Increased Quinolone-Resistant Mutations of gyrA and parC Genes after Pouchitis Treatment with Ciprofloxacin

Background:Oral antibiotics, such as ciprofloxacin (CFX), are widely used for the treatment of acute and chronic pouchitis. Most bacterial mutations that confer quinolone resistance are at Ser-83 and Asp-87 in thegyrAgene and Ser-80 and Glu-84 in theparCgene.Methods:We obtained 51 stool samples from 43 patients who were diagnosed with ulcerative colitis and underwent ileal pouch-anal anastomosis. Patients were divided into 2 groups: 13 patients with CFX treatment of pouchitis and 30 patients without pouchitis. After extraction of fecal DNA, the amount ofEscherichia coli 16S rRNA,gyrA, andparCgene DNA were measured using real-time polymerase chain reaction (PCR). Possible mutations atgyrA83 and 87 and atparC80 and 84 were investigated by PCR cloning and sequencing, and mutation rates were quantified by rapid PCR-restriction fragment length polymorphism.Results:Samples from both CFX-treated and -untreated patients had comparable levels ofgyrAandparCgene DNA. Nucleic acid and amino acid mutations were identified atgyrA83 and 87, and atparC80 and 84. We successfully quantified mutation rates atgyrA83 and 87, and atparC84, all of which were significantly higher in samples from CFX-treated patients (70, 84, and 38%) than from CFX-untreated patients (13, 11, and 5%).Conclusion:E. coliin patient pouches may have mutations in theirgyrAandparCgenes that produce CFX resistance. Mutation rates of these genes were significantly higher in samples from CFX-treated patients. This study contributes to understanding the decrease and loss of CFX effectiveness against pouchitis.