• Korean Journal of Microbiology
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• v.20 no.1
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• pp.11-20
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• 1982

A study was undertaken to examine the effect of curing agents on the stability, curing and segregation of R plasmid pSL100. And also the stability, transfer frequency, and recombination of its segregants obtained from curing agent treatment were studied. Ethidium bromide, acridine orange, and mitomycin-C were used as curing agent. The results obtained were as follows ; 1. The curing agent ethidium bromide, acridine orange, and mitomycin-C were not effective for curing the multiple antibiotic resistant determinant of pSL100 in Salmonella typhimurium and Escherichia coli. However, they induced plasmid segregation with high frequency in S.typhimuruim LT-2strains. TcApSmCm, TcSmCmKm, TcApCm, TcAp, TcKm, Tc segregants were obtained. 2. The resistant markers of the segregents were transferred to S.typhimurium LT-2 strains with high frequencies whereas they were transferred to E.coli K-12 only with low frequencies. 3. The transconjugants obtained from conjugation between two different S.typhimurium segregants were similar to the phenotype of the original R factor pSL100 and the resistant markers were transferred to the S.typhimurium LT-2 or E.coli strain with equal frequencies, indicating that they are recombinants. 4. The transconjugants obtained from conjugation between pSL100 segrgants and pKM101, or pBR322 possessed the resistant markers of the two parental plasmids and they were transferred to both S.typhimurium and E.coli K-12 strains with the same frequencies and maintained stably, suggesting that they are also recombinants. 5. The recombinant pSL100 could be also obtained in rec A-strains of E.coli, suggesting that the gene function of rec A is required for the recombination of pSL100 segregants in E.coli.

• Journal of Environmental Health Sciences
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• v.39 no.3
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• pp.239-246
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• 2013

Objectives: Antimicrobial resistance and multidrug resistance patterns have been studied with a total of 189 samples of Salmonella Enteritidis and Salmonella Typhimurium isolated from diarrhea patients in Incheon from 2008 to 2012. Methods: Antimicrobial resistance tests were determined by Disc Diffusion method. Results: The serological distribution of Salmonella spp. showed 108 strains (30.1%) of S. Enteritidis, 81 strains (22.6%) of S. Typhimirium, eight strains (8.0%) of S. Typhi, 11 strains ( 3.1% ) of S. Paratyphi, and the 151 other strains (42.1%). The separation rate of Salmonella spp. by year showed 14.5% (52 strains) in 2008, 13.6% (49 strains) in 2009, 22.8% (82 strains) in 2010, 25.3% (91 strains) in 2011, and 23.7% (85 strains) in 2012. Additionally, the separation rate of S. Enteritidis and S. Typhimirium in 2010 was the highest. The Salmonella spp. isolated from diarrhea patients showed significant differences according to age (p<0.05), gender (p<0.01) and medical institution (p<0.05). The highest resistance was found to the following antimicrobial agents: imipenem 77 strains, ampicillin 47 strains, ciprofloxacin 34 strains, nalidixic acid 29 strains for S. Enteritidis, and ampicillin 45 strains, nalidixic acid 45 strains for S. Typhimurium. Separated S. Enteritidis and S. Typhimurium resistance to the antibiotics by the year showed significant differences (p<0.05). The patterns of multidrug resistance rates were 43.1% (47 strains) for one drug, 8.3% (9 strains) for two drugs, 11.0% (12 strains) for three drugs, 15.62% (17 strains) for four drugs, and 13.7% (15 strains) for five or more drugs for S. Enteritidis. For S. Tyhpimurium, the rates were 15.0% (12 strains) for one drug, 10.0% (8 strains) for two drugs, 6.3% (five strains) for three drugs, 18.7% (15 strains) for four drugs, and 23.8% (19 strains) for five or more drugs. Conclusion: The antibiotic resistance issue is directly related to people's lives. Thus, the usage of antibiotics should be reduced in order to manage antibiotic resistance.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1110-1114
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• 2002

Antimutagenic effect of Eleutherococcus senticosus Maxim. on the mutagenicity induced by 2-AF and Trp-P-1 was studied using the Ames test with Salmonella typhimurium TA98 and TA100. In S. typhimurium TA98, the methanol extract $(500\;{\mu}g/plate)$ of root, stem, and leaf of E. senticosus showed inhibitory effects of 72.8, 70.0, and 78.7% on the mutagenicity induced by 2-AF, and 69.2, 64.9, and 59.4% by Trp-P-1, respectively, whereas none was observed in S. typhimurium TA100. These results suggest that the methanol extract of E. senticosus inhibits a frame shift mutation. And then the methanol extract further fractionated by chloroform, butanol, and water. The chloroform fractions of root, stem, and leaf showed strong antimutagenic effects induced by 2-AF and Trp-P-1 in S. typhimurium TA98, whereas none was observed in the butanol and aqueous fractions. The chloroform fractions of root, stem, and leaf showed antimutagenic effects of $13{\sim]92%$ in a dose-dependent manner.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.171-171
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• 1994

Cephem ring의 C-7위치에 aminothiazoly lmethoxyimino기를 가진 화합물들이 항균활성을 증가시키고, G(-)균의 외막투과성을 촉진시킬뿐 아니라 광범위항균 spectrum을 갖게 하고 $\beta$-lactamase에 안정하며 PBP(penicillin binding protein)에 대한 결합친화성을 증가시킨다는 보고에 따라 본 저자는 C-7위치에 cefotaxime구조와 같이 aminothiazolylmethoxyimino acetamido moiety를 고정시키고 항균활성을 증가시키기 위하여 약리활성이 기대되는 5-(substituted)-2H-tetrazole유도체들을 합성하여 C-3 위치에 도입시킨 새로운 화합물 7$\beta$-〔(z)-2-(2-aminothiazol-4-yl)-2_(methoxyimino)acetamido〕-3-〔5-(substituted)tetrazol-2-yl〕 methyl-3-cephem-4-carboxylic acid 유도체를 합성하여 B. subtilis ATCC 6633, M. luteus ATCC 1004, E. coli KCTC 1039, E. coli ESS, K. pncumonia KCTC 1560, P. aeruginosa IF0 13130, S. typhimurium KCTC 1925, S. typhimurium SL 1102, 및 C. albicans ATCC 10231 등의 균과 fungus에 대하여 기존의 cefotaxime과 cefazoline을 대조물질로 사용하여 항균력을 비교하였다. 이들 화합물들은 대체적으로 M. luteus ATCC 6633, E. coli ESS, S. typhimurium SL 1102 균에 대해서는 cefotaxime보다 항균력이 우수하였으나 P. aeruginosa IF0 13130에 대해서는 항균력이 저하되었고 cefazolin보다는 대체적으로 항균력이 우수하였다.

• International Journal of Human Ecology
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• v.7 no.1
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• pp.145-153
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• 2006

Hwangryeon (Coptidis rhizoma) was extracted by methanol and its antimicrobial activities against food spoilage and foodborne disease microorganisms were investigated by the paper-disc method. The microorganisms used in this experiment included 5 species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella pneumoniae, and Staphylococcus aureus) and 3 species of fungi (Fusarium solani, Aspergillus flavus, and Penicillium citreonigrum). The Hwangryeon extract showed antimicrobial effect against P. aeruginosa, S. aureus, S. typhimurium, and K. pneumonia. The minimum inhibitory concentration on S. aureus, S. typhimurium, and K. pneumoniae was 300 mg/mL, but on P. aeruginosa it was 200 mg/mL. In the methanol extracts from Hwangryeon, 190 compounds were separated by GC/MS. The extraction yields of phenols, furans, alcohols, acids and esters, ketones, and miscellaneous compounds were 28.10%, 2.67%, 1.79%, 12.89%, and 2.35%, respectively. The phenolic compounds, generally understood to be an antimicrobial active substance, was measured at 28.10%, a relatively remarkable amount.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.765-769
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• 2005

The essential oil fraction of Ostericum koreanum was analyzed by GC-MS. Inhibiting activities of this oil and its main components were tested by the broth dilution assay and disk diffusion test against one antibiotic-susceptible and two resistant strains of Salmonella enteritidis and S. typhimurium, respectively. The GC-MS analysis revealed thirty-four compounds; the main components were $\alpha$-pinene (41.12%), $\rho$-cresol (17.99%) and 4-methylacetophenone (7.90%). The essential oil of O. koreanum and its main components were significantly effective against the tested antibiotic-susceptible strains as well as against the resistant strains of the two Salmonella species, with MICs (minimum inhibitory concentrations) ranging from 2 mg/mL to 16 mg/mL. The anti-Salmonella effects of the oils were dose-dependent on $M\"{u}ller-Hinton$ agar plates in this experiment. Additionally, checkerboard titer test results demonstrated significant combined effects of streptomycin and O. koreanum oil or cresol, one of the main components of this oil, against the two streptomycin resistant strains of S. typhimurium, with FICIs ranging from 0.12 to 0.37.

• Food Science and Preservation
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• v.15 no.5
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• pp.774-781
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• 2008

was performed and Staphylococcus sciuri, Bacillus cereus, Escherichia coli, Proteus mirabilis, and Enterococcus faecalis were identified. No Salmonella strain, a typical contaminant of eggs, was found. The radiation sensitivities of isolated bacteria and Salmonella typhimurium, in an inoculated model system, were expressed in $D_{10}$ values. The ranges of $D_{10}$ values shown by S. typhimurium, S. sciuri, B. cereus, E. coli, P. mirabilis, and E. faecalis were 0.365-0.399 kGy, 0.418-0.471 kGy, 1.075-1.119 kGy, 0.280-0.304 kGy, 1.132-1.330 kGy, and 0.993-1.290 kGy, respectively. The growth of all six test bacteria in eggs (inoculated at $10^6-10^7\;CFU/g$) during 3 days of post-irradiation storage at ambient conditions ($25^{\circ}C$) was recorded. S. typhimurium was eliminated by irradiation at 3 kGy, and E. coli and S. sciuri were eliminated by irradiation at 5 kGy. The viable cell counts of B. cereus, P. mirabilis, and E. faecalis in eggs showed 4-6 log reductions after irradiation with 5 kGy.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.861-864
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• 2008

Enterobacter sakazakii, Salmonella typhimurium. and Bacillus cereus were evaluated on inoculated infant formula by gamma irradiation treatment as a method to provide microbial safety. The infant formula inoculated with the major pathogenic bacteria was treated at irradiation dose of 0, 3, 5, and 10 kGy, respectively. After treatment, the samples were individually packaged and stored at $20^{\circ}C$. Microbiological data during storage represented that the populations of E. sakazakii, S. typhimurium, and B. cereus were reduced with the increase of irradiation dose by 4 to 5 log reductions. In particular, E. sakazakii, S. typhimurium. and B. cereus were eliminated at 10, 5, and 3 kGy, respectively. E. sakazakii was the most radiation-resistant, while B. cereus was the least. Our results represent that gamma irradiation below 10 kGy should eliminate the growth of the major pathogenic bacteria in infant formula during storage.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1271-1279
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• 2009

To develop low endotoxic and multi-immunogenic outer membrane vesicles (OMVs), a deletion mutant of the msbB gene in Salmonella enterica serovar Typhimurium (S. Typhimurium) was used as a source of low endotoxic OMV, and an expression vector of the canine parvovirus (CPV) VP2 epitope fused to the bacterial OmpA protein was constructed and transformed into the Salmonella ${\Delta}msbB$ mutant. In a lethality test, BALB/c mice injected intraperitoneally with the Salmonella ${\Delta}msbB$ mutant survived for 7 days, whereas mice injected intraperitoneally with the wild type survived for 3 days. Moreover, all mice inoculated orally with the ${\Delta}msbB$ mutant survived for 30 days, but 80% of mice inoculated orally with the wild type survived. The OmpA::CPV VP2 epitope fusion protein was expressed successfully and associated with the outer membrane and OMV fractions from the mutant S. Typhimurium transformed with the fusion protein-expressing vector. In immunogenicity tests, sera obtained from the mice immunized with either the Salmonella msbB mutant or its OMVs containing the OmpA::CPV VP2 epitope showed bactericidal activities against wild-type S. Typhimurium and contained specific antibodies to the CPV VP2 epitope. In the hemagglutination inhibition (HI) assay as a measurement of CPV-neutralizing activity in the immune sera, there was an 8-fold increase of HI titer in the OMV-immunized group compared with the control. These results suggested that the CPV-neutralizing antibody response was raised by immunization with OMV containing the OmpA::CPV VP2 epitope, as well as the protective immune response against S. Typhimurium in BALB/c mice.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.609-615
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• 2005

The safety and immunogenicity of an attenuated recombinant Salmonella vaccine strain, Salmonella enterica serovar Typhimurium llaB, was assessed. This vaccine strain could survive in low pH condition, and its ability of intracellular survival did not differ from that of S. enterica serovar Typhimurium UK1, which is the wild-type of the vaccine strain. The mortality of the mice orally administered with the vaccine strain was $50\%$ at the dose of $10^7$ CFU. All mice administered with $10^5\;or\;10^3$ CFU of the vaccine strain survived for 3 days postinoculation (pi). However, all mice administered with more than $10^3$ CFU of the vaccine strain died within 3 days pi. To examine the protective effect of the vaccine strain, mice were orally immunized with $10^4\;and\;10^6$ CFU of the bacteria. Control mice were given with 0.5 ml of phosphate buffered saline (PBS). After 8 days, the mice were challenged with $10^9$ CFU of S. enterica serovar Typhimurium UK1, and mortality was examined for 5 days. The survival rates of the mice immunized with $10^4\;and\;10^6$ CFU of the vaccine strain were $60\%\;and\;80\%$, respectively, whereas all control mice died within 2 days after challenging. To investigate the immunogenicity of S. enterica serovar Typhimurium llaB, mice were orally immunized with $10^5\;or\;10^6$ CFU ml of the vaccine strain. Five mice of each group were sacrificed at 5 and 12 days after immunization, and results showed that immunization of the vaccine strain led to increases of IgG1, IgG2, and IgM titers against S. enterica serovar Typhimurium UK1 in mouse sera, cytokine expressions such as IL-2, IL-4, IL-6, and IL-10 in spleen, and the lymphocyte proliferation response to mitogens (concanavalin A or LPS) stimulation.