Human serum albumin alters specific genes that can play a role in survival and persistence in Acinetobacter baumannii

Sci Rep. 2018 Oct 3;8(1):14741. doi: 10.1038/s41598-018-33072-z.

Abstract

In the past few decades Acinetobacter baumannii has emerged as a notorious nosocomial pathogen because of its ability to acquire genetic material and persist in extreme environments. Recently, human serum albumin (HSA) was shown to significantly increase natural transformation frequency in A. baumannii. This observation led us to perform transcriptomic analysis of strain A118 under HSA induction to identify genes that are altered by HSA. Our results revealed the statistically significant differential expression of 296 protein-coding genes, including those associated with motility, biofilm formation, metabolism, efflux pumps, capsule synthesis, and transcriptional regulation. Phenotypic analysis of these traits showed an increase in surface-associated motility, a decrease in biofilm formation, reduced activity of a citric acid cycle associated enzyme, and increased survival associated with zinc availability. Furthermore, the expression of genes known to play a role in pathogenicity and antibiotic resistance were altered. These genes included those associated with RND-type efflux pumps, the type VI secretion system, iron acquisition/metabolism, and ß-lactam resistance. Together, these results illustrate how human products, in particular HSA, may play a significant role in both survival and persistence of A. baumannii.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acinetobacter baumannii / drug effects*
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / metabolism
  • Acinetobacter baumannii / pathogenicity
  • Bacterial Capsules / drug effects
  • Bacterial Capsules / genetics
  • Bacterial Capsules / metabolism
  • Biofilms
  • Citric Acid Cycle / drug effects
  • Citric Acid Cycle / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial / drug effects*
  • Genes, MDR / drug effects
  • Genome, Bacterial*
  • Humans
  • Ion Transport / drug effects
  • Iron / metabolism
  • Microbial Viability / drug effects
  • Serum Albumin, Human / pharmacology*
  • Transformation, Bacterial / drug effects
  • Type VI Secretion Systems / genetics
  • Type VI Secretion Systems / metabolism
  • Zinc / metabolism
  • beta-Lactam Resistance / drug effects*
  • beta-Lactam Resistance / genetics
  • beta-Lactams / pharmacology

Substances

  • Type VI Secretion Systems
  • beta-Lactams
  • Iron
  • Zinc
  • Serum Albumin, Human