title: Antiserum against Raoultella terrigena ATCC 33257 identifies a large number of Raoultella and Klebsiella clinical isolates as serotype O12.
abstract: Raoultella terrigena ATCC 33257, recently reclassified from the genus Klebsiella, is a drinking water isolate and belongs to a large group of non-typeable Klebsiella and Raoultella strains. Using an O-antiserum against a capsule-deficient mutant of this strain, we could show a high prevalence (10.5%) of the R. terrigena O-serotype among non-typeable, clinical Klebsiella and Raoultella isolates. We observed a strong serological cross-reaction with the K. pneumoniae O12 reference strain, indicating that a large percentage of these non-typeable strains may belong to the O12 serotype, although these are currently not detectable by the K. pneumoniae O12 reference antiserum in use. Therefore, we analyzed the O-polysaccharide (O-PS) structure and genetic organization of the wb gene cluster of R. terrigena ATCC 33257, and both confirmed a close relation of R. terrigena and K. pneumoniae O12. The two strains possess an identical O-PS, lipopolysaccharide core structure, and genetic organization of the wb gene cluster. Heterologous expression of the R. terrigena wb gene cluster in Escherichia coli K-12 resulted in the WecA-dependent synthesis of an O-PS reactive with the K. pneumoniae O12 antiserum. The serological data presented here suggest a higher prevalence of the O12-serotype among Klebsiella and Raoultella isolates than generally assumed.
authors.affiliation: Division of Medical and Biochemical Microbiology, Leibniz-Center for Medicine and Biosciences, Research Center Borstel, Borstel, Germany. kmertens@medicine.tamhsc.edu
authors.forename: Katja
authors.initials: K
authors.lastname: Mertens
authors.forename: Sven
authors.initials: S
authors.lastname: Müller-Loennies
authors.forename: Petra
authors.initials: P
authors.lastname: Stengel
authors.forename: Rainer
authors.initials: R
authors.lastname: Podschun
authors.forename: Dennis S
authors.initials: DS
authors.lastname: Hansen
authors.forename: Uwe
authors.initials: U
authors.lastname: Mamat
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D003001:Cloning, Molecular; D003429:Cross Reactions / Q000276:immunology; D004269:DNA, Bacterial / Q000302:isolation & purification; D055786:Gene Knockout Techniques; D007711:Klebsiella pneumoniae / Q000145:classification* / Q000276:immunology*; D019081:O Antigens / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D012703:Serotyping; D013045:Species Specificity; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D019081:O Antigens