A Chamber Study on Evaluation of Airborn Acinetobacter Baumannii by Propidium Monoazide Quantitative PCR.

• Main Authors: Chieh-Chen Cheng, 鄭杰真
• Other Authors: Chun-Chieh Tseng
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/64944770786936399707

碩士 === 慈濟大學 === 公共衛生學系碩士班 === 101 === Acinetobacter baumannii (A. baumannii) is an important pathogen that can cause nosocomial infections. Although major infection routes of A. baumannii is contagious, airborne or droplet transmission lead to pneumonia by A. baumannii infection is still possible to cause nosocomial infections. Therefore, how to detect and quantify viable Acinetobacter baumannii in air has become an important issue. The culture-based method still remains the dominant method for quantifying bioaerosol concentrations; however, this method may not be the most time-efficient method for extensively monitoring A. baumannii or for testing their antibiotic resistance. In the recent years, qPCR is considered to be more rapid, sensitive, and specific to quantify bioaerosols. However, there are some limitations for qPCR; high copy numbers of DNA were detected do not necessarily mean that any of this microbe is viable. In order to overcome this disadvantage, there are some investigations have devoted to determine the integrity of cell membrane as an indicator of bacterial viability by PMA-qPCR. Therefore, the application of PMA-qPCR to environmental samples should provide crucial information on both the identity and viability of A. baumannii. Therefore, the purpose of this study is to establish the optimal PMA-qPCR method for A. baumannii identification. In this study, the optimal PMA-qPCR method to detect A. baumannii is by using 10 μg/ml of PMA combined with 500W halogen light for 3 minutes irridation. From the viability test, both PMA-qPCR and culture can distinguish whether the A. baumannii is viable or not. Among the collection efficiency of different bioaerosol samplers, BioSampler with no supplement during the sampling demonstrated greatest efficiencies. In addition, our results showed the sampling performance of BioSampler and AGI-30 were better than those of Nuclepore filter. Regarding the storage test, the stability of PMA-binding DNA can be maintained for at least 28 days at 4°C. However, the effect of refreezing on A. baumannii survival demonstrated that A. baumannii was unstable when the sample was frozen repeatedly. Finally, our results indicated that 2μg/ml of colistin for 5 minutes treatment with airborne A. baumannii can be the most effective way to detect viable colistin-resistant A. baumannii in the air.