title: A Hyperhemolytic/Hyperpigmented Group B Streptococcus Strain with a CovR Mutation Isolated from an Adolescent Patient with Sore Throat.
abstract: Group B Streptococci (GBS) are ß-hemolytic, gram-positive bacteria that are typically associated with infections in human newborns or immunocompromised adults. However, mutation in the two-component regulator CovR/S relieves repression of hemolysin, potentially increasing virulence of GBS. We report the isolation of hyperhemolytic/hyperpigmented GBS strain from an adolescent patient who presented to the University of Washington clinic with symptoms of sore throat. While the patient also tested positive for mononucleosis, a GBS strain with increased hemolysis was isolated from the throat swab obtained from the patient. As hyperhemolytic/hyperpigmented GBS strains are typically associated with mutations in the regulator CovR/CovS, we sequenced thecovR/Sloci in the clinical isolate. An adenine to cytosine mutation resulting in a change in amino acid coding sequence from glutamine at position 120 to proline in CovR (Q120P) was identified. Introduction of the Q120P amino acid substitution in a CovR complementation plasmid abolished complementation of a ΔcovRmutant derived from the wild type GBS serotype Ia strain A909; these results confirm that the hyperhemolysis observed in the clinical isolate is due to the Q120P substitution in CovR. Antibiotic was prescribed and the patient's symptoms resolved without reported complications. This study represents the first report of the isolation of a hyperhemolytic/hyperpigmented GBS strain due to acovR/Smutation from an adolescent patient with persistent sore throat who was also diagnosed with mononucleosis. The isolation of GBS CovR/S mutants indicates their presence in settings of co-infections and includes adolescents.
authors.affiliation: Department of Pediatrics, University of Washington School of Medicine, USA.|Department of Global Health, University of Washington School of Public Health, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Whidbey
authors.affiliation: Department of Pediatrics, University of Washington School of Medicine, USA.
authors.forename: Kellie
authors.initials: K
authors.lastname: Burnside
authors.affiliation: Department of Laboratory Medicine, University of Washington School of Medicine, USA.
authors.forename: Raquel M
authors.initials: RM
authors.lastname: Martinez
authors.affiliation: Seattle Children's Research Institute, USA.
authors.forename: Claire
authors.initials: C
authors.lastname: Gendrin
authors.affiliation: Department of Pediatrics, University of Washington School of Medicine, USA.|Department of Global Health, University of Washington School of Public Health, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Vornhagen
authors.affiliation: Department of Global Health, University of Washington School of Public Health, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Frando
authors.affiliation: Seattle Children's Research Institute, USA.
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Harrell
authors.affiliation: Department of Pediatrics, University of Washington School of Medicine, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: McAdams
authors.affiliation: Seattle Children's Research Institute, USA.|Department of Global Health, University of Washington School of Public Health, USA.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Rajagopal
keywords: Adolescent; Co-infections; CovR; Hyperhemolysis; Hyperpigmentation; Streptococcus agalactiae