Background: Clostridium difficile infection (CDI) associated with emerging ribotypes is increased both in Europe and worldwide; more than 800 different ribotypes and 34 different toxinotypes of C. difficile are known and the ribotype 027 strain is currently considered the most virulent. In Europe, nosocomial CDI are typically associated with ribotype 027 and 078 strains, while in Italy, the predominant ribotypes are associated to 356/607 (27%) and 018 (12%) strains. Unlike other European countries, the hypervirulent ribotypes 027 and 078 emerged in Italy only recently and accounted for 8% and 4% respectively. In this study MALDI-TOF mass spectRometry was used as a potential innovative method for C. difficile strains typing, compared with the widely known PCR-Ribotyping method. Materials/methods: Fifty strains of C. difficile isolated in our hospital were typed both by PCR-Ribotyping, according to Bidet et al., and by MALDI-TOF MS. The spectra obtained in the range 2-20 kDa, with the instrument Autoflex speed (Bruker Daltonics, Germany), were analyzed and subsequently imported into the ClinProTools software version 2.2 (Bruker Daltonics) to carry out a statistical analysis in order to verify the presence of specific peaks for each ribotype. Results: The two typing methods used showed a concordance of 76%. Using PCR-Ribotyping, 5 different ribotypes (named PR1-PR5) were observed, 2 of these, PR1 and PR3, associated to ribotypes 018 and 0126, respectively. MALDI-TOF MS, based on the presence/absence of 13 different peaks, differentiates the 5 ribotypes identified by PCR-Ribotyping. For eight strains (16%)the spectra obtained were classified by the MALDI-TOF MS statistical software as one of such 5 ribotypes but differently to the classification of PCR-Ribotyping. For 4 strains (8%) a protein profile different from each other and from those characterizing the 5 ribotypes observed was obtained, making them unique and belonging to different classes (PR6-PR9). Conclusions: MALDI-TOF MS typing compared to other molecular typing methods was faster and cheaper. However, the typing of strains, although possible as demonstrated in this study and presenting significant advantages, is currently applicable to the most frequently circulating ribotypes, as a first-level epidemiological investigation in the nosocomial setting
Typing of Clostridioides difficile isolates by MALDI-TOF MS / Calderaro, A.; Buttrini, M.; Montecchini, S.; Covan, S.; Ruggeri, A.; Martinelli, M.; Larini, S.; Arcangeletti, M. C.; Chezzi, C.; De Conto, F. - (2020). (Intervento presentato al convegno XXX European Congress of Clinical Microbiology and Infectious Diseases (ECCMID)).
Typing of Clostridioides difficile isolates by MALDI-TOF MS
Calderaro A.;Buttrini M.;Montecchini S.;Covan S.;Martinelli M.;Arcangeletti M. C.;Chezzi C.;De Conto F
2020-01-01
Abstract
Background: Clostridium difficile infection (CDI) associated with emerging ribotypes is increased both in Europe and worldwide; more than 800 different ribotypes and 34 different toxinotypes of C. difficile are known and the ribotype 027 strain is currently considered the most virulent. In Europe, nosocomial CDI are typically associated with ribotype 027 and 078 strains, while in Italy, the predominant ribotypes are associated to 356/607 (27%) and 018 (12%) strains. Unlike other European countries, the hypervirulent ribotypes 027 and 078 emerged in Italy only recently and accounted for 8% and 4% respectively. In this study MALDI-TOF mass spectRometry was used as a potential innovative method for C. difficile strains typing, compared with the widely known PCR-Ribotyping method. Materials/methods: Fifty strains of C. difficile isolated in our hospital were typed both by PCR-Ribotyping, according to Bidet et al., and by MALDI-TOF MS. The spectra obtained in the range 2-20 kDa, with the instrument Autoflex speed (Bruker Daltonics, Germany), were analyzed and subsequently imported into the ClinProTools software version 2.2 (Bruker Daltonics) to carry out a statistical analysis in order to verify the presence of specific peaks for each ribotype. Results: The two typing methods used showed a concordance of 76%. Using PCR-Ribotyping, 5 different ribotypes (named PR1-PR5) were observed, 2 of these, PR1 and PR3, associated to ribotypes 018 and 0126, respectively. MALDI-TOF MS, based on the presence/absence of 13 different peaks, differentiates the 5 ribotypes identified by PCR-Ribotyping. For eight strains (16%)the spectra obtained were classified by the MALDI-TOF MS statistical software as one of such 5 ribotypes but differently to the classification of PCR-Ribotyping. For 4 strains (8%) a protein profile different from each other and from those characterizing the 5 ribotypes observed was obtained, making them unique and belonging to different classes (PR6-PR9). Conclusions: MALDI-TOF MS typing compared to other molecular typing methods was faster and cheaper. However, the typing of strains, although possible as demonstrated in this study and presenting significant advantages, is currently applicable to the most frequently circulating ribotypes, as a first-level epidemiological investigation in the nosocomial settingI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
