en
Scientific article
Open access
English

Mechanical ventilation alters the development of Staphylococcus aureus pneumonia in rabbit

Published inPLOS ONE, vol. 11, no. 7, e0158799
Publication date2016
Abstract

Ventilator-associated pneumonia (VAP) is common during mechanical ventilation (MV). Beside obvious deleterious effects on muco-ciliary clearance, MV could adversely shift the host immune response towards a pro-inflammatory pattern through toll-like receptor (TLRs) up-regulation. We tested this hypothesis in a rabbit model of Staphylococcus aureus VAP. Pneumonia was caused by airway challenge with S. aureus, in either spontaneously breathing (SB) or MV rabbits (n = 13 and 17, respectively). Pneumonia assessment regarding pulmonary and systemic bacterial burden, as well as inflammatory response was done 8 and 24 hours after S. aureus challenge. In addition, ex vivo stimulations of whole blood taken from SB or MV rabbits (n = 7 and 5, respectively) with TLR2 agonist or heat-killed S. aureus were performed. Data were expressed as mean±standard deviation. After 8 hours of infection, lung injury was more severe in MV animals (1.40±0.33 versus [vs] 2.40±0.55, p = 0.007), along with greater bacterial concentrations (6.13±0.63 vs. 4.96±1.31 colony forming units/gram, p = 0.002). Interleukin (IL)-8 and tumor necrosis factor (TNF)-αserum concentrations reached higher levels in MV animals (p = 0.010). Whole blood obtained from MV animals released larger amounts of cytokines if stimulated with TLR2 agonist or heat-killed S. aureus (e.g., TNF-α: 1656±166 vs. 1005±89; p = 0.014). Moreover, MV induced TLR2 overexpression in both lung and spleen tissue. MV hastened tissue injury, impaired lung bacterial clearance, and promoted a systemic inflammatory response, maybe through TLR2 overexpression.

Keywords
  • Animals
  • Interleukin-8/immunology
  • Pneumonia
  • Staphylococcal/immunology/pathology
  • Pneumonia
  • Ventilator-Associated/immunology/microbiology/pathology
  • Rabbits
  • Respiration
  • Artificial
  • Staphylococcus aureus/immunology
  • Toll-Like Receptor 2/immunology
  • Tumor Necrosis Factor-alpha/immunology
Citation (ISO format)
BARBAR, Saber-Davide et al. Mechanical ventilation alters the development of Staphylococcus aureus pneumonia in rabbit. In: PLOS ONE, 2016, vol. 11, n° 7, p. e0158799. doi: 10.1371/journal.pone.0158799
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Article (Published version)
Identifiers
ISSN of the journal1932-6203
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