A simple, rapid typing method for Streptococcus agalactiae based on ribosomal subunit proteins by MALDI-TOF MS

• Published in: Scientific reports 2020-05, Vol.10 (1), p.8788, Article 8788
• Main Authors: Rothen, Julian, Sapugahawatte, Dulmini Nanayakkara, Li, Carmen, Lo, Norman, Vogel, Guido, Foucault, Frédéric, Pflüger, Valentin, Pothier, Joёl F., Blom, Jochen, Daubenberger, Claudia, Ip, Margaret
• Format: Article
• Language: English
• Subjects: 631/326; 692/308; Animal diseases; Animals; Bacterial Typing Techniques - methods; Fishes - microbiology; Food; Food sources; Genotypes; High-throughput screening; Humanities and Social Sciences; Humans; Meningitis; Microbiology; Molecular Weight; multidisciplinary; Neonates; Phylogeny; Ribosome Subunits - metabolism; Science; Science (multidisciplinary); Serotypes; Serotyping; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Strains (organisms); Streptococcal Infections - microbiology; Streptococcal Infections - veterinary; Streptococcus agalactiae; Streptococcus agalactiae - classification; Streptococcus agalactiae - isolation & purification; Streptococcus agalactiae - metabolism; Streptococcus infections; Swine - microbiology; Zoonoses; Zoonoses - microbiology
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-65707-5

Streptococcus agalactiae (Group B Streptococcus , GBS), is a frequent human colonizer and a leading cause of neonatal meningitis as well as an emerging pathogen in non-pregnant adults. GBS possesses a broad animal host spectrum, and recent studies proved atypical GBS genotypes can cause human invasive diseases through animal sources as food-borne zoonotic infections. We applied a MALDI-TOF MS typing method, based on molecular weight variations of predefined 28 ribosomal subunit proteins (rsp) to classify GBS strains of varying serotypes into major phylogenetic lineages. A total of 249 GBS isolates of representative and varying capsular serotypes from patients and animal food sources (fish and pig) collected during 2016–2018 in Hong Kong were analysed. Over 84% (143/171) noninvasive carriage GBS strains from patients were readily typed into 5 globally dominant rsp-profiles. Among GBS strains from food animals, over 90% (57/63) of fish and 13% (2/15) of pig GBS matched with existing rsp-profiles, while the remainder were classified into two novel rsp-profiles and we failed to assign a fish strain into any cluster. MALDI-TOF MS allowed for high-throughput screening and simultaneous detection of novel, so far not well described GBS genotypes. The method shown here is rapid, simple, readily transferable and adapted for use in a diagnostic microbiology laboratory with potential for the surveillance of emerging GBS genotypes with zoonotic potential.