title: Evidence of interhospital transmission of extended-spectrum beta-lactam-resistant Klebsiella pneumoniae in the United States, 1986 to 1993. The National Nosocomial Infections Surveillance System.
abstract: BACKGROUND
  In addition to single-hospital outbreaks, interhospital transmission of extended-spectrum beta-lactam-resistant (ESBLR) Klebsiella pneumoniae has been suspected in some reports. However, these studies lacked sufficient epidemiological information to confirm such an occurrence.
  
  
  METHODS
  We reviewed the surveillance data reported to the National Nosocomial Infections Surveillance (NNIS) System during 1986 to 1993 for K pneumoniae isolates and their susceptibility to either ceftazidime, cefotaxime, ceftriaxone, or aztreonam. Pulsed-field gel electrophoresis (PFGE) was used to study available ESBLR K pneumoniae isolates.
  
  
  RESULTS
  Among 8,319 K pneumoniae isolates associated with nosocomial infections, 727 (8.7%) were resistant or had intermediate-level resistance to at least one of these antibiotics. One hospital (hospital A) accounted for 321 isolates (44.2%) of ESBLR K pneumoniae. During 1986 to 1993, the percentage of K pneumoniae isolates that were ESBLR increased from 0 to 57.7% in hospital A, from 0 to 35.6% in NNIS hospitals 0 to 20 miles from hospital A (area B), and from 1.6 to 7.3% in NNIS hospitals more than 20 miles from hospital A, including hospitals located throughout the United States. Analysis of PFGE restriction profiles showed a genetic relationship between a cluster of isolates from hospital A and some isolates from one hospital in area B, and consecutive admission in these two hospitals was confirmed for two patients from whom isolates were available.
  
  
  CONCLUSIONS
  These data provide evidence of interhospital transmission of ESBLR K pneumoniae in one region of the United States and stress the interrelationship between hospitals when trying to control antimicrobial resistance.
authors.affiliation: Hospital Infections Program, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Monnet
authors.forename: J W
authors.initials: JW
authors.lastname: Biddle
authors.forename: J R
authors.initials: JR
authors.lastname: Edwards
authors.forename: D H
authors.initials: DH
authors.lastname: Culver
authors.forename: J S
authors.initials: JS
authors.lastname: Tolson
authors.forename: W J
authors.initials: WJ
authors.lastname: Martone
authors.forename: F C
authors.initials: FC
authors.lastname: Tenover
authors.forename: R P
authors.initials: RP
authors.lastname: Gaynes
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology* / Q000635:transmission; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000635:transmission; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics; D017720:Molecular Epidemiology; D011159:Population Surveillance; D012044:Regression Analysis; D014481:United States / Q000453:epidemiology; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D047090:beta-Lactams