• Journal of Food Hygiene and Safety
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• v.23 no.1
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• pp.62-67
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• 2008

Inactivation of Salmonella Typhimurium and Listeria monocytogenenes in mandarin orange, Prunus mume (maesil), and kiwi juices was evaluated. A three-strain mixture of S. Typhimurium or L. monocytogenes was inoculated (7 log CFU/ml) into a commercial mandarin orange juice and maesil juice, and home-maid kiwi extract. The inactivation effect of Maesil juice was estimated by the addition into the other two fruit juices. All fruit juices had acidic pH, ranging from 2.8 to 3.5 and it was not variable during all experimental period, being at $4^{\circ}C$ for 14 days, The present study demonstrated that Maesil juice inactivated throughly L. monocytogenes within 7 days, while kiwi extract and mandarin orange juice archived 3.0-log inactivation and 1.0-log inactivation, respectively, until 14 days of storage. S. Typhimurium was completely reduced by Maesil juice and kiwi extract within 14 days, but mandarin orange juice showed only 1.4-log inactivation. The inactivation of L. monocytogenes and S. Typhimurium was increased by adding 10% maesil juice to both mandarin orange juice and kiwi extract.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1042-1052
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• 2010

Forty-seven Salmonella Typhimurium (33 zoonotic, 14 clinical) strains were tested for antimicrobial resistance using the standard disk diffusion method. The presence of relevant resistance genes and class 1 integrons were investigated by using PCR. Pulsed-field gel electrophoresis (PFGE) and plasmid profiling were carried out to determine the genomic diversity of Salmonella Typhimurium. Approximately 57.4% of the S. Typhimurium strains were multidrug resistant (MDR) and showed high resistance rates to tetracycline (70.2%), sulfonamides (57.4%), streptomycin (53.1%), ampicillin (29.7%), nalidixic acid (27.6%), kanamycin (23.4%), chloramphenicol (21.2%), and trimethoprim (19.1%). Resistance towards cephalosporins was noted for cephalothin (27.6%), cephradine (21.2%), amoxicillin clavulanic acid (17.0%), and cephalexin (17.0%). Resistance genes, $bla_{TEM}$, strA, aadA, sul1, sul2, tetA, tetB, and tetC, were detected among the drug-resistant strains. Thirtythree strains (70.2%) carried class 1 integrons, which were grouped in 9 different profiles. DNA sequencing identified sat, aadA, pse-1, and dfrA genes in variable regions on class 1 integrons. Thirty-five strains (74.4%) were subtyped to 22 different plasmid profiles, each with 1-6 plasmids (2.0 to 95 kb). PFGE subtyped the 47 strains into 39 profiles. In conclusion, high rates of multidrug resistance were found among the Malaysian Salmonella Typhimurium strains. The emergence of multidrug-resistant Salmonella Typhimurium to cephalosporin antibiotics was also observed. The strains were very diverse and no persistent clone was observed. The emergence of MDR Salmonella Typhimurium is a worldwide problem, and this report provides information for the better understanding of the prevalence and epidemiology of MDR S. Typhimurium in Malaysia.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.358-367
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• 1983

Antibiotic-resistant strains of Salmonella typhimurium and Klebsiella pneumoniae died readily after their addition to raw sewage, but they grew in sterilized sewage. The decline was not a result of antibiotic stresses, and because the bacteria were able to survive in large numbers for at least 15 days in solutions containing no organic nutrients, it was not a result of competition. Toxin production, bacteriophages, and Bdellovibrio did not cause the disappearance of the two bacterial species. A decline was also evident if the sewage was first passed through a $3-{\mu}m$ filter or treated with cycloheximide or cycloheximide plus nystatin, but protozoa developed under these conditions. Little or no decline occurred if the sewage was filtered and treated with the eucaryotic inhibitors before adding S. typhimurium or K. pneumoniae, and protozoa were not detected. S. typhimurium increased in abundance if cycloheximide, streptomycin, and erythromycin or large amounts of glucose were added to sewage. Tetrahymena thermophilus did not significantly reduce the population of S. typhimurium in buffer when the density of the bacterium was about $10^4/ml$. However, when more than $10^8$ Enterobacter agglomerans cells per ml were added to the buffer, T. thermophilus reduced the abundance of E. agglomerans and S. typhimurium to $10^6$ and 10/ml, respectively. The density of S. typhimurium was further decreased by a second increment of E. agglomerans cells. The disappearance of S. typhimurium and K. pneumoniae from sewage thus is the result of predation by protozoa. It is proposed that predators will eliminate a prey species from a natural environment when an alternate prey is present at concentrations above the threshold number for active feeing by the predator and when the rate of growth of the prey is less than the rate of predation.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.161-167
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• 2003

Identification of salmonellosis-infected commercial poultry flocks has become a pivotal component of efforts to reduce incidence of egg-associated transmission of S. enteritidis and S. typhimurium to humans. As a basic study for sanitary control of S. enteritidis and S. typhimurium, main food-borne pathogenic bacteria in eggs produced by domestic hens, commercial egg samples were tested for specific antibodies to whole cells of S. enteritidis and S. typhimurium and outer membrane protein(OMP) of S. typhimurium by ELISA to detect infection of S. enteritidis and S. typhimurium in various groups of hens. When the antibody titers of yolks from three commercial brand eggs were tested after diluting in the ratio from 1:100 to 1:1,600 with double dilution method, ELISA values of the specific antibodies could be shown as differences in dilution patterns by comparing with negative control egg. When the antibody titers of the yolks from two commercial brand eggs were tested after diluting in the ratio of 1:200 and 1:1,000, ELISA values of specific antibodies were different among same brand eggs. When the antibody titers of yolks from five eggs sampled randomly from twenty one commercial brand eggs were tested after diluting in the ratio of 1:1,000, ELISA value of the specific antibodies were shown generally high. ELISA values of 28.5, 30, and 28.5% of yolks from 21 brand eggs were shown low and similar to negative control egg in antibody titers to whole cells of S. enteritidis and S. typhimurium and OMP of S. typhimurium, respectively. The results demonstrated that ELISA test of egg yolk antibody could provide a highly sensitive indicator to detect contamination of S. typhimurium and S. enteritidis in poultry, and could be used effectively to reduce incidence of S. typhimurium and S. enteritidis infection in poultry.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1527-1535
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• 2009

Polyphosphate (polyP) plays diverse physiological functions in prokaryotes and eukaryotes, but most of their detailed mechanisms are still obscure. Here, we show that deletion of polyphosphate kinase (PPK), the principal enzyme responsible for synthesis of polyP, resulted in augmented expression of cAMP receptor protein (CRP) and rpoS and lowered $H_2O_2$ sensitivity in Salmonella Typhimurium ATCC14028. The binding of cAMP-CRP complex to rpoS promoter and further stimulation of its transcription were proved through electrophoretic mobility shift assay, lacZ fusion, and exogenous cAMP addition, respectively. The rpoS expression increased in cpdA (cAMP phosphodiesterase coding gene) mutant, further suggesting that cAMP-CRP upregulated rpoS expression. These results demonstrate that PPK affects oxidative stress response by modulating crp and rpoS expression in S. Typhimurium.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.641-646
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• 2005

An approximately 10-fold higher level of adherence of Salmonella typhimurium strain TML to Int-407 cells was observed with organisms grown in Luria broth or in high-iron containing medium than those grown in low-iron containing medium. Iron specifically enhanced adherence, while other cations such as calcium, cobalt, copper, potassium, magnesium and manganese did not. It was suggested that iron did not act as a passive ligand - probably it stimulated production of bacterial factors necessary for adherence. A similar pattern of iron modulation of adhesiveness was also seen in Salmonella mutants with single or different combinations of multiple mutations in genes encoding the mannose sensitive hemagglutinin (type 1 fimbriae), mannose resistant hemagglutinin and flagellum. The adhesiveness of an isogenic fur mutant was modulated by iron in a manner similar to the wild-type strain, suggesting that iron modulation of adherence is independent of the fur gene product.

• Food Science and Biotechnology
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• v.15 no.4
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• pp.511-515
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• 2006

Antibiotic resistance of foodborne pathogens adapted to garlic (Allium sativum Linn.) was determined in order to understand the relationship between antibiotic resistance and garlic. The Gram (-) strains of Escherichia coli and Salmonella typhimurium and the Gram (+) strains of Bacillus cereus and Staphylococcus aureus were subcultured consecutively in a garlic broth, and the surviving colonies on the agar were selected as the adapted strains. Minimal inhibitory concentrations (MIC) for 15 antibiotics on the adapted strains were determined on Muller-Hinton Infusion agar. Adaptation to 1.3%(v/v) garlic juice increased MIC for vancomycin, aminoglycoside, and erythromycin on B. cereus, and for ampicillin and erythromycin on E. coli O157:H7. MIC of aminoglycosides, chloramphenicol, and vancomycin on the adapted S. aureus increased. The adapted S. typhimurium was more resistant to penicillin and vancomycin than the non-treated strain. The adapted S. typhimurium and S. aureus lost their antibiotic resistance in non-garlic stress conditions. However, the adapted B. cereus was still resistant to erythromycin and vancomycin, and the adapted E. coli was also resistant to erythromycin. Antibacterial garlic might increase the antibiotic resistance of E. coli, B. cereus, S. aureus, and S. typhimurium and this resistance can continue even without the stress of garlic. Therefore, garlic as a food seasoning could influence the resistance of such pathogens to these antibiotics temporarily or permanently.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.65-68
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• 1994

Vibrio vulnificus에서 lipopolysaccharide(LPS)를 추출하여 지방산 조성을 분석한 후 이 결과를 Escherichia coli LPS와 Salmonella typhimurium LPS의 것들과 비교하였다. Vibrio vulnificus LPS의 주 지방산은 myristic acid(C14:0, 41.37%)이었고 Escherichia coli LPS는 lauric acid(C12:0, 37.03%), Salmonella typhimurium LPS는 capric acid(C10:0, 48.60%)로 서로 달랐으나 이 세가지 지방산이 각 LPS의 주성분이었다(70%이상).

• Korean Journal of Veterinary Service
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• v.38 no.2
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• pp.71-75
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• 2015

Porcine salmonellosis is an economically important disease affecting the global pig industry today. Salmonella (S.) Typhimurium is highly contagious and may rapidly spread within pig populations of herd. To investigate the prevalence of porcine salmonellosis in Jeju, a total of 12,885 blood sera of 96 pig farms from 2009 to 2012 were analyzed by microplate agglutination test. Antibodies to S. Typhimurium were detected in all of pig farms tested in Jeju Province, and the mean of seropositive rate of individual pig was 18.8%. The mean seropositive rate of S. Typhimurium in sows (46.7%) was 7 times higher than that of weaned or growing pigs (6.7%). The lowest seropositive rate (3.0%) was detected in 40 day-old pigs, and this result might be closely associated with the marked decrease of maternal passive immunity. The seropositive rate in winter (42.7%) was higher than in other seasons.

• Journal of Microbiology
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• v.38 no.4
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• pp.270-274
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• 2000

Pathogenic Salmonella typhimurium can invade the intestinal epithelium and cause a wide range of diseases including gastroenteritis and bacteremia in human and animals. To identify the genes involved in the infection, the invasion determinant was obtained from S. typhimurium 82/6915 and was subcloned into pGEM-7Z. A subclone DHl (pSV6235) invaded HEp-2 and Chinese hamster ovary epithelial cells and contained a 4.4 kb fragment of S. typhimurium genomic region. Compared with the host strain E. coli DHl, the subclone DHl (pSV6235) invaded cultured HEp-2 and Chinese hamster ovary cells at least 75- and 68-fold higher, respectively. The invasion rate of E. coli DHl for the cells significantly increased by harbouring the genomic region derived from pathogenic S. typhimurium 82/6915.