The Acinetobacter baumannii gene(s) required for bacteriophage phi-AB6 infection

• Main Authors: Jhih-Tian Yang, 楊智添
• Other Authors: Nien-Tsung Lin
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/29496420725131536255

碩士 === 慈濟大學 === 微生物學免疫學暨生物化學碩士班 === 100 === Acinetobacter baumannii is a gram-negative, nonfermentative, nonmotile coccobacillus. Multidrug-resistant strains of A. baumannii (MDR-AB) are increasingly being reported worldwide, especially in intensive care units (ICUs), as the cause of outbreaks of nosocomial infections. phi-AB6 is a lytic bacteriophage specifically infecting A. baumannii. The purpose of this study was to understand the interaction between phi-AB6 and its host. To identify the phi-AB6-specific receptor, A. baumannii strain 54149 was mutated by Tn10 insertion and Kmr transconjugants were obtained. Spot test was performed to test the susceptibility of these transconjugants to phi-AB6. Twelve resistant strains were obtained. To analyze the transposon insertion site, inverse PCR was performed and the amplicon was sequenced. Sequence analysis of 8 of 12 resistant strains revealed that Tn10 insertion genes were A1S_2630, A1S_1109, A1S_0250, A1S_3152, A1S_0492 and A1S_3207, corresponding to ATCC 17978 respectively, and ABauAB_10017 and ABauAB_10542 corresponding to AB900 respectively. One of these mutants, disrupted the D-3-phosphoglycerate dehydrogenase (3PGDH) gene, was designated as J731 and picked up for further study. Adsorption assay showed that phi-AB6 adsorbed inefficiently in J731, while propagation assay showed that there were no difference between J731 and its parent strain with phage progeny release. These results suggest that 3PGDH gene is required for the adsorption of phi-AB6. In addition, we observed that glucose and N-acetyl-glucosamine would accelerate the phi-AB6 adsorption during infection period.