title: Risk factors for gyrA and parC mutations in Pseudomonas aeruginosa.
abstract: OBJECTIVE
  The major mechanism of fluoroquinolone (FQ) resistance in Pseudomonas aeruginosa (PSA) is modification of target proteins in DNA gyrase and topoisomerase IV, most commonly the gyrA and parC subunits. The objective of this study was to determine risk factors for PSA with and without gyrA or parC mutations.
  
  
  METHODS
  Case-case-control study
  
  
  METHODS
  Two adult academic acute-care hospitals
  
  
  METHODS
  Case 1 study participants had a PSA isolate on hospital day 3 or later with any gyrA or parC mutation; case 2 study participants had a PSA isolate on hospital day 3 or later without these mutations. Controls were a random sample of all inpatients with a stay of 3 days or more.
  
  
  METHODS
  Each case group was compared to the control group in separate multivariate models on the basis of demographics and inpatient antibiotic exposure, and risk factors were qualitatively compared.
  
  
  RESULTS
  Of 298 PSA isolates, 172 (57.7%) had at least 1 mutation. Exposure to vancomycin and other agents with extended Gram-positive activity was a risk factor for both cases (case 1 odds ratio [OR], 1.09; 95% confidence interval [CI], 1.04-1.13; OR, 1.14; 95% CI, 1.03-1.26; case 2 OR, 1.09; 95% CI, 1.03-1.14; OR, 1.13; 95% CI, 1.01-1.25, respectively).
  
  
  CONCLUSIONS
  Exposure to agents with extended Gram-positive activity is a risk factor for isolation of PSA overall but not for gyrA/parC mutations. FQ exposure is not associated with isolation of PSA with mutations.
authors.affiliation: 1Division of Infectious Diseases,Department of Medicine,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Valerie C
authors.initials: VC
authors.lastname: Cluzet
authors.affiliation: 1Division of Infectious Diseases,Department of Medicine,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Ebbing
authors.initials: E
authors.lastname: Lautenbach
authors.affiliation: 4Department of Pathology and Laboratory Medicine,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Irving
authors.initials: I
authors.lastname: Nachamkin
authors.affiliation: 2Center for Clinical Epidemiology and Biostatistics,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Cary
authors.affiliation: 1Division of Infectious Diseases,Department of Medicine,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Neil O
authors.initials: NO
authors.lastname: Fishman
authors.affiliation: 4Department of Pathology and Laboratory Medicine,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Natalie N C
authors.initials: NN
authors.lastname: Shih
authors.affiliation: 2Center for Clinical Epidemiology and Biostatistics,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Knashawn H
authors.initials: KH
authors.lastname: Morales
authors.affiliation: 1Division of Infectious Diseases,Department of Medicine,Perelman School of Medicine,University of Pennsylvania,Philadelphia,Pennsylvania.
authors.forename: Darren R
authors.initials: DR
authors.lastname: Linkin
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use; D016022:Case-Control Studies; D003428:Cross Infection / Q000235:genetics / Q000382:microbiology; D027081:DNA Gyrase / Q000235:genetics*; D027101:DNA Topoisomerase IV / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D064704:Levofloxacin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D011552:Pseudomonas Infections / Q000235:genetics / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D012307:Risk Factors; D014640:Vancomycin / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D064704:Levofloxacin; D014640:Vancomycin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase