Wenzhou Medical University, School of Laboratory Medicine and Life Sciences, Wenzhou, China.
The First Affiliated Hospital of Wenzhou Medical University, Department of Clinical Laboratory, Wenzhou, China.
Braz J Infect Dis. 2019 Jan-Feb;23(1):15-21. doi: 10.1016/j.bjid.2019.01.004. Epub 2019 Feb 21.
To evaluate the influence of sub-minimum inhibitory concentrations (MICs) of ciprofloxacin (CIP) on biofilm formation and virulence factors of Escherichia coli clinical isolates.
Sub-MICs of CIP were determined using growth curve experiments. The biofilm-forming capacity of E. coli clinical isolates and E. coli ATCC 25922 treated or untreated with sub-MICs of CIP was assessed using a crystal violet staining assay. The biofilm structure of E. coli isolate was assessed with scanning electron microscopy (SEM). The expression levels of the virulence genes fim, usp, and iron and the biofilm formation genes of the pgaABCD locus were measured using quantification RT-PCR (qRT-PCR) in E. coli isolates and E. coli ATCC 25922.
Based on our results, the sub-MICs of CIP were 1/4 MICs. Sub-MICs of CIP significantly inhibited biofilm formation of E. coli clinical isolates and E. coli ATCC 25922 (p<0.01). SEM analyses indicated that the biofilm structure of the E. coli changed significantly after treatment with sub-MICs of CIP. Expression levels of the virulence genes fim, usp, and iron and the biofilm formation genes of the pgaABCD locus were also suppressed.
The results revealed that treatment with sub-MICs of CIP for 24h inhibited biofilm formation and reduced the expression of virulence genes and biofilm formation genes in E. coli.
评估环丙沙星（CIP）亚最小抑菌浓度（MIC）对大肠杆菌临床分离株生物膜形成和毒力因子的影响。
采用生长曲线实验确定 CIP 的亚 MIC。采用结晶紫染色法评估未经和经 CIP 亚 MIC 处理的大肠杆菌临床分离株和大肠杆菌 ATCC 25922 的生物膜形成能力。采用扫描电子显微镜（SEM）评估大肠杆菌分离株的生物膜结构。采用定量 RT-PCR（qRT-PCR）测量大肠杆菌分离株和大肠杆菌 ATCC 25922 中毒力基因 fim、usp 和铁以及 pgaABCD 基因座生物膜形成基因的表达水平。
根据我们的结果，CIP 的亚 MIC 为 1/4 MIC。CIP 的亚 MIC 显著抑制大肠杆菌临床分离株和大肠杆菌 ATCC 25922 的生物膜形成（p<0.01）。SEM 分析表明，经 CIP 亚 MIC 处理后，大肠杆菌的生物膜结构发生了显著变化。毒力基因 fim、usp 和铁以及 pgaABCD 基因座生物膜形成基因的表达水平也受到抑制。
结果表明，用 CIP 亚 MIC 处理 24 小时可抑制生物膜形成，并降低大肠杆菌中毒力基因和生物膜形成基因的表达。
