Open AccessCorrelation of Overexpression of Efflux Pump Genes with Antibiotic Resistance inEscherichia coliStrains Clinically Isolated from Urinary Tract Infection Patients
Author(s) -
Tomihiko Yasufuku,
Katsumi Shigemura,
Toshiro Shirakawa,
Minori Matsumoto,
Yuzo Nakano,
Kazushi Tanaka,
Soichi Arakawa,
Shouhiro Kinoshita,
Masato Kawabata,
Masato Fujisawa
Publication year - 2011
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.00827-10
Subject(s) - efflux , escherichia coli , antibiotics , microbiology and biotechnology , nalidixic acid , biology , antibiotic resistance , gene , genetics
Escherichia coli is one of the most common pathogens in urinary tract infections (UTIs), and antibiotic resistance inE. coli is becoming a serious problem in treating UTI. Efflux system overexpression is reported to contribute toE. coli resistance to several antibiotics. This study investigated the correlation of antibiotic susceptibilities with the overexpression of the efflux pump genes such asmarA ,yhiU ,yhiV , andmdfA and with risk factors for antibiotic resistance inE. coli isolated from UTI patients. We examined the expression level of efflux pump genes using quantitative real-time reverse transcription-PCR (qRT-PCR). We also tested thein vitro susceptibilities to 12 kinds of antibiotics in 64 clinical strains ofE. coli isolated from UTI patients. By multivariate analyses we revealed significant relationships between the overexpression of (i)marA and MICs of cefepime (FEP) and nalidixic acid (NAL), (ii)yhiV and MICs of minocycline (MIN), and (iii)mdfA and MICs of sitafloxacin (STX). In our investigation of the efflux pump genes, risk factors such as gender and the previous use of fluoroquinolones correlated with the overexpression ofmarA , and indwelling catheter use correlated with the overexpression ofmdfA . In conclusion, we demonstrated that the increased expression of efflux pump genes such asmarA andmdfA can lead to fluoroquinolone resistance inE. coli . These results contribute to our knowledge of the efflux system and raise the possibility of developing new agents, such as efflux pump inhibitors (EPIs), to antibiotic-resistantE. coli .