||ppGpp signaling plays a critical role in biofilm formation and virulence of Acinetobacter baumannii
||63. Kyeongmin Kim, Md. Maidul Islam, Hye-won Jung, Daejin Lim, Kwangsoo Kim, Sung-gwon Lee, Chungoo Park, Je Chul Lee and Minsang Shin
||Virulence (2021) 12(1): 2122-2132
Acinetobacter baumannii, a major nosocomial pathogen, survives in diverse hospital environments, and its multidrug-resistance is a major concern. The ppGpp-dependent stringent response mediates the reprogramming of genes with multifarious functions in several bacteria. We investigated whether ppGpp is involved in A. baumannii pathogenesis by examining biofilm formation, surface motility, adhesion, and invasion and by mouse infection studies. A transcriptome analysis of early stationary phase cultures revealed 498 differentially expressed genes (≥2-fold change) in a (p)ppGpp- deficient A. baumannii strain; 220 and 278 genes were up- and downregulated, respectively. Csu operon expression, important in pilus biosynthesis during early biofilm formation, was reduced significantly in the ppGpp-deficient strain. Our findings suggest that ppGpp signaling plays a critical role in A. baumannii biofilm formation, surface motility, adherence, and virulence. We showed an association between ppGpp and pathogenicity in A. baumannii for the first time; ppGpp may be a novel antivirulence target in A. baumannii.