• Journal of Life Science
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• v.10 no.4
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• pp.380-387
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• 2000

Recently Vibrio sp. are the most frequently isolated microorganism, which causing food poisoning. We investigated the detection of toxin genes and effect of chitosan to toxin genes with PCR. Thirty strains of Vibrio sp. were isolated from sea water and sea products through biological and biochemical tests. Out of 30 strains, 8 were identified as V. parahemolyticus, 7 as V. mimcus, 6 as V. damsela, 5 as V. vulnificus, 4 as V. alginoyticus. In detection of ctx, tdh, and t고 as food poisoning-causing toxin genes, ctx from 7 strains, trh from 4 strains and tdh from 6 strains were detected. Among toxin genes detected strains, we selected V. vulnificus-2 V. damsela-1 and V. parahemolyticus-7. As adding chitosan solution to PCR product of 3 strains, the amplified DNA bands were not detected over 450$\mu\textrm{g}$/$m\ell$ concentrantion of chitosan. Over the result, chitosan is thought to influence the detection of toxin gene.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.202-209
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• 2016

This study is aimed to determine the correlation between the toxin gene types and antibiotic resistance from MRSA (methicillin-resistant Staphylococcus aureus). Fifty-two strains of MRSA, between January 2014, and December 2014, were isolated from clinical specimens obtained from 2,664 cases in the intensive care unit of a hospital in Suncheon, Jeonnam, Korea. Genes encoding mecA, enterotoxin (SE), toxic shock syndrome toxin-1 (TSST-1), exfoliative toxin (ET), and Panton-Valentine leukocidin (PVL) were detected by multiplex PCR-mediated amplification using specific primers. Toxin genes (seg and sei) were present in 40 strains (76.9%), followed by tst in 34 strains (65.4%). Other genes (eta, etb, sea, sed, see, seh, sej, and pvl) were not detected. Forty strains (76.9%) of MRSA had 2 or more toxin genes simultaneously; 5 coexistent toxin-genes (seb, sec, seg, sei, tst) were the most common in 28 strains (53.8%), and 6 strains (11.5%) had seg and sei genes. The coexistence of genes were 72.5~100%, showing a high correlation among genes (seb, sec, seg, sei and tst). As strains (seb, sec, tst) that had particular toxin genes (seb, sec, seg, sei, tst) in multiple showed 100% resistance to ciprofloxacin, clindamycin, erythromycin, we were able to find that seb, sec, and tst genes have a close relationship to the aforementioned antibiotics. It showed a higher resistance to ciprofloxacin, clindamycin, erythromycin, and tetracycline compared with strains that had toxin genes independent from multiple toxin genes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3315-3322
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• 2015

Staphylococcus aureus is the major causative organism of nasocomial infection being the important pathogen in the clinic. Appearance of staphylococcus aureus resistant to methicillin (MRSA) is becoming a big problem in clinics and dynamics all over the world acquiring antibiotic resistance with virulence factors as its feature differentiated from other pathogenic bacteria fast. This research intended to compare and analyze the correlation of antibiotics resistance between strains with toxin genes and distribution of toxin genes of MRSA 101 strains acquired from clinical specimen in one general hospital (enterotoxin(se), toxic shock syndrome toxin-1(tst), exfoliative toxin(et), Panton Valentine leukocidin(pvl)). seg gene, isolated the most among toxin genes, was detected in 59 strains (58.4%) and more than two toxin genes were detected in 70 strains (69.3%). As a combination possessing toxin genes, it was detected in 19 strains (18.8%) as seb, sec, seg, sei, tst and the second frequent combination was sec, seg, sei shown in 11 strains (10.9%). 19 strains (18.8%) with combinations of toxin genes same with seb, sec, seg, sei, tst had 100% resistance Ampicillin, Benzylpenicillin, Ciprofloxacin, Clindamycin, Gentamicin, Erythromycin, Telithromycin, Tetracycline antibiotics. Strains with many toxin genes showed high correlation of antibiotic resistance. Afterwards, effective therapy and thorough infection management should be preceded not to spread the resistance of MRSA strain.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.425-429
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• 2003

Staphylococcus aureus is a major pathogen for cattle, causing various forms of subclinical and clinical mastitis and could be a causative agent of food poisoning, it produces various superantigenic exotoxins which have a great public health significance. A total of 72 S. aureus clinical isolates from dairy farms located in Kyunggi Province Korea were examined for the species identification by biochemical method, and for the detection of $\beta$-lactamase, enterotoxin and other exotoxins genes by PCR. The results of species identification by biochemical method agreed with those of PCR done with species specific primer STA-AU. $\beta$-lactamase is an enzyme closely associated with the resistance to antibiotic penicillin, which is an important means of treatment of mastitis, all the isolates were positive for the presence of genes encoding $\beta$-lactamase, which were reproduced in penicillin susceptibility disc assay. Six types of toxin genes, Staphylococcal enterotoxin (SE)A, SEB, SEC, SEE, toxic shock syndrome toxin (TSST-1) and exfoliative toxin A (ET A) were detected in 72 isolates by PCR associated genotypic method in this study, none of the isolates carried the genes for enterotoxin D (SED) and exfoliative toxin B (ETB). The occurrence rate of exotoxin genes rated as 12.5%, and the precision of the PCR identification results has been confirmed using the reference strains.

• Journal of Environmental Health Sciences
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• v.42 no.4
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• pp.255-265
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• 2016

Objectives: Mobile phones have become one of the most essential accessories in daily life. However, they may act as reservoir of infectious pathogens if they are used without hygienic practices in their handling. Therefore, this study aimed to isolate food-borne pathogens from mobile phones and investigate the characteristics of toxin genes and antibiotic susceptibility patterns. Methods: A total of 146 mobile phones were collected from 83 middle- and 63 high-school students in Busan. The surfaces of the mobile phones were aseptically swabbed. Results: Among the food-borne pathogens, Staphylococcus aureus, Bacillus cereus and Escherichia coli were detected in 26 (17.8%), 20 (13.7%) and four (2.7%) samples, respectively. There were no statistically significant differences according to school level, gender or phone type. None of four E. coli strains had pathogenic toxic genes. All of the B. cereus strains carried at least three different toxin genes among the nine enterotoxin and emetic toxin genes. Three out of 20 B. cereus strains (15%) possessed emetic toxin genes, which are rarely detected in food-poisoning cases in Korea. Among the 26 strains of S. aureus, the detection rate of staphylococcal enterotoxin genes, toxic shock syndrome toxin (tsst) and factors essential for methicillin resistance (femA) were 84.6%, 7.7% and 100%, respectively. In the antibiotic susceptibility test, there was no methicillin-resistant S. aureus (MRSA) or vancomycin-resistant S. aureus (VRSA). Conclusion: The results show that students' mobile phones in Busan were contaminated by food-borne pathogens which carried various toxic genes. Therefore, regular phone disinfection and hand hygiene is important in order to reduce cross-contamination.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.826-832
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• 2023

Clostridium perfringens causes diarrhea and other diseases in humans and animals. We investigated the prevalence, toxin gene profiles, and antimicrobial resistance of C. perfringens isolated from commercial jeotgal sample. C. perfringens was isolated from 11 of 22 commercial jeotgals. All C. perfringens strains were positive for the alpha toxin gene, but not for the beta, epsilon, iota, CPE or NetB toxin genes; therefore, all strains were identified as type A C. perfringens. However, the beta2 toxin gene was identified in 54.5% of isolates. Disk diffusion susceptibility tests showed that most isolates were resistant to kanamycin (90.9%), nalidixic acid (72.7%), oxacillin (54.5%), erythromycin (27.3%), ciprofloxacin (9.1%) and clindamycin (9.1%). However, all strains were susceptible to 14 other antimicrobial including amoxicillin, ampicillin, and chloramphenicol. The average minimum inhibitory concentrations against C. perfringens of clindamycin, kanamycin, and nalidixic acid were 128.0, 128.0, and 54.0 ㎍/mL, respectively. These results provide new insight into the necessity for sanitation of commercial jeotgal, and provide evidence to help reduce the risk of contamination with antimicrobial-resistant bacteria.

• BMB Reports
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• v.38 no.4
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• pp.386-390
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• 2005

Based on the reported cDNA sequences of $BmK{\alpha}Txs$, the genes encoding toxin $BmK{\alpha}Tx11$ and $BmK{\alpha}Tx15$ were amplified by PCR from the Chinese scorpion Buthus martensii Karsch genomic DNA employing synthetic oligonucleotides. Sequences analysis of nucleotide showed that an intron about 500 bp length interrupts signal peptide coding regions of $BmK{\alpha}Tx11$ and $BmK{\alpha}Tx15$. Using cDNA sequence of $BmK{\alpha}Tx11$ as probe, southern hybridization of BmK genome total DNA was performed. The result indicates that $BmK{\alpha}Tx11$ is multicopy genes or belongs to multiple gene family with high homology genes. The similarity of $BmK{\alpha}$-toxin gene sequences and southern hybridization revealed the evolution trace of $BmK{\alpha}$-toxins: $BmK{\alpha}$-toxin genes evolve from a common progenitor, and the genes diversity is associated with a process of locus duplication and gene divergence.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.361-367
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• 2010

Bacterial contamination of cooked rice was analyzed to evaluate the microbial safety. Thirty raw rice samples were collected in Korea and cooked in an electric rice cooker. Mesophilic aerobe, food-poisoning Bacillus cereus group, and their toxin genes were determined on cooked rice. The percentage of total mesophilic aerobe based on 1-3 log CFU/g was 27% among the samples. Bacillus spp. in MYP selective medium was similar to the number of mesophilic aerobe, whileas Bacillus spp. was detected in most samples after enrichment. Thirty-seven isolates from 30 cooked rices were identified as B. thuringiensis, B. cereus, B. valismortis, B. pumilus, B. coagulans, B. licheniformis, Geobacillus stearothermophilus, and Brevibacillus laterosporus. Twenty isolates (54%), more than half of the isolates, were B. thuringiensis while nine (27%) were identified as B. cereus. All B. thuringiensis isolates possessed non-hemolytic toxin genes and interestingly, seven B. cereus among nine isolates possessed emetic toxin genes. More B. thuringiensis was present on the cooked rice than B. cereus and most B. cereus possessed emetic toxin genes rather than diarrheal toxin genes. Therefore, food-borne outbreak due to B.cereus on the cooked rice kept at room temperature might be examples of emetic food-poisoning.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1449-1456
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• 2017

The prevalence and toxin characteristics of Bacillus thuringiensis isolated from 39 organic vegetables were investigated. B. thuringiensis was detected in 30 out of the 39 organic vegetables (76.9%) with a mean value of 2.60 log CFU/g. Twenty-five out of the 30 B. thuringiensis isolates (83.3%) showed insecticidal toxicity against Spodoptera exigua. The hblCDA, nheABC, and entFM genes were found to be the major toxin genes, but the ces gene was not detected in any of the tested B. thuringiensis isolates. The hemolysin BL enterotoxin was detected in all 30 B. thuringiensis isolates (100%). The non-hemolytic enterotoxin complex was found in 27 out of 30 B. thuringiensis isolates (90.0%). The B. thuringiensis tested in this study had similar toxin gene characteristics to B. cereus, which possessed more than one toxin gene. B. thuringiensis could have the potential risk of foodborne illness based on the toxin genes and toxin-producing ability.

• Korean Journal of Veterinary Service
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• v.39 no.2
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• pp.87-92
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• 2016

Porcine edema disease (ED) is a communicable disease of pigs caused by infection with Shiga toxin (Stx)-producing Escherichia coli (STEC) which expresses F18 fimbriae and/or Stx type 2e (Stx2e). While STEC causes a severe illness including hemorrhagic colitis and hemolytic-uremic syndrome in humans, it induces damage to the vascular endothelium, which results in edema, hemorrhage, and microthrombosis, leading in high mortality in pigs. In the present study, we cultured Stx2e-producing E. coli field isolates from conventional pig farms that experienced sudden deaths previously with symptoms similar to porcine edema disease, which were further investigated with Shiga toxin profiles. A total of 43 strains were identified from the collected samples by F18 or Stx2e specific PCR. Based on the PCR, 42 isolates out of 43 isolates were proved to carry one of F18 or Stx2e genes and 14 isolates to carry both F18 and Stx2e genes. All of the 30 isolates that harbored Stx2e gene induced the cytopathic effect (CPE) in vero cells and especially, the isolate 150229 produced the highest level of Shiga toxin. Therefore, we identified the virulence genes (F18 and Stx2e) and demonstrated Shiga toxin-producing abilities from porcine edema disease causing E. coli filed isolates. These results suggested that one of the isolates could be a vaccine antigen candidate against STEC through further investigating to elicit an immune response.