FIG 4.
CPK identification. (A) Prevalidation. Kappa values for CPK identification (KPC versus OXA-48) obtained in three hospitals for four data processing bioinformatic tool combinations (PLSDA-MTHRESHOLD, PLSDA-MLINEAR, RF-MTHRESHOLD, and RF-MLINEAR) for both raw and normalized spectra. PLSDA, partial least square discriminant analysis; RF, random forest; THRESHOLD, threshold mode of spectrum acquisition; LINEAR, linear mode of spectrum acquisition; Norm, normalized; HGUGM, Hospital General Universitario Gregorio Marañon; CHUAC, Complexo Hospitalario Universitario A Coruña; HUPM, Hospital Universitario Puerta del Mar. (B) Training. Kappa values obtained in the training set versus the number of isolates used for both raw and normalized spectra. (C) Final validation. 1. Identification of CPK isolates. Kappa values obtained with a group of 122 isolates (84 CPK and 38 non-CPK) processed at the CHUAC by MALDI-TOF MS and four bioinformatic tool combinations. 2. Identification of the type of carbapenemase. Kappa values obtained for the 84 CPK isolates when identification of the type of carbapenemase (OXA-48, KPC, and NDM) was performed.