[Impact of non-target gene mutations and reduced permeability of outer membrane on quinolone resistance and multiple antibiotic resistance in Escherichia coli].
OBJECTIVE
To investigate the impact of non-target gene mutations and reduced permeability of the outer membrane on quinolone resistance and multiple antibiotic resistance (mar) in Escherichia coli.


METHODS
Several high-level quinolone resistant isolates whose strains were accompanied by concurrent resistant to several antibiotics were selected. The PCR products of marOR region were sequenced to detect the possible gene changes and then the strains' outer membrane proteins (Omps) were extracted to analyze on the constitutive profiles.


RESULTS
We found two site mutations in R410 isolate: 1,870(T-->C, Val-->Ala) and 1,879(A-->C, terminator-->Ser). The OmpF deficiency was found in all 3 resistant strains.


CONCLUSIONS
The increased expression of MarA induced by gene mutations in marOR and the constitutive profile changes of the Omps (OmpF deficient strains) may play some role in the quinolone resistance and multiple antibiotic resistance of Escherichia coli.
Zhao
Rui-hua
RH
Department of Microbiology, Xiangya School of Medicine, Central South University, Changsha 410078, China.
Shu
Ming-xing
MX
Chen
Shu-zhen
SZ
D001425:Bacterial Outer Membrane Proteins / Q000187:drug effects / Q000378:metabolism*; D002506:Cephalexin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D019450:Genes, MDR; D016366:Open Reading Frames / Q000235:genetics; D010539:Permeability; D017354:Point Mutation; D015363:Quinolones / Q000494:pharmacology*; D013753:Tetracycline Resistance / Q000235:genetics
D001425:Bacterial Outer Membrane Proteins; D015363:Quinolones; D002506:Cephalexin