ABSTRACT
Objective To analyze the effects of Clostridium difficile toxin B (TcdB) on the prolif-eration and apoptosis of colon cancer cell line SW480 and the possible mechanisms related to cell apoptosis. Methods SW480 cells were treated with different concentrations of TcdB. Cell proliferation was detected by MTT assay. Cell apoptosis and mitochondrial membrane potential were measured with flow cytometry. Re-sults TcdB significantly inhibited the proliferation of SW480 cells in a time-concentration dependent man-ner and the inhibition rate reached 46. 36％ at 48 h. Flow cytometry results showed that TcdB could induce the apoptosis of SW480 cells in a time-concentration dependent manner and a 20. 83％ apoptosis rate was in-duced by 800 ng/ml of TcdB at48 h. Conclusions TcdB could inhibit the proliferation and induce the ap-optosis of colon cancer SW480 cells, and the possible mechanisms might be relate to the initiation of mito-chondrial apoptosis pathway.
ABSTRACT
Objective@#To analyze the effects of Clostridium difficile toxin B (TcdB) on the proliferation and apoptosis of colon cancer cell line SW480 and the possible mechanisms related to cell apoptosis.@*Methods@#SW480 cells were treated with different concentrations of TcdB. Cell proliferation was detected by MTT assay. Cell apoptosis and mitochondrial membrane potential were measured with flow cytometry.@*Results@#TcdB significantly inhibited the proliferation of SW480 cells in a time-concentration dependent manner and the inhibition rate reached 46.36% at 48 h. Flow cytometry results showed that TcdB could induce the apoptosis of SW480 cells in a time-concentration dependent manner and a 20.83% apoptosis rate was induced by 800 ng/ml of TcdB at 48 h.@*Conclusions@#TcdB could inhibit the proliferation and induce the apoptosis of colon cancer SW480 cells, and the possible mechanisms might be relate to the initiation of mitochondrial apoptosis pathway.
ABSTRACT
BACKGROUND: Increasing rates of Clostridium difficile infection (CDI) have been reported mainly in Europe and North America; however, only limited reports have originated in Korea. The current epidemiology of CDI in the community could help to understand the outpatient healthcare environment and to extend infection control measures to outpatient settings. METHODS: C. difficile isolates in NHIS Ilsan Hospital from 2012 to 2014 were included in this study. Clinical characteristics, acquisition types, and previous antimicrobial therapy were obtained via Electronic Medical Records. C. difficile culture was performed only in unformed stool. Toxin was positive by enzyme-linked fluorescent immunoassay (ELFA) in 247 specimens. In addition, toxin B and binary toxin gene were detected by PCR in 57 specimens. CDI was defined by toxigenic C. difficile isolation in unformed stool. RESULTS: In the previous 3 years, 251 unduplicated C. difficile cases have been detected; 168 healthcare facility- associated hospital onset (HCFA-HO), 45 healthcare facility-associated community onset (HCFA-CO), and 38 community-associated (CA). Toxin positive rates by ELFA for toxin A&B were HCFA-HO 50.6% (84/166), HCFA-CO 41.9% (18/43), and CA 42.1% (16/38). Toxin positive rate by PCR for tcdB were HCFA-HO 62.9% (22/35), HCFA-CO 69.2% (9/13), and CA 100% (9/9). No binary toxin (cdtA/cdtB) was detected in 57 cases. CONCLUSION: Community-associated CDI may be underestimated in Goyang province, Korea, especially by commonly used ELFA toxin assay. The spread of community-associated CDI should be recognized as an increasing burden of public health.
Subject(s)
Humans , Clostridioides difficile , Clostridium , Community-Acquired Infections , Delivery of Health Care , Electronic Health Records , Epidemiology , Europe , Immunoassay , Infection Control , Korea , North America , Outpatients , Polymerase Chain Reaction , Public HealthABSTRACT
BACKGROUND: Toxin immunoassay is widely used for rapid diagnosis of Clostridium difficile-associated diarrhea. The aim of this study was to evaluate the performance of Tox A/B Quik Chek test (TECHLAB, Blacksburg, VA, USA) compared to toxigenic culture. METHODS: From September 2006 to August 2007, 959 stools were examined by Tox A/B Quik Chek test and toxigenic culture (C. difficile culture plus tcdB PCR using colonies obtained from culture). RESULTS: Compared to the results of toxigenic culture, the sensitivity and specificity of Tox A/B Quik Chek test were 47.5% and 97.5%, respectively. CONCLUSION: The sensitivity of Tox A/B Quik Chek test was not high, but the specificity was high. Although Tox A/B Quik Chek test alone is not sufficient to diagnose Clostridium difficile-associated diarrhea, it may aid rapid diagnosis, early treatment and prevention of nosocomial spread of the infection, if supplemented by C. difficile culture or tissue culture cytotoxin assay.