title: A proposed harmonized LPS molecular-subtyping scheme for Cronobacter species.
abstract: Cronobacter are opportunistic pathogens, which cause infections in all age groups. To aid the characterization of Cronobacter in foods and environments a harmonized LPS identification scheme for molecular serotyping is needed. To this end, we studied 409 Cronobacter isolates representing the seven Cronobacter species using two previously reported molecular serotyping schemes, described here as Mullane-Jarvis (M-J) and Sun schemes. PCR analysis revealed many overlapping results that were obtained when independently applying the two serotyping schemes. There were complete agreements between the two PCR schemes for Cronobacter sakazakii (Csak) O:1, Csak O:3, and Csak O:7 serotypes. However, only thirty-five of 41 Csak O:4 strains, identified using the M-J scheme, were PCR-positive with the Sun scheme primers. Also the Sun scheme Csak O:5 primers failed to identify this serotype in any of the C. sakazakii strains tested, but did recognize seven Cronobacter turicensis strains, which were identified as Ctur O:3 using the M-J scheme. Similarly, the Sun scheme Csak O:6 primers recognized 30 Cronobacter malonaticus O:2 strains identified with the M-J scheme, but failed to identify this serotype in any C. sakazakii strain investigated. In this report, these findings are summarized and a harmonized molecular-serotyping scheme is proposed which is predicated on the correct identification of Cronobacter species, prior to serotype determination. In summary, fourteen serotypes were identified using the combined protocol, which consists of Csak O:1-O:4, and Csak O:7; Cmal O:1-O:2; Cdub O:1-O:2, Cmuy O:1-O:2, Cuni O:1, as well as Ctur O:1 and Ctur O:3.
authors.affiliation: UCD Centre for Food Safety, WHO Collaborating Centre for Research, Reference, and Training on Cronobacter, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Qiongqiong
authors.initials: Q
authors.lastname: Yan
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Karen G
authors.initials: KG
authors.lastname: Jarvis
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Hannah R
authors.initials: HR
authors.lastname: Chase
authors.affiliation: Food Directorate, Bureau of Microbial Hazards/Health Canada, Ottawa, ON, Canada.
authors.forename: Karine
authors.initials: K
authors.lastname: Hébert
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Larisa H
authors.initials: LH
authors.lastname: Trach
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Chloe
authors.initials: C
authors.lastname: Lee
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Sadowski
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Boram
authors.initials: B
authors.lastname: Lee
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Seongeun
authors.initials: S
authors.lastname: Hwang
authors.affiliation: CFSAN, FDA, Laurel, MD, USA.
authors.forename: Venugopal
authors.initials: V
authors.lastname: Sathyamoorthy
authors.affiliation: Mead Johnson Nutrition, Evansville, IN, USA.
authors.forename: Niall
authors.initials: N
authors.lastname: Mullane
authors.affiliation: CFSAN, FDA, College Park, MD, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Pava-Ripoll
authors.affiliation: College of Life Sciences, University of Dundee, Scotland, UK.
authors.forename: Carol
authors.initials: C
authors.lastname: Iversen
authors.affiliation: Food Directorate, Bureau of Microbial Hazards/Health Canada, Ottawa, ON, Canada.
authors.forename: Franco
authors.initials: F
authors.lastname: Pagotto
authors.affiliation: UCD Centre for Food Safety, WHO Collaborating Centre for Research, Reference, and Training on Cronobacter, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Séamus
authors.initials: S
authors.lastname: Fanning
authors.affiliation: CFSAN, FDA, Laurel, MD, USA. Electronic address: ben.tall@fda.hhs.gov.
authors.forename: Ben D
authors.initials: BD
authors.lastname: Tall
mesh_terms: D059126:Cronobacter / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D044083:Cronobacter sakazakii / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D005516:Food Microbiology; D008070:Lipopolysaccharides / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D058889:Molecular Typing / Q000379:methods*; D016133:Polymerase Chain Reaction; D012703:Serotyping / Q000379:methods*; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D008070:Lipopolysaccharides
keywords: Cronobacter; LPS; Molecular serotyping; SDS-PAGE