title: Molecular characterization of the 2011 Hong Kong scarlet fever outbreak.
abstract: A scarlet fever outbreak occurred in Hong Kong in 2011. The majority of cases resulted in the isolation of Streptococcus pyogenes emm12 with multiple antibiotic resistances. Phylogenetic analysis of 22 emm12 scarlet fever outbreak isolates, 7 temporally and geographically matched emm12 non-scarlet fever isolates, and 18 emm12 strains isolated during 2005-2010 indicated the outbreak was multiclonal. Genome sequencing of 2 nonclonal scarlet fever isolates (HKU16 and HKU30), coupled with diagnostic polymerase chain reaction assays, identified 2 mobile genetic elements distributed across the major lineages: a 64.9-kb integrative and conjugative element encoding tetracycline and macrolide resistance and a 46.4-kb prophage encoding superantigens SSA and SpeC and the DNase Spd1. Phenotypic comparison of HKU16 and HKU30 with the S. pyogenes M1T1 strain 5448 revealed that HKU16 displays increased adherence to HEp-2 human epithelial cells, whereas HKU16, HKU30, and 5448 exhibit equivalent resistance to neutrophils and virulence in a humanized plasminogen murine model. However, in contrast to M1T1, the virulence of HKU16 and HKU30 was not associated with covRS mutation. The multiclonal nature of the emm12 scarlet fever isolates suggests that factors such as mobile genetic elements, environmental factors, and host immune status may have contributed to the 2011 scarlet fever outbreak.
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, China. htse@hkucc.hku.hk
authors.forename: Herman
authors.initials: H
authors.lastname: Tse
authors.forename: Jessie Y J
authors.initials: JY
authors.lastname: Bao
authors.forename: Mark R
authors.initials: MR
authors.lastname: Davies
authors.forename: Peter
authors.initials: P
authors.lastname: Maamary
authors.forename: Hoi-Wah
authors.initials: HW
authors.lastname: Tsoi
authors.forename: Amy H Y
authors.initials: AH
authors.lastname: Tong
authors.forename: Tom C C
authors.initials: TC
authors.lastname: Ho
authors.forename: Chi-Ho
authors.initials: CH
authors.lastname: Lin
authors.forename: Christine M
authors.initials: CM
authors.lastname: Gillen
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Barnett
authors.forename: Jonathan H K
authors.initials: JH
authors.lastname: Chen
authors.forename: Mianne
authors.initials: M
authors.lastname: Lee
authors.forename: Wing-Cheong
authors.initials: WC
authors.lastname: Yam
authors.forename: Chi-Kin
authors.initials: CK
authors.lastname: Wong
authors.forename: Cheryl-Lynn Y
authors.initials: CL
authors.lastname: Ong
authors.forename: Yee-Wai
authors.initials: YW
authors.lastname: Chan
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Wu
authors.forename: Tony
authors.initials: T
authors.lastname: Ng
authors.forename: Wilina W L
authors.initials: WW
authors.lastname: Lim
authors.forename: Thomas H F
authors.initials: TH
authors.lastname: Tsang
authors.forename: Cindy W S
authors.initials: CW
authors.lastname: Tse
authors.forename: Gordon
authors.initials: G
authors.lastname: Dougan
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Walker
authors.forename: Si
authors.initials: S
authors.lastname: Lok
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
mesh_terms: D000293:Adolescent; D000328:Adult; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D016680:Genome, Bacterial; D023281:Genomics; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007223:Infant; D020071:Interspersed Repetitive Sequences; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010641:Phenotype; D010802:Phylogeny; D012541:Scarlet Fever / Q000453:epidemiology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000187:drug effects / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins