• 한국수산과학회지
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• 제49권4호
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• pp.460-466
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• 2016

From 2013 through 2015, we investigated the contamination status and antimicrobial resistance patterns of pathogenic Vibrio parahaemolyticus in commercially valuable seawater and shellfish (Oyster Crassostrea gigas, short-neck clam Venerupis philippinarum, ark shell Scapharca broughtonii and mussel Mytilus galloprovinciallis) from the southern coast of Korea. The detection rate of V. parahaemolyticus was highest in short-neck clams (23.7%), followed by ark shells (19.2%), oysters (15.9%), mussels (13.6%), and seawater (8.6%). The following percentages of PCR assays of shellfish were positive for the thermostable direct hemolysin-related hemolysin gene (trh) : oysters (12.8%), short-neck clams(11.8%), and ark shells (3.4%). Similar assays for the thermostable direct hemolysin gene (tdh) resulted in positive results for short-neck clams (5.9%) and ark shells (3.4%). Antimicrobial resistance was present in 100% of 8 tdh (+) and 2 trh (+) V. parahaemolyticus isolates challenged with ampicillin. However, all pathogenic V. parahaemolyticus were sensitive to 14 other antibiotics. To ensure the safety of shellfish consumption, the continuous monitoring of the prevalence and distribution of virulence factors of V. parahaemolyticus in shellfish farms is needed.

• 한국동물위생학회지
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• 제20권4호
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• pp.359-370
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• 1997

This study was carried out to Investigate the biochemical characteristics, antibiotic susceptibility, serogroups and pili producibility test of enterotoxigenic Escherichia coli(ETEC) isolated from piglets with diarrhea in Kangwon province from March to October 1996. 1. Sixty eight E coli strains were isolated from 72 piglets with diarrhea and the biochemical and cultural reaction were compared with the classification criteria of Edwards and Ewing. 2. The serogroups of 26 isolates were classified as 08 : K87 6(8.8%), O20 : K1O1 4(5.9%), O141 : K85 4(5.9%), 09 : K103 : P987 3(4.4%), O45 : K 2(2.9%) 0139 : K82 2(2.9%), O64 : $K^{-}$2(2.9%), O149 : K91 1(1.5%), O157 : K88ac 1(1.5%) and O115 : $K^{-}$1(1.5%), respectively. 3. In antibiotic susceptibility test, the isolates showed high susceptible to Ak, Eno, Na, Gm, Am and Km, whereas resistance to Tc, Sm and Cf. 4. Sixty one strains(89.7%) of 68 I coli Isolates were resistant to one or more drugs. The isolates resistant to 2 and 3 or more drugs were 60.3% and 19.1%, respectively. Amog the 16 multiple resistant patterns, Sm Tc(11.5% ), Cf Sm Tc(11.5% ), Cf Cp Sm Su Tc(9.8% ) and Cf Cp Sm Su Tc(8.2%) patterns were frequently observed. 5. MRHA of guinea pig erythrocytes was detected in 9 out of 26 OK serotype and 9 out of 42 unidentified serotypes. MRHA titers of serotypes showed from 16 to 32 in O141 : K85 and no titers in O139 : K82. 6. By the GM1 ganglioside ELISA, $\beta$-, $\alpha$-, and $\gamma$-hemolysin producing strains was detected as 36, 6, and 5 from heat labile enterotoxin(LT) of 47 ETEC, respectively. The distribution of LT toxin from 112 isolates was showed $\beta$- hemolysin, 2 isolates $\alpha$-hemolysin and 3 isolates $\gamma$-hemol-ysin from 26 OK serotypes.

• 대한미생물학회지
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• 제18권1호
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• pp.91-98
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• 1983

The effect of subcutanecus injection of Corynebacterium parvum($700{\mu}g$) on cellular and humoral immune responses when given at various time relative to sheep red blood cell(SRBC) sensitization were studied by the evaluation of Arthus, delayed-type hypersensitivity(DTH), rosette forming cell, hemagglutinin and hemolysin reactions. Arthus reactivity(3 hours) developed in control mice and test mice pretreated with C. parvum 8 days prior to intravenous sensitization with SRBC were similar. However, there was slight depression of reactivity when C. parvum was given subcutaneoutly(s.c.) 4 or 2 days prior to SRBC sensitization. Arthus reactivity was significantly depressed when C. parvum was given s.c. either at the same time as, or 2 days later than, antigen. DTH reaction was net depressed significantly when C. parvum was injected 8 or 2 days prior to SRBC sensitization or at the same time as antigen. In contrast DTH was significantly augmented when C. parvum given s.c. 4 days prier to SRBC sensitization. DTH was depressed when C. parvum was given s.c. 2 days after antigen. No significant change occurred in rosette forming percetages of spleen cell when C. parvum was given s.c. 8, 4 or 2 days before SRBC sensitization. In contrast, a significant reduction in percentages of rosette forming cell occurred when C. parvum was given s.c. either at the same time as, or 2 days later than, antigen. Serum hemaggulutinin and hemolysin titers were not significantly affected by subcutaneous injection of C. parvum regardless of time relative to SRBC sensitization. However, mercaptoethanol-resistant hemaggulutinin and hemolysin(IgG) titers were somewhat augmented when C. parvum was given 2 days after antigen. It is concluded from these results that depending on the time and route of inoculation, C. parvum can enhance or depress immune responses in mice, suggesting the time and route of C. parvum inoculation is an important point of concern about clinical use of C. parvum for the treatment of cancer.

• Journal of Microbiology
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• 제44권2호
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• pp.226-232
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• 2006

Swarming has proven to be a good in vitro model for bacterial surface adherence and colonization, and the swarming differentiation of a bacterium has been shown to be coupled with changes in the expression of virulence factors associated with its invasiveness, particularly in the early stages of infection. In this study, we attempted to determine whether the expression of vvhA, which encodes for hemolysin/cytolysin (VvhA), is either upregulated or downregulated during the swarming differentiation of V. vulnificus. The insertional inactivation of vvhA itself exerted no detectable effect on the expression of V. vulnificus swarming motility. However, in our lacZ-fused vvhA transcriptional reporter assay, vvhA expression decreased in swarming V. vulnificus as compared to non-swarming or planktonic V. vulnificus. The reduced expression of vvhA in swarming V. vulnificus increased as a result of the deletional inactivation of luxS, a gene associated with quorum sensing. These results show that vvhA expression in swarming V. vulnificus is downregulated via the activity of the LuxS quorum-sensing system, suggesting that VvhA performs no essential role in the invasiveness of V. vulnificus via the adherence to and colonization on the body surfaces required in the early stages of the infection. However, VvhA may playa significant role in the pathophysiological deterioration occurring after swarming V. vulnificus is differentiated into planktonic V. vulnificus.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1200-1209
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• 2021

Sepsis is an acute inflammatory response that leads to life-threatening complications if not quickly and adequately treated. Cytolysin, hemolysin, and pneumolysin are toxins produced by gram-positive bacteria and are responsible for resistance to antimicrobial drugs, cause virulence and lead to sepsis. This work assessed the effects of aloe-emodin (AE) and photodynamic therapy (PDT) on sepsis-associated gram-positive bacterial toxins. Standard and antibiotic-resistant Enterococcus faecalis, Staphylococcus aureus, and Streptococcus pneumonia bacterial strains were cultured in the dark with varying AE concentrations and later irradiated with 72 J/cm^-2 light. Colony and biofilm formation was determined. CCK-8, Griess reagent reaction, and ELISA assays were done on bacteria-infected RAW264.7 cells to determine the cell viability, NO, and IL-1β and IL-6 pro-inflammatory cytokines responses, respectively. Hemolysis and western blot assays were done to determine the effect of treatment on hemolysis activity and sepsis-associated toxins expressions. AE-mediated PDT reduced bacterial survival in a dose-dependent manner with 32 ㎍/ml of AE almost eliminating their survival. Cell proliferation, NO, IL-1β, and IL-6 cytokines production were also significantly downregulated. Further, the hemolytic activities and expressions of cytolysin, hemolysin, and pneumolysin were significantly reduced following AE-mediated PDT. In conclusion, combined use of AE and light (435 ± 10 nm) inactivates MRSA, S. aureus (ATCC 29213), S. pneumoniae (ATCC 49619), MDR-S. pneumoniae, E. faecalis (ATCC 29212), and VRE (ATCC 51299) in an AE-dose dependent manner. AE and light are also effective in reducing biofilm formations, suppressing pro-inflammatory cytokines, hemolytic activities, and inhibiting the expressions of toxins that cause sepsis.

• Journal of Microbiology and Biotechnology
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• 제22권8호
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• pp.1170-1176
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• 2012

In this study, we aimed to evaluate the effect of ${\alpha}$-cyperone on S. aureus. We used a hemolysin test to examine the hemolytic activity in supernatants of S. aureus cultured with increasing concentrations of ${\alpha}$-cyperone. In addition, we evaluated the production of ${\alpha}$-hemolysin (Hla) by Western blotting. Real-time RT-PCR was performed to test the expression of hla (the gene encoding Hla) and agr (accessory gene regulator). Furthermore, we investigated the protective effect of ${\alpha}$-cyperone on Hla-induced injury of A549 lung cells by live/dead and cytotoxicity assays. We showed that in the presence of subinhibitory concentrations of ${\alpha}$-cyperone, Hla production was markedly inhibited. Moreover, ${\alpha}$-cyperone protected lung cells from Hla-induced injury. These findings indicate that ${\alpha}$-cyperone is a promising inhibitor of Hla production by S. aureus and protects lung cells from this bacterium. Thus, ${\alpha}$-cyperone may provide the basis for a new strategy to combat S. aureus pneumonia.

• 한국수산과학회지
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• 제28권4호
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• pp.443-450
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• 1995

리스테리아 증세로 의심되는 환자의 혈액으로부터 분리한 균은 저온에서의 운동성 시험, 용혈능 검정시험, 당 이용성, CAMP 시험의 결과 전형적인 L. monocytogenes의 특성을 보여 L. monocytogenes YM-7로 동정하고 명명하였다. L. monocytogenes YM-7의 세균학적 특성과 이 균이 생산하는 용혈독소의 이화학적 특성은 다음과 같다. L. monocytogenes YM-7 균주는 Gram양성 간균으로, 운동성 측정 결과 반고체 배지에서 우산 모양의 층이 생겼고, 최적증식조건은 $37^{\circ}C$, 식염 농도 $0^{\circ}C$, pH 8.0이었고, 이 균의 생육 가능범위는 $8-40^{\circ}C$, 식염 농도 $0.7\%$, pH 5.0-10.0였다. L. monocytogenes YM-7 균주가 생산하는 용혈독소는균 생육곡선의 정지기 부근에서 최대 활성을 나타내었다. 이 용혈독소는 비교적 열에 불안정하였으나, $37^{\circ}C$에서 180분 후에도 용혈활성이 남아 있었다. 그리고 용혈독소는 pH 6.0-8.0에서 안정하였으나 그 외의 pH 영역에서는 매우 불안정 하였다

• 대한미생물학회지
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• 제35권3호
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• pp.251-261
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• 2000

V. vulnificus is an estuarine bacterium which causes septicemia and shock in susceptible patients. The organism produces a hemolytic cytolysin (VvH), which has a membrane damaging effect on erythrocytes. To clarify the mechanisms by which VvH might contribute to virulence, we examined its effect on macrophages. When mouse peritoneal macrophages were harvested and co-cultured with hemolysin-positive V. vulnificus strains (100 bacteria/cell), about 60% of the macrophages were killed; macrophages were not killed when co-cultured V. vulnificus strain CVD 707, a VvH-negative deletion mutant. Exposure of macrophages to filtered culture supernatants (2.5 HU/ml) and purified VvH (3 HU/ml) resulted in an increase in dead cells (80 and 90%, respectively), as determined by the trypan blue dye exclusion method and LDH release from macrophages was also increased (70 and 65.5%, respectively). The cytotoxic effect of VvH on macrophages was both the dose- and time-dependent. The VvH caused damage to the macrophage membrane and was blocked significantly by preincubation with cholesterol (p<0.01). Fetal bovine serum showed remarkable inhibition of VvH synthesis by V. vulnificus and inhibited VvH activity in culture supernatant. Cell viability was increased by 35% (p<0.01) and LDH release decreased by 28% (p<0.01) when macrophages were incubated with V. vulnificus (100 bacterial cell) in DMEM-10% FBS for 2 hr. Bacterial clearance activity of mice against V. vulnificus CVD 707 was decreased by pretreatment with 10 HU of VvH. This result suggests that the VvH can impair the membrane of macrophages and may playa role in the pathogenesis of V. vulnificus septicemia.

• 미생물학회지
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• 제35권3호
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• pp.248-252
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• 1999

한국의 환경에서 분리된 47주와 환자 혈액에서 분리된 18주의 Vibrio cholerae serovar non-O1 및 non-O139를 대상으로 하여 콜레라 독소, 콜레라 독소 유전자, 용혈소, 그리고 혈구응집소 등이 병독인자 분포를 알아보았다. 시험된 65균주 중 용혈소만 생산하는 균은 29균주였고, 용혈소와 혈구 응집소를 생산하는 것은 65균주 중 36 균주였다. 용혈소, 콜레라 독소 및 유전자, 그리고 혈구응집소 모두를 가지고 있는 것은 환경에서 분리된 O37형 한 균주이었다. 한편 첨가한 당농도에 따른 혈구응집소 억제시험에서, 1% 이하의 mannose 와 galactose에서 응짐이 억제된 것은 환경분리균주 47 균주 중에서 26균주로 내혈구응집소나 외혈구응집소가 비슷한 비율로 분포하였고, 반면 환자분리균주는 18균주 중에서 5균주가 외혈구응집소의 비율이 훨씬 높았다. 따라서 V.cholerae non-1 및 non-O139의 용혈소가 주독소로 병독인자 분포는 다양하게 나타났다. 콜레라 독소가 유일한 병독이자라고 인식하기는 어려웠고 여러 가지 인자들이 복합적으로 작용될 것으로 생각되었다. 특히 환경분리주 O37 형에서 콜레라 독소 생성윤이 발견된 것을 향후 역학적인 측면에서 많은 연구가 되어야 할 것으로 사료되었다.

• 미생물학회지
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• 제52권3호
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• pp.260-268
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• 2016

본 연구의 목적은 시중에 판매되고 있는 쌈장에서 용혈성을 가지는 Bacillus cereus MH-2를 분리하여, EGCG 노출에 따른 MH-2 균주의 세포 반응과 프로테옴 분석을 위해 수행되었다. 다양한 농도의 EGCG에 노출된 MH-2 균주는 노출시간이 증가함에 따라 생존률은 점차 감소함을 보였다. MH-2 균주의 alginate 생성량은 EGCG의 농도가 증가함에 따라 감소하였으며, 특정 EGCG 농도에서 노출시간이 진행됨에 따라 그 생성량은 증가하는 것으로 나타났다. SDS-PAGE 및 anti-DnaK와 anti-GroEL의 단일항체를 이용한 Western blot 통한 분석으로, 두 가지 스트레스 충격단백질인 70 kDa의 DnaK와 60 kDa의 GroEL의 발현은 대수생장기의 배양에서 EGCG의 농도에 비례하여 감소하는 것을 확인하였다. EGCG에 노출된 세균의 세포 외부형태 변화를 주사전자현미경을 이용하여 관찰한 결과, 세포 표면의 돌출부 생성과 함께 세포의 뭉그러짐이 관찰되었다. EGCG에 노출된 Bacillus cereus MH-2 배양의 수용성 단백질 부분에 대한 2-DE에서 20개의 단백질 스팟이 EGCG 노출에 의해 크게 변화하는 것이 확인되었다. 장독소(hemolysin BL lytic component L1, hemolysin BL-binding protein), chaperon (DnaK, GroEL), 세포방어요소(peptidase M4 family proteins), 에너지 및 물질대사 등에 수반되는 이들 단백질은 MALDI-TOF를 사용한 peptide mass fingerprinting에 의해 동정되었다. 이들 결과는 B. cereus MH-2에 대한 EGCG-유도 스트레스와 세포독성의 기작을 이해하는데 중요한 단서를 제공할 것이다.