In Silico Analysis of Amino acid Substitutions in DNA gyrase subunit A

The broad consumption of antibiotics such as fluoroquinolones and the genetic adaption of opportunistic pathogenic bacteria including Pseudomonas aeruginosa, has led to develop of floroquinolone-resistant strains of Pseudomonas aeruginosa. Thus, the aim of the present study is to reveal the types of hot spot mutations occurring in selected DNA gyrase subunit A gene in fluoroquinolone-resistant Pseudomonas aeruginosa strains. For this purpose, 70 fluoroquinolone-resistant partial cds genes of Pseudomonas aeruginosa TOHO strains (P12-P377) for DNA gyrase subunit A have been aligned with wild genes for DNA gyrase subunit A by BLAST program and multiple alignment, to detect probable gyrA mutations. Based on analyses hot spot mutations including Thr-83→Ile (92.44%), Ile-83→Thr (1.33%), Asn-87→Asp (0.44%) existing as single and Thr-83→Ile & Asn-87→Asp (5.78%) as double substitutions were detected. According to this survey, the point mutations in DNA gyrase subunit A gene need more consideration about fluroquinolone-resistant Pseudomonas aeruginosa isolates. The strains with hot spot SNP mutations may rise a huge concern from epidemiologic aspect for antibiotic therapy treatment.