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Assessment of MALDI-TOF MS as Alternative Tool for Streptococcus suis Identification.

Pérez-Sancho M, Vela AI, García-Seco T, Gottschalk M, Domínguez L, Fernández-Garayzábal JF - Front Public Health (2015)

Bottom Line: Considering the results of the present study, we suggest using a less restrictive threshold score of ≥2.000 for reliable species identification of S. suis.According to this cut-off value, a total of 125 S. suis isolates (96.9%) were correctly identified using the updated database.These data indicate an excellent performance of MALDI-TOF MS for the identification of S. suis.

View Article: PubMed Central - PubMed

Affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense , Madrid , Spain ; Campus de Excelencia Internacional (CEI) Moncloa, Universidad Politécnica de Madrid (UPM), Universidad Complutense de Madrid (UCM) , Madrid , Spain.

ABSTRACT
The accuracy of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identifying Streptococcus suis isolates obtained from pigs, wild animals, and humans was evaluated using a PCR-based identification assay as the gold standard. In addition, MALDI-TOF MS was compared with the commercial multi-tests Rapid ID 32 STREP system. From the 129 S. suis isolates included in the study and identified by the molecular method, only 31 isolates (24.03%) had score values ≥2.300 and 79 isolates (61.24%) gave score values between 2.299 and 2.000. After updating the currently available S. suis MALDI Biotyper database with the spectra of three additional clinical isolates of serotypes 2, 7, and 9, most isolates had statistically significant higher score values (mean score: 2.65) than those obtained using the original database (mean score: 2.182). Considering the results of the present study, we suggest using a less restrictive threshold score of ≥2.000 for reliable species identification of S. suis. According to this cut-off value, a total of 125 S. suis isolates (96.9%) were correctly identified using the updated database. These data indicate an excellent performance of MALDI-TOF MS for the identification of S. suis.

No MeSH data available.


Related in: MedlinePlus

MALDI-TOF MS mass spectra of S. suis (A), S. porcinus (B), and S. dysgalactiae subsp. equisimilis (C). The y axis represents the relative intensities (%) and the x axis represents the m/z values (masses in Da).
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Figure 1: MALDI-TOF MS mass spectra of S. suis (A), S. porcinus (B), and S. dysgalactiae subsp. equisimilis (C). The y axis represents the relative intensities (%) and the x axis represents the m/z values (masses in Da).

Mentions: None of the S. suis isolates included in the present study was misidentified with Streptococcus porcinus and Streptococcus dysgalactiae subsp. equisimilis, the other two most important pathogens of swine belonging to this genus, included in the ODB. The spectra of S. suis presented, regardless their serotype, distinct MS peaks (e.g., m/z 3377, 4133, and 8267) which allowed its differentiation from these two streptococcal species by MALDI-TOF MS technique (Figure 1).


Assessment of MALDI-TOF MS as Alternative Tool for Streptococcus suis Identification.

Pérez-Sancho M, Vela AI, García-Seco T, Gottschalk M, Domínguez L, Fernández-Garayzábal JF - Front Public Health (2015)

MALDI-TOF MS mass spectra of S. suis (A), S. porcinus (B), and S. dysgalactiae subsp. equisimilis (C). The y axis represents the relative intensities (%) and the x axis represents the m/z values (masses in Da).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543777&req=5

Figure 1: MALDI-TOF MS mass spectra of S. suis (A), S. porcinus (B), and S. dysgalactiae subsp. equisimilis (C). The y axis represents the relative intensities (%) and the x axis represents the m/z values (masses in Da).
Mentions: None of the S. suis isolates included in the present study was misidentified with Streptococcus porcinus and Streptococcus dysgalactiae subsp. equisimilis, the other two most important pathogens of swine belonging to this genus, included in the ODB. The spectra of S. suis presented, regardless their serotype, distinct MS peaks (e.g., m/z 3377, 4133, and 8267) which allowed its differentiation from these two streptococcal species by MALDI-TOF MS technique (Figure 1).

Bottom Line: Considering the results of the present study, we suggest using a less restrictive threshold score of ≥2.000 for reliable species identification of S. suis.According to this cut-off value, a total of 125 S. suis isolates (96.9%) were correctly identified using the updated database.These data indicate an excellent performance of MALDI-TOF MS for the identification of S. suis.

View Article: PubMed Central - PubMed

Affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense , Madrid , Spain ; Campus de Excelencia Internacional (CEI) Moncloa, Universidad Politécnica de Madrid (UPM), Universidad Complutense de Madrid (UCM) , Madrid , Spain.

ABSTRACT
The accuracy of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identifying Streptococcus suis isolates obtained from pigs, wild animals, and humans was evaluated using a PCR-based identification assay as the gold standard. In addition, MALDI-TOF MS was compared with the commercial multi-tests Rapid ID 32 STREP system. From the 129 S. suis isolates included in the study and identified by the molecular method, only 31 isolates (24.03%) had score values ≥2.300 and 79 isolates (61.24%) gave score values between 2.299 and 2.000. After updating the currently available S. suis MALDI Biotyper database with the spectra of three additional clinical isolates of serotypes 2, 7, and 9, most isolates had statistically significant higher score values (mean score: 2.65) than those obtained using the original database (mean score: 2.182). Considering the results of the present study, we suggest using a less restrictive threshold score of ≥2.000 for reliable species identification of S. suis. According to this cut-off value, a total of 125 S. suis isolates (96.9%) were correctly identified using the updated database. These data indicate an excellent performance of MALDI-TOF MS for the identification of S. suis.

No MeSH data available.


Related in: MedlinePlus