The goal of this study was to determine the resistance mechanism to fluoroquinolones in Salmonella isolates and investigate the association of quinolone resistance with mutations in the genes encoding for DNA gyrase
and topoisomerase IV of S.
Reduced susceptibility to fluoroquinolones is usually associated with point mutations in the bacterial target genes encoding DNA gyrase
and/ or DNA topoisomerase IV within the 'quinolone resistance determining region' (QRDR).
The molecule has two heads that dock into separate pockets in DNA gyrase
, and together they are 100 times more powerful than when working individually.
Quinolone-resistant Neisseria gonorrhoeae: correlation of alterations in the GyrA subunit of DNA gyrase
and the ParC subunit of topoisomerase IV with antimicrobial susceptibility profiles.
A single point mutation in the DNA gyrase
A protein reduces binding of fluoroquinolones to the gyrase
It combines to DNA gyrase
, topoisomerase IV enzymes, intervenes with strand opening and resealing function through DNA replication in the bacteria .
The target genes for multiplex PCR were as follow: the DnaB-like protein gene on the cryptic plasmid of CT, the porin protein A (porA) gene (pseudogene) of NG, the DNA gyrase
(gyrA) gene of MG, the glyceraldehyde 3-phosphate dehydrogenase (gap) gene of MH, the urease (ureG-D) gene of UU, and the b-tubulin 1 (btub1) gene of TV.
Correlation between quinolone susceptibility patterns and sequences in the A and B subunits of DNA gyrase
One of these was also 4-quinolone sensitive with wildtype gyrase
and topoisomerase IV genes.
is composed of two A (GyrA) and two B (GyrB) subunits encoded by gyrA and gyrB genes.
Identification of DNA gyrase
A mutations in ciprofloxacin-resistant isolates of Salmonella typhimurium from men and cattle in Germany.