Background and Aim : The aim of this study was phenotypic and molecular evaluation of fosfomycin and
colistin resistant in accordance to
ESBL production among
E. coli isolates from UTI after kidney transplantation. Methods : ۶۰
E. coli isolates from urine samples of kidney transplant patients with UTIs from ۳ different Kidney transplant centers in Tehran were collected during ۲۰۱۸-۱۹. Antimicrobial susceptibility test(AST) was done based on the CLSI ۲۰۱۸. Minimum inhibitory concentration (MIC) of fosfomycin was performed by E-test. Further
ESBL phenotypic screening by double disk synergy test(DDST) was evaluated. Molecular survey of
ESBL genes ( including; CTX-M, TEM, SHV), some of fosfomycin resistance (uhpT, murA) genes and mcr-۱ gene as plasmidic
colistin resistance were detected by PCR after DNA extraction. As control, K. pneumonia ATCC ۷۰۰۶۰۳, a fosfomycin resistant and a
colistin resistant E.coli isolates which were bestow from Dr. C. Giske (Karolinska, Sweden) were evaluated simultanously. Sequencing was done by Bioneer Korean company and further analysis and blasting was done in data bank/NCBI.Results : Based on AST, highest susceptibility was to: doripenem, ertapenem (۱۰۰%) and Imipenem ۹۵%, and the highest resistant rate was to: ampicillin (۸۶%), cefotaxime (۸۰%), cefazolin and cefpodoxime (۷۷%). Of ۶۰
E. coli isolates, ۲۷(۴۵%) were associated with multidrug resistance (MDR) phenotype. Only (۳.۳%) of
E. coli isolates showed intermediate resistant (MIC ۱۲۸µg/ml) to fosfomycin based on the E- test. By DDST, ۴۶% of isolates were identified as ESBLs producer. The frequency of
ESBL genes were: blaTEM (۵۴%), blaCTX-M (۵۱%) and blaSHV (۴۰%) and mcr-۱ (۳.۳%) respectively by PCR. Mutation in different points of uhpT and murA genes were detected after sequencing analysis. Conclusion : Frequency of fosfomycin resistant was not high in this study, but, coexistence of
ESBL and fosfomycin plasmidic resistance genes in
E. coli isolates among kidney transplant patients, show the importance of awareness among infection-control practitioners and physicians during prescription. Also,
colistin is not a recommended antibiotic for treatment and during AST for
E. coli isolates by CLSI. But detection of mcr-۱ gene among ۳.۳% of isolates is alarming because it can be exchange between different bacteria and may increase globally soon.