Gene expression profiling in human neutrophils after infection with Acinetobacter baumannii in vitro.

María Lázaro-Díez,J Gonzalo Ocejo-Vinyals,Marcos López-Hoyos,José Ramos-Vivas,Borja Suberbiola,Itziar Chapartegui-González,Rita G Sobral

doi:10.1371/journal.pone.0242674

Abstract

Acinetobacter baumannii is a Gram negative nosocomial pathogen that has acquired increasing worldwide notoriety due to its high antibiotic resistance range and mortality rates in hospitalized patients. Therefore, it is necessary to better understand key aspects of A. baumannii pathogenesis such as host-pathogen interactions. In this report, we analyzed both gene expression and cytokine production by human neutrophils infected with A. baumannii. Our assays reveal a proinflammatory response of neutrophils after A. baumannii infection, since intracellular transcription of effector proteins such as COX-2, transcription factors, and proinflammatory cytokines resulted significantly upregulated in neutrophils infected by A. baumannii, compared with unstimulated human neutrophils. Translation and release of CXCL-8, IL-1β and TNF-α by neutrophils was confirmed by protein quantification in culture supernatants. Results obtained in this report reinforce the importance of human neutrophils in controlling A. baumannii infections but also emphasize the proinflammatory nature of these host-pathogen interactions as a target for future immunomodulatory therapies.

Highlights

Acinetobacter baumannii is a Gram negative nosocomial bacterial species that has emerged as an important pathogen causing infections such as pneumonia and bacteremia
One of the strategies is to modulate the disproportionate response that occurs when immune cells interact with some pathogenic bacteria and produce a series of cytokines that lead to an exacerbated inflammatory response that may be more difficult to control than the infection itself
Acinetobacter does not have special factors to be virulent, it does not have important toxins, or mobility, and lacks strong adherence to human epithelial cells in vitro [3, 13], but it is quickly phagocytized by neutrophils [4]

Summary

Introduction

Acinetobacter baumannii is a Gram negative nosocomial bacterial species that has emerged as an important pathogen causing infections such as pneumonia and bacteremia. The main problem in combating this bacteria is the high antibiotic resistance range, with some strains even presenting resistance to all the types of antimicrobials available in the clinical practice (pandrug resistant strains) [1, 2]. Considering the importance of this pathogen, the study of its interaction with host cells becomes crucial [2]. The interaction of this bacterium with epithelial cells indicates that it has limited virulence [3].

Methods

Results

Conclusion