Drug resistance mediated by outer membrane porin F (OmpF) and its regulatory gene of micF in Shigella strains
10.3760/cma.j.issn.0254-5101.2016.09.008
- VernacularTitle:志贺菌临床株膜孔蛋白OmpF及调控基因micF介导耐药机制的研究
- Author:
Haojie ZHANG
;
Yang SUN
;
Fengyun LIU
;
Yuchi JIA
;
Wei QI
- Publication Type:Journal Article
- Keywords:
Shigella;
Antibiotic resistance;
Outer membrane porin F;
micF gene
- From:
Chinese Journal of Microbiology and Immunology
2016;36(9):686-691
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the mechanism of drug resistance mediated by micF gene and outer membrane porin F ( OmpF) in Shigella strains. Methods Shigella strains were isolated from stool samples of patients who presented to the Second Hospital of Tianjin Medical University with acute diar-rhea in 2015. Antibiotic susceptibility test was performed to screen out the multidrug-resistant and non-multi-drug-resistant strains. The ompF gene was amplified by PCR. The micF and ompF genes at transcriptional levels in the two groups of strains were detected by quantitative real-time RT-PCR. Intracellular concentra-tions of ciprofloxacin in the two groups of Shigella strains were measured by automatic microplate reader. Re-sults According to the result of antibiotic susceptibility test, 13 strains that were resistant to 3 or more than 3 antibiotics were classified into the multidrug-resistant group, while the other 8 strains that were sensitive to all antibiotics used in this study or only resistant to 1 or 2 antibiotic were classified into the non-multidrug-re-sistant group. All of the 21 Shigella strains carried the ompF gene. Compared with the non-multidrug-resist-ant strains, the multidrug-resistant strains showed higher expression of micF gene, but lower expression of ompF gene. The differences in micF and ompF genes between the two groups were statistically significant. The result of correlation analysis suggested that there was a negative correlation between micF and ompF genes (r=-0. 244). The intracellular concentrations of ciprofloxacin in multidrug-resistant strains were low-er than those in the non-multidrug-resistant strains (P<0. 001). Conclusion The decreased expression of OmpF was one of the possible mechanisms of multidrug-resistance in Shigella strains. The micF gene was negatively related to the expression of OmpF. Moreover, the decreased intracellular concentrations of cipro-floxacin in multidrug-resistant strains might be related to the decreased expression of OmpF.
