To address this gap, we discovered that coadministration of human recombinant human cystatins 9 (rCST9) and C (rCSTC) is an effective immunomodulatory therapy that provides unprecedented survival outcomes against pneumonia induced by an intranasal (i.n.)challenge with MDR NDM-1 K. pneumoniae (1). This evidence concerns the gene CST9 and susceptibility to pneumonia measurement.