Molecular mechanisms of fluoroquinolone resistance in Pseudomonas aeruginosa isolates from cystic fibrosis patients.
Twenty P. aeruginosa isolates were collected from six cystic fibrosis (CF) patients, aged 27 to 33, in 1994 (9 isolates) and 1997 (11 isolates) at the CF Center, Copenhagen, Denmark, and were typed by pulse-field gel electrophoresis (PFGE) or ribotyping. Five of the patients had isolates with the same PFGE or ribotyping patterns in 1997 as in 1994, and ciprofloxacin had a two- to fourfold higher MIC for the isolates collected in 1997 than those from 1994. Genomic DNA was amplified for gyrA, parC, mexR, and nfxB by PCR and sequenced. Eleven isolates had mutations in gyrA, seven isolates had mutations at codon 83 (Thr to Ile), and four isolates had mutations at codon 87 (Asp to Asn or Tyr). Sixteen isolates had mutations in nfxB at codon 82 (Arg to Leu). Increased amounts of OprN were found in six isolates and OprJ in eight isolates as determined by immunoblotting. No isolates had mutations in parC or mexR. Six isolates had mutations in efflux pumps without gyrA mutations. The average number of mutations was higher in isolates from 1997 than in those from 1994. The results also suggested that efflux resistance mechanisms are more common in isolates from CF patients than in strains from urine and wounds from non-CF patients, in which mutations in gyrA and parC dominate (S. Jalal and B. Wretlind, Microb. Drug Resist. 4:257-261, 1998).
Jalal
S
S
Division of Clinical Bacteriology, Huddinge University Hospital, S-14186 Huddinge, Sweden. shah.jalal@impi.ki.se
Ciofu
O
O
Hoiby
N
N
Gotoh
N
N
Wretlind
B
B
D000328:Adult; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002939:Ciprofloxacin / Q000494:pharmacology*; D003550:Cystic Fibrosis / Q000382:microbiology*; D027081:DNA Gyrase; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009643:Norfloxacin / Q000494:pharmacology; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D014157:Transcription Factors
D000890:Anti-Infective Agents; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C077901:NfxB protein, Pseudomonas aeruginosa; C105708:OprN protein, Pseudomonas aeruginosa; D014157:Transcription Factors; D002939:Ciprofloxacin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II; D009643:Norfloxacin