Quinolone resistance mutations in Klebsiella pneumoniae

Single-strand conformational polymorphism (SSCP) analysis of 20 quinolone-resistant clinical isolates of Klebsiella pneumoniae showed five mobility patterns. DNA sequence analysis of these fragments revealed that DNA fragments with a mutation (s) in the gyrA gene showed different patterns from the pattern of the wild type gyrA fragment and that one mutation group yielded the specific mobility pattern, which enabled us to anticipate the mutation (s) in the gyrA gene by SSCP analysis. When transformed with the wild type Escherichia coli gyrA gene, the mutants tested became quinolone susceptible, suggesting that the gyrA mutations are responsible for quinolone resistance.