title: Coincidental outbreak of methicillin-resistant Staphylococcus aureus in a hematopoietic stem cell transplantation unit.
abstract: BACKGROUND
  Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens among hospital-acquired infections, and immunocompromised patients are highly susceptive to infection. The molecular typing of isolated strains is a common method for tracing an outbreak of MRSA, but experience with this approach is still limited in the hematopoietic stem cell transplantation (HSCT) ward.
  
  
  METHODS
  We experienced 6 cases of MRSA infection/colonization in our 26-bed HSCT ward during a 4-week period. This unusual outbreak strongly suggested that the same MRSA strain was involved despite strict isolation and aseptic patient care. Clarification of the transmission pattern was critical, and we applied pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) assays for evaluation.
  
  
  CONCLUSIONS
  In four of the six cases, the pattern of bands examined by PFGE and AFLP analyses supported the idea that direct person-to-person transmission was very unlikely and the outbreak was coincidental. This experience highlights the clinical value of molecular typing methods for the clinical epidemiological assessment of MRSA outbreak.
authors.affiliation: Hematopoietic Stem Cell Transplantation Unit, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Imataki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Makimoto
authors.forename: Shingo
authors.initials: S
authors.lastname: Kato
authors.forename: Takahiro
authors.initials: T
authors.lastname: Bannai
authors.forename: Naomi
authors.initials: N
authors.lastname: Numa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nukui
authors.forename: Yuji
authors.initials: Y
authors.lastname: Morisawa
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ishida
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kami
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fukuda
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Mori
authors.forename: Ryuji
authors.initials: R
authors.lastname: Tanosaki
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takaue
mesh_terms: D000328:Adult; D002173:Cancer Care Facilities / Q000592:standards; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000592:standards; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D012150:Polymorphism, Restriction Fragment Length; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*