Determination of uhpT gene expression in E. coli isolates of UTIs among kidney transplant patients

Background and Aim : E.coli is the main gram negative responsible for urinary tract infections (UTIs) specially in kidney transplant patients(KTPS Defects in one or both of the transport systems caused by mutations in the uhpT and glpT structural genes or the regulators can confer fosfomycin resistance. Our aim is to investigate uhpT gene expression in the presence of glucose ۶ phosphate among E.coli isolates from UTIs of kidney transplant patients.Methods : A total of ۶۰ clinical isolates of uropathogenic E. coli were collected from ۳ kidney transplant centers from April to May ۲۰۱۹. Antimicrobial susceptibility testing was performed by the disk diffusion method as recommended by the CLSI. Fosfomycin resistant isolates were determined by E-test. The serotyping of E. coli isolates was performed by the slide agglutination method. PCR and further sequencing was performed for ESBL genes (SHV, TEM and CTX-M genes), fosA۳, fosC۲, uhpT, glpT and cyaA genes and then real-time PCR was performed for genes uhpT in the presence of glucose ۶ phosphate and lack thereof. A fosfomycin resistant E.coli isolate dedicated from Prof. C. Giske (Karolinska Institute, Sweden) was evaluated simultaneously.Results : The frequency of ESBL-producing E. coli in KTPs was found to be ۳۳.۴%. All of the ۶۰ E. coli were found to be susceptible to doripenem and ertapenem (۱۰۰%). High resistance rates to ampicillin (۸۶%), cefotaxime (۸۰%), and cefazolin (۷۷%) were also documented. We identified mutations in murA, uhpT, glpT genes in resistant samples after sequencing and gene bank alignment. No fosA۳ and fosC۲ genes were identified. According to the E-test, the resistance to fosfomycin in our samples was ۱.۶% and including ۲ intermediate and a resistant isolates. According to the real-time PCR test, the expression of one of the two sensitive samples increased ۳۲ times in comparison to intermediate and resistant isolates.Conclusion : There is a discrepancy between the data from in vitro and clinical studies regarding development of resistance. This may be because of the complex biological phenomenon of infection, in which there is interplay between bacteria, antibiotics, site of infection, presence of foreign materials and function of the immune system. Ultimately, the current fosfomycin activity seems to be more than satisfactory and justifies its use as monotherapy or in combination with other antibiotics for treatment of infections caused by susceptible and multidrug-resistant bacteria.

کلیدواژه ها:

E .coli ، Urinary tract infections ، Fosfomycin