title: Singleton Sequence Type 382, an Emerging Clonal Group of Listeria monocytogenes Associated with Three Multistate Outbreaks Linked to Contaminated Stone Fruit, Caramel Apples, and Leafy Green Salad.
abstract: Three multistate outbreaks between 2014 and 2016, involving case patients in and outside the United States, were linked to stone fruit, caramel apples, and packaged leafy green salad contaminated withListeria monocytogenessingleton sequence type 382 (ST382), a serotype IVb-v1 clone with limited genomic divergence. Isolates from these outbreaks and other ST382 isolates not associated with these outbreaks were analyzed by whole-genome sequencing (WGS) analysis. The primary differences among ST382 strains were single nucleotide polymorphisms (SNPs). WGS analysis differentiated ST382 from a clonal complex 1 outbreak strain co-contaminating the caramel apples. WGS clustered food, environmental, and clinical isolates within each outbreak, and also differentiated among the three outbreak strains and epidemiologically unrelated ST382 isolates, which were indistinguishable by pulsed-field gel electrophoresis. ST382 appeared to be an emerging clone that began to diverge from its ancestor approximately 32 years before 2016. We estimated that there was 1.29 nucleotide substitution per genome (2.94 Mbp) per year for this clone.
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA yi.chen@fda.hhs.gov.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: James
authors.initials: J
authors.lastname: Pettengill
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Ruth
authors.initials: R
authors.lastname: Timme
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: David
authors.initials: D
authors.lastname: Melka
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Doyle
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Alikeh
authors.initials: A
authors.lastname: Jackson
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Mickey
authors.initials: M
authors.lastname: Parish
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hammack
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Marc W
authors.initials: MW
authors.lastname: Allard
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Brown
authors.affiliation: Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland, USA.
authors.forename: Errol A
authors.initials: EA
authors.lastname: Strain
mesh_terms: D000293:Adolescent; D000368:Aged; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks; D005260:Female; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology; D016680:Genome, Bacterial; D005838:Genotype; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008088:Listeriosis / Q000453:epidemiology* / Q000382:microbiology; D008297:Male; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D020641:Polymorphism, Single Nucleotide; D014481:United States
chemical_list: D004269:DNA, Bacterial
keywords: clone; outbreak; singleton ST382; whole-genome sequencing