Effect of Acinetobacter baumannii ATCC 19606 on macrophage RAW 264.7

• Main Authors: Lin Chiung-Hui, 林瓊慧
• Other Authors: Liou Ming-Li
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/uasxq7

碩士 === 元培科技大學 === 醫學檢驗生物技術研究所 === 97 === Acinetobacter baumannii belonged to nonfermentative Gram-negative and bacilli. This organism always deposits in moist environment of hospitals and was caused opportunistic infections such as ventilator-associated pneumonia, urinary tract and wound infections. Up to now, most of the studies have focused on the characteristics and mechanisms of antimicrobial resistance in A. baumannii, the cytotoxicity of the organism remains unclear. The aim of the study was to investigate the effect of mouse macrophage RAW 264.7 infected with A. baumannii ATCC 19606. The time course study showed that cell viability was declined to 20%, NO significantly increased (p<0.05) and TNF-α was up to 4 folds compared to uninfected cells after 25 hrs of infection. Meanwhile, the expression level of NF-κB was inclined from 2.5 to 6 folds during 1 to 9 hours of infection. Two-folds of expression level of r-H2AX were also observed at the 25th hr of infection. Cell cycle analysis has shown that G1/S arrest was observed after 17 hr of infection using flow cytometry and BrdU assay. In conclusion, the infection of macrophage by A. baumannii may activate the expression of NF-κB and then release large amount of TNF-α and NO to induce inflammation reaction. Furthermore, G1/S block was observed during the infection period, which might be involved in DNA damage due to the higher expression of r-H2AX after the blocking period. Molecular investigation of cell damage will be studied in the future. This study which highlights the cytotoxicity of A. baumannii may help us to understand the interaction between the host defense system and the bacteria that leads to the progress of the diseases.