title: Genotyping and Source Tracking of Cronobacter sakazakii and C. malonaticus Isolates from Powdered Infant Formula and an Infant Formula Production Factory in China.
abstract: Cronobacter spp. (formerly defined as Enterobacter sakazakii) are opportunistic bacterial pathogens of both infants and adults. In this study, we analyzed 70 Cronobacter isolates from powdered infant formula (PIF) and an infant formula production facility in China to determine possible contamination routes. The strains were profiled by multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), PCR-based O-antigen serotyping, and ompA and rpoB sequence analyses. The isolates were primarily Cronobacter sakazakii (66/70) or Cronobacter malonaticus (4/70). The strains were divided into 38 pulsotypes (PTs) using PFGE and 19 sequence types (STs) by MLST. In contrast, rpoB and ompA sequence analyses divided the strains into 10 overlapping clusters each. PCR serotyping of the 66 C. sakazakii and 4 C. malonaticus strains resulted in the identification of four C. sakazakii serotypes (O1, O2, O4, and O7) and a single C. malonaticus serotype, O2. The dominant C. sakazakii sequence types from PIF and an infant formula production factory in China were C. sakazakii clonal complex 4 (CC4) (n = 19), ST1 (n = 14), and ST64 (n = 11). C. sakazakii CC4 is a clonal lineage strongly associated with neonatal meningitis. In the process of manufacturing PIF, the spray-drying, fluidized-bed-drying, and packing areas were the main areas with Cronobacter contamination. C. sakazakii strains with the same pulsotypes (PT3 and PT2) and sequence types (ST1 and ST64) were isolated both from processing equipment and from the PIF finished product.
authors.affiliation: Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Fei
authors.affiliation: National Research Center of Dairy Engineering and Technology, Northeast Agricultural University, Harbin, China.
authors.forename: Chaoxin
authors.initials: C
authors.lastname: Man
authors.affiliation: Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China.
authors.forename: Binbin
authors.initials: B
authors.lastname: Lou
authors.affiliation: Pathogen Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Forsythe
authors.affiliation: Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China.
authors.forename: Yunlei
authors.initials: Y
authors.lastname: Chai
authors.affiliation: Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Li
authors.affiliation: Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China.
authors.forename: Jieting
authors.initials: J
authors.lastname: Niu
authors.affiliation: Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China National Research Center of Dairy Engineering and Technology, Northeast Agricultural University, Harbin, China Synergetic Innovation Center of Food Safety and Nutrition, Northeast Agricultural University, Harbin, China yujun_jiang@163.com.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D002681:China; D016000:Cluster Analysis; D059126:Cronobacter / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004783:Environmental Microbiology; D005511:Food Handling; D005838:Genotype; D060005:Genotyping Techniques; D006801:Humans; D041943:Infant Formula / Q000382:microbiology*; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D019081:O Antigens / Q000235:genetics; D016133:Polymerase Chain Reaction; D017385:Sequence Homology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D019081:O Antigens; C078167:OMPA outer membrane proteins; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit