title: Ciprofloxacin resistance among nosocomial Pseudomonas aeruginosa and Staphylococcus aureus in the United States.
abstract: OBJECTIVE
  We attempted to determine if an increase in resistance to ciprofloxacin occurred among nosocomial pathogens, especially Pseudomonas aeruginosa and Staphylococcus aureus.
  
  
  METHODS
  We examined 1989-1992 ciprofloxacin susceptibility results from 8,517 P aeruginosa and 9,021 S aureus isolates associated with nosocomial infections reported to the National Nosocomial Infections Surveillance System.
  
  
  RESULTS
  For S aureus, 27.1% of isolates were resistant to ciprofloxacin; of methicillin-resistant S aureus isolates, 80% also were resistant to ciprofloxacin. A logistic regression model found that ciprofloxacin resistance was more common among S aureus isolated from the urinary and respiratory tracts than from other sites of isolation, and among isolates that were methicillin resistant. After controlling for these factors, the model showed a 123% increase in the odds of ciprofloxacin resistance from 1989-1990 to 1991-1992. For P aeruginosa, 4.7% of the isolates were resistant to ciprofloxacin. Resistance varied by site of infection and rose most dramatically for respiratory tract isolates from 2.0% in 1989-1990 to 5.3% in 1991-1992.
  
  
  CONCLUSIONS
  Resistance to ciprofloxacin is more frequent among nosocomial S aureus than among P aeruginosa and is increasing rapidly among S aureus isolates and from selected sites among P aeruginosa isolates.
authors.affiliation: Hospital Infections Program, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: V G
authors.initials: VG
authors.lastname: Coronado
authors.forename: J R
authors.initials: JR
authors.lastname: Edwards
authors.forename: D H
authors.initials: DH
authors.lastname: Culver
authors.forename: R P
authors.initials: RP
authors.lastname: Gaynes
mesh_terms: D002939:Ciprofloxacin / Q000494:pharmacology*; D003428:Cross Infection / Q000382:microbiology; D004352:Drug Resistance, Microbial; D006801:Humans; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012307:Risk Factors; D013211:Staphylococcus aureus / Q000187:drug effects*; D013997:Time Factors; D014481:United States
chemical_list: D002939:Ciprofloxacin