title: Matrix-assisted laser desorption and ionization-time-of-flight mass spectrometry, 16S rRNA gene sequencing, and API 32E for identification of Cronobacter spp.: a comparative study.
abstract: Twenty-two isolates of the family Enterobacteriaceae, with focus on Cronobacter isolated from infant formula and the environment of milk powder plants, were comparatively identified using API 32E (bioMérieux, Marcy l'Etoile, France), 16S rRNA gene sequencing (Accugenix,  Newark, USA), and matrix-assisted laser desorption and ionization-time-of-flight mass spectrometry (MALDI-TOF MS; Mabritec, Riehen, Switzerland and AnagnosTec, Potsdam, Germany). With API 32E, 22% of the isolates were assigned to species, 64% were assigned to a genus, and 14% could not  be discriminated at any taxonomic level. Both 16S rRNA gene sequencing and MALDI-TOF MS assigned 100% of the isolates to species, but the identifications based on MALDI-TOF MS results were more discriminating and unequivocal. Our data indicate that MALDI-TOF MS provides the most rapid and  unambiguous identification of Cronobacter and closely related Enterobacteriaceae isolates.
authors.affiliation: Central Laboratories Friedrichsdorf, Bahnstr. 14-30, 61381 Friedrichsdorf, Germany.
authors.forename: Sha
authors.initials: S
authors.lastname: Zhu
authors.forename: Stefan
authors.initials: S
authors.lastname: Ratering
authors.forename: Sylvia
authors.initials: S
authors.lastname: Schnell
authors.forename: Ron
authors.initials: R
authors.lastname: Wacker
mesh_terms: D059126:Cronobacter / Q000145:classification* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000382:microbiology; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S