Procedures for determining the susceptibility of contracting a nosocomial infection in a patient and a prognosis of evolution of a septic syndrome

Procedure for determining the susceptibility of a patient contracting a nosocomial infection in which: a) provides a biological sample of a patient and the biological material of the biological sample b) is extracted features at least one specific reagent of expression product of at least one target gene is the gene S100A9 c) expression of S100A9 target gene is determined, overexpression being relative to a given limit value, an indication of susceptibility of contracting a nosocomial infection.