title: Contamination of Phenylobacterium in several human and murine cell cultures.
abstract: OBJECTIVE
  To identify and characterize an unknown microorganism causing contamination in several mammalian cell cultures.
  
  
  METHODS
  This bacterium was identified by 16S rRNA sequencing and studied by DAPI and DiOC6 (3) staining, Gram staining, acid-fast staining, and electron microscopy. The isolated bacterium was also used to infect host cells to observe antibiotic effectiveness and its relationship with host cells.
  
  
  RESULTS
  The 16S rRNA sequence analysis shows that this rod-shaped microorganism belongs to the family Caulobacteraceae, class Alphaproteobacteria, and was most closely related to Phenylobacterium zucineum HLK1T strain. The bacterium collected in the "swimming" stage was Gram staining negative, but Gram staining positive in the "sessile" stage. Under the electron microscope both flagellated and non-flagellated types were found. So far, no antibiotics were effective to inhibit this microorganism. The contamination with this bacterium frequently led to failed resuscitation of thawed cells. We found that the cells resuscitated with the used culture supernatants were increased in number by 3-4 folds as compared to those resuscitated with freshly prepared media.
  
  
  CONCLUSIONS
  Phenylobacterium may have a dimorphic life cycle including a swimming stage and a sessile stalked stage.
authors.forename: Tianqing
authors.initials: T
authors.lastname: Xiong
authors.forename: Dengli
authors.initials: D
authors.lastname: Wang
authors.forename: Baihong
authors.initials: B
authors.lastname: Tan
authors.forename: Wenhua
authors.initials: W
authors.lastname: Jiang
authors.forename: Gaoyue
authors.initials: G
authors.lastname: Dai
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao
authors.forename: Shulei
authors.initials: S
authors.lastname: Li
authors.forename: Yanchao
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D042063:Caulobacteraceae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D018929:Cell Culture Techniques; D002460:Cell Line / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D006801:Humans; D051379:Mice; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S