title: Different growth rates of Chlamydia trachomatis biovars reflect pathotype.
abstract: BACKGROUND
  Despite small genomic differences, Chlamydia trachomatis biovars exhibit diverse disease manifestations and different growth rates in vivo and in cell culture models.
  
  
  METHODS
  Chlamydial inclusion-forming units were enumerated over time in HeLa cells, to evaluate the length of the developmental cycle for C. trachomatis strains A, B, C, and E/Bour (ocular strains) as well as D, E/UW5/Cx, F, and L2 (genital strains). Prototype strains A, D, and L2 were selected for detailed analysis of reticulate body growth, division, and genomic replication. The impact that changing host cells and that coinfection with different strains has on growth was also assessed.
  
  
  RESULTS
  The genital strains completed the developmental cycle in 36-44 h, whereas the ocular strains lagged behind considerably. Differences were the result of a longer lag phase (entry plus differentiation) and generation time for the ocular strains. A prototype ocular strain grew faster in conjunctival cells than in cervical cells. Coinfection with genital (D or L2) and ocular strains expedited recovery of the ocular strain.
  
  
  CONCLUSIONS
  Precise temporal evaluation of the chlamydial developmental cycle for selected genital and ocular C. trachomatis biovars provides a means for investigating genomic differences that define chlamydial pathotype.
authors.affiliation: Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
authors.forename: Isao
authors.initials: I
authors.lastname: Miyairi
authors.forename: Olaimatu S
authors.initials: OS
authors.lastname: Mahdi
authors.forename: Scot P
authors.initials: SP
authors.lastname: Ouellette
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Belland
authors.forename: Gerald I
authors.initials: GI
authors.lastname: Byrne
mesh_terms: D002692:Chlamydia trachomatis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity; D003228:Conjunctiva / Q000166:cytology / Q000382:microbiology; D048749:Cytokinesis / Q000235:genetics / Q000502:physiology; D004261:DNA Replication; D004847:Epithelial Cells / Q000382:microbiology; D005260:Female; D006367:HeLa Cells; D006801:Humans; D010406:Penicillins / Q000494:pharmacology; D014141:Trachoma / Q000382:microbiology; D002575:Uterine Cervicitis / Q000382:microbiology
chemical_list: D010406:Penicillins