Characterization of the Acinetobacter baumannii growth phase-dependent and serum responsive transcriptomes

Anna C. Jacobs, Khalid Sayood, Stephen B. Olmsted, Catlyn E. Blanchard, Steven Heye Hinrichs, David Russell, Paul M. Dunman

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Acinetobacter baumannii has emerged as a bacterial pathogen of considerable healthcare concern. Yet, little is known about the organism's basic biological processes and the regulatory networks that modulate expression of its virulence factors and antibiotic resistance. Using Affymetrix GeneChips ®, we comprehensively defined and compared the transcriptomes of two A. baumannii strains, ATCC 17978 and 98-37-09, during exponential and stationary phase growth in Luria-Bertani (LB) medium. Results revealed that in addition to expected growth phase-associated metabolic changes, several putative virulence factors were dramatically regulated in a growth phase-dependent manner. Because a common feature between the two most severe types of A. baumannii infection, pneumonia and septicemia, includes the organism's dissemination to visceral organs via the circulatory system, microarray studies were expanded to define the expression properties of A. baumannii during growth in human serum. Growth in serum significantly upregulated iron acquisition systems, genes associated with epithelial cell adherence and DNA uptake, as well as numerous putative drug efflux pumps. Antibiotic susceptibility testing verified that the organism exhibits increased antibiotic tolerance when cultured in human serum, as compared to LB medium. Collectively, these studies provide researchers with a comprehensive database of A. baumannii's expression properties in LB medium and serum and identify biological processes that may contribute to the organism's virulence and antibiotic resistance.

Original languageEnglish (US)
Pages (from-to)403-412
Number of pages10
JournalFEMS Immunology and Medical Microbiology
Volume64
Issue number3
DOIs
Publication statusPublished - Apr 1 2012

    Fingerprint

Keywords

  • Acinetobacter baumannii
  • Microarrays
  • Serum

ASJC Scopus subject areas

  • Immunology and Allergy
  • Microbiology
  • Immunology
  • Microbiology (medical)
  • Infectious Diseases

Cite this