• 한국가축위생학회:학술대회논문집
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• 한국가축위생학회 2000년도 제23차 학술대회
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• pp.180-181
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• 2000

• 한국환경보건학회지
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• 제39권5호
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• pp.465-473
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• 2013

Objectives: This study was undertaken to analyze Staphylococcus aureus from cultivation environments for agricultural products and to confirm antibiotic resistance and enterotoxin genes for the isolated S. aureus. Methods: A total of 648 samples were collected from apple, peach, ginseng and balloon flower farms. S. aureus was isolated from soil, agricultural water, personal hygiene elements (hands, gloves and clothes) and work utensils (boxes). Results: S. aureus was detected in a total of 25 samples and 72 strains were isolated. The resistance rate of the isolated S. aureus strains was confirmed at 33.3%, with 24 resistant strains among the total of 72. Fourteen different patterns types were found, and three pattern types (NV, OX, VA) were confirmed most frequently. As result of the detection of enterotoxin gene type, four gene types (sea: 1, sed: 4, seg: all isolated S. aureus, sei: all isolated S. aureus) were analyzed among a total of nine types. Conclusions: This study demonstrates that personal hygiene techniques should be properly managed, such as washing and sterilization before or after work, because agricultural contamination by S. aureus frequently developed through improper management.

• Journal of Microbiology and Biotechnology
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• 제25권12호
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• pp.2043-2048
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• 2015

Bacillus thuringiensis microbial insecticide products have been applied worldwide. Although a few cases of B. thuringiensis foodborne illness have been reported, little is known about the toxigenic properties of B. thuringiensis isolates. The aims of this study were to estimate the pathogenic potential of B. thuringiensis selected from microbial insecticide products, based on its possession of toxin genes and production of enterotoxins. Fifty-two B. thuringiensis strains selected from four kinds of microbial insecticide products were analyzed. PCR assay for detection of toxin genes and immunoassay for detection of enterotoxins were performed. The hemolysin BL complex as a major enterotoxin was produced by 17 (32.7%), whereas the non-hemolytic enterotoxin complex was detected in 1 (1.9%) of 52 B. thuringiensis strains. However, cytK, entFM, and ces genes were not detected in any of the tested B. thuringiensis strains. The potential risk of food poisoning by B. thuringiensis along with concerns over B. thuringiensis microbial insecticide products has gained attention recently. Thus, microbial insecticide products based on B. thuringiensis should be carefully controlled.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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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.

• 대한임상검사과학회지
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• 제40권1호
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• pp.48-54
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• 2008

Multiplex-PCR을 이용하여 대구와 경상북도 내의 다양한 입원 환자들로부터 분리된 187주의 MRSA 균주를 재료로 9가지 종류의 내독소(sea~see, seg~sej ), 3종류의 병독소(eta, etb, tst ) 그리고 내부 양성 지표로써 16S rRNA와 MecA 유전자를 검출하였다. S. aureus 균주에서 새로운 형태의 내독소 유전자(seg~sej)의 빈도가 65.9%로 매우 높게 잠복하고 있었으며, 고전적 형태의 내독소 유전자(sea~see)도 47.8%로 선행 연구에서 검출된 것만큼 높게 잠복하고 있었다. 새로운 형태의 내독소 중 쌍을 이룬 형태(즉, sec+seg+sei, seg+sei)는 많이 검출된 반면 단일 형태의 내독소(즉, seg, seh, sei, sej)는 거의 검출되지 않았거나 없었으며, 쌍을 이룬 내독소 유전자를 가진 S. aureus는 잠재적으로 보다 더 독성균주가 될 것으로 판단된다. 더 나아가 S. aureus 균주들 사이의 높은 보유율을 보이는 seg와 sei 사이의 체계적인 관련성은 staphylococcal enterotoxin들 사이에 중요한 계통발생적 연계가 있을 수 있다는 것은 암시한다.

• 한국식품조리과학회지
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• 제28권5호
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• pp.599-604
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• 2012

In this study, the prevalence of microbiological hazard on water purifiers at lunchroom in child care center was investigated. A total of 49 water purifiers and their purified cold water were sampled to test about the total aerobic bacteria, coliform bacteria, Bacillus cereus, Staphylococcus aureus, and Salmonella spp. Total aerobic bacteria was detected over 2.0 log CFU/mL in 6 out of 49 purified cold water (12.2%), ranged from 2.0 to 2.4 log CFU/mL, and the average number of total aerobic bacteria was showed to be 3.3 log CFU/drain spout. The drain spout turned out to be a major contaminant in water purifier and needs to be improved. Coliform bacteria were also detected in 7 out of 49 cold faucets (14.3%) and 7 out of 49 drain spouts (14.3%), but not detected in purified cold water. All samples were not contaminated with the pathogens tested in this study, except for B. cereus, which was contaminated on 2 out of 49 cold faucets (4.1%) and 4 out of 49 drain spouts (8.2%). All of B. cereus isolates produced enterotoxin, such as heamolysin BL enterotoxin (HBL) or non-heamolytic enterotoxin (NHE). The HBL was detected in 5 out of 6 B. cereus isolates (83.3%), including B. cereus PCF-11 and B. cereus PDS-30 isolate only produced NHE (16.7%). These results showed that the sanitary conditions of cold faucets and drain spouts should be improved promptly.

• 대한미생물학회지
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• 제22권4호
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• pp.377-392
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• 1987

Monoclonal antibody to the Escherichia coli heat-stable enterotoxin(ST) was produced to develop a rapid and convenient diagnostic method to the ST. The toxin was purified from culture supernatant of enterotoxigenic E. coli O148H28($ST^+/LT^+$) and conjugated to bovine serum albumin(BSA). The ST-BSA conjugate was used to immunize BALB/c mice and the immune spleen cells from these mice were fused with $P3{\times}63$ Ag8.V653 plasmacytoma cells. Hybridomas were screened by ELISA and positive hybridomas were cloned by limiting dilution. Finally, one stable clone (AS36) specific to ST was selected for further growth and characterization. Antibody titers of culture supernatant and ascitic fluid from BALB/c mice were 1:1,024 and 1:20,480 respectively in ELISA. The isotype and subclass of monoclonal antibody was IgG1 in sandwich ELISA. To test the neutralizing effect of monoclonal antibody on toxin activity of ST, mixture of ascitic fluid and ST was assayed by infant mouse assay and this monoclonel antibody was proved to be a neutralizing antibody. The titer of ascitic fluid which completely neutralized biological activity of 4 units of ST was 1:4. Purified ST was quantitatively measured by competitive ELISA and minimum amount of ST detectable by this assay was 250pg, which was an amount six-fold smaller than that detectable by infant mouse assay. Four reference strains of enterotoxigenic E. coli from WHO were detected by competitive ELISA and highly specific, sensitive and reproducible result was obtained.

• 미생물학회지
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• 제9권2호
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• pp.86-93
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• 1971

위생환경이 좋지 못하고 보건사업의 혜택이 원활치 못한 지역의 소아 및 국민학동에게서 분리한 장내 세균 중 이열성 장내 독소생성 대장균주의 분포를 배양된 부신암 세포를 이용하여 살펴보았다. 이 열성 장내독소의 존재아래 부신암 세포는 세포의 원형화 및 seroid 생성력의 항진을 보이기에 이 두 성질에 기처를 두어 독소생선균주를 감별하였다. 실험의 결과 조사대상자의 약 10%에 해당하는 균주들이 독소 생성 균주로 밝혀졌다. 분리한 균주의 화학요법제에 대한 감수성 내지 내성도를 측정하였는데 특히 주목할 것은 이열성 장내독소 균주들의 대부분이 gentamycin(10mg)과 nalidixic acid(5mg)에 감수성이 있는데 비해, colistin(10mg), novobiocin(30mg), sulfa drug(50mg)에는 내성을 나타냈으며, 장내 질환에 널리 쓰이는 chloramp-henicol(10mg)에 대해서는 균에 따라 감수성 또는 내성을 보인데 있다. 이상의 조사로 우리나라 정상아동이 상당의 이열성 장내독소 생성균주를 보유하고 있음을 알수 있다. 이를 균주중 몇개는 장내질환 치료제로 널리 사용하는 항생제에 대해 내성을 지니고 있음을 볼 수 있었다.

• 미생물학회지
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• 제45권4호
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• pp.425-429
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• 2009

Bacillus cereus 설사독소 전사조절유전자인 plcR 및 papR의 특이적 프라이머 쌍을 사용한 PCR로 설사 독소유전자 함유 B. cereus 균의 검출 가능성을 조사하였다. 적어도 한 종류 이상의 독소유전자들(hblACD, nheABC, cytK)을 함유한 96균주의 B. cereus를 대상으로 plcR-papR 유전자에 특이적인 프라이머들을 이용하여 PCR을 한 결과 모두 양성을 나타냈다. 그러나 독소 유전자를 함유하지 않은 48균주의 Bacillus들로 같은 분석을 한 결과 모두 음성을 보였다. PCR에 의한 plcR-papR 유전자 검출법은 설사독소 유전자를 함유한 B. cereus를 확인하는데 간편하면서도 정확한 결과를 제공하였다.

• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.598-606
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• 2003

Salmonella encodes an enterotoxin (Stn) which possesses biological activity similar to the cholera toxin. Stn contributes significantly to the overall virulence of S. typhimurium in a murine model. The production of Stn is enhanced in a high-osmolarity medium and by contact with epithelial cells. In the present study, the in vitro and in vivo transcriptional regulations of the sin promoter revealed two promoters, P1 and P2. The P1 promoter identified by a primer extension analysis of stn mRNA exhibited a switching mechanism in vivo. Depending on the growth stage, transcription was initiated from different start sites termed $P1_S\;and\;P1_E$. $P1_S$, recognized by RNA polymerase containing ${\sigma}^S(E{\sigma}^S),\;and\;P1_E$, recognized by $E{\sigma}^70$, were activated during the stationary and exponential phases, respectively, while $P1_S\;and\;P1_E$ were both negatively regulated by CRPㆍcAMP and H-NS. Results revealed that $P1_S$ was the responsible promoter activated under a high osmolarity and low pH. The P2 promoter was identified 45 nucleotides downstream from $P1_E$ and negatively controlled by CRPㆍcAMP in vitro. No P2 activity was detected in vivo. The regulation of stn expression monitored using a Pstn::egfp fusion indicated that $E{\sigma}^S$ was required for the induction of stn and various factors were involved in stn regulation inside animal cells.