The host control of a clinical isolate strain of P. aeruginosa infection is independent of Nod-1 but depends on MyD88.

OBJECTIVE AND DESIGN: The objective of this study was to investigate the role of Nod1 in the recruitment of neutrophils into the infection site and in the establishment of the inflammatory response elicited by a clinical isolate strain of P. aeruginosa in vivo, while comparing it to the well-established role of MyD88 in this process.

SUBJECTS: Wild-type, Nod1-/- and MyD88-/- mice, all with a C57Bl/6 background.

METHODS: Mice were intranasally infected with Pseudomonas aeruginosa DZ605. Bronchoalveolar lavage and blood were harvested 6 or 20 h post-infection for evaluating bacterial load, chemokine levels and neutrophil migration. Survival post-infection was also observed.

RESULTS: We show here that wild-type and Nod1-/- mice induce similar lung chemokine levels, neutrophil recruitment, and bacterial load, thus leading to equal survival rates upon P. aeruginosa pulmonary infection. Furthermore, we confirmed the essential role of MyD88-dependent signalling in recruiting neutrophils and controlling P. aeruginosa-induced pulmonary infection.

CONCLUSION: The results suggest that in contrast to MyD88, under our experimental conditions, the absence of Nod1 does not impair the recruitment of neutrophils in response to P. aeruginosa DZ605.