title: Intracellular reservoir of Streptococcus pyogenes in vivo: a possible explanation for recurrent pharyngotonsillitis.
abstract: Numerous theories have been presented that attempt to explain the frequent recurrences of pharyngotonsillitis caused by Streptococcus pyogenes; these recurrences occur after seemingly adequate antibiotic treatment. We previously have demonstrated that Spyogenes can survive for up to 7 days intracellularly in immortalized human respiratory epithelial cells grown in an antibiotic supplemented medium. Viable S pyogenes were externalized and established an extracellular infection, whenever the extracellular antibiotic was removed. We have investigated the presence of intracellular S pyogenes in two in vivo studies using respiratory epithelial cells collected from patients with tonsillitis and the tonsils of asymptomatic carriers. Electron microscopy and immunohistochemistry demonstrated intracellular S pyogenes in pharyngeal epithelial cells in 13 of 14 patients with tonsillitis (93%). Furthermore, intracellular S pyogenes were found in macrophage-like cells in eight (73%) and in epithelial cells in four (36%) tonsils from 11 asymptomatic S pyogenes carriers. These in vivo data strongly support the hypothesis that intracellular S pyogenes can constitute a reservoir of bacteria with the potential to cause reinfections.
authors.affiliation: Department of Clinical Microbiology, University Hospital, Uppsala, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Osterlund
authors.forename: R
authors.initials: R
authors.lastname: Popa
authors.forename: T
authors.initials: T
authors.lastname: Nikkilä
authors.forename: A
authors.initials: A
authors.lastname: Scheynius
authors.forename: L
authors.initials: L
authors.lastname: Engstrand
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002981:Clindamycin / Q000627:therapeutic use; D004197:Disease Reservoirs; D004848:Epithelium / Q000382:microbiology / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D007962:Leukocytes / Q000382:microbiology* / Q000648:ultrastructure; D008264:Macrophages / Q000382:microbiology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008875:Middle Aged; D014066:Palatine Tonsil / Q000382:microbiology* / Q000473:pathology; D010406:Penicillins / Q000627:therapeutic use; D010612:Pharyngitis / Q000188:drug therapy / Q000382:microbiology*; D012008:Recurrence; D013297:Streptococcus pyogenes / Q000302:isolation & purification*; D014069:Tonsillitis / Q000188:drug therapy / Q000382:microbiology* / Q000601:surgery
chemical_list: D010406:Penicillins; D002981:Clindamycin