while 16 isolates were multi-drug resistant. In this study, only two AMR genes were detected: 1) lnu(A) in one isolate of clindamycin-susceptible and lincomycin-resistant Limosilactobacillus reuteri; and 2) tet(W) in one tetracycline-susceptible isolate of B. longum B1-1 and two tetracycline-susceptible isolates and three tetracycline resistant isolates of B. animalis subsp. lactis. Transfer of these two genes via conjugation with a filter mating technique was not observed. These results suggest a need to monitor antimicrobial resistance in newly registered probiotics as well as probiotics with a long history of use.

• YAKHAK HOEJI
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• v.40 no.6
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• pp.653-658
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• 1996

As part of our search for less toxic antimicrobial agents from natural resources. rutin was isolated from Sophora japonica and then hydrolyzed to quercetin. Antimicrobial activity of quercetin was tested in vitro against five kinds of gram positive and ten kinds of gram negative bacteria by serial broth dilution method. Among fifteen kinds of bacteria tested, the antimicrobial activity of quercetin was the most potent against Proteus vulgaris showing minimal inhibitory concentration(MIC) of 125 ${\mu}$g/ml. To investigate the effect of antimicrobial combinations of quercetin with four kinds of antibiotics (ampicillin, cefazolin, oxytetracycline and chloramphenicol). the fractional inhibitory concentration index (FICI) was determined by checkerboard assay for each strain. The antimicrobial combinations of quercetin with four kinds of antibiotics resulted in synergism in one instance, additive effect in four instances, but no antagonism was observed.

• Journal of Korean Biological Nursing Science
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• v.12 no.2
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• pp.73-80
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• 2010

Purpose: We tested the inhibitory effect of six purchasable alcohol hand rubs against Staphylococcus aureus. Methods: Five alcohol hand rubs were collected with random manner on the market and 1 alcohol hand rubs which is currently used in a hospital was included. we designed the experimental scheme on the basis of M7-A6 method of NCCLS. Each hand rubs were diluted to 1:1, 1:10, 1:100, 1:1,000 with tryptic soy broth. S. aureus was cultured. Turbidity and the colony counting was measured. Results: With dilution rate of 1:1, all products showed more than 95% of the inhibitory effect on bacterial growth. At 1:10 dilution, product $N^{\circ}1$, 2, 3, 4, and 5 displayed the inhibitory effect of 97.77%, 92.38%, 78.19%, 97.42%, and 96.6%, respectively. But, the inhibitory effect of product $N^{\circ}6$ has been disappeared at that dilution. Over 1:100 dilution, all products lost their inhibitory effect except product $N^{\circ}5$. Product $N^{\circ}5$ displayed more than 96% of inhibitory effect at all dilution rate, even at 1:100 and 1:1,000. Conclusion: We identified that inhibitory effect on bacterial growth of alcohol hand rubs was variable. We suggest that concentration of alcohol should be checked before choosing alcohol hand rubs. Further evaluation of in vivo study is needed.